RESUMEN
AIM: The therapeutic model for severe obesity includes bariatric surgery, representing the safest way to keep weight down and to prevent relapses. The selection of patients for the most suitable type of surgery implies multidisciplinary approach (nutritionist, dietist, clinical psychologist and surgeon). The intragastric balloon may represent a relatively invasive method to help the medical team to select and prepare severely obese patients for restrictive bariatric surgery. METHODS: In our study we considered 48 severely obese patients: initial weight 111+/-14.8 kg, BMI 43+/-5.02, excess weight 77.47+/-16.14%. These patients have been treated with intragastric balloon (BIB) filled to a volume of 500 cc for 6 months. We considered variations induced by BIB treatment on a number of parameters--clinical, anthropometric, food intake, partition of nourishing elements and psychological and psychometric data. RESULTS: At the end of the treatment the patients showed significant reductions of excess weight (67.35+/-20.19%), of weight (103.4+/-16.72 kg) and food intake, without modification of the items in the EDI2 test, but with important motivational support for a change in life style between the beginning and the end of the treatment, clearly resulting from the medical, dietist and clinical-psychological follow-up. CONCLUSIONS: BIB is a relatively invasive means capable of modifying eating habits in the short term; it induces weight loss, may help to reduce the anaesthesiological risk and to foster a change in the patient's behaviour. In our experience treatment with BIB is useful from the educational point of view and can be used to select patients for bariatric surgery only within a multidisciplinary team. Further clinical studies are necessary.
Asunto(s)
Ingestión de Alimentos , Balón Gástrico , Estilo de Vida , Obesidad Mórbida/terapia , Pérdida de Peso , Adulto , Peso Corporal , Remoción de Dispositivos , Ingestión de Energía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Obesidad Mórbida/psicología , Factores de Tiempo , Resultado del TratamientoRESUMEN
The paper reports a histological and immunohistochemical description of oocyte growth and ultrastructural aspects of zona radiata (ZR) formation as well as the relationship between plasma estradiol-17beta, (E2) levels and ovarian development in swordfish (Xiphias gladius L.) from the Mediterranean Sea. Ovaries were inactive during March to mid April; maturation occurred during late April to June and spawning in June and July. Zona radiata formation starts, as Pas positive material, in oocytes at the lipid stage. In this stage a deposit of electrondense material between oolemma and follicular cells appears. In the cortical alveoli stage and through the early vitellogenic stage, the deposition of a moderately electrondense material occurred on the inner side of the ZR. Finally, in late vitellogenic oocytes a third layer, made of microfibrillar material, appeared. The immunohistochemical analyses revealed that the initial internalisation of hepatic zona radiata proteins (Zrp) in the swordfish oocyte starts before the uptake of vitellogenin (Vtg) and that it is associated with the low previtellogenic E2 plasma levels, while a significant E2 increase in plasma is associated with the beginning of Vtg uptake. This would appear to confirm the hypothesis that the differential and sequential induction of zonagenesis and vitellogenesis may reflect a general feature of teleost oogenesis.
Asunto(s)
Estradiol/sangre , Ovario/anatomía & histología , Ovario/crecimiento & desarrollo , Perciformes/crecimiento & desarrollo , Perciformes/metabolismo , Animales , Femenino , Inmunoglobulina G/sangre , Inmunohistoquímica , Oocitos/citología , Ovario/ultraestructura , Perciformes/anatomía & histologíaRESUMEN
Prenatal exposure to low concentrations of carbon monoxide (CO, 75 and 150 ppm from day 0 to day 20 of gestation), resulting in maternal blood HbCO concentrations equivalent to those maintained by human cigarette smokers, leads to subtle myelin alterations in the sciatic nerve of male rat offspring. The rapid growth spurt in pup body weight was related to the period of maximal increase in myelin sheath thickness in both control and CO-exposed animals. A significant reduction in myelin sheath thickness of sciatic nerve fibers, paralleled by changes in the frequency distribution, occurred in both 40- and 90-day-old rats exposed in utero to CO (75 and 150 ppm). Myelin deficit observed in 75 and 150 ppm CO-exposed animals showed up only after the major spurt in myelination but not early during development. The subtle myelin alterations observed in CO-exposed offspring were not accompanied by changes in developmental pattern of axon diameters and did not result in a gross impairment of motor activity. These results suggest that the myelination process is selectively targeted by a prenatal exposure model simulating the CO exposure observed in human cigarette smokers.
Asunto(s)
Monóxido de Carbono/toxicidad , Vaina de Mielina/efectos de los fármacos , Vaina de Mielina/metabolismo , Efectos Tardíos de la Exposición Prenatal , Nervio Ciático/efectos de los fármacos , Animales , Axones/efectos de los fármacos , Axones/metabolismo , Axones/ultraestructura , Peso Corporal/efectos de los fármacos , Carboxihemoglobina/metabolismo , Relación Dosis-Respuesta a Droga , Femenino , Exposición por Inhalación , Masculino , Actividad Motora/efectos de los fármacos , Actividad Motora/fisiología , Embarazo , Ratas , Ratas Wistar , Análisis de Regresión , Nervio Ciático/embriología , Nervio Ciático/metabolismoRESUMEN
The pars distalis from the pituitary gland of adult male ruin lizards (Podarcis sicula campestris De Betta), captured during the five periods of the annual sexual cycle (emergence from hibernation, reproductive period, summer regression, autumnal recrudescence, winter arrest), was studied immunohistochemically using specific antibodies against hFSHbeta, hLHbeta, oFSHbeta, and oLHbeta with the avidin-biotin complex (ABC) procedure to monitor the seasonal changes in shape, size and percentage area taken up from gonadotropes. FSH containing cells were specifically identified with anti-hFSHbeta and anti-oFSHbeta sera, whereas the LH cells were localized by anti-hLHbeta. The anti-oLHbeta serum showed cross-reactivity with the cells immunostained by the three above antisera (anti-hFSHbeta, anti-oFSHbeta, and anti-hLHbeta). None of the cells contained both gonadotropic hormones as shown by the double-immunostaining procedure. Generally, FSH cells were larger and more numerous than LH cells. FSH cells were elongated or pyriform in shape from spring to autumn, whereas they were round or oval during the winter stasis and until the emergence from hibernation. The size and the percentage area occupied by FSH cells showed an annual pattern with two distinct peaks in the reproductive and in the autumnal recrudescence periods. LH cells did not show seasonal changes in shape, being round or oval throughout the reproductive cycle, whereas their size and the area they occupied underwent seasonal variations. The LH cells reached the largest size during the reproductive period and the smallest size during the summer regression. The percentage area occupied by LH cells in the pars distalis peaked at the emergence from hibernation and during the summer refractory period, when FSH cells displayed their lowest values.
Asunto(s)
Hormona Folículo Estimulante/metabolismo , Lagartos/fisiología , Hormona Luteinizante/metabolismo , Hipófisis/metabolismo , Animales , Humanos , Técnicas para Inmunoenzimas , Lagartos/metabolismo , Masculino , Hipófisis/citología , Estaciones del AñoRESUMEN
PURPOSE: This study was undertaken to establish the pattern of specific p53 gene mutations in prostate cancer within primary tumors and distant metastases. MATERIALS AND METHODS: We performed polymerase chain reaction-single-strand conformation polymorphism and sequencing analyses of p53 exons 5-8 in DNA extracted from 22 formalin-fixed, paraffin-embedded tissues from 17 patients. Samples from three patients included specimens from primary and metastatic sites (paired specimens). RESULTS: G:C-to-A:T transitions were the most common point mutations (64%). Six (55%) of 11 G:C-to-A:T transitions occurred at CpG dinucleotides in five hot-spot codons (175, 245, 248, 273, and 282). Sequencing analysis of the paired samples revealed that two of the three pairs had the same mutation in both. Sequencing analysis of DNA from a different area of one of the primary tumors revealed a different mutation in the p53 gene. CONCLUSIONS: Our results suggest that specific p53 mutations participate in the progression of human prostate cancer. These findings support those of others that indicate that the primary cancer is heterogeneous and clonal expansion occurs during the progression of clinically detectable prostate cancer. Our data also imply that p53 mutations at the primary site may be predictive of metastases.
Asunto(s)
Neoplasias Óseas/genética , Neoplasias Óseas/secundario , Genes p53/genética , Mutación , Neoplasias de la Próstata/genética , Anciano , Humanos , Inmunohistoquímica , Masculino , Neoplasias de la Próstata/química , Proteína p53 Supresora de Tumor/análisis , Proteína p53 Supresora de Tumor/biosíntesisRESUMEN
The pars distalis from the pituitary gland of adult male ruin lizards (Podarcis sicula campestris De Betta), captured during the reproductive period (May and June), was studied immunohistochemically using specific antibodies against hFSH beta, hLH beta and oLH beta with the avidin-biotin-peroxidase complex (ABC) procedure to determine the localization of both gonadotropins. The immunostaining with anti-hFSH beta and anti-hLH beta allowed identification of morphologically distinct FSH containing cells and LH containing cells, whereas anti-oLH beta serum showed cross-reactivity with cells immunostained with the anti-hFSH beta and anti-hLH beta sera. The gonadotropic cells took up approximatively 10.5% of the area of the pars distalis: 10% was positive for FSH, whereas only 0.5% was positive for LH. The FSH cells were distributed throughout the pars distalis, whereas the LH cells were only located in the rostral region. Double-immunostaining procedure did not reveal cells containing both gonadotropic hormones. The findings indicate that FSH and LH are produced in separate pituitary cells.
Asunto(s)
Hormona Folículo Estimulante/análisis , Hormona Luteinizante/análisis , Hipófisis/química , Animales , Técnicas para Inmunoenzimas , Lagartos , Masculino , Hipófisis/patologíaRESUMEN
Malignant mesothelioma is one of the very few extrarenal neoplasms in which the Wilms tumor suppressor gene (wt1) is expressed. We examined wt1 for alterations in rat mesotheliomas, a well characterized animal model for the human disease. Southern analysis revealed a 3.5 kb EcoRI wt1 fragment readily detectable in majority of mesothelioma cell lines and primary mesotheliomas but not in normal rat tissues. Cloning and sequencing of this fragment revealed that the presence of this EcoRI fragment resulted from an inability of this enzyme to cut at a EcoRI site in intron 1 of wt1. This site contains potential motifs for cytosine methylation and treatment of mesothelioma cells with 5-azadeoxycytosine restored the normal EcoRI digestion pattern of wt1 in these cells indicating that cleavage was inhibited by methylation at this site. Southern analysis using HpaII/MspI digestion revealed no differences in methylation between mesothelioma cell lines and normal mesothelium at other CpG sites in wt1 5' region. Renal cell carcinoma lines which did not express wt1 were also methylated at this EcoRI site. Our identification of a site frequently methylated in malignant cells, independent of gene expression, provides a new model system to study determinants of site-specific methylation in tumors.
Asunto(s)
Metilación de ADN , ADN de Neoplasias/metabolismo , Proteínas de Unión al ADN/genética , Genes del Tumor de Wilms , Mesotelioma/genética , Factores de Transcripción/genética , Animales , Sitios de Unión , Islas de CpG , Citosina/metabolismo , Desoxirribonucleasa EcoRI/metabolismo , Desoxirribonucleasa HpaII/metabolismo , Exones , Intrones , Mesotelioma/inducido químicamente , Ratas , Ratas Wistar , Células Tumorales Cultivadas , Proteínas WT1RESUMEN
Existing models of mouse mammary carcinogenesis induced by the model polycyclic aromatic hydrocarbon 7,12-dimethylbenz[a]anthracene (DMBA) typically use a small number of bolus doses applied intragastrically. In contrast to this, typical human exposures to carcinogens are thought to be at lower doses and to occur with chronic or sporadic timing. When the classical dosage (1 mg DMBA given once a week for 6 weeks) was split into five daily doses of 200 microg given intragastrically to female SENCAR mice each week for 6 weeks, toxicity was high and the major tumor type seen was lymphoma. Lowering the dose to 60 microg/day gave less toxicity, a 75% incidence of lymphoma and a 30% incidence of mammary carcinoma. However, 20 microg DMBA given five times per week for 6 weeks resulted in a 65-70% incidence of mammary carcinoma within approximately 50 weeks. This represents a 50-fold lower daily dosage of DMBA than that used in the classical model. DNA was prepared from 10 mammary adenocarcinomas and 10 lymphomas and exons 1 and 2 of the H-ras1, K-ras and N-ras genes were sequenced using PCR techniques. Mutations altering codons 12 or 61 of one of the ras family genes were found in 4/10 mammary carcinomas and 5/10 lymphomas. Three mammary tumors exhibited codon 61 mutations, one in each of the genes studied, and a fourth tumor contained a codon 12 mutation in the K-ras gene. Among the lymphomas, two mutations in codon 12 of K-ras, one mutation in codon 61 of K-ras and two mutations in codon 61 of N-ras were also found. Each of the mutations could be interpreted as a G-->T or A-->T transversion. It is suggested that the high incidence of lymphoma at the higher, repetitive doses may be related to immunotoxicity. These low dose models of lymphomagenesis and mammary carcinogenesis should prove useful for tests of chemopreventive agents that target the initiation phase of carcinogenesis.
Asunto(s)
9,10-Dimetil-1,2-benzantraceno/administración & dosificación , Adenocarcinoma/inducido químicamente , Carcinógenos/administración & dosificación , Genes ras/efectos de los fármacos , Linfoma/inducido químicamente , Neoplasias Mamarias Experimentales/inducido químicamente , Adenocarcinoma/genética , Administración Oral , Animales , Codón/genética , Análisis Mutacional de ADN , ADN de Neoplasias/genética , Relación Dosis-Respuesta a Droga , Femenino , Linfoma/genética , Neoplasias Mamarias Experimentales/genética , Ratones , Ratones Endogámicos SENCAR , Especificidad de Órganos , Mutación Puntual , Reacción en Cadena de la PolimerasaRESUMEN
The epididymal ductuli efferentes of the lizard Podarcis sicula campestris De Betta are lined with simple, columnar, nonciliated and ciliated cells. The use of lectin histochemistry has provided information about changes of sugars associated with glycoconjugates of epithelial cells and intraluminal spermatozoa which are conveyed from the longitudinal canal to the cranial region of the ductus epididymis. Epithelial cells exhibited residues of alpha-D-mannose, N-acetylglucosamine, and beta-D-galactose-(1-4)-N-acetylglucosamine as revealed with lectins Con A, WGA and RCA120, respectively, throughout the sexual cycle. An increase of RCA120 staining was observed on microvilli of nonciliated cells and in the cytoplasm of ciliated cells during the reproductive period. However, during the following refractory period, when the organ was in regression, there was a decreased staining with Con A on microvilli and the absorbent surface of nonciliated cells, with WGA in nonciliated cells and the cytoplasm of ciliated cells, and with RCA120 on microvilli and the cytoplasm of both cell types. Terminal alpha-D-galactose residues were increasingly stained from autumn up to the reproductive period with BS I-B4 on microvilli, the absorbent surface and cilia, whereas they were entirely lacking during the refractory period. UEA I revealed alpha-L-fucose residues on the absorbent surface of nonciliated cells during the abortive and reproductive periods, increasing in the latter period when cilia also expressed this sugar. Terminal alpha/beta-D-N-acetylgalactosamine was evidenced with SBA on the absorbent surface of nonciliated cells during the reproductive period. The terminal beta-D-galactose-(1-3)-N-acetylgalactosamine dimer was never found with PNA, whereas O- and N-linked sialoglycoconjugates were present only during the reproductive period. The spermatozoa head exhibited N-linked glycans with high-mannose content, and beta-D-galactose-(1-4)-N-acetylglucosamine as well as O- and N-linked sialoglycoconjugates throughout the year. During the reproductive period, oligosaccharides with alpha-D-mannose residues increased, and oligosaccharides with terminal alpha-D-galactose, alpha-L-fucose and sialic acid-N-acetylgalactosamine dimer were also present. Unlike spermatozoa of seminiferous tubules, the spermatozoa head of the lizard epididymal ductuli efferentes exhibited seasonal variability in the lectin binding pattern which may be related to time-dependent changes in the glycoconjugate profiles of epithelial cells.
Asunto(s)
Epidídimo/química , Glicoconjugados/química , Glicoconjugados/metabolismo , Lagartos/anatomía & histología , Lagartos/metabolismo , Lectinas de Plantas , Conducta Sexual Animal/fisiología , Proteínas de Soja , Animales , Concanavalina A/metabolismo , Epidídimo/anatomía & histología , Epidídimo/metabolismo , Histocitoquímica , Lectinas/metabolismo , Masculino , Aglutinina de Mani , Estaciones del Año , Aglutininas del Germen de Trigo/metabolismoRESUMEN
Chemical induction of mammary tumors in mice requires usually a long latency period and is often complicated by high non-mammary tumor related mortality. Classically hormone stimulation has been used as the means to increase tumor incidence. The synthetic progestin medroxyprogesterone acetate (MPA) was postulated by some authors to increase mammary tumor incidence in various rodent models. However, controversy exists regarding the role of MPA in experimental and human carcinogenesis. In our study we tested the use of a protocol of combined MPA- and dimethylbenz[a]anthracene (DMBA) treatment for the obtention of mammary tumors with a short latency and with a lower toxicity than the classical multiple dose DMBA protocol. MPA was very effective in accelerating the development and increasing the incidence of mammary tumors induced by DMBA in CD2F1 mice. MPA by itself did not produce any mammary tumors. The mean latency for tumor development from the end of carcinogen treatment was 99 +/- 51 days in the group that received a combination of MPA and four DMBA doses. This group showed significantly earlier mammary tumor incidence (P < 0.0001) and higher tumor numbers than the groups that received only DMBA. Mammary tumors were also analyzed for effects on the mutation rate affecting the Ha-ras and Ki-ras genes. Our data is consistent with MPA probably increasing the number of target cells at risk for mutation by the chemical carcinogen DMBA and possibly promoting the faster development of tumors.
Asunto(s)
9,10-Dimetil-1,2-benzantraceno , Adenocarcinoma/inducido químicamente , Carcinógenos , Neoplasias Mamarias Experimentales/inducido químicamente , Acetato de Medroxiprogesterona/toxicidad , Adenocarcinoma/epidemiología , Adenocarcinoma/patología , Animales , Secuencia de Bases , Cartilla de ADN , Sinergismo Farmacológico , Exones , Femenino , Genes ras , Humanos , Incidencia , Neoplasias Mamarias Experimentales/epidemiología , Neoplasias Mamarias Experimentales/patología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos DBA , Reacción en Cadena de la PolimerasaRESUMEN
To confirm that the hamster cheek-pouch carcinogenesis model reflects development of human squamous cell carcinoma (SCC), we determined if and when p53 mutations occur in the development of SCC in this model by using immunohistochemical staining and polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) analysis plus direct DNA sequencing. Twenty-four hamster cheek-pouches were treated with a solution of 0.5% 7,12-dimethylbenz[a]anthracene in mineral oil three times a week for 16 wk. The malignant endophytic and exophytic tumors induced with this protocol are preceded by a sequence of premalignant lesions such as hyperplasia with or without dysplasia and carcinoma in situ, similar to the development of this cancer in humans. For this study, p53 protein accumulation was evaluated by immunostaining of various hamster cheek-pouch exophytic and endophytic SCCs as well as flat dysplastic hyperplasia and carcinomas in situ. A moderate percentage (33.3%) of exophytic lesions and most endophytic carcinomas (90%) showed positive p53 staining. In addition we also found p53-positive staining in a number of preneoplastic lesions, including areas of focal hyperplasia, dysplastic hyperplasia, and carcinomas in situ. To determine whether the alterations in p53 staining were due to p53 gene mutation, we used PCR-SSCP analysis and direct sequencing. PCR products corresponding to exons 5a, 6, 7, and 8 from 40 tumors with the highest percentage of p53-stained cells were analyzed. We detected shifted bands in 17 lesions. Direct sequencing of eight selected shifted bands revealed four mutations, including two G-->T transversions in codons 216 (tumor #1) and 252 (tumor #2) and one G-->C transversion in codon 282 (tumor #3). Tumor #4 contained a frameshift mutation in codon 251. These mutations are consistent with those reported in many human cancers. Therefore, we concluded that in the hamster cheek-pouch model, p53 protein accumulation occurs frequently and early in carcinogenesis, as it does in human SCCs, and some of these p53 alterations are due to p53 gene mutations. These findings may help us better define the mechanisms of carcinogenesis in the hamster cheek-pouch model, and p53 alterations may be an early biomarker of progression for chemoprevention studies.
Asunto(s)
Carcinoma de Células Escamosas/genética , Genes p53 , Neoplasias de la Boca/genética , Mutación , 9,10-Dimetil-1,2-benzantraceno , Animales , Secuencia de Bases , Carcinógenos , Carcinoma de Células Escamosas/inducido químicamente , Carcinoma de Células Escamosas/metabolismo , Mejilla , Cricetinae , Modelos Animales de Enfermedad , Exones , Inmunohistoquímica , Masculino , Mesocricetus , Datos de Secuencia Molecular , Neoplasias de la Boca/inducido químicamente , Neoplasias de la Boca/metabolismo , Reacción en Cadena de la Polimerasa , Polimorfismo Conformacional Retorcido-Simple , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
A previously published method for predicting the frequency of random occurrence of a completely specified DNA oligomer in a longer sequence dataset has been generalized to allow degeneracy in the oligomer sequence. With this enhancement, several datasets consisting of sequences from the human genome were searched for the occurrence of consensus binding sites for a set of 13 transcription factors. Although because of the biological significance of these sequences one might predict that they would occur more often than the random frequency, many of the consensus oligomers were found at lower than expected frequencies. Several (G+C)-rich oligomers were found to be moderately over-represented, but this could be accounted for, in part, by the occurrence of (G+C)-rich tracts in the human sequences. Regions very high in (G+C) were found to occur at much higher frequencies than expected in the human genome, and this severely limits the usefulness of this approach for predicting the frequency of (G+C)-rich oligomers. Unexpectedly, more than 1% of the human genome consists of tracts at least 28 bp in length with a (G+C) content greater than 85%.
Asunto(s)
Genoma Humano , Modelos Genéticos , Oligonucleótidos , Secuencia de Bases , Secuencia de Consenso , Humanos , Datos de Secuencia Molecular , Probabilidad , Factores de Transcripción/genéticaRESUMEN
The distribution of glycoconjugates in the testis of lizard Podarcis s. campestris De Betta was investigated by HRP-conjugated lectins during the annual spermatogenetic cycle. In addition, pretreatments of sections with neuraminidase and removal of alkali-labile O-linked sequences by beta-elimination allowed the structure of glycoconjugates to be further explored. Leydig cells displayed changes of lectin-binding sites during annual cycle, and during the abortive spermatogenesis period lacked N-linked sialylgalactosyl glycans. Sertoli cells stained by Con A, WGA, RCA120, BS I-B4, showed, except in July, O-linked sialylgalactosyl glycans. Spermatogonia bound Con A and WGA. Spermatocytes bound also BS I-B4, SBA, UEA I, and during spring spermatogenesis, revealed O-linked sialylgalactosyl glycans. The acrosomes of spermatids were also stained by RCA120 and PNA, whereas the heads of spermatozoa did not bind SBA and PNA. During the abortive spermatogenic period, the acrosomes showed O-linked sialylgalactosyl glycans and N-linked glycans terminating in beta-galactosyl residues. During the reproductive period, the acrosomes of spermatozoa expressed O- and N-linked sialylgalactosyl glycans and beta-galactosyl terminal residues on O- and N-linked glycans. This, in the testis of lizard, the two spermatogenesis periods show the emergence of different types of glycosylation.
Asunto(s)
Glicoconjugados/análisis , Histocitoquímica/métodos , Lagartos/fisiología , Espermatogénesis/fisiología , Testículo/química , Acrosoma/química , Animales , Membrana Basal/química , Sitios de Unión , Epitelio/anatomía & histología , Epitelio/química , Lectinas/metabolismo , Masculino , Receptores Mitogénicos/análisis , Estaciones del Año , Túbulos Seminíferos/anatomía & histología , Túbulos Seminíferos/química , Testículo/fisiopatologíaRESUMEN
The lectin binding pattern of both Schwann cells and macrophages has been studied during axonal degeneration induced in the rat sciatic nerve by chronic administration of 2,5-hexanedione (0.8 ml/kg per day i.p. for 20 days). In particular, the present study aimed to establish a possible relationship between macrophage activation and expression of lectin binding sites. To identify and distinguish between Schwann cells and macrophages, electron microscopy was combined with the lectin staining method. On 2,5-hexanedione injury, a drastic disorganization of both axon and myelin sheath occurred and nerve fibers were replaced by a chain of ovoids. Besides the well-established concept that Schwann cells and macrophages cooperate in the removal of the myelin debris during axonal degeneration, evidence is presented that expression of binding sites to lectins is closely related to macrophage activation. Monocytes occasionally present in control nerves were labelled only by Con A and sialidase-peanut sequence; in 2,5-hexanedione degeneration monocytes, prephagocytes (macrophages with minute bubbles) and phagocytes (macrophages with large bubbles) were labelled also by peanut, wheat germ and BSA I-B4; moreover, phagocytes were labelled by soybean as well, thus showing a clearly differentiation-dependent binding pattern. Since changes in lectin binding pattern may reflect changes in complex carbohydrate structures, the results show that the expression of certain glycoproteins may be closely related to activation of macrophages in response to toxic injuries.
Asunto(s)
Axones/efectos de los fármacos , Hexanonas/toxicidad , Macrófagos/metabolismo , Degeneración Nerviosa/inmunología , Receptores Mitogénicos/metabolismo , Células de Schwann/metabolismo , Animales , Axones/ultraestructura , Secuencia de Carbohidratos , Células Cultivadas , Masculino , Datos de Secuencia Molecular , Degeneración Nerviosa/efectos de los fármacos , Ratas , Ratas WistarRESUMEN
A polymorphism in the gene for proteolipid protein has been identified, using amplification by the polymerase chain reaction, restriction enzyme digestion, and fragment separation by polyacrylamide gel electrophoresis. The polymorphism is located in the transcribed 3'-untranslated region, a region with potential regulatory signals. The mutation consists of a single base pair insertion into a Hae III restriction site, producing a larger rare fragment of 409 bp as compared with the more frequent 325 bp fragment. The gene for proteolipid protein is on the X chromosome; thus the males are hemizygous for the rare allele and the females are heterozygous carriers. The polymorphism occurs with a frequency of 0.046 in a population of European origin and also has a rare frequency in multiple sclerosis patients.
Asunto(s)
Hominidae/genética , Proteínas de la Mielina/genética , Polimorfismo Genético , Animales , Secuencia de Bases , ADN/sangre , ADN/aislamiento & purificación , Cartilla de ADN , Femenino , Humanos , Masculino , Datos de Secuencia Molecular , Proteína Proteolipídica de la Mielina , Oligonucleótidos Antisentido , Linaje , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Mapeo Restrictivo , Cromosoma XRESUMEN
Myelinated nerve fibres isolated from Wistar rats chronically exposed to 2,5-hexanedione (0.8 ml/kg/day, intraperitoneally) over a period of 20 days, were stained with lectin-horseradish peroxidase conjugates. The lectins with high affinity for terminal D-galactopyranosyl residues, Bandeiraea simplicifolia-B4 (BSA I-B4) and peanut agglutinin (PNA), showed glycoconjugates in the control nodes of Ranvier. In the treated animals, application of PNA-HRP caused weak reactivity to the node of Ranvier; digestion with sialidase prior to the application of PNA-HRP conjugate enhanced reactivity, thus revealing the presence of a sialoglycoprotein. The results indicate that glycoconjugates of the Ranvier node undergo a rearrangement during exposure to 2,5-hexanedione. In particular, neutral glycoproteins with terminal galactose are replaced by sialoglycoproteins. These findings are consistent with the proposed role of polysialic acid as a regulator of axonal behaviour during regeneration.
Asunto(s)
Axones/metabolismo , Hexanonas/toxicidad , Vaina de Mielina/metabolismo , Ácidos Siálicos/metabolismo , Animales , Histocitoquímica , Peroxidasa de Rábano Silvestre , Lectinas/metabolismo , Masculino , Polisacáridos/metabolismo , Nódulos de Ranvier/metabolismo , Ratas , Ratas Wistar , Nervio Ciático/efectos de los fármacos , Regulación hacia ArribaRESUMEN
GAP-43 (a.k.a. B-50, F1, pp46, or neuromodulin) is a major growth cone membrane protein whose expression is widely correlated with successful axon elongation, but whose function remains unknown. To distinguish the structural features of GAP-43 most relevant to its cellular functions, we have determined features of the protein that are most highly conserved in vertebrate evolution. Comparison of fish and mammalian GAP-43 distinguishes two domains of the protein. A strictly conserved amino-terminal domain contains the putative site for fatty acylation and membrane attachment, a calmodulin binding domain, and a proposed phosphorylation site. In the much larger carboxy-terminal domain, amino acid composition is strongly conserved without extensive sequence conservation. This amino acid composition predicts an extended, negatively charged rod conformation with some similarity to the side arms of neurofilaments. The results suggest that the biological roles of GAP-43 may depend on an ability to form a dynamic membrane-cytoskeleton-calmodulin complex.
Asunto(s)
Glicoproteínas de Membrana/genética , Proteínas del Tejido Nervioso/genética , Vertebrados/genética , Animales , Secuencia de Bases , Evolución Biológica , ADN , Peces/genética , Proteína GAP-43 , Genes , Sustancias de Crecimiento/genética , Mamíferos/genética , Datos de Secuencia MolecularRESUMEN
In 25 heroin addicts examined an initial alteration in microcirculatory homeostasis was found ond held to be responsible for the addiction. As in other cases it is thought possible to use the chronobiological course of haemodynamic balance and imbalance as a biological marker for prevention and treatment.
Asunto(s)
Relojes Biológicos , Dependencia de Heroína/fisiopatología , Homeostasis , Microcirculación , Humanos , Síndrome de Abstinencia a Sustancias/etiologíaRESUMEN
Estradiol transiently increases the rate of peptide elongation on uterine ribosomes from ovariectomized mature rats during the first 2 h after hormone injection, suggesting the existence of direct or indirect estradiol receptor interaction with ribosomes. Characterization of estradiol-binding components on isolated uterine ribosomes, microsomes, and cytosol under identical assay conditions indicated that microsomes and cytosol contain estradiol-binding components with similar affinities for estradiol (Kd = 0.5 nM) and sucrose gradient sedimentation characteristics (3.8S and 5.2S for preparations incubated at 0 and 30 C for 1 h, respectively). Those on ribosomes exhibited a higher affinity for estradiol (Kd = 0.14 nM) and had heterogeneous and more dense sedimentation characteristics (5.5-6.0S). The ribosome-associated estradiol binder was clearly different from transformed cytosol and nuclear estradiol receptors based on sedimentation characteristics under identical conditions. Like cytosol and nuclear receptors, microsomal and ribosomal estradiol binding underwent exchange reactions in vitro at 30 C, but not at 0 C. All in vitro bound, but not all in vivo bound, [3H] estradiol could be exchanged from microsomes or ribosomes by estradiol. [3H]Estradiol could be exchanged from ribosomes by a variety of estrogens, but not by progestins, glucocorticoids, or androgens. The amount of estradiol-binding activity on ribosomes decreased after estradiol administration in vivo and was inversely correlated with the rate of peptide elongation by the ribosomes in a cell-free protein synthesis system. These results suggest that accumulation of an estradiol-binding protein, perhaps a nascent estradiol receptor, on ribosomes in the absence of in vivo estradiol may directly or indirectly inhibit the peptide elongation reaction.
Asunto(s)
Estradiol/metabolismo , Extensión de la Cadena Peptídica de Translación , Receptores de Estradiol/metabolismo , Receptores de Estrógenos/metabolismo , Ribosomas/metabolismo , Útero/metabolismo , Animales , Núcleo Celular/metabolismo , Citosol/metabolismo , Femenino , Microsomas/metabolismo , Biosíntesis de Proteínas , ARN Ribosómico/análisis , Ratas , Ratas EndogámicasRESUMEN
Knowledge of the incidence of haemodynamic imbalance syndromes and consequent pathologies in growing children at various ages may be a useful aid to the preventive measures that make for effective treatment of the organs involved in the psychological and physical development of school children. The oscillation between haemodynamic balance and imbalance was monitored in 849 subjects aged 3-18 on the basis of periods of absence relatable to the biorhytmic cycle of each pupil within the daily and seasonable rhythm. The survey identifies the instruments that facilitate natural haemodynamic balance and reduce desynchronising stimuli.