RESUMO

Mammals express four isoforms of glycerol-3-phosphate acyltransferase (GPAT). The mitochondrial isoform GPAT1 may have been the acyltransferase that appeared first in evolution. The hepatopancreas of the crustacean Macrobrachium borellii has a high capacity for triacylglycerol (TAG) biosynthesis and storage. In order to understand the mechanism of glycerolipid biosynthesis in M. borellii, we investigated its hepatopancreas GPAT activity. In hepatopancreas mitochondria, we identified a GPAT activity with characteristics similar to those of mammalian GPAT1. The activity was resistant to inactivation by SH-reactive N-ethylmaleimide, it was activated by polymyxin-B, and its preferred substrate was palmitoyl-CoA. The reaction products were similar to those of mammalian GPAT1. A 70-kDa protein band immunoreacted with an anti-rat liver GPAT1 antibody. Surprisingly, we did not detect high GPAT specific activity in hepatopancreas microsomes. GPAT activity in microsomes was consistent with mitochondrial contamination, and its properties were similar to those of the mitochondrial activity. In microsomes, TAG synthesis was not dependent on the presence of glycerol-3 phosphate as a substrate, and the addition of monoacylglycerol as a substrate increased TAG synthesis 2-fold. We conclude that in M. borellii the de novo triacylglycerol biosynthetic pathway can be completed in the mitochondria. In contrast, TAG synthesis in the ER may function via the monoacylglycerol pathway.

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Previous studies report on the differences in volume of osteocytic lacunae that are associated to different local and systemic bone pathologies. Alterations have also been reported in rats with periodontal disease. The aim of the present study was to assess the histomorphometric pattern of osteocytic lacunae of the interradicular septum in human molars with periodontal disease (PD). We took samples of the interradicular septum of 31 molars with indication of extraction of male and female patients, 18-55 years old, who attend the Department of Surgery II of the Faculty of Dentistry, National University of Cordoba and private centers. Clinical records were prepared for each patient. The corresponding radiographs were taken for all the patients. We studied 11 samples of molars with slight PD and 12 control molars free from PD. Ten samples of healthy bone corticals of vestibular or lingual tables obtained from histopathology archives were also assessed. Following extraction with atraumatic pincers, the interradicular septum was removed. The samples were fixed in buffered formaline, decalcified in EDTA and embedded in paraffin. Ten micrometer sections were stained with H&E and Masson's trichromic technique. The sections were analyzed by light microscopy. A minimum of 50 lacunae were selected at random in each sample for histomorphometric evaluation. Semi-automatic evaluation of the area and diameters of the lacunae was performed employing an image analyzer and the PRO IMAGE PLUS software. The data showed that the volume of osteocytic lacunae of interradicular bone is larger than that of the cortical bone of the vestibular or lingual tables. The latter are more ribbon-shaped and their minor diameter is smaller. No differences were found between the osteocytic lacunae of the interradicular bone of healthy molars and that of molars with slight periodontal disease. Given that the experimental data evidenced volume changes in osteocytic lacunae of severe, inflammatory periodontal lesions, it would be interesting to examine the volume changes in osteocytic lacunae in patients with varying degrees of periodontal disease to examine the role of osteocytes in the development and progression of periodontal disease.

Assuntos

RESUMO

Previous studies report on the differences in volume of osteocytic lacunae that are associated to different local and systemic bone pathologies. Alterations have also been reported in rats with periodontal disease. The aim of the present study was to assess the histomorphometric pattern of osteocytic lacunae of the interradicular septum in human molars with periodontal disease (PD). We took samples of the interradicular septum of 31 molars with indication of extraction of male and female patients, 18-55 years old, who attend the Department of Surgery II of the Faculty of Dentistry, National University of Cordoba and private centers. Clinical records were prepared for each patient. The corresponding radiographs were taken for all the patients. We studied 11 samples of molars with slight PD and 12 control molars free from PD. Ten samples of healthy bone corticals of vestibular or lingual tables obtained from histopathology archives were also assessed. Following extraction with atraumatic pincers, the interradicular septum was removed. The samples were fixed in buffered formaline, decalcified in EDTA and embedded in paraffin. Ten micrometer sections were stained with H&E and Massons trichromic technique. The sections were analyzed by light microscopy. A minimum of 50 lacunae were selected at random in each sample for histomorphometric evaluation. Semi-automatic evaluation of the area and diameters of the lacunae was performed employing an image analyzer and the PRO IMAGE PLUS software. The data showed that the volume of osteocytic lacunae of interradicular bone is larger than that of the cortical bone of the vestibular or lingual tables. The latter are more ribbon-shaped and their minor diameter is smaller. No differences were found between the osteocytic lacunae of the interradicular bone of healthy molars and that of molars with slight periodontal disease. Given that the experimental data evidenced volume changes in osteocytic lacunae of severe, inflammatory periodontal lesions, it would be interesting to examine the volume changes in osteocytic lacunae in patients with varying degrees of periodontal disease to examine the role of osteocytes in the development and progression of periodontal disease.

RESUMO

Previous studies report on the differences in volume of osteocytic lacunae that are associated to different local and systemic bone pathologies. Alterations have also been reported in rats with periodontal disease. The aim of the present study was to assess the histomorphometric pattern of osteocytic lacunae of the interradicular septum in human molars with periodontal disease (PD). We took samples of the interradicular septum of 31 molars with indication of extraction of male and female patients, 18-55 years old, who attend the Department of Surgery II of the Faculty of Dentistry, National University of Cordoba and private centers. Clinical records were prepared for each patient. The corresponding radiographs were taken for all the patients. We studied 11 samples of molars with slight PD and 12 control molars free from PD. Ten samples of healthy bone corticals of vestibular or lingual tables obtained from histopathology archives were also assessed. Following extraction with atraumatic pincers, the interradicular septum was removed. The samples were fixed in buffered formaline, decalcified in EDTA and embedded in paraffin. Ten micrometer sections were stained with H&E and Masson’s trichromic technique. The sections were analyzed by light microscopy. A minimum of 50 lacunae were selected at random in each sample for histomorphometric evaluation. Semi-automatic evaluation of the area and diameters of the lacunae was performed employing an image analyzer and the PRO IMAGE PLUS software. The data showed that the volume of osteocytic lacunae of interradicular bone is larger than that of the cortical bone of the vestibular or lingual tables. The latter are more ribbon-shaped and their minor diameter is smaller. No differences were found between the osteocytic lacunae of the interradicular bone of healthy molars and that of molars with slight periodontal disease. Given that the experimental data evidenced volume changes in osteocytic lacunae of severe, inflammatory periodontal lesions, it would be interesting to examine the volume changes in osteocytic lacunae in patients with varying degrees of periodontal disease to examine the role of osteocytes in the development and progression of periodontal disease.

RESUMO

The effect of the liposoluble organophosphorus insecticide fenitrothion (FS) on lipid packing and rotation of two crustacean plasma HDL was investigated. These lipoproteins, HDL-1 and HDL-2, differed in their lipid composition, but their lipid/protein ratios were similar. The rotational behavior of the fluorescent probes 1,6-diphenyl-1,3,5-hexatriene (DPH) and 3-(p-(6-phenyl)-1,3,5-hexatrienyl) phenylpropionic acid (DPH-PA) was used to obtain information about the lipid dynamics in the outer and inner regions, respectively, of the lipid phase of the lipoproteins. Fluorescent steady-state anisotropy (r(s)), lifetime (tau), rotational correlation time (tau(r)), and the limiting anisotropy (r(infinity)) of these probes were measured in the lipoproteins exposed to different concentrations of FS in vitro. The results showed the penetration of FS into both plasma lipoproteins, altering the lipid dynamics of the inner as well as the outer regions. The overall effect of the insecticide was to induce an increase in the lipid order in a concentration-dependent fashion. DPH and DPH-PA fluorescence-lifetime shortening indicated that FS increased the polarity of the probe environment, suggesting an enhanced water penetration into the lipoprotein lipid phase, may be due to the induction of failures in the lipid packing. Even in the absence of FS, a higher ordering of the lipid phase was found in HDL-2 compared to HDL-1, a fact that might be attributed to a higher percentage of sphingomyelin in HDL-2.

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RESUMO

The mitochondrial isoform of glycerol-3-phosphate acyltransferase (GPAT), the first step in glycerolipid synthesis, is up-regulated by insulin and by high carbohydrate feeding via SREBP-1c, suggesting that it plays a role in triacylglycerol synthesis. To test this hypothesis, we overexpressed mitochondrial GPAT in Chinese hamster ovary (CHO) cells. When GPAT was overexpressed 3.8-fold, triacylglycerol mass was 2.7-fold higher than in control cells. After incubation with trace [(14)C]oleate ( approximately 3 microm), control cells incorporated 4.7-fold more label into phospholipid than triacylglycerol, but GPAT-overexpressing cells incorporated equal amounts of label into phospholipid and triacylglycerol. In GPAT-overexpressing cells, the incorporation of label into phospholipid, particularly phosphatidylcholine, decreased 30%, despite normal growth rate and phospholipid content, suggesting that exogenous oleate was directed primarily toward triacylglycerol synthesis. Transiently transfected HEK293 cells that expressed a 4.4-fold increase in GPAT activity incorporated 9.7-fold more [(14)C]oleate into triacylglycerol compared with control cells, showing that the effect of GPAT overexpression was similar in two different cell types that had been transfected by different methods. When the stable, GPAT-overexpressing CHO cells were incubated with 100 microm oleate to stimulate triacylglycerol synthesis, they incorporated 1.9-fold more fatty acid into triacylglycerol than did the control cells. Confocal microscopy of CHO and HEK293 cells transfected with the GPAT-FLAG construct showed that GPAT was located correctly in mitochondria and was not present elsewhere in the cell. These studies indicate that overexpressed mitochondrial GPAT directs incorporation of exogenous fatty acid into triacylglycerol rather than phospholipid and imply that (a) mitochondrial GPAT and lysophosphatidic acid acyltransferase produce a separate pool of lysophosphatidic acid and phosphatidic acid that must be transported to the endoplasmic reticulum where the terminal enzymes of triacylglycerol synthesis are located, and (b) this pool remains relatively separate from the pool of lysophosphatidic acid and phosphatidic acid that contributes to the synthesis of the major phospholipid species.

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The effects of the organophosphorous insecticide fenitrothion (phosphorothioic acid, O,O-dimethyl O-(3-methyl-4-nitrophenyl) ester; FS) on the physical state of pure dipalmitoyl (DPPC) and 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) membranes were investigated. FS lowers the phase transition temperature of DPPC. It has no large effects on the DPPC gel phase, but it increases the order of the liquid-crystalline state of DPPC and POPC. FS also decreases 1,6-diphenyl-1,3,5-hexatriene (DPH) lifetime (tau) in the DPPC and POPC liquid-crystalline states. Since a direct quenching of DPH emission by FS was ruled out, tau shortening is assigned to an increased water penetration in the bilayer. The effect of FS is different from most perturbing agents for which an increased order is accompanied by a higher tau. Furthermore, quenching of DPH by KI was increased by FS in POPC liposomes indicating an increased accessibility of the quencher to the hydrophobic core where DPH distributes. The effect of FS on dipole relaxation at the hydrophilic-hydrophobic interface of POPC bilayers was studied with 2-dimethylamino-6-lauroylnaphthalene (Laurdan). FS produces a decrease in Laurdan tau and a narrowing of its emission band. FS significantly increases the generalized polarization values at both emission band ends. These results indicate that FS may allow the coexistence of microdomains that have different physical properties.

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Energy partitioning, composition of lipids and fatty acids, and their utilization by embryos were determined in the lecithotrophic shrimp Macrobrachium borellii during seven development stages. The biochemical composition at stage I is represented by lipids, proteins, and carbohydrates, with 29.3, 28.7, and 0.2% dry weight, respectively. The former two were identified as the major energy-providing components, contributing 131 and 60 cal/100 mg egg, dry weight, respectively. The overall conversion efficiency (CE) was 45.0% (calculated as percentage of vitelline energy transformed into embryonic tissues). Lipids were the most important energy reserve (CE 39.3%), followed by proteins (CE 57.1%), both being simultaneously utilized during development while carbohydrates were synthesized de novo (CE 587.5%). Variation in the lipid class composition of embryos and vitellus showed an accumulation of triacylglycerols (TAG) and phospholipids (PL) up to stage IV, a more active accumulation and selective utilization phase (stages V and VI), and a consumption and de novo synthesis period until hatching. Structural lipids (PL and cholesterol) and pigment astaxanthin were selectively conserved in embryos, but TAG, hydrocarbons, and esterified sterols were preferentially depleted. Monounsaturated fatty acids (FA) were the major group in TAG, whereas polyunsaturated FA (PUFA) were the major group in PL after organogenesis. Certain PUFA such as 22:6n-3 and 20:5n-3 were selectively accumulated in PL.

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The activities of the enzymatic systems involved in the activation and degradation of fatty acids, and in the synthesis of triacylglycerols and phospholipids were studied in vitro using total cellular homogenate and subcellular fractions of eggs of the shrimp Macrobrachium borellii at different developing stages. Egg development was divided into seven stages based on morphological features of the embryo. Palmitoyl-CoA ligase activity increased as the embryo developed and showed its maximum at stage V. An increase in the synthesis of triacylglycerols and diacylglycerols was also observed at this stage. Diacylglycerylethers were synthesized more actively during the first stages of development. The higher specific activity observed in total homogenate than in microsomal fraction suggested that their synthesis was not exclusively microsomal. Phospholipid synthesis was very active all along development, reflecting active membrane biosynthesis. The highest activity of the cytosolic triacylglycerol lipase was observed at stage V. Fatty acid degradation, measured as mitochondrial beta-oxidation activity, did not vary significantly during development. We conclude that both the anabolic and catabolic processes concerning lipid metabolism are very active, with values similar to those described for adult hepatopancreas, revealing the major role of lipids during shrimp embryogenesis energetics, and that the highest activities of lipid synthesis-hydrolysis take place at stage V when embryos are under active organogenesis. J. Exp. Zool. 286:231-237, 2000.

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Since the identification of the first case of Hantavirus infection in Chile in 1995, a great advance in the knowledge of the disease natural history has occurred. There is evidence to suppose that the infection by Andes virus in suburban areas of Argentina and Chile, whose natural reservoir is Oligoryzomys longicaudatus, has been present but unidentified for a long time. We describe a serologically proven case occurred in 1975. The clinical presentation of the disease slightly differs from that described for Hantavirus Pulmonary Syndrome (HPS), caused by Sin Nombre virus in the USA. There is a wider range of presentation forms including, besides HPS, mild and asymptomatic cases, a greater proportion of renal involvement and pediatric cases. Therefore the epidemiological scenario would be an endemic disease with fluctuations that follow changes in rodent population and their interactions with humans.

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RESUMO

An outbreak of 25 cases of Andes virus-associated hantavirus pulmonary syndrome (HPS) was recognized in southern Chile from July 1997 through January 1998. In addition to the HPS patients, three persons with mild hantaviral disease and one person with asymptomatic acute infection were identified. Epidemiologic studies suggested person-to-person transmission in two of three family clusters. Ecologic studies showed very high densities of several species of sigmodontine rodents in the area.

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RESUMO

The objective was to evaluate the effect of the endoscopic treatment of the polycystic ovary syndrome (PCOS) in a murine model induced with depot estrogen. Three groups with PCOS were studied: group 1 (n = 22) evaluated exclusively using laparoscopy; group 2 (n = 11) one fulguration on both ovaries was performed during laparoscopy; and group 3 (n = 10) three fulgurations were performed. One month after laparoscopy the animal were sacrificed and was carried surgical microscopic examination of the intraabdominal organs, moreover histological evaluation of the gonads was practiced. All the animals showed PCOS. No adhesions were observed in the animals of group 1, while the frequency of adhesion in group 2 was 36.3%, 18.1% of the animals of group 2 showed gonadal atrophy. The frequency of adhesions in the group 3 was 66.6%. The adhesion score was significantly higher in groups 2 and 3 than in group 1. Is concluded that the use of estrogen is useful to induce PCOS in animal models. The procedure can be employed to study the effects of the surgical induction of ovulation, it's utility in other conditions seems promissary.

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The aim of this work was to study the usefulness of CSF adenosine deaminase determination in the diagnosis of tuberculous meningitis and determine if the proposed cutoff value of 7.1 i.u./ml had the better sensitivity and specificity. We retrospectively studied 148 patients, 12 with tuberculous meningitis and 136 with other central nervous system diseases. Adenosine deaminase values ranged from 3.6 to 31.2 i.u./ml in patients with tuberculous meningitis and from 0.1 to 312 i.u./ml in controls. The best sensitivity/specificity ratio (83.3 and 85.3% respectively) was obtained using a cutoff value of 6.5 i.u./ml. It is concluded that CSF adenosine deaminase values are useful in the diagnosis of tuberculous meningitis and that the cutoff value should be lowered to 6.5 i.u./ml to improve its diagnostic yield.

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We report a 47 year old woman that presented to the hospital with an intracranial hypertension syndrome, a right hemiparesis and a several months history of progressive malaise and behavioral disturbances. During the hospital stay, positive HIV antibodies were detected and CAT scan showed a profound left parietal rounded hypodense lesion. The patient died 21 days after admission and the postmortem pathological study showed a deep abscess in the left basal ganglia, with recognizable Toxoplasma gondii trophozoites.

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In this review of 159 pts with systemic lupus erythematosus (SLE) followed for 18 years, 78 pts had major infections (20/100 pt-years). Patients with infection had a higher incidence of proteinuria, central nervous system involvement, the use of methylprednisolone boluses and mortality rate. Infection was independent of the amount of steroids and immunosuppressor drugs used. Microorganisms were isolated in 77% of the cases, gram negative enterobacteria were the most common isolates. 30% of the pts had pulmonary infection; and 84% of the infections happened during steroid therapy. Immunosuppression was associated to repeated infections. The 19 pts with fatal infections had a higher frequency of pneumonia and septicemia, and received high doses of steroids (> or = 40 mg). No relation to immunosuppression was found in this group. In 26% opportunistic microorganisms were isolated in association to the use of high doses of steroids. Even if survival of SLE has improved in the last 40 years, infections are still an important cause of mortality, most of them related to aggressive steroid therapy.

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A study is made of the morbidity in the Orthopedics service of Sur Children's Hospital in Santiago de Cuba and the results of nursing care during the first trimester of 1986 in 100 randomly selected in-patients. The highest incidence among the diagnosis corresponded to fractures, infectious process of soft tissues and osteomyelitis. By means of the medical history evaluation it was demonstrated that nursing care was appropriate in the period analyzed.

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