RESUMEN
BACKGROUND: Tuberculous conjunctivitis has been described only rarely during the course of lupus vulgaris. We report a case of hemifacial cutaneous tuberculosis, diagnosed as atypical lupus vulgaris, associated with homolateral fibrosing tuberculous conjunctivitis. PATIENTS AND METHODS: An 83-year-old woman presented inflammatory conjunctivitis without bullous involvement in the left eye leading to corneal neovascularisation, symblepharons and ptosis. Erythematous and atrophic papules were seen on the left side of the face. Biopsy of the skin and conjunctiva revealed a tuberculoid granulomatous infiltrate. Bacterial culture and PCR were both positive for Mycobacterium tuberculosis. DISCUSSION: This case illustrates the need to consider tuberculosis when faced with an atypical facial eruption and ocular involvement.
Asunto(s)
Conjuntivitis Bacteriana/complicaciones , Dermatosis Facial/microbiología , Tuberculosis Cutánea/complicaciones , Tuberculosis Ocular/complicaciones , Anciano de 80 o más Años , Femenino , Humanos , Mycobacterium tuberculosis/aislamiento & purificaciónRESUMEN
A 51-year-old Caucasian man consulted for a visual loss in the left eye due to corneal extension of a conjunctival melanoma. This conjunctival melanoma arose from primary acquired melanosis with atypia at the temporal corneoscleral limbus. The patient was treated using a combination of surgical excision with physical treatment by ocular proton therapy. Progression remained under control 11 months after treatment: no local tumour recurrence or metastasis was observed. Primary acquired melanosis with atypia must be regarded as a premalignant melanocytic lesion. Based on this case report, the authors focus on primary acquired melanosis and its risk of transformation to a conjunctival malignant melanoma.
Asunto(s)
Neoplasias de la Conjuntiva/patología , Limbo de la Córnea/patología , Melanoma/patología , Neoplasias de la Conjuntiva/cirugía , Progresión de la Enfermedad , Humanos , Masculino , Melanoma/cirugía , Persona de Mediana Edad , Lesiones Precancerosas/patología , Resultado del TratamientoRESUMEN
Kaposi's sarcoma (KS) is a mesenchymal tumor involving blood and lymphatic vessels and induced by viral growth factors (HHV8-IL6). This article reviews the epidemiology, pathogenesis, clinical spectrum (classic KS, iatrogenic immunosuppressive KS, endemic African KS, and AIDS-KS), histological features, staging criteria and treatment of KS. Unlike industrialized countries that have benefited from widespread use of highly active antiretroviral therapy (HAART), developing countries continue to have a high incidence of AIDS-KS. Future therapeutic targets for KS are enhancement of immune function and treatment with angiogenesis inhibitors
Asunto(s)
Sarcoma de Kaposi/epidemiología , Sarcoma de Kaposi/terapia , Neoplasias Cutáneas/epidemiología , Neoplasias Cutáneas/terapia , Diagnóstico Diferencial , Enfermedades Endémicas , Infecciones por VIH/complicaciones , Herpesvirus Humano 8/patogenicidad , Humanos , Huésped Inmunocomprometido , Pronóstico , Sarcoma de Kaposi/patología , Sarcoma de Kaposi/virología , Neoplasias Cutáneas/patología , Neoplasias Cutáneas/virologíaRESUMEN
The authors report the case of a 27 years old athletic patient, without any antecedents, presenting with a recent complete atrioventricular (AV block, disclosed by an effort dyspnoea and syncope. The electrophysiological exploration showed a nodal AV block. The magnetic resonance imaging revealed the existence of a septal hypersignal in T1 mode enhanced after Gadolinium injection, and left ventricular function normality. It also revealed the existence of a pulmonary parenchyma infiltrate, confirmed by thoracic scanner. Pathological examination of transbronchial biopsies showed noncaseating granuloma, consistent with sarcoidosis. Programmed electrical stimulation induced no ventricular arrhythmia. A dual chamber pace-maker was implanted because of the AV block permanence and the poor clinical tolerance, associated with steroid therapy (prednisolone 1 mg/kg/j). After a 18 months follow-up, the patient remains asymptomatic, and the 12-lead ECG shows a normal AV conduction. The authors discuss the different aetiologies of AVB, and emphasize to realize an exhaustive assessment in young adults. The cardiac localization disclosing sarcoïdosis and the complete AV block disappearance under therapy make that observation original. The occurrence of a complete AV block complicating sarcoidosis poses a management and prognosis problem.
Asunto(s)
Cardiomiopatías/diagnóstico , Bloqueo Cardíaco/etiología , Sarcoidosis/diagnóstico , Adulto , Bloqueo Cardíaco/cirugía , Humanos , Masculino , Marcapaso ArtificialRESUMEN
This report describes a case of non-Hodgkin's lymphoma in a 31-year-old patient in whom HIV infection was subsequently diagnosed. The woman consulted for epigastralgia. Her medical history included gastritis caused by Helicobacter pylori that was given specific treatment. Clinical examination demonstrated type III splenomegaly and blood film examination demonstrated hypochromic microcytic anemia and neutropenia. Outcome was rapidly fatal and the patient died before start up of anti-retroviral therapy. This case suggests that a possible link between HIV and/or Helicobacter pylori and lymphomagenesis.
Asunto(s)
Infecciones por VIH/diagnóstico , Linfoma de Células B/diagnóstico , Linfoma de Células B Grandes Difuso/diagnóstico , Adulto , Resultado Fatal , Femenino , Gastritis/microbiología , Infecciones por Helicobacter/complicaciones , Helicobacter pylori , HumanosRESUMEN
The purpose of this retrospective analysis was to evaluate the outcome of pentamidine isethionate treatment (4 mg/kg of Pentamidine by the intramuscular route on Days 1 and 3) of cutaneous leishmaniasis in 326 cases that occurred during an outbreak among French military personnel in French Guyana from 1998 to 1999. A great difference was found between the 205 patients treated in French Guyana (series G) and 32 patients treated at the Laveran Military Hospital in Marseille, France (series L). Failure rate, i.e. 25% in series L versus 5% in series G, was significantly correlated with the delay to treatment which was much longer in series L. Extensive rhabdomyolysis was observed in all cases tested: this side-effect has not been reported. Based on these findings and a review of the literature on pentamidine isethionate, the authors recommend prompt treatment using lower doses. Other treatment alternatives for American cutaneous leishmaniasis are also presented including two of the latest developments in the field, i.e., oral treatment using miltefosine and topical treatment using agents such as paromomycine.
Asunto(s)
Antiprotozoarios/administración & dosificación , Leishmaniasis Cutánea/tratamiento farmacológico , Pentamidina/administración & dosificación , Antiprotozoarios/efectos adversos , Francia/etnología , Guyana Francesa , Humanos , Inyecciones Intramusculares , Personal Militar , Pentamidina/efectos adversos , Estudios Retrospectivos , Rabdomiólisis/inducido químicamente , Resultado del TratamientoRESUMEN
This richly illustrated article (80 color photographs) based on the authors' experience in French Guyana documents the clinical diversity of American tegumentary leishmaniasis. Main highlights include the often outstanding aspect of lesions, the high frequency of forms not associated with ulceration or scab formation that must be recognized to achieve diagnosis in travellers returning from endemic zones, and the special prognosis of clinical forms associated with intradermic, lymphatic or hematogenous spread. The article also reviews an original diagnostic method based on culture of cutaneous biopsy specimens on specific nutrient mediums that provides isolates in a high percentage of cases (80%) and thus allows identification of offending parasite.
Asunto(s)
Leishmaniasis Cutánea/patología , Humanos , Leishmaniasis Cutánea/fisiopatologíaRESUMEN
Primary extranodal malignant lymphoma is relatively rare. Clinical and radiological features may lead to the misdiagnosis of chronic osteomyelitis. We report a case of primary non-Hodgkin's lymphoma that involved the mandibular region in a 53-year-old man. Differential diagnosis with other mandibular diseases is difficult because there is a non specific clinico-radiological features and the difficulty of histologic interpretation. This pathology is important to recognize because of specific treatment. Global prognosis is relatively favorable if the lesion is localized.
Asunto(s)
Linfoma de Células B/diagnóstico , Neoplasias Mandibulares/diagnóstico , Biopsia , Diagnóstico Diferencial , Humanos , Inmunohistoquímica , Imagen por Resonancia Magnética , Masculino , Neoplasias Mandibulares/patología , Neoplasias Mandibulares/cirugía , Persona de Mediana Edad , Pronóstico , Tomografía Computarizada por Rayos XRESUMEN
The behavior of chromosomal inversions in Escherichia coli depends upon the region they affect. Regions flanking the replication terminus have been termed nondivisible zones (NDZ) because inversions ending in the region were either deleterious or not feasible. This regional phenomenon is further analyzed here. Thirty segments distributed between 23 and 29 min on the chromosome map have been submitted to an inversion test. Twenty-five segments either became deleterious when inverted or were noninvertible, but five segments tolerated inversion. The involvement of polar replication pause sites in this distribution was investigated. The results suggest that the Tus/pause site system may forbid some inversion events, but that other constraints to inversion, unrelated to this system, exist. Our current model for deleterious inversions is that the segments involved carry polar sequences acting in concert with other polar sequences located outside the segments. The observed patchwork of refractory and tolerant segments supports the existence of several NDZs in the 23- to 29-min region. Microscopic observations revealed that deleterious inversions are associated with high frequencies of abnormal nucleoid structure and distribution. Combined with other information, the data suggest that NDZs participate in the organization of the terminal domain of the nucleoid.
Asunto(s)
Inversión Cromosómica , Escherichia coli/genética , Genoma Bacteriano , MutagénesisRESUMEN
The yellow nail syndrome, a combination of yellow discoloured nails, lymphedema and pleural effusions, is a rare clinical condition. We report a case of the yellow nail syndrome associated with intestinal lymphangiectasia revealed by chylous ascites and protein-losing gastroenteropathy. This association reported in only three cases in the literature leads us to discuss the relations between yellow nail syndrome, primitive intestinal lymphangiectasia and primary lymphatic disorders.
Asunto(s)
Linfangiectasia Intestinal/complicaciones , Enfermedades de la Uña/complicaciones , Anciano , Ascitis Quilosa , Humanos , Linfedema/complicaciones , Masculino , Pigmentación , Derrame Pleural , SíndromeRESUMEN
The bisZ gene of Escherichia coli was previously described as encoding a minor biotin sulfoxide (BSO) reductase in addition to the main cytoplasmic BSO reductase, BisC. In this study, bisZ has been renamed torZ based on the findings that (i) the torZ gene product, TorZ, is able to reduce trimethylamine N-oxide (TMAO) more efficiently than BSO; (ii) although TorZ is more homologous to BisC than to the TMAO reductase TorA (63 and 42% identity, respectively), it is located mainly in the periplasm as is TorA; (iii) torZ belongs to the torYZ operon, and the first gene, torY (formerly yecK), encodes a pentahemic c-type cytochrome homologous to the TorC cytochrome of the TorCAD respiratory system. Furthermore, the torYZ operon encodes a third TMAO respiratory system, with catalytic properties that are clearly different from those of the TorCAD and the DmsABC systems. The torYZ and the torCAD operons may have diverged from a common ancestor, but, surprisingly, no torD homologue is found in the sequences around torYZ. Moreover, the torYZ operon is expressed at very low levels under the conditions tested, and, in contrast to torCAD, it is not induced by TMAO or dimethyl sulfoxide.
Asunto(s)
Escherichia coli/enzimología , Escherichia coli/genética , NADH NADPH Oxidorreductasas/genética , Operón , Oxidorreductasas N-Desmetilantes/genética , Oxidorreductasas/genética , Secuencia de Aminoácidos , Anaerobiosis , Mapeo Cromosómico , Escherichia coli/crecimiento & desarrollo , Isoenzimas/genética , Isoenzimas/aislamiento & purificación , Isoenzimas/metabolismo , Cinética , Datos de Secuencia Molecular , NADH NADPH Oxidorreductasas/aislamiento & purificación , NADH NADPH Oxidorreductasas/metabolismo , Oxidorreductasas/aislamiento & purificación , Oxidorreductasas/metabolismo , Oxidorreductasas actuantes sobre Donantes de Grupo CH-NH , Oxidorreductasas N-Desmetilantes/aislamiento & purificación , Oxidorreductasas N-Desmetilantes/metabolismo , Plásmidos , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Alineación de Secuencia , Homología de Secuencia de AminoácidoRESUMEN
Primary renal non-Hodgkin's lymphoma (NHL) is unusual, in contrast to the frequent renal involvement in disseminated NHL. We report a case of follicular lymphoma presenting initially as a renal mass. In the literature, twenty-seven similar cases have been described since 1980. The median age at diagnosis is 64 years with a male predominance. Clinical and radiological findings generally evoke renal carcinoma. Histologically, tumors are usually large B-cell lymphomas. The existence of renal non-Hodgkin lymphoma mimicking renal carcinoma must be recognized. Such lymphomas can either be primitive or be nodal with a renal presentation. Nephrectomy followed by chemotherapy permits long disease free survival.
Asunto(s)
Neoplasias Renales , Linfoma Folicular/diagnóstico , Anciano , Anciano de 80 o más Años , Antineoplásicos/uso terapéutico , Diagnóstico Diferencial , Humanos , Linfoma Folicular/patología , Linfoma Folicular/terapia , Nefrectomía , Tomografía Computarizada por Rayos XRESUMEN
A prophage lambda inserted by homologous recombination near dif, the chromosome dimer resolution site of Escherichia coli, is excised at a frequency that depends on its orientation with respect to dif. In wild-type cells, terminal hyper- (TH) recombination is prophage specific and undetectable by a test involving deletion of chromosomal segments between repeats identical to those used for prophage insertion. TH recombination is, however, detected in both excision and deletion assays when Deltadif, xerC, or ftsK mutations inhibit dimer resolution: lack of specialized resolution apparently results in recombinogenic lesions near dif. We also observed that the presence near dif of the prophage, in the orientation causing TH recombination, inhibits dif resolution activity. By its recombinogenic effect, this inhibition explains the enhanced prophage excision in wild-type cells. The primary effect of the prophage is probably an alteration of the dimer resolution regional control, which requires that dif is flanked by suitably oriented (polarized) stretches of DNA. Our model postulates that the prophage inserted near dif in the deleterious orientation disturbs chromosome polarization on the side of the site where it is integrated, because lambda DNA, like the chromosome, is polarized by sequence elements. Candidate sequences are oligomers that display skewed distributions on each oriC-dif chromosome arm and on lambda DNA.
Asunto(s)
Bacteriófago lambda/fisiología , Cromosomas Bacterianos , Escherichia coli/genética , Recombinación Genética/fisiología , Dimerización , Eliminación de SecuenciaRESUMEN
In Escherichia coli and Bacillus subtilis, long leader sequences are found upstream of the lysC coding sequences which encode lysine-sensitive aspartokinase. Highly conserved regions exist between these sequences. Mutations leading to constitutive expression of the E. coli lysC gene have been localised within these conserved regions, indicating that they participate in the lysine-mediated repression mechanism of lysC expression.
Asunto(s)
Aspartato Quinasa/genética , Escherichia coli/genética , Secuencias Reguladoras de Ácidos Nucleicos , Aspartato Quinasa/biosíntesis , Secuencia de Bases , Escherichia coli/enzimología , Regulación Bacteriana de la Expresión Génica , Genes Bacterianos , Datos de Secuencia Molecular , Homología de Secuencia de Ácido NucleicoRESUMEN
The propensity of the terminus of the Escherichia coli chromosome for recombination has been further explored, using a test based on the selectable loss of a lambda prophage inserted between repeated sequences from Tn10. Terminal recombination appears region-specific and unrelated to replication termination in a strain harboring a major chromosomal rearrangement. It requires RecBC(D) activity and must therefore occur between sister chromosomes, to conserve genomic integrity in spite of DNA degradation by RecBCD. Terminal recombination is maximal in the dif region and its intensity on either side of this recombination site depends on the orientation of the repeated sequences, probably because of the single chi site present in each repeat. Additional observations support the model that the crossover is initiated by single-strand invasion between sister chromosomes followed by RecBCD action as a consequence of DNA breakage due to the initial invasion event. Crossover location within repeats inserted at dif position supports the possibility that sister chromosomes are tightly paired in the centre of the terminal recombination zone. These data reinforce the model that postreplicative reconstruction of nucleoid organization creates a localized synapsis between the termini of sister chromosomes.
Asunto(s)
Proteínas de Escherichia coli , Escherichia coli/genética , Recombinación Genética , Cromosomas Bacterianos , Replicación del ADN , ADN Bacteriano/genética , ADN Bacteriano/metabolismo , Escherichia coli/metabolismo , Exodesoxirribonucleasa V , Exodesoxirribonucleasas/metabolismo , Secuencias Repetitivas de Ácidos NucleicosRESUMEN
The recombination site dif is the target on the Escherichia coli chromosome of the site-specific recombinases XerC and XerD. The dif/XerC-D system plays a role during the cell cycle, probably by favoring sister chromosome monomerization or separation. A phenomenon of regional control over dif activity, also analyzed in this issue, is demonstrated here by translocation of dif to a series of loci close to the normal locus. We found that the site is physiologically active only within a narrow zone around its natural position. Competence for dif activity does not depend on the sequence of the normal dif activity zone (DAZ), because delta(dif) deletions larger than the DAZ result in Dif+ bacteria when dif is reinserted at the junction point. Although dif maps where replication normally terminates, termination of replication is not the elicitor. A strain with a large inversion that places dif and its surrounding region close to oriC remains Dif+, even when a Tus- mutation allows replication to terminate far away from it. Preliminary data suggest the possibility that specialized sequences separate the competent zone from the rest of the chromosome. We suspect that these sequences are members of a set of sequences involved in a polarized process of postreplicative reconstruction of the nucleoid structure. We propose that this reconstruction forces catenation links between sister chromosomes to accumulate within the DAZ, where they eventually favor recombination at dif.
Asunto(s)
Cromosomas Bacterianos , Escherichia coli/genética , Recombinación Genética/genética , Inversión Cromosómica , Replicación del ADN/genética , Plásmidos/genética , Origen de Réplica/genética , Eliminación de Secuencia , Transformación Bacteriana/genéticaRESUMEN
The relationship between genes and enzymes in the methionine biosynthetic pathway has been studied in Pseudomonas aeruginosa. The first step is catalysed by an O-succinylhomoserine synthase, the product of the metA gene mapped at 20 min on the chromosome. The second step is achieved by direct sulfhydrylation, involving the enzyme encoded by a metZ gene that we have identified and sequenced, located at 40 min. Thus Pseudomonas appears to be the only organism so far described that uses O-succinylhomoserine as substrate for a direct sulfhydrylation. As in yeast, the two transsulfuration pathways between cysteine and homocysteine, with cystathionine as an intermediate, probably exist in parallel in this organism.
Asunto(s)
Liasas de Carbono-Oxígeno , Liasas/genética , Metionina/biosíntesis , Pseudomonas aeruginosa/genética , Secuencia de Aminoácidos , Secuencia de Bases , Prueba de Complementación Genética , Homoserina/análogos & derivados , Homoserina/metabolismo , Datos de Secuencia Molecular , Mutación , Pseudomonas aeruginosa/enzimología , Pseudomonas aeruginosa/crecimiento & desarrollo , Mapeo Restrictivo , Análisis de Secuencia de ADN , Homología de Secuencia de AminoácidoRESUMEN
The terminus region of the Escherichia coli chromosome is the scene of frequent homologous recombination. This can be demonstrated by formation of deletions between directly repeated sequences which flank a genetic marker whose loss can be easily detected. We report here that terminal recombination events are restricted to a relatively large terminal recombination zone (TRZ). On one side of the TRZ, the transition from the region with a high excision rate to the normal (low) excision rates of the rest of the chromosome occurs along a DNA stretch of less than 1 min. No specific border of this domain has been defined. To identify factors inducing terminal recombination, we examined its relation to two other phenomena affecting the same region, site-specific recombination at the dif locus and site-specific replication pausing. Both the location and the efficiency of terminal recombination remained unchanged after inactivation of the dif-specific recombination system. Similarly, inactivation of site-specific replication pausing or displacement of the replication fork trap so that termination occurs about 200 kb away from the normal region had no clear effect on this phenomenon. Therefore, terminal recombination is not a direct consequence of either dif-specific recombination or replication termination. Furthermore, deletions encompassing the wild-type TRZ do not eliminate hyperrecombination. Terminal recombination therefore cannot be attributed to the activity of some unique sequence of the region. A possible explanation of terminal hyperrecombination involves nucleoid organization and its remodeling after replication: we propose that post replicative reconstruction of the nucleoid organization results in a displacement of the catenation links between sister chromosomes to the last chromosomal domain to be rebuilt. Unrelated to replication termination, this process would facilitate interactions between the catenated molecules and would make the domain highly susceptible to recombination between sister chromosomes.
Asunto(s)
Cromosomas Bacterianos , Replicación del ADN , Proteínas de Escherichia coli , Escherichia coli/genética , Integrasas , Recombinación Genética , Proteínas Bacterianas/genética , Secuencia de Bases , Mapeo Cromosómico , Cromosomas Bacterianos/ultraestructura , Análisis Mutacional de ADN , ADN Nucleotidiltransferasas/genética , Modelos Genéticos , Datos de Secuencia Molecular , Recombinasas , Eliminación de SecuenciaRESUMEN
Plasmid pSC101 harbors a 28-bp sequence which is homologous to dif, the target site of the XerC/XerD-dependent recombination system in Escherichia coli. Using a technique which allows very sensitive detection of plasmid loss, we show that recombination at this site, termed psi for pSC101 stabilized inheritance, causes a moderate increase in pSC101 stability. The role of the psi sequence in site-specific recombination has been explored in two other contexts. It was cloned in a derivative of plasmid p15A and inserted into the chromosome in place of dif. In the first situation, psi activity requires accessory sequences and results in multimer resolution; in the second situation, it suppresses the effects of the dif deletion and can promote intermolecular exchanges. Thus, psi is a site whose recombinational activity depends on the context, the first in the cer/dif family known to exhibit such flexibility.