Integrating signals from T-cell receptor and serum by T cells enhance translation of tumour necrosis factor-alpha

Tumour necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine produced by several cell types, including T cells upon antigen stimulation. Its production is crucial for the development of an early defence against many pathogens, but its beneficial effects are dependent on the strength and duration of its expression. In this paper we present evidence indicating that serum increases translational efficiency of TNF-alpha in human peripheral blood mononuclear cells stimulated with superantigen. The increase in translation of TNF-alpha due to serum could be inhibited by the phosphatidylinositol (PI) 3-K inhibitors, wortmannin and LY294002, suggesting that PI 3-K is involved in the translational control of TNF-alpha by serum. Similarly to primary T cells, stimulation of Jurkat T cells with superantigen led to TNF-alpha secretion and this was up-regulated by serum. Transfection of Jurkat cells with a constitutively active form of PI 3-Kalpha increased the production of TNF-alpha in cells stimulated with superantigen. Additionally, we used the specific inhibitors targeting ERK kinase and p38 mitogen-activated protein kinase (MAPK), potentially downstream of PI 3-kinase, PD98059 and SB203580. Differently from with PI 3-K inhibitors, the accumulation of TNF-alpha mRNA was inhibited by PD98059 or SB203580. These results suggest that, in T cells, activation of PI 3-K is an important step in controlling TNF-alpha protein synthesis in response to growth factors.     

Molecular evolution of human immunodeficiency virus type 1 subtype A in Senegal: 1988-1997

OBJECTIVE: Few studies have been able to track the genetic diversity of HIV-1 viruses in human populations over time. We analyzed the molecular evolution of subtype A over a 10-year period, in a cohort of female sex workers with a known time of infection. STUDY DESIGN/METHODS: We amplified and sequenced the C2-V3 region of the surface envelope glycoprotein from 73 HIV-1-infected women, infected between 1987-1997. RESULTS: Fifty-one patients were infected by subtype A viruses. The viruses demonstrated significant diversification (p < 0.001) with mean genetic distance increasing from 8.6% in 1989 to 15.9% in 1997. The slope of the fitted curve suggested a rate of diversification of 0.7% per year. The majority of subtype A viruses clustered with HIV-1 subtype A/G recombinant form (IbNG). CONCLUSION: The genetic diversity of HIV-1 subtype A infections doubled over the first 10 years of this high risk population's epidemic, suggesting that implementation of vaccines early in the epidemic may have a higher likelihood of success based on levels of genetic diversity. The A/G recombinant form (IbNG) has taken epidemic proportions in West Africa. This is of particular importance in understanding the epidemiology of HIV-1 subtypes in Africa and to further dissect the potential phenotypic and biological characteristics of these viruses.     

Extended structural variation of a pentanucleotide repeat in the GSTP1 gene: characterisation in a normal population and in thyroid and gastric tumours

The promoter region of the human GSTP1 gene contains a polymorphic short tandem repeat (STR) locus consisting of pentanucleotide repeat units (ATAAA). In this work we report the existence of a total of 26 alleles in a Caucasian population. While differences in size (ranging from one to five base pairs) were responsible for the major variation, in five size-defined classes, two alternative sequences were found. Automatic fragment sizing and sequencing analysis revealed that this polymorphism is of a highly complex nature in contrast with previous reports. A genetic population study was carried out on a random sample from Portugal showing no deviation from Hardy-Weinberg equilibrium. Somatic instability studies were also performed on gastric and thyroid tumours using this STR: no instability was detected in thyroid tumour tissues when compared with their normal counterpart but in gastric tumour tissues microsatellite instability (MSI) was detected in 9.6% of the cases and loss of heterozygosity (LOH) also in 9.6% of the cases studied. The results obtained with GSTP1 in gastric cancer were compared with previously reported data on MSI using BAT-26 and several dinucleotide repeat markers.     

Interstitial telomeric DNA sequences of Chinese hamster cells are hypersensitive to nitric oxide damage, and DNA-PKcs has a specific local role in its repair

The DNA breakage detection-fluorescence in situ hybridization (DBD-FISH) procedure was used to analyze DNA single-strand breaks (SSBs) and alkali-labile sites induced by exposure to the nitric oxide (NO) donors sodium nitroprusside (SNP) and 3-morpholinosydnomine hydrochloride (SIN-1) in the whole genome and in long interstitial telomeric repeat sequence (ITRS) blocks from Chinese hamster cells. The relative density of DNA damage generated in the ITRS by X-rays was similar to that induced in the genome overall, whereas it was 1.7 times higher when the alkylating agent MNNG was assayed. Nevertheless, after SNP or SIN-1 treatment, ITRSs proved to be 2.8 and 2.7 times relatively more damaged, respectively, than the whole genome. When the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) was not active, as in XR-C1 mutant cells, the repair kinetics in the whole genome did not differ from that in the parental cell line with X-ray or SNP exposure. However, whereas the SSBs and alkali-labile sites induced in the ITRS by X-rays exhibited rejoining kinetics similar to that of the parental cell line, the damage induced by SNP was more slowly rejoined. This implies a role for DNA-PKcs in the repair of DNA damage induced by NO, especially in ITRSs. The results demonstrated intragenomic heterogeneity of NO-induced DNA damage and repair; there was a higher density of DNA damage in the ITRS blocks, possibly because of their guanine richness. This suggests that a parallel process may occur in the terminal telomeres, which has implications for premature aging and neoplastic development by chronic NO exposure in vivo.     

Kallikrein 4 expression is up-regulated in epithelial ovarian carcinoma cells in effusions

We immunohistochemically analyzed kallikrein 4 protein (hK4) expression in patients with epithelial ovarian carcinoma (181 malignant effusions and 103 solid carcinoma lesions). Expression of hK4 was also studied in 32 effusions using immunoblotting. Carcinoma cells expressed hK4 in 144 (79.6%) of 181 effusions and 85 (82.5%) of 103 solid tumors. Expression was seen in 51% or more of tumor cells in 70 effusions but often was limited to 5% or fewer cells in solid tumors (P = .009, primary tumors vs effusions; P = .002, metastases vs effusions). Immunoblotting showed hK4 expression in 31 of 32 specimens. Stromal cell hK4 expression, seen in 48 (46.6%) of 103 lesions, was significantly higher in primary tumors than metastases (26/43 vs 22/60, P = .019). hK4 expression in tumor cells was significantly lower in International Federation of Gynecology and Obstetrics stage IV than stage III tumors (P = .004, all lesions; P = .012, primary tumors). hK4 expression in carcinoma cells was associated with longer overall survival (not significant; P = .14, peritoneal effusions). hK4 is expressed widely in ovarian carcinoma; levels in carcinoma cells are highest in effusions, which might be related to loss of stromal contribution and/or altered microenvironment. hK4 expression in carcinoma cells of effusions or solid tumors does not predict survival.     

Novel autosomal recessive progressive hyperpigmentation syndrome

We present a family of Iraqui origin with three siblings affected by a novel type of progressive hyperpigmentation syndrome. The generalized initially diffuse, later disseminated hyperpigmentation started in early infancy and increased during childhood. It also affected palms and soles, and the face but spared the cheeks. Additional features were dry, itchy and sunlight sensitive skin, dystrophy of toe nails, hair loss, and myopia, but normal sweat glands. Light and electron microscopy showed signs of pigment incontinence and compound melanosomes as well as fibrillar bodies. The occurrence of this entity in affected siblings from a consanguineous mating suggests autosomal recessive inheritance. Extensive review of the literature showed no previous report with this distinct combination of clinical and microscopic findings.     

A novel 5q35.3 subtelomeric deletion syndrome

We observed a novel 3.5 Mb 5q subtelomeric deletion in a 3-year-old girl with developmental delay, hypotonia and multiple minor anomalies. Comparison of her phenotype with the few published patients with terminal 5q35 deletions revealed several overlapping features, but also showed remarkable differences such as shortness of stature versus macrosomia. After the report of 5q35.3 microdeletions in Sotos syndrome we integrated the published BACs into the public draft sequence and exactly mapped the deletion size in our patient by FISH analysis with 15 BAC probes. We demonstrated that the deletion in our patient is immediately adjacent to the reported Sotos syndrome deletion site. Subtracting the symptoms of Sotos syndrome from the published patients with larger 5q35.3 deletions allowed us to delineate a distinct phenotype of prenatal lymphedema with increased nuchal translucency, pronounced muscular hypotonia and delay of reaching motor milestones, but speech development within normal limits, wide fontanels, failure to thrive with postnatal short stature, and multiple minor anomalies such as mildly bell-shaped chest, minor congenital heart disease, and a distinct facial gestalt, associated with the novel 3.5 Mb cryptic deletion. We further showed in our patient that the deletion of the LCT(4) synthase gene results in a reduction of cysteinyl leukotriene synthesis to about 65% compared to normal values. The prenatal nuchal lymphedema associated with this deletion syndrome my be related to the deletion of the FLT4 gene causing autosomal dominant primary lymphedema and contributes to the differential diagnosis of increased fetal nuchal translucency.     

Hormonal responses to training and its tapering off in competitive swimmers: relationships with performance

During a winter training season, the effects of 12 weeks of intense training and 4 weeks of tapering off (taper) on plasma hormone concentrations and competition performance were investigated in a group of highly trained swimmers (n = 8). Blood samples were collected and the swimmers performed their speciality in competition at weeks 10 (mid-season), 22 (pre-taper) and 26 (post-taper). No statistically significant changes were observed in the concentrations of total testosterone (TT), non-sex hormone binding globulin-boundtestosterone (NSBT), cortisol (C), luteinising hormone, thyroid stimulating hormone, triiodothyronine, thyroxine plasma catecholamines, creatine kinase and ammonia during training and taper. Mid-season NSBT: C ratio and the amount of training were statistically related (r = 0.82,P < 0.05). Competition performance slightly declined during intense training [0.52 (SD 2.51) %, NS] and improved during taper [2.32 (SD 1.69)%,P < 0.01]. Changes in performance during training and taper correlated with changes in ratios TT: C (r = 0.86,P < 0.01andr = 0.81,P < 0.05, respectively) and NSBT: C (r = 0.77,P < 0.05 andr = 0.76,P < 0.05, respectively). In summary, these results showed that the monitored plasma hormones and metabolic indices were unaltered by 12 weeks of intense training and 4 weeks of taper. The TT: C and NSBT: C ratios, however, appeared to be effective markers of the swimmers' performance capacities throughout the training season.     

Effect of losartan on sodium appetite of hypothyroid rats subjected to water and sodium depletion and water, sodium and food deprivation

The involvement of angiotensin AT1 receptors in sodium appetite was studied in hypothyroid rats treated with the angiotensin II antagonist losartan. Losartan was administered chronically by the oral route or acutely by the subcutaneous route after water and sodium depletion or water, sodium and food deprivation. Three days after addition of losartan to the food at the dose of 1.0 mg x g(-1), the rats significantly reduced (P < 0.02) their spontaneous intake of 1.8% NaCl. Increasing the dose of losartan to 2.0 and 4.0 mg x g(-1) did not reduce NaCl intake; in contrast, the intensity of the sodium appetite gradually returned to previous levels. The simultaneous administration of captopril, an angiotensin converting enzyme inhibitor, and losartan significantly increased (P < 0.05) NaCl intake and after captopril removal NaCl intake returned to the levels observed with losartan treatment alone. The administration of losartan 4 days after the beginning of captopril treatment significantly reduced (P < 0.0001) NaCl intake. Following acute administration of losartan, water- and sodium-depleted rats significantly reduced their NaCl and water intake (P < 0.001). The administration of losartan also induced a significant reduction in NaCl and water intake in water, NaCl and food-deprived rats (P < 0.0001 and P < 0.001, respectively). The present results show that chronic treatment with oral losartan inhibited spontaneous sodium appetite in hypothyroid rats. Continuation of treatment rendered rats resistant to the blockade of AT1 receptors. Water and sodium depletion and water, NaCl and food deprivation induced sodium appetite, which in the short term depends on cerebral angiotensinergic activity mediated by the activation of AT1 receptors.