Role of intracellular second messengers and reactive oxygen species in the pathophysiology of V. cholera O139 treated rabbit ileum

Vibrio cholerae O139 has pandemic potential and it produces copious amounts of fluid secretion. The levels of various second messengers (intracellular Ca2+, cAMP, IP3, PKC) were measured to determine the cause of fluid secretion produced by this strain of V. cholerae. There was a significant increase in the levels of these second messengers in V. cholerae O139 treated ileum as compared to control ileum (enterocytes). Levels of these second messengers were also assessed in V. cholerae 569B induced fluid secretion in rabbit ileum and it was found that the levels were raised more in V. cholerae O139 treated ileum than in V. cholerae 569B treated rabbit ileum. The intestinal damage was assessed by measuring changes in the extent of lipid peroxidation of the enterocytes. Intracellular second messengers are known to raise the extent of lipid peroxidation. In V. cholerae O139 treated loops calcium ionophore A23187 enhanced the extent of lipid peroxidation whereas l-verapamil could only marginally decrease the lipid peroxidation. Dantrolene and H7 significantly decreased the extent of lipid peroxidation of enterocytes in V. cholerae O139 treated rabbit ileum. However, PMA could not enhance further the extent of lipid peroxidation in V. cholerae O139 treated rabbit ileum. So intracellular calcium and protein kinase C appear to be involved in intestinal damage caused by V. cholerae O139. Reactive oxygen species are responsible for causing tissue damage and the extent of oxidative damage depends on the balance between the pro-oxidants and the anti-oxidants. So the changes in the enterocytes' antioxidant level during V. cholerae O139 mediated intestinal infection was estimated. There was a significant decrease in the enterocyte level of the antioxidant enzymes SOD, catalase, glutathione peroxidase, glutathione reductase, glutathione transferase and glucose-6-phosphate dehydrogenase in V. cholerae O139 mediated intestinal infection. So a significant decrease in the levels of antioxidant defenses and a significant increase in the levels of second messengers appear to be important in mediating V. cholerae O139 induced lipid peroxidation which contributes to the changes in membrane permeability and thus to fluid secretion.

Prognostic significance of DNA ploidy and S-phase fraction in malignant serous cystadenocarcinoma of the ovary

OBJECTIVE

To determine the prognostic value of DNA ploidy and S-phase fraction in malignant serous cystadenocarcinoma of the ovary.

STUDY DESIGN

Flow cytometric analysis of nuclear DNA content was performed on paraffin-embedded tissues of 31 serous cystadenocarcinomas of the ovary. DNA ploidy, DNA index and S-phase fraction were determined without knowing the final outcome in the patients.

RESULTS

Histograms in 14 (46%) cases were aneuploid, whereas 17 (54%) were diploid. Aneuploidy was more frequent at the advanced stages of the disease as well as in the poorly differentiated histologic types. However, ploidy had a prognostic influence: both the disease-free survival and overall survival were better in diploid than aneuploid tumors at early and advanced stages. S-phase fraction (SPF) could be correctly assessed in 19 cases (62%) and was > 15% in 21% (4 cases). The survival of those patients, however, was not significantly different from that of those with SPF < 15%.

CONCLUSION

If used as an adjunct, DNA ploidy is of value in predicting tumor behavior, response to chemotherapy and disease recurrence.

Hypertension and insulin resistance in a native unindustrialised rural population of India

A cross-sectional survey of 2964 individuals aged 16-70 years from a rural area of North India was carried out to test the hypothesis that a rural unindustrialised hypertensive population of North India has central obesity and hyperinsulinemia. Oral glucose tolerance test was carried out on 68 newly detected hypertensives, 82 age- and sex-matched community controls and 58 genetically related members of hypertensives (family controls). Fasting blood samples were examined for plasma glucose, serum insulin and lipids. Postglucose-load blood samples were examined for plasma glucose and serum insulin. Three blood pressure readings were recorded using Random Zero Sphygmomanometer. Anthropometric measurements (waist-hip ratio, subscapular and triceps skinfold thickness) of all three groups of individuals (hypertensives, community controls and family controls) were also recorded. The hypertensives had significantly higher fasting and postglucose-load serum insulin levels (P<0.05), body mass index (21.3 vs. 19 kg/m2: P<0.05), waist-hip ratio (0.89 vs. 0.85: P<0.001), subscapular (18.5 mm vs. 12.7 mm: P<0.001) and triceps fold thickness (17.6 mm vs. 12.9 mm: P<0.05) than community controls. The family controls had significantly higher systolic blood pressure than community controls (P<0.05). The lipids were not significantly different in all the three groups. Multiple logistic regression showed that both fasting and postglucose-load serum insulin were significantly associated with hypertension independent of waist-hip ratio and body mass index. The results of the present study suggest that hyperinsulinemia is related to hypertension in a rural unindustrialised population of North India.

An easy method for detection of rheumatic antigen(s) in rheumatic fever/rheumatic heart disease patients by dot-ELISA

BACKGROUND

Various monoclonal antibodies developed against human B cell alloantigen have different positivity in different population groups around the world. Thus, monoclonal antibody D8/17, found to be 100% specific for rheumatic fever/rheumatic heart disease (RF/RHD) patients from New York, identified only 62% to 68% in the north Indian population.

PATIENTS AND METHODS

A battery of monoclonal antibodies against B cell alloantigen was developed in Indian RF/RHD patients. A total of 50 patients and 25 controls were studied.

RESULTS

These antibodies, named PG-12A, -13A and -20A, demonstrate more specificity in north Indian patients. In dot-ELISA, these antibodies correctly show the presence of the marker in 84% of RHD and 90% of recurrence of rheumatic activity patients.

CONCLUSIONS

It is suggested that different alloantigens are expressed in the north Indian population. This standardized dot-ELISA is low cost and simple to use, and has a very high percentage of sensitivity, specificity and positive predictive value for this population.

Role of reactive oxygen species in Salmonella typhimurium-induced enterocyte damage

BACKGROUND

Reactive oxygen species (ROS) are potent mediators of inflammatory cell-mediated tissue destruction and may be of pathophysiologic importance in Salmonella typhimurium-induced tissue damage.

METHODS

In this study the ligated rat ileal loops were injected with Salmonella live culture or toxin. The ROS generation was detected by measuring the mucosal myeloperoxidase (MPO) activity; the enterocyte xanthine oxidase (XO) activity, and the chemiluminescence response of gut macrophages. The enterocyte damage was estimated by measuring the extent of lipid peroxidation and cell viability.

RESULTS

Treatment with Salmonella live culture or toxin resulted in an increase in the mucosal MPO activity, the enterocyte XO activity, and the chemiluminescence response of macrophages. Treated loop enterocytes had an increased extent of lipid peroxidation and decreased cell viability. Cell viability was also decreased when the enterocytes were co-cultured with macrophages isolated from the treated loops. Lipid peroxidation decreased, and cell viability increased in the presence of superoxide dismutase (SOD) or catalase.

CONCLUSIONS

The S. typhimurium-mediated intestinal infection is accompanied by an increased generation of ROS, which may induce the lipid peroxidation of the enterocyte membrane, thereby leading to a loss of cell viability.

Ethnic differences in expression of susceptibility marker(s) in rheumatic fever/rheumatic heart disease patients

The ability of monoclonal antibodies (MAb) against a human B lymphocyte alloantigen has been suggested to discriminate between rheumatic fever "susceptible" individuals and persons with a lower risk of developing RF. However, while such MAb have been reported to identify a majority of RF/RHD patients in some populations, a reduced discriminatory ability has been observed in others. Antigenic variation in the RF marker(s) may exist among ethnic groups which reduce the discriminatory ability of these monoclonal antibodies. We developed MAb using B lymphocytes from RF patients of North Indian ethnic origin. In this same population we compared the new MAb (PGI/MN II) with a previously described MAb of Caucasian ethnic origin (D8/17). In three groups: acute rheumatic fever patients (no evidence of previous attacks of rheumatic fever), patients with chronic rheumatic heart disease and normal controls from the same population, we found a greater discriminating ability of PGI/MNII MAb to identify Indian RF/RHD patients than with the D8/17 MAb. Further, sixty percent of 142 siblings of the RF/RHD patients were "positive" when tested with PGI/MN II. The data from these studies suggest that before such MAb can be used for identification of RF "susceptibles" in public health programs, variation among ethnic populations must be assessed.

Endotoxemia predicts outcome in acute pancreatitis

The incidence of complications of acute pancreatitis is high in patients with endotoxemia, and so we determined the endotoxin levels in the blood and peritoneal fluid of patients with acute severe pancreatitis to correlate the levels with any sequelae. Fourteen patients with acute severe pancreatitis were examined with regard to clinical features, biochemical tests, and laparotomy (n = 9). In all coagulation profiles, blood gas analysis, chest and abdominal x-rays, ultrasound, and abdominal computed tomography scan (n = 10) were performed. Qualitative estimation of endotoxin levels was done in peripheral blood and peritoneal and peripancreatic fluid. Ten (71.42%) of 14 patients had endotoxin in the blood, and 9 (64.28%) had it in the peritoneal fluid. Twelve (85.7%) had pulmonary involvement, with hypoxia being the most common (85.7%); among them endotoxin was found in the blood of 10 (83.32%) and in the peritoneal fluid of 8 (66.66%) patients. Renal dysfunction was found in 4 (28.57%) patients; endotoxin was present in the blood of all 4 patients and in the peritoneal fluid of 3 (75%) patients. Cardiovascular abnormality was detected in 8 (57.14%) patients, and endotoxin was present in the blood and peritoneal fluid of all patients. Metabolic abnormality was present in 8 (57.14%) patients; endotoxin was present in the blood of all 8 patients and in the peritoneal fluid of 7 (87.6%) patients. Eight (88.88%) of the 9 patients who required surgery had endotoxemia. Three (30%) patients with endotoxemia survived, whereas all 4 patients without endotoxemia survived. Mean hospital stay was 61.2 days and 46.7 days for endotoxin-positive and endotoxin-negative patients, respectively. We conclude that the presence of endotoxin in blood and peritoneal fluid correlates with the severity, systemic complications, and mortality rates of acute pancreatitis. Endotoxin estimation can identify patients at risk in the early stages of acute pancreatitis.

Impairment of intestinal mucosal antioxidant defense system during Salmonella typhimurium infection

The mucosal pathology of Salmonella typhimurium infection may in part be due to the excessive production of reactive oxygen species (ROS). The influence of S. typhimurium infection on the intestinal mucosal antioxidant defense system was investigated. We injected ligated rat ileal loops with Salmonella live culture or toxin. After 18 hr of infection, the animals were killed and enterocytes isolated from the ileal loops. The enterocyte-reduced glutathione (GSH) content and activities of the enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase, glutathione-S-transferase (GST), glutathione reductase (GR), and glucose-6-phosphate dehydrogenase (G6PDH) were spectrophotometrically estimated. The vitamin E and A contents were determined by high-performance liquid chromatography (HPLC). In both the Salmonella live culture and toxin-treated groups, the enterocyte GSH and vitamin E contents and activities of the enzymes SOD, GSH-Px, catalase, GR, and G6PDH were significantly decreased as compared to the control group. However there was a significant increase in the enterocyte activity of GST. There was no change in the vitamin A content of the enterocytes. These findings might indicate a decreased endogenous intestinal protection against ROS in S. typhimurium-mediated infection, which could contribute to the pathogenesis of the disease.

Intestinal mucosal lipid peroxidation and absorptive function in Salmonella typhimurium mediated intestinal infection

S. typhimurium infection is associated with neutrophil infiltration within the intestinal mucosa. Neutrophil activation provides a major source of reactive oxygen species (ROS). The mucosal pathology of S. typhimurium infection may be in part due to the excessive production of these reactive species. This study was carried out to investigate if ROS play a role in mediating the changes in the structural components and functional properties of brush border membrane (BBM) in rats during S. typhimurium infection. This was done by determining the changes in the BBM extent of lipid peroxidation and absorptive function. A significant increase in the extent of lipid peroxidation of BBM during S. typhimurium infection was observed as judged by malondialdehyde (MDA) and conjugated diene formation and depletion of alpha-tocopherol and protein associated thiol groups. A significant decrease in the BBMV (brush border membrane vesicle) transport of amino acids was also observed. However there was no change in the transport of D-glucose. The decrease in amino acid transport further led to a significant decrease in the enterocyte level of protein synthesis. Exposure of BBMV to a free radical donor, cumene hydroperoxide, also led to an increase in the extent of lipid peroxidation and a decrease in the amino acid transport. Possibly ROS might play a significant role in mediating the mucosal damage during S. typhimurium infection.

Shigella dysenteriae type 1 toxin induced lipid peroxidation in enterocytes isolated from rabbit ileum

To evaluate the role of reactive oxygen species (ROS) in Shigella dysenteriae 1 toxin (STx) mediated intestinal infection, the ligated rabbit small intestinal loops were injected with STx. The enterocytes isolated from STx treated rabbit ileal loops had a significantly higher level of lipid peroxidation as compared to enterocytes isolated from control rabbit ileum. To study the role of second messengers in STx mediated intestinal damage, the in vivo and in vitro effects of modulators of lipid peroxidation of enterocytes were used. The presence of Ca2+-ionophore A23187 enhanced the extent of lipid peroxidation in enterocytes isolated from the control and STx treated rabbit ileum. However, 1-verapamil only marginally decreased the lipid peroxidation level of enterocytes isolated from STx treated rabbit ileum. The in vitro effect of modulators was in agreement with in vivo studies. Dantrolene significantly decreased the extent of lipid peroxidation of enterocytes isolated from STx treated rabbit ileum. PMA significantly increased the lipid peroxidation level of enterocytes isolated from control ileum. However, PMA could not further enhance the lipid peroxidation level of enterocytes isolated from STx treated rabbit ileum. The presence of H-7 significantly decreased the extent of lipid peroxidation of enterocytes isolated from STx treated rabbit ileum. In vitro effect of PMA and H-7 was in agreement with that of in vivo findings. The role of arachidonic acid metabolites, prostaglandins (PGs), in mediating STx induced lipid peroxidation was also studied. The presence of indomethacin (a PG synthesis inhibitor) significantly decreased the lipid peroxidation induced by STx. These findings suggest that lipid peroxidation induced by STx is mediated through cytosolic calcium. The increase in (Ca2+)i leads to activation of PKC. A significant decrease in the enterocyte levels of antioxidant enzymes superoxide dismutase, catalase and reduced glutathione in STx treated rabbit ileum as compared to control was seen. A significant decrease in vitamin E levels was also observed. This suggests that there is decreased endogenous intestinal protection against ROS in STx mediated intestinal infection which could contribute to enterocyte membrane damage that ultimately leads to changes in membrane permeability and thus to fluid secretion.

Red cell acetyl cholinesterase and plasma cholinesterase activity and genetic variants of plasma cholinesterase in northwest Indian adults

The plasma cholinesterase (PChE) and red cell acetyl cholinesterase (AChE) activities are indicators of exposure to organophosphates. We studied their distribution in unexposed Northwest Indian adults by measuring them in 120 men and 111 women by Ellman's and Kalow's method, respectively. We also determined genetic variability of plasma cholinesterase in 193 subjects (male = 111, female = 82). The mean +/- (SD) AChE levels in population, men and women, were 34.97 +/- 13.66, 35.05 +/- 12.42, 34.88 +/- 14.89 nmol/mg Hb/min, whereas PChE was 0.448 +/- 0.173, 0.435 +/- 0.163, 0.462 +/- 0.183 ku/l, respectively. When compared for sex, no significant difference could be found for red cell AChE and PChE activity. However, on 2-way analysis of variance (ANOVA) adjusted for age classification, the levels of both AChE and PChE were significantly higher in groups above the age of 30 years as compared to below 30 years (t = 3.08, p < 0.01, t = 2.82, p < 0.05), respectively. Seven genetic variants of PChE could be detected in males, whereas in females 6 genetic variants were found.

Role of iron and iron chelation therapy in oxygen free radical mediated tissue injury in an ascending mouse model of chronic pyelonephritis

The contribution of iron towards the free radical generation leading to renal tissue damage was assessed using a non-obstructive ascending mouse model for chronic pyelonephritis. The parameters studied include luminol dependent chemiluminescence (LDCL), histopathology and some biochemical investigations. We found that iron enhanced the renal tissue damage and led to renal scarring, and end point in chronic renal inflammation, irrespective of the bacterial strain studied. In addition a role of iron chelation therapy as a treatment for chronic renal inflammation is also suggested.

Biochemical changes induced by malarial parasites

The morbidity associated with malaria plays a key role in the staggering of the social and economic development of human race. The investigations on the cellular, biochemical and molecular organisation of the malarial parasite are important to understand the host parasite interactions in a better way. The parasite induces several biochemical and biophysical alterations in the host red cells. It is well recognized that cation homeostasis is vital to basic aspects of cell functions. Though the pathogenesis of anaemia associated with Plasmodium falciparum infection is multifactorial, the complex mechanisms involving the role of oxidant stress and calcium imbalance of infected red cells plays an important role.

Calcium and protein kinase C play a significant role in response to Shigella toxin in rabbit ileum both in vivo and in vitro

The role of second messengers in Shigella toxin (STx) induced fluid secretion in rabbit ileum was evaluated. In vivo and in vitro studies were carried out in presence or absence of following modulators: Ca2+ ionophore A23187 (15 microM), l-verapamil (200 microM), phorbol-12-myristate-13-acetate (PMA, 200 ng), 1-(5-isoquinolinyl-sulphonyl)-2-methyl-piperazine (H-7, 15 microg) and indomethacin (20 microM). In in vivo studies, the fluid accumulation into rabbit ileal loops in response to STx was measured in presence or absence of these modulators. In in vitro studies, unidirectional fluxes of Na+ and Cl- were carried out in presence or absence of these modulators. The addition of Ca2+ ionophore A23187 along with STx further increases the amount of fluid already induced by STx. Whereas the presence of l-verapamil along with STx did not decrease the amount of fluid induced by STx. In vitro findings were in consonance with the in vivo studies. A significant increase in inositol triphosphate (IP3) levels was observed in enterocytes isolated from STx treated rabbit ileum. The addition of PMA into rabbit ileal loops in presence of STx mimicked the effect of STx while the presence of H-7 reversed the secretion caused by STx to absorption. Similar results were obtained while determining unidirectional fluxes of Na+ and Cl- in presence of PMA and also with H-7. A significant increase in PKC levels was observed in the membrane fraction of enterocytes isolated from STx treated rabbit ileum as compared to control. Further a marked decrease in PKC levels was observed in the presence of H-7 in membrane fraction of enterocytes isolated from STx treated rabbit ileum. The addition of indomethacin into rabbit ileal loops reversed the secretion (caused by STx) to absorption. In vitro findings were in consonance with in vivo studies. Besides, there was a significant increase in PG-E levels in enterocytes isolated from STx treated rabbit ileum as compared to control. These findings suggested that STx induced enteritis involves the role of PKC, intracellular calcium stores and prostaglandins. The extracellular calcium pool probably does not play a significant role in this process.

Dynamics of conjunctival impression cytologic changes after vitamin A supplementation

To investigate the chronological changes in conjunctival epithelium after supplementation with a massive oral dose of vitamin A, conjunctival impression cytology (CIC) with transfer was carried out repeatedly among 200 children aged 6-120 months in a randomized, double-blind, placebo-controlled study in Chandigarh (India). Significant conversion to normal CIC started 71-80 d after vitamin A supplementation and by 101-110 d conversion had taken place in all children. Compared with the placebo group, plasma retinol concentration at 100 d post-supplement was found to be significantly higher in the vitamin A-supplemented group P = 0.04. This study demonstrates that CIC responds to a massive oral dose of vitamin A 3-4 months after supplementation. These findings should guide future studies and evaluations in which CIC is used to assess response to vitamin A interventions.

Role of type-1 fimbriae in the pathogenesis of chronic pyelonephritis in relation to reactive oxygen species

The role of type-1 fimbriae in the pathogenesis of chronic pyelonephritis was studied for two Escherichia coli strains. Although both strains produced a similar total oxidative burst of chemiluminescence in macrophages from uninfected mice, the extracellular oxidative burst was greater with the non-fimbriate mutant E. coli BH-5 than its type-1 fimbriate parent E. coli 31-B. Moreover, macrophages from mice infected with the non-fimbriate mutant gave a much greater oxidative burst when stimulated with latex particles than that given by macrophages from mice infected with the type-1 fimbriate parent. These results correlated with the degree of renal inflammation and scarring as measured by malondialdehyde formation. Hence, the role of type-1 fimbriae in the pathogenesis of chronic UTI although documented does not appear to be significant.

Compliance of secondary prophylaxis for controlling rheumatic fever and rheumatic heart disease in a rural area of northern India

This study was conducted in a community development block of a district in Haryana to evaluate the compliance of secondary prophylaxis for controlling rheumatic fever (RF) and rheumatic heart disease (RHD). The patients were interviewed using a semi-structured schedule at home. Currently 110 patients are registered in RF/RHD registry of which 53 (48.2%) are males. Mean age of patients was 18.4 +/- 8.6 years, ranging from 6 to 50 years with majority (48, 43.7%) of patients in the age groups of 6-15 and 16-25 years. Out of 110 patients, more than 90 percent had taken 11 out of the 12 due doses of secondary prophylaxis every year in the last eight years of the programme except in 1995 when 92 (83.6%) patients took the prophylactic doses. Only one patient reported recurrent attacks of rheumatic fever after irregular secondary prophylaxis. Eighteen (16.4%) patients were defaulters at the time of interview and were motivated to take secondary prophylaxis regularly. Ninety-seven (88.2%) patients were satisfied with the ongoing programme. In developing countries, it is possible to successfully apply a secondary prevention programme for control of RF/RHD by using existing health infrastructure.

Increasing toxoplasma seropositivity in women with bad obstetric history and in newborns

BACKGROUND

Most infants with congenital Toxoplasma gondii infection have no symptoms at birth but few may develop retinal diseases or neurological abnormalities later in life. The presence of significant titres of antitoxoplasma antibodies in women in the reproductive age group indirectly indicates that Toxoplasma gondii is the cause of such congenital abnormalities and also sporadic abortions in some women.

METHODS

We did a retrospective analysis of antitoxoplasma antibodies detected by indirect haemagglutination assay, in women with bad obstetrical history and in newborns clinically suspected of congenital toxoplasmosis during 1981-91.

RESULTS

A significant increase in seropositivity in women and newborns was seen during 1989-91 as compared to 1981-88. More seropositive patients were recorded between April-June and October-December. However, no significant correlation could be observed between rising incidence of seropositivity and the seasonal distribution or age of women.

CONCLUSION

Epidemiological studies are required to ascertain the reason for the increasing trend of toxoplasma seropositivity and to suggest appropriate control strategies as it is possible to prevent congenital infection.

TH1 pattern of cytokine secretion by splenic cells from pyelonephritic mice after in-vitro stimulation with hsp-65 of Escherichia coli

Splenic lymphocytes and peritoneal macrophages from BALB/c mice with Escherichia coli pyelonephritis were obtained at various intervals after infection. These cells were stimulated in vitro with different antigens and cytokine release was assayed in the supernate of the cultured cells. It was observed that both specific antigens such as outer-membrane proteins (OMPs), porins and heat-shock protein-65 (hsp-65), as well as non-specific mitogens such as phytohaemagglutinin (PHA), were able to induce cytokine production by splenic cells from infected mice. Of all these antigens, hsp-65 was found to be the best inducer of cytokine release. In the acute stage of pyelonephritis, the release of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) was found to increase with time; both reached their peak values on the seventh day after infection. The TH1 pattern of cytokine secretion by splenic cells was observed, i.e., IL-2 and IFN-gamma, whereas there was complete absence of IL-4 secretion. In the chronic stage of pyelonephritis, i.e., 150 days after infection, a decrease in the level of IL-2 and IFN-gamma was observed. Peritoneal macrophages released IL-1 on stimulation with hsp-65, which increased with the progression of disease. The possible implications of this study for the disease process are discussed.

Antigenic differences between axenic amastigotes & promastigotes of Leishmania donovani

The axenic amastigotes of an Indian strain of L. donovani have been generated from the promastigote form at 37 degrees C in RPMI-1640 medium, pH 6.0 +/- 0.5, supplemented with 10 per cent heat inactivated foetal calf serum and these are being maintained through serial subculturing under the same conditions. The present study was carried out to differentiate axenic amastigote from the promastigote stage on the basis of their antigenic constitution and also to look for any immunoreactive antigen(s) specific to axenic amastigotes. SDS-PAGE analysis revealed a few stage specific and some conserved antigenic fractions in both the stages. On immunoblotting with immune sera raised against the membrane fractions of the axenic amastigotes, the 200 kDa antigenic fraction of axenic amastigote was found to be highly reactive. When the immune sera raised against the membranes of both stages were checked by immunofluorescence no cross reactivity was observed at higher dilutions. These findings showed that there are some antigenic diversities as well as similarities between the two stages of L. donovani cultured in vitro. Also, the 200 kD fraction of axenic amastigote appeared to be an immunodominant antigen specific to that stage.

A flowcytometric study of CD4+ & CD19+ cell lymphopenia in patients with alopecia areata

Twenty five patients with alopecia areata and 20 healthy controls were studied by flowcytometry employing direct two colour immunofluorescence in erythrocyte lysed whole blood. A significant reduction was observed in helper/inducer (CD4+) lymphocytes (29.4 +/- 7.4 vs 39.45 +/- 8.0, P < 0.01) and B (CD 19+) lymphocytes (11.04 +/- 6.57 vs 15.0 +/- 5.05, P < 0.01) in comparison with healthy controls. Decrease in T-lymphocytes (CD3+) and suppressor/cytotoxic (CD8+) was not significant and activated (HLADR+) lymphocytes and natural killer cells (CD16+ and CD56+) were within normal limits. Our findings suggest a significant T helper (CD4+) and B (CD19+) cell lymphopenia in alopecia areata.

Plasma reactive nitrogen intermediate levels in patients with clinically active rheumatoid arthritis

We studied reactive nitrogen intermediate levels in 31 patients with active rheumatoid arthritis (RA) taking indomethacin and 20 healthy controls using nitrite and citrulline levels, measured by spectrophotometry, as markers. Twenty patients with RA were followed up after 4 and 8 wk of treatment with additional therapy in the form of methotrexate. Mean nitrite levels in 31 patients were 0.94 +/- 0.41 mumol/ml and 20 controls it was 1.18 +/- 0.99. After treatment with methotrexate for 4 and 8 wk the levels were 0.9 +/- 0.45 and 1.25 +/- 1.15 mumol/ml, respectively. Mean citrulline levels in all patients was 1.68 +/- 0.11 and controls was 1.39 +/- 0.6 mumol/ml. Following therapy with methotrexate for 4 and 8 wk the levels were 1.40 +/- 0.49 and 1.40 +/- 0.51 mumol/ml, respectively. It is possible that serum levels of these products may not reflect alterations in the synovial fluid levels. Alternatively, whatever lowering may have been achieved by the anti-inflammatory effect of the therapy may have been countered by drug derived free radicals.