Beyond survival: unraveling the adaptive mechanisms of cucurbit weeds to salt and heavy metal stress through biochemical and physiological analyses

Salt stress and heavy metal are instigating hazard to crops, menace to agricultural practices. Single and combined stresses affecting adversely to the growth and metabolism of plants. To explore salt and heavy metal resistant plant lines as phytoremediants is a need of time. Physiological responses are main adaptive responses of the plants towards stresses. This response varies with species and ecotype as well as type and level of stress. Two cucurbit weeds from two ecotypes were selected to evaluate their physiological adaptations against independent and combined stresses of various levels of salt (NaCl) and heavy metal (NiCl2). Various physiological parameters like water potential, osmotic potential, pressure potential, CO2 assimilation rate, stomatal conductance, chlorophyll a and b, carotenoids, and production of adaptive chemicals like SOD, CAT, proteins, sugars and proline were studied. Citrullus colocynthis showed more adaptive response than Cucumis melo agrestis and desert ecotype was more successful than agricultural ecotype against stresses.

Electrochemical regeneration of hexavalent chromium from aqueous solutions in a gas sparged parallel plate reactor

In this study anodic oxidation of Cr₂(SO₄)₃ was carried out in an air-sparged divided parallel plate cell. Variables studied were current density, Cr₂(SO₄)₃ concentration, and superficial air velocity. The rate constant of Cr₂(SO₄)₃ oxidation was found to increase with increasing current density and Cr₂(SO₄)₃ concentration. The effect of air sparging was found to depend on Cr₂(SO₄)₃ concentrations, at high Cr₂(SO₄)₃ concentration (> 0.1 M) air sparging does not affect the rate constant of the reaction denoting that the reaction is charge transfer controlled. As Cr₂(SO₄)₃ concentration decreases below 0.1 M the reaction becomes under mixed diffusion and chemical control and the rate constant increases with increasing air superficial velocity, the lower Cr₂(SO₄)₃ concentration the higher the contribution of diffusion to the reaction rate. The current efficiency of the process ranged from 20 to 85% depending on current density and Cr₂(SO₄)₃ concentration. Electrical energy consumption which ranged from 1.8 to 14.4 kW h/kg of Cr⁶⁺ was found to increase with increasing current density and decreases with increasing Cr₂(SO₄)₃ concentration. Air sparging was found to decrease electrical energy consumption in the case of dilute solutions << 0.1 M Cr₂(SO₄)₃.

MO537INTERACTION OF PLASMA HOMOCYSTIENE, RENAL FUNCTION AND CARDIO-METABOLIC RISK FACTORS- AN OBSERVATION IN A RURAL POPULATION OF BANGLADESH

Background and Aims

Elevated plasma total homocystiene (tHcy) levels are associated with atherosclerotic diseases in coronary, cerebral and peripheral blood vessels. It is possible that hyperhomocysteinemia may lead to intrarenal arteriosclerotic lesions and decline in GFR or impaired renal function. Aim of this study was to elucidate the association of plasma homocystiene level with renal function and cardiovascular risk factors in rural population.

Method

A well defined rural area was selected. Study subjects were identified by computer generated random numbers after entering household listings and then Kish table was used to choose a participant. Adult subjects (≥18 years) were only included. The approached participant was explained the purpose, if consented, then given an appointment to be present at a research hospital on a separate date for clinical and biochemical evaluation. A face to face interview was conducted. Clinical history, physical examination anthropometrics were recorded on data sheet. Fasting blood sample and morning spot urine was collected. Then serum tHcy was measured by chemiluminescent microparticle immunoassay (CMIA) technology. Study population were investigated with Spot urine ACR, Fasting glucose, serum lipid profile, creatinine, homocysteinine , Folic acid and Vit B12.

Results

Early results of 234 random subjects are presented here. The mean age was 41 ± 13(18-92) years with male 33% and female 67%. Mean eGFR was 99± 26 ml/min, tHcy 11.6 ± 5.9 μmol/l, Vit B12 329 ± 187 pg/ml and Folic Acid 5.57 ± 2.63 ng/ml. A tHcy cut-off value in study subjects ≥15 μmol/l was seen in 17 % and &lt;15 μmol/l in 83%. Serum creatinine, Uric Acid, Cholesterol, LDL was significantly higher and Vit B12, Folic acid lower in tHcy ≥15 μmol/l group. Further grouping showed tHcy level was significantly higher in Vit B12&lt;200 pg/ml and Folic acid &lt;3ng/l group. Correlation studies showed homocystiene positively correlated with age, systolic blood pressure, creatinine, LDL and negatively with Folic acid and Vit B12.

Conclusion

Our findings suggest that elevated plasma homocystiene level might influence and are associated with altered markers of renal, cardiac and metabolic risk factors in rural population. Preventive approaches are required towards this issue as larger population segment belongs to rural areas.

MO111PATTERN OF CARDIAC AND RENAL RISK FACTORS PREVAILING IN HYPERTENSIVE SUBJECTS OF RURAL COMMUNITY: PRIMARY RESULTS FROM AN ONGOING SYSTEMATIC SURVEY IN BANGLADESH

Background and Aims

Hypertension is the leading entity of non communicable diseases (NCD). Some 15-30% adult population is identified suffering from hypertension at any given time worldwide. Complications of hypertension cause severe functional deficit and a major decline in quality of life for the patient and family.

This study was carried out to identify the presence and pattern of cardiac and renal risk factors influencing major morbidity and mortality in hypertensive subject by performing relevant clinical and laboratory evaluations.

Method

In this survey adult subjects were selected randomly from a defined rural area. Their demographic, anthropometric and clinical information was recorded by WHO STEP wise approach surveillance-Instrument v.3.1. Information on prevailing NCDs and related risk factor were collected on a short questionnaire by face-to-face interview. Blood Pressure (BP) was measured by digital blood pressure monitor (Omron) with standard sized cuff after 10-15 minutes of rest in sitting posture by taking mean of two readings. Systolic BP ≥140 and/or diastolic BP ≥90mmHg or subjects taking antihypertensive medications were considered for hypertension. Early morning urine and fasting blood sample was collected for glycemic profile, lipid profile, serum creatinine, eGFR (MDRD equation) and urine ACR estimations for identifying diabetes, dyslipidemia and nephropathy. Results from an early group are presented here.

Results

From surveyed population consequative 300 hypertensive subjects with 100 normotensive subjects were analyzed. Male/female distribution was 66% and 34%. Age in 75% was between 25-55 years and BMI overweight to obese in 45%. Etiology wise in 81% it was essential hypertension followed by diabetes 18% and nephropathies in rest. Mean systolic BP was 147±16 and diastolic BP 71±9 mmHg. Comparison of hypertensive vs. normotensives showed FBS 6.7±3 vs. 5.8±1.0 mmol/l, (p&lt;0.001). Lipids as cardiac markers were TG 170±107 vs. 130±76 g/dl, (p&lt;0.001); Cholesterol 195±50 vs. 180±49 g/dl, (p&lt;0.001); LDL 170±107 vs. 130±76 g/dl, (p&lt;0.04); and HDL 42±7 vs. 46±8 g/dl, (p&lt;0.001). Renal parameters like eGFR was 88±22 vs. 98±26 ml/min, (p&lt;0.001); and ACR 99±556 vs. 30±87 mg/g, (p&lt;0.04). These comparisons showed fasting hyperglycemia with most of the lipids higher and HDL lower in hypertensives. Renal parameters like eGFR was lower and albuminuria was significantly higher with similar urinary Na and K excretion in hypertensives. Other cardio renal markers like Uric Acid and hCRP was similar in both groups. Pearson’s correlations showed a positive correlation of systolic and diastolic BP with major components of cardiac, renal and metabolic risk factors.

Conclusion

It is found that hypertension is essential in nature among 81% of rural subjects. Nearly half of the study subjects are overweight. Dyslipidemia, albuminuria and low GFR is more pronounced in hypertensives in comparison to the normotensive counterparts. So, hypertension is mostly associated with adverse cardio-renal risk markers.

Influence of probiotic and yeast culture supplementation on selected biochemical and immunological parameters of growing lambs

This study was carried out to evaluate the potential effects of 90 days-long dietary supple- mentation of probiotic and yeast culture on immunity condition of lambs. Fifteen Rahmani growing male lambs (about 5 months old and 23.21±2.75 kg body weight) were randomly allo- cated to three equal groups consisting of 5 animals each. The animals in the first group, served as a control (group C), were fed a basal diet without any supplementation. The lambs in the second and third group were fed the basal diet supplemented with probiotic (group Y) or yeast culture (group YC), respectively. The probiotic consisted of live yeast (Saccharomyces cerevisae) alone, while the yeast culture was composed of Saccharomyces cerevisiae and the media on which it was grown. In group Y and YC, each lamb was supplemented daily with 0.5 g and 7.0 g of live yeast and yeast culture, respectively. Blood samples were collected before feeding the supplements and then every 15 days until the day 90th. Total and differential leucocytic counts, total protein, albumin, IgA, IgG and IgM levels were measured in blood. There were insignificant (p>0.05) variations in the levels of total and differential leucocytic counts and total protein among the groups throughout the experiment. However, significant differences (p⟨0.05) were found in globulin, IgA, IgG and IgM in both (Y) and (YC) groups, but the effect of yeast culture seems to be better than that of the probiotic. In conclusions, the obtained results indicate that the tested probiotic and yeast culture improve the immunological status of lambs.

P0835IDENTIFYING THE FREQUENCY OF CHRONIC KIDNEY DISEASE OF UNKNOWN ETIOLOGY (CKDU) IN A RURAL POPULATION OF BANGLADESH

Background and Aims

The common etiologies of CKD are diabetes, hypertension and glomerulonephritis. Prevalence of CKD of unknown (CKDu) etiology is being increasingly considered as an emerging etiology, especially in the developing countries, with environmental predisposition to hot humid climate, dehydration and toxic metal contaminations. The aim was to identify the frequency of CKDu as an etiology in a rural population with environmental exposure.

Method

In this observational study subjects were selected from a geographically defined rural population in Bangladesh. Baseline information was recorded by the translated WHO STEP wise approach surveillance- Instrument v.3.1 (Core and Expanded). Blood Pressure was measured by digital blood pressure monitor. Serum creatinine was measured by enzymatic method using assays traceable to isotope dilution mass spectrometry (IDMS). A fasting blood sample and spot urine was collected. BP ≥140/90mmHg; FBS &gt; 5.6 mmol/l and HbA1c ≥6.5%; and eGFR&lt; 60ml/min (CKD-EPI equation) or urine ACR &gt; 30mg/g was taken as diagnostic cut-offs for hypertension, diabetes and nephropathy respectively. From diagnosed CKD patients CKDu group was further identified by stepwise approach of WHO criteria as suspected and probable stages.

Results

The mean age was 41.3 ± 12.7 years with male/female ratio 37/63 in preliminary 303 study subjects. They were 12.5% diabetic, 21% hypertensive and 75% had some form of dyslipidemia. Among all 51 subjects (16.8%) were diagnosed as CKD based on single measurement of eGFR and ACR. Of these 30 study subjects (58%) met the criteria of suspected CKDu. After repeat measures of eGFR and ACR at 3 months, prevalence of CKD came down to 10.2% persisting in 31 subjects (G1:5.3%, G2:2.3% and G3: 2.6%). Of these 7 study subjects (23%) met the criteria of probable CKDu. The main etiologies of CKD among these subjects were diabetic nephropathy (48%) followed by CKDu. The frequency of CKDu in total study population as a whole was 2.3%.The pattern of environmental exposures like types of farming, use of pesticide-fertilizer, NSAIDs intakes, water sources, amount of drinking water per day, duration of work under direct sun, pattern of fish-meat intakes, etc. were not different between subjects with CKDu versus the others.

Conclusion

The prevalence of chronic kidney disease in a rural area of Bangladesh is one in ten (10.2%). Among these nearly one-fourth (23%) of the subjects belonged to probable CKDu category. This alarmingly high frequency of CKDu needs further extensive evaluation to identify the predisposing factors responsible.

The 30-year cardiovascular risk profile of South Africans with diagnosed diabetes, undiagnosed diabetes, pre-diabetes or normoglycaemia: the Bellville, South Africa pilot study

Abstract

The aim of this pilot study was to assess the 30-year risk for cardiovascular disease (CVD) in the South Africa population of mixed-ancestry in individuals with non-diabetic hyperglycaemia, and undiagnosed and self-reported diabetes. Participants were drawn from an urban community of the Bellville South suburb of Cape Town. In total, 583 subjects without a history of CVD were eligible for lifetime CVD risk estimation. Gender-specific prediction for CVD risk was calculated using the 30-year CVD interactive risk calculator. High CVD risk (> 20%) was evident in normoglycaemic and younger subjects (under 35 years). The significant predictors of CVD were sibling history of diabetes, and triglyceride, low-density lipoprotein cholesterol and glycated haemoglobin levels (p < 0.001). The high lifetime risk in normoglycaemic and younger subjects may be considered a warning that CVD might take on epidemic proportions in the near future in this country. We recommend the inclusion of education on CVD in school and university curricula.

Optimal waist-to-height ratio values for cardiometabolic risk screening in an ethnically diverse sample of South African urban and rural school boys and girls

Background

The proposed waist-to-height ratio (WHtR) cut-off of 0.5 is less optimal for cardiometabolic risk screening in children in many settings. The purpose of this study was to determine the optimal WHtR for children from South Africa, and investigate variations by gender, ethnicity and residence in the achieved value.

Methods

Metabolic syndrome (MetS) components were measured in 1272 randomly selected learners, aged 10–16 years, comprising of 446 black Africans, 696 mixed-ancestry and 130 Caucasians. The Youden’s index and the closest-top-left (CTL) point approaches were used to derive WHtR cut-offs for diagnosing any two MetS components, excluding the waist circumference.

Results

The two approaches yielded similar cut-off in girls, 0.465 (sensitivity 50.0, specificity 69.5), but two different values in boys, 0.455 (42.9, 88.4) and 0.425 (60.3, 67.7) based on the Youden’s index and the CTL point, respectively. Furthermore, WHtR cut-off values derived differed substantially amongst the regions and ethnic groups investigated, whereby the highest cut-off was observed in semi-rural and white children, respectively, Youden’s index0.505 (31.6, 87.1) and CTL point 0.475 (44.4, 75.9).

Conclusion

The WHtR cut-off of 0.5 is less accurate for screening cardiovascular risk in South African children. The optimal value in this setting is likely gender and ethnicity-specific and sensitive to urbanization.

Chronic kidney diseases in mixed ancestry south African populations: prevalence, determinants and concordance between kidney function estimators

BACKGROUND

Population-based data on the burden of chronic kidney disease (CKD) in sub-Saharan Africa is still very limited. We assessed the prevalence and determinants of CKD, and evaluated the concordance of commonly advocated estimators of glomerular filtration rate (eGFR) in a mixed ancestry population from South Africa.

METHODS

Participants were a population-based sample of adults selected from the Bellville-South community in the metropolitan city of Cape Town. eGFR was based on the Cockroft-Gault (CG), Modification of Diet in Kidney Disease (MDRD) and CKD Epidemiology Collaboration (CKD-EPI) equations (with and without adjustment for ethnicity). Kidney function staging used the Kidney Disease Outcome Quality Initiative (KDOQI) classification. Logistic regressions and kappa statistic were used to investigate determinants of CKD and assess the agreement between different estimators.

RESULTS

The crude prevalence of CKD stage 3-5 was 14.8% for Cockcroft-Gault, 7.6% and 23.9% respectively for the MDRD with and without ethnicity correction, and 7.4% and 17.3% for the CKD-EPI equations with and without ethnicity correction. The highest agreement between GFR estimators was between MDRD and CKD-EPI equations, both with ethnicity correction, Kappa 0.91 (95% CI: 0.86-0.95), correlation coefficient 0.95 (95% CI: 0.94-0.96). In multivariable logistic regression models, sex, age and known hypertension were consistently associated with CKD stage 3-5 across the 5 estimators.

CONCLUSIONS

The prevalence of CKD stages greater than 3 is the highest reported in Africa. This study provides evidence for support of the CKD-EPI equation for eGFR reporting and CKD classification.

Three-year's changes in glucose tolerance status in the Bellville South cohort: rates and phenotypes associated with progression

AIMS

To determine the phenotypes associated with progression to type 2 diabetes or worsening in glucose tolerance during a 3-year follow-up of a community-based cohort in Cape Town, South Africa.

METHODS

A total of 198 eligible subjects (72.3% women) aged 55.2 years, from the Bellville-South community were followed-up between 2008 and 2011. Baseline and follow-up data collections included glucose tolerance status, anthropometric, blood pressure, lipids, insulin, γ-glutamyltransferase, cotinine, creatinine and HbA1c. Progression in glucose tolerance status at 3-year was the composite of new-onset diabetes and any worsening in glucose tolerance status.

RESULTS

The cumulative incidence of progression in glucose tolerance status was: 16.2% (32 participants including 11 with new-onset diabetes), and increased in a stepwise fashion with the number of components of metabolic syndrome (MetS). In age and sex-adjusted logistic regression analyses, MetS [odd ratio: 3.08 (95% CI: 1.34-7.10)], HbA1c [5.26 (1.94-14.24)], HDL-cholesterol [0.05 (0.01-0.33)], γ-glutamyltransferase [1.99 (1.07-3.67)], triglycerides [1.71 (1.13-2.58)] and total/HDL-cholesterol [1.45 (1.08-1.93)] were significant predictors of progression, while borderline effects were observed for baseline glucose and diastolic blood pressure. Markers of adiposity were mostly stable or improved among non-progressors during follow-up, but deteriorated significantly among progressors, resulting in significant statistical interactions.

CONCLUSIONS

High rates of deterioration of glucose status over time were found in our population, with nearly one-fifth of them acquiring a glucose tolerance worse status within a very short follow-up. Our study extends to this setting the well-known utility of phenotypes of MetS single or in combination, in predicting worsening in glucose tolerance status.

Assessment of Epstein-Barr virus in blood from patients with multiple sclerosis

Viruses such as Epstein-Barr virus (EBV) which can establish latent infections in the central nervous system or the immune system have been associated with chronic neurological disorders, including multiple sclerosis. Results vary, therefore the aim of this study was to investigate the presence of EBV using both viral DNA and antibody screening techniques, using PCR and ELISA assays respectively, to evaluate viral presence in blood from control subjects and patients with multiple sclerosis. Viral gene sequences for latent proteins EBNA-1 and LMP-1 and lytic gene BamH1-W were present equally in both patients and controls (<7%). Anti-EBV-VCA IgG positive cases were present in >99% of all study subjects, and anti-EBV-VCA IgG immune status ratio showed a near-significant positive correlation with the EDSS in patients with multiple sclerosis. In contrast, Anti-EBV-VCA IgM positive cases were significantly increased in patients (controls: 23.3%; patients; 41.9%; P = 0.046). The IgM to IgG immune status ratio was near-significantly higher in patients with relapse episodes in the year preceding blood sampling (P = 0.058). Results from this and previous studies have shown higher prevalence rates for EBV evaluating anti-EBV IgM positive cases against viral DNA positive cases. Also, IgM, an innate immune response, showed an association with relapse episodes, suggesting viral re-activation as a contributing factor to these relapses.

Distribution and association of hs-CRP with cardiovascular risk variables of metabolic syndrome in adolescent learners

OBJECTIVE

Metabolic syndrome (MetS) and its associated cardiovascular risk are on the increase in children. High-sensitivity C-reactive protein (hs-CRP) has emerged as a useful marker for inflammation associated with atherosclerosis and cardiovascular disease. Our aim was to determine the distribution of hs-CRP in an effort to identify the MetS variable that is critical in modulating plasma CRP levels in a population of South African adolescents.

DESIGN

A cross-sectional analytical study design was used for this investigation, where the dependent and independent variables were measured simultaneously.

METHODS

Anthropometric variables, blood pressure, fasting blood glucose and lipids were performed on 324 consenting learners aged 15-18 years from three different ethnic groups (Black, White and Coloured). The National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) for ages 15-18 year olds was used to define MetS.

RESULTS

The prevalence of MetS and obesity was 3.7% and 7.1%, respectively. The hs-CRP levels were significantly higher in subjects with a waist-circumference greater than the 90th percentile (p < 0.01) and in obese learners with MetS, but was lower in adolescents with normal weight and MetS. Median hs-CRP levels increased with an increasing number of metabolic abnormalities and exceeded 3 mg/L in 19% of adolescents. Gender and ethnic differences were observed.

CONCLUSION

Our findings suggest that obesity and waist circumference appear to be major mediators of hs-CRP levels in South African adolescents.

HbA1c of 6.5% to diagnose diabetes mellitus -- does it work for us? -- the Bellville South Africa study

Background

HbA1c has been the gold standard for glycaemic control follow-up for decades. In 2009, a level of 6.5% (48 mmol/mol) was proposed as diagnostic for diabetes. We test this cut-off in our community.

Methods

Participants (946) from a community-based study were screened for diabetes using either a fasting blood glucose or oral glucose tolerance test (OFTT). The HbA1c cut-off of 6.5% was tested for each group. A receiver operator characteristic (ROC) curve for both groups was generated to establish an optimal cut-off.

Results

Our study included 224 (23.7%) males and 722 (76.3%) females. Using fasting blood glucose alone, 117 (14%) were diagnosed with diabetes −50% had an HbA1c value of ≥6.5% (48 mmol/mol). Using an OGTT, 147 (18%) were diagnosed with diabetes −46% had an HbA1c value of ≥6.5% (48 mmol/mol). ROC curves found a level of 6.1% (43 mmol/mol) to be optimal in both groups (AUC 0.85 and 0.82 respectively). The sensitivities were 80% and 75% and the specificities 77% and 78% respectively.

Conclusions

A cut off of 6.5% (48 mmol/mol) is a good diagnostic tool with its high specificity; however the low sensitivity limits its use. We found a level of 6.1% (43 mmol/mol) to be optimal. This emphasizes the need for evidenced based values to be established in various population groups.

Peripheral blood mononuclear cell membrane fluidity and disease outcome in patients with multiple sclerosis

Immune cell membrane lipids are important determinants of membrane fluidity, eicosanoid production and phagocytosis and fatty acid metabolic abnormalities have been reported in immune cells from patients with multiple sclerosis. The aim of this study was to investigate the relationship between peripheral blood mononuclear cell membrane fluidity, permeability status, and disease outcome as measured by the Kurtzke expanded disability status scale. Phospholipids, fatty acids and cholesterol composition in peripheral blood mononuclear cells from 26 patients diagnosed with multiple sclerosis and 25 healthy control subjects were determined by colorimetric assay, gas chromatography and enzymatic assays, respectively. Membrane fluidity was calculated according to previously established formulae and correlated with C-reactive protein and the Kurtzke expanded disability status scale. There were no significant differences in membrane lipids in peripheral blood mononuclear cells from patients and controls. However, correlation studies showed lipid metabolic abnormalities, which were reflected in significant correlations between membrane fluidity as measured by both its fatty acid and phospholipid compositions, and the functional system scores. C-reactive protein showed positive correlations with phosphatidylcholine, phosphatidylserine, phosphatidylinositol and total phospholipids in membranes from control subjects. Metabolic abnormalities, as well as correlations between membrane fluidity and the functional system scores, suggested the involvement of these immune cell membranes in the disease progression. Furthermore, the changed relationship between membrane phospholipids and C-reactive protein, which has been shown to correlate with infectious episodes and clinical relapse, could be an indication of immune cell dysfunction in patients with multiple sclerosis.

Membrane saturated fatty acids and disease progression in multiple sclerosis patients

The risk of developing multiple sclerosis is associated with increased dietary intake of saturated fatty acids. We determined the fatty acid composition within the different phospholipid fractions of red blood and peripheral blood mononuclear cell membranes of 31 patients diagnosed with multiple sclerosis and 30 healthy control subjects using gas chromatography. Individual saturated fatty acids were correlated with the severity of neurological outcome as measured by the Kurtzke Expanded Disability Status Scale. Significant increases were found in multiple sclerosis peripheral blood mononuclear cell membrane sphingomyelin C14:0 and phosphatidylinositol C22:0. In the peripheral blood mononuclear cell membranes, C22:0 and C24:0 showed positive correlations, while C14:0, C16:0 and C20:0 showed inverse correlations with the Functional System Scores. In conclusion, this study is in accordance with previous studies that have shown an increase in shorter long-chain SATS in MS patients. In addition, this study also showed that higher C14:0 and C16:0 reflected better disease outcome as demonstrated by the inverse correlation with the EDSS and FSS. We have also characterized the specific SATS, that is, long-chain SATS that may increase the risk of developing MS.

Erythrocyte membrane fatty acids in patients with multiple sclerosis

Background

Reports on fatty acids levels in multiple sclerosis remain inconclusive.

Objective

To determine the erythrocyte membrane fatty acid levels in multiple sclerosis patients and correlate with Kurtzke Expanded Disability Status Scale.

Methods

Fatty acid composition of 31 multiple sclerosis and 30 control individuals were measured by gas chromatography.

Results

The membrane phosphatidylcholine C20:4 n – 6 concentration was lower in the multiple sclerosis patients when compared to that of the control group, P = 0.04 and it correlated inversely with the EDSS and FSS.

Conclusion

Decrease in C20:4 n – 6 in the erythrocyte membrane could be an indication of depleted plasma stores, and a reflection of disease severity.

Non-invasive diagnosis of H pylori infection: Evaluation of serological tests with and without current infection marker CIM

AIM: To evaluate the performance of commercially available immunochromatographic (ICT) and immunoblot tests covering the current infection marker CIM and conventional ELISA for the diagnosis of H pylori infection in adult dyspeptic patients.

METHODS: Consecutive non-treated dyspeptic patients undergoing diagnostic endoscopy were tested for H pylori infection by culture, rapid urease test, and histology of gastric biopsy specimens. Serum from 61 H pylori infected and 21 non-infected patients were tested for anti-H pylori IgG antibodies by commercial ELISA (AccuBind^TM ELISA, Monobind, USA), ICT (Assure^®H pylori Rapid Test, Genelabs Diagnostics, Singapore), and immunoblot (Helico Blot 2.1, Genelabs Diagnostics, Singapore) assays. ICT and immunoblot kits cover CIM among other parameters and their performance with and without CIM was evaluated separately.

RESULTS: Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of ELISA were 96.7%, 42.8%, 83.1%, 81.8%, and 82.9%, of ICT were 90.1%, 80.9%, 93.2%, 73.9%, and 87.8%, of ICT with CIM were 88.5%, 90.4%, 96.4%, 73.0%, and 89.0%, of immunoblot were 98.3%, 80.9%, 93.7%, 94.4%, and 93.9%, and of immunoblot with CIM were 98.3%, 90.4%, 96.7%, 95.0%, and 96.3%, respectively.

CONCLUSION: Immunoblot with CIM had the best performance. ICT with CIM was found to be more specific and accurate than the conventional ELISA and may be useful for non-invasive diagnosis of H pylori infection.

Prevalence of IgG antibody against measles, mumps and rubella in bangladeshi children: a pilot study to evaluate the need for integrated vaccination strategy

The present study was carried out to determine the seroprevalence of IgG antibodies in Bangladeshi children against measles (irrespective of vaccination status), mumps and rubella (MMR) to assess strategic need of combined vaccination for these diseases. A total of 456 children of 1 month to 15 years, were studied. Serum IgG antibodies against MMR were measured by enzyme-linked immunosorbent assay (ELISA). By 3 months, protective IgG antibody level (>40 AU for measles and mumps and >15 IU/ml for rubella) for the diseases found to be between 50% and 80% among the studied children. Protective measles antibody (IgG) was not detected in all the children of 3-9 months and significant number of children between 9 months and 5 years were unprotected (87-65%; P < 0.001). Moreover, children of 3-15 months had no protective antibody level against mumps and significant number of children between 15 months and 5 years were unprotected (92-71%; P < 0.001). Between 5 and 15 years of age, significant number of children became protective (63-85%, P < 0.001). Although, a majority of children between 3 months and 5 years had shown to have no protective antibody against rubella (89-71%; P < 0.01-0.001) between >10 and 15 years 71% children had protective level of antibodies (P < 0.001). No significant difference was observed in antibody prevalence regarding socioeconomic classes, nutritional status and parental education. The data showed that: (i) a significant number of children remain unprotected against MMR in childhood and (ii) an extensive nationwide survey is required to suggest an integrated vaccination strategy in order to implement appropriate control measures of the three infectious diseases.

Association of HLA class I antigen matching and early graft outcome in living donor kidney transplantation

INTRODUCTION

HLA antigen matching often plays an important role in organ transplantation. As for HLA class I antigen matching, there are differences of opinion regarding its influence on the outcome of renal transplantations. The aim of this study was to evaluate the association of HLA class I antigen matching with early graft outcomes in living donor kidney transplantation.

PATIENTS AND METHODS

We evaluated graft outcomes in the first month of transplantation. Major events were slow graft function (serum creatinine > 250 micromol/L at the end of first week), delayed graft function (patients requiring dialysis in first week), and acute rejection episode. Graft outcomes were compared for normal renal function (NRF, serum creatinine < or = 175 micromol/L) impaired renal function (IRF, serum creatinine > 175 micromol/L) or impaired graft function due to an acute rejection episode (IGF).

RESULTS

The 115 subjects had a mean age of 29 +/- 8 years and their donors 38 +/- 11 years (P < .01). Immunosuppression included prednisolone, azathioprine, and cyclosporine. Parents, siblings, and others were kidney donors in 46%, 33%, and 21%, respectively. Comparisons between NRF/IRF (serum creatinine 133 +/- 24 vs 201 +/- 36 micromol/L, P < .01) and NGF/IGF (serum creatinine 146 +/- 44 vs 161 +/- 39 micromol/L, P < .05) showed no difference in number or pattern of HLA matching.

CONCLUSION

HLA class I antigen matching may not produce an added influence on early graft outcome among living donor kidney transplantations.

Comparison between IS6110 and MPB64 primers for the diagnosis of Mycobacterium tuberculosis in Bangladesh by polymerase chain reaction (PCR)

The study was carried out to evaluate the efficacy of two different primers in PCR based diagnosis of tuberculosis on the basis of the time involvement, steps of PCR, cost and accuracy of results. Among 17 clinically suspected pulmonary tuberculosis patient's (M:F 65:35) sputum samples, 12 were found positive by both primers. Among 81 routine samples (sputum = 12; blood = 27; cerebrospinal fluid = 16; ascitic fluid = 12 and urine = 14), 12 were found to be positive by IS6110 primer while 13 were found positive by MPB64. The result of M. tuberculosis DNA PCR in sputum, ascitic fluid, CSF and urine samples were found to be similar in both the primers used. It is suggested that, M. tuberculosis DNA PCR in blood samples using MPB64 primers sometime gives false positive result and therefore, may not be recommended for blood samples. As in other samples both the primers gave almost the same result and therefore, both the primers can be used for MTB DNA PCR vice versa in order to cross check if one gives dubious result.

PCR can help early diagnosis of pulmonary tuberculosis

One hundred and fifty-one patients, clinically suspected for pulmonary tuberculosis (age: 31 +/- 13 years, male/female: 112/39), were investigated to evaluate the diagnostic potential of polymerase chain reaction (PCR) based detection of the Mycobacterium tuberculosis complex in sputum. The diagnostic efficacy of PCR was compared with culture of Mycobacterium tuberculosis on egg-based Lowenstein-Jensen modified medium. PCR detected 71.5% (108/151), whereas culture detected 66.2% (100/151) of the clinically suspected patients. There was a significant association between the results of PCR and culture (chi2 = 59.524, p < 0.001). However, 23.2% (35/151) samples were found negative in both culture and PCR. Considering culture as the gold standard, the sensitivity of the PCR was 92%. and its specificity 70%. This lower apparent specificity may be due to the higher sensitivity of PCR.

Chronic carriers of hepatitis B virus in Bangladesh: a comparative analysis of HBV-DNA, HBeAg/anti-HBe, and liver function tests

Serological markers of hepatitis B virus (HBV), liver function tests and quantitative estimation of HBV-DNA are important in the assessment of the state of infection and prognosis following treatment for hepatitis B. This study aimed to determine whether low-cost assays, eg hepatitis B e antigen (HBeAg) and liver function tests, could be used for the assessment of infectivity as an alternative to HBV-DNA estimation. We tested 125 hepatitis B carriers for HBeAg, antibody to HBeAg (anti-HBe), and serum HBV-DNA; we also carried out a range of standard liver function tests. Seventy-three subjects were positive and 52 were negative for HBeAg. Of the HBeAg positive cases, 3 were also positive for anti-HBe; of the HBeAg negative cases, 5 were also negative for anti-HBe. Of these 8 cases, 7 had no detectable HBV-DNA. Most of the HBeAg positive but anti-HBe negative subjects were positive for HBV-DNA (74.3%; 52/ 70) whereas most of the HBeAg negative and anti-HBe positive subjects (93.6%; 44/47) were also negative for HBV-DNA. Of 56 HBV-DNA positive individuals, alanine transaminase (ALT) was found to be raised in 69.6% (p=0.066) and aspartate transaminase (AST) was raised in 66.1% (p=0.011), while 67.9% had normal alkaline phosphatase (ALP) (p=0.054). HBeAg (p=0.018) and raised ALT (p=0.008) were found to be independent predictors for HBV-DNA positivity among HBV carriers. This study suggests that HBeAg positive and anti-HBe negative hepatitis B carriers with raised ALT and AST are likely to be positive for HBV-DNA; the combination of routine serology and biochemical tests may be considered as an alternative to HBV-DNA in evaluating the state of chronic HBV infection. However, HBV-DNA should be specifically assessed if discordance is observed between seromarkers and transaminases.

Predominance of the DEN-3 genotype during the recent dengue outbreak in Bangladesh

A recent outbreak of dengue in Bangladesh was marked by many fatal complications. As clinical virulence varies among the genotypes of dengue virus, a study was conducted to investigate the molecular genotypes of dengue in Bangladesh. Reverse transcription polymerase chain reaction was used to determine viral genotypes using oligonucleotide generic primers that produce a 511 bp product. The resulting product was typed by nested PCR with strain-specific primers, yielding 482 (DEN-1), 119 (DEN-2), 290 (DEN-3) and 392 (DEN-4), visualized on UV transilluminator after electrophoresis on 2% agarose gel stained with ethidium bromide. Of 45 clinically diagnosed dengue patients (mean age 28 years; male/female 30/15), 19 (42.2%) had detectable viral RNA in their blood. However, during the first 5 days of fever in 30 patients, the frequency was 60% (18/30), implying that the sooner serum is drawn after the fever, the greater the chances of detecting viral RNA. DEN-3 was detected in all except 2 patients who were infected with DEN-2. DEN-2 (two cases) and DEN-4 (one case) were present as co-infections with DEN-3. All of the patients presented with fever, anorexia and vomiting; many had headache and general body ache; a few had a rash. About a quarter had suffered episodes of bleeding, while ascites, pleural effusion and CNS symptoms were found in a few patients Patients positive for viral RNA were also positive for anti-dengue IgM (p=0.007) in subsequent sampling. The study suggests the predominance of DEN-3 infection with occasional co-infection with other types, during the recent outbreak of dengue in Bangladesh.

Prevalence of infectious diseases in Bangladeshi women living adjacent to a truck stand: HIV/STD/hepatitis/genital tract infections

BACKGROUND

Little is known about infection rates for human immunodeficiency virus (HIV) and other diseases that can be transmitted sexually in Bangladeshi women who may be at intermediate levels of risk--that is, women who are not commercial sex workers (CSWs) but whose sexual contacts may include men at high risk for STD. This study examines HIV/hepatitis/STD and other genital tract infections in women living near Tejgaon truck stand in Dhaka, Bangladesh.

METHODS

This population based study was conducted from January to December 1998. A random sample of 384 women provided urine and blood samples and participated in an interview; 261 of them also had a physical examination in which vaginal and cervical specimens were taken. Laboratory tests included PCR on urine and cervical swabs for gonorrhoea and chlamydia, culture for trichomoniasis, serology tests for syphilis, herpes simplex 2, hepatitis B, C, D, HIV1, HIV2, and clinical diagnoses of other genital tract infections.

RESULTS

None of the participants tested positive for HIV. In the 261 women who had a physical examination, trichomoniasis was detected in 19.5%, chlamydia in 3.4%, gonorrhoea in 5.4%, bacterial vaginosis in 37.2%, and candidiasis in 10%. In the full sample of 384 women, with tests of urine and blood, prevalence of infection with chlamydia, gonorrhoea, syphilis, and herpes simplex 2 was detected in 0%, 6.3%, 5.7%, and 32% respectively. Almost 50% of the subjects had ever been exposed to hepatitis B, 3.6% were currently infective, 1.6% had hepatitis C, and none had hepatitis D.

CONCLUSION

The high prevalence of certain of these infectious diseases indicates the need to implement prevention interventions with these women and, perhaps more importantly, with their male partners. Qualitative research is needed to provide insights into their sexual behaviour and the contexts in which high risk behaviours occur.

Genetic background of diabetic and nondiabetic sibs in young Bangladeshis

The prevalence of diabetes mellitus in the young is higher in Bangladesh like other Asian developing nations. Albeit, undernutrition has been shown to be associated with diabetes in the young, not all such individuals are diabetic. Diabetes Mellitus is a multigenic disease. In IDDM, DR3/4 heterozygotes were shown to have a greatly increased risk of developing the disease, suggesting the concept of genetic factor(s) being involved in the development of diabetes. Therefore, this study was undertaken to determine the distribution of HLA class II alleles (DRB) and to identify the HLA associated risk for developing diabetes mellitus in the young Bangladeshis. A total of fifty individuals were investigated. Half of them (n=25) were diabetic patients, registered in BIRDEM and half the participants were their non-diabetic sibs. A genomic DNA PCR and Enzyme Linked Probe Hybridization Assay (ELPHA, Bio-test, Germany) was used to determine HLA class II alleles (DRB1, DRB 3, 4, 5) by in vitro amplification of DRB gene. Among all the sero-equivalent antigens found in the study subjects, the prevalence of DR15 (DR2) was overrepresented, both in the diabetic subjects and in their non-diabetic sibs. Moreover, compared with the non-diabetic group the diabetic patients showed higher frequency of DR15 alleles (39 and 25%) though the difference was not significant (chisq. 1.7, p>0.05). Next to DR15, DR4 was the most prevalent HLA-DRB gene found in the study population. Interestingly, the frequency of DR4 was higher in the diabetic than in the non-diabetic group (20 vs. 14%). The study showed that the DR15 and DR4 were the most prevalent in the study population. Moreover, DR7 though not very significant, was higher in non-diabetic compared to their diabetic sibs. Comparison between the diabetic and non-diabetic sibs could have been interesting and significant but we could not confirm our findings, possibly, due to small sample size. A study in a larger paired sample of unrelated population is also needed to substantiate our findings, and also to prove the susceptibility or resistant haplotype in the young diabetic subjects.

Increased hepatocyte growth factor content in rat stomach during omeprazole treatment

BACKGROUND AND AIMS

Hepatocyte growth factor (HGF) is a potent mitogen of gastric epithelial cells, and its production is stimulated during the healing of gastric mucosal lesions. In this study, the effect of a proton pump inhibitor, omeprazole, on the production and degradation of HGF in the stomach was examined to elucidate the mechanism of the omeprazole-induced acceleration of gastric mucosal healing.

METHODS

Indomethacin-induced gastric mucosal lesions were induced in rats with or without omeprazole pretreatment. HGF gene expression and the content of HGF was investigated in the rat stomach. HGF degradation by gastric juice was also tested.

RESULTS

In omeprazole-treated rats, the healing of gastric mucosal lesions was accelerated in comparison with those of untreated rats. Although omeprazole treatment did not enhance the indomethacin-induced increase in HGF gene expression, it significantly augmented the gastric HGF content. Furthermore, omeprazole increased the gastric content not only of the inactive but also of the active heterodimeric form of HGF, and this appeared to be due to the inhibition of the HGF degradation by gastric juice.

CONCLUSION

Omeprazole-induced acceleration of gastric mucosal healing may be mediated at least in part by the reduced degradation of HGF in the stomach.

Prevalence of infectious diseases and drug abuse among Bangladeshi workers

Individuals seeking jobs abroad need health fitness certificates before entering into those countries. Medical screening of 43,213 Bangladeshi job seekers (M/F: 42,290/923) was carried out in our reference center during the period August, 1994 to May, 1996. Albeit male predominance, they represented middle and lower middle socio-economic class of the population from all over the country. All were young adults (age: 27.05+/-3.56 years; mean+/-SD) applying for job visas to different Asian countries. Physical examination and laboratory investigations including markers for several infectious diseases and drugs of abuse were carried out as required by countries recruiting the workers. Serological tests revealed that 1,884 (4.4%) of individuals were positive for hepatitis B surface antigen (HBsAg), 737 (1.7%) for Treponema pallidum hemagglutination (TPHA) and only 83 (0.2%) for antibody to human immunodeficiency virus (anti-HIV). However, we could not confirm any case of infection with HIV. Chest X-ray suggestive of pulmonary tuberculosis was found in 162 (0.4%) and on blood film, malarial parasites could be observed only in 4 cases. Their urine analysis revealed the presence of opiates or cannabinoids in 471 (1.1%) individuals. HBsAg-positive cases (p = 0.003) and abuse of opiates (p = 0.024) or cannabinoids (p = 0.002) were significantly higher among males. TPHA reactivity and chest X-ray suggestive of tuberculosis were found to be higher among opiates (p = 0.002 and 0.027) and cannabinoids (p = 0.000 for both) abused as well as with increasing age (p = 0.000). These results may represent a cross-sectional view of the prevalence of different infectious diseases and abuse of drugs among the young adult population of Bangladesh.

Nitric oxide products degrade chondroitin sulfates

Nitric oxide (NO) is a potent endogenous vasodilator that is elevated in response to inflammation. Inflammation also produces high levels of superoxide, which combines with NO to produce peroxynitrite (PN). We have previously reported that NO degrades heparin and heparan sulfate under acidic conditions and that PN degrades hyaluronan (HA) at neutral pH. Heparin and HA are glycosaminoglycans (GAGs) widely distributed in the extracellular matrix of tissues. Disruption of intestinal GAGs, particularly the chondroitin sulfates, were linked to inflammatory bowel diseases. Chondroitin sulfate A (CSA), chondroitin sulfate B (CSB), and chondroitin sulfate C (CSC) are constituents of the basement membranes of many tissues, including the intestine. The purpose of this study is to determine whether the NO donor S-nitroso-N-acetylpenicillamine (SNAP) and PN can degrade chondroitin sulfates in vitro. The NO donor SNAP (2 mM, pH 4.0) or PN (5 mM, pH 7.4) was incubated for at least 1 week at 37 degrees C with CSA, CSB, or CSC. Breakdown of CSA, CSB, and CSC was assessed by gel filtration chromatography and compared with untreated controls. Percentage degradation was calculated based on the change in peak height compared to the control. SNAP treatment partially degraded CSB and CSC, whereas PN partially degraded all three chondroitin sulfates. Nitric oxide mediated degradation of GAGs, and particularly chondroitin sulfates, may be an important pathway of inflammatory tissue damage.

Detection of hepatitis B surface antigen in pregnant women attending a public hospital for delivery: implication for vaccination strategy in Bangladesh

Routine antenatal hepatitis B surface antigen (HBsAg) screening and immunization of risk babies is very effective in preventing perinatal transmission of hepatitis B virus (HBV). We studied 1,800 parturients attending a public hospital to assess the rationale for such vaccination in Bangladesh. In one in every 29 deliveries (63 of 1,800 or 3.5%), the mother was found to be HBsAg positive. All were asymptomatic and many (41 of 63 or 65%) without risk factors would remain undetected if HBsAg screening were performed on selected groups. Most of the HBsAg-positive mothers (54 of 63 or 85.7%) were found to be chronic carriers and 30.2% (19 of 63) were also hepatitis B e antigen (HBeAg) positive, indicating high infectivity. Although 23 cord blood were positive for HBsAg or HBeAg, none were positive for IgM antibody to hepatitis B core antigen (IgM anti-HBc), suggesting transplacental transmission of the antigens rather than intrauterine infection. These findings are discussed in relation to the cost-effectiveness of routine prenatal screening and immunization of risk babies compared with universal infant immunization.

Effect of aging on gastrin receptor gene expression in rat stomach

Gastrin is a pivotal humoral factor which regulates gastric acid secretion through its receptors. There is no report, however, concerning the age-related changes of gastrin receptor gene expression in the stomach. Northern blot analysis and in situ hybridization were performed to clarify the changes of gastrin receptor expression during the aging. In situ hybridization clarified that gastrin receptor mRNA was expressed mainly in enterochromaffin-like (ECL) cells in adult rat gastric mucosa. With aging, gastrin receptor gene expression in the stomach increased with the concomitant increase in histidine decarboxylase mRNA. Since histidine decarboxylase is a marker of gastric ECL cells, the augmented gastrin receptor mRNA in aged rats may be caused by the increased ECL cells in gastric mucosa during the aging.

Prevalence of Helicobacter pylori in asymptomatic population--a pilot serological study in Bangladesh

Epidemiological reports reveal that H. pylori is distributed among all population in the world. The present cross-sectional study was undertaken to see the H. pylori seroprevalence rates among the asymptomatic adults, as yet reportedly no such data available in Bangladesh. Serum samples were collected from 181 consecutive subjects who attended at the health check-up centre of Bangladesh Institute of Diabeties, Endocrine and Metabolic Disorders (BIRDEM), Dhaka, during the period of August to November 1995 for medical check up. The mean age of these subjects was 30.33 years (range 20-44 yrs). Incidentally all were male and belonged to average socioeconomic class. H. pylori specific IgG antibody level was assayed by an enzyme immunoassay kit ElAgen (Clone system). Among the 181 subjects, 166 (92%) had H. pylori specific antibodies and 15 (8%) were seronegative. No significant difference (p < 0.90) in seroprevalence rates was observed among different age groups. However, the results of higher seroprevalence rates of H. pylori infection in these asymptomatic adult population of Bangladesh are consistent with that of Africa and India.

Developmental gene expression of gastrin receptor in rat stomach

Gastrin, which is present in fetal plasma, may have important roles in the development of gastric mucosa, since it is not only a potent stimulator of gastric acid secretion but also a growth promoting factor. Gastrin regulates various cellular functions via its receptors on cell membrane. Therefore, in order to elucidate a role for gastrin in the development of gastrointestinal system during gestation, Northern blot analysis was performed. The results of the study suggested that gastrin receptor is mainly present on parietal cells. Furthermore, proton pump and gastrin receptor gene expressions in parietal cells were strongly stimulated by the administration of exogenous gastrin. In conclusion, gastrin may be involved in the developmental change of parietal cells through its receptors.

Case report: torsion of a gravid horn of a didelphic uterus

Acute abdominal pain during pregnancy presents a dilemma as signs and symptoms are often modified. Abdominal massage by traditional birth attendants (TBAs') during early labour is a common practice in the rural population, as it is perceived to give a soothening effect to the labouring mother. Many instances of abruptio placentae were reported in the past by this procedure, and in this case, the clinical picture presented as an abruptio placenta. Malpresentation and failure to progress were the indications for caesarean section despite the fetal demise. Severe post partum haemorrhage and failure to contract despite massive oxytocics resulted in the hysterectomy of the gravid horn, leaving the other horn intact.

Erythropoietin stimulates proliferation of rat-cultured gastric mucosal cells

Most anemic patients with chronic renal failure have gastric mucosal lesions. However, these gastric lesions are often improved after the administration of recombinant human erythropoietin (rHuEPO). We have used the rat gastric mucosal cell line RGM-1, to examine the possibility that rHuEPO might directly stimulate the growth of gastric mucosal cells in vitro. Our results show that rHuEPO dose-dependently increased [3H]thymidine incorporation into RGM-1 cells and their expression of c-myc gene. In addition, 125I-rHuEPO specifically bound to RGM-1 cells, and moreover, erythropoietin receptor gene expression was detected by RT-PCR. We conclude that rHuEPO has a direct growth-promoting effect on RGM-1 cells, suggesting possible usefulness of rHuEPO administration for the treatment of gastric mucosal damage in patients with chronic renal failure.

Prepubertal periodontitis: a genetic analysis

Genetic factors were recognized as possible predisposing factors in the etiopathogenesis of prepubertal periodontitis (PP). Consequently, the present work was carried out to determine the possible mode of inheritance and if there were any associated chromosomal aberrations in cases with PP. The study included 3 families with probands manifesting PP (the families included 18 individuals). Pedigree analysis was carried out as well as chromosomal analysis. The results pointed out to the possibility of new mutations arising due to various environmental factors (including the use of pesticides and their handling), in addition to a possible autosomal recessive inheritance. Chromosomal analysis showed no association between a certain chromosomal aberration and PP. An interesting finding was that a girl proband proved to be Xo female, i.e. a case of Turner's syndrome. This could be considered the first report of Turner's syndrome with PP.

Regulation of C gamma 3 expression. Role of switch in the allotype-associated variation of human serum IgG3 levels

Serum IgG3 levels are associated with G3m allotypes in humans. However, the molecular basis of this association has not been understood. In this study we have analyzed the biologic half-life, the secretion, the cell surface expression, the cytoplasmic content, and the mRNA expression of different allotypes. The biologic properties of the allotypes did not differ. However, the frequency of cells with membrane IgG3, cytoplasmic IgG3, and C gamma 3 mRNA was decreased in donors with a low serum IgG3, whereas the level of C gamma 3 mRNA expression in individual cells did not differ among cells of the different allotypes. As these findings indicated a pretranscriptional control of C gamma 3 expression, genomic DNA from donors with different allotypes were also studied. Despite the absence of gross, allotype-related differences in the I gamma 3 regions, we favor an upstream cis-element influencing C gamma 3 switching as the most likely explanation for variations in IgG3 serum levels.

Regulation of C gamma 3 expression. Role of switch in the allotype-associated variation of human serum IgG3 levels

Serum IgG3 levels are associated with G3m allotypes in humans. However, the molecular basis of this association has not been understood. In this study we have analyzed the biologic half-life, the secretion, the cell surface expression, the cytoplasmic content, and the mRNA expression of different allotypes. The biologic properties of the allotypes did not differ. However, the frequency of cells with membrane IgG3, cytoplasmic IgG3, and C gamma 3 mRNA was decreased in donors with a low serum IgG3, whereas the level of C gamma 3 mRNA expression in individual cells did not differ among cells of the different allotypes. As these findings indicated a pretranscriptional control of C gamma 3 expression, genomic DNA from donors with different allotypes were also studied. Despite the absence of gross, allotype-related differences in the I gamma 3 regions, we favor an upstream cis-element influencing C gamma 3 switching as the most likely explanation for variations in IgG3 serum levels.

Biological half-life of normal and truncated human IgG3 in scid mice

The fractional catabolic rate of IgG in the body is regulated with precision in order to maintain appropriate serum concentrations. We have investigated the turnover rate of normal human IgG3, a newly identified, naturally occurring, truncated form of IgG3 and a human-mouse chimeric IgG3 antibody in an immunodeficient mouse strain, C.B-17 (SCID), lacking endogenous Ig. The half-life of non-truncated, normal serum IgG3 as well as the chimeric antibody was about 7 days, whereas truncated IgG3 had a shorter half-life of about 5 days. Due to the inherent immune defect, the SCID mouse could represent a versatile animal model for the determination of turnover rates, inasmuch as an immune response will not be mounted against foreign antigens.

Transcription, translation and secretion of both IgA subclasses in polyclonally activated human lymphocytes

To analyze human IgA subclass-specific mRNA we have developed RNA probes for quantitation of alpha 1 and alpha 2 heavy chain constant region genes by solution hybridization. Under our assay conditions, we can detect as little as 3 pg of specific mRNA and there is less than 2% cross-reactivity between the two IgA subclasses. Using this method, the relative proportions of IgA1 and IgA2 mRNA in pokeweed mitogen (PWM)-stimulated cells were found to be 66% and 34%, respectively, while in the Epstein-Barr virus (EBV)-stimulated cells they were 77% and 23%, respectively. Cytoplasmic staining of the plasma cells and determination of IgA subclass distribution by flow cytometry revealed an almost even distribution of the two IgA subclasses as induced by both activators. The culture supernatant contained 72% IgA1 and 28% IgA2 after PWM stimulation, while EBV stimulation induced 85% IgA1 and 15% IgA2. This report thus describes a method for the quantitative analysis of IgA subclass-specific mRNA. Furthermore, we present evidence that in response to in vitro stimulation of peripheral blood lymphocytes by polyclonal activators the IgA-producing B cells not only synthesize both isotypes but also have the potential to secrete them.