Role of non-coding RNAs in head and neck squamous cell carcinoma: A narrative review

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide with high recurrence, metastasis, and poor treatment outcome. Recent studies have reported that non-coding RNA (ncRNA) might play critical role in regulating different types of cancer. MicroRNAs (miRs) are short ncRNAs (20-25 nucleotides) responsible for post-transcriptional regulation of gene expression and may have a role in oncogenesis by acting as oncomiRs or tumor suppressor miRs. Long non-coding RNAs (lncRNAs) are heterogenous group of ncRNAs more than 200 nucleotides long, can act in cis and/or in trans, and have been also implicated in carcinogenesis. These molecules have been suggested to be promising candidates as diagnostic and prognostic biomarkers and for development of novel therapeutic approaches. In this review, we have summarized recent findings on role of these ncRNAs in HPV-negative (HPV-ve) and HPV-positive (HPV+ve) HNSCC. The available literature supports differential expression of both microRNAs and long non-coding RNAs, which include oncogenic ncRNAs (miR-21, miR-31, miR-155, miR-211, HOTAIR, and MALAT1) and tumor suppressor ncRNAs (let7d, miR-17, miR-375, miR-139, and MEG3) in HPV+ve HNSCC tumors as compared to HPV-ve tumors and they have distinct role in the pathophysiology of these two types of HNSCCs.

Lipid profile and fat patterning in children at a mean of 8.8 years after Kawasaki disease: a study from Northern India

OBJECTIVES

Kawasaki disease (KD) is an acute vasculitis that can result in coronary artery abnormalities (CAA). Higher risk of atherosclerosis has also been documented in those who do not develop CAA. We report herein the lipid profile and fat patterning in children with KD in a cohort from Northern India at a mean follow-up of 8.8 years after the acute stage. There is a paucity of literature on this aspect of KD.

METHODS

Twenty children, who had developed KD at least 5 years previously were enrolled along with age- and sex-matched controls. Cases and controls underwent anthropometric assessment using standardised techniques and instruments. Lipids were assayed only in the cases.

RESULTS

There was no significant difference in weight, height, mid-upper arm circumference, waist circumference, hip circumference and waist-to-hip ratio between cases and controls. Skinfold thickness (ST) at triceps, subscapular, midaxillary and suprailiac regions was similar in cases and controls. Biceps and medial calf ST was, however, significantly higher among girls with KD in 10-14.9 years age group. On comparison with cut-offs enumerated by the National Cholesterol Education Program (NCEP), 2 children with KD had borderline while 1 had undesirable levels of total cholesterol. Undesirable triglyceride levels were seen in 12 children. Ten children had HDL levels <35 mg/dl while 1 had borderline LDL levels.

CONCLUSIONS

Lipid abnormalities at a mean of 8.8 years after KD suggest that these patients may be prone to premature atherosclerosis. There were no significant differences in the anthropometric parameters and most of the ST.

Effect of exogenous copper on lipid peroxidation in rat hepatocytes. Possible involvement of protein kinase C

We have investigated the direct effect of copper on malondialdehyde formation in rat isolated hepatocytes. Copper was found to decrease the cell viability with concomitant production of ujalondialdehyde in a time related manner. In addition the protein kinase C activator, PMA, was found to have a synergistic effect with copper on rat hepatocytes. These results indicate that protein kinase C may be important in mediating hepatotoxicity after exposure to copper.

Hypermethylation of carcinogen metabolism genes, CYP1A1, CYP2A13 and GSTM1 genes in head and neck cancer

OBJECTIVES

To investigate the role of aberrant hypermethylation of carcinogen metabolism pathway genes, CYP1A1, CYP2A13 and GSTM1 in head and neck cancer independently as well as its relation to tobacco and alcohol consumption and CYP1A1 and CYP2A13 polymorphisms in Indian population.

METHODS

  Seventy-three histologically confirmed head and neck cancer patients undergoing treatment in Postgraduate Institute of Medical Education and Research, Chandigarh, India were recruited. Non-cancerous tissues were obtained from 19 trauma subjects undergoing maxillofacial surgery. Methylation-specific PCR was performed to determine the methylation status of selected genes.

RESULTS

The aberrant hypermethylation of CYP1A1, CYP2A13 and GSTM1 genes was found in cancer tissues with frequency of about 39.7%, 27.4%, and 58.1%, respectively, and in normal healthy tissues with a frequency of about 10.5%, 15.8%, and 20.0%, respectively. Hypermethylation of CYP1A1 (P 0.027) and GSTM1 (P 0.010) showed significant association with head and neck cancer. We also observed significant interaction between smoking and methylation status of CYP1A1 (P 0.029) and CYP2A13 (P -0.034) in head and neck cancer. No association was observed between methylation status and alcohol consumption, clinical features and genetic polymorphisms of CYP1A1 and CYP2A13.

CONCLUSIONS

  Hypermethylation of carcinogen metabolism pathway genes independently and in interaction with smoking is associated with increased risk of head and neck cancer.

Polymorphisms in CYP2A13 and UGT1A7 genes and head and neck cancer susceptibility in North Indians

OBJECTIVES

To examine role of genetic variants of CYP2A13 and UGT1A7 genes, involved in activation and detoxification of tobacco carcinogens, with risk of head and neck cancer as well as to assess the potential modifying role of gene-gene and gene-environment interactions.

METHODS

203 head and neck cancer patients and 201 healthy controls were genotyped for functional polymorphisms of CYP2A13 and UGT1A7 genes using polymerase chain reaction-restriction fragment length polymorphism, denaturing high-performance liquid chromatography and sequencing.

RESULTS

We identified two novel polymorphisms T478C and T494C in CYP2A13 gene which were associated with significantly reduced risk of cancer (OR 0.37; 95% CI 0.19-0.71; P < 0.05). A CYP2A13 haplotype carrying variant alleles of T478C/T494C was found to be associated with reduced risk of head and neck cancer (OR 0.42; 95% CI 0.22-0.78; P = 0. 005). Mutant 'T' allele of CYP2A13 C578T polymorphism was found to be present in cancer patients only. A sevenfold increased risk of cancer was observed in smokers with UGT1A7 low activity genotypes (OR 7.01; 95% CI 1.02-48.37; P < 0.05). UGT1A7 haplotype carrying C allele (T622C) showed 10-fold increased risk of cancer (OR 10.12; 95% CI 1.29-79.4; P < 0.05).

CONCLUSION

  Interplay between genetic variants of CYP2A13 and UGT1A7 genes and smoking may modulate susceptibility to head and neck cancer.

Serum and urine nitrite and citrulline levels among patients with systemic lupus erythematosus: a possible addition to activity parameters?

Nitric oxide (NO) plays a significant role in the inflammatory process and has been implicated in several autoimmune disorders. This study was carried out prospectively to estimate the levels of nitrite and citrulline in the serum and urine, as surrogate markers of NO production, among patients with systemic lupus erythematosus (SLE). Forty-seven patients and 44 age- and sex-matched, healthy volunteers were studied. Nitrite and citrulline were measured in serum and urine by spectrophotometry.Median serum nitrite and citrulline levels and urine citrulline levels were higher among patients as compared with controls (p < 0.05). Patients with skin involvement stood out and had higher median serum and urine citrulline levels (p < 0.05). Disease activity correlated with steroid dosage, serum nitrite levels, and serum and urine citrulline levels (p < 0.05). Steroid dosage correlated with serum citrulline level (p < 0.05). Serum and urine citrulline levels correlated with each other (p < 0.01). In the subset of 13 individuals with renal involvement, serum and urine citrulline levels correlated with each other (p < 0.01) as did urine nitrite and citrulline levels (p < 0.05).NO production is increased among patients with SLE, and this increase correlates with disease activity and dosage of steroids used. The addition of a urine test to measure NO production as a marker of disease activity using simple spectrophotometry can be a valuable adjunct to other tests, can obviate the need for drawing a blood sample for this purpose, and can be repeated as often as necessary.

Oxidative Status in Stable Renal Transplantation

Increased oxidative stress and hyperhomocysteinemia are frequently observed in patients with end-stage renal disease. The effects of kidney transplantation on oxidative state are incompletely understood. With an aim to evaluate the prevalence and severity of oxidative stress in living donor renal transplant recipients, we conducted a cross-sectional study. Thirty-five renal transplant recipients (mean age 34 years; body mass index 21.93 +/- 1.92) with normal renal function (mean serum creatinine 1.41 +/- 0.33 mg%) were enrolled in the study. All patients were on cyclosporine-based immunosuppression. We assessed serum nitric oxide (NO) levels, plasma total homocysteine levels (tHCy), and malonaldehyde (MDA) levels. We evaluated the antioxidant power ferric reducing ability of plasma (FRAP) assay. The mean duration to the first sampling was 9.23 months after transplantation. Fourteen age- and sex-matched normotensive people were used as controls. The mean tHCy was significantly higher among patients (15.29 +/- 0.66 mmol/L compared with controls (9.58 +/- 2.90 mmol/L; P < .05). The MDA levels in patients (6.405 +/- 2.05 nmol/mL) were comparable to controls (6.093 +/- 1.93 nmol/mL; P = .099). The status of antioxidative power as measured by FRAP showed a trend to higher antioxidative status (697.57 +/- 103.07 mmol/L) in patients compared with controls (518 +/- 120.99 mmol/L; P = NS). The mean NO levels in patients (545.01 +/- 281.49 mmol/mL) were significantly higher than controls (183.49 +/- 64.53 nmol/mL; P < .05). Stable renal transplant recipients display a pattern of increased oxidant stress that may be counterbalanced by an enhanced antioxidant mechanisms.

Hyperhomocysteinemia as a risk factor for ischemic stroke: an Indian scenario

BACKGROUND

Hyperhomocysteinemia has been proposed as an important risk factor for ischemic stroke worldwide, but data available from the Indian subcontinent is scarce.

AIM

To study homocysteine levels in patients with ischemic stroke and compare it with age- and sex-matched controls.

SETTINGS AND DESIGN

Case-control prospective study.

MATERIALS AND METHODS

Fifty-seven patients with ischemic stroke and 30 controls were recruited for the study. They were subdivided into two subgroups (< 40 years and> 40 years of age) and plasma fasting total homocysteine (tHcy) levels were measured.

STATISTICAL ANALYSIS USED

Student's 't' test and chi-square test.

RESULTS

The tHcy were significantly high in patients with stroke, compared to controls (9.91 +/- 2.25 vs 8.00 +/- 2.74 micromol/l; P vs 8.45 +/- 2.72 micromol/l; P = 0.01) and female patients compared to controls (9.08 +/- 1.81 vs 6.79 +/- 2.60 micromol/l; P = 0.04). The tHcy levels were significantly high in patients with hypertension compared to normotensive patients (10.96 vs 9.49 micromol/l; P = 0.01) and smokers compared to nonsmokers (11.17 vs 9.33 micromol/l; P = 0.01).

CONCLUSIONS

Hyperhomo-cysteinemia emerged as an important independent risk factor for ischemic stroke. A strong positive correlation was also observed between hypertension, smoking, and high-tHcy levels in the present study.

Biochemical and molecular markers in renal cell carcinoma: an update and future prospects

Cancer is a big problem in the developed world as well as in developing countries. Renal cell carcinoma (RCC) accounts for approximately 3% of adult malignancies and 90-95% of neoplasms arising from the kidney. RCC is more common in men than in women (2:1), and it most often occurs in patients between the ages of 50-70 years. In all cancers the cancerous cells release particular kind of proteins (called tumour markers) and blood tests are used to detect the presence of these markers. These tumour markers nowadays are an area of interest for oncologists who search for a possible solution in the detection and treatment of RCC. Different kinds of biochemical and molecular markers such as ferritin, MN/CA9, apoptotic index, p53, IL-2, gamma-enolase, CD44, CD95, chromosome instability and loss of heterozygosity have been tested in RCC, but so far no marker fulfils one or the other criteria to be considered as an ideal marker for RCC. This review gives basic and updated information about the different kinds of biomarkers studied in RCC and about the role implementation of genomics and proteomics in RCC.

Antitubercular therapy decreases nitric oxide production in HIV/TB coinfected patients

BACKGROUND

Nitric oxide (NO) production is increased among patients with human immunodeficiency virus (HIV) infection and also those with tuberculosis (TB). In this study we sought to determine if there was increased NO production among patients with HIV/TB coinfection and the effect of four weeks chemotherapy on this level.

PATIENTS AND METHODS

19 patients with HIV/TB coinfection were studied. They were treated with standard four drug antitubercular therapy and sampled at baseline and four weeks. 20 patients with HIV infection but no opportunistic infections were disease controls and 20 individuals as healthy controls. Nitrite and citrulline, surrogate markers for NO, were measured it spectrophotometrically.

RESULTS

Mean age of HIV/TB patients was 28.4+6.8 years and CD4 count was 116+36.6/mm3. Mean nitrite level among HIV/TB coinfected was 207.6+48.8 nmol/ml. This was significantly higher than 99.7+26.5 nmol/ml, the value for HIV infected without opportunistic infections and 46.4+16.2 nmol/ml, the value for healthy controls (p value <0.01). Level of HIV/TB coinfected declined to 144.5+ 34.4 nmol/ml at four weeks of therapy (p value < 0.05). Mean citrulline among HIV/TB coinfected was 1446.8+468.8 nmol/ml. This was significantly higher than 880.8+ 434.8 nmol/ml, the value for HIV infected without opportunistic infections and 486.6+212.5 nmol/ml, the value for healthy controls (p value <0.01). Levels of HIV/TB infected declined to 1116.2+388.6 nmol/ml at four weeks of therapy (p value <0.05).

CONCLUSION

NO production is elevated among patients with HIV infection, especially so among HIV/TB coinfected, but declines significantly following 4 weeks of antitubercular therapy.

Enalapril acts through release of nitric oxide in patients with essential hypertension

BACKGROUND

Endothelial dysfunction has been proposed as an etiological agent in the pathogenesis of essential hypertension. Amongst the various antihypertensive drugs, angiotensin converting enzyme inhibitors (ACEI) have been implicated in modifying the vascular endothelium by the release of mediators that include bradykinin, nitric oxide, prostaglandins and thromboxane A2.

MATERIALS AND METHODS

To study the mechanism of action of enalapril, an ACEI, serum reactive nitrite intermediates (RNI) and citrulline, by products of nitric oxide metabolism were measured before and after treatment with enalapril in 25 consecutive patients of essential hypertension.

RESULTS

Following treatment serum RNI intermediate increased from a pretreatment value of 164.5 +/- 20.2 nmol/mL to a post treatment value of 266.9 +/- 47.3 nmol/mL (p < 0.05), however there was no significant change in the levels of citrulline (p > 0.1). There was no significant correlation between the severity of hypertension and serum RNI. Serum RNI levels were lower in the postmenopausal women but did not reach statistical significance.

CONCLUSIONS

It is postulated that enalapril exhibits its antihypertensive property through release of nitric oxide.

Calcium supplementation in pre-eclampsia

OBJECTIVE

The objective of this prospective, open, randomised trial was to determine the role of calcium supplementation in preventing pre-eclampsia.

METHODS

One hundred uncomplicated normotensive primigravidae were enrolled in the study before 20 weeks of pregnancy. Fifty each were randomised to receive either two gram elemental calcium daily from 20 weeks of gestation to delivery (study group) or no calcium supplementation (control group). Prior to 20 weeks of gestation each underwent a complete clinical and laboratory evaluation. Serum and urine calcium was measured first at 20 weeks of gestation and then at 24-28 weeks and at 32-36 weeks of pregnancy.

RESULTS

Patient characteristics at the start of therapy were similar in the two groups. Blood pressure profile was similar throughout pregnancy in the groups. The incidence of pre-eclampsia was similar (18% in the study group and 16% in the control group), but severe pre-eclampsia was significantly less in the study group. There was no significant difference between the two groups with regards to intra- and postpartum characteristics, perinatal outcome and maternal or fetal side effects. Serum and urinary calcium levels did not differ between the two groups.

CONCLUSION

While calcium supplementation did not lower the incidence of pre-eclampsia it did reduce its severity.

Elevated nitric oxide production in patients with primary Sjögren's syndrome

Nitric oxide (NO) production is elevated in patients with inflammatory disorders. We have previously shown increased NO production in patients with rheumatoid arthritis and systemic lupus erythematosus. In this study we used nitrite and citrulline levels as surrogate markers of NO production in patients with primary Sjögren's syndrome (SS) and measured their levels by spectrophotometry. Fifteen patients and 15 age- and sex-matched controls were studied. Mean nitrite levels in patients were 582.3+/-208.3 nmol/ml, but those in controls were significantly lower, at 203.2-106.9 nmol/ml (p<0.001). Citrulline levels were 2820.4+/-933.9 nmol/ml in patients and were significantly higher than 217.4+/-144.8 nmol/ml, the levels in controls (p<0.0001). Mean levels of both nitrite and citrulline were significantly higher in patients with arthritis than in those who had no joint manifestations (p<0.05). There was no correlation between NO production and other variables, such as age, disease duration, drug therapy and antinuclear antibodies or rheumatoid factor positivity. Increased NO production may be partly a reflection of the presence of arthritis in five patients. It is concluded that there is increased NO production in patients with primary SS, especially if they have associated arthritis.

Increased nitric oxide production in patients with systemic sclerosis

Nitric oxide (NO, nitrogen monoxide) is a messenger molecule whose synthesis can be induced by proinflammatory cytokines. Increased production of NO has been reported in various inflammatory and autoimmune diseases. We studied serum nitrite and citrulline as surrogate markers for NO production in patients with systemic sclerosis (SSc) and looked for correlation with extent of disease, disease duration, age, and systemic involvement. Thirty-four patients were studied against 20 controls. The nitrite levels were significantly higher in the disease group (1588.4 +/- 998.2 nmol/ml compared to 327.8 +/- 137.7 nmol/ml; P < 0.001). The citrulline levels of the disease group were also significantly higher (5490.1 +/- 2518.3 nmol/ml compared to 3264.5 +/- 2509.7 nmol/ml in the controls; P = 0.005). There was no significant difference among limited and diffuse subgroups. There was no significant difference in patients with or without arthritis or interstitial lung disease or with other systemic involvement. On multivariate analysis there was a trend toward a rising level of nitrite with worsening lung functions (P = 0.07). Hence, there is evidence of increased NO production in patients with SSc. There is no difference between NO levels in disease subgroups or those with systemic involvement.

Role of anaerobiosis in virulence of Salmonella typhimurium

Intestinal pathogens are exposed to various stress conditions during their infectious cycle. Anaerobiosis, one of such hostile condition, is offered by the host within gut and intestinal lumen, where survival, multiplication and entry into intestinal epithelial cells is priority for the invading pathogen. In the present study, a virulent strain of S. typhimurium (1402/84) was grown under anaerobic conditions and its virulence characteristics such as host cell binding, penetration and intracellular survival were compared with aerobic S. typhimurium. Anaerobically grown S. typhimurium showed significantly higher binding to immobilized mice enterocytes and intestinal mucus as compared to bacteria grown aerobically. Anaerobic bacteria also showed an early penetration of mucus and subsequent binding to underlying immobilized enterocytes, in vitro. Anaerobic S. typhimurium exhibited increased intracellular survival within spleen macrophages of mice and caused significantly higher fluid accumulation in ligated rabbit ileal loops as compared to aerobic bacteria. LD50 of anaerobic S. typhimurium was also observed to be 2 fold lower when compared to aerobic bacteria. Cell surface hydrophobicity of anaerobic S. typhimurium was also found to be significantly higher than aerobic bacteria. Thus, it appears that exposure of S. typhimurium to anaerobiosis results in its enhanced virulence, adhesion and penetration of host cells.

Pentoxiphylline reduces nitric oxide production among patients with HIV infection

Tumour necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) levels are elevated among patients with human immunodeficiency virus (HIV) infection. TNF-alpha is known to lower NO production. In this study we used a TNF-alpha inhibitor, pentoxiphylline, to treat patients with HIV infection who were free of opportunistic infections and see if NO production was altered with this drug. NO production was determined by spectrophotometric analysis using nitrite and citrulline as surrogate markers and TNF-alpha levels were determined by ELISA before and after 4 weeks of the treatment. Nineteen patients (ten males, mean age 36.6+/-5.2 years) and 16 age and sex matched healthy controls were studied. Mean CD4 counts of patients were 206.5 mm(3). Nitrite level among patients at recruitment was 99.7+/-26.5 nmol/ml (range 50-167 nmol/ml) and was significantly higher than 46.4+/-16.2 nmol/ml; the value of healthy controls (P<0.05). Patient levels declined significantly to 44. 2+/-19.7 nmol/ml (range 10-106.6 nmol/ml) following 4 weeks of therapy (P<0.01). Citrulline level at recruitment was 810.8+/-425.8 nmol/ml (range 366.6-1888.7 nmol/ml), which was significantly higher than 488.6+/-224.5 nmol/ml, the level of controls (P<0.01). There was a statistically significant decrease in these levels among patients to 533.6+/-299.5 nmol/ml (range 250-163.4 nmol/ml) after 4 weeks of therapy (P<0.01). TNF-alpha levels showed a significant decline in the OD values from 0.34+/-0.22 at the start of therapy to 0.24+/-0.18 (P<0.05). We conclude that the use of pentoxiphylline is associated with decrease in TNF-alpha levels and NO production.

Effect of oral magnesium supplementation on blood pressure, platelet aggregation and calcium handling in deoxycorticosterone acetate induced hypertension in rats

OBJECTIVE

To study the effect of oral magnesium supplementation on blood pressure, platelet aggregation and platelet calcium handling in deoxycorticosterone acetate (DOCA)-induced hypertension in rats.

DESIGN AND METHODS

Rats were divided into four groups of 20 each. Drug treatments were given for a 6-week period. Control rats were vehicle treated. In the second group, DOCA, 15 mg/kg, was injected subcutaneously twice weekly with 1% NaCl used instead of drinking water. The third group was given magnesium oxide (MgO), 1 g/kg daily, orally by gavage. The fourth group was given MgO along with DOCA and 1% NaCl. Blood pressure and heart rate were measured weekly. Platelet aggregation, intracellular calcium, calcium uptake and calcium efflux studies were performed at the end of sixth week. Serum magnesium concentration, plasma levels of reactive nitrogen intermediates (RNI) and citrulline were also measured

RESULTS

There was a significant rise in blood pressure in the DOCA-treated rats. Magnesium prevented the gradual rise in blood pressure when given along with DOCA, but had no effect in normotensive rats. Heart rate did not show any significant change. Platelet aggregation was significantly reduced in all the treatment groups compared to the control group. DOCA treatment produced a significant increase in the intracellular calcium concentration as well as the calcium uptake compared to the control group. Magnesium supplementation inhibited the increased intracellular calcium concentration and calcium uptake in DOCA-treated rats. RNI and citrulline levels were elevated in all the treatment groups. Serum magnesium levels were significantly higher in the magnesium-treated and DOCA plus magnesium-treated rats.

CONCLUSIONS

Magnesium supplementation prevents blood pressure elevation in DOCA hypertensive rats. These effects are associated with inhibition of platelet calcium uptake and decreased intracellular free calcium concentration.

Intestinal mucins: the binding sites for Salmonella typhimurium

Mucus-bacterial interactions in the gastrointestinal tract and their impact on subsequent enteric infections are poorly delineated. In the present study, we have examined the binding of Salmonella typhimurium to rat intestinal mucus and characterized a mucus protein (Mucus-Rs) which specifically binds to S. typhimurium. Both virulent (1402/84), and avirulent (SF 1835) S. typhimurium were observed to bind to crude mucus, however, the virulent strain showed 6 fold more binding as compared to avirulent strain. Fractionation of crude mucus on sepharose CL-6B resolved it into three major peaks. Maximal bacterial binding was observed with a high mol. wt. glycoprotein corresponding to neutral mucin. SDS-PAGE of purified protein (termed Mucus-Rs) under non reducing conditions showed it to be a homogenous glycoprotein (mol. wt. 250 kDa), while under reducing conditions, three bands corresponding to mol. wt. of 118,75 and 60 kDa were observed. Pretreatment of Mucus-Rs with pronase, trypsin and sodium metaperiodate markedly inhibited bacterial binding. GLC analysis of Mucus-Rs showed it to contain Mannose, Glucose, Galactose, Glucosamine, Galactosamine and Sialic acid as main sugars. Competitive binding in the presence of various sugars and lectins indicated the involvement of mannose in the mucus-bacterial interactions. The Mucus-Rs binding was highly specific for S. typhimurium; no significant binding was seen with E. coli and V. cholerae. Thus, we conclude that S. typhimurium specifically binds to a 250 kDa neutral mucin of intestinal tract. This binding appears to occur via specific adhesin-receptor interactions involving bacterial pili and mannose of neutral mucin.

Nitric oxide production is increased in patients with inflammatory myositis

Nitric oxide (NO) production is increased in several inflammatory disorders. We have previously demonstrated higher levels of NO production among patients with rheumatoid arthritis and systemic lupus erythematosus. In this study we measured serum levels of nitrite and citrulline using calorimetric methods as surrogate markers of NO production among patients with inflammatory myositis (IM). Twenty patients with IM and 19 age- and sex-matched controls were studied. Serum nitrite levels were significantly higher among patients than among controls (986.6 +/- 880 and 204.3 +/- 113.9 nmol/ml, respectively; P = 0.001). Serum citrulline levels, too, were significantly higher among patients than among controls (3755.7 +/- 1905.5 and 189 +/- 177.2 nmol/ml, respectively; P < 0.0001). There was a positive correlation between steroid dosage and serum citrulline levels (r = 0.51, P = 0.036) and a negative correlation between steroid dosage and disease duration (r = -0.54, P = 0.025). It was concluded that NO production is increased in patients with IM and those with more active disease, as indicated by higher steroid dosage, have higher serum citrulline levels.

Nitric oxide synthesis is increased in patients with systemic lupus erythematosus

Nitric oxide (NO) is believed to have a role in the inflammatory process. NO production was measured in 26 patients with systemic lupus erythematosus (SLE) and 20 healthy volunteers, using spectrophotometrically determined serum nitrite and citrulline as surrogate markers. Both nitrite and citrulline levels were significantly higher in patients with SLE than in controls (P < 0.001). Twelve and 10 patients, respectively, with SLE had nitrite and citrulline levels that were two standard deviations higher than the mean level of controls. These patients had a significantly higher measure of disease activity (SLE Disease Activity Index). These data show that there is increased NO production in SLE and that it may serve as a marker for disease activity.

Can fingernail creatinine concentrations be used to predict duration of azotemia?

Clinical use of fingernail creatinine estimation to predict duration of azotemia is yet to be validated. We studied the fingernail creatinine concentrations in 48 subjects: seven controls, nine with acute renal failure, five with rapidly progressive glomerulonephritis, 12 with chronic renal failure and 15 with end-stage renal failure on maintenance hemodialysis. The creatinine concentration in aqueous eluates of powdered nail clippings was determined by the alkaline picrate reaction. The mean fingernail creatinine concentration was significantly higher in patients with chronic renal failure (93.7 +/- 83.7 micrograms/g) and end-stage renal disease on maintenance hemodialysis (118.4 +/- 46.8 micrograms/g) as compared to those with acute renal failure (36.6 +/- 23.7 micrograms/g) and rapidly progressive glomerulonephritis (35.8 +/- 20.6 micrograms/g). The creatinine concentrations did not differ significantly between normal subjects (27.2 +/- 28.7 micrograms/g) and those with acute renal failure and rapidly progressive glomerulonephritis. However because of large variability in the values of fingernail creatinine concentrations within each group, the test lacked specificity. Therefore, this investigation is an unreliable indicator of duration of azotemia in individual patients and is not likely to be of much clinical use.

Platelet calcium pump activity in essential hypertensives and their first-degree relatives

Intracellular free Ca2+ concentration has been shown to be elevated in platelets of patients with essential hypertension. This study was designed to characterize Ca(2+)-pump activity of the platelet membranes (surface and intracellular) in these patients A double-blind study was carried out. Untreated and treated (on beta-blockers) essential hypertensives were studied in comparison with normotensive control subjects. First degree blood relatives of essential hypertensives were also studied. The Ca2+ activation kinetics of the enzyme showed a significant decrease in the Vmax (for the plasma- and intracellular membranes) and Km (for the intracellular membranes) in the essential hypertensive patients. Increased platelet membrane cholesterol content was observed in these patients. Lowered Ca2(+)-efflux by Ca2(+)-ATPase may lead to elevated intracellular free Ca2(+)-levels in platelet of essential hypertensives. A lowered Ca2(+) -ATPase activity may emerge as a marker for essential hypertension.

Role of reactive oxygen species in renal damage in experimental leprosy

Renal involvement is known to occur in leprosy. In the present study the possible role of reactive oxygen species (ROS) in causation of renal damage in mice infected with Mycobacterium leprae has been investigated. At least six animals from each group (control and infected) were killed at 0 day, 3, 6 and 9 months postinfection. The results showed a significant increase in the chemiluminescence (CL) response of peritoneal macrophages which was maximum between 3 and 6 months. No significant increase was observed in CL response of blood neutrophils. A significant increase in lipid peroxidation was observed at 3 and 6 months as evident by an increase in malondialdehyde levels. The increased ROS production might be the cause of lipid peroxidation. The renal damage is alos evident by decrease in the activity of renal brush border membrane enzymes, namely, alkaline phosphatase, leucine aminopeptidase and r-glutamyl transpeptidase. Thus ROS might play a role during early stages of M. leprae infection but in the later stages other immunological mechanisms may overpower the effect of ROS.

Staphylococcal enterotoxin-B (SEB) alters [14C]-choline transport and phosphatidylcholine metabolism in cultured human kidney proximal tubular cells

We studied the effects of SEB on [14C]-choline transport and metabolism of choline containing phospholipids in cultured human kidney proximal tubular (PT) cells. SEB increased the uptake of [14C]-choline in PT cells as a function of toxin concentration, incubation time, and pH. The maximum increase in uptake (3.5-5-fold compared to control) was observed at a toxin concentration of 10 micrograms/10(4) cells, at 4 h and at pH 7.4. Two toxins structurally related to SEB, Staphylococcal enterotoxin-A and toxic shock toxin (TST-1) failed to alter [14C]-choline uptake in PT cells, a finding which indicates that SEB-mediated alteration in choline uptake in PT cells has high specificity. We found that SEB markedly and significantly increased the incorporation of [14C]-choline into phosphatidylcholine, Iysophosphatidylcholine and sphingomyelin, but not into phosphatidylethanolamine. Maximum increase in the incorporation of [14C]-choline into phosphatidylcholine (3-fold compared to control) was observed at 4 h after incubation with toxin. In contrast, SEB did not alter the incorporation of [14C]-choline in phosphatidylethanolamine. The cellular level of phosphatidylcholine was also increased (2-fold compared to control) in PT cells incubated with SEB. This was accompanied by a 3-to-4-fold increase in CTP; phosphocholine, cytidyltransferase activity. In sum, SEB specifically stimulates phosphatidylcholine synthesis in PT cells by increasing choline uptake or by activating CTP: phosphocholine, cytidyltransferase, or both. We believe this is the first-ever report indicating that a toxin can increase phosphatidylcholine synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Digalactosylceramide is the receptor for staphylococcal enterotoxin-B in human kidney proximal tubular cells

We have characterized a glycosphingolipid (GSL) receptor for Staphylococcus enterotoxin-B (SEB) in cultured human kidney proximal tubular (PT) cells. Solid-phase binding of [125I]SEB to the GSL receptor was concentration dependent and was not displaceable by two structurally related toxins, such as staphylococcal enterotoxin-A and toxic shock syndrome toxin-1. Rat kidney cells did not bind [125I]SEB. However, when the rat kidney cells were pre-incubated with digalactosylceramide, there was a concentration-dependent binding of [125I]SEB. Trimethylsilyl derivatization of methyl glycosides, followed by gas-liquid chromatography-mass spectrometry (GC-MS), revealed that galactose was the major sugar component of this putative receptor GSL. The sphingosines present in this GSL were d18:2, d22:2 and d23:0; the fatty acids present were palmitate, oleate and stearate. Permethylation of alditol acetates and GC-MS revealed two predominant sugars, namely 2, 3, 4 and 6 tetramethylgalactital and 2, 3 and 6 trimethylgalactital. The GSL receptor for SEB was sensitive to alpha-galactosidase, and resistant to beta-galactosidase and beta-glucosidase. Taken together, our studies reveal that the tentative structure of the receptor for SEB in human kidney PT cells is CerGal alpha 1-->4Gal. In summary, we have identified a GSL as one of the binding sites of SEB, a food-borne toxin. We believe that our finding may open up rational approaches for the therapy of SEB-induced glycopathology in man.

Duodenal ulcer. Calcium status in isolated parietal cells

Although the etiology of duodenal ulcer is not known, its treatment with drugs that reduce acid secretion is well accepted. The central role of calcium in stimulus-secretion coupling resulting in acid secretion by gastric parietal cells is documented. However, the status of intracellular calcium in gastric parietal cells in the basal state in patients with duodenal ulcer is not known. Multiple endoscopic gastric mucosal biopsies from the corpus of the stomach of 52 patients were processed and isolated parietal cells were studied. Intracellular calcium was estimated using fura-2-acetoxymethyl ester. Influx and efflux were determined by using radioactive calcium. Acridine orange retention was used to assess acid production. Only calcium influx at 20 min was significantly (P < 0.01) more in patients with duodenal ulcer as compared to the control group. There was no difference between the groups in calcium influx at 0 and 60 min; calcium efflux at 0, 20, and 60 min; intracellular free calcium and acid secretion. We conclude that in the unstimulated state calcium homeostasis in isolated parietal cells of patients with duodenal ulcer shows only a minimal difference as compared to controls.

Ca2+ transport in unstimulated platelets of essential hypertensives and their blood relatives

OBJECTIVE

Intracellular free Ca2+ concentration has been shown to be elevated in platelets from essential hypertensive patients. This study was designed to characterize Ca2+ homeostasis in platelets of essential hypertensives.

DESIGN

A double-blind study was carried out. Untreated and treated (propranolol therapy) essential hypertensives were studied in comparison with normotensive control subjects. First-degree blood relatives of essential hypertensives were also studied. The various procedures used in the study were already standardized and well-established methods.

METHOD

For Ca2+ uptake and efflux studies, 45Ca was used. For intracellular free Ca2+ concentration studies the fluorescent Ca2+ chelator dye fura-2/acetoxymethyl ester (fura-2/AM) was used.

RESULTS

The uptake of 45Ca by unstimulated platelets of untreated essential hypertensives and their relatives was significantly higher than for controls. However, essential hypertensives treated with a beta-blocker drug showed no significant difference in Ca2+ uptake compared with controls. A significantly decreased Ca2+ efflux was observed in essential hypertensives (both untreated and treated) compared with controls. Relatives also showed a depressed Ca2+ efflux compared with controls.

CONCLUSIONS

It appears that the elevated intracellular free Ca2+ concentration levels in platelets (also observed by us) may be due to both an enhanced uptake into, and decreased efflux of Ca2+ from, the cell. Beta-blocker therapy may help to normalize the elevated intracellular free Ca2+ concentration levels observed in essential hypertensives. Relatives exhibit a state predisposed towards the development of hypertension.

Salmonella typhimurium enterotoxin mediated fluid secretion

Unidirectional Na+ and Cl- fluxes were studied in rats treated with S. typhimurium enterotoxin (S-LT). There was net absorption of Na+ and Cl- in the control group, while in the toxin treated animals there was net secretion of Na+ and Cl- (P less than 0.001). There was no change in the transport of D-glucose in the toxin treated group as compared to the control animals. The Na+, K(+)-ATPase pump was unaltered in the S-LT treated animals (198.67 +/- 11.23 nmoles Pi/mg protein/min) as compared to the control group (189.93 +/- 10.09 nmoles Pi/mg protein/min). There was no change in the unidirectional fluxes of Ca+2 in the S-LT treated animals as compared to the control animals, suggesting no change in the permeability of the S-LT treated intestinal membrane to Ca+2.

Studies on the mechanism of Salmonella typhimurium enterotoxin-induced diarrhoea

The unidirectional fluxes of Na+ and Cl- were studied in Salmonella typhimurium enterotoxin-treated rats. There was net secretion of Na+ and Cl- in toxin-treated animals, while in control animals there was net absorption of these ions. In the presence of the Ca(2+)-ionophore, there was net secretion of Na+ and Cl- in the control group, while the ionophore enhanced the secretion of these ions in experimental animals. The calcium channel blocker, verapamil, decreased the secretion induced by salmonella toxin, but could not reverse the secretion to absorption. There was no difference in the net absorption of Ca2+ in both the control and experimental animals. There was a significant increase in the intracellular free calcium concentrations in enterocytes isolated from toxin-treated rat intestines as compared to that in enterocytes isolated from control animals. In the presence of PMA (phorbol-12-myristated-13-acetate) there was net secretion of Na+ and Cl- in the control group, while in the experimental group there was no change in the fluxes of these ions. The selective, potent inhibitor of protein kinase C, H-7 (1-(5-isoquinolinylsulphonyl)-2-methylpiperazine) reversed the secretion of Na+ and Cl- in the toxin-treated group to absorption. The addition of indomethacin also inhibited the secretion induced by salmonella toxin, but failed to reverse it to absorption. However, the addition both H-7 and indomethacin to the experimental group had a partial additive effect. These studies demonstrate that the Salmonella enterotoxin-mediated fluid secretion involves protein kinase C and the arachidonic acid metabolites and perhaps does not involve the extracellular calcium pools.

The correlation of biochemical virulence factors and enterotoxin production with LD50 of Salmonella typhimurium in mice

Five strains of Salmonella typhimurium were examined to determine the parameters of virulence. The virulent species significantly resisted the macrophage bactericidal activity (p less than 0.05). The chemiluminescent (CL) response was studied to determine the level of Oxygen-free radicals (OFR) generated and the antioxidant enzymes superoxidase dismutase (SOD), catalase and glutathione peroxidase were assayed to determine the antioxidant mechanism of S. typhimurium to subvert these microbicidal pathways. The levels of the various enzymes were correlated with the virulence (as determined by LD50) and the ability of the microorganisms to induce diarrhoea. Oxygen free radical (OFR) generation elicited by macrophages, in the presence of virulent and avirulent salmonellae was not statistically significant (p greater than 0.05). No correlation was found between the levels of the antioxidant enzymes and the LD50 values. Thus the oxygen-dependent pathways do not appear to play a role in the pathogenesis of salmonellosis, and do not specify the virulence of the microorganism. Immunological and biological assays revealed the virulent strain to be more toxigenic than the avirulent strain. Therefore, the basis of differing virulence in S. typhimurium may be the ability to make and release more toxin in vivo.

Role of oxygen dependent mechanisms in virulence of Salmonella typhimurium

Catalase and superoxide dismutase (SOD) activities of five strains of S. typhimurium, namely SF 1546 LT2 71, SF 1835 C5 50, 386 SF 1591 Ra 20, SF 1567 Rd1, and an Indian strain were determined and correlated with their virulence profile. All five Salmonella strains exhibited catalase and SOD activities. No correlation was observed between either SOD and/or catalase activity and LD50 values of the isolates. Oxygen free radical generation elicited by macrophages, in the presence of virulent and avirulent salmonellae was also not statistically significant (P greater than 0.05), although the virulent species significantly resisted the macrophage bactericidal activity (P less than 0.05). It appears, therefore, that oxygen-dependent bactericidal mechanisms may not be important in phagocytic killing of S. typhimurium.

Catecholamine-induced experimental cardiomyopathy--a histopathological, histochemical and ultrastructural study

An experimental model of myocardiopathy was induced in rhesus monkeys following noradrenaline (NA) infusion (20 ug/kg body wt/minute), for a period of 2 hours daily for three consecutive days. The animals were sacrificed after two hours (acute phase), forty-eight hours (sub-acute phase) and twenty-one days (chronic phase). Focal depletion of succinic dehydrogenase, increase in adenosine triphosphatase, acid phosphatase and appearance of large fat droplets in myocardial muscle was noted in the acute phase. Histopathological examination revealed focal edema, opacity and fuchsinorrhagia of the muscle fibres distributed in both the ventricles. Myofibrillar degeneration, myocytolysis and vacuolization with aggregation of lymphomononuclear cells were the significant features in the acute phase. During sub-acute and chronic phases, these features became less prominent and reparative changes with proliferation of fibroblasts became more marked. By the twenty-first day, irregular, focal scars replaced the necrosed myocardium. Ultrastructurally, heart muscle showed myofibrillar disorganisation, distortion of Z and A bands, dilatation of sarcoplasmic reticulum and swelling and rupture of mitochondria. Altered membrane permeability was evidenced by the presence of reaction products of horseradish peroxidase within the cardiac cells. In the reparative phase, however, myocytolytic changes regressed and collagen deposition was the prominent feature. This experimental study has several histological features simulating human cases of myocardial infarction without coronary occlusion.

Clonidine suppression test--an evaluation of its diagnostic significance in hypertensive patients

The Clonidine Suppression Test (CST) was performed in 8 patients with Labile hypertension (Group I), 8 patients with mild and moderate Essential hypertension (Group IIa), 8 patients with severe Essential hypertension (Group IIb) and 6 patients with pheochromocytoma (Group III). The mean plasma catecholamine (CA) levels as estimated by a Spectrofluorimetric method were significantly reduced 3-4 hours after administration of clonidine (5 micrograms/kg) by mouth in Group I, IIa & IIb patients. Plasma norepinephrine levels fell from 1.82 +/- SEM 0.35 ng/ml to 1.03 +/- 0.11 ng/ml (p less than 0.05) in Group I, 1.64 +/- 0.36 ng/ml to 0.88 +/- 0.12 ng/ml (p less than 0.025) in Group IIa, 1.23 +/- 0.16 ng/ml to 0.86 +/- 0.12 ng/ml (p less than 0.005) in Group IIb patients. Plasma epinephrine levels fell from 0.35 +/- 0.06 ng/ml to 0.16 +/- 0.03 ng/ml (p less than 0.05) in Group I, 0.34 +/- 0.04 ng/ml to 0.22 +/- 0.03 ng/ml (p less than 0.01) in Group IIa, 0.33 +/- 0.06 ng/ml to 0.18 +/- 0.03 ng/ml (p less than 0.025) in Group IIb patients. The blood pressure and heart rate showed a similar response. By contrast, in patients with pheochromocytoma, the mean plasma CA levels did not show any significant fall, and even rose during the CST, but, when repeated post-operatively, showed normal suppression. No serious side effects were noticed. We conclude that the CST is a safe and reliable test for the diagnosis of pheochromocytoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Purification and characterization of a serine protease (esterase B) from rat submandibular glands

A new protease has been purified to homogeneity from rat submandibular gland homogenate by using DEAE-Sephadex chromatography, chromatofocusing, aprotinin-Sepharose affinity chromatography, and high-performance liquid chromatography. The enzyme has been named esterase B, since it represents the second major esterolytic peak on DEAE-Sephadex chromatography of submandibular gland homogenate. It is an acidic protein (pI = 4.45) with an apparent molecular weight of 27 000. It is heat-stable and has an optimum pH of 9.5. Esterase B hydrolyzed the synthetic substrates tosyl-L-arginine methyl ester and Val-Leu-Arg-p-nitroanilide (S2266). It also cleaved dog plasma kininogen to produce a kinin, identified as bradykinin on reverse-phase high-performance liquid chromatography. Esterase B, however, is only a weak kininogenase, since it had only 5% of the kininogenase activity of equimolar concentrations of glandular kallikrein and had no effect on rat mean blood pressure or on the isolated rat uterus. Esterase B activated plasminogen and had caseinolytic activity. It was inhibited by aprotinin, soybean trypsin inhibitor, lima bean trypsin inhibitor, phenylmethanesulfonyl fluoride, antipain, leupeptin, and p-tosyl-L-lysine chloromethyl ketone. On double immunodiffusion, when reacted with kallikrein and tonin antisera, esterase B showed partial identity with kallikrein but not with tonin. On immunoelectrophoresis against kallikrein antisera, esterase B formed a precipitin arc at a position different from that of kallikrein. Esterase B appears to be a trypsin-like serine protease having some homology with glandular kallikrein.

Characterization of monoclonal antibodies against rat glandular kallikrein

Monoclonal antibodies can be produced in large amounts, are homogenous and can be highly purified. A specific monoclonal antibody against glandular kallikrein could be very useful in studies of the kallikrein-kinin system, both in vivo and in vitro. Two monoclonal antibodies against rat glandular kallikrein (rgKK) were produced by immunized mouse spleen and lymph node fusion with myeloma Ag8.653. Both antibodies, named 2E9.8 and 2E9.9, bound active 125I-kallikrein and phenylmethylsulfonyl fluoride (PMSF)-inactivated 125I-kallikrein. A radioimmunoassay (RIA) was developed with each of the antibodies using rabbit anti-mouse gamma globulin to separate bound from free 125I-rgKK. The standard curve (range 10-1000 ng/tube) was curved even when subjected to logit-log transformation. Using 3% polyethylene glycol (PEG) to assist separation of bound from free, the standard curve became straight for 2E9.8 and the RIA was more sensitive, with a binding range of 0.35-2.4 ng/tube. Both antibodies were specific for rgKK since they had negligible cross-reaction with purified proteases from the submandibular gland of the rat (tonin, esterases B and E). They did not cross-react with mouse nerve growth factor, epidermal growth factor, nor with pig pancreatic kallikrein. Antibody 2E9.9 did appear to bind some human kallikrein when tested with high concentrations of this enzyme, while 2E9.8 did not. When preincubated with purified rgKK, both antibodies prevented the enzyme from releasing kinins from semi-purified dog kininogen and from cleaving [3H]-L-arginine methyl ester (3H-TAME). These results suggested that both antibodies bind an epitope near to, and maybe including, the active site of the enzyme. Monoclonal antibody 2E9.8 appears to be specific for rgKK, can be used in a sensitive RIA, and is capable of inhibiting the enzymatic activity of kallikrein. It should prove to be useful in vivo for examining the role of kallikrein in physiological processes.