Endothelial Dysfunction in Type 2 Diabetes Mellitus.

Endothelial dysfunction is an imbalance in the production of vasodilator factors and when this balance is disrupted, it predisposes the vasculature towards pro-thrombotic and pro-atherogenic effects. This results in vasoconstriction, leukocyte adherence, platelet activation, mitogenesis, pro-oxidation, impaired coagulation and nitric oxide production, vascular inflammation, atherosclerosis and thrombosis. Endothelial dysfunction is focussed as it is a potential contributor to the pathogenesis of vascular disease in diabetes mellitus. Under physiological conditions, there is a balanced release of endothelial-derived relaxing and contracting factors, but this delicate balance is altered in diabetes mellitus and atherosclerosis, thereby contributing to further progression of vascular and end-organ damage. This review focuses on endothelial dysfunction in atherosclerosis, insulin resistance, metabolic syndrome, oxidative stress associated with diabetes mellitus, markers and genetics that are implicated in endothelial dysfunction.

Association of Aberrations in One Carbon Metabolism with Intimal Medial Thickening in Patients with Type 2 Diabetes Mellitus.

The present work was aimed to study the association of one carbon genetic variants, hyperhomocysteinemia and oxidative stress markers, i.e., serum nitrite, plasma malondialdehyde (MDA) and glutathione (GSH) on intimal medial thickening (IMT) in patients with type 2 diabetes mellitus (T2D). A total number of 76 subjects from ACS Medical College and Hospital, Chennai, India were included in the study, i.e., Group I (n = 42) of T2D and Group II (n = 34) of age- and sex matched healthy controls. The glycated haemoglobin was measured by ion-exchange resin method; plasma homocysteine by Enzyme Linked Immunosorbant Assay method; serum nitrite (nitric oxide, NO), plasma MDA and GSH by spectrophotometric methods; the IMT by high frequency ultrasound. The polymorphisms of one carbon genetic variants were genotyped using polymerase chain reaction-restriction fragment length polymorphism and amplified fragment length polymorphism methods. Results indicate that methyltetrahydrofolate homocysteine methyl transferase (MTR) A2756G allele was found to be protective in T2D and the other variants were not significantly associated with T2D. Glutamate carboxypeptidase II (GCP II) C1561T (r = 0.34; p = 0.05) and methylene tetrahydrofolate reductase (MTHFR) C677T (r = 0.35; 0.04) showed positive correlation with plasma homocysteine in T2D cases. In this study, MTR A2756G allele was found to be protective in T2D; GCP II C1561T and MTHFR C677T showed positive association with plasma homocysteine in T2D cases. Among all the genetic variants, MTR A2756G was found influence IMT. RFC 1 G80A and TYMS 5'-UTR 2R3R showed synergistically interact with MTR A2756G in influencing increase in IMT.

Association of family history of type 2 diabetes mellitus with markers of endothelial dysfunction in South Indian population.

Studies indicate that risk for type 2 diabetes mellitus (T2D) or cardiovascular disease is detectable in childhood, though these disorders may not emerge until adulthood. This study was aimed to assess the markers of endothelial dysfunction in patients with the family history of T2D from South Indian population. A total of 450 subjects were included in the study comprising Group I (n = 200) of T2D, Group II (n = 200) of age- and sex-matched healthy controls, Group III (n = 25) of children of T2D patients and Group IV (n = 25) of children of healthy controls. Results showed that intimal medial thickening (IMT) was significantly higher in T2D patients, compared with control subjects with no family history of diabetes. The fasting plasma glucose, glycated hemoglobin, serum total cholesterol, triglyceride, LDL-cholesterol, apolipoprotein B (ApoB) and high-sensitive C-reactive protein (hsCRP) levels were significantly increased, whereas HDL-cholesterol and serum nitrite levels were significantly decreased in T2D patients. However, children of T2D patients who were not diabetic did not show significant increase in the IMT, as compared to those of healthy controls. In conclusion, the present study demonstrate that IMT was significantly higher in the T2D patients and increased with age and family history. The increased levels of lipids, hsCRP, IMT and decreased nitrite levels might contribute to the risk of endothelial dysfunction in patients with T2D. However, further studies are warranted with other biomarkers of endothelial dysfunction in T2D patients with increased sample size.

Whether western normative laboratory values used for clinical diagnosis are applicable to Indian population? An overview on reference interval.

Reference Intervals denote normative values related to laboratory parameters/analytes used by diagnostic centers for clinical diagnosis. International guidelines recommend that every country must establish reference intervals for healthy individuals belonging to a group of homogeneous population. Considering enormous racial and ethnic diversity of Indian population, it is mandatory to establish reference intervals specific to Indian population. The overview on reference interval describes why the national organizations in India need to initiate nationwide efforts to establish its own laboratory standards for apparently healthy reference individuals belonging to our polygenetic, polyethnic, polyracial, multilinguistic and multicultural predominantly rural and appreciable urban Indian population with varied dietary habits.

Reference intervals for serum total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides, Lp (a), apolipoprotein A-I, A-II, B, C-II, C-III, and E in healthy South Indians from Andhra Pradesh.

The incidence of cardiovascular and cerebrovascular disease is steadily increasing in South East Asian countries including Indian sub continent. Many lipids, apolipoproteins and Lp (a) except HDL-C and apo A-I, A-II are implicated as risk factors for coronary artery disease and cerebrovascular disease. There is great need to have national guidelines for each country like the ATP III guidelines recommended for U.S. population. For recommending appropriate medical decision limits, it is mandatory that each country establishes reference intervals pertaining to their population due to dietary, genetic and environmental diversity. In the present study, reference intervals for serum lipids, apolipoproteins and Lp (a) were established in a total of 1923 healthy Indian reference individuals comprising 1161 healthy men and 762 healthy women from Andhra Pradesh. For each analyte viz., serum total cholesterol, HDL-C, LDL-C, triglycerides, Lp (a), Apo A-I, Apo A-II, B, C-II, C-III and E, mean, two SD, median, confidence limits of mean, different percentile values are presented. The study also includes decade wise changes in each analyte and comparison of lipids, lipoproteins and Lp (a) among few populations covering U.S., India, Japan, Sweden, Finland and China. Reference Intervals for all lipid and lipoprotein parameters will immensely help in assessing associated risk for cardiovascular and cerebrovascular diseases in India. Additionally, the results will be beneficial in formulating our own guidelines pertaining to Indian population.

Tumour markers: An overview.

Tumor Markers comprise a wide spectrum of biomacromolecules synthesized in excess concentration by a wide variety of neoplastic cells. The markers could be endogenous products of highly active metabolic malignant cells or the products of newly switched on genes, which remained unexprssed in early life or newly acquired antigens at cellular and sub-cellular levels. The appearance of tumor marker and their concentration are related to the genesis and growth of malignant tumors in patients. An ideal tumor marker should be highly sensitive, specific, reliable with high prognostic value, organ specificity and it should correlate with tumor stages. However, none of the tumor markers reported to date has all these characteristics. Inspite of these limitations, many tumor markers have shown excellent clinical relevance in monitoring efficacy of different modes of therapies during entire course of illness in cancer patients. Additionally, determination of markers also helps in early detection of cancer recurrence and in prognostication.

Prostate specific antigen in patients of benign prostate hypertrophy and carcinoma prostate.

Prostate Specific Antigen (PSA) has emerged as the most applicable and important tumor marker for carcinoma prostate. In the present study PSA was determined in serum of healthy subjects, patients of benign prostate hypertrophy (BPH) and Carcinoma Prostate (Ca-P) to evaluate its diagnostic efficiency in day to day management of prostate cancer patients and in differentiating patients of early prostate cancer from those with BPH. Receiver operating characteristic curve (ROC) revealed 2 ng/ml and 10 ng/ml cut off serum PSA level for BPH and untreated carcinoma prostate patients (Ca-P). An extremely significant increase (P<0.0001) was observed in mean PSA concentration in BPH patients and adenocarcinoma prostate patients when compared to healthy males. Clinical relevance of PSA was highlighted by a case study of cancer patient prior to any therapy till death.

Racial and ethnic variation of PSA in global population: Age specific reference intervals for serum prostate specific antigen in healthy South Indian males.

The serum PSA is universally accepted as the useful and clinically relevant tumor marker for monitoring therapy and identifying early recurrence in patients of carcinoma prostate throughout the world. However, application of serum PSA is limited to screening for early adenocarcinoma prostate among males above fifty years of age.Serum PSA concentration varies from one population to another in different parts of the world. Many groups of workers have selected 4 ng/ml of serum PSA as upper limit of normal range without giving due consideration for age specific increase in serum PSA. There is no single report available on normal decade wise age specific reference intervals for serum PSA in Indian males.The present study is undertaken to establish age specific reference intervals in healthy Indian males from 20-89 years belonging to subpopulation of Andhra Pradesh from South India. Our results revealed lowest concentration of 95 percentile serum PSA in Indian males compared to other populations globally. Contrary to this, healthy Afro Americans were found to have highest concentration of serum PSA compared to all other populations.

Stability of total and free prostate specific antigen in serum samples at different storage conditions.

The present preliminary study was performed to find out stability of total prostate specific antigen (PSA) and free prostate specific antigen (FPSA) in serum of healthy males as well as in patients of benign and malignant disorders of prostate at various freezing and nonfreezing temperatures and at different duration of time.The results of our study indicated long-term stability of both the analytes in frozen serum. Serum total and free PSA were stable only for three to four days in regular refrigerators in unfrozen states. Clotted blood kept at room temperature (25°C-30°C) did not cause change in concentrations of both the analytes for twenty four hours.

An overview of monoclonal gammapathies.

The neoplastic proliferation of single clones of plasma cells causes synthesis of very large amount of monoclonal immunoglobulins consisting of only one type of heavy either the gamma, alpha, mu, delta or epsilon chain or only kappa or lambda light chains. Each monoclonal immunolobulin differs idiotypically from each other. These monoclonal immunoglobulins are also called paraproteins and are frequently associated with a broad heterogeneous group of plasma cell dyscrasias. Occasionally their presence is observed in a few benign conditions and in old age. In the present review a detailed account of different types of monoclonal gammapathies are described.

Spectrum of monoclonal gammapathies in Andhra Pradesh.

In the present study, monoclonal gammapathy was identified in a total of 245 patients of plasma cell dyscrasias during period of 1987 to 2000. The monoclonal band was identified in serum by agar gel electrophoresis in all the cases and in urine in a few cases. Characterization of paraprotein (monoclonal immunoglobulin class and light chain type) was carried out by employing immunoelectrophoresis and/or immunofixation electrophoresis using heavy chain specific gamma, alpha, mu, delta and epsilon and light chain specific kappa (K), lambda (λ) antisera. Serum immunoglobulins Ig G, Ig A, and Ig M were estimated by immunoturbidometry. Serum urea, creatinine, uric acid, alkaline phosphatase, total proteins, albumin, calcium and phosphorus were estimated by using routine biochemical methods. Among the 245 cases, 73.1% monoclonal gammapathies were of secretory type and 7.3% were non-secretory. Monoclonal gammapathies were associated with 80.4% of multiple myeloma, 8.9% of solitary plasmacytoma, 4.1% of extra-medullary plasmacytoma, 3.3% of lymphoma and 2.9% of plasma cell leukemia. Classification of secretory monoclonal immunoglobulin revealed monoclonal immunoglobulin Ig G in 74%, Ig A 15% and Ig M in 2.9% cases.

Application of tumor markers in ovarian malignancies.

Ovarian cancer is the fifth leading cause of death in women. The incidence of this malignancy increases in women over the age of 40. The overall five years survival is less than 30%, as most women present with advanced stage disease. Until recently, detection of early stage ovarian cancer has been difficult since it is usually nonpalpable and asymptomatic. The definitive diagnosis of an ovarian mass is a common problem in gynecologic patients with adnexal mass. The routine standard evaluation for adnexal masses includes patient's history, physical examination, ultrasound and histopathological examination. These parameters individually or in combination have little predictive value. The accuracy of diagnostic tools are of immense value and great concern to practicsing Gynecologists and Oncologists. The clinical application of serum concentration of CA 125, AFP and hCG is of great help not only as diagnostic aid but also in monitoring efficacy of any treatment modality like chemotherapy, radiotherapy or surgical resection. Additionally, evaluation of tumor marker concentration helps in predicting early biochemical recurrence and in prognostication in different types of ovarian malignancies. The ability to differentiate a malignant mass from a benign pelvic mass pretherapeutically could be enhanced optimally by additional use of tumor markers such as cancer antigen CA-125, alphafetoprotein and human chorionic gonadotrophin in pre-and postmenopausal women.

Cardioprotective effect of magnesium chloride in experimental acute myocardial infarction.

Cardioprotective role of intravenous administration of magnesium chloride was evaluated in rabbits by biochemical and histopathological parameters. Myocardial damage was induced by injecting (i.v.) isoprenaline 1, 2.5, 5 and 7.5 mg/kg body weight of animal. There was a dose dependent increase in the activity of cardiac enzyme creatinine kinase CK (C Max). Maximal elevation of CK (C Max) was observed with 2.5 mg isoprenaline. The mean T-max (mean of the time duration in hr at which maximum creatinine kinase activity of individual rabbit was observed in a group) shifted early, significantly with 2.5, 5 and 7.5 mg isoprenaline compared to control group. Histopathologically, myocardial damage was quite significant in 2.5 mg isoprenaline subgroup of animals. A mortality of 29% was observed in animals injected with 5 and 7.5 mg isoprenaline, whereas all animals subjected with 1 and 2.5 mg isoprenaline were alive for 72 hr. Considering the data on serial determination of cardiac enzyme CK and histopathological changes, 2.5 mg isoprenaline was chosen as standard dose to study efficacy of cardioprotection by gold standard verapamil and magnesium chloride. Verapamil (5 microM) injected prior to 2.5 mg isoprenaline administration revealed significant reduction of CK (C Max) activity (P < 0.05) compared to animals infused with isoprenaline alone. T-max value did not show any alteration in both the groups. Histopathological findings showed no areas of necrosis and cellular infiltrates in animals primed with 2.5 mg isoprenaline following verapamil. Highly significant reduction in CK (C-max) activity was observed in animals administered with 40 mg magnesium chloride prior to isoprenaline compared to animals treated with isoprenaline alone (P < 0.001). In addition to this, significant delay in T-max of CK activity was observed in group treated with 40 mg magnesium chloride and isoprenaline compared to group treated with only isoprenaline (P < 0.01). The study clearly highlighted and confirmed the valuable role of magnesium chloride as cardioprotective agent.

Differential reduction in the expression of keratin polypeptides in human gastric carcinomas.

Phenotypic expression of keratin polypeptides is known to be dependent on various factors, one of which is malignant transformation. In this study, we compared the pattern of expression of keratin polypeptides between control and malignant gastric tissues by employing different morphological and biochemical techniques. The results indicated preferential decrease of acidic keratin polypeptides in malignant gastric tissues. The nonmalignant gastric tissues expressed four keratin polypeptides-two acidic and two basic-whereas in the gastric adenocarcinomas expression of only two basic polypeptides was observed. Marked variation of keratin expression between the control and malignant gastric tissues not only highlights its clinical value as a support to diagnosis but also elucidates the underlying changes due to malignant transformation.

Clinical relevance of alphafetoprotein microheterogeneity in alphafetoprotein-secreting tumors.

The importance of the oncofetal glycoprotein antigen alphafetoprotein (AFP) as a tumor marker is well documented. Structural heterogeneity of AFP molecules due to its associated carbohydrate moieties has also been demonstrated. In the present study, molecular variants of AFP, Concanavalin A reactive (R Con A) and Concanavalin A nonreactive (NR Con A) were quantified in five cases of hepatocellular carcinoma (HCC), three cases of hepatoblastoma, five gonadal and two extragonadal germ cell tumors, and two suspected liver secondaries by employing crossed immunoaffino electrophoresis (CIAE). AFP peaks were localized using anti-AFP antibodies conjugated to alkaline phosphatase. Characteristic patterns of AFP R Con A and NR Con A fractions were obtained in different AFP-secreting malignancies. Serum samples of HCC and hepatoblastoma were predominantly composed of R Con A AFP, while gonadal and extragonadal germ cell tumors showed significant reduction of R Con A AFP and elevation of NR Con A AFP. Analysis of AFP variants in sera from two patients of suspected liver metastasis with elevated AFP confirmed liver secondaries arising from germ cell tumor in one patient and HCC in the other patient. The present study highlights the importance of AFP microheterogeneity analysis not only as diagnostic aid for the differential diagnosis of AFP-secreting tumors, but also in providing better management and prognosis.

The dependence of glycosyltransferases in Dictyostelium discoideum on the structure of polyisoprenols.

Mannosyltransferases in plasma membranes of Dictyostelium discoideum synthesize polyisoprenylphosphomannosides from exogenous polyisoprenylphosphates and GDP-mannose. The specificity of the enzymes depends on the chain length and the saturation of the polyisoprenols. Maximum activity is reached by a alpha-saturated C-55 polyisoprenylphosphate.