Prevalence of vitamin D deficiency in South Asia

Vitamin D, also described as 'the Sun Vitamin' is a steroid with hormone-like activity. It regulates the functions of over 200 genes and is essential for growth and development of the body. Vitamin D deficiency is quite prevalent throughout the world, but it appears to be much worse in the countries of sunny South Asia, especially among children, women and elderly. Poor diet, cultural practices of the region and poverty are some of the important reasons for vitamin D deficiency. Hypovitaminosis D [vitamin D deficiency] is considered responsible for rickets, birth defects, osteoporosis, osteoarthritis, osteomalacia, chronic pain and muscle pain. Recent research has associated vitamin D deficiency as a contributing factor in diseases, such as heart disease, hypertension, neurological disorders, autoimmune disease, depression and cancer. This paper reviews the problem of vitamin D deficiency with special reference to South Asia and recommends that education regarding adequate exposure to sunlight, proper diet and fortification of selected foodstuff with vitamin D may be helpful in reducing vitamin D deficiency in this part of the world

Ascorbic acid contents of Pakistani fruits and vegetables

Fresh fruits and vegetables are good sources of vitamin C which is known for its antioxidant and immune-enhancing effects. The objective of this study was to determine ascorbic acid [vitamin C] contents of regularly consumed fruits and vegetables available in Pakistani markets. Most commonly used fresh fruits and vegetables were homogenized in 5% trichloroacetic acid, and ascorbic acid contents in the extracts were determined using a spectrophotometric method. Banana, custard apple, orange, lemon, guava and papaya were found to be very rich in ascorbic acid. Among vegetables, capsicum [green sweet pepper], cauliflower, bittergourd, roundgourd, beetroot, spinach, cabbage and radish contained high concentrations of ascorbic acid. Chikoo, grapes, pear, apricot, peach, carrot, cucumber, lettuce and 'kakri' were found to be poor sources of ascorbic acid. Several Pakistani fruits and vegetables [pear, melon, onion, sweet green pepper, spinach, cucumber] had ascorbic acid values similar to those reported by US Department of Agriculture in these fruits and vegetables in USA. However, wide differences in vitamin C contents were also observed in certain other fruits and vegetables from these two countries. This indicates that regional varieties of fruits and vegetables could vary in their ascorbic acid contents. Since subclinical deficiency of vitamin C appears to be quite common in developing countries like Pakistan, there is a need to develop awareness among masses to consume fresh fruits and vegetables with high contents of vitamin C

Deficiency of vitamin C in south Asia

Vitamin C [L-ascorbic acid] is a water soluble vitamin which is an antioxidant and has a wide variety of biological functions for growth and development of the human body. It is essential for maintaining good health. The objective of this review is to share with the scientific community, the status of vitamin C in the South Asian populations compared to other populations in the world. The focus in this review is on populations from Pakistan, India, Thailand, Malaysia, Nepal and Singapore. Mean plasma levels of vitamin C of Indians/South Asians living abroad did not vary much compared to other ethnic groups, however, there was a significant decrease in these levels among those living in Pakistan and India. In general, males, smokers, persons using drugs of abuse, individuals infected with H. pylori or parasitic infections and those with low-HDL cholesterol have lower plasma levels of vitamin C when compared to females, non-smokers and normal healthy subjects free from drugs of abuse and infections [parasitic as well as H. pylori] and having normal levels of HDL cholesterol. In winter, plasma levels of vitamin C are, generally, higher compared to summer. Availability of non-sweet fruits, namely oranges, grape fruit, guava, lime and strawberries in winter could be the reason for that. There is a positive relationship between serum haptoglobin [Hp] levels and serum vitamin C concentrations. Individuals carrying a Hp2-2 phenotype [less stable Hp] have lower levels of vitamin C. The prevalence of vitamin C deficiency [plasma levels < 2 mg/ml] is highest among Indians and people of South Asian origin compared to other races except the Mexican population. Lower intake of fresh fruits and vegetables and over-cooking of food by South Asians might contribute to the high prevalence of vitamin C deficiency in these populations. The high proportion of individuals with low levels of vitamin C in Pakistani, Indian, Malay and Chinese populations compared to most Western populations might explain higher rates of cardiovascular disease and cancer among South Asians

Plaque formation reduction with glutathione monoester in mice fed on atherogenic diet

To determine the role of glutathione monoester on reducing the development of plaque formation in an animal model. Laboratory control trial. Aga Khan University, Karachi, from January 2004 to December, 2004. Twenty-four Balb/c mice were divided into 3 equal groups. First group was fed on atherogenic diet alone, while the second group received atherogenic diet plus twice weekly injections of glutathione monoester. The third group was fed on normal diet for mice. After one year, the animals were sacrificed. Blood was analyzed for lipid levels, while liver, kidney, spleen, heart and aorta were removed to study morphological changes. In the groups of mice receiving atherogenic diet [with and without glutathione monoesters], there was significant increase in levels of total cholesterol [p=0.011] and LDL cholesterol [p=0.001] compared to levels of these lipids in mice on normal diet. However, a significant decrease in levels of triglycerides [p=0.01] was observed in the group receiving atherogenic diet along with glutathione monoester. Supplementation with glutathione monoester had the most pronounced effect only on triglyceride levels. Atherosclerotic plaques were seen in heart and/or aorta of mice receiving atherogenic diet. However, such plaques were either totally absent or if seen in an animal, were extremely small and diffuse in the group receiving glutathione monoester along with atherogenic diet. Mice on normal diet had no evidence of any plaque formation. Cholesterol granuloma was seen in liver of mice on atherogenic diet alone. In mice receiving atherogenic diet plus glutathione monoester, no cholesterol granuloma was found in liver. There were no remarkable morphological changes in spleen and kidney in the three groups of mice. Glutathione monoester appears to inhibit or reduce the development of plaque formation in mice

Variability in lipid profile before and after coronary artery bypass grafting [CCABG]

To investigate changes in total cholesterol, low density lipoprotein [LDL] cholesterol, high density lipoprotein [HDL] cholesterol, and triglycerides in serum of Pakistani patients before, immediately after and 5 days post CABG. Serum samples from 31 consecutive Pakistani angina patients undergoing CABG at the Aga Khan University Hospital were analyzed for total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides using kit methods. Immediately after CABG, there is a significant decline in the mean levels of serum cholesterol, LDL cholesterol, HDL cholesterol and triglycerides. However, 5 days post CABG, there is a significant increase in the concentrations of total cholesterol [P=0.01] and LDL cholesterol [P=0.001] in nondiabetic angina patients [n=13]. Among the diabetic group of patients [n=18], the levels of total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides went back to the pre-operative levels within 5 days post CABG. Compared to European patients, Pakistani patients tend to have very low levels of HDL cholesterol [24.9 +/- 7.1mg/dl] and high levels of triglycerides [185 +/- 50 mg/dl] on day 5 post CABG. Since risk of mortality following CABG increases with low level of HDL cholesterol and high level of triglycerides, close monitoring and treatment of high lipid levels of Pakistani patients following CABG is necessary to prevent further coronary events

Association study of the angiotensin-converting enzyme (ACE) gene G2350A dimorphism with myocardial infarction

The angiotensin converting enzyme (ACE) is a strong candidate gene for myocardial infarction (MI). Insertion-deletion dimorphism in intron 16 of this gene has been inconclusively found to be associated with it. Several new polymorphisms in the ACE gene have been identified and among these, a dimorphism in exon 17, ACE G2350A, has a significant effect on plasma ACE concentrations. To assess the value of genotyping the ACE G2350A dimorphism in a genetically homogeneous population, we carried out a case-control study of dimorphism G2350A for a putative association with MI among Pakistani nationals. We investigated a sample population of 370 Pakistanis, comprising 163 controls, and 207 patients with clinical diagnosis of acute MI (AMI). ACE G2350A alleles were visualized by assays based on polymerase chain reaction and restriction endonuclease analysis. Frequencies of G alleles were 0.68 among controls and 0.72 among AMI patients. The ACE G2350A dimorphism showed no significant association with MI (c2=0.90, 2 df, P=0.64), plasma levels of homocysteine (P=0.52) or with serum levels of folate (P=0.299). The results indicate that ACE G2350A polymorphism is not associated with risk of myocardial infarction in the Pakistani population investigated here.

Basic science education in Pakistani medical curricula: role of biochemistry and molecular biology

In Pakistan, the traditional science-oriented MBBS curriculum pertaining to basic sciences up to early seventies was loaded with the teaching of anatomy and physiology with less emphasis on biochemistry and molecular biology. Although, there has been a significant change since then, yet the role of cell and molecular biology in the curriculum has remained less than desirable. With the introduction of problem-based learning approach in some of the medical institutions of the country [the Aga Khan University and Ziauddin Medical University], the basic sciences faculty would like to ensure that the medical students are going to get sufficient exposure to cell and molecular biology, which forms the basis of the understanding of mechanisms of disease processes. The objective of this paper is to emphasize on the need to develop some common scientific learning objectives which constitute the basic concepts within the disciplines of cell and molecular biology and provide the medical students a foundation for clinical reasoning. The aim is to equip medical student with sufficient basic knowledge that is useful in any future career

N-Acetyl-beta-D-glucosaminidase in acute myocardial infarction

The objective of the study was to investigate whether the lysosomal enzyme, N-Acetyl-beta-D-glucosaminidase (NAG) activity is increased in plasma of patients with acute myocardial infarction (AMI) and to determine if there is any association between plasma levels of NAG and severity of myocardial infarction (MI). NAG activity in plasma was monitored in 69 patients with AMI and 135 normal healthy subjects using a spectrofluorimetric method. A modified Aldrich ST elevation score was used to gauge the severity of MI in terms of size of the infarct. Plasma NAG levels in AMI patients and normal healthy subjects were found to be 10.92+/-7.5 U/l and 6.8+/-2.2 U/l, respectively. These two mean value when compared by Student's t-test were significantly different P = 0.0001. No statistically significant differences in NAG activity were observed in patients in terms of gender, age, location of infarct, time from onset of chest pain to blood sampling in the hospital and size of the infarct.

Increased levels of multiple forms of dihydrofolate reductase in peripheral blood leucocytes of cancer patients receiving haematopoietic colony-stimulating factors: interim analysis

The precise mechanism whereby granulocytes proliferate when haematopoietic colony stimulating factors (CSFs) are used in neutropenic cancer patients is poorly understood. The purpose of this study was to investigate whether these cytokines bring about leucocyte proliferation by increasing the levels of multiple forms of dihydrofolate reductase (DHFR). Blood samples were collected from 36 cancer patients (25 males and 11 females) with chemotherapy-induced neutropenia. One sample of blood from each patient was obtained before therapy either with CSF, such as granulocyte colony stimulating factor (G-CSF) and granulocyte-macrophage colony stimulating factor (GM-CSF) or with placebo, and another one at the time of resolution of neutropenia. Peripheral blood leucocytes in these blood samples were counted, separated and lysed. From lysates, cytoplasmic samples were prepared and analyzed for active DHFR by a methotrexate-binding assay and for total immunoreactive DHFR by an enzyme linked immunosorbent assay. The increase in total leucocyte count (TLC) was most prominent (P < 0.005) in the CSF group and less so (P < 0.05) in the placebo group. The mean +/- SD concentration values of active DHFR before and after stimulation with GM-CSF found were to be 0.34 +/- 0.4 ng/mg protein and 0.99 +/- 0.82 ng/mg protein, respectively, and in the group treated with G-CSF, 0.24 +/- 0.32 ng/mg protein and 1.18 +/- 2.4 ng/mg protein, respectively. This increase in active DHFR after stimulation with CSF was statistically significant (P <0.05). Similarly, concentration values of immunoreactive but nonfunctional form of DHFR (IRE) were 110 +/- 97 ng/mg protein and 605 +/- 475 ng/mg protein before and after stimulation with GM-CSF, and 115 +/- 165 ng/mg protein and 1,054 +/- 1,095 ng/ mg protein before and after stimulation with G-CSF. This increase in concentration of IRE after stimulation with GM-CSF or G-CSF was statistically significant (P < 0.005). In the control group, there was an increase in the concentration of both active DHFR and IRE after treatment with placebo. However, this was not statistically significant. Resolution of neutropenia was quicker in the groups treated with CSF compared to the control group. Results of this study indicate that colony stimulating factors (G-CSF and GM-CSF) induce white cell proliferation by increasing the levels of multiple forms of DHFR.

Urinary N-acetyl-beta-D-glucosaminidase in rheumatoid arthritis

Excretion of urinary N-acetyl beta-D-glucosaminidase (NAG) and its isoenzyme patterns were studied in two groups of patients with rheumatoid arthritis (RA) and in normal control subjects. Urine samples were collected from 30 seropositive RA patients, 19 seronegative RA patients, and 15 normal healthy subjects. All the patients and normal subjects were assessed to have normal liver and kidney functions. A small portion of the urine sample was dialyzed against 0.01 M phosphate buffer, pH 7.0 and NAG activity was monitored. Mean +/- SD values of urinary NAG in seropositive RA patients, in seronegative RA patients and in normal healthy subjects were found to be 4.20 +/- 3.73 U/g creatinine, 2.96 +/- 2.11 U/gm creatinine, and 1.71 +/- 0.6 U/g creatinine, respectively. The mean urinary, NAG value in RA patients was found to be significantly higher (P < 0.05) in seropositive RA compared to the mean NAG value in normal healthy subjects and patients with seronegative RA when analyzed by one way ANOVA and Tukey-HSD test. The mean proportion of isoenzyme form B to isoenzyme form A in seropositive RA patients was also found to be significantly different (P < 0.05) from the mean proportion of these forms in normal healthy subjects and seronegative RA patients. There also appears to be a correlation between the concentration of urinary NAG and severity of the disease in seropositive RA.

Heterogeneity of methotrexate binding in human colon tumor cells

[3H]-methotrexate binding at pH 5.0 and pH 7.2 by the cytosol of tumor tissues and the surrounding normal areas of the gastrointestinal tract of patients suffering from colon or gastric cancer has been used to identify in these cells the presence of a binder of methotrexate having low-affinity for this drug in addition to the enzyme dihydrofolate reductase. Scatchard analysis of the [3H]- methotrexate binding data by a colon tumor sample also reveals that there are two binders of this drug present in the cytosol of these cells. The association constant [K[ass]] for one binder of methotrexate is = 5.6 x 10[7] M[-1] while the K[ass] for the second binder is = 1.0 x 10[6] M[-1]. The two binders do not differ very much in their apparent molecular weight. Upon isoelectric focusing, the tumor cell cytosol resolves into 4 major isoproteins each having the ability not only to bind [3H]- methotrexate but also reduce [3H]-pteroylglutamic acid to [3H]- tetrahydropteroylglutamic acid. This suggests that the two binders of methotrexate may be the two forms of dihydrofolate reductase having different affinities for this anticancer drug