An outbreak of influenza A (H3N2) in Delhi, 1993

An outbreak of Influenza A, subtype H3N2 occurred in Delhi during July-August, 1993. Both urban and rural areas were affected. Attack rates in children and adults were found to be similar; the mean age of patients from whom the virus was isolated was found to be 21 years. The disease was of acute onset, mild in nature and about one week in duration. Main symptoms included fever, chills, cough, sore throat, bodyaches, backache and headache. Complications were absent. About 82 per cent of the affected house-holds had only a single case. Influenza A subtype H3N2 virus was isolated from 12 of 15 throat swabs collected from PUO cases.

Management of dyslipidemia in IDDM patients

Patients with insulin-dependent diabetes mellitus (IDDM) are at an increased risk for coronary heart disease. Factors that may enhance the risk include dyslipidemia, hypertension, and hyperglycemia. Until recently, the importance of dyslipidemia in IDDM was ignored because the prevalence of high cholesterol levels was similar to that in the nondiabetic population. However, unique abnormalities in the composition and metabolism of lipoproteins may occur in IDDM patients. Management of IDDM patients, therefore, should include control of dyslipidemia as well as control of hyperglycemia and hypertension. The therapeutic goals for serum cholesterol reduction in IDDM patients should be lower than that for nondiabetic patients, and the goals for children should be even lower than those for adults. Both very-low-density lipoprotein and low-density lipoprotein (LDL) levels should be the targets for therapeutic interventions and not just the LDL alone. Because of the unique features of dyslipidemia in IDDM patients, the therapeutic options may not be the same as that for nondiabetic patients. Hyperglycemia should be controlled by matching daily energy intake and activity with appropriately timed doses of insulin. The diets should be low in saturated fats and cholesterol. If dyslipidemia persists despite diet and hyperglycemia management, drug therapy may be initiated. For IDDM children > or = 10 years of age with elevated LDL-cholesterol levels, the first-line therapy should be bile acid sequestrants. For adults with IDDM, bile acid sequestrants also may be the drugs of choice, particularly for normotriglyceridemic patients. Nicotinic acid therapy should be avoided. Among other drugs, hydroxymethyl-glutaryl coenzyme A reductase inhibitors may be preferable for patients with elevated LDL cholesterol and borderline hypertriglyceridemia. Fibric acid derivatives should be used for markedly hypertriglyceridemic patients. The role of probucol for dyslipidemia in IDDM patients is not clear.

Expression of biomarkers for transformation in 7,12-dimethylbenz[a]anthracene-treated mammary epithelial-cells

The ability of the mammary procarcinogen 7,12-dimethylbenz(a)anthracene (DMBA) to induce the expression of selected molecular and cellular biomarkers for preneoplastic transformation is examined in a newly developed, immortalized but nontumorigenic mammary epithelial cell line C57/MG. This cell line is established from the mammary tissues of virgin female C57BL/6J strain of mouse. The biomarkers examined included: DMBA-DNA adduct formation and DNA repair (molecular markers), and anchorage-dependent and anchorage-independent growth (cellular markers). Log phase cultures of C57/MG cells were treated for 24 h with 2, 20, and 200 ng/ml of DMBA, and were assayed for DNA adduct formation by the P-32-postlabeling, for DNA repair by the hydroxyurea (HU)-insensitive H-3-thymidine uptake, and for anchorage-dependent and anchorage-independent growth by colony forming efficiency in adherent and non-adherent conditions, respectively. A DMBA dose-dependent increase was detected in DNA adduct formation ranging from 6 adducts/10(9) nucleotides at 2 ng/ml to >1600 adducts/10(9) nucleotides at 200 ng/ml DMBA concentration and in induction of DNA repair synthesis ranging from 10 to 251%. The colony forming efficiency in adherent and non-adherent conditions, exhibited progressive increase up to the dose of 200 ng/ml of DMBA. These results indicate that C57/MG cells are capable of metabolizing the procarcinogen DMBA to generate DNA adducts which may, in part, be responsible for the aberrant proliferation. These molecular and cellular biomarkers that are expressed prior to tumorigenesis may thus constitute useful endpoints for preneoplastic transformation.

Revised NIOSH equation for the design and evaluation of manual lifting tasks

In 1985, the National Institute for Occupational Safety and Health (NIOSH) convened an ad hoc committee of experts who reviewed the current literature on lifting, recommend criteria for defining lifting capacity, and in 1991 developed a revised lifting equation. Subsequently, NIOSH developed the documentation for the equation and played a prominent role in recommending methods for interpreting the results of the equation. The 1991 equation reflects new findings and provides methods for evaluating asymmetrical lifting tasks, lifts of objects with less than optimal hand-container couplings, and also provides guidelines for a larger range of work durations and lifting frequencies than the 1981 equation. This paper provides the basis for selecting the three criteria (biomechanical, physiological, and psychophysical) that were used to define the 1991 equation, and describes the derivation of the individual components (Putz-Anderson and Waters 1991). The paper also describes the lifting index (LI), an index of relative physical stress, that can be used to identify hazardous lifting tasks. Although the 1991 equation has not been fully validated, the recommended weight limits derived from the revised equation are consistent with or lower than those generally reported in the literature. NIOSH believes that the revised 1991 lifting equation is more likely than the 1981 equation to protect most workers.

Homocystinuria: a family with peculiar genetic transmission

Homocystinurias are a relatively rare group of seven distinct genetic disorders of amino acid metabolism characterised by increased concentration of sulphur containing amino acid homocysteine in the blood and urine. Its transmission is believed to be autosomal recessive. We reported a family with four females siblings spared and three male siblings affected. This case is reported because of its rarity and peculiar genetic transmission.

Interception of reactive, DNA adduct-forming metabolites present in rodent serum following carcinogen exposure: implications for use of body fluids in biomonitoring

The detection of adduct-forming metabolites in the serum of carcinogen treated animals by 32P-postlabeling was evaluated as a novel approach to overcome the stringent requirement of obtaining DNA from tissues in human biomonitoring assessments. Benzo[a]pyrene (BP) was given i.p. to B6C3F1, C57B1/6, ICR, and DBA/2 mouse strains as well as Sprague-Dawley rats. Three adducts related to BP were detected in the liver and/or lung of Sprague-Dawley rats or B6C3F1, C57B1/6, and ICR mice; a single adduct was detected in the liver and lung of the DBA/2 mouse strain. Adducts chromatographically similar to those found in these tissues were also detected when salmon sperm DNA was incubated with the serum of BP-treated animals. Benzidine treatment induced the formation of one adduct in the liver of B6C3F1 mice, which was chromatographically similar to dG-C8-N'-acetylbenzidine. An identical adduct was detected in the salmon sperm DNA incubated with the serum of these mice. Cyclopenta[cd]pyrene treatment produced four major and three minor adducts in the liver or lung of B6C3F1 mice, all but two of which were detected in DNA incubated with serum of cyclopenta[cd]pyrene-treated animals. Large interstrain differences in the serum level of BP adduct-forming metabolites as well as tissue DNA adducts were found which correlated with previously observed strain-specific trends in sensitivity to PAH-mediated carcinogenesis. Thus, levels of BP adduct-forming metabolites were found in the following descending order: B6C3F1, C57B1/6, ICR, and DBA/2. BP-derived adduct-forming metabolites were detectable as late as 2 d and 5 d post-treatment in the serum of C57B1/6 mice or Sprague-Dawley rats, respectively, which seems to coincide well with the reported species-specific turnover of serum albumin; a protein know to be involved in the transport of reactive metabolites throughout the systemic circulation. The results obtained clearly indicate the presence of adduct-forming carcinogen metabolites in the serum of treated animals, which seemingly irrespective of their chemical nature, can be intercepted with exogenous DNA and detected by 32P-postlabeling. Successful application of a serum-based approach coupled with the use of the generally applicable, ultrasensitive 32P-postlabeling assay could evade the need for obtaining DNA from tissues, currently the major impediment in human biomonitoring studies.

Effect of high carbohydrate intake on hyperglycemia, islet function, and plasma lipoproteins in NIDDM

OBJECTIVE

To study effects of high carbohydrate intake on hyperglycemia, islet functions, and plasma lipoproteins in patients with NIDDM.

RESEARCH DESIGN AND METHODS

An attempt was made to induce hyperglycemia in 10 men with NIDDM by feeding them an isocaloric high-carbohydrate diet (65% of energy as simple carbohydrates [31% as glucose] and 20% as fat) for 28 days in a metabolic ward. Response to the high-carbohydrate diet was compared with that of feeding a diet rich in monounsaturated fat (45% of energy as fat [31% as monounsaturated fat] and 38% as carbohydrates) for 28 days in a cross-over manner. Islet functions were assessed by evaluating plasma glucose, insulin, C-peptide and glucagon responses to standard meal tolerance tests on days 0, 14, 21, and 28 of each dietary period. Fasting plasma lipoproteins were determined during the last week of each dietary period.

RESULTS

The high-carbohydrate diet caused significant but modest accentuation of hyperglycemia, particularly in patients with moderately severe diabetes mellitus, whereas no change was observed with the high-monounsaturated fatty-acid diet. Accentuation of hyperglycemia was accompanied by an increase in plasma glucagon levels, but no significant change in insulin and C-peptide responses. In 1 patient, feeding the high-carbohydrate diet for 68 days produced marked hyperglycemia and caused definite suppression of insulin and C-peptide responses along with an increase in glucagon levels. Compared with the high-monounsaturated fat diet, the high-carbohydrate diet also raised plasma triglyceride and VLDL cholesterol concentrations.

CONCLUSIONS

High-carbohydrate diets may cause accentuation of hyperglycemia and a rise in plasma glucagon levels in NIDDM patients. High-carbohydrate diets also adversely affect lipoproteins and therefore may not be desirable in all NIDDM patients.

Lipid-lowering therapy and macrovascular disease in diabetes mellitus

Patients with diabetes mellitus are at increased risk of morbidity and mortality from macrovascular disease manifesting as coronary heart disease, cerebrovascular accidents, and peripheral vascular disease. Increased frequency of dyslipidemia, hyperglycemia, obesity, hypertension, and associated nephropathy may contribute to accelerated atherogenesis in diabetic patients. Therefore, besides intensive control of hyperglycemia, management of dyslipidemia, hypertension, and obesity should also be emphasized in diabetic patients. Those who smoke should be strongly encouraged to quit smoking. Besides attempts to achieve normal levels of plasma lipoproteins, consideration also should be given to normalization of compositional abnormalities of various lipoproteins in patients with diabetes mellitus. The therapeutic goals for cholesterol reduction should be lower in diabetic patients than nondiabetic subjects. The first step is to achieve good metabolic control of diabetes mellitus by diet, exercise, and weight reduction and, if needed, with sulfonylureas or insulin therapy. Because most of the patients with insulin-dependent diabetes mellitus achieve normal levels of plasma lipoproteins with intensive insulin therapy, lipid-lowering medications are rarely needed. In patients with non-insulin-dependent diabetes mellitus, however, dyslipidemia often persists despite good glycemic control. Lipid-lowering medications should be considered in such patients. Because nicotinic acid can cause marked deterioration in glycemic control, and bile acid-binding resins may accentuate hypertriglyceridemia, these agents are less desirable for use by diabetic patients. Inhibitors of hydroxymethylglutaryl coenzyme A reductase may be preferred in patients with elevated LDL cholesterol and mld hypertriglyceridemia. For diabetic patients with marked hypertriglyceridemia, however, fibric acid derivatives should be the drug of choice.

Comparison of effects of high and low carbohydrate diets on plasma lipoproteins and insulin sensitivity in patients with mild NIDDM

Previous studies indicate that diets rich in digestible carbohydrates improve glucose tolerance in nondiabetic individuals, but may worsen glycemic control in NIDDM patients with moderately severe hyperglycemia. The effects of such high-carbohydrate diets on glucose metabolism in patients with mild NIDDM have not been studied adequately. This study compares responses to an isocaloric high-carbohydrate diet (60% of total energy from carbohydrates) and a low-carbohydrate diet (35% of total energy from carbohydrates) in 8 men with mild NIDDM. Both diets were low in saturated fatty acids, whereas the low-carbohydrate diet was rich in monounsaturated fatty acids. The two diets were matched for dietary fiber content (25 g/day). All patients were randomly assigned to receive first one and then the other diet, each for a period of 21 days, in a metabolic ward. Compared with the low-carbohydrate diet, the high-carbohydrate diet caused a 27.5% increase in plasma triglycerides and a similar increase in VLDL-cholesterol levels; it also reduced levels of HDL cholesterol by 11%. Plasma glucose and insulin responses to identical standard breakfast meals were studied on days 4 and 21 of each period, and these did not differ significantly between the two diets. At the end of each period, a euglycemic hyperinsulinemic glucose clamp study with simultaneous infusion of [3-3H]glucose revealed no significant changes in hepatic insulin sensitivity; and peripheral insulin-mediated glucose disposal remained unchanged (14.7 +/- 1.4 vs. 16.5 +/- 2.3 microM.kg-1.min-1 on the high-carbohydrate and low-carbohydrate diets, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention strategies and the low back in industry

Several different approaches have been tried in industry to prevent low-back injuries. The scientific literature shows that only job-specific strength testing and ergonomic job design are partially effective in preventing low-back injuries. Job-specific strength testing is supported as a means of identifying high-risk workers who need to perform manual materials handling. However, this approach should be carefully validated for its effectiveness before it is used as a form of selection procedure. At present, ergonomic job design offers the most potential for preventing disabling low-back injuries and other musculoskeletal injuries. Quantitative and objective methods (such as NIOSH guidelines, biomechanical models, energy expenditure, and strength data) are available to analyze a given job and to determine the relative risk of an injury.

Occupational biomechanics and low-back pain

The basic principles of biomechanics are introduced and explained as they relate to the field of ergonomics, especially regarding the lumbar spine. The discussion is organized into the following sections: biomechanics--an overview, spinal structures and loading, biomechanical basis for low-back pain, compressive strength of the lumbar spinal column, biomechanical models, intra-abdominal pressure, lifting technique, and practical applications. The conclusion lists nine guidelines for understanding the internal stresses placed on the lower back by lifting and thereby for avoiding low-back injuries in the workplace.

Epidemiology of low-back pain in industry

Low-back pain and back injuries are of such a complex nature that any one criterion cannot be applied by itself to give a valid assessment of the risk associated with manual materials-handling jobs. There is no question that low-back pain is an extremely significant cause of disability and has a major socioeconomic impact, but many different personal and job factors are associated with the incidence and prevalence of these complaints. There is a need for ongoing systematic investigations of the multiple risk factors that may be causally related to low-back pain and may possibly be amendable to preventive interventions. Knowledge of workplace and individual risk factors is far from complete. Prospective studies are needed so that factors contributing to the development of low-back pain can be separated from factors resulting from low-back pain. It is difficult to relate low-back pain to the workplace because it occurs quite often in workers employed in sedentary occupations. However, incidence, severity, and disability are all related to the physical demands of the job. In this regard, jobs involving lifting, lowering, pushing, pulling, carrying, and holding; body movements such as frequent bending, twisting, and sudden movements; and working in bent-over postures appear to have a significant potential for producing low-back pain. A combination of lifting, bending, and twisting appears to be most hazardous. It is concluded that lifting heavy loads contributes to increased frequency and severity rates for low-back pain. This is true regardless of whether the lifting is performed over a short period or throughout the day and whether it is performed a few times per day of repetitively. If, however, such lifting is performed repetitively, the medical hazard extends beyond low-back problems to other musculoskeletal strain and sprain injuries and to fatigue-related injuries, particularly for weaker workers. In this latter regard, gender, age, anthropometry, and previous history of back pain are known to modify these risks for populations of workers. The inherent variability between workers and within any worker over time precludes the use of such factors to assign risk to any particular individual.

Peculiar distribution of adipose tissue in patients with congenital generalized lipodystrophy

Congenital generalized lipodystrophy (CGL) is a rare genetic disease with extreme paucity of fat from birth which is believed to be generalized, involving the whole body. Affected patients are characterized by severe insulin resistance. Sites of adipose tissue distribution in patients with CGL have not been studied systematically. Therefore, the fat distribution in three women (17-20 yr old) with CGL was investigated. Determination of body composition by underwater volume displacement suggested the complete absence of body fat (range, -3 to -7%; normal, 15-25%). Whole body magnetic resonance imaging, however, detected fat in particular anatomical sites, namely in orbits, palms and soles, and periarticular and epidural regions. Some fat was also localized in the tongue, breasts, vulva, and buccal area. Fat in other subcutaneous areas, intraabdominal and intrathoracic regions, and bone marrow was essentially absent. Thus, patients with CGL do not have a complete absence of body fat; of interest, fat is present in those sites where adipose tissue may be serving mainly a mechanical function. Patients with CGL, therefore, provided a unique opportunity to identify the various sites of localization of "mechanical" adipose tissue in the human body. Our study suggests that the genetic defect in CGL results in poor growth and development of metabolically active adipose tissue, whereas mechanical adipose tissue is well preserved.