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Biomedical subjects

D Chopra

Publications and source records attributed to D Chopra.

13 recordsLinked to original sources
PubMed1994

Modeling and optimising lactose fermentation using a fluorosensor.

Lactose has been fermented in a Tokyo Rikakikai Fermentor using two percent seeding at various temperatures. The progress of the reaction was followed by measuring the fluorescent signal due to NADH with a Dr. Ingold (Switzerland) fluorosensor which has an excitation wave length of 360 nm and measurement wavelength of 450 nm. The optimum temperature for this fermentation reaction is 34 degree celsius. At this temperature while biomass growth rate and final biomass concentration are a maximum the time taken to reach the final biomass concentration and lag time are a minimum. The fluorescent voltage vs time data fitted a first order plus dead time model with an error of less than one percent. The present work is in good agreement with earlier work on glucose and lactose fermentation with one percent seeding. The increase in seeding from one to two percent has improved the optimum parameters studied. Further work on higher seeding concentration and higher order models is in progress.

Fermentation↗
PubMed1992

Elevated serum dehydroepiandrosterone sulfate levels in practitioners of the Transcendental Meditation (TM) and TM-Sidhi programs.

Serum dehydroepiandrosterone sulfate (DHEA-S) levels were measured in 270 men and 153 women who were experienced practitioners of the Transcendental Meditation (TM) and TM-Sidhi programs, mental techniques practiced twice daily, sitting quietly with the eyes closed. These were compared according to sex and 5-year age grouping to 799 male and 453 female nonmeditators. The mean DHEA-S levels in the TM group were higher in all 11 of the age groups measured in women and in 6 of 7 5-year age groups over 40 in men. There were no systematic differences in younger men. Simple regression using TM-group data revealed that this effect was independent of diet, body mass index, and exercise. The mean TM-group levels measured in all women and in the older men were generally comparable to those of nonmeditator groups 5 to 10 years younger. These findings suggest that some characteristics of TM practitioners are modifying the age-related deterioration in DHEA-S secretion by the adrenal cortex.

Adult↗
PubMed1987

Smith-Lemli-Opitz syndrome-type II: multiple congenital anomalies with male pseudohermaphroditism and frequent early lethality.

In 1964, Smith et al described a syndrome of microcephaly, growth and mental retardation, unusual facial appearance, syndactyly of toes 2 and 3, and genital abnormalities. Major structural malformations and early death have been uncommon in the many subsequent literature reports. We report on 19 infants with a phenotype we propose to call Smith-Lemli-Opitz syndrome (SLOS)-Type II, in which major structural abnormalities, male pseudohermaphroditism, and early lethality are common. Of these 19 patients, 18 had postaxial hexadactyly, 16 had congenital heart defect, 13 had cleft palate, and 10 had cataracts. Unusual findings seen in these patients at autopsy included Hirschsprung "disease" in five patients, unilobated lungs in six, large adrenals in four, and pancreatic islet cell hyperplasia in three. Comparison of our cases to 19 similar literature cases suggests the existence of a distinct phenotype that may be separate from SLOS as originally described. It is also inherited as an autosomal recessive, as documented by occurrence in one pair of sibs in this study and recurrence in three reported families.

Abnormalities, Multiple↗
PubMed1979

The aging thyroid. Increased prevalence of elevated serum thyrotropin levels in the elderly.

Of 344 relatively healthy persons older than 60 years, 22 (5.9%) had a clearly elevated level of serum thyrotropin (TSH) (greater than 10 muU/mL), a finding more common in women than in men. Ten of the 22 had low values for serum thyroxine (T4) and free T4 (FT4) index, but only one had a low value for serum triiodothyronine (T3) or free T3 (FT3) index. A further 14.4% had a slightly elevated level of serum TSH (greater than 5 less than or equal to 10 muU/mL), but none had low values for serum T4 or FT4 index. Age alone has little effect on the measurements of T4; age is associated with slightly lower T3 levels, but only in men 60 years or older or in women 80 years or older. Longitudinal studies should determine if a slightly elevated serum TSH rises further with age and if there is a causal relationship between a high level of serum TSH and cardiovascular disease.

Aged↗
PubMed1978

Riedel's struma associated with subacute thyroiditis, hypothyroidism, and hypoparathyroidism.

Riedel's struma with dense fibrous invasion of surrounding muscle and fat was found in a patient who had clinical subacute thyroiditis superimposed on primary hypothyroidism. Riedel's struma may sometimes be an uncommon stage in the more common subacute form of thyroiditis, although in our patient an unusual coincidence of subacute thyroiditis and Riedel's struma is also possible. Of interest in our patient was the development of spontaneous primary hypoparathyroidism; parathyroid function returned to normal concomitant with the spontaneous resolution of the goiter after partial resection. This patient also represents another instance of hyperthyroidism developing in a previously hypothyroid patient.

Female↗
PubMed1978

The free triiodothyronine (T3) index.

In a large number of normal men (n = 111) and women (n = 110) the free triiodothyronine (T3), index, calculated from serum total T3 and T3-uptake, was highly correlated with free T3, measured by equilibrium dialysis. The correlation was almost as high as that of the free thyroxine (T4) index with free T4. The correlations of the total T3, free T3, and free T3 index with, respectively, the total T4, free T4, and free T4 index were much lower, though still statistically significant. The free T3 index is clinically useful because serum total T3 may sometimes be misleading. Hyperthyroid patients with apparent T4-toxicosis and normal total T3 may have an elevated free T3 index and thus physiologically elevated levels of both thyroid hormones. Calculation of the free T3 index might also make possible the diagnosis of T3-toxicosis in a patient with a normal free T4 index and normal total T3. Total T3 may be elevated without an elevated total T4 in women taking oral contraceptives; thus the free T3 index may prevent a misdiagnosis of T3-toxicosis. The free T3 index seems no better than total T3 in the diagnosis of primary hypothyroidism, but it can confirm the diagnosis of T3-hypothyroidism.

Adult↗
PubMed1975

Hypercalcemia and malignant disease.

Virtually any malignancy may lead to hypercalcemia, but carcinoma of the breast, myeloma, and carcinoma of the lung are especially frequent offenders. A more difficult diagnostic problem is posed by the "silent" tumor which secretes a substance causing hypercalcemia. Foremost in this category are bronchogenic carcimona and hypernephroma.

Adenocarcinoma↗