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Biomedical subjects

D Schwartz

Publications and source records attributed to D Schwartz.

At least 325 records · Page 18Linked to original sources
PubMed1982

Maternal smoking and birth weight in relation to dietary habits.

A study on dietary and smoking behavior during pregnancy was performed between January, 1976, and September, 1979, at the St. Antoine Maternity Hospital in Paris. In addition to the routine clinical examinations at the third, sixth, eight, and ninth months of pregnancy, the women were systematically questioned about their dietary and tobacco habits. No dietary advice was given by the dietitians at any time, nor was there special counseling against smoking. Among 534 women who were followed up, 200 (37%) were smokers before pregnancy. At the sixth month, half of them had stopped smoking and the others had reduced their consumption. The analysis showed that the mean caloric intake and the gain in weight were the highest in the women who continued to smoke and the lowest in nonsmokers. Intermediate results were found in smokers who stopped. Birth weight was, on the average, 70 gm lower among smokers throughout pregnancy, compared with the other two groups, but this difference was not significant. These findings are consistent with the hypothesis that the negative effects of smoking on the fetus could be compensated for, to a great extent, by extra food.

Adult↗
PubMed1982

Superior vena cava syndrome in childhood and adolescence: a review of the literature and report of three cases.

Obstruction of the superior vena cava is rare in childhood and adolescence. Its etiology is now mainly iatrogenic. Mediastinal tumors are the main primary causes of the superior vena cava syndrome (SVCS) in childhood and adolescence. The most common mediastinal tumors presenting with the SVCS are the lymph node tumors and especially the lymphosarcomas. About 50% of the mediastinal tumors are primary in the mediastinum. Early treatment is designed to cause a rapid shrinking of the tumor and should not be delayed by an overly diligent pursuit of the diagnosis. Treatment should consist of a combination of radiation therapy, chemotherapy, and steroids. Surgery should be limited to obtaining tissue for diagnosis, except when the tumor is localized to the mediastinum and is completely resectable. One hundred and seventy two children and adolescents with the SVCS are reviewed and three patients are added.

Adolescent↗
PubMed1981

Alcohol consumption in a healthy population. Relationship to gamma-glutamyl transferase activity and mean corpuscular volume.

We analyzed the multivariate relationship between alcohol consumption and gamma-glutamyl-transferase (GGT), mean corpuscular volume (MCV), and tobacco consumption. A group of 995 healthy outpatients (604 men and 391 women, 18 to 76 years old) were systematically examined. Daily alcohol consumption was established after an interview regarding complete dietary habits. Significant correlations have been found between daily alcohol intake and corresponding GGT and MCV values, .35 and .34, respectively, in men and .24 and .21 in women. Multiple regression analyses confirm the superiority of GGt over MCV as a laboratory marker of alcohol intake and show the advantage of using them together. A rough estimation of alcohol consumption is proposed as a first step in mass screening of heavy drinkers.

Adolescent↗
PubMed1981

The structure of acid-soluble basement membrane collagen from bovine anterior lens capsule: molecular parameters and thermal gelation properties.

Basement membrane collagen was extracted from bovine anterior lens capsules with acetic acid in the presence of protease and proteinase inhibitors. This undegraded soluble basement membrane has a sedimentation coefficient S0 20,w=7.8 X 10-13 sec-1, a diffusion coefficient D020,w=5.82 X 10-8/ cm2/sec and a zero-shear intrinsic viscosity [eta] = 2200 cm3/g. These data lead to a molecular weight, Mr of 1.1 X 10(6). Electron microscopic observation indicates that the molecules are rod-like in character with a length of 300 nm. Theoretical models describing the intrinsic viscosity in terms of the distribution of mass in such an elongated molecule show that a dumbbell-like structure is the only tenable model. In this model a single 300 nm rod-like region joins two more densely packed globular regions. The globular domains contain hydroxyproline and may has collagenase sensitive regions since digestion with purified bacterial collagenase at 37 degree C for 18 h degrades these domains as well as the central triple-helical domain. The intact acid-soluble basement membrane collagen precipitates from neutral pH solutions upon warming 4 degree C stable solutions. The pH, ionic strength and concentration dependence parameters of this thermal precipitation have been examined. The basement membrane collagen precipitation appears to be dominated by end-region domain hydrophobic interactions. The end-regions are required for precipitation in contrast to the Type I procollagen situation wherein the intact end-regions inhibit thermal gelation. Electron microscopic examination of the basement membrane thermal gels shows networks of very thin filaments which may be related directly to the structure within intact basement membrane.

Amino Acids↗
PubMed1981

Study of a group of 484 fertile men. Part I: distribution of semen characteristics.

The semen characteristics studied were the sperm count, semen volume, morphology and pre-freeze and post-thaw motility. Two categories of fertile men were investigated: semen donor candidates for artificial insemination and pre-vasectomy subjects. Since mean values for each variable in the two series were similar, they could be considered as a single group of 484 fertile men. Only those subjects whose ejaculates were obtained after an abstinence of 5 days or less were retained. The distribution, mean and percentiles were determined for each variable. The 10th and 90th percentiles for sperm count, percentage of motile forms and percentage of normal cells were respectively 25 and 180 million per ml, 60% and 80% and 50% ad 75%. The three variables, sperm count, semen volume and total number of spermatozoa which were dependent on abstinence were analysed in the same manner for 3 days of abstinence. The group studied seemed to be as representative and as well defined as possible.

Adult↗
PubMed1981

Study of a group of 484 fertile men. Part II: relation between age (20-59) and semen characteristics.

Commonly measured semen variables as well as post-thaw motility have been studied as a function of age in fertile men. The mean age was 34.6 (SD = 6.6). No significant change with age was found for the sperm count, semen volume or total number of spermatozoa. Conversely, there were significant differences between age groups for the percentage of normal cells (P less than 0.01) and the percentage of motile forms (P less than 0.01) as well as for the after-thaw motility (P less than 0.001). These three variables rise, reach a maximum level at 30 to 35 years of age and then decrease. These changes are not explained by variations in the length of abstinence.

Adult↗
PubMed1981

Adh locus in maize for detection of mutagens in the environment.

The advantages of the maize Adh system for low level mutagenesis studies are discussed. They include high mutation rate and the availability of both a strong selection system for null mutants and a sensitive method for detection of variants. The null selection involves treatment of pollen with allyl alcohol which is converted by the Adh enzyme to the toxic acrylaldehyde. Adh variants can be detected by alteration in affinity for phytic acid as well as thermal stability and electrophoretic mobility.

Alcohol Oxidoreductases↗