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Biomedical subjects

P Goldstein

Publications and source records attributed to P Goldstein.

15 recordsLinked to original sources
PubMed1992

Effects of dimethyl sulfone (DMSO2) on early gametogenesis in Caenorhabditis elegans: ultrastructural aberrations and loss of synaptonemal complexes from pachytene nuclei.

The free-living nematode Caenorhabditis elegans has been used extensively for studies in developmental and reproductive genetics. Recently, toxicologic studies have been initiated using specific sex chromosome mutations. In the present study, high incidence of male (him) mutants, him-5 and him-8, were treated with dimethyl sulfone (DMSO2), the primary metabolite of dimethyl sulfoxide (DMSO). In addition to differential effects on X-chromosome nondisjunction, loss of viability and fertility were observed. Much lower concentrations of DMSO2 were required to elicit the same aberrational effects characteristic of DMSO (1); thus, the toxicity of the former was significantly more potent. The observed decrease in life span was associated with senescent morphology of meiotic prophase nuclei, such that nuclei from young and old specimens could not be differentiated. Aging in oocytes at pachytene is characterized by nucleo-cytoplasmic aberrations, increased density of the nucleoplasm and cytoplasm, and decrease in numbers of mitochondria. Increasing concentrations of DMSO2 resulted in a corresponding decrease in fertility and increased production of abnormal gametes. At DMSO2 concentrations higher than 1.0%, synaptonemal complexes (SC) were absent from pachytene nuclei; thus, effective pairing and segregation of homologous chromosomes was prohibited. Since the SC is essential for regulating pairing and subsequent separation of bivalents, the lack of an SC explains the loss of fertility, due to the production of unbalanced gametes, observed in DMSO2-treated specimens.

Animals↗
PubMed1992

[Hydatid cyst of the kidney in the child].

Three pediatric cases of hydatic cyst of the kidney are reported. This is a very rare condition in children. Usually, the presentation is a cystic space-occupying lesion of the kidney. Several diagnostic methods are available but it is stressed that ultrasonography may be sufficient. Surgical treatment is still necessary.

Child↗
PubMed1979

A prospective evaluation of placental lactogen as a test for neonatal risk.

This study evaluates the usefulness of maternal serum concentrations of human placental lactogen in the management of high-risk pregnancies. The study was performed in a community hospital over a year's time and involved 250 gestations. The test detected only 11.4% of the pregnancies defined as high-risk by clinical criteria and none of the pregnancies in which the newborn was compromised. Serum human placental lactogen is an insensitive test in predicting the outcome of pregnancies in an obstetric population unless historical information regarding maternal disease is unavailable.

Female↗
PubMed1979

Karyotype analysis of the plant-parasitic nematode Heterodera glycines by electron microscopy. 1. The diploid.

Heterodera glycines is a diploid amphimictic nematode with n = 9 chromosomes. Nine normal synaptonemal complexes (SC) were detected following 3-dimensional reconstruction of pachytene nuclei from electron microscopy of serial sections. Regions of unique 'modified synaptonemal complexes' (MSC) were observed along 2 SCs. These consist of a heterochromatic knob within which the SC appears either disorganized or stacked in layers of lateral elements. Its function is not known. Recombination nodules and 'cylindrical granular complexes', were not observed in H. glycines.

Animals↗
PubMed1978

Anaerobic metabolism and wound healing: an hypothesis for the initiation and cessation of collagen synthesis in wounds.

The implanted cylinder model was used to measure LDH activity and lactate and pyruvate concentrations in the extracellular fluid of wounds and wound tissue. Total LDH activity corresponded directly to lactic acid concentration and inversely to oxygen availability. LDH isoenzymes in wound fluid were in an anaerobic pattern soon after injury and evolved toward the aerotic pattern as oxygen supply more nearly matched metabolic capacity. Lactate levels in the wound space are elevated soon after wounding and remain elevated far above those in blood. These data again indicate that wound metabolism is characterized by a relatively poor oxygen supply. Current data from several sources indicate that lactate found in the hypoxic area of the wound may stimulate collagen synthesis in fibroblasts lying in the high lactate environment. We postulate that elevated concentration of lactate in wounds is a major signal for collagen synthesis and repair.

Anaerobiosis↗
PubMed1978

Use of doxycycline in elective first trimester abortion.

Elective first trimester abortion was performed in 263 patients, including 86 control patients and 177 patients receiving doxycycline as prophylactic antibiotic coverage. Abortions were done by the same physicians, using a standard protocol. Control and study populations had similar courses, except that the incidence of major complications and total complications was significantly reduced in the group receiving doxycycline. No untoward reactions to the drug were noted, and patient compliance was excellent. The results suggest that the low morbidity of elective suction abortion is further reduced by prophylactic doxycycline.

Abortion, Induced↗
PubMed1977

Chromatin diminution in early embryogenesis of Ascaris lumbricoides L. var. suum.

The occurrence of chromatin diminution in early Ascaris lumbricoides L. embryos has been studied in detail, and it is shown that it is possible to preselect three characteristic types of mitoses: pre-diminution, diminution, and post-diminution mitosis. The first three embryonic mitotic divisions are of the pre-diminution type. Chromatin diminution occurs after the third mitosis, but there is a variation from embryo to embryo as to whether or not chromosomal diminution occurs during the fourth, fifth, and six divisions. However, the seventh embryonic division, which gives rise to an eight-cell embryo, always exhibits chromatin diminution. Subsequent mitoses of somatic cells already in the diminished state are of the post-diminution type of mitosis.

Age Factors↗
PubMed1977

Spermatogenesis and spermiogenesis in Ascaris lumbricoides Var. suum.

Reorganization of the prophase I nucleus marks the beginning of the first meiotic division. A pair of centrioles is present at each pole at metaphase I and mitochondria are not observed in the spindle area. A chromosomal pellicle, which resembles a kinetochore plate but has no apparent association with microtubules, surrounds each autosome at metaphase I and II. The sex body lags behind the autosomes at anaphase I and segregates differentially to one daughter cell. Mitochondria and a pair of centrioles are present in the spindle during the second meiotic division. Localized condensation of chromatin and fusion of the condensed chromatin of the secondary spermatocyte telophase nucleus results in a compact spermatid nucleus. Loss of spermatid cytoplasm is effected by the ejection of a cytophore vesicle.

Animals↗
PubMed1976

Karyotype analysis of Ascaris lumbricoides var. suum. Male and female pachytene nuclei by 3-D reconstruction from electron microscopy of serial sections.

Twelve synaptonemal complexes are present in both oocyte and spermatocyte pachytene nuclei of Ascaris lumbricoides var. suum, as determined by 3-D reconstruction of the nuclear contents from electron microscropy of serial sections and therefore, n=12 in the strain of Ascaris described here. In the female the heterochromatic end of each synaptonemal complex is attached to the nuclear envelope and the other end is free in the nucleoplasm. In the male neither end of the synaptonemal complex is attached, but there is a heterochromatic knob at one end of each complex. Five additional large heterochromatic masses are present in the spermatocyte nucleus and these may be the sex chromosomes described by earlier workers.

Animals↗
PubMed1976

Fetal biparietal diameter as a predictor of a mature lecithin/sphingomyelin ratio.

The records of 148 patients who had undergone simultaneous determination of fetal biparietal diameter and lecithin sphingomyelin ratio were reviewed. The results of the lecithin sphingomyelin determination could not be predicted with an acceptable degree of accuracy utilizing the fetal biparietal diameter. When patients were grouped by maternal disease, no significant difference between diabetic and control patients was noted. Other subgroups were too small to allow a valid statistical comparison.

Amniotic Fluid↗
PubMedDate not supplied

Transfusion lung.

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Adolescent↗