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Biomedical subjects

J Tyson

Publications and source records attributed to J Tyson.

47 records · Page 3Linked to original sources
PubMed1979

Diurnal variation in the quality and outcome of newborn intensive care.

Variables related to both the process and the outcome of neonatal intensive care were studied to compare care given during the day (0901-2100 hours) with that at night (2101-0900 hours). At night, intravenous infiltrations occurred more often, and the tidal volume of respirator-treated infants was verified less often. Blood pH values less than 7.20, excluding values within 12 hours of admission, were recorded more often and in more patients at night. During a 12-month period, there were significantly more deaths among infants less than 1,500 gm during the night than during the day. The deterioration of infants at night may result in part from current nursery staffing practices.

Birth Weight↗
PubMed1978

Morphologic analysis of the pulmonary vascular bed in infants exposed in utero to prostaglandin synthetase inhibitors.

Since the effects of prostaglandin synthetase inhibitors on the developing human fetal pulmonary vasculature are unknown, we studied the lungs of two infants, one whose mother took salicylates and the other whose mother took indomethacin during pregnancy. Lungs were fixed by perfusion and fifth generation (resistance) vessels identified. The infant with chronic exposure to aspirin had premature constriction of the ductus arteriosus, tricuspid insufficiency, increased pulmonary arterial medial width/external diameter ratio due to increased smooth muscle, and a decreased number of pulmonary vessels/cm2 lung tissue. The infant with short-term exposure to indomethacin had hypoxemia, increased pulmonary arterial m/d ratio due to increased smooth muscle, and a normal number of pulmonary vessels/cm2 lung tissue. These abnormalities may be due to the effects of prostaglandin synthetase inhibitor drugs on the ductus arteriosus and/or the pulmonary vessels of the human fetus.

Adult↗
PubMed1976

Evolution of a women's clinic: an alternate system of medical care.

Following the Vermont Supreme Court decision, in 1972, invalidating an old statute against abortion, the community watched for change in hospital and medical practice. When none occurred, representatives of health agencies were jointed by feminists and others dissatisfied with existing medical facilities to form the Vermont Women's Health Center. Tensions resulting from differing viewpoints were channeled into the common goal of providing optimal health care involving paramedical personnel as well as gynecologists and other physicians. In 1973, 1,255 abortions were performed. Complications were monitored by the clinic, by the state health department, and by the International Fertility Research Program and were found to compare favorably with rates in larger clinics. Abortion-related visits initially outnumbered others by 2:1 but rapidly fell, indicating acceptance of the clinic for a variety of gynecologic services. After three years, the clinic is solvent, stable, and utilized by a wide range of women, the result of cooperation between the establishment and its critics.

Abortion, Legal↗
PubMed1970

Observations on the maturation of thyroid function in early fetal life.

Serum samples were obtained from 21 normal human fetuses after therapeutic abortion for psychiatric indications. Fetal crown-rump length ranged from 5.2 to 22.5 cm, corresponding to the gestational age of 65-168 days.Serum thyroxine, assayed by a modification of the Murphy-Pattee method, was identified in the second smallest fetus examined at 78 days gestation. Thereafter it increased rapidly, maintaining a significant linear correlation with crown-rump length until term (r = 0.800, P < 0.001). Free thyroxine (FT4) also increased in a linear relation to gestational age (r = 0.908, P < 0.001), but reached term levels by 18-20 wk. Radioimmunoassayable thyroid-stimulating hormone (TSH) was detected at 78 days gestation. Levels increased rapidly with advancing gestation, so that by 16 wk almost all were within the range of term infants. After 16 wk gestation, levels were usually greater than 4.0 muU/cc, higher than that seen in normal children. No correlation was demonstrated between the serum TSH levels and total thyroxine. TSH and FT4, however, increased in a parallel manner with a significant positive correlation. This suggested that fetal TSH secretion was responsive to FT4 levels from very early in gestation, possibly as early as 11 wk.Thyroxine-binding globulin (TBG) was detected in a fetus of 78 days gestation (1.4 mug/100 ml). Levels increased rapidly, paralleling the rise in serum thyroxine and maintaining a linear correlation with crownrump length (r = 0.864, P < 0.001). Thyroxine-binding prealbumin binding capacity (TBPA) in fetuses 14-24 wk gestation was comparable with that seen at term. When examining the distribution of tracer amounts of thyroxine-(131)I (T4-(131)I) between the thyroxine-binding proteins, it was found that a major fraction was bound to TBPA and albumin during the early part of gestation. This decreased linearly with maturation of the fetus as the fraction bound to TBG increased. By 20 wk gestation fetal TBG was able to bind 78% of tracer despite a TBG capacity of only 7.7 mug/100 ml. This appeared to be the result of relatively low concentrations of TBPA and albumin during this period of gestation. The theoretical association constant calculated for fetal and newborn TBG was found to be similar to that estimated for normal adult males and females.

Body Height↗