Atrial natriuretic peptide in the sheep.

To study atrial natriuretic peptide (ANP) physiology in the chronically catheterized pregnant sheep model we developed a heterologous radioimmunoassay for ovine ANP using an antiserum raised against 1-28 human ANP. This antiserum (Tor I) is specific for the aminoterminus of the human ANP molecule and shows little cross reaction with any carboxyterminus ANP fragments. Ovine ANP immunoreactivity was characterized using this antiserum and a commercially available carboxyterminus ANP antiserum obtained from Peninsula Laboratories.

Ontogeny of thyroid hormone effect on tissue 5'-monodeiodinase activity in fetal sheep.

Most of the thyroxine (T4) in fetal mammals is deiodinated to the inactive metabolite, reverse triiodothyronine (rT3), via an iodothyronine 5-monodeiodinase in fetal tissues. Maturation of the tissue 5'-monodeiodinase (MDI) enzymes required for conversion of T4 to active triiodothyronine (T3) in the rat, an altricial species, occurs in the postnatal period. To characterize fetal maturation of the enzymes for active T3 production in a precocial species, 5'-MDI activities were measured in liver, kidney, and brain tissue homogenates of ovine fetuses 13 days after total thyroidectomy (Tx) conducted at gestational ages of 99-107 or 129-132 days.

Ovine fetal urine contribution to amniotic and allantoic compartments.

The ovine pregnancy has been extensively studied as a model for amniotic fluid metabolism potentially serving as a model for human oligohydramnios. However, it is recognized that the ovine pregnancy contains an allantoic fluid compartment not present in human pregnancies at term. Earlier studies in sheep suggested that the fetal urine contribution to allantoic fluid diminished at term, but without an explanation for maintenance of the significant volume of the allantoic cavity.

Arginine vasotocin and a novel oxytocin-vasotocin-like material in plasma of human newborns.

Plasma of human adults contains an oxytocin, vasotocin-like (OT-VT) immunoreactive material that is estrogen responsive in both males and females and the levels of which are elevated during pregnancy. Although OT-VT is immunoreactive with an antiserum raised against synthetic arginine vasotocin (AVT), the elution profile of OT-VT by high-performance liquid chromatography (HPLC) is distinct from AVT, arginine vasopressin (AVP) or oxytocin (OT). Because the fetus is also exposed to high estrogen levels during pregnancy and AVT has been reported to be present in human fetal pituitaries, cord blood samples from 16 vaginally delivered human newborn infants were examined for evidence of OT-VT and AVT.

Stress fractures of the medial malleolus.

Six athletes, all engaged in running activities at the time of injury, presented with tenderness over the medial malleolus and ankle effusion. Three patients had a fracture line which could be seen on radiographs. These patients were treated by open reduction and internal fixation using two 4.

The source of urinary epidermal growth factor in humans.

To clarify the source of human urine EGF, we studied EGF renal clearance in 20 healthy, young adult subjects. Immunoreactive EGF was measured hourly in EDTA plasma, heparin plasma, serum and urine of 12 males and 8 females during a 3 h study period. Plasma and urine creatinine and creatinine clearance were measured and calculated hourly.

Ovine fetal and adult atrial natriuretic factor metabolism.

Studies were conducted to quantify ovine fetal and adult atrial natriuretic factor (ANF) metabolism. A total of 14 pregnant ewes with singleton fetuses were prepared with vascular catheters. In protocol 1, six fetuses (mean gestation, 131 +/- 1 days) received intravenous infusions of synthetic human ANF (hANF, 100 ng.

Epidermal growth factor in the developing mammal.

EGF has been characterized as an important growth factor in mammalian development and function, but its precise roles and significance are not yet clear. EGF may have a role in embryogenesis and fetal growth, since receptors have been identified in fetal tissues. However, EGF mRNA has not been shown in the fetus, and it seems likely that the related peptide, alpha TGF, subserves a developmental role in the fetus.

Idiopathic scoliosis: transcutaneous muscle stimulation versus the Milwaukee brace.

This paper compared 3-year results of electrical stimulation with the Milwaukee brace for the treatment of idiopathic scoliosis. Fifty patients in each group were compared retrospectively and matched for age, sex, Risser sign, and curve morphology. Evaluations were performed at 6-month intervals with radiographs and examinations.

Elbow joint: normal anatomy on MR images.

The normal anatomy of the elbow joint in axial, sagittal, and coronal planes was evaluated by comparing 30 magnetic resonance (MR) images of eight healthy volunteers with microtomed cryosections prepared from six cadaver elbows. MR images provided depiction of muscles and tendons, bone marrow, articular cartilage, and neurovascular structures. Cross-referencing of MR images from one plane to another was useful in the evaluation of complicated, obliquely oriented muscle bundles and other soft tissues.

Plasma atrial natriuretic peptide response to volume expansion in the ovine fetus.

Atrial natriuretic peptide is a potent diuretic and vasorelaxant peptide secreted from the cardiac atria of adult mammals in response to increased intravascular volume. In sheep, fetal plasma levels of atrial natriuretic peptide are significantly greater than maternal levels, but the factors that control fetal release of atrial natriuretic peptide have not been defined. The present studies were conducted to determine whether the fetus responds to increased intravascular volume by atrial natriuretic peptide secretion.

Autoimmune thyroid disease: an expanding spectrum.

Autoimmune thyroid disease classically has included Hashimoto's thyroiditis and Graves' disease. Hashimoto's thyroiditis probably also includes focal thyroiditis, fibrous thyroiditis, primary myxedema, and Hashitoxicosis as variants. Graves' disease is associated with ophthalmopathy and dermopathy, and recent evidence suggests that these manifestations are autoimmune phenomena as well.

Effectiveness of newborn screening programs for congenital hypothyroidism: prevalence of missed cases.

The author reviews the background information and technical developments leading to newborn screening for congenital hypothyroidism as well as the effectiveness and problems of the programs during the past decade. The success of the programs in terms of prevention of mental retardation now is clear. It is also clear, however, that a significant number of affected infants, perhaps 8 to 10 per cent of the total, can be missed in the best of screening programs.

Effect of fetal thyroidectomy on newborn thermogenesis in lambs.

We investigated the effect of the transient neonatal hyperthyroid state on thermogenesis at birth by measuring rectal temperature, plasma free fatty acids, plasma catecholamines, and in vitro brown adipose tissue respiration in thyroidectomized (n = 6) and sham operated (n = 5) fetal sheep. Surgery was performed at an average of 133 days of gestation followed by cesarean delivery at 146 days. Fetuses were delivered into a constant room temperature of 25 degrees C.

Epidermal growth factor acts as a corticotropin-releasing factor in chronically catheterized fetal lambs.

Epidermal growth factor (EGF) has been reported to stimulate adrenocorticotropin hormone (ACTH), growth hormone and prolactin secretion from pituitary tissue in vitro, and in large doses evokes ACTH secretion in adult sheep in vivo. In order to assess a possible role for EGF in the pituitary hyperfunction characteristic of the in utero fetus, we measured changes in plasma immunoreactive ACTH concentrations after acute administration of saline, purified mouse EGF or synthetic ovine corticotropin releasing factor (CRF) to chronically catheterized fetal sheep. Both CRF and EGF were associated with increases in plasma immunoreactive ACTH concentrations.

Cold-induced increase in brown fat thyroxine 5'-monodeiodinase is attenuated in Zucker obese rat.

In this study we examined the possibility that the reduced brown adipose tissue (BAT) thermogenesis in the Zucker obese rat may result from a limited capacity for enzymic conversion of thyroxine (T4) to triiodothyronine (T3) in BAT. A total of 34 lean and obese rats, approximately 4 mo old were divided into three treatment groups: group 1 (5 lean and 6 obese) was fed Purina rat chow for 21 days, and group 2 (5 lean and 6 obese) was fed a cafeteria diet for 21 days, and group 3 (6 lean and 6 obese) was fed Purina rat chow and maintained in the cold (8 +/- 1 degrees C) for 7 days. The lean and obese rats in all three groups of animals were matched closely for age and respective body weight.

Treatment of neonatal hyperthyroidism due to Graves' disease with sodium ipodate.

We describe the effect of administration of repeated doses of sodium ipodate in a newborn infant with hyperthyroidism due to transient Graves' disease. Pretreatment (day 3) serum T4 and T3 concentrations were 49 micrograms/dl and 590 ng/dl, respectively. With 24 h after the first dose of ipodate, serum T3 fell by 40%, and it subsequently ranged from 209-278 ng/dl throughout the 39-day ipodate treatment period.

Fetal arginine vasopressin under basal and hypoosmolal conditions.

Blood samples (4 ml) for plasma arginine vasopressin (AVP) measurements were obtained at 3- to 4-hour intervals under basal conditions for 1-2 days from 5 date-bred ewes with chronic maternal and fetal vascular catheters. In addition, 6 chronically catheterized ewes were infused with 2 liters of 0.45% NaCl over 30 min.

Nerve growth factor immunoreactivity in mouse kidney: an immunoelectron microscopic study.

We have recently reported the immunolocalization of nerve growth factor (NGF) in mouse kidney by light microscopy. In the present study, we have investigated the ultrastructural localization of NGF by the preembedding immunoperoxidase method for electron microscopy. NGF immunoreactivity was present in the connecting tubule cells of the distal nephron.

Renal effects of ovine fetal arginine vasopressin secretion in response to maternal hyperosmolality.

Acute increases in maternal plasma osmolality can increase amniotic fluid osmolality. Amniotic fluid is primarily derived from fetal urine production, and arginine vasopressin infusion can affect both fetal urine production and amniotic fluid osmolality. To assess the effect of short-term changes in maternal osmolality on fetal arginine vasopressin secretion and renal function, six ewes of 126 +/- 1 days' gestation received intravenous infusions of 20% mannitol (500 ml/10 min).

Effect of thyroid hormone and sex status on epidermal growth factor concentrations in the submandibular gland of a congenitally hypothyroid mouse model.

Studies were performed to explore the role of thyroid hormone and sex status on epidermal growth factor concentrations in the submandibular gland of a congenitally hypothyroid mouse model designated hyt/hyt. The animals were studied at 20, 30 and 40 days of postnatal age. The euthyroid animals were homozygous or heterozygous for the hypothyroid gene.