John E. Tyson

Prolactin-Secreting Tumors and Hypogonadism in 22 Men

We studied 22 men with prolactin-secreting pituitary tumors and hypogonadism. Twenty complained of impotence, nine had visual impairment, and three experienced galactorrhea. None of the 17 patients undergoing operation or radiotherapy, or both, were subsequently normoprolactinemic. In all 13 patients treated with bromocryptine major clinical improvement was associated with a decrease in serum prolactin levels and in nine with an increase in serum testosterone. Two patients receiving testosterone replacement therapy showed improved potency only after bromocryptine was administered. The results indicate that hyperprolactinemia frequently induces hypogonadism in men, that bromocryptine ameliorates symptoms of disease previously unchanged by operation or radiotherapy, and that the impotence observed may not be solely the result of hypogonadism.

Increases in magnetic hyperfine field at the surface of ultra‐thin epitaxial Fe films (invited)

Previous investigations of ultra‐thin epitaxial Fe (110) films grown on Ag (111) have indicated that there is a measurable increase at 4.2 K in the magnetic hyperfine field compared with bulk value in iron atoms in the first three surface layers of the films. As these films were produced in ultra‐vacuum and then removed for study by transmission Mossbauer spectroscopy it was necessary to provide a protective overcoat to prevent oxidation of the surface. Because of this it was not possible to rule out interaction of the Fe surface with the overcoat layers as a cause of the increased surface hyperfine field. A series of new films have been made of isotopically pure 56Fe. A thin probe layer of 57Fe ranging in thickness from 4–10 A was then deposited on the film surface and a variety of different overcoat layers subsequently chosen to protect these films. Overcoating materials included Ag, Au, Cu, Ge, MnF2, and NaCl. While there were differences in the hyperfine fields and isomer shifts of the 57Fe probe laye...

Impact of maternal euglycemia on fetal outcome in diabetic pregnancy

Abstract We examined the relationship between maternal euglycemia and fetal outcome in 81 cases of gestational, diet-controlled (GD) diabetes and 32 cases of insulin-dependent diabetes (IDD). The perinatal mortality rate was reduced from 2.3% to zero in an 18 month period ending in December 1977. Perinatal morbidity in GD and IDD was comparable and independent of age, parity, and severity of diabetes. Fasting maternal glucose concentrations correlated positively with the incidence of fetal macrosomia (p = all diabetic patients. On the other hand, neonatal morbidity can be expected to be higher in women with gestational diabetes identified late in pregnancy. Likewise, congenital malformations in this group may represent the influence of uncontrolled glucose metabolism in the early months of gestation which remained undetected due to late registration for prenatal care.

Neuroendocrine dysfunction in galactorrhea-amenorrhea after oral contraceptive use.

Nonpuerperal alactorrhea and amenorrhea have been reported following the use of oral contraceptives. Treatment of this condition with ergot alkaloids has proved to be of great therapeutic value. Pretreatment plasma hLH and hFSH concentrations in 13 women with postqill galactorrhea-amenorrhea (PPGA) were 6.6 plus or minus 0.6 (SE.) and 5.0 plus or minus 0.8 mlU/ml, respectively. The mean prolactin concentration was 80.7 plus or minus 13.2 ng/ml. After complete evaluation in which diagnostic evidence of pituitary tumor was absent, the patients were treated with ergocryptine (CB-154). The mean hPRL concentration at 14 days of therapy was 7.8 p;us or minus 1.9 ng/ml. Cyclic gonadotropin secretion resumed in all but one instance; ovulation was confirmed on the basis of a biphasic temperature chart and in 5 cases, endometrial biopsy. Measurement of serum dopamine-beta-hydroxylase (DBH) activity indicated a significant decline at the end of 8 weeks of CB-154 therapy. The fall in hPRL was not necessarily associated with a fall in DBH. The majority of women in this study exhibited a consistent personality suggesting varying degrees of anxiety unrelated to the PPGA and usually antedating the use of oral contraceptives. PPGA was found in women without hyperprolactinemia, but altered hPRL secretion was evident in all instances. The data suggest that the disorder of cyclic gonadotropin secretion is related to altered hPRL secretion, but the mechanism is possibly related to a catecholamine abnormality. The data support the presence of an inherent cyclic mechanism for the secretion of gonadotropins. CB-154 therapy does not affect conception, and no teratogenic effects were observed in 2 infants born to women who had received CB-154 during the first 40 days of gestation.

Inhibition of fetal membrane prostaglandin production by prolactin: Relative importance in the initiation of labor

Production of a biologically active prolactin by human decidual tissue and its influence on the permeability of amniochorion to water suggests a functional relationship between the polypeptide and fetal membrane metabolism. Under in vitro circumstances, we used ovine prolactin and the Ussing chamber technique to determine the role of prolactin in prostaglandin E2 production by human fetal membrane. Fresh reflected membranes obtained from elective cesarean sections were exposed to ovine prolactin (10 micrograms/ml). Aliquots of incubation media were sampled at 0, 30, 60, 120, and 240 minutes, quick-frozen, and later assayed for prostaglandin E2. Multifactorial analysis of variance revealed that ovine prolactin significantly reduced prostaglandin E2 production (f = 13.42, p less than 0.005). Prostaglandin E2 output was greatest by amnion (3581 +/- 596 pg/ml/gm declining to 1819 +/- 452 pg/ml/gm during 4 hours). Other combinations of fetal membranes including amnion-chorion-decidua produced only 12% to 15% prostaglandin E2 per gram compared with that produced by amnion alone. Those membranes similarly responded to prolactin with a reduction in prostaglandin E2 output of 34% to 59%. Correlation analysis identified a significant relationship between prostaglandin E2 production and time (r = 0.298; p less than 0.001), which was abolished by ovine prolactin (r = 0.115, p greater than 0.10). This model illustrates that ovine prolactin modifies the production of prostaglandin by fetal membranes in vitro. By analogy, endogenous prolactin by human decidual tissue might also inhibit the elaboration of prostaglandin E2 from its precursors residing within the fetal membranes.

Experimental temperature dependence of the magnetization of surface layers of Fe at interfaces with nonmagnetic materials

Theoretical studies have investigated the temperature dependence of the magnetization at the surface of ferromagnets. For isotropic exchange uniform throughout the sample, the temperature dependence of the surface magnetization varies asM(T)/M(0)≈(1−BT3/2) with aB factor at least twice as great as the bulk value. For cases in which the exchange interaction is different in the surface layer, or in which there is a significant surface exchange anisotropy, a different temperature dependence may result. These theoretical results have seen little experimental test. We report here measurements made on epitaxial (110) Fe films in which different temperature dependences are found depending upon the interfacial material chosen as a covering layer.

Mössbauer spectroscopic studies on surfaces and thin films

Abstract We have investigated the magnetic properties of surface layers of Fe films using Mossbauer spectroscopy. (110) epitaxial Fe films were made of 56 Fe with appropriate probe layers of 57 Fe in the surface region. In this way we were able to profile the magnetism at and near the surface of our films. Studies of the temperature dependence of layers at the surface indicate a quasilinear dependence of magnetization on temperature while the temperature dependence of layers further inside the material show the usual T 3/2 dependence. In addition to this we note that a region of surface thermal spin deviations larger than bulk values extends over 3 to 4 layers at the surfaces. These results are in qualitative agreement with a number of theoretical studies including those of Mathon. Bender and Hohenberg, and Wolfram et al. The quasilinear temperature dependence of the surface layer implies a weakening of the surface exchange. In addition to the unusual temperature dependence of the surface magnetization we have generally observed larger surface magnetic hyperfine fields near T = 0.

The Maintenance of Infecundity in Postpartum Women

The duration of postpartum infertility in nursing women relies heavily upon the effectiveness of the nursing stimulus (1), which in turn provokes the secretion of the pituitary hormone prolactin (PRL), This secretion is induced by a neural reflex arc and a change in hypothalamic dopamine turnover (2–4). While the influence of this change is poorly understood, there is evidence to suggest that the peripheral plasma concentration of PRL modulates both hypothalamic and ovarian function (5), including the attenuation of cyclic luteinizing hormone releasing hormone secretion via a positive short loop feedback (6) and a tonic inhibition of ovarian steroidogenesis (7). Furthermore, PRL may block FSH activity at the ovary (8, 9). The priority of these several mechanisms remains elusive. The duration of postpartum infertility apparently varies both with the type of nursing and the PRL response to such nursing (10). Thus, lactation has been considered a poor method of contraception. The following studies extend our observations on the hormonal mechanisms relating nursing to postpartum infertility.

Diagnosis and treatment of abnormal lactation

The literature on conditions associated with abnormal lactation is reviewed. Abnormal pituitary prolactin secretion (hPRL) is not always related to lactation. This makes it difficult to classify galactorrhea-amenorrhea on the basis of pituitary dysfunction of hPRL secretion. Pharmacologic doses of estrogen can enhance hPRL secretion and promote breast enlargement when administered with intermittent thyrotrophin-releasing hormone (TRH). Withdrawal of medication results in milk production and letdown. hPRL is thought to have a free role in the uptake of estrogens by the mammary cells. A single injection of 150 mg of medroxyprogesterone acetate every 3 months increases lactation and duration of breast-feeding. The discontinuation of oral contraceptive use may result in galactorrhea-amenorrhea in some women. Nonsteroidal drugs such as reserpine tricyclic antidepressants methyldopa and opiates can cause abnormal lactation. Abnormal lactation may also accompany treatment for precocious puberty the McCune-Albright syndrome and the juvenile postabortion period. Chromophobe adenoma acromegaly Forbes-Albright syndrome occult pituitary neoplasia and pseudoneoplasia and hypothyroidism are associated with abnormal lactation. Some of the newer tests for the study of pituitary function in cases of abnormal lactation include the TRH stimulation test the phenothiazine stimulation test and the L-dopa test. The L-arginine infusion test and the insulin tolerance test are useful for the dissociation of growth hormone- and hPRL-secreting tumors. The successful removal of pituitary adenomas has been reported to restore cyclic gonadotropin secretion and cause galactorrhea to disappear. L-dopa and ergocryptine (CB-154) therapy have been successful in treating postpill amenorrhea-galactorrhea though L-dopa treatment has numerous undesirable side effects. It is suggested that prolactin secretion directly influences the secretion of cyclic gonadotropins and that the suppression of cyclic gonadotropin secretion and hyperprolactinemia are mainly indications of a disorder of catecholamine asecretion. Drugs that inhibit hPRL secretion should not be used to treat galactorrhea-amenorrhea without a thorough and exhaustive evaluation of prolactin secretion estrogen production and cyclic gonadotropin secretion.

Fetal tachycardia associated with intrauterine fetal thyrotoxicosis.

&NA; Tachycardia in both fetuses of a twin gestation was documented in a mother who had undergone subtotal thyroidectomy 8 years prior to her present pregnancy. Maternal and fetal plasma concentrations of long‐acting thyroid stimulator (LATS) and amniotic fluid 3,3′,5′‐triiodothyronine (reverse T3) were determined. All values were consistent with the diagnosis of fetal thyrotoxicosis, as were cord blood studies performed on the fetuses post partum. Significant concentrations of LATS were present in fetal cord blood. The first fetus survived but suffered hyperthyroidism during the first 3 neonatal weeks. The second twin died, possibly of fetal thyrotoxicosis. These studies suggest that in women with a history of thyrotoxicosis, high levels of maternal LATS may in some instances provoke fetal thyrotoxicosis, which can be diagnosed by the measurement of amniotic fluid reverse T3.