The age curve of nervous system tumour incidence in adults: common shape but changing levels by sex, race and geographical location

A multiplicative model was fitted to incidence rates of nervous system tumours cross-tabulated for each sex by five-year age groups between ages 35-64 and 51 populations in which at least ten cases had been observed and 60% of cases histologically verified. There was no significant departure from a model in which the age curve was assumed to have the same shape but a different level in each population. On log-log scale this shape was a straight line with identical slope (2.6) for males and females. Population-specific multipliers were highest in Israel and lowest in Asia. Within the US, rates were significantly lower among blacks, Hispanics, Chinese and Japanese compared to whites. A model for both sexes combined showed that sex ratios were rarely below unity but varied significantly between populations. Exposure (or susceptibility) to as yet unidentified aetiological factors appears to be higher in males and whites than in females and non-whites.

Origins and regional distribution of blood flow to the respiratory muscles in conscious sheep

The blood flow to the portions of the diaphragm (sternal, costal, and crural) and to the external and internal intercostal muscles was measured, using radio-labelled microspheres, in 12 young sheep breathing quietly. We calculated total blood flow and oxygen uptake of the diaphragm (VO2di). We also determined the proportion of diaphragmatic and intercostal muscle blood flow that arose from the descending aorta. Diaphragmatic blood flow (Qdi) was 0.62 +/- 0.04% of cardiac output (mean +/- SEM). VO2di was 1.53 +/- 0.15 ml X min-1 X 100 g-1, and was linearly related to Qdi. When standardized for weight Qdi was 28.3 +/- 1.5 ml X min-1 X 100 g-1, significantly greater than both external intercostal muscle blood flow (18.9 +/- 2.6 ml X min-1 X 100 g-1; P less than 0.05), and internal intercostal muscle blood flow (11.4 +/- 1.4 ml X min-1 X 100 g-1; P less than 0.01). Blood flow to the costal portion of the diaphragm was significantly less than blood flow to the crural portions. There was no difference between flow to these portions and to the sternal portion of the diaphragm. The blood supplying the dorsal-most regions of the diaphragm arose predominantly from the descending aorta. The results suggest that the crural portions work at a higher rate than the costal portions under resting conditions.

Drugs and stillbirth

In a case-control study spanning five years' experience at Group Health Cooperative of Puget Sound, we could demonstrate no plausible association between the use of spermicides, oral contraceptives, Bendectin, or antibiotics prior to conception and the occurrence of 73 nontraumatic stillbirths.

Conjugated estrogens and fibrocystic breast disease

The association between replacement estrogen use and subsequent development of fibrocystic breast disease was studied at Group Health Cooperative of Puget Sound. Included were 142 women aged 50-64 years diagnosed by biopsy as having fibrocystic breast disease during the years 1978 through 1983. The relative incidence of hospitalization for estrogen users compared with non-users was 1.9 (95% confidence interval 1.3-2.7). The association became stronger with increasing duration of estrogen use.

Differential isoform distribution between stored and secreted prolactin

PRL exists within the mammotroph population in a number of different molecular forms. Three of these forms are best described as isoforms, as they have the same mol wt (24K) but differ in their net molecular charges. In this study we have examined the relative proportions of newly synthesized isoforms found in stored (intracellular) vs. secreted (extracellular) PRL. Dissociated cells from female rat anterior pituitaries were cultured for 48 h and then incubated in [35S]methionine (6 h; 37 C). Intracellular and medium proteins were then extracted and resolved by one- and two-dimensional polyacrylamide gel electrophoresis, followed by silver staining or autoradiography. Control experiments, in which biosynthetically labeled PRL was re-extracted, ensured that the isolation conditions did not in themselves promote isoform interconversion. The relative proportions of the PRL isoforms were determined by densitometric scanning of developed autoradiograms. In the cell extracts, the relative proportions were 13.6 +/- 2.1% isoform 1 (least negatively charged), 71.5 +/- 3.26% isoform 2, and 14.7 +/- 1.9% isoform 3 (most negatively charged). In the medium, the relative proportions were 60 +/- 2.89% isoform 1, 20 +/- 1.75% isoform 2, and 11 +/- 1.14% isoform 3. When the labeling was performed in the presence of 0.5 mM cysteamine (an agent we show to distinguish between newly synthesized and older stored hormone and, hence, between the previously described functional subpopulations of mammotrophs), the same ratios of newly synthesized isoforms were secreted from the cells. We conclude that secretion of the different isoforms is more complex than simple proportional release of each form, and based on the cysteamine results, this nonproportional release cannot be attributed to release of one isoform per functional subpopulation of mammotrophs.

Specific and reversible degranulation of pituitary mammotrophs

When dissociated anterior pituitary cells were cultured over a layer of gelatin, electron microscopic observation showed the mammotrophs in the culture to be essentially degranulated and to have massively dilated rough endoplasmic reticulum (RER) and Golgi apparatus (GA), while there were no discernible effects on any of the other cell types. PRL synthesis in the gelatin-cultured cells occurred at twice the rate of that in the control cells and the gelatin-cultured cells contained 3% of the normal amount of PRL. Transfer of the cells to a more traditional culture situation reversed most of the morphological changes within 24 h. The mammotrophs were responsive to thyrotropin-releasing hormone (10(-7) M) both immediately after gelatin culture (3-fold control) and after reversal (5-fold control). As placement of the gelatin-cultured cells into traditional culture synchronizes the onset of granulation, we conclude that mammotrophs cultured in this fashion will be useful in the further study of PRL synthesis, packaging, storage and degradation.

Phasic respiratory activity in the fetal lamb during late gestation and labour

We quantified the respiratory activity of 9 fetal lambs using computer-analysis of the diaphragmatic electromyogram (EMG) obtained during 2 h recording sessions interspersed over the last 13 days of gestation. The fetuses delivered unassisted at an average gestational age of 145 days (term = 147 days). During the last 2 h of labour the number of phasic EMG bursts (breaths) averaged 3% of the peak recorded earlier in the study. This decline in breathing began at least 2 days before labour and resulted predominantly from the fetus spending an increasing proportion of time in apnoea. Respiratory rate within epochs of breathing also fell significantly 1 day before labour, and the proportion of time spent in the low voltage electrocortical state declined once labour commenced. No significant change occurred in arterial PO2, PCO2 or pH over the study period. We conclude that fetal respiratory activity falls well before the onset of labour, largely as a result of increased apnoea, and that the decline does not result from the development of a progressive hypoxaemia associated with labour.

Increased dietary leucine changes the rhythm of prolactin secretion

As we have recently shown that prolactin secretion in vitro is regulated by extracellular leucine, we wanted to determine whether leucine had a similar regulatory action on prolactin secretion in the intact animal. Leucine was administered to cycling female rats by way of their drinking water (0.5%) for a period of 24 days. At daily intervals during this time, six control and six leucine-treated rats were killed and their trunk blood subsequently assayed for prolactin content. On days 7, 14, and 21 during this period, pituitaries from the sacrificed rats were fixed and processed for electron microscopy. Leucine treatment resulted in an alteration in the normal four-day cyclicity in serum prolactin levels and a stimulation of prolactin synthesis as evidenced by ultrastructural changes in the pituitary mammotrophs. In a parallel set of experiments, daily vaginal smears were taken from nonsynchronized animals for 24 days before and 24 days during leucine administration. Leucine treatment resulted in variable alterations in the estrus cycle depending upon the stage of the cycle when the leucine was first administered. The changes in serum prolactin and the disturbances of the estrus cycle in the leucine-treated animals persisted for approximately 20 of the 24 days. In a shorter control experiment (seven days), alanine treatment (0.5%) was found to have no effect on prolactin levels. It is concluded that a mild elevation in dietary leucine can affect prolactin synthesis and release and the normal progression of the estrus cycle.

A double-masked comparison of betaxolol vs timolol in the treatment of open-angle glaucoma

We conducted a six-month prospective, double-masked randomized trial comparing betaxolol with timolol at 0.25% and 0.5% concentrations in the treatment of primary open-angle glaucoma in 38 patients. To qualify, patients had to demonstrate an average intraocular pressure in at least one eye of greater than or equal to 26 mm Hg without treatment. The median intraocular pressure was consistently lower in the timolol group than in the betaxolol group (after four weeks of therapy, it was 20.2 mm Hg for timolol vs 22.5 mm Hg for betaxolol; P less than .04). Adjunctive therapy was required in eight patients in the betaxolol group compared to one in the timolol group (P less than .05). Betaxolol appears to be a clinically effective and safe agent in the treatment of open-angle glaucoma. However, the magnitude of the decrease in intraocular pressure with it may not be as great as that with timolol and there may be a greater need for adjunctive therapy with it than with timolol.

Vitamin measurements in pooled blood samples

From 610 blood samples collected in September 1983 in an intervention trial in Huixian, Henan Province, People's Republic of China, which were individually analyzed for retinol, beta-carotene, and alpha-tocopherol levels, 10 pools were formed from 50 individual samples, and the vitamin levels in the merged pools were also measured. Oxidation losses by repeated thawing and refreezing render the absolute levels measured in the pools smaller than the corresponding means of the individual measurements. A very good relative agreement was found between pool levels of retinol and beta-carotene and the respective means. The pooling technique could be a valuable tool in large correlation studies and has possible further applications in case-control studies.

Phosphorylation of prolactin

Rat prolactin exhibits microheterogeneity when examined in electrophoretic systems, running as three isoforms having the same molecular weight but different net charges (prolactins 1, 2, and 3 with isoform 3 being the most acidic). As there is precedent for the phosphorylation of a pituitary hormone and phosphorylation is a common cause of microheterogeneity, we examined the possibility that rat prolactin existed in differentially phosphorylated forms. The investigation included examinations of rat prolactin phosphorylation both in vitro and in vivo. For the in vitro studies, purified rat prolactin was incubated with [gamma-32P]ATP and low levels of each of five purified protein kinases. Phosphorylated rat prolactin was identified by autoradiography of silver-stained one- and two-dimensional gels. For the in vivo studies, rat anterior pituitary cells in primary culture were incubated in the presence of H3 32PO4 for 2 or 12 h, after which time the proteins were extracted from the cells, cold acetone-precipitated, or immunoprecipitated and run on two-dimensional gels. We report the in vitro phosphorylation of rat prolactin by cAMP-dependent protein kinase, casein kinase I, protease-activated kinase I, and the calcium/phospholipid-dependent kinase, that phosphorylation with these kinases results in phosphate incorporation only into isoforms 2 and 3, and the phosphorylation of prolactin in rat pituitary cells in primary culture.

Asbestos and tuberculosis in Trieste, Italy

The distribution of counts of asbestos bodies in lung specimens from 25 persons dying of fibrocaseous tuberculosis was essentially identical to that in age- and sex-matched control subjects. Although tuberculosis mortality has been elevated in the past in cohorts of asbestos workers, asbestos exposure at environmental levels found in a region with a history of heavy asbestos use appears to be unassociated with risk of tuberculosis. Potentiation of the risk of death from tuberculosis may require both a high risk of tuberculosis in the general community and intense personal exposure to asbestos.

Intracellular processing of prolactin

PRL has been reported to exist as a number of mol wt and charge variants. We have attempted to determine the relationships among the charge and lower mol wt variants by two-dimensional gel analysis of pituitary and pituitary cell extracts. Silver-stained gels of the extracts showed three major charge isoforms of 24,000 mol wt PRL (PRLs 1, 2, and 3, with PRL 3 being the most anodic) and what appeared to be an arc of products originating in the region of PRL 3. Each spot in the arc was distinct and represented a small decrease in size (two to eight residues), with a corresponding increase in net negative charge. When primary cell cultures were labeled with [35S] methionine, the three PRL isoforms and arc products were detectable by autoradiography. Western blots of the two-dimensional gels showed the arc products to be immunologically related to PRL. Treatment of the cell cultures with hydroxynorvaline (5 mM), which inhibits processing of pre-PRL to PRL, resulted in doublet spots in the arc. Elimination of protease inhibitors or an increase in temperature during protein isolation had no effect on the relative concentrations of PRL and arc products. Inclusion of standard PRL or [125I]iodo-PRL in the extraction solution did not increase the size of the spots in the arc or produce labeled arc products, respectively. Treatment of the cell cultures with chloroquine (10(-5) M) before and during radiolabeling had no effect on the production of radiolabeled arc products. Analysis of cell culture medium showed at least some of the arc products to be secreted. We conclude that PRL or a PRL-like molecule is processed intracellularly into a number of smaller derivatives. As the arc products accumulate within the cell and are secreted, we suggest that they may be biologically important relatives of PRL.

Mammotroph autoregulation: intracellular fate of internalized prolactin

As part of a study concerning the mechanism of mammotroph autoregulation, the intracellular fate of [125I]iodo rat PRL, internalized by mammotrophs, was determined by quantitative electron microscope autoradiography. Simple grain density (GD) analysis of mammotroph autoradiograms showed that 5 cellular compartments (plasma membrane, Golgi apparatus, secretory granules, nucleus and mitochondria) were significantly labeled and that the labeling pattern in these compartments changed with time. Inclusion of a 25-fold excess of unlabeled PRL inhibited the binding of radiolabeled hormone to mammotrophs by approximately 85%. At no time were any grains found associated with lysosomes and there was no evidence of degradation of the radiolabeled PRL as judged by SDS-polyacrylamide gel electrophoresis or cold perchloric acid precipitation of cell extracts or media samples. Delivery of internalized PRL to a number of specific intracellular organelles suggests that these organelles may serve in the autoregulation of PRL secretion.

Diagnosis and childhood firesetting

This paper presents findings on the relationship of childhood firesetting and DSM-III diagnosis in a representative sample of child psychiatric outpatients (N = 204). Childhood firesetting and the DSM-III diagnosis of conduct disorder are strongly related; they show a significant interaction effect with lessened competence as measured by activities and increased externalizing (undercontrolled) behavior.

Carbonic anhydrase inhibitors induce elevations in human whole-blood zinc levels

The use of carbonic anhydrase inhibitors (CAIs) was associated with mean increases in whole-blood zinc levels of 82 micrograms/dL and 70 micrograms/dL, respectively, in a cross-sectional survey and in a prospective study of patients with glaucoma. The time course of the increase suggests that CAIs induce reticulocyte synthesis of carbonic anhydrase.