Receptors for insulin and insulin-like growth factor-I in the human adrenal gland

Human adrenal glands contain high-affinity receptors for insulin and insulin-like growth factor I (IGF-I). Comparative studies with rat, hamster and human adrenal membranes confirmed that IGF-I receptors are most abundant in rat and hamster adrenals, whereas insulin and IGF-I receptors are present in equivalent numbers in human adrenal glands. Covalent crosslinking studies revealed that the human adrenal gland IGF-I receptor binding subunit migrated on dodecyl sulfate polyacrylamide gels with Mr = 135,000, which is identical to the migration of IGF-I receptor binding subunits isolated from other tissues. Autoradiography of frozen human adrenal slices incubated with [125I]insulin showed prominent, displaceable binding of this radioligand to the zona reticularis, zona glomerulosa, vasculature and medulla; in contrast, [125I]IGF-I binding to human adrenal tissue was most prominent in the zona reticularis and negligible in the medullary region.

Arterial baroreceptor resetting: contributions of chronic and acute processes

1. Pressure threshold (Pth) and suprathreshold pressure sensitivity (Sth) are important measures of the pressure-discharge characteristics of arterial baroreceptors. An in vitro preparation of the rat aortic arch-aortic nerve has been used to assess the influence of extracellular ion concentration, distensibility, smooth muscle activation and rapid resetting on single fibre baroreceptor discharge. 2. Changes in extracellular cations alter Pth and Sth in a reciprocal manner, suggesting that these two properties share common excitatory mechanisms probably at the level of membrane ion conductance channels. 3. During normal development and ageing in normotensive rats, Pth and blood pressure are fairly constant even during periods of greatly changing aortic distensibility. Sth increases progressively to maturity and then decreases somewhat with advanced age. 4. During hypertension, changes in distensibility in spontaneously hypertensive rats do not account for changes in Pth and Sth. 5. The capacity of arterial baroreceptors to rapidly reset during acute changes in the conditioning mean arterial pressure is not altered by chronic resetting, decreases in distensibility or by differences in the initial Pth or Sth of individual baroreceptors. 6. Within the maximal physiological or pathophysiological range, the prevailing or conditioning mean arterial pressure appears to be the most potent modulator of arterial baroreceptor discharge.

[Differences in length and weight growth patterns between urban and rural infants]

Mixed longitudinal data of length and weight growth from 595 rural and 337 urban infants were analysed. Count models were fitted to the means of length and weight in different ages, sexes and feedings separately. The curve fitting to the data was rather satisfactory. Comparison of model parameters between urban and rural infants suggested that rural infants had a higher length level at birth but lower accelerative growth afterwards than urban ones, which was even more obvious in breast-fed infants. The difference in birth weight between them was not significant; and the urban infants had a faster linear growth velocity than rural ones. These results might be caused by the fact that food supplementing in urban infants was significantly earlier and better than in rural ones.

Carcinoid tumor of the testicle

Carcinoid tumors commonly are found in the gastrointestinal tract; they rarely are found in the testicle. An illustrative case is presented and the entity discussed. Variables regarding prognosis are reviewed.

Interaction among unitary spike trains: implications for whole nerve measurements

Interaction among action potential trains was examined in electroneurograms (ENGs) from filaments containing several fibers. In an in vitro preparation, increasing aortic pressure generated trains of action potentials (spikes) from regularly discharging aortic baroreceptors. Multifiber records were electronically sorted, and spikes from each separate baroreceptor were identified. "True" discharge rates, measured as the instantaneous frequency of the sorted records, were compared with the results of three quantitation approaches commonly used for multifiber or whole nerve activity in mass ENGs: "spike" counts per unit time, ENG voltage integration, and normalizations of counts or integration. Even in ENGs containing only two active baroreceptors, numerous interactions of the two spike trains occurred. Of 33 paired recordings (66 baroreceptors), 77.3% of the individual baroreceptors had spike trains that could not be clearly discriminated because of interactions with signals from other baroreceptors. Virtually all baroreceptors (96.3%) in nine three-fiber ENGs (27 baroreceptors) showed evidence of missed spikes. Corrected or true spike rates were always greater than activity rates measured by simple counting. Similarity of discharge frequencies in the different baroreceptors was the most important determinant of the rate of voltage signal interaction. Simple count or integration methods underestimated slopes of pressure-response curves and peak activity values by 20-40% compared with sorted instantaneous frequency. Not all coincidence of action potentials in the ENG resulted in simple additions of peak voltages. We conclude that simple counting and integrative techniques substantially underestimate multifiber nerve activity and such quantitation techniques should be used cautiously, particularly in experimental comparisons across groups of animals.(ABSTRACT TRUNCATED AT 250 WORDS)

[A study on traditional processing methods using drug juice]

The traditional processing with drug juice has a long history, rich contents, rigid regularities and a variety of method. It is one of the important processing methods in Chinese medicine. To systematize and make better use of the traditional methods of processing drug juices, this paper has conducted an investigation from such angles as historical background, approximate rules of composing and clinical application.

Interaction between mitochondria and the nucleus

The interaction between the mitochondrial and the nuclear genome is in part mediated by proteins (and possibly also RNAs) which are encoded in the nucleus and imported into mitochondria. We are beginning to understand how proteins can penetrate across both mitochondrial membranes and how some of these proteins can regulate the expression of specific mitochondrial genes.

Import of proteins into yeast mitochondria: the purified matrix processing protease contains two subunits which are encoded by the nuclear MAS1 and MAS2 genes

We have purified the metalloprotease which is localized in the soluble matrix space of Saccharomyces cerevisiae mitochondria and cleaves the amino-terminal matrix-targeting sequences from imported mitochondrial precursor proteins. The enzyme consists of two loosely associated non-identical subunits of mol. wt 48,000 and 51,000, respectively. Attempts to separate the two subunits from each other caused loss of activity. The smaller subunit had been identified as the product of the nuclear MAS1 gene (Witte et al., 1988). The larger subunit is now identified as the product of the nuclear MAS2 gene.

Localization of Bacillus subtilis sacU(Hy) mutations to two linked genes with similarities to the conserved procaryotic family of two-component signalling systems

Mutations in the sacU region have a pleiotropic phenotype. Certain mutations designated sacU(Hy), for example, express degradative enzymes at high levels, are able to sporulate in the presence of glucose, have severely reduced transformation efficiencies, and are nonmotile. We isolated and sequenced the sacU gene region of Bacillus subtilis. Two open reading frames were found in the sacU region, and sacU(Hy) mutations were localized to both of these open reading frames. The two open reading frames have similarities to two widespread families of proteins that mediate responses to environmental stimuli.

High-frequency switching in Dictyostelium

A high-frequency switching system is demonstrated to exist in Dictyostelium discoideum. Switch phenotypes are distinguished by colony morphology and include changes in developmental timing as well as blocks in morphogenesis. The switching system exhibits the following characteristics: (1) a "low" spontaneous frequency of switching (approximately 10(-2] in the parent strain; (2) stimulation of the basal level of switching roughly fivefold with low doses of ultraviolet light; (3) "high" spontaneous frequencies of switching (as high as 10(-1] in particular variant strains; (4) high spontaneous frequencies of interconvertibility between variant phenotypes; (5) high spontaneous frequencies of reversion to the wild-type phenotype; (6) a set of reproducible switch phenotypes; (7) heritability of switch phenotypes; and (8) a rough correlation between switch phenotype and switching frequency. The extraordinary similarity between the switching systems in D. discoideum and Candida albicans is discussed.

Distribution of receptors for insulin and insulin-like growth factor I (somatomedin C) in the adrenal gland

Rat adrenal glands contain cell surface high-affinity receptors for several peptide hormones. Receptors for IGF-I were abundant in this tissue, but receptors for insulin were relatively scarce. The behavior of adrenal membrane IGF-I receptors in radioligand binding assays was similar to the behavior of IGF-I receptors from other tissues, with a KD congruent to 6.2 x 10(-9) M. Covalent cross-linking studies with [125I]IGF-I revealed an IGF-I receptor alpha-subunit with Mr congruent to 135,000 on dodecyl sulfate polyacrylamide gel electrophoresis under reducing conditions, as well as a smaller radiolabeled peptide, Mr = 116,000. In contrast, little binding of [125I]insulin to adrenal membranes was observed and no labeling occurred in cross-linking studies using [125I]insulin. These results contrast with the findings of whole-body autoradiographic studies that indicated substantial binding of [125I]insulin to adrenal glands and suggest that IGF-I, rather than insulin, may play a critical role in the growth and development of the adrenal gland.

Distribution-free estimation of age-related centiles

A method is described for calculating age-related centiles which makes no assumption about the nature of the distribution of the measurement at a fixed age.

Characterization and mapping of the Bacillus subtilis prtR gene

A gene from Bacillus natto encoding a 60-amino-acid peptide has been previously described that, when cloned on a high-copy plasmid in B. subtilis, enhances production of alkaline protease, neutral protease, and levansucrase. An identical gene was isolated from B. subtilis and caused a similar phenotype when placed on a high-copy plasmid. Genetic mapping localized this gene near metB, distant from other pleiotropic genes causing similar effects. Deletion of this gene from the B. subtilis chromosome had no obvious phenotypic effect.

CSF brain creatine kinase levels and lactic acidosis in severe head injury

The posttraumatic creatine kinase-BB isoenzyme (CKBB) activity and lactate concentration in ventricular cerebrospinal fluid (CSF) have been studied in 29 patients with severe head injuries. The CKBB activity reaches its maximum a few hours after trauma, and has a monoexponential drop with a half-time of approximately 10 hours. Ventricular CSF lactate concentration continues to rise in patients with a poor outcome, and decreases only slowly and inconsistently in most of the other patients. Thus, increase of lactate in the ventricular CSF is not, like CKBB, a direct one-stage consequence of the trauma but is due to continuous production from a derangement of metabolism caused by the trauma. Since even higher ventricular CSF lactate levels can be survived when not caused by head injury, and since no significant pH changes were related to the ventricular CSF lactic acidosis in these artificially ventilated patients, it is concluded that ventricular CSF lactic acidosis is indicative of a severe, although not necessarily intractable, disturbance of brain function associated with intracellular lactate production and acidosis.

Identification of the pleiotropic sacQ gene of Bacillus subtilis

The sacQ gene of Bacillus subtilis, a pleiotropic gene affecting the expression of a number of secreted gene products, has been identified as a small 46-amino-acid polypeptide. The increased expression of this polypeptide in strains carrying the sacQ36 allele, or in strains carrying the sacQ gene on a high copy plasmid, appears to be responsible for the phenotype of higher levels of proteases seen in these strains. A deletion of the sacQ gene had no apparent phenotype, indicating that it is not an essential gene.

Nucleotide sequence of the amylase gene from Bacillus subtilis

The gene coding for amylase (EC.3.2.1.1) has been isolated and sequenced from Bacillus subtilis by cloning in lambda Charon4A and pBR322. The entire coding sequence and large preceding and following regions, comprising the presumed transcriptional and translational regulatory regions, were sequenced. The coding sequence shows a large open reading frame with a translated molecular weight of 72,800 and a presumed signal sequence of approximately thirty-two amino acids. When the intact gene is present in Escherichia coli, it confers the ability to degrade starch, indicating that the gene is expressed in a functional state.