Serum cholesterol, fat intake, and breakfast consumption in the United States adult population

Morgan et al demonstrated that adults who consumed ready-to-eat cereals had significantly lower fat and cholesterol intakes than those who ate other foods at breakfast. Not discussed in that study was the effect of breakfast consumption habits on serum cholesterol levels. The NHANES II study of 11,864 adults was used to both verify the Morgan et al results with a different sample and to extend that research by including serum cholesterol. The analysis disclosed that serum cholesterol levels are lowest among adults eating a breakfast that includes ready-to-eat cereal and highest among breakfast skippers.     

Segmental distribution and peptide content of primary afferent neurons innervating the urogenital organs and colon of male rats.

Many visceral afferent neurons contain peptides, which have been proposed as histochemical markers for nerve pathways of particular targets or as transmitter candidates. The former possibility was investigated in the present study. Primary afferent neurons which project to the urinary bladder, distal colon or penis of rats, and the colon of cats were labelled with retrogradely transported fluorescent dyes (Fast Blue, True Blue, or Fluoro Gold). One to six weeks after dye injection into the organs, lumbosacral dorsal root ganglia were removed, treated with colchicine, and processed for immunohistochemical identification of five peptides. Dye-labelled neurons were distributed in an organ-specific manner in the lower lumbosacral ganglia, where colon afferent neurons were almost exclusively found in S1 ganglia, penis neurons primarily in L6, and bladder neurons at both levels. Substance P- (SP), calcitonin gene-related peptide-(CGRP), vasoactive intestinal peptide- (VIP), enkephalin- (ENK), and somatostatin- (SOM) immunoreactivity (IR) were detected in neurons in all lumbosacral ganglia but only some of these peptides were present in a large percentage of labelled neurons. The numbers of peptide-containing neurons innervating each organ were CGRP greater than SP greater than VIP greater than ENK greater than SOM; however some differences were observed in the relative proportions of these neuronal populations between upper lumbar and lower lumbosacral ganglia and between different organs. The major difference seen at the upper lumbar level was amongst the SP-IR neurons, which were common (25-30%) amongst bladder and colon afferent neurons but absent in penis neurons.(ABSTRACT TRUNCATED AT 250 WORDS)     

Innervation of the monotreme gastrointestinal tract: A study of peptide and catecholamine distribution

The distribution of neurons and endocrine cells containing various peptides or catecholamines was examined in the digestive tracts of the echidna (Tachyglossus aculeatus) and the platypus (Ornithorhynchus anatinus). Comparisons were made with published studies in other species in order to obtain a broader view of the phylogenetic distribution and possible functions of gut peptides and catecholamines. Further comparisons between the echidna and platypus were made in light of their different dietary features and gut histology. The distribution of neurons and axons containing catecholamines or various peptides resembled that in other species (such as the frequent appearance of axons containing substance P and vasoactive intestinal peptide in the intestinal mucosa, and axons containing substance P or enkephalins in the circular muscle). In both species, the stomach histologically resembles the esophagus, being aglandular and lined with stratified squamous epithelium. Innervation of these two organs was similar but not identical, with a greater array of peptides found in the gastric muscle. The intestinal mucosa was densely innervated in both species. The platypus small intestine is unusual in having a thick and deeply folded mucosa (but no villi), in which the superficial epithelium is absent or incomplete at many sites; many axons travel close to these luminal surfaces. Many (putative noradrenergic) axons associated with blood vessels contained neuropeptide Y, but there was no evidence for intrinsic catecholamine-containing neurons. Somatostatin and cholecystokinin were present in some endocrine cells, but unlike many mammals, absent in neuronal tissue. These studies have shown that there are many strong similarities between monotremes and other mammals in the distribution and array of peptides found within nervous and endocrine tissues of the digestive tract. However, numerous small differences of the echidna and platypus innervation may be correlated with their different digestive structures. © 1993 Wiley-Liss, Inc.     

Biological responses to overload training in endurance sports

Summary Five subjects undertook 10 days of twice daily interval training sessions on a treadmill followed by 5 days of active recovery. On days 1, 6, 11, and 16 the subjects were required to undertake a test of submaximal and maximal work capacity on a treadmill combined with a performance test consisting of a run to exhaustion with the treadmill set at 18 km · h^–1 and 1% gradient. Also on these days a pre-exercise blood sample was collected and analysed for a range of haematological, biochemical and immunological parameters. The subjects experienced a significant fall in performance on day 11 which had returned to pretraining levels on day 16. Serum ferritin concentrations were depressed significantly from pretraining concentrations at the conclusion of the recovery period while the expression of lymphocyte activation antigens (CD25⁺ and HLA-DR⁺) was increased both after the training phase and the recovery phase. The number of CD56⁺ cells in the peripheral circulation was depressed at the conclusion of the recovery period. Several parameters previously reported to change in association with overload training failing to reflect the decrease in performance experienced by subjects in this study, suggesting that overtraining may best be diagnosed through a multifactorial approach to the recognition of symptoms. The most important factor to consider may be a decrease in the level of performance following a regeneration period. The magnitude of this decreased performance necessary for the diagnosis of overtraining and the nature of an appropriate regeneration period are, however, difficult to define and may vary depending upon the training background of the subjects and the nature of the preceding training. It may or may not be associated with biochemical, haematological, physiological and immunological indicators. Individual cases may present a different range of symptoms and diagnosis of overtraining should not be excluded based on the failure of blood parameters to demonstrate variation. However, blood parameters may be useful to identify possible aetiology in each separate case report of overtraining. An outstanding factor to emerge from this study was the difficulty associated with an objective diagnosis of overtraining and this is a possible reason why there have been new accounts of overtraining research in the literature.     

Cigarette smoke and phagocyte function: effect of chronic exposure in vivo and acute exposure in vitro.

Phagocytic function was studied in mice chronically exposed to cigarette smoke, and the effects of in vitro exposure to cigarette smoke on macrophage activity were also assessed. Cultures of radiolabeled Pseudomonas aeruginosa were employed to investigate phagocyte activity in vivo and in vitro. Mice were exposed on weekdays to fresh cigarette smoke for periods up to 37 weeks and the bactericidal and clearance activity of their lungs was measured. Both pulmonary clearance and bactericidal activity was impaired. The clearance of intravenously injected bacteria from the blood of smoke-exposed mice occurred at the same rate as in control mice, but the accumulation of radiolabel by the liver was decreased. In addition, the rate of elimination of radiolabel from the liver was less than the controls. Macrophages exposed to cigarette smoke in vitro initially had a depressed phagocytic rate, but if phagocytosis over a prolonged period was measured it was eventually enhanced over the rate of control macrophages. The vapor phase of cigarette smoke could also transiently inhibit and then enhance the phagocytic activity.     

Defects in neurofibromatosis 2 protein function can arise at multiple levels

Neurofibromatosis 2 (NF2) is an inherited cancer syndrome resulting from mutations in the NF2 tumor suppressor gene. Analysis of NF2 mutations has revealed some general genotype-phenotype correlations. Severe disease has been associated with mutations that produce a premature termination while more mild disease has been associated with missense mutations. Here, we provide experimental proof for these genotype-phenotype correlations by demonstrating that nonsense mutations fail to produce stable merlin protein while missense mutations result in the generation of merlin proteins defective in negative growth regulation. This inability to suppress cell growth may result from defects in the function of merlin at several levels, including failure to form an intramolecular complex. Based on these findings, we propose a model for merlin growth suppression that provides a framework for analyzing NF2 patient mutations and merlin function.      

Postnatal maturational changes in rat pelvic autonomic ganglion cells: a mixture of steroid-dependent and -independent effects

Androgens have potent effects on the maturation and maintenance of a number of neural pathways involved in reproductive behaviors in males. Most studies in this area have focused on central pathways, but androgen receptors are expressed by many peripheral neurons innervating reproductive organs, and previous studies have demonstrated structural and chemical changes in these neurons at puberty and after castration. We have performed the first electrophysiological comparison of pelvic autonomic ganglion neurons in male rats before and after puberty and following pre- or postpubertal castration. Studies were performed in vitro on intact ganglia with hypogastric and pelvic nerves attached to allow synaptic activation of sympathetic or parasympathetic neurons, respectively. Pelvic ganglion neurons underwent many changes in their passive and active membrane properties over the pubertal period, and some of these changes were dependent on exposure to circulating androgens. The most pronounced steroid-dependent effects were on membrane capacitance (soma size) in sympathetic neurons and duration of the action potential afterhyperpolarization in tonic neurons. Our study also showed that rat pelvic ganglion cells and their synaptic inputs were more diverse than previously reported. In conclusion, this study demonstrated that rat pelvic ganglion neurons undergo considerable postnatal changes in their electrophysiological properties. The steroid dependence of some of these changes indicates that circulating androgens may influence reproductive behaviors at many locations within the nervous system not just in the brain and spinal cord.     

Breast cancer detection: one versus two views

Mammographic examinations of 169 patients with 172 biopsy-proved carcinomas, and of 194 healthy subjects, were interpreted independently and retrospectively by three experienced mammographers, initially as single-view oblique examinations and 6 months later as two-view oblique-cephalocaudal examinations. For the single-view examinations of the cancer patients, 67% of the cancers were correctly recommended for biopsy, additional views were requested for 23%, and a "negative" interpretation was made for 10%. For the single-view examinations of healthy subjects, biopsy was recommended for 7% and additional views were recommended for 32%. For the two-view examinations of women with cancer, 80% of the cancers were correctly recommended for biopsy, additional views were requested for 4%, and a "negative" interpretation was made for 16%. For two-view examinations of healthy subjects, biopsy was recommended for 7% and additional views were requested for only 5%. The authors conclude that single-view screening should not be performed, because it would lead to an excessive number of "call-back" examinations of healthy patients, producing additional cost and anxiety that would outweigh any theoretical benefit.     

Effects of noradrenaline and somatostatin on basal and stimulated mucosal ion transport in the guinea-pig small intestine

Summary Noradrenaline (NA) and somatostatin (SOM) stimulate intestinal water and ion absorption and are found in mucosal nerve fibres and nerve terminals in submucous ganglia of the guinea-pig small intestine. As the main projection of submucous neurons is to the mucosa, NA and SOM might alter mucosal transport either by a direct effect on the epithelium or indirectly, by affecting submucous neurons. In this study these two possible sites of action of NA and SOM have been investigated in mucosa-submucosa preparations of guinea-pig ileum. In addition, the actions of NA and SOM on the secretory responses caused by stimulation of different populations of submucous neurons have been studied. The stimulants of secretion used were a nicotinic agonist, 1,1-dimethyl-4-phenylpiperazinium (DMPP, 10^–5 M), 5-hydroxytryptamine (5-HT, 10^–7 M) and electrical field stimulation (EFS), which activate cholinergic, noncholinergic and mixed populations of submucous secretomotor neurons, respectively.Segments of intestine were dissected free of external muscle and myenteric plexus and mounted in Ussing chambers. Short-circuit current (I _sc) was measured as an indication of net active ion transport across the tissue. NA (10^–8 M) and SOM (>10^–10 M) each caused a decrease in I _sc, indicating a net increase in ion absorption. The NA response was abolished and the magnitude of the SOM response was reduced to 20% by tetrodotoxin (10^–7 M). DMPP, 5-HT and EFS each stimulated nerves that increased I _sc and each of these responses was significantly diminished by NA and SOM; for both NA and SOM the decrease in the DMPP response was significantly greater than the decrease observed in the response to carbachol (10^–6 M). Phentolamine (10^–6 M) abolished all of the effects of NA but caused no change in the SOM effects. These studies have shown that NA and SOM cause similar changes in net ion transport, that their actions are primarily on submucous secretomotor neurons and that NA and SOM can diminish the responses to stimulation of both cholinergic and noncholinergic submucous neurons.In this tissue it is also known that SOM coexists with NA in noradrenergic nerve terminals in the submucosa. However, when applied together, NA and SOM caused no greater decrement in the carbachol and 5-HT responses than would be predicted by adding the separate effects of NA and SOM. Hence there was no obvious interaction between NA and SOM effects on mucosal transport.