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Biomedical subjects

B Beck

Publications and source records attributed to B Beck.

At least 91 records · Page 5Linked to original sources
PubMed1992

Changes in hypothalamic neurotensin concentrations and food intake in rats fed a high fat diet.

Neurotensin (NT), a peptide present both in the brain and in the gastrointestinal tract, has potent anorexigenic effects when centrally injected in rats and is secreted after fat ingestion. High fat diets are often associated with increased energy intake. The aim of this study was therefore to evaluate the role of neurotensin in the feeding behaviour of rats fed on a high fat (HF) diet. Adult Long-Evans rats were fed for two weeks either a control (C) well-balanced diet (n = 10) or a fat-rich diet containing about two-thirds of its energy as fat (margarine and peanut oil; n = 10). Neurotensin was measured by a specific radioimmunoassay in the plasma and in several microdissected brain nuclei involved in the regulation of feeding behaviour. Ingestion of the HF diet induced an increased body weight gain (47.6 +/- 7.7 g (HF) vs. 37.6 +/- 9.3 g (C); P less than 0.05) and an increased energy intake (+ 7.2%; P less than 0.05). Plasma fasting NT concentrations were not affected by the HF diet. In the hypothalamus, significant decreases in NT concentrations were measured in the HF rats in two nuclei important in the regulation of food intake, i.e. the paraventricular nucleus (1.72 +/- 0.16 (HF) vs. 2.27 +/- 0.15 (C) ng/mg protein; P less than 0.05) and the lateral hypothalamus (1.87 +/- 0.16 (HF) vs. 2.37 +/- 0.19 (C) ng/mg protein; P less than 0.05). On the other hand, no variations were measured in the ventral tegmental area, an important site for the metabolism and regulatory action of neurotensin and in other hypothalamic nuclei.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Cholecystokinin, neurotensin and corticotropin-releasing factor, three important anorexic peptides].

This paper updates the informations on the three most important anorexigenic peptides: cholecystokinin, neurotensin and corticotropin-releasing factor. Their peripheral and/or central effects on food and water intakes as well as on dietary preferences are detailed. Their mechanisms of action and regulation are examined. This includes the interactions with classical neurotransmitters (norepinephrine, dopamine, etc...) as well as the description of the brain nuclei and neuronal networks involved. Finally, their variations in disturbed feeding behavior (hyperphagia, anorexia) in man or in animal models are reviewed.

Animals↗
PubMed1991

Reactivity of fungal organisms in tissue sections using anti-mycobacteria antibodies.

Sixty-four cases of deep fungal infections diagnosed using PAS or silver stains and 18 control cases of sarcoidosis, M. tuberculosis and M. leprae infection were stained using commercial polyclonal antibody raised against M. paratuberculosis (MP), M. Duvalii (MD), and Bacillus Calmette-Guerin (BCG). Nine of 13 cases of sporotrichosis stained positively using anti-MP antibody only; 13 of 14 cases of histoplasmosis stained with anti-BCG, anti-MD, and anti-MP; seven cases of cryptococcosis had only focal staining of rare individual organisms within masses of negative organisms; seven of eight cases of coccidioidomycosis stained predominantly with anti-BCG and anti-MP; eight cases of aspergillus had focal (1 to 5% of organisms) staining of hyphae with anti-BCG and anti-MD; and four of 12 cases of Candida infection showed focal nonspecific staining with both antibodies and nonimmune serum. Control cases of sarcoidosis exhibited no staining with any of the three antibodies, whereas cases of mycobacterial infection showed staining of bacilli and intracellular debris with all three antibodies.

Antibodies, Bacterial↗
PubMed1991

[The 32P-test in the diagnosis of intraocular melanoma--an obsolete study method?].

Results of the 32P uptake test for the diagnosis of choroidal melanoma in 41 patients are reported. The sensitivity was 80%, the specificity 86%, if a count rate ratio of more than 1.4 between tumor and normal tissue was considered as pathological. Ratios between 1.4 and 1.6 ought to be considered as equivocal in which case specificity increases to 90%. The 32P uptake test still remains a method of clinical relevance in the diagnosis of choroidal melanoma.

Choroid Neoplasms↗
PubMed1990

Diurnal rhythm of neuropeptide Y-like immunoreactivity in the suprachiasmatic, arcuate and paraventricular nuclei and other hypothalamic sites.

The diurnal rhythm of neuropeptide Y (NPY)-like immunoreactivity was examined in 9 discrete hypothalamic sites of rats maintained on a 12:12 h light/dark cycle. Significant bimodal rhythms of NPY concentration were detected in the suprachiasmatic and arcuate nuclei, with significant peaks just prior to onset of the nocturnal period and also at onset of the light period. In the parvocellular division of the paraventricular nucleus, a unimodal NPY peak was observed prior to dark onset. No diurnal rhythm was seen in the magnocellular division of the paraventricular nucleus, nor in 5 other hypothalamic areas examined.

Animals↗
PubMed1990

Rapid and localized alterations of neuropeptide Y in discrete hypothalamic nuclei with feeding status.

Neuropeptide Y (NPY) is believed to regulate the normal eating behavior and body weight in rats via central mechanisms. We have investigated whether NPY, which stimulates food intake, may in turn be modified by the nutritional state of the animals. Thus the impact of food deprivation (FD) (48 h) and subsequent refeeding on the levels of NPY in discrete hypothalamic areas was examined in this study. The results showed site specific change in only 3 of 7 hypothalamic sites. A 5-fold increment in NPY was reported in the paraventricular nucleus (PVN) and a 10-fold increase was observed in the arcuate nucleus-median eminence (ARC-ME). While subsequent refeeding for 6 h reversed the effect of FD in the ARC-ME, the levels of NPY in the PVN remained high in the refed rats. The perifornical lateral hypothalamus displayed a different pattern, namely, a significant increase in NPY content in refed as compared to satiated and deprived rats. The NPY levels in 4 other hypothalamic sites, namely, the dorsomedian, ventromedian, supraoptic and suprachiasmatic nuclei, and two extrahypothalamic sites, namely caudate nucleus and nucleus accumbens, showed total resistance to any change following deprivation and refeeding. These data emphasize the important and specific role of the paraventricular and arcuate nuclei in NPY's regulation of food intake and provide support for the idea that the variations of hypothalamic NPY after food deprivation reflect a specific physiological response of feeding regulatory system to alterations in the animal nutritional state and body weight.

Animals↗
PubMed1990

Hypothalamic neuropeptide Y (NPY) in obese Zucker rats: implications in feeding and sexual behaviors.

Neuropeptide Y (NPY), a peptide of the pancreatic polypeptide family, is actually considered to be the most potent stimulator of food intake in rats when centrally injected. It has also suppressive effects on several components of sexual behavior. It was measured in discrete microdissected brain nuclei in obese hyperphagic Zucker fa/fa rats also characterized by a deficient reproductive function, as well as in their lean homozygous (Fa/Fa) and heterozygous (Fa/fa) counterparts. When compared with the lean (Fa/Fa) rats, NPY concentrations were significantly increased in the obese rats in the arcuate nucleus-median eminence (ARCME, +300%), in the paraventricular (PVN, +60%), suprachiasmatic (SCH, +90%), accumbens (+100%) and supraoptic (+40%) nuclei, as well as in the median preoptic area (MPOA, +70%). As PVN is one of the most important nuclei involved in the control of food intake and one site of NPY action, the high levels found in this nucleus might be a major component at the origin of hyperphagia in the obese animals. Food intake might be overstimulated by a sustained production of NPY as shown by the high concentrations found in the ARCME. NPY might also intervene in the pattern of food intake, for NPY contents were also largely modified in the SCH, the nucleus regulating feeding periodicity and in the MPOA, which is possibly involved in the regulation of energy balance. Finally, as the MPOA is the only site of action of NPY on sexual behavior, the higher levels measured in this area might contribute to the defective reproductive function of the obese Zucker fa/fa rat.

Animals↗
PubMed1990

Influence of diet composition on food intake and hypothalamic neuropeptide Y (NPY) in the rat.

Ingestion of a high carbohydrate (HC) or high fat (HF) diet induces obesity in association or not with modifications of the feeding behaviour. Effects of diet composition on NPY, a powerful stimulant of weight gain and food intake (particularly carbohydrates), are not known. That is why we measured NPY in 10 microdissected brain nuclei of rats fed either a HC diet (69% of energy from carbohydrates), a HF diet (68% of energy from fat) or a control well-balanced diet (54% of energy from carbohydrates; 30% of energy from fat) during a 14-day period. Total caloric intake was significantly greater (+12%) in rats fed on the HF diet than in the control and HC rats. HF rats also gained more weight than the two other groups (47.5 +/- 2.4 g vs 37.6 +/- 2.6 g (control) and 29.1 +/- 1.4 g (HC); p less than 0.001). NPY variations were restricted to two hypothalamic areas. In the parvocellular part of the paraventricular nucleus, NPY was smaller with the HC diet than with the HF diet (42.1 +/- 2.3 vs 49.5 +/- 2.7 ng/mg protein; p less than 0.05). A decrease was observed in the lateral hypothalamus with the HF diet when compared with the control diet (11.3 +/- 0.7 vs 14.6 +/- 1.1 ng/mg protein; p less than 0.05). No variations were observed either in other hypothalamic nuclei such as arcuate, dorsomedian, ventromedian or suprachiasmatic nuclei or in extra-hypothalamic areas such as the ventral tegmental area or submamillary bodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Cerebral involvement in Whipple's disease].

Whipple's disease is a rare protean disease. Cerebral involvement occurs in ten percent of the cases. CCT findings in two patients with cerebral symptoms are presented. There was an unspecific atrophy in one patient. Patient two had hydrocephalus occlusus and a temporal lesion enhanced by contrast agent. A specific diagnosis on the sole basis of the CCT without additional clinical data does not seem possible.

Brain Diseases↗
PubMed1990

Polyclonal antibodies raised against Bacillus Calmette-Guerin, Mycobacterium duvalii, and Mycobacterium paratuberculosis used to detect mycobacteria in tissue with the use of immunohistochemical techniques.

Commercially available polyclonal antibodies raised against strains of mycobacteria were used to detect organisms in tissue sections from 34 cases of tuberculosis, leprosy, and atypical mycobacteria. Thirty-two cases of fungal infections, granulomatous inflammation, and sarcoidosis were used as negative controls. Sections stained with the use of antibodies raised against Bacillus Calmette-Guerin (BCG), Mycobacterium duvalii (MD), and Mycobacterium paratuberculosis (MP) were compared with Kinyoun and Fite-stained tissue sections. In caseating granulomata, clumps of mycobacterial debris, cells, and cell fragments stained. In histiocytic granulomata of mycobacterial infections, histiocyte cytoplasm contained both organisms and debris. The three antibodies showed cross-reactivity against the four groups of mycobacteria tested. Mycobacterial staining using immunoperoxidase was apparent in most cases at low-power (scanning) magnification. Thirty-two of 34 cases of mycobacterial infection, including all 24 Kinyoun-Fite-positive cases, were positive for immunoreactive organisms and debris using anti-MD, anti-BCG, and/or anti-MP. Eight of ten cases of culture-proven mycobacterial infection, in which Kinyoun and Fite stains were negative, had immunoreactive organisms or antigen with anti-BCG, MD, or MP. The antibodies also stained organisms in five cases of sporotrichosis in which the organisms were identified as yeast forms in tissue sections.

Antibodies, Bacterial↗
PubMed1990

Hyperphagia in obesity is associated with a central peptidergic dysregulation in rats.

Hyperphagia and obesity are often associated, and the origins of the biochemical modifications leading to these syndromes might be in the hypothalamus. Indeed, food intake is regulated by numerous neuropeptides in various hypothalamic nuclei, including the paraventricular (PVN), arcuate (ARC), ventromedian (VMN) and suprachiasmatic (SCH) nuclei. Among these peptides, neuropeptide Y (NPY) is the most potent inducer of food intake whereas neurotensin (NT) decreases food intake. We measured these two peptides in microdissected hypothalamic nuclei in obese Zucker rats that ate 30% more food than their lean counterparts. Neuropeptide Y and neurotensin levels varied in opposite directions: In the hyperphagic obese Zucker rats, the NPY concentrations were significantly greater than those in the lean normophagic rats in the ARC (+30%), PVN (+60%) and SCH (+94%) nuclei, whereas the NT levels were significantly lower in the ARC (-40%), PVN (-31%) VMN (-66%) and SCH (-47%) nuclei. Both these variations tend to increase food intake. Feeding periodicity might also be modified because large variations of the two peptides have been measured in the supra-chiasmatic nucleus, which is considered the most important regulator of feeding rhythm. The results reinforce the hypothesis that hyperphagia in obesity is associated with a biochemical modification in the central nervous system because the peripheral status of NT and NPY was not modified in the obese rats. Because levels of other hypothalamic peptides, such as opioid peptides and somatostatin, are also slightly modified, it can be concluded that hyperphagia in obesity is associated with a central peptidergic dysregulation. Research on drugs reacting specifically with the receptor of these peptides might have interesting implications for the treatment of hyperphagia and, therefore, of obesity.

Animals↗
PubMed1990

A mortality study of a cohort of slate quarry workers in the German Democratic Republic.

Following reports from other countries indicating an excess risk of lung cancer among silicotics, a historical cohort of workers employed for at least one year at a company in charge of slate extraction and processing during the period 1953-1985 in the German Democratic Republic has been constructed and followed up for mortality from 1970 to 1985. The results of the study show a mortality excess for infectious and respiratory diseases. The overall lung cancer mortality is not in excess but shows a tendency to increase with time since first exposure. A mortality excess from lung cancer is concentrated among workers receiving compensation for silicosis, suggesting a possible carcinogenic risk for individuals suffering from this pathological condition.

Cause of Death↗
PubMed1990

[Zonographic study of pleural lesions due to asbestos dust].

Results of zonographic examination of the chest were compared with roentgenographic data in 34 patients with asbestos hyalinosis of different severity. The zonographic substrate of pleural hyalinosis are echo-poor intermediate spaces that are visualized bilaterally in different parts of the pleura. It was established that zonographic examination is more sensitive than roentgenography for revealing pleura hardening. Chest zonography is recommended to reveal of exclude pleura hyalinosis induced by asbestos in the absence of typical asbestos-induced changes on the pulmonary x-ray picture.

Aged↗
PubMed1990

[Occupational and non-occupational effects of asbestos].

Forty-eight cases of mesothelioma from the National Cancer Register, and 19 cases of pleural plaques were investigated for non-occupational exposure to asbestos, and compared with results obtained in earlier studies on occupational asbestos-induced lesions. The results of the investigation confirmed reports in the literature indicating that even in the non-occupational area, asbestos represents a non-negligible risk, in particular for diseases of the lungs. Individual causes proved to be the cleaning by members of the family of working clothes contaminated with asbestos in 46% of the cases, followed by the use of asbestos-containing materials in the household (20.9%) or in connection with leisure activities (14.9%). In addition, exposure to asbestos fibre emissions of people living close to an asbestos-processing plant were observed. Recognition of the condition as an occupation-related disease is not possible. The consequence to be drawn from these data is that, in accordance with present regulations, the use of asbestos-free materials in the home and in the area of leisure activities must be promoted. In this way, such lesions can be avoided in the future.

Air Pollutants, Occupational↗
PubMed1989

[Ambulatory indirect long-term blood pressure measurement in primary and secondary hypertension].

Ambulatory 24 hour blood pressure measurements were performed in 21 patients with various forms of secondary hypertension and were compared with the blood pressure profile of a matched group of patients with primary hypertension. Patients with renovascular (n = 8) and renoparechymal hypertension (n = 8), and with primary hyperaldosteronism (n = 4) showed no significant fall in systolic blood pressure during the sleeping period (00-03 a.m.) and in systolic and diastolic blood pressure in the early morning (06 a.m.) as compared with essential hypertensives. However, in a single case of hypertension due to coarctation of the aorta the 24 hour blood pressure profile is not different from essential hypertension. Thus, ambulatory 24 hour blood pressure recording is a good method for screening secondary forms of hypertension.

Ambulatory Care↗
PubMed1989

Subpopulations of somatostatin 28-immunoreactive neurons display different vulnerability in senile dementia of the Alzheimer type.

We tested whether the vulnerability of somatostatin (SST) neurons in senile dementia of the Alzheimer type (SDAT) depended upon their co-localization with neuropeptide Y (NPY). Density estimates of SST28- and NPY-immunoreactive neurons and percentage of double-labeled SST-NPY neurons were obtained in the cortex (areas 9 and 25) and the bed nucleus of stria terminalis (BST), in 6 SDAT and 5 control cases. Counts of senile plaques (SP) and neurofibrillary tangles (NFT) were done on thioflavin S stains. In both cortical areas, a decrease in the density of SST28-IR neurons was found in SDAT cases (-60% in area 25 and -80% in area 9), whereas density of NPY-IR neurons was unchanged. Accordingly, the proportion of single-labeled SST neurons decreased; this decrease was significantly correlated with SP (r = -0.89, P less than 0.001). We conclude that single SST-IR neurons, in cortical layers II-III, and V, are preferentially lost relative to co-localized SST-NPY neurons. In the BST, no significant reduction of SST-IR, NPY-IR neurons nor of the percentage of single labeled SST neurons was found, despite the presence of SP. Thus one subpopulation of SST neurons, defined by associated neurochemical characters (not co-localized with NPY nor with NADPH diaphorase) and by topography (cortical layers III and V) appears to be particularly vulnerable in SDAT. The potential importance of their position in neural circuitry is emphasized.

Aged↗
PubMed1989

A comparison of double-tuned surface coils.

The combined acquisition of proton images and localized spectra is considered essential to the practical application of NMR techniques to human and animal research. Double-tuned surface coils which have been introduced to the literature are intended to address the problem; however, a careful evaluation of available designs is lacking. The "trap" method, the loop gap resonator design, and the transformer-coupled double-tuned design are evaluated here using bench tests of signal intensity and Q as well as signal-to-noise measurements on a 2-T imager/spectrometer. Comparisons are made relative to optimized single-tuned circuits of the same size for both protons at 85 MHz and phosphorus at 34 MHz. The results suggest that the "trap" design and the transformer coupled design are very efficient (98%) in the low-frequency mode (34 MHz) while the loop gap resonator is relatively inefficient (82%). In the high-frequency mode (85 MHz) the loop gap resonator is 75% efficient while the "trap" design and the transformer coupled coil are closer to 50% efficient.

Equipment Design↗