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Biomedical subjects

J Rossi

Publications and source records attributed to J Rossi.

At least 91 records · Page 5Linked to original sources
PubMed1985

Peptide- and non-peptide-containing unmyelinated primary afferents: the parallel processing of nociceptive information.

Primary afferent C fibres can be subdivided into a number of subgroups on the basis of cytochemistry or receptor binding characteristics. Numerous peptides have been localized to dorsal root ganglia, yet these appear to be only found in approximately 50% of small perikarya. A large proportion of the remaining small cells do not contain peptides but are identifiable in rodents by their content of a fluoride resistant acid phosphatase. Attempts have been made to correlate particular biochemical types with particular receptive field profiles, with rather modest success. As an alternative we suggest, principally from an analysis of skin afferents, that peptide- and non-peptide-containing afferents are two distinct C fibre pathways innervating similar peripheral structures and conveying similar information, but to different areas within the dorsal horn. Morphological evidence also suggests that these two subsystems form either glomerular or simple synaptic arrangements in the dorsal horn. The significance of parallel pathways for the processing of nociceptive information is briefly discussed.

Acid Phosphatase↗
PubMed1985

Radiation doses due to long-range transport of airborne radionuclides released by a reactor accident--effects of changing dispersion conditions during transport.

This paper presents a model for the estimation of radiation doses due to long-range transport of airborne radioactive material released into the atmosphere by a reactor accident. The paper includes examples of calculated doses in situations where the weather changes during the transport path. These examples show that changing dispersion conditions, such as rain, may bring about considerable changes in the individual doses. Short-term changes in turbulence, mixing depth and wind speed during the transport path also have a strong influence on doses.

Accidents↗
PubMed1983

The role of brain norepinephrine in clonidine suppression of isolation-induced distress in the domestic chick.

Distress vocalizations (DV) induced by social isolation were measured in 1-day-old domestic chicks after intracerebroventricular injections of drugs believed to exert their effects through the noradrenergic system. The alpha-adrenoreceptor agonist clonidine reliably suppressed DV rates at doses low as 0.08 micrograms. When given alone, phentolamine, phenoxybenzamine, propranolol, sotalol, and yohimbine (adrenoreceptor antagonists) did not reliably alter DV rates at doses that were not toxic. The clonidine DV suppression was reliably reversed by yohimbine (1.75 micrograms), but by none of the other adrenoceptor antagonists or naloxone. 6-Hydroxydopamine at doses as high as 120 micrograms, which essentially eliminated forebrain norepinephrine, failed to suppress DV rates reliably when given alone and, when given in combination with clonidine (0.1 micrograms) or morphine (0.05 micrograms), failed to reverse the severe DV suppression imposed by these drugs. The results suggest that clonidine suppresses DV rates in or by some means other than prejunctional alpha 2-adrenoreceptor stimulation.

Animals↗
PubMed1983

Fenfluramine anorexia: a peripheral locus of action.

In a series of feeding pattern studies, amphetamine was shown to produce a period of complete anorexia often followed by a broken nibbling pattern of eating. Fenfluramine produced a regular feeding pattern in which a depressed meal size was not compensated for by an increase in meal frequency. The disproportionate lengthening of the post-meal interval relative to meal size was accompanied by a decrease in the rate of gastric emptying. Fenfluramine was most effective in lengthening post-meal interval when administered immediately after a meal, and was progressively less effective when the injection was delayed, allowing time for gastric emptying to occur. Amphetamine was shown to have similar but less pronounced effects, corresponding to its weaker effects on gastric emptying. Midbrain raphe lesions that abolished the fenfluramine effect on short-term intake of food-deprived rats did not attenuate fenfluramine's effect on gastric emptying, nor did the lesions attenuate the anorectic effect of fenfluramine on ad lib food intake. Lateral intracerebroventricular administration of fenfluramine not reduce feeding. These results suggest that fenfluramine controls feeding primarily by short-term signals related to food in the upper gastro-intestinal tract.

Animals↗
PubMed1982

An improved pharmacological procedure for depletion of noradrenaline: pharmacology and assessment of noradrenaline-associated behaviors.

A pharmacological procedure which initially depletes noradrenaline (NA), dopamine (DA) and 5-hydroxytryptamine (5-HT) but permits repletion of DA and 5-HT was used to evaluate the role of NA in feeding behavior and intracranial self-stimulation behavior. The rapid-onset 'reserpine-like' vesicular depletion drug RO 4-1284 reduced NA and 5-HT 99% and DA 90% in rat forebrain within 1 h after administration with complete repletion of all amines occurring within 6 to 12 h. Treatment with the dopamine-beta-hydroxylase inhibitor FLA-63 significantly reduced NA (maximum depletion 42%) but not DA or 5-HT over the 12 h period of evaluation. The two drugs together produced a specific depletion of NA. Forebrain levels of NA in subjects pretreated with FLA-63 then given RO 4-1284 0.5 h later were reduced to 2% of control values for 8 h while vesicular stores of DA and 5-HT were repleted 77% and 93%, respectively, within 8 h after administration. Selective depletion of NA, in this manner, reduced deprivation induced food intake and lateral hypothalamic self-stimulation.

2H-Benzo(a)quinolizin-2-ol, 2-Ethyl-1,3,4,6,7,11b-↗
PubMed1982

The role of norepinephrine in feeding behavior.

When dopamine-beta-hydroxylase is inhibited with FLA-63 (10 mg/kg) free feeding behavior is disrupted in satiated rats. While the average number of meals taken was not different from vehicle injected controls, meal size was decreased 58% in the first 9 hr after treatment with FLA-63. In starved animals, FLA-63, when given alone, produced little effect on feeding behavior, even though norepinephrine depletion was in excess of 40%. When given in combination with RO4-1284 (5 mg/kg), a vesicular reuptake inhibitor, feeding was reduced to 16% of control intake and norepinephrine was specifically depleted 99%. Feeding was reliably reinstated in animals which received FLA-63 plus RO4-1284 with either dl-threo-DOPs, a metabolic precursor to NE, or direct intrahypothalamic injections of NE. These findings suggest that the feeding inhibition observed after treatment with FLA-63 plus RO4-1284 is due to disruption of transmission in brain NE systems. A non-anorectic dosage of L110-140 (3.73 mg/kg), a specific FLA-63. Taken collectively, these findings suggest that the primary role of NE in feeding is maintenance of the consummatory response and that these effects are expressed in relation to activity in other neurochemical systems.

2H-Benzo(a)quinolizin-2-ol, 2-Ethyl-1,3,4,6,7,11b-↗
PubMed1981

The tyrT locus: termination and processing of a complex transcript.

The tyrT locus of E. coli contains a 208 bp spacer region that separates two copies of sequence encoding tRNATyr1. The spacer includes a 120 bp sequence that is homologous to a sequence that is repeated three times in the distal portion of the tyrT locus. The tyrT locus possesses a graded set of transcription termination sites that are spaced at 180 base intervals, corresponding to the distal repeated gene structure. The major termination site occurs within the second repeat unit, 225 bases beyond the mature tRNA sequences. In the presence of a temperature-sensitive rho protein there is increased read-through at this site to a termination site located 180 bases downstream in the third repeat and to several termination sites even further downstream. The primary native transcript, in the region distal to the second tRNA, carries the information for a low molecular weight, extremely basic protein. Although analogous coding sequences are present in the spacer and other repeat units, because of single base substitutions these sequences are pseudogenes. The parallel between the tyrT and TyrU gene clusters is discussed in relation to dual function transcripts that specify both tRNA and protein.

Bacterial Proteins↗
PubMed1981

D-glucose infusions into the basal ventromedial hypothalamus and feeding.

Following symmetrical bilateral infusion of D-glucose into the basal ventromedial hypothalamus (BVMH), using Alzet minipumps (1 microliter/h of 10% D-glucose for 6 days), average daily food intake was reduced by 27% for the period of treatment. Symmetrical bilateral infusions into the posterior medial hypothalamus had a transitory effect on feeding, as did asymmetrical and unilateral infusions. Infusion of L-glucose into the BVMH did not yield a chronic reduction in food intake. Included in the infused solutions were tracer amounts of [14C]glucose, [14C]proline or [14C]leucine to permit radioautographic estimations of infusate dispersal in the brain and axonal transport patterns from the infusion sites. Infusions were generally well-restricted to 1-1.5 mm of the cannulae tips, and descending transport of amino acids was highest in substantia nigra and midline structures of the mesencephalon and pons including central gray, ventral tegmental area, raphe and ventral tegmental nuclei. These results provide evidence for an energy intake regulatory mechanism situated in the BVMH whose outputs may modulate activity in the substantia nigra and midline brain stem areas.

Animals↗
PubMed1980

Production of amylase(s) by Schwanniomyces castellii and Endomycopsis fibuligera.

Schwanniomyces castellii and Endomycopsis fibuligera Produced extracellular amylase(s) when grown on various carbon sources and at different pH values. Both yeast species showed significant amylase synthesis in the presence of either maltose or soluble starch. On the other substrates tested (glucose, cellobiose, sucrose, trehalose, melezitose, raffinose, ethanol, glycerol) differences were found regarding growth and amylase production. Free glucose in the culture medium apparently inhibited enzyme synthesis. The pH range allowing maximal growth and amylase production was 4.5-6.0 for E. fibuligera and 5.5-7.0 for S. castellii.

Amylases↗
PubMed1980

Maternal plasma prolactin levels in preeclampsia.

Maternal plasma prolactin, estradiol-17 beta, and free estriol levels were estimated in 118 normal pregnancies and in 90 patients with preeclampsia at 35 to 40 weeks' gestation. In the preeclamptic patients, the prolactin values were similar to those of normal pregnancy; the levels were not affected by the severity of disease. At 37 to 38 weeks' gestation the maternal plasma free estriol levels correlated positively with the prolactin levels in preeclampsia (r = .313; P less than .05; N = 64). No correlation was found between the levels of prolactin and estradiol-17 beta or between prolactin and urinary estrogen. Fetal distress was related to decreased plasma estradiol levels, but this was not reflected in the prolactin concentrations. The results of the present study show that the estimation of plasma prolactin level is of no clinical significance in patients with preeclampsia.

Estradiol↗
PubMed1979

Elevated plasma prolactin concentration in cholestasis of pregnancy.

The plasma concentrations of prolactin and estradiol-17 beta were measured by specific radioimmunoassays in 150 women with normal pregnancies and 76 women with cholestasis of pregnancy. At 33 to 34 weeks of gestation plasma prolactin concentrations were 187 +/- 23 ng/ml (mean +/- S.E.M.) for normal pregnancy and 341 +/- 38 ng/ml for cholestasis (p less than 0.001). At 35 to 36 weeks they were 254 +/- 24 and 355 +/- 26 ng/ml (p less than 0.01), and at 37 to 38 weeks 175 +/- 14 and 365 +/- 34 ng/ml (p less than 0.001), respectively. Higher prolactin levels in the cholestasis group were not related to differences in plasma estradiol-17 beta concentrations. No correlation was found between plasma prolactin and serum aminotransferase levels, or between prolactin levels and placental weight. The mechanisms by which plasma prolactin levels become elevated in cholestasis of pregnancy remain to be elucidated.

Cholestasis↗