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Biomedical subjects

P F Barra

Publications and source records attributed to P F Barra.

17 recordsLinked to original sources
PubMed1995

Comparison of body weight, body height and body fatness of Italian children aged 6-12 years with American standards.

World Health Organization has suggested that American standards may be adopted for use in countries where no local reference data are available. Since no locally accepted growth standard is available in Italy, this study investigated if American growth curves for weight, height and triceps skinfold (TSF) provide reliable values for Italian children. Weight, height and TSF were measured in 1273 Italian children (boys: 656, girls: 617) ranging in age from 6 to 12 years and their percentiles were compared with that provided by NCHS for American children. Despite some minor differences, it is shown that American standards can be used safely in Italian children aged from 6 to 12 years.

Anthropometry↗
PubMed1991

Body impedance measurements during dialysis.

Changes in body weight in relation to changes in body impedance were studied in six male and four female patients before and during dialysis. Before dialysis, fat-free mass from skinfolds was 46.5 +/- 6.8 kg, and total body water calculated from bio-electrical impedance was 36.9 +/- 5.2 kg. Body water expressed as a percentage of fat-free mass was calculated to be 80 +/- 4%. Mean weight loss, which was assumed to be only loss of water, was 2.7 +/- 0.7 kg. Total body impedance increased by 80 +/- 16 omega from 495 +/- 39 omega to 575 +/- 47 omega. Weight loss and increase in body impedance were highly correlated (r = -0.91, P less than 0.001). However, based on prediction formulas for total body water from bio-electrical impedance, the observed weight (water) loss should be associated with an increase in impedance of only 39 +/- 11 omega. It is concluded that the impedance value before dialysis is a relatively low value, due to the low specific resistivity of the excess of extra-cellular water in the body before dialysis. As a consequence, prediction formulas for body composition from bio-electrical impedance, developed in normal hydrated subjects, overestimate body composition (total body water, fat-free mass) in subjects with oedema.

Adipose Tissue↗
PubMed1986

Control mechanisms of peripheral enkephalin hydrolysis in mammalian plasma.

The protection of the adrenal-released enkephalins from enzyme hydrolysis by endogenous plasma components was studied in laboratory animals and in man. The results indicate that mechanisms active in protecting leu-enkephalin from hydrolysis are present in the plasma of all species examined. The protection seems to be due to two groups of substances, possibly of peptidic nature. The amount of protection given by these substances seems to be sufficient to play a significant role in controlling the physiological levels of leu-enkephalin released into the bloodstream.

Amino Acids↗
PubMed1982

Neuronal responses to putative neurotransmitters during penicillin epileptogenesis.

An epileptogenic process was induced within the rat frontoparietal cortex by microiontophoretic applications of penicillin. The temporal development of the penicillin-induced activity was divided into (a) a first phase characterized by an increased rate of neuronal firing, (b) a pre-paroxysmal phase wherein neurons began to fire clusters of action potentials and (c) a paroxysmal phase characterized by a discharge of action potential clusters. The excitatory responses to glutamate and to acetylcholine appeared to be enhanced during the first and pre-paroxysmal phases, whereas a loss of the excitatory effectiveness of both glutamate and acetylcholine occurred during the final paroxysmal phase. Forty nine of 69 neurons studied (71%) showed a decreased sensitivity to gamma-aminobutyrate during the first phase of penicillin iontophoresis. However, during this same time, glycine-induced inhibition was not decreased. During the second phase, gamma-aminobutyrate-induced inhibition was even less effective, and glycine started to lose effectiveness. During the third phase, both these inhibitory neurotransmitters failed to affect the neuronal activity. The other 29% of the neurons studied showed a general diminution to the actions of both gamma-aminobutyrate and glycine when penicillin-induced action potential clusters appeared. Our results suggest that penicillin interferes with gamma-aminobutyrate-mediated inhibition in a large proportion of cortical neurons of the rat. Furthermore, these cortical neurons show changes in the responses to both excitatory and inhibitory neurotransmitters that closely parallel the development of penicillin-induced activity.

Action Potentials↗
PubMed1981

[Preliminary considerations on the occurrence of antigens of the HLA system in a group of chronic glomerulonephritis patients].

80 patients affected by Cronic Glomerulonephritis have been typed for HLA-A-B-C locuses, using a standard NIH Microfinphotoxicity Technique. 66 healthy blood donors have been types as controls. A significantly increased frequency of HLA-Bw35 has been reported in the patients group. Further analysis is needed for definite conclusions about linkage between this disease and HLA antigens.

Chronic Disease↗