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Biomedical subjects

P Federico

Publications and source records attributed to P Federico.

At least 37 records · Page 2Linked to original sources
PubMed1989

Single-unit activity in the bed nucleus of the stria terminalis during fever.

Arginine vasopressin, released from nerve terminals in the septal region, probably exerts endogenous antipyretic activity. A major source of vasopressin to this area is the bed nucleus of the stria terminalis (BST). In order to characterize electrophysiologically the BST-septal pathway and its potential role in the control of fever, single-unit, extracellular recordings were made from neurons in the BST of anesthetized rats. Afferent and efferent connections were identified by electrical stimulation of the medial amygdaloid nucleus and the ventral septal area (VSA). BST neurons received both inhibitory and excitatory synaptic input from the amygdala and VSA. Efferents to the VSA were identified by stimulus-evoked antidromic spike invasion. Some BST neurons were responsive to peripheral skin temperature (thermoresponsive). The activity of putative vasopressin neurons was studied during prostaglandin E1-induced fever. Although a majority of BST units was unaffected by fever, a proportion of the cells examined increased their firing rates in accordance with reported release of vasopressin in the VSA during fever.

Action Potentials↗
PubMed1989

Effects of benfluorex in obese patients with metabolic disorders.

Fifty obese (BMI = 40.1 +/- 1.5) subjects (21 men and 21 women; average age 38.6 +/- 3.8 years) were prescribed a 600 cal/day diet (carbohydrates 30 g, proteins 60 g, lipids 10 g). Thirty patients were also given benfluorex (three tablets/day) for six months (Group A), whereas the other 20 patients (Group B) were treated with the dietary measures only. Apart from grade II and III obesity, several patients suffered from dyslipidaemia (Group A: n = 10; Group B: n = 7), non-insulin-dependent diabetes mellitus (NIDDM) (Group A: n = 4; Group B: n = 3) or IGT (Group A: n = 8; Group B: n = 6). The usual blood and biochemical tests and clinical examinations were carried out on Days 0, 90 and 180, together with the OGTT and glucagon test to determine blood glucose levels, IRI and CPR. There was no statistical difference between the weight loss of Group A and that of Group B. In Group A there was a statistically significant reduction (p less than 0.001) in total cholesterol, triglycerides, total/HDL-cholesterol and beta/alpha-lipoproteins and a significant increase in HDL-cholesterol and alpha-lipoproteins (p less than 0.001), whereas in Group B only a significant reduction in triglycerides (p less than 0.001) was observed. In NIDDM patients treated with benfluorex, normalisation of basal blood glucose levels was accompanied by an improvement in the OGTT blood glucose curve which was statistically significant relative to Group B. Benfluorex was well tolerated by all patients and no adverse event was reported.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗
PubMed1988

Monoclonal antibodies to bovine parathyroid hormone: production and characterization.

1. This paper describes the production and characterization of monoclonal antibodies against bovine parathyroid hormone (bPTH)-(1-84). 2. Spleen cells from A/J mice successfully immunized with bPTH-(1-84) were fused with SP2/O myeloma cells using PEG 4000 as fusogen. The screening method employed microtiter plates coated with sheep antimouse IgG and the presence of specific monoclonal antibodies was demonstrated by the binding of 125I-bPTH-(1-84). 3. A detailed study of the specificity of the three viable monoclonals with highest affinity showed that two (6FH6 and 6CD4) were amino-terminal specific and the other (5BG9) carboxyl-terminal specific. The two amino-terminal monoclonal antibodies appear to recognize the same antigenic site. 4. The monoclonal antibodies produced are potentially useful reagents for the development of new methods for the measurement of PTH in biological fluids, studies on the interaction of PTH with its receptor, as well as localization of PTH producing cells.

Animals↗
PubMed1987

Characterization of a high-affinity antiserum specific for the amino-terminal sequence of human parathyroid hormone.

1. The present paper describes a detailed study of the specificity of high-affinity antibodies obtained from the yolk of eggs laid by a chicken successfully immunized with synthetic human parathyroid hormone (hPTH)-(1-34). 2. Using 125I-labelled bovine parathyroid hormone (bPTH)-(1-84) purified by high performance liquid chromatography (HPLC) as tracer, and hPTH-(1-34) as reference, we found superimposable curves with hPTH-(13-34), bPTH-(13-34) and bPTH-(1-34); the [Asp-76]hPTH-(1-84) peptide showed a molar percent cross-reactivity (calculated at 50% B/BO) of 73% and the bovine sequence 1-84 of 15%. 3. Studying amidated [Tyr-34] bovine PTH fragments we found the highest cross-reactivity with the peptide 7-34 (33%) followed by 20-34 (1.7%) and 25-34 (0.4%). The bovine sequence 1-25 showed a low reactivity (0.7%) and the 1-12 sequence none at all. Rat parathyroid hormone (rPTH)-(1-34) showed low cross-reactivity (3.1%), the same occurring with peptide [Tyr-34, Norleu-8,18] bPTH-(1-34) (1.5%). 4. The data suggest that the antibodies studied recognize epitopes in or near amino acids 18 to 25 of the sequence of the hPTH molecule. This region of the molecule is coincident with the antigenic determinant predicted by the analysis of the hydrophilicity plot of the hPTH-(1-34) peptide.

Amino Acid Sequence↗
PubMed1986

Inhibition of the in vivo parathyroid hormone-mediated calcemic response in rats by a synthetic hormone antagonist.

The parathyroid hormone (PTH) analog, [Tyr34]bovine PTH-(7-34)-amide, can inhibit the PTH-mediated elevation of plasma calcium in thyroparathyroidectomized rats in vivo. The analog is devoid of PTH-like agonist activity in this system. Repeated doses of analog inhibit the animal's calcemic response to PTH. The elevation in serum calcium levels mediated by PTH in this assay reflects PTH action (calcium mobilization) on bone. Earlier studies demonstrated antagonist properties of the analog in a renal-based assay; PTH-stimulated increases in urinary phosphate and cyclic AMP excretion were completely inhibited by the synthetic analog. Along with previous studies, this report indicates that [Tyr34]bovine PTH-(7-34)-amide is an effective in vivo antagonist for several major parameters of PTH action in both kidney and bone.

Animals↗
PubMed1980

[Effect of sex on annual variations in plasma LH and FSH levels in prepubertal subjects].

We studied, from 1977 to 1979, 61 females and 72 males (aged 6 to 10 years) in order to demonstrate the occurrence of FSH and LH circannual variations. The data were fitted a cosine function by least square method in order to describe any rhythm and to estimate its parameters:mesor, amplitude, acrophase. Our data suggest that in prepubertal age the behaviour of FSH secretion is different in two sexes, but without circannual rhythm. LH instead shows a statistically significant circannual rhythm in both groups, without differences in mean levels between the two sexes.

Female↗
PubMed1980

[Effect of sex on annual variations in GH response to insulin hypoglycemia in prepuberal subjects of small stature].

86 males and 66 females, aged 6 to 10 years, affected by short stature (SDs -2 according to Tanner), were investigated from 1977 to 1979 in order to evidence any circannual rhythm in the GH response to insulin test. The patients were hospitalized one week before the study starting and they observed the following life schedule:nocturnal rest from 2200 to 0600, meals at 0800, 1300, 1800. The insulin test (0,1 UI/Kg body weight) were administered at 0800. Plasma samples were taken before and after 20, 40, 60, 90 minutes. The single basal data and the peak were fitted a cosine function by least square method in order to describe amy rhythm and to estimate its parameters:mesor, amplitude, acrophase. A significative circannual rhythm in the GH response to insulin is present in the female subjects, with acrophase in December (-354.85 degrees +/- 21.93). Our study suggest that the sex may influence the circannual response of GH to insulin stimulus from prepubertal age.

Body Height↗
PubMed1979

[Effect of pretreatment with metoclopramide on plasma prolactin response to methergoline].

The Authors examined 20 voluntary women without endocrine diseases. The women took 4 mg of metergoline orally and 30-60-90-120-180-240 minutes after the medicament was given the serum prolactin levels were tested. After 3 weeks, 14 among 20 subjects repeated the test assuming during the 3 days before 50 mg of metoclopramide orally once a day. The Authors found a remarkable decline of prolactin serum levels after metergoline administration in all subjects. After metoclopramide administration prolactin serum levels increased meaningly. Metergoline administration gave again considerable fall of prolactin serum levels in the 14 subjects. From the data the Authors affirm that metergoline inhibits prolactin secretion with an antiserotonine action

Adult↗
PubMed1976

Thyrotropin releasing hormone: development of inactivation system during maturation of the rat.

Whereas thyrotropin releasing hormone is rapidly and extensively degraded by plasma of adult rats, no appreciable loss of biological or immunological activity is caused by plasma from rats 4 or 16 days old. The plasma of neonatal rats does not appear to contain an inhibitor of thyrotropin releasing hormone peptidase or a peptidase with altered substrate affinity. The development of an active peptidase in rat plasma suggests a physiological role for inactivation of thyrotropin releasing hormone.

Age Factors↗
PubMed1976

Pituitary-thyroid axis in neonatal and adult rats: comparison of the sexes.

Systematic comparisons have been made of the development of the pituitary-thyroid axes of male and female rats, by measuring plasma thyrotropin (TSH) and thyroxine (T4) concentrations in neonates and adults. Observations were made in untreated groups as well as in rats treated with various regimens of exogenous T4, thyrotropin-releasing hormone, or TSH. All hormone determinations were by radioimmunoassay (RIA). Salient findings include the following: 1) In early neonatal life, untreated rats showed no significant sex difference in the plasma concentrations of either TSH or T4. 2) In adulthood, the plasma TSH of untreated males attained levels strikingly higher than those of neonates-the differences averaged 5-fold more. For females, the increase in plasma TSH during development was less marked, averaging slightly less than 2-fold more. Thus, untreated adults exhibited a clear sex difference in circulating TSH concentrations; the male TSH levels averaged 2.8-fold higher than those of females. 3) Plasma T4 concentrations also increased markedly during development. For both sexes, adult T4 levels were approximately 3-fold greater than the T4 levels in early neonatal life. Among untreated adults, the female T4 concentrations averaged 28% greater than those of males. 4) Plasma TSH and T4 concentrations exhibited only minor fluctuations, of borderline statistical significance, during the female estrous cycle. 5) A significant reduction in responsiveness to exogenous TRH was observed in adult male rats which had been treated with high doses of T4 in neonatal life, although the effect was not completely consistent. No significant reduction was observed in females which received the same treatment. We have concluded that major changes occur in the circulating hormone levels of the pituitary-thyroid axis of the rat between birth and adulthood, and that such changes are not identical for the two sexes.

Age Factors↗