PubMed Health⌕ Search

Biomedical subjects

G Marini

Publications and source records attributed to G Marini.

At least 19 recordsLinked to original sources
PubMed1992

Effect of cholinergic tone on growth hormone-releasing hormone-induced secretion of growth hormone in normal aging.

Aging is associated with an impairment in the GH response to GHRH and to several other stimuli of GH secretion. We evaluated the effect of pyridostigmine (PD) or placebo pretreatment (Protocol A: placebo or 120 mg PD orally at 8 a.m.; Protocol B: placebo or 60 mg PD twice orally at 9 p.m. and 7 a.m.) on GH responsiveness to GHRH (1 micrograms/kg BW bolus i.v. at 9 a.m.) in 15 normal elderly males (65-92 years) and in 14 normal young adults (20-37 years). GH response to GHRH was significantly reduced in elderly subjects compared to young adults (p < 0.05). PD (Protocol A) increased GH release in both elderly and young subjects. In elderly men, PD enhanced GH response to GHRH. The phenomenon was more evident when PD was administered according to Protocol B (p < 0.01). The area under the curve of GH was significantly greater after PD plus GHRH than it was after placebo plus GHRH (p < 0.01). In young adults, PD induced an increase in GH responsiveness to GHRH when administered according to Protocol A (p < 0.05) but not Protocol B. Both GH peak and AUC of GH after PD plus GHRH (Protocols A and B) in elderly subjects were not significantly different from the same parameters found in young subjects after placebo plus GHRH. Our data confirm that pituitary somatotrophin responsiveness to GHRH in man changes with aging. PD restores GH responsiveness to GHRH in elderly subjects. The effect of PD on GH secretion suggests that cholinergic mechanisms may be involved in GH control in normal aging.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Enhancement of tonic and phasic events of rapid eye movement sleep following bilateral ibotenic acid injections into centralis lateralis thalamic nucleus of cats.

The excitotoxin ibotenic acid (1.2-2.6 microliters of 50 micrograms/microliters) was injected bilaterally into the thalamic centralis lateralis nucleus of chronically implanted cats in order to study the effects of tonic excitation followed by destruction of perikarya on the sleep-waking cycle and its electrographic correlates. Ibotenate injections were performed under mild ketamine anaesthesia. Immediately afterwards, the animals showed behavioural arousal accompanied first by ocular nystagmiform movements and then by pontogeniculooccipital waves. By 6-10 h post-injection, the numbers of rapid eye movement sleep episodes, but not their duration, increased compared to the preinjection control period. The injection sites were histologically confirmed using conventional Thionin stains. Additional control was provided by retrograde transport of wheat-germ agglutinin conjugated with horseradish peroxidase. The present results suggest that a population of neurons important for ocular saccades, pontogeniculooccipital waves, and the state of desynchronized sleep is present in the internal medullary lamina, in particular in the centralis lateralis nuclei.

Animals↗
PubMed1992

Innervation of the paralyzed laryngeal muscles by phrenic motoneurons. A quantitative study by light and electron microscopy.

In the cat, inspiratory opening of the paralyzed glottis recovered after unilateral or bilateral reinnervation of the posterior cricoarytenoid (PCA) muscles by phrenic axons. The morphometric analysis of the regenerated recurrent laryngeal nerves (RLNs), showed that proliferation was abundant; 4 months after the nerve anastomosis, more than 500 myelinated axonal branches repopulated the RLNs. The mean diameter of motor axons (3.5 to 5.0 microns) was lower than in normal phrenic and RLN (8 to 10 microns), and the mean internode length was about half that of the normal RLN. Histochemical examination of the PCA muscle revealed that muscle fiber composition (44% type I and 56% type II muscle fiber) was fairly similar to that of normal PCA. The contraction time of the reinnervated muscles was as long as 60 msec at the time of movement recovery, but it shortened to 25 to 30 msec when the reinnervation time increased. These anatomical and functional results support the choice of the phrenic nerve for laryngeal reinnervation.

Adenosine Triphosphatases↗
PubMed1992

The effect of a met-enkephalin analogue on growth hormone, prolactin, gonadotropins, cortisol and thyroid stimulating hormone in healthy elderly men.

The aim of the study was to evaluate the effect of the guanyl derivative of the opioid analogue D-ala2,MePhe4-Met-enkephalin-(o)-ol (G-DAMME) on pituitary secretion in healthy elderly men. Nine healthy elderly men (65-88 years) and 10 young adults (20-30 years) were studied. GH, PRL, gonadotropins, cortisol (to evaluate the effect on ACTH) and TSH were measured after G-DAMME (0.25 mg iv) or placebo administration. In elderly men, the GH response to G-DAMME was reduced or absent, while prompt GH release was found in all young men. G-DAMME lowered LH levels in young men but not in elderly men. No significant variations in FSH levels after G-DAMME and placebo were noted in either group of subjects. A similar and significant rise in PRL and TSH, and a fall in cortisol, after G-DAMME was observed in both elderly and young adults. We have demonstrated that the sensitivity to opioid modulation by G-DAMME on PRL, TSH and cortisol secretion is unchanged with aging. On the other hand, the data indicate that LH and GH responsiveness to G-DAMME change with age.

Adult↗
PubMed1979

[Histochemical demonstration of tetrahydrofolate dehydrogenase in human bone marrow: apparent enzymatic induction after administration of folic acid antagonists].

Folate antagonists interfere to a varying extent with the histochemical demonstration of tetrahydrofolate dehydrogenase. Some aspects of this interaction are investigated in normal hemopoietic cells of patients following antitumor treatment with methotrexate. In this situation the histochemically detectable activity of tetrahydrofolate dehydrogenase exceeds the control levels (apparent enzymatic induction). A protection of the enzyme-metabolite complex from degradation and diffusion might be effective for the changes in reaction intensity.

Bone Marrow↗
PubMed1979

A histochemical study of the binding of 125I-HCG to the rat ovary throughout the estrous cycle.

Changes in the distribution of the in vitro uptake of 125I-HCG by the ovaries of adult rats were examined histochemically throughout the estrous cycle. Only in follicles wider than 500 micrometer, occurring mainly at diestrus and proestrus, could granulosa cells bind the labelled hormone. The labelling increased with follicular size and decreased in intensity from the peripheral granulosa cells inwards. No uptake occurred in the oocytes, in the cells of the cumulus oophorus nor in the granulosa cells of the atretic follicles. The binding capacity of the newly-formed corpora lutea of estrus was less than that of preovulatory follicles. The uptake of 125I-HCG by corpora lutea during the first cycle reached its maximum at diestrus but fell sharply by proestrus. The uptake was patchy in the corpora lutea of the second cycle and not significant in the older ones. The uptake of 125I-HCG by thecae increased with follicular size and was greater in the thecae of atretic follicles than in the thecae of growing follicles of like size. There was a greater uptake in the last formed interstitial tissue than there was in older tissue. At proestrus, the uptake of 125I-HCG was unaffected by the LH surge at 18.00 h but had decreased slightly at 24.00 h. The implications of these data in relation to the regulation of receptor sites, is discussed.

Animals↗
PubMed1979

Carcinoma associated with lipomeningocele: case report.

We report the case of a 41-year-old man with an epidermoid carcinoma that had developed on a meningocele with a fistulous tract that chronically drained cerebrospinal fluid. After a review of the literature, we discuss the cause of this rare occurrence. We think that the recurrent discharge of spinal fluid (never complicated by meningitis) may have caused a chronic irritation of the tissues and then the delayed development of a carcinoma, which is similar to a case found in the literature. In our case there was a "flow" of carcinomatous cells along the fistula, which entered the meningocele, invading the subdural space as far as the peduncle. Our patient, who had a benign lesion (meningocele), came under neurosurgical care only after the lesion had degenerated. The malignant degeneration of such a benign lesion emphasizes the need for surgical treatment as soon as possible.

Adult↗
PubMed1979

In vitro binding of radioiodinated rat follicle-stimulating hormone to the testis of the mallard duck, Anas platyrhynchos l.

The binding of 125I-labelled rat FSH to homogenates and frozen sections of mallard duck testis was investigated. The equilibrium association constant (Ka) in the homogenates (8.5 x 10(9) M-1) was similar to those reported in other avian and mammalian species. Autoradiography suggested that the binding sites for the labelled hormone were localized in the tubular compartment.

Animals↗
PubMed1979

A case of acute myelomonocytic leukaemia associated with therapy: Feulgen-DNA microdensitometric determinations.

A cytochemical study of a case of acute myelomonocytic leukaemia, which arose after radiation therapy and polychemotherapy for Hodgkin's disease, is presented. The distribution of the DNA content of the circulating blood cells appears to be different from the unimodal diploid distribution reported in the literature for acute myelomonocytic leukamias not associated with therapy. This finding seems to strengthen the hypothesis, already put forward by Marinone et al. (1979), that a particular pattern of DNA content distribution could be characteristic of leukaemias linked to chemotherapy and radiotherapy.

Adult↗
PubMed1978

The amyloidosis.

The clinical and pathological features of amyloidosis are examined in the light of a classification based on anatomical models of amyloid distribution: 1) generalised amyloidosis, including primary and secondary sporadic forms, hereditary and familial amyloidosis, and senile amyloidosis; 2) local amyloidosis, including amyloid tumours, neoplasia with amyloid stroma, and other forms. The nature of amyloid is described. Morphological, ultrastructural, biochemical and immunochemical research has shown that: 1) amyloid is a fibrillar protein with a typical EM and X-ray diffraction appearance; 2) two main types of amyloid proteins exist, one related to Ig light chains and found in primary forms and in association with myeloma, the other (called AA proteins) being the main component of secondary forms and certain types of familial amyloidosis; 3) serum proteins structurally related to the AA proteins may be used as amyloid precursors. The cause and mechanisms of amyloid production are becoming clearer. In particular, a relation with the production of Igs has been established. Improved methods for the diagnosis and treatment of the disease will throw more light and the nature of amyloid and its protein precursors.

Age Factors↗
PubMed1978

[Results and prospects of therapy of type IV dyslipidemia with chenic acid].

Administration of 500 mg/day chenodeoxycholic acid for 60 days in a series of 44 patients with type IV dyslipidaemia led to gradual normalisation of triglycerides by the end of the treatment. Falls were greater in subjects with initially higher values, but were independent of age, sex, weight and type of diet. Further falls were obtained by repeating the treatment in some cases when prebetalipoproteins rose again. Decreases were already evident by the 5th day (about 24%) and could be obtained with only 4 mg/Kg/day. The rapid effect of the acid and its specific action on prebetalipoproteins were demonstrated by examination of lipid curves after a glyco-lipid load with and without pretreatment with chenic acid. Encouragement of the shunt of triacylglycerols towards the phosphoglycerides during hepatic synthesis of triglycerides is put forward as the most likely mechanism of action in endogenous hyper-triglyceridaemia. The chemical composition of bile is interfered with, which may explain why cholesterol lithiasis is significantly more common in type IV dyslipidaemia than in other forms and in controls, as shown by statistical analysis.

Adult↗
PubMed1978

The hypotriglyceridemic effect of chenodeoxycholic acid in type IV hyperlipemia.

The effect of chenodeoxycholic acid on the fasting serum triglycerides was studied in 30 patients with type IV hyperlipemia and in 20 patients with primary gout and associated endogenous hypertriglyceridemia, the triglycerides being determined before treatment and at monthly intervals for three months. Chenodeoxycholic acid treatment resulted in a significant lowering of the serum triglycerides in both groups of patients. The drug was well tolerated and there were no undesirable side-effects. Although the mechanism of action is still not known, the drug is thought to reduce triglyceride synthesis in the liver. Chenodeoxycholic acid appears to be electively indicated in type IV hyperlipemia treatment.

Adult↗