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Biomedical subjects

A Catania

Publications and source records attributed to A Catania.

At least 163 records · Page 9Linked to original sources
PubMed1976

Inhibitory effect of somatostatin on dibutyryl cyclic AMP-induced insulin and growth hormone release in human subjects.

The effect of somatostatin on the responses of blood glucose, plasma immunoreactive insulin (IRI), growth hormone (GH), and free fatty acids (FFA) to the injection of dibutyryl cyclic AMP (DBC) was studied in six normal volunteers. DBC, when injected alone, induced a rapid increase in blood glucose and plasma IRI levels, while GH concentrations showed a less marked and more delayed increase and plasma FFA showed a clear downtrend. Somatostatin infusion suppressed the GH and IRI release induced by DBC, potentiated its hyperglycemic effect and changed the pattern of FFA. These results suggest that somatostatin inhibits hormone secretion distal to the generation of cyclic AMP.

Adult↗
PubMed1976

to luteinizing.

The effect of luteinizing hormone-releasing hormone (LHRH) on plasma prolactin (PRL) was studied in eight acromegalic patients. After LHRH injection a significant increase in plasma prolactin levels was obtained in three of them. This non specific prolactin response to LHRH represents an additional proof of the well known abnormalities of pituitary hormone response to various stimuli in acromegaly.

Acromegaly↗
PubMed1976

Pituitary hormone responses to hypothalamic releasing hormones in acromegaly.

The pituitary reserve of GH, prolactin, TSH, LH, and FSH has been studied in a group of 13 acromegalic patients with the aim of evaluating the pituitary function and the activity of the disease. Plasma GH, TSH and polactin were determined after thyrotrophin releasing hormone (TRH) administration, plasma gonadotrophins and GH after luteinizing hormone releasing hormone (LH-RH) administration. The plasma TSH response to TRH was generally blunted in the patients treated with pituitary irradiation; however, none of the patients with diminished TSH reserve had signs of hypothyroidism. Six acromegalics showed prolactin basal levels higher than controls; none had galactorrhoea; 4 of them complained of impairment of the gonadal function. The prolactin response to TRH was variable and not related to prolactin basal levels. A subnormal LH reserve after LH-RH stimulation was observed in 5 out of 10 patients; 4 of them had also clinical signs of hypogonadism. A normal FSH response to LH-RH was present in all patients. A non-specific GH response to TRH and/or LH--RH was obtained in about half of the acromegalics studied. The GH responsiveness to TRH and/or LH-RH was not related to the activity of the disease or to a specific derangement of the hypothalamo-pituitary function. A concordant response was observed only between GH and prolactin response to TRH; the highest prolactin responses to TRH were obtained in the GH responsive patients. Each patient showed a constant GH pattern of response on repeated testing. Even after pituitary irradiation the pattern of GH response was unchanged in spite of lowered GH plasma levels.

Acromegaly↗
PubMed1976

Sequelae of dental extraction during quinine-induced thrombocytopenia.

The pathogenesis and treatment of quinine-induced thrombocytopenia is discussed. The case presented involved the sequelae of a dental extraction performed during an episode of acute thrombocytopenia. A complete medical history and knowledge of current medications and their possible side effects are of paramount importance before any patient is treated.

Aged↗
PubMedDate not supplied

Plasma cortisol response to ACTH does not accurately indicate the state of hypothalamic-pituitary-adrenal axis.

The hypothalamic-pituitary-adrenal function was studied in 55 patients with various pituitary disorders. In particular, the consistency between the responses of plasma cortisol to exogenous ACTH and to insulin hypoglycemia was investigated in 5 patients in whom cortisol response to insulin was absent; four of these patients showed a cortisol response to ACTH of variable degree. These 4 patients had surgical or functional hypothalamus-pituitary disconnection and showed a preserved cortisol response to lysine vasopressin. These data demonstrate the unreliability of ACTH test in assessing hypothalamic-pituitary-adrenal function in hypopituitary patients.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Neuropeptide alpha-MSH antagonizes IL-6- and TNF-induced fever.

The pro-opiomelanocortin-derived peptide melanocyte stimulating hormone (alpha-MSH) antagonizes the fever induced by several stimuli including endotoxin, endogenous pyrogen, and certain cytokines. To determine if alpha-MSH can antagonize the pyrogenic action of recombinant IL-6 and TNF directly within the central nervous system, the cytokines were injected with and without alpha-MSH (200 ng) into a lateral cerebral ventricle of rabbits and rectal temperature was monitored continuously. Central administration of both cytokines caused fever. However, when alpha-MSH was injected after cytokine administration, the fevers were markedly reduced. The results are consistent with previous observations on the antipyretic effect of alpha-MSH and they show that the peptide can act within the brain to antagonize pyrogenic actions of specific cytokines believed to be important in CNS mediation of fever.

Animals↗
PubMedDate not supplied

Anti-inflammatory activity of alpha-MSH(11-13) analogs: influences of alteration in stereochemistry.

D-Amino acid substitutions in the anti-inflammatory/antipyretic Ac-alpha-MSH(11-13)-NH2 tripeptide of Ac-alpha-MSH(1-13)-NH2 were made and the altered peptides were injected in mice treated with picryl chloride. Ear swelling, measured 3 and 6 h after application of the irritant, was reduced by IP injections of Ac-alpha-MSH(11-13)-NH2, in confirmation of previous observations. Ac-[D-Lys11]alpha-MSH(11-13)-NH2 effected similar anti-inflammatory activity but Ac-[D-Pro12]alpha-MSH(11-13)-NH2 was inactive. Ac-[D-Val13]alpha-MSH(11-13)-NH2 and Ac-[D-Lys11,D-Val13]alpha-MSH(11-13)-NH2 generally had greater anti-inflammatory activity than the parent tripeptide molecule; the dose-response relations exhibited the bell-shaped characteristics seen previously with MSH peptides. The results indicate that the L-Pro12 is essential for the anti-inflammatory activity of Ac-alpha-MSH(11-13)-NH2 whereas the L-Lys11 is not. D-Val13 substitution increased anti-inflammatory activity approximately four-fold over Ac-alpha-MSH(11-13)-NH2. These results provide new structure-activity relationships of the anti-inflammatory Ac-alpha-MSH(11-13)-NH2 molecule. The data support the developing idea that alpha-MSH and its COOH-terminal fragments modulate host responses, perhaps by antagonizing the actions of cytokines.

Animals↗
PubMedDate not supplied

Central administration of the peptide alpha-MSH inhibits inflammation in the skin.

Inflammation is generally conceptualized in terms of cells, mediators, and events in the periphery, with no consideration of an influence of the central nervous system (CNS). However, the neuroendocrine peptide alpha-melanocyte stimulating hormone (alpha-MSH) is anti-inflammatory when given systemically and this molecule reaches the brain to exert another effect: fever reduction. Tests on mice indicate that alpha-MSH can act solely within the CNS to inhibit inflammation in the skin. This observation indicates that the central nervous system can inhibit peripheral inflammation via action of alpha-MSH molecules and it further strengthens the idea of neural/endocrine modulation of the host responses.

Animals↗
PubMedDate not supplied

Peptide modulation of inflammatory processes within the brain.

It is clear that inflammatory processes contribute to neurodegenerative disease, stroke, closed head injury, encephalitis, and other CNS disorders. These inflammatory processes are marked by local increases in cytokines, in particular tumor necrosis factor-alpha (TNF-alpha). It is important to control such CNS inflammation in order to preserve neural function. The neuroimmunomodulatory peptide alpha-melanocyte-stimulating hormone (alpha-MSH) has been shown to modulate peripheral inflammation by acting on melanocortin receptors in host cells (macrophages, neutrophils) to inhibit production of such proinflammatory agents. Our results indicate that alpha-MSH likewise acts directly within the brain to modulate local inflammation. To determine if microglia are involved in anti-inflammatory responses to alpha-MSH within the brain, murine cells were tested; they produced TNF-alpha and nitric oxide in response to challenge, and production of both was reduced by alpha-MSH. In tests on human astrocytes, both alpha-MSH (1-13) and alpha-MSH (11-13) reduced TNF-alpha. Ischemia/reperfusion in the posterior circulation in dogs causes inflammatory reactions and disturbance of function, estimated from decreases in auditory-evoked potentials. These deficits were reduced by administering alpha-MSH systemically during reperfusion, moreso when the peptide was given during both ischemia and reperfusion. The results indicate that, much as for inflammation in the periphery, alpha-MSH modulates brain inflammatory responses mediated by proinflammatory agents.

Animals↗
PubMedDate not supplied

Inhibition of systemic inflammation by central action of the neuropeptide alpha-melanocyte- stimulating hormone.

The neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH) reduces fever and acute inflammation in the skin when administered centrally. The aim of the present research was to determine whether central alpha-MSH can also reduce signs of systemic inflammation in mice with endotoxemia. Increases in serum tumor necrosis factor-alpha and nitric oxide, induced by intraperitoneal administration of endotoxin, were modulated by central injection of a small concentration of alpha-MSH. Inducible nitric oxide synthase (iNOS) activity and iNOS mRNA in lungs and liver were likewise modulated by central alpha-MSH. Lung myeloperoxidase activity, a marker of neutrophil infiltration, was increased in endotoxemic mice; the increase was significantly less in lungs of mice treated with central alpha-MSH. Intraperitoneal administration of the small dose of alpha-MSH that was effective centrally did not alter any of the markers of inflammation. In experiments using immunoneutralization of central alpha-MSH, we tested the idea that endogenous peptide induced within the brain during systemic inflammation modulates host responses to endotoxic challenge in peripheral tissues. The data showed that proinflammatory agents induced by endotoxin in the circulation, lungs, and liver were significantly greater after blockade of central alpha-MSH. The results suggest that anti-inflammatory influences of neural origin that are triggered by alpha-MSH could be used to treat systemic inflammation.

Animals↗
PubMedDate not supplied

The neuropeptide alpha-melanocyte-stimulating hormone: a key component of neuroimmunomodulation.

Recent research indicates that the proopiomelanocortin derivative alpha-melanocyte stimulating hormone (alpha-MSH) is a significant modulator of host reactions including fever and inflammation. Although the precise mechanism of action is still unknown, cytokine antagonism is believed to be responsible for at least a part of its anti-inflammatory/antipyretic influence: alpha-MSH antagonizes pyrogenic and proinflammatory effects of cytokines such as interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor (TNF), and interferon gamma (IFN gamma). Although it is clear that the peptide can act within the brain to inhibit fever and peripheral inflammation, an anti-inflammatory effect on a peripheral target was evidenced in animals with transection of the spinal cord. Recent data show that alpha-MSH is significant also in human disorders such as AIDS, rheumatoid arthritis, and myocardial infarction. This molecule is believed to be a key factor in neuroimmunomodulation and it may be useful as a therapeutic agent in control of inflammatory reactions.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Binding of anti-inflammatory alpha-melanocyte-stimulating-hormone peptides and proinflammatory cytokines to receptors on melanoma cells.

alpha-Melanocyte-stimulating hormone (alpha-MSH1-13), a peptide derived from proopiomelanocortin, has remarkable anti-inflammatory and antipyretic activities. This peptide and a tripeptide that forms the COOH-terminal portion of the molecule (alpha-MSH11-13; Lys Pro Val) inhibit inflammation when given centrally or peripherally. Because of the similarity in their actions, the tripeptide has been presumed to be the amino acid message sequence underlying the effects of alpha-MSH1-13. To test the possibility that the two peptides occupy the same receptors, competitive binding experiments were performed with B16 mouse melanoma cells that are known to have alpha-MSH1-13 receptors. In these experiments, alpha-MSH11-13 did not inhibit binding of a radiolabelled alpha-MSH1-13 analog. This finding suggests that alpha-MSH1-13 and alpha-MSH11-13 exert their anti-inflammatory/antipyretic/anticytokine effects via stimulation of separate receptors. Because alpha-MSH inhibits the effects of several cytokines including inflammation caused by interleukin (IL)-6 and IL-8, the capacity of these cytokines to compete for alpha-MSH binding sites was tested. There was no evidence that these proinflammatory cytokines bind to alpha-MSH receptors on murine melanoma cells. Although further tests with host cells involved in inflammation are required, the latter result is the first evidence that the mechanism of anticytokine action of alpha-MSH does not depend upon peptide/cytokine competition for binding sites.

Amino Acid Sequence↗
PubMedDate not supplied

The anticytokine neuropeptide alpha-melanocyte-stimulating hormone in synovial fluid of patients with rheumatic diseases: comparisons with other anticytokine molecules.

The aim of this study was to determine if the anticytokine neuropeptide alpha-melanocyte-stimulating hormone (alpha-MSH) occurs, along with interleukin 1 receptor antagonist (IL-1ra) and soluble tumor necrosis factor receptor (sTNFr), in synovial fluid of patients with rheumatoid arthritis (RA), juvenile chronic arthritis (JCA), or osteoarthritis. The data show that alpha-MSH does occur in the synovial fluid and its concentrations are greater in patients with RA than in those with osteoarthritis. Synovial fluid concentrations of IL-1ra and sTNFr were likewise greater in RA. Further, concentrations of alpha-MSH, IL-1-ra, and sTNFr were greater in patients with polyarticular/systemic-onset JCA than in those with pauciarticular disease, that is in patients with greater joint inflammation. Concentrations of alpha-MSH were greater in synovial fluid than in plasma in a substantial proportion of patients, suggesting local production of the peptide; this is the first indication that the anticytokine molecule alpha-MSH is produced within a site of inflammation. Further, it appears that local production of alpha-MSH is induced particularly in those arthritic joints that have more intense inflammatory reactions. This finding, combined with previous evidence of the marked anti-inflammatory activity of alpha-MSH, suggests that the peptide acts locally to modulate proinflammatory influences in rheumatic diseases.

Arthritis, Rheumatoid↗
PubMedDate not supplied

Endotoxin causes release of alpha-melanocyte-stimulating hormone in normal human subjects.

The neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH), a proopiomelanocortin derivative, is a potent modulator of fever, inflammation, and other aspects of the acute-phase response. Alpha-MSH concentrations increase in rabbit plasma after large doses of endotoxin, but it is not known if changes in this potent peptide likewise occur during endotoxemia in humans. The current study performed to assess changes in plasma alpha-MSH during the acute inflammatory response to endotoxin in normal humans. Alpha-MSH was measured in plasma samples obtained over a 5-hour study period in 20 normal human subjects given endotoxin. Plasma adrenocorticotropic hormone (ACTH) and tumor necrosis factor were also measured at the same time points. Endotoxin administration caused fever-related increases in plasma alpha-MSH. Five subjects with a high thermal response to endotoxin (> 2.6 degrees C above baseline) showed a 2- to 4-fold increase in circulating alpha-MSH whereas subjects with low fever (< 2.3 degrees C) did not. Tumor necrosis factor was detected in all subjects after endotoxin, but its peak was significantly less (p < 0.01) in those subjects who had substantial increases in alpha-MSH. Plasma ACTH increased in all subjects given endotoxin, but unlike its 1-13 derivative alpha-MSH, the increases were not commensurate with fever. The data show that challenge with endotoxin causes alpha-MSH release in normal human subjects with high fever. The positive relationship between increases in circulating alpha-MSH and high thermal response together with previous evidence from animal studies suggest that the neuropeptide is an endogenous modulator of host responses.

Adrenocorticotropic Hormone↗