Biomedical subjects

M I Gonzalez

Publications and source records attributed to M I Gonzalez.

24 records · Page 2Linked to original sources

PubMed1994

Interactions between 5-hydroxytryptamine (5-HT) and testosterone in the control of sexual and nonsexual behaviour in male and female rats.

Two 5-hydroxytryptamine2 (5-HT2) agents, ritanserin and 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCl (DOI) (both at 0.25 mg/kg IP), were administered to castrated males bearing graded testosterone implants (empty, 2.5-, 5-, and 10-mm length) and to normal and neonatally androgenized ovariectomized females bearing 10-mm testosterone implants. The results indicate that testosterone stimulates male sexual behaviour and appears to have a dose-related anxiolytic effect, but no effect on other nonsexual activities. 5-HT and testosterone had opposite effects on male sexual behavior, with ritanserin (5-HT antagonist) enhancing activity in both sexes and DOI (5-HT agonist) inhibiting behaviour in males, the latter being testosterone-dependent. Independent of testosterone, ritanserin reduced locomotion and exploration and increased anxiety in males, while DOI increased locomotion and exploration in both sexes. Ritanserin had a gender-specific effect on anxiety which was independent of testosterone, since in castrated males it was anxiogenic whether they bore testosterone implants or not, while in females it was anxiolytic whether the female were neonatally androgenized (250 micrograms/pup testosterone proprionate [TP] on day 1) or not. These results show that 5-HT and testosterone have opposite effects on male sexual behaviour and these may be interrelated. In adulthood, their effects on nonsexual activities are not inversely related and are independent of each other in contrast to the relationship seen in the neonatal period.

Amphetamines↗

PubMed1993

Interaction of oestradiol, alpha-melanotrophin and noradrenaline within the ventromedial nucleus in the control of female sexual behaviour.

A possible inter-relationship between oestrogen, alpha-melanotrophin (alpha MSH) and NA in the ventromedial nucleus (VMN) has been studied in ovariectomised-adrenalectomised rats primed with a low dose of oestradiol benzoate (2 or 5 micrograms OB), which induces receptivity in approximately half the rats. Priming with OB increased NA turnover in the VMN (as assessed by the decline in NA concentration 1 h after 250 mg/kg alpha-methyl tyrosine alpha MT) and also enhanced the release of NA from basal medial hypothalamic fragments in vitro. This occurred whether the rats were receptive or non-receptive. Injection of 20 micrograms/rat alpha MSH, 4 h before autopsy in OB-primed rats, reduced NA turnover in the VMN but only in the receptive animals. alpha MSH had no effect on NA content in the VMN, but prevented the decline normally induced by the alpha MT, indicating an inhibition of release. Application of 1 microgram/ml alpha MSH to incubated hypothalamic fragments enhanced release of NA in the tissue obtained from untreated controls and the OB-non-receptive group, but had no effect on the tissue of the OB-receptive animals. Perhaps NA release had already occurred in vivo in the latter group. alpha MSH (100 ng/side/rat) and NA (20, 200 and 2,000 ng/side/rat) were injected into the VMN of ovariectomised-adrenalectomised rats primed with 1 microgram OB. Both agents stimulated lordosis in non-receptive animals with a peak activity at 60 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Sexual differences in the neonatal serotonin effect on hormone secretion in rats.

A number of authors in the literature have reported facilitatory or inhibitory effects of serotonin (5-HT) on gonadotropin secretion, sexual hormones content or sexual behavior, but little information has been reported about the possible role of serotonin administered during the critical period of sexual differentiation. To test this possibility, we have injected a 5-HT intraventricularly to neonate male and female rats in order to examine the influence during the critical period of this single treatment on the adult sexual hormone content and sexual behavior. Neonatal administration of 5-HT in the brain decreases significantly estradiol content of adult females, without affecting testosterone level in males. Neither male nor female sexual behavior was affected by 5-HT injection on day 1 of life. These data evidence a sexual difference of serotonin administration during the critical period on gonadal hormones secretion in adulthood.

Aging↗

PubMed1985

A randomized study comparing a transparent polyurethane dressing to a dry gauze dressing for peripheral intravenous catheter sites.

We studied rates of peripheral intravenous (IV) catheter tip and insertion site colonization after randomly assigning patients to transparent polyurethane (TP) dressings (N = 316) or dry gauze (DG) dressings (N = 421). The study was conducted during both summer and fall seasons, in a facility which lacked air conditioning. All patients had a teflon plastic catheter inserted, maintained and cultured by a member of the IV therapy team; no antibiotic or antiseptic ointments were used. Colonization rates were higher in the summer than in the fall for both catheter tips (9.0% vs 3.5%, p = 0.005) and sites (21.6% vs 7.0%, p = 0.001). During the summer season, the rate of catheter tip colonization with TP dressings was nearly twice that of DG dressings (12.4% vs 6.8%, p = 0.04). Logistic regression analysis indicated that catheter tip colonization was associated with the summer season (odds ratio = 3.0, 95% CI 1.4-6.2) and TP dressings (odds ratio = 1.8, 95% CI 1.1-3.2), and that site colonization was associated with both summer (odds ratio = 4.0, 95% CI 2.2-7.1) and receipt of antibiotics (odds ratio = 1.9, 95% CI 1.1-3.2). Coagulase-negative staphylococci were isolated from 55.5% of the colonized catheter tips and insertion sites. The data suggest that bacterial colonization of peripheral IV catheters is increased in summer, and that use of TP dressings may increase both tip colonization and cost nearly twofold.

Bacterial Infections↗

PubMedDate not supplied

Regulated expression of galectin-1 after in vitro productive infection with herpes simplex virus type 1: implications for T cell apoptosis.

Apoptosis of cytotoxic T lymphocytes by herpes simplex virus type-1 (HSV-1) has been reported to be a relevant mechanism of viral immune evasion. Galectin-1 (Gal-1), an endogenous lectin involved in T-cell apoptosis, has recently gained considerable attention as a novel mechanism of tumor-immune evasion. Here we investigated whether infection of cells with HSV-1 can modulate the expression of Gal-1. Results show that pro-apoptotic Gal-1, but not Gal-3, is remarkably up-regulated in cell cultures infected with HSV-1. In addition, this protein is secreted to the extracellular milieu, where it contributes to apoptosis of activated T cells in a carbohydrate-dependent manner. Since many viruses have evolved mechanisms to counteract the antiviral response raised by the infected host, our results suggest that HSV-1 may use galectin-1 as a weapon to kill activated T cells and evade specific immune responses.

Animals↗

PubMedDate not supplied

Interaction between clonal plasma cells and the immune system in plasma cell dyscrasias.

The term "monoclonal gammopathy" (MG) includes a group of clonal plasma cell disorders, which show heterogeneous clinical behavior. While multiple myeloma (MM) and plasma cell leukemia (PCL) are incurable malignant diseases, most patients with MG of undetermined significance (MGUS) show an indolent/benign clinical course. Evidence has accumulated which supports the role of the bone marrow microenvironment in MG. Accordingly, the survival, drug-resistance and proliferation of MM cells have been shown to be largely dependent on a supportive microenvironment. Among the different environment-associated parameters, those related to the status/activity of the immune system are particularly relevant. This review focuses on the different ways clonal plasma cells (PC) interact with the immune system in different models of MG, to characterize crucial events in the development and progression of MG. These advances may support the design of novel therapeutic approaches in patients with MG.

Bone Marrow↗