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Biomedical subjects

B Marín

Publications and source records attributed to B Marín.

At least 19 recordsLinked to original sources
PubMed2004

Role of apolipoprotein E epsilon 4 allele on chronic allograft nephropathy after renal transplantation.

Lipid abnormalities may contribute to chronic allograft nephropathy (CAN). Apolipoprotein E (ApoE) gene polymorphism regulates lipoprotein metabolism, but little is known about an association between CAN and this polymorphism. The ApoE gene (E3/E4) polymorphism was typed by PCR assay (99 E3/E3, 28 E3/E4, 1 E4/E4) on 128 consecutive renal transplant patients with functioning grafts for more than 3 years (6.7 +/- 2.8 years). Twenty-eight patients with histological CAN were compared with 100 patients who had no clinical evidence of chronic rejection (no proteinuria and sCr < 2.5 mg%). As expected, univariate analysis revealed that patients with CAN experienced a greater acute rejection rate (78% vs 21%; P=.001), a higher serum creatinine (3.6 +/- 1.7 vs 1.4 +/- 0.5 mg%; P=.0001), and an older organ donor (43 +/- 20 vs 29 +/- 13 years; P=.0001). The lipid profiles (total cholesterol and triglycerides levels) were similar in both groups with 60% in each group receiving anti-lipemic drugs. Interestingly, the ApoE epsilon 4 allele was overrepresented in the group with CAN (39% vs 17%, P=.019). Logistic regression analysis showed that the epsilon 4 allele was an independent predictor of CAN (OR: 3.4; CI 95%: 1.07 to 11; P=.040) as were donor age and acute rejection episodes. In conclusion, an interaction between risk factors and genetic factors may determine CAN in this population. This finding may help to target prophylactic interventions in these recipients.

Adult↗
PubMed2004

[Intracerebral haemorrhage by cerebral hyperperfusion after carotid angioplasty in a tandem lesion. A case report].

Intracerebral hemorrhage (ICH) by hyperperfusion after carotid angioplasty has a frequency of 1.2 % - 4.4% in the literature. Until now no case of ICH after carotid angioplasty in a tandem lesion has been reported. We present the case of a patient who suffered an ICH due to the hyperperfusion syndrome, after carotid angioplasty of two stenotic lesions of the left internal carotid artery (ICA) (intracranial and extracranial). He was a 58 year old man who suffered repetitive left carotid TIA despite being treated with antiplatelet therapy. An angiogram showed 76 % extracranial stenosis and 96 % intracranial stenosis of the left ICA as well as 59 % extracranial stenosis of right ICA. Angioplasty with stenting of the two stenosis of the left ICA was performed. After 48 hours of the angioplasty, the patient presented a massive ICH and died a few hours later. ICH by hyperperfusion is an infrequent complication of the carotid angioplasty. The risk factors of the ICH should be evaluated in order to decrease their incidence as well as to maintain an intensive control of the arterial pressure during and after the procedure. This case is the first one published after angioplasty of a tandem lesion. It is possible that the pathophysiologic mechanism involved was an excessively rapid restitution of the normal arterial size.

Angioplasty↗
PubMed2000

[Verification of the eclossion mark on the sagittal otolith of the larvae of Sardinella aurita (Pisces: Clupeidae)].

The study of otolith in larvae is important to determine fish age and growth, essential parameters in the study and management of fisheries resources. In this study, the formation of the hatching mark in Sardinella aurita was verified on ichthyoplankton samples collected off southern Cubagua island, Venezuela, from May 1998 to January 1999. The embryos were kept alive using a culture system until they hatched and daily a group of 10 to 30 larvae were fixed in 95% ethanol. An image analysis system was used to measure morphometric characteristics of larvae and sagittal otoliths. Following are mean values in newly hatched larvae: otolith hatching mark distance from nucleus 4.78 m (I.C. 0.36 m, p 0.05 n = 30), increase width 1.46 m (I.C. 0.17 microm, p 0.05, n = 30) and diameter 14.28 m (IC 1.11 m, p 0.05, n = 30). The mean standard length of larvae at age 0 was 3.31 mm (I.C. 0.08 mm, p 0.05, n = 200). The identification of the hatching mark allows the exact calculation of the number of rings in larvae from the natural environment.

Animals↗
PubMed1999

Prenatal melatonin influences developmental changes of tachykinins in response to estradiol benzoate.

The developmental changes of hypothalamic, pituitary, striatum and pineal gland tachykinin concentrations, as well as the response to estradiol-benzoate (EB) administration, were studied in offspring of control and melatonin (MEL) treated mother rats. Female rats were studied throughout different phases of the sexual development: infantile, prepubertal and pubertal periods, in the four following groups; control-offspring+vehicle; control-offspring+EB; MEL-offspring+vehicle; MEL-offspring+EB. Hypothalamic NKA in control-offspring+ vehicle was significantly increased only at 27 days of age and in control-offspring+EB at 27 days of age and during the infantile period. Hypothalamic SP levels increased similarly in control-offspring+EB during the infantile period but the EB influence was more pronounced with significantly increased concentrations at 32 days of age. Prenatal melatonin treatment produced major alterations in these patterns of postnatal development. In MEL-offspring+EB tachykinins concentrations in the hypothalamus during infantile and prepubertal periods did not increase, however at 37 days of age, they showed significantly higher values than in control-offspring+EB groups. The developmental pattern of pituitary NKA and SP concentrations in both; control-offspring+vehicle and control-offspring+EB groups, showed similar values from the infantile period to puberty, indicating that NKA and SP concentrations remained at similar levels independently of the sexual stage, only at 27 days of age in control-offspring+EB significantly increased values were found as compared to MEL-offspring+EB. Prenatal melatonin did not produce marked modifications, only significantly lower NKA and SP concentrations in MEL-offspring+EB group were observed at 25 days of age in comparison to control-offspring+EB group. Striatal NKA and SP concentrations showed a similar developmental pattern. In control-offspring, EB treatment produced NKA and SP decreased concentrations at the infantile period than in control-offspring+vehicle and significantly increased concentrations during the prepubertal period, then during the pubertal period NKA and SP concentrations decreased in control-group+EB. However, prenatal melatonin treatment reduced the levels of striatal NKA and SP during the prepubertal period after EB treatment and delayed until pubertal period the increase previously observed in control group during the prepubertal period. In MEL-offspring+vehicle group striatal concentrations of both tachykinins remained at low levels from infantile period until pubertal period. Prenatal melatonin and EB did not produce major alterations in SP pineal concentrations throughout sexual development. Plasma estradiol concentrations were significantly higher in the groups that received EB treatment than in those that received vehicle during prepubertal and juvenile periods in control-offspring+EB group and during the pubertal period in MEL-offspring+EB group. These data indicate that prenatal MEL treatment may influence NKA and SP developmental pattern from the infantile period until adulthood in the female rat.

Animals↗
PubMed1999

Lemierre's syndrome (necrobacillosis).

Lemierre's syndrome or postanginal septicaemia (necrobacillosis) is caused by an acute oropharyngeal infection with secondary septic thrombophlebitis of the internal jugular vein and frequent metastatic infections. Fusobacterium necrophorum is the most common pathogen isolated from the patients. The interval between the oropharyngeal infection and the onset of the septicaemia is usually short. The most common sites of septic embolisms are the lungs and joints, and other locations can be affected. A high degree of clinical suspicion is needed to diagnose the syndrome. Computed tomography of the neck with contrast is the most useful study to detect internal jugular vein thrombosis. Treatment includes intravenous antibiotic therapy and drainage of septic foci. The role of anticoagulation is controversial. Ligation or excision of the internal jugular vein may be needed in some cases.

Fusobacterium Infections↗
PubMed1999

Effect of exogenous melatonin on neuroendocrine-reproductive function of middle-aged female rats.

The possible role of melatonin in the regulation of the reproductive system of female rats during ageing was investigated in middle-aged female rats showing irregular duration of the oestrous cycle (n = 30). Blood samples were obtained by jugular venepuncture during the oestrous cycle in control rats. After this experiment was completed, the female rats were treated with melatonin for 2 months and blood samples were obtained at different stages of the oestrous cycle. Plasma LH, FSH and prolactin concentrations were significantly increased in the afternoon of the day of pro-oestrus after melatonin treatment compared with control rats. Moreover, FSH concentrations too were significantly increased on the morning of pro-oestrus and oestrus in melatonin treated rats compared with control rats. Similarly, oestradiol concentrations were significantly higher on the morning of pro-oestrus in melatonin treated rats compared with controls. Another group of rats showing irregular duration of the oestrous cycle was used to study the possible effect of melatonin treatment on the timing of pro-oestrous surges of LH and FSH. The results showed that LH and FSH peak values occurred at 5 h after melatonin treatment. Pituitary responsiveness to LHRH in a 90 min test was also studied in middle-aged rats showing irregular duration of the oestrous cycle that had been injected for 1 month with either melatonin or saline. Prolactin response was unaffected by exogenous melatonin, but a stimulatory effect of melatonin on LH and FSH pituitary responsiveness to LHRH was observed. The results indicate an improved function of the neuroendocrine-reproductive axis in middle-aged rats after melatonin treatment.

Aging↗
PubMed1997

Plasma levels of beta-endorphin during the menstrual cycle.

During recent years, many research teams have suggested a possible role of endogenous opiates in the control of the menstrual cycle. The level of immunoreactive beta-endorphin was measured on different days during the ovulatory cycle of 131 healthy volunteers. The levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), 17 beta-estradiol and progesterone were also measured. The graphic representation of opiate levels during the female menstrual cycle, where day O is the day of ovulation, shows that plasmatic beta-endorphin levels are not stable throughout. The levels increase progressively during the follicular phase, reaching a maximum (mean 139.49 pg/ml, SD 42.23 pg/ml, 95% confidence interval 121.22-157.75 pg/ml) 4 days before ovulation. During the periovulatory period (days-3 to +3) levels of beta-endorphin are very stable (mean day 0, 27.8 pg/ml, SD 6.36 pg/ml, 95% confidence interval 19.29-27.83 pg/ml) and low (p < 0.05), followed by a renewed increase during the luteal phase (mean day + 5, 87.86 pg/ml, SD 36.49 pg/ml) where a maximum level (mean 102.78 pg/ml, SD 30.35 pg/ml) is reached 24 h before the next menses. The beta-endorphin level has a negative correlation with the LH level (r = -0.50, p < 0.001) on the preovulatory days, and during the luteal phase a positive linear correlation (r = 0.47, p < 0.001) is found with the progesterone level. It seems that beta-endorphin levels in the plasma are influenced by the ovarian steroids. However, the influence of the plasmatic opiate on the gonadotropins is currently under discussion.

Adolescent↗
PubMed1993

Melatonin and gonadotropin hormones in pubertal sportsgirls.

In order to determine the influence of physical training on menstrual disturbances in sportsgirls, the levels of luteinizing hormone (LH), follicle stimulating hormone (FSH) and melatonin have been studied in young athletes of track and field speciality using the Cooper test. Basal hormone levels and anthropometric data were also studied in age matched control girls. No significant differences in LH, FSH and melatonin hormone concentrations were observed between the PRE and POST Cooper test. However, significantly lower basal levels of LH were found in the early follicular phase or luteal phase of sportsgirls when contrasted with the control girls. No differences in FSH levels were observed in the early follicular phase of sportsgirls but higher FSH levels were found in the luteal phase. Daytime melatonin levels of sportsgirls were significantly higher than those in control girls. Age and anthropometric parameters studied showed no differences in height, weight, tricipital skinfold and percentage of body fat, but abdominal and subescapular skinfold measures were greater in control girls than in sportsgirls. It appears that continuous physical training can produce alterations in antireproductive hormone secretion such as melatonin, which can play an inhibitory role on the menstrual cycle hormone patterns in sportsgirls.

Adolescent↗
PubMed1991

Attenuation of insulin-induced drinking by beta-adrenoceptor antagonists.

Insulin-induced drinking (IID) in male Wistar rats, evoked by administering 5 U/kg of crystalline porcine insulin i.p., was significantly decreased by propranolol (0.1 and 0.5 mg/kg s.c.) after 1 and 2 h. The blood glucose of rats treated with a much higher dose of propranolol (10 mg/kg body weight) and insulin did not differ from that of rats treated solely with insulin after 30 and 120 min. Atenolol (0.5 mg/kg s.c.) caused a reduction in IID after 1 and 2h. Butoxamine (1 mg/kg s.c.) also reduced IID after 1 and 2h, and at 0.5 mg/kg after 1h. The alpha-blocker, phenoxybenzamine (10 mg/kg s.c.), had the opposite effect, stimulating IID after 2h. There is no direct evidence that insulin activated the sympathetic system at the doses used in these experiments. Nevertheless, the results reported here seem to be compatible with the involvement of the sympathetic system in IID, possible through the renin-angiotensin system.

Animals↗
PubMed1991

Psychological aspects of insulin-induced thirst.

Fifteen normal volunteers received one insulin injection or saline in two nonconsecutive days. At 0', 30', 60' and 90' water intake was measured. Simultaneously subjective thirst and hunger were recorded by running a set of psychological tests. Water intake was higher after insulin than saline at 60' and 90'. Insulin increases thirst sensation even before the sensation of hunger.

Adult↗
PubMed1991

Melatonin administration during pregnancy retards sexual maturation of female offspring in the rat.

The influence of pineal gland function and of melatonin during pregnancy upon sexual maturation of female offspring in rats was examined. The following groups of Wistar rats were studied: (A) control, (B) melatonin treated (250 micrograms/100 g.b.w. per day) throughout pregnancy, and (c) pinealectomized (pin-x). Melatonin was injected subcutaneously 2 hr before lights off. All groups were housed in 12-hr L:12-hr D. The female offspring were observed until the onset of puberty, and blood samples were collected 5.5 hr after lights off under red light for melatonin and LH determinations by RIA. Ovary, pineal, and pituitary gland as well as body weights were recorded. The offspring of melatonin-treated rats showed later vaginal opening than did those of the other two groups (P less than 0.05 vs. control and P less than 0.01 vs. pin-x offspring), which was accompanied by a lower LH concentration, 0.42 + 0.05 ng LH/ml, showing statistically significant differences with the control levels [1.00 + 0.22 ng LH/ml (P less than 0.05)] and with the pin-x group [1.16 + 0.22 ng LH/ml (P less than 0.05)]. The percentage of rats in proestrus was higher in the offspring of pin-x rats (78.6%; P less than 0.01) compared to control offspring (30%) and offspring of melatonin-treated rats (11.8%). The concentrations of melatonin, 5.5 hr after darkness, were not significantly different among groups. No differences were observed in the body, ovarian, and pineal weights of the studied offspring. The pituitary weight was significantly lower (P less than 0.05) in the offspring of pin-x rats than in the other two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Effect of insulin administration on water drinking in children.

The effect of insulin administration on water intake, was studied in children submitted to standard protocols for stimulation of secretion of hypophyseal hormones by i.v. treatment with several different drugs: insulin, insulin plus TRH and LH-RH; and propranolol, clonidine or LH-RH. Drinking was measured from 0 to 90 min after drug administration; from blood samples taken at 60 min for hypophyseal hormones analysis, microhaematocrit values were measured, as well as plasma renin activity (PRA) and glycaemia. Water intake was significantly higher in both groups of patients receiving insulin than in the control group (no insulin). Haematocrit values did not change after 60 min. There was a significant correlation of glycaemia of individuals from all three groups and water intake at 60 min. PRA was significantly higher in insulin treated individuals.

Adolescent↗
PubMed1989

[Gastric acid secretion plays a role in food and water ingestion in mice].

The influence of blockade of the SAG on food and water intake was studied in the mouse. Proglumide (a gastrin receptor antagonist), the combination of proglumide plus cimetidine (inhibitor of the H2 histamine receptors), proglumide plus vagotomy and the simultaneous action of proglumide plus cimetidine plus vagotomy were used in order to get total inhibition of the gastric acid secretion. Statistical analysis shows that food intake experiences a significant increase by the action of proglumide, proglumide plus cimetidine, proglumide plus vagotomy and proglumide plus cimetidine plus vagotomy in comparison to the control group. However, water intake was significantly lower in proglumide plus cimetidine and proglumide plus vagotomy animals with respect to the other groups studied. In addition, proglumide plus cimetidine plus vagotomy increased significantly water intake in relation to the other groups studied. No changes were found in the body weight of the groups studied. We conclude that SAG plays a role in food and water intake in the mouse and both behaviors are interdependent processes.

Animals↗
PubMed1988

Modifications of the sexual activity in male rats following administration of antiserotoninergic drugs.

The influence of cyproheptadine (CPH), methysergide and 5-hydroxytryptamine (5-HT) was studied on male sexual activity. Wistar rats from a colony of the Department were used. Measures of sexual parameters (number of ejaculations, initial latency, ejaculation latency, refractory period and neuromotor activity) indicate that cyproheptadine and methysergide facilitate male sexual activity. However, 5-HT inhibits male sexual reflex. Our experimental results suggest that the serotoninergic system exerts an inhibitory role on the sexual parameters which comprise the copulatory model of the male rat and also demonstrate that cyproheptadine facilitates sexual behavior of the male rat.

Animals↗