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Biomedical subjects

F Rodriguez

Publications and source records attributed to F Rodriguez.

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

Effects of chronic icv infusion of vasopressin on sleep-waking cycle of rats.

The effect of arginine vasopressin (AVP) on the duration and the relative proportion of sleeping and wakeful periods has been investigated. Vigilance states were determined by visual scoring of polygraphic recordings from unrestrained rats. Animals were implanted with a cannula into the third ventricle through which AVP or related drugs, dissolved in artificial cerebrospinal fluid, were infused at a constant rate by an osmotic pump. Polygraphic data were collected 24 h/day from day 4 to day 9. Recordings were continued for 3 additional days during AVP recovery. AVP infusions significantly increased the amount of time spent in waking compared with control or recovery periods (12%). This effect was mimicked by an AVP agonist (2-phenylalanine, 8-ornithine oxytocin). Oxytocin, a peptide structurally close to AVP, induced a mild change in waking time. The infusion of an AVP antagonist, 1-desaminopenicillamine-2-(O-methyl)tyrosine-arginine vasopressin (dPTyr(Me)AVP), or of anti-AVP antibodies significantly decreased duration of waking. The infusion of antioxytocin antibodies did not modify the duration of waking. The effects of structural analogues of AVP relatively specific for each type of peripheral AVP receptor indicated the participation of a V1-like AVP receptor in the action of AVP on waking time. During infusion of anti-AVP antibodies and dPTyr(Me)AVP and during the first days of recovery from AVP infusion, the ultradian rhythmic distribution of sleep and wakefulness was still present, but the amplitude of the circadian rhythm was reduced.

Animals↗
PubMed1988

Dose-response effect of sublingual captopril in hypertensive crises.

Forty-one patients, presenting in the Emergency Service of the Hospital General y Clinico, Tenerife, with symptoms of hypertensive crisis and supine diastolic blood pressure (DBP) greater than 120 mm Hg, were studied. They received 12.5 mg of sublingual captopril and 30 minutes later, if diastolic blood pressure (DBP) was not 100 mm Hg or less, the same dose was repeated by the same route. Supine systolic blood pressure (SBP), DBP and heart rate (HR) were monitored at 0, 5, 10, 15, 30, 45, 60, and 120 minutes after each administration of captopril. In 27 patients (66%) had a satisfactory response (DBP less than or equal to 100 mm Hg), after a single dose, less than 30 minutes after administration, which persisted at 120 minutes. In 14, a second administration was necessary after 30 minutes, and a satisfactory response to the second dose, defined again as DBP reaching values of 100 mm Hg or less, was achieved in 12 of them (29% of the total group). In two patients (5% of total) no full response was obtained. The observed pattern of response suggests that a sublingual dose of 25 mg of captopril is the minimum effective dose, but it is also possible that administration of 12.5 mg of sublingual captopril at 10 to 15 minute intervals, perhaps up to a maximum dose of 37.5 mg, might be considered as an alternative treatment in hypertensive crises.

Administration, Sublingual↗
PubMed1988

Role of central oxytocin in the control of the milk ejection reflex.

The neuropeptide oxytocin, synthetized by magnocellular neurons in the hypothalamus, is well known for its peripheral action after it is released into the bloodstream from axons in the neurohypophysis. Less familiar is the notion that it is also released centrally to control the activity of oxytocinergic neurons themselves. When injected into the third ventricle of lactating rats during suckling, oxytocin increases the basal firing rate of oxytocinergic neurons as well as their activity at the time of each reflex milk ejection. On the other hand, centrally administered oxytocin engenders the neuronal-glial and synaptic plasticity characteristic of the oxytocin system when it is physiologically activated. From numerous in vivo and in vitro observations, it appears that central oxytocin is released in the hypothalamic nuclei themselves. For example, the use of push-pull cannulae inserted into one supraoptic nucleus of suckled rats shows that oxytocin is released inside the nucleus specifically during milk ejection. Moreover, ultrastructural immunocytochemistry reveals synaptic terminals in the supraoptic nucleus where both the pre- and postsynaptic elements are oxytocinergic. Nevertheless, the mechanism of the central release of the neuropeptide has still to be determined, especially in view of electrophysiological observations indicating that the release process in the hypothalamus is different from that within the neurohypophysis.

Animals↗
PubMed1988

[Emboligenic calcification of posterointernal chordae of the mitral valve. Apropos of a surgically treated case].

We report the case of a 74-year old man who experienced two transient cerebral ischaemic accidents at 24 days' interval, showing that the isolated calcifications on chordae of the mitral valve posterior leaflet responsible for these accidents were exceptionally malformed. Two-dimensional echocardiography was the key examination, as it revealed a left intraventricular mass beneath the smaller mitral valve leaflet. Having excluded other cardiac causes of cerebral ischaemic accident, and faced with the recurrent character of these accidents, we decided to operate. Surgery confirmed the diagnosis. It consisted of resection of the calcified and ulcerated mass, combined with repair of the smaller mitral valve leaflet. Isolated calcifications of the mitral valve chordae are an exceptional cause of embolic accidents of cardiac origin.

Aged↗
PubMed1988

[Comparative study of two methods of determining plasma and salivary theophylline].

A new method for theophylline assay (Aris method), uses an immuno enzyme assay on a solid-phase (strips). We compared it to a HPLC method for 33 plasma samples and 85 saliva samples in children and adults. The correlation-coefficient between the two methods is highly significant (r = 0.976 for plasma samples and r = 0.99 for saliva samples) although we found a significant difference: the average difference is 0.789 microgram/ml for plasmatic levels and 0.55 microgram/ml for saliva levels. The values are rather low and remain widely satisfactory for posology adaptations. The reproducibility of the Aris method is similar to the HPLC method. Its sensitivity is quite satisfactory and can be improved. Yet the good correlations we obtained for plasma as well as for saliva, the rapidity, simplicity, specificity and low cost of this new technique should make the theophylline estimation easier in hospitals and laboratories.

Chromatography, Liquid↗
PubMed1987

In vitro susceptibility of Mycobacterium avium to a new macrolide (RU-28965).

The in vitro susceptibility of Mycobacterium avium to RU-28965 alone and in combination with rifampin, isoniazid, and sulfametoxipiridazine was studied by the agar dilution method. The synergistic effect of the RU-28965 with rifampin has been demonstrated. At a concentration of 16 micrograms/ml or lower of RU-28965, 100% of M. avium strains were inhibited. If 2 micrograms/ml of rifampin is added the MIC of RU-28965 is lowered to 0.25 microgram/ml.

Anti-Bacterial Agents↗
PubMed1987

Plafibride treatment and serum lipids in hyperlipoproteinemias.

A study was made of 26 patients suffering from primary hyperlipoproteinemia; 8 belonging to familial hypercholesterolemia (phenotype IIa), 9 to familial combined hyperlipidemia (phenotype IIb, 9 to familial hypertriglyceridemia (phenotype IV). During treatment, which was continued for two years, all patients received a diet consisting of 45% carbohydrates, 33% fats and 22% protein. They were given 400 mg (TID) of Plafibride after breakfast, lunch and dinner. In the three phenotypes studied, significant decreases in cholesterol, triglycerides, glucose, insulin and lecithin were observed, while there was an increase in HDL cholesterol, free fatty acids and lysolecithin. Tolerance to the drug was good, and a study of different serum enzymes revealed no undesirable collateral effects.

Adolescent↗
PubMed1987

[Evaluation of perfusion technics of the magnocellular nucleus of the hypothalamus in vitro and in vivo].

In suckled rats, OT necessary for the occurrence of the neurosecretory bursts on OT cells, is probably released inside the magnocellular nuclei. In order to demonstrate this in vivo release and to precise the mechanism involved, perifusions were realized in vivo on lactating rats and in vitro with isolated magnocellular nuclei. In vivo, the push-pull perifusion of a single supraoptic nucleus (SON) was realized simultaneously with the recording of the electrical activity of OT cells in the contralateral nucleus. This would allow to determine the possible relationships between the amount of OT released in the SON and the electrical activity of OT cells (bursting activation during suckling or continuous activation during an hyperosmotic stimulation). Results obtained showed 1) that OT was released in vivo inside the SON, 2) that this release was specifically increased during the milk ejection reflex and 3) that this increase was only detectable inside the SON. However, this technique did not permit to determine either the mechanism of OT release or the neuron elements (perikaryon, dendrites, axon collaterals) responsible for this release. That is for why, in vitro perifusions were undertaken with isolated magnocellular nuclei. The first stage was to determine the stimulus able to induce a reproducible increase of OT release. Among the chemical stimuli (neurotransmitters, K+) only K+ at a 56 mM concentration increased OT release by SON but this increase was small and non significant. Repetitive electrical stimulations with short pulses (0.2 to 5 msec) were ineffective even if the pulse intensity was raised up to 10 mA and the frequency up to 80 Hz.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

In vitro susceptibility of Mycobacterium fortuitum, Mycobacterium chelonae and Mycobacterium avium against some quinolones.

The in vitro susceptibility of Mycobacterium fortuitum, Mycobacterium chelonae and Mycobacterium avium to ciprofloxacin, norfloxacin and ofloxacin was studied by the agar dilution method. All strains of Mycobacterium fortuitum were inhibited by 2 mg/ml or less of these antimicrobial agents. Concentrations higher than achievable blood levels were necessary to inhibit Mycobacterium chelonae and Mycobacterium avium.

Anti-Bacterial Agents↗
PubMed1986

Septal release of vasopressin in response to osmotic, hypovolemic and electrical stimulation in rats.

The central release of vasopressin was studied in anesthetized rats using push-pull perfusions and radioimmunoassay of the hormone. A basal release was observed in the lateral septum and in the lateral ventricle, whereas no vasopressin was detected in the perfusates from the caudate nucleus. Under osmotic stimulation, vasopressin release increased up to 12 and 60 times basal levels following i.p. injections of 5 ml and 10 ml/kg b.wt. of 2 M NaCl, respectively. This increase was blocked by using a calcium-free perfusion medium containing 0.1 mM EGTA. In the lateral ventricle, osmotic stimulation (5 ml/kg of 2 M NaCl i.p.) had the same effect as in the septum. In the caudate nucleus, no release was observed. Hemorrhage also increased the septal release of vasopressin in 5 out of 6 animals tested. Electrical stimulation of the pituitary stalk and of the supraoptic nucleus was used to evoke the release of vasopressin into the bloodstream. Septal release slightly decreased during pituitary stalk stimulation, whereas it did increase during stimulation of the supraoptic region. Our results show that systemic stimuli for vasopressin release evoke both a peripheral and a septal release of the hormone. The dissociation of the effects of electrical stimulation of the pituitary stalk and of the supraoptic nucleus suggests, however, that the vasopressinergic neurones responsible for septal release are distinct from those which project to the neurohypophysis.

Animals↗
PubMed1986

Anaplastic carcinoma of urinary bladder with oat cell features.

Anaplastic carcinoma of the urinary bladder, with oat cell-like components, is rare. We report such a tumor in a fifty-nine-year-old man, who died of rapidly disseminated carcinoma in one year despite postoperative radiotherapy and chemotherapy.

Carcinoma↗