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Biomedical subjects

C Galeano

Publications and source records attributed to C Galeano.

35 records · Page 2Linked to original sources
PubMed1983

Response of urethral smooth muscles to pharmacological agents. II. Noncholinergic, nonadrenergic agonists and antagonists.

We studied the effects of a variety of noncholinergic, nonadrenergic agents on the smooth muscles of the cat urethra. Prostaglandin F2 alpha contracted both urethral muscle layers to a similar extent. Prostaglandin E2 contracted the longitudinal and relaxed the circular muscle layers. The effects of the prostaglandins seem to be directly myogenic since cholinergic and adrenergic blockers and tetrodotoxin did not affect them. Bradykinin and substance P contracted both urethral muscle layers. Other tested agonists (neurotensin, vasoactive intestinal peptide, cyclic 3,5 adenosine monophosphate, adenosine diphosphate sodium, cyclic 3,5 guanosine monophosphate sodium, bombesin) had no effect on the cat urethral smooth muscles.

Animals↗
PubMed1983

Response of the urethral smooth muscles to pharmacological agents. I. Cholinergic and adrenergic agonists and antagonists.

We studied the effects of cholinergic and adrenergic agents on the 2 muscle layers of the proximal urethra of the cat. Strips were challenged with bethanechol chloride, phenylephrine and isoproterenol. Bethanechol chloride caused contraction of the longitudinally oriented strips; the circularly oriented strips revealed either minimal or no response to the same doses. The difference between the response of the 2 layers was highly significant (p less than 0.001). Phenylephrine stimulated both layers with a nonsignificant difference. Isoproterenol caused relaxation of both layers with a significant action on the circularly oriented fibers (p less than 0.05). It could be concluded that the cholinergic effect which is predominant on the longitudinal fibers is important for voiding by shortening the proximal urethra. alpha-adrenergic innervation of the bladder neck has a function during ejaculation: closure of the bladder outlet by the circular fibers. beta-adrenergic agonists decrease the urethral pressure probably by relaxing both layers with a dominant effect on the circular layer.

Animals↗
PubMed1983

Effects of intensity of stimulation on signs of acute ischemia in the electroretinogram.

Acute retinal ischemia was induced in adult albino rabbits by clamping the retrobulbar blood vessels or raising the intraocular pressure. As the level of ischemia was increased, the b-wave amplitude and implicit time of response increased. However, the hyperresponsivity and delay of response were inversely related to the intensity of stimulation used, although at levels of ischemia above 70% there was a significant delay of response even with high-intensity stimulation. Thus, if early signs of acute ischemia are to be successfully monitored, low intensities of stimulation must be used.

Acute Disease↗
PubMed1983

[Vesicourethral physiology during continence and urination in cats. In vivo and in vitro studies].

The mechanisms implicated in the opening of the bladder neck during voiding are still controversial. We present a study of the reflexes of bladder, urethra and periurethral striated muscles in the cat. The study in vivo shows that a passive muscle tonus of the urethra is able to maintain the continence. During voiding, opening of the bladder outlet is done actively: contraction of the longitudinal and relaxation of the circular muscle layers of the urethra associated with detrusor contraction. There is a local reflex between the urethra, bladder and periurethral striated muscles that completes emptying of the bladder with an interrupted stream. The study in vitro confirms that the 2 muscle layers of the urethra have different innervation: the parasympathomimetic agents act on the longitudinal layer and very weakly on the circular. Both layers react to adrenergic stimulation.

Animals↗
PubMed1983

Hyper-response and delay in the electroretinogram in acute ischemia.

Acute ischemia was induced in 11 adult albino rabbits by clamping the retrobulbar blood vessels and in 5 others by raising the intraocular pressure. Total ischemia was achieved by raising the pressure in the hydraulic remote control system until total collapse of the retinal circulation was observed by indirect ophthalmoscopy and the response on the electroretinogram (ERG) disappeared. The level of ischemia was increased by 15% increments from 25% to 100%, and ERGs were recorded with a constant intensity of stimulation. The amplitude increased up to a peak at 55% ischemia, then decreased to extinction at 100% ischemia. The time of response increased to a maximum at 100% ischemia. The tentative conclusion is drawn that it is important to appreciate that ischemia, and not just degeneration, can cause a delay of the ERG response in humans.

Animals↗
PubMed1982

Vesicourethral electromyography: facts or artefacts.

A vesicourethral electromyographic study was carried out on 21 cats of both sexes with extracellular electrodes along with monitoring of contraction and relaxation of various parts of the bladder and urethra. No consistent electromyographic pattern of slow and fast waves was observed in the bladder and urethra either in any empty bladder or during filling and voiding phases. Most of the recorded waves were traced to a defined source of artefact. Twenty-two experiments were done with glass microelectrodes recording intracellularly in bladder strips of various animals bathed in normal and modified Krebs solutions. No spike activity was recorded during periods of contractions, whether spontaneous or electrically stimulated. Both in vivo and in vitro experiments suggest that the mechanism of excitation-contraction coupling of the bladder remains unidentified. The clinical application of bladder electromyography (EMG) has to be interpreted cautiously.

Action Potentials↗
PubMed1981

A new approach to the study of the voiding cycle in the cat.

Physiologic studies were carried out on 51 anesthetized cats. We monitored contraction and relaxation with force displacement transducers, recording individually from bladder, longitudinal, and circular urethral smooth muscle layers; and intravesical pressure with a pressure transducer. During constant slow vesical filling with warm saline the urethral muscle tone, without increased motility, was capable of maintaining continence. At the prevoiding stage, the circular urethral muscle contracted and the longitudinal relaxed for 1 to 2 sec, which tightened the bladder neck and resulted in the creation of isovolumetric bladder pressure stage. The voiding was accomplished by bladder pressure augmentation, bladder muscle contraction, and synergic contraction of longitudinal and relaxation of circular urethral muscles. A transient urethral pressure drop preceded the urethral pressure rise of the isovolumetric stage of voiding. The smooth urethral muscle motility pattern during voiding was reproduced without fluid flow per urethrum by the inflation of a balloon in the bladder.

Animals↗
PubMed1979

Acupuncture analgesia in rabbits.

The aim of this study was to verify the validity and reliability of analgesia elicited by acupuncture stimulation in rabbits. Ninety-five experiments were performed using 21 adult animals. The reaction time of the avoidance response elicited by noxious heat stimulation on the snout, and the presence or absence of the start response elicited by pin-prick and clamping of the skin were studied. Bilateral electric acupuncture stimulation in the area of Tsu-san-li and Shang-chu-hsu points in the hind legs was used. The animals were either held in a soft bag, loosely attached by cords, or suspended in a hammock; the eyes were either free of blindfolded. On the basis of operational behavioral measurements, it was found that acupuncture stimulation did not produce analgesia in undisturbed, placid animals. However, during agitated or fighting periods and the immobility reflex-like state, sometimes associated with acupuncture maneuvers, long reaction times were observed. Pin-pricking and clamping stimulation of the skin were not reliable methods of noxious stimulation in the rabbit.

Acupuncture Therapy↗
PubMed1977

Activity of the crayfish caudal photoreceptor submitted to a conditioning paradigm.

The activity of the crayfish caudal photoreceptor (Ph) was studied during the application of a classical conditioning paradigm. This cell is a primary photoreceptor and, at the same time, a secondary neuron in the mechanoreceptive pathway. The electrical stimulation of afferent mechanoreceptor fibers, the analog of the conditioned stimulus (ACS), produced a slight increase in the Ph firing rate. The photic stimulation, the analog of the unconditioned stimulus (AUS), produced a marked increase in the Ph firing rate. After ACS-AUS pairing, a decrease in the Ph firing rate appeared during the ACS-AUS interval, and it was considered the analog of the conditioned response (ACR). This inhibitory response gradually vanished during extinction. The application of ACS or AUS series alone did not produce a response similar to the ACR, this excluding sensitization as a possible cuase. The ACR meets several conventional criteria accepted in learning, supporting the idea that the crayfish caudal photoreceptor is part of a small neuronal network able to learn in the isolated nerve cord preparation.

Animals↗
PubMedDate not supplied

[Epidemiologic study of cervico-vaginal pathology in IUD users].

1800 intrauterine contraceptive device users, during a period of more than thirteen years, and 1800 control non-users were examined clinically, cytologically and histopathologically for cervical pathological lesions. There was an increase, but not statistically significant, in the incidence of metaplasia, dyskariosis or mild dysplasia. There was no difference in neoplastic lesions.

Adult↗