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Biomedical subjects

G Patrick

Publications and source records attributed to G Patrick.

At least 55 records · Page 3Linked to original sources
PubMed1988

Stimulus properties of 1-(3,4-methylenedioxyphenyl)-2-aminopropane (MDA) analogs.

Using a standard two-lever operant procedure, groups of rats were trained to discriminate intraperitoneal doses of the phenylisopropylamines (+)amphetamine (1.0 mg/kg) or racemic 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM; 1.0 mg/kg) from saline using a VI 15-sec schedule of reinforcement for food reward. Once trained, the animals were administered doses of several methylenedioxy analogs (MDAs) of phenylisopropylamine including the N-monomethyl [S(+)MDMA and R(-)MDMA], N-monoethyl [(+/-)MDE, S(+)MDE, and R(-)MDE], and the N-hydroxyl [(+/-)N-OH MDA] derivatives. The DOM-stimulus did not generalize to any of these agents. The amphetamine-stimulus generalized to S(+)MDMA, S(+)N-ethylamphetamine and (+/-)N-hydroxyamphetamine, but not to R(-)MDMA, (+/-)MDE, S(+)MDE, R(-)MDE, or N-OH MDA. The present results are consistent with other reports in the literature suggesting that the psychoactive effects of certain MDA derivatives may be other than simply amphetamine- or DOM-like.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗
PubMed1987

Patterns of lymphatic drainage to individual thoracic and cervical lymph nodes in the rat.

Colloidal carbon was used as tracer material to determine the lymphatic drainage to the cervical and thoracic lymph nodes from various regions of the respiratory tract in the F344 rat. While the lung region may be drained mainly to the posterior mediastinal lymph nodes, the tracheal wall drains primarily to the internal jugular and posterior cervical nodes.

Animals↗
PubMed1987

Long-term retention of 133Ba in the rat trachea following local administration as barium sulfate particles.

Long-term retention of 133Ba in the trachea from intratracheally administered BaSO4 particles was determined by both serial sacrifice and external scanning methods up to 6 months after injection. The amount of 133Ba retained 1 week after injection in the caudal region of the trachea, where the tip of the cannula had been at injection, was 0.41% of the initial dose. Thereafter the 133Ba was cleared exponentially with a mean half-time of 88 days, as determined from the autopsy samples. The cranial region of the trachea, including the site of the tracheostomy, contained 133Ba at 10 times the level in the caudal region 1 week after injection and was cleared with a half-time of 66 days. These clearance rates were confirmed by repeated external scanning over the trachea. The 133Ba was drained to the lymph nodes not only in the thoracic cavity but also in the cervical region, suggesting the possibility of lymphatic drainage from the trachea to the cervical lymph nodes.

Animals↗
PubMed1986

A method for microinjection into subpleural alveoli of rat lung in situ.

A new technique is described for the micropuncture of rat lung in the intact thorax. Under pentobarbital sodium anesthesia a glass micropipette is passed through a small area of the parietal pleura, which has been cleared of overlying intercostal muscle. The micropipette is passed into the lung parenchyma and withdrawn again without collapsing the lung. The current application of this technique is in the microinjection of fluid into subpleural alveoli, which is illustrated using a suspension of colloidal gold. The gold particles are immediately dispersed over the surface of many alveoli, a small proportion spreading laterally as far as 4-6 mm. There is no evidence of alveolar flooding.

Animals↗
PubMed1985

Strategic media planning: furthering the impact of health care advertising.

The changing marketplace and the competitive atmosphere makes advertising increasingly necessary for health care providers. Alternative delivery systems are already using the media to promote their products and hospitals will also need to market the services they provide. This article traces the history of health care advertising and outlines how to prepare an effective media plan.

Advertising↗
PubMed1983

Differential inhibitory action by morphine on the release of oxytocin and vasopressin from the isolated neural lobe.

Simultaneous release of both oxytocin and vasopressin was evoked by electrically stimulating the isolated neural lobe. Morphine inhibited the electrically evoked release of both oxytocin and vasopressin, but whereas the opiate antagonist naloxone reversed the suppression of oxytocin release it was without effect against the opiate block of vasopressin secretion. Thus, although the secretion of both neurohypophysial hormones can be suppressed by opiates, the mechanisms may involve different types of receptors. We also provide evidence that, at least for the oxytocin neurones, the presence of endogenous opioid peptides in the neural lobe limits the amount of hormone released by electrical stimulation.

Animals↗
PubMed1980

The localisation of particles retained in the trachea of the rat.

Particles of 133BaSO4 were deposited on the surface of rat trachea by intra-tracheal injection. Aggregates of particles were located in the trachea by autoradiography and electron microscopy. Following deposition, particles not rapidly removed by muco-ciliary clearance remained on the epithelium for some time. After 2 hr most had been ingested by macrophages on the surface, though some were still free in the mucus. By 24 hr, 74 per cent. of the aggregates remaining were beneath the epithelium in the lamina propria, and after 7 days almost all of them were in or beneath the epithelium. All the buried particles identified by EM were within macrophages. After 24 hr the particles in the tracheal wall were beneath epithelium which was not ciliated columnar, but cuboidal or flatter, with fewer or no ciliated cells and infiltrated with lymphocytes. It is suggested that particle retention in airways is accomplished by ingestion by macrophages which then migrate through this type of epithelium.

Animals↗
PubMed1978

The distribution and clearance of inhaled UO2 particles on the first bifurcation and trachea of rats.

The distribution of inhaled UO2 particles is described in the upper respiratory tract of rats up to 14 d after inhalation. Delayed neutron analysis was used to determine accurately nanogram quantities of UO2 present in excised tissues. The mass of UO2 in the extrapulmonary bronchi and first bifurcation decreased more slowly over 0--8 d after inhalation than the corresponding mass on the trachea. Between 8 and 14 d neither amount altered significantly. Small but significant quantities of UO2 deposited on the trachea during inhalation, remained until at least 14 d after inhalation.

Animals↗
PubMed1977

Measurement of mucociliary clearance from the trachea of conscious and anesthetized rats.

A technique is described whereby particles are injected as a suspension into the trachea of conscious rats. Tracheostomy and cannulation are performed under halothane, but the particles are injected 10 min after recovery. Clearance of BaSO4 particles labeled with 133Ba was determined with a collimated slit gamma-counter, either aligned with the region of particle deposition or used to scan along the animal. Compared with clearance up the trachea in conscous rats, the effect of halothane, thiopental and pentobarbital was to inhibit clearance. With halothane, clearance was resumed at the control rate 0-3 min after anesthesia lasting 7-9 min.

Animals↗
PubMed1977

A model for treating post-irradiation nausea and vomiting in man: the action of insulin in abolishing radiation-induced delay in gastric emptying in the rat.

Radiation-induced delay in gastric emptying in rats, which may be comparable to radiation-induced nausea and vomiting in man, can be successfully treated with insulin. Biphasic insulin, given in the appropriate dose for the radiation exposure, restored the rate of emptying to normal and was used instead of soluble insulin which made the stomach empty quicker than normal. Some of the evidence suggests that this effect of insulin is related to its action on carbohydrate metabolism, but there was no simple correlation between the hypoglycaemic action of insulin and its effect on stomach emptying. A complete explanation for this action of insulin cannot be given at this stage but the possible involvement of intestinal hormones, such as enteroglucagon is discussed. It is suggested that the use of insulin to treat radiation-induced nausea and vomiting in man should be considered.

Animals↗