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Biomedical subjects

K Grant

Publications and source records attributed to K Grant.

At least 91 records · Page 5Linked to original sources
PubMed1983

Effect of 5-hydroxydopamine on the large dense-cored vesicles in the axon terminals of the myenteric ganglia of the guinea-pig stomach.

Quantitative ultrastructural analysis revealed that the large dense-cored vesicles in the axon terminals in the myenteric ganglia of the guinea-pig stomach tend to be concentrated towards the ends of the terminals. In guinea-pigs treated with 50 mg/kg 5-hydroxydopamine, diameters of the vesicles were increased and their distribution in the terminals was altered. Treatment with reserpine prior to 5-hydroxydopamine increased the proportion of large dense-cored vesicles and decreased the overall number of vesicles in the terminals. The diameter of the vesicles was increased both in the terminal profiles and in the non-terminal segments of the axons. These observations are consistent with the view that uptake of 5-hydroxydopamine into small vesicles is followed by their transformation into large dense-cored vesicles.

Animals↗
PubMed1983

Cimetidine-induced hemolytic anemia: the fallacy of clinical associations.

Two patients developed hemolytic anemia while taking cimetidine. Neither patient was taking other drugs known to cause hemolytic anemia. In both, the hemolytic anemia resolved after the drug was stopped. In one patient, the direct antiglobulin (Coombs') test was strongly positive when the hemolytic anemia was recognized and became only weakly positive as the hemolysis subsided. However, serologic studies for antidrug antibodies yielded negative results in both patients; readministration of cimetidine for 55 days in patient 1 and for more than 24 months in patient 2 did not cause recurrence of hemolysis. We conclude that we cannot incriminate cimetidine as the cause of the hemolytic anemia in either of our patients. These findings emphasize that a temporal association of drug administration and hemolytic anemia is not proof of a cause-effect relationship and that reports of drug-related adverse hematologic effects must be interpreted with caution.

Adult↗
PubMed1983

Convergence of trigeminal afferents on retractor bulbi motoneurones in the anaesthetized cat.

Retractor bulbi motoneurones were identified by intracellular recording of their antidromic invasion following stimulation of the motor axons. Characteristics of excitatory post-synaptic potentials (e.p.s.p.s) evoked by electrical stimulation of long ciliary nerves (corneal afferents), the supraorbital nerve and the ipsilateral or contralateral vibrissae were analysed. Comparison of the orthodromic responses induced by supra-threshold stimulation of the four trigeminal inputs showed that the most powerful excitatory effect was due to corneal afferent stimulation. Excitatory synaptic potentials were followed in some cases by a period of hyperpolarization lasting 15-20 msec. It is suggested that this is an inhibitory potential of post-synaptic origin. Interaction between condition and test e.p.s.p.s evoked by long ciliary nerve and supraorbital nerve stimulation revealed a partial blocking of test e.p.s.p.s over a longer period (more than 30 msec), and it is suggested that inhibitory mechanisms within the trigeminal nucleus may be in part responsible for the absence of facilitation at the level of the motoneurone.

Action Potentials↗
PubMed1982

Distribution and diameter of large dense-cored vesicles in axon terminals in the myenteric ganglia of the mouse and hamster stomach.

The distribution and diameter of the large dense-cored vesicles in axon terminals in the myenteric ganglia of the mouse and hamster stomach were analyzed in electron micrographs of groups of 150 terminal profiles. In the mouse, the vesicles were proportionately more numerous and larger than in the hamster; they were also larger in terminal profiles containing more than 20% of the vesicles. There was no evidence of bimodality of the distribution curve of the proportion of large dense-cored vesicles/profile in either animal. The presence of a significant degree of skew of the distribution curves was indicative of uneven distribution of the vesicles in the terminals, and the occurrence of a significant inverse correlation between the proportion of large dense-cored vesicles/profile and both the diameter of the profiles and the total number of vesicles/profile was in agreement with subjective evidence of a tendency towards accumulation of the vesicles at the ends of the terminals.

Animals↗
PubMed1981

Photochemotherapy of psoriasis with methoxsalen and longwave ultraviolet light (PUVA).

The effectiveness of methoxsalen and ultraviolet light (PUVA) in treating is reviewed. The use of this therapy, its mechanism of action, pharmacology, pharmacokinetics, adverse reactions, dosage, and comparison with other forms of therapy, are discussed. Administered orally, methoxsalen in combination with long-range ultraviolet light (UVA) is effective in treating patients with moderate to severe forms of psoriasis. Although the short-term risks associated with PUVA therapy are minimal, the long-term risks of oncogenicity have not been evaluated thoroughly. Common adverse reactions to methoxsalen and UVA are nausea, pruritus, and erythema, but usually they can be managed by minor modifications in the treatment regimen. Methoxsalen and UVA therapy should be reserved for patients with moderate to severe forms of psoriasis that do not respond to other forms of therapy until the long-term risks of oncogenicity are evaluated.

Humans↗
PubMed1979

[Oculomotor reflex evoked by vibrassae stimulation in the cat].

The oculomotor effects of vibrissae stimulation have been studied in the "encéphale isolé" non-anaesthetized Cat. Intracellular recording of lateral rectus motoneurones showed an excitatory projection via the ipsilateral infraorbital nerve to these motoneurones. The afferent fibers are type A alpha, recuited with a low threshold (0.2-0.5 mA) and convey information about vibrissae displacement.

Afferent Pathways↗
PubMed1979

[Interaction between the vestibulo-ocular and the oculomotor systems].

Optomotor nystagmic activity has been elicited in the "encéphale isolé" cat during repetitive electric stimulation of selective oculomotor regions of the frontal cortex and superior colliculus. These regions were nystagmogenic only when facilitated by a cortical arousal or a vestibular activation.

Animals↗
PubMed1979

Anatomical and electrophysiological identification of motoneurones supplying the cat retractor bulbi muscle.

Motoneurones innervating the retractor bulbi muscle in the cat have been identified by retrograde labelling with horseradish peroxidase, by intracellular recording and by intracellular staining with horseradish peroxidase. Their somata are found in an accessory abducens nucleus, analogous to that described in some other species, which consists of a narrow column of cells situated in the lateral tegmental reticular field, above the superior olive and medial to the facial nerve. The column of cells extends over approximately 1.5 mm from P 5.5 to P 7. The retractor bulbi motoneurones number from 80 to 120 and have large, elongated somata which give rise to five or six major dendrites. Their axons cross the reticular formation in a dorso-medial direction to pass through the principal abducens nucleus before turning to leave the brain stem in the 6th nerve. Antidromic latencies ranged from 0.4 to 0.7 ms. Some retractor bulbi motoneurones could also be activated antidromically by stimulation of the lateral rectus muscle nerve.

Abducens Nerve↗
PubMed1979

Morphological characteristics of lateral rectus motoneurones shown by intracellular injection of HRP.

The morphology of identified lateral rectus motoneurones is described after staining by intracellular iontophoresis of horseradish peroxidase. Soma vary in shape and size according to the number and orientation of primary dendrites. The basic pattern of arborisation shows short primary dendrites which branch close to the soma, forming a distal ramification extending over 600 to 1,200 micrometer from the soma. Distal dendrites extend into the ipsilateral medial vestibular nucleus, the reticular formation and amongst the fibres of the medial longitudinal fasciculus. This extension is greater than that previously seen in procion yellow and Golgi stained lateral rectus motoneurones. The axon originates from the perikarya or from the base of a primary dendrite. No axon collaterals have been observed.

Abducens Nerve↗
PubMed1978

Altered factor VIII complexes in patients with acute respiratory insufficiency.

Acute respiratory failure is an often-fatal syndrome of multiple etiologies in which altered factor VIII may be a marker of endothelial disease. 12 women with overwhelming viral pneumonia were studied with serial factor VIII antigen, procoagulant activity, and von Willebrand's factor assays. Antigen levels were elevated (range: 86--1644%) out of proportion to procoagulant activity (range: 35--521% by a one-stage assay), and factor VIII antigen to activity ratios were as high as 16:1. Von Willebrand's factor was normal but correlated best with procoagulant activity. All patients had abnormal antigen patterns on crossed immunoelectrophoresis, with increases in protein of both fast and slow mobility. These changes in factor VIII correlated with the patient's clinical courses.

Acute Disease↗
PubMed1978

Comparison of quinestrol and Tace for relief of postpartum breast discomfort.

A single 2-mg dose of quinestrol was demonstrated safe and effective for controlling postpartum lactation and for alleviating breast discomfort. A double-blind comparison to Tace 72 mg every 12 hours for 2 days, and to placebo, was made in 134 patients. The single oral dose of quinestrol showed efficacy equal to the 2-day regimen of Tace. Both were superior to placebo.

Adolescent↗
PubMed1978

A practical method of antimicrobial surveillance.

This antimicrobial surveillance program clearly relates inpatient antimicrobial usage to therapeutic or prophylactic indications. One nurse-epidemiologist gathers data for a medium-sized Veterans Administration hospital, in addition to carrying out infection surveillance and educational responsibilities, and reviews the data weekly with an infectious disease physician. Usage of antimicrobials for surgical prophylaxis is the area where violations of generally accepted criteria for usage can be most readily documented. Only 31% of usages were deemed appropriate. A similar percentage (about 65%) of antimicrobial usages were judged "appropriate" on the medical and surgical services in treatment of wound and urinary tract infection. Treatment of respiratory tract infection and sepsis was judge "appropriate" in over 85% of instances on the medical service. These categories contained too few cases to summarize on the surgical service.

Aminoglycosides↗