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Biomedical subjects

G Morgan

Publications and source records attributed to G Morgan.

At least 325 records · Page 18Linked to original sources
PubMed1980

Incidence of Duchenne muscular dystrophy in New South Wales and Australian Capital Territory.

A survey was conducted during 1977 to 1978 to determine the incidence of Duchenne muscular dystrophy in New South Wales and the Australian Capital Territory. Ninety-nine cases born between 1960 and 1971 were ascertained representing an incidence rate of 18.6 per 100 000 liveborn males. Over 60% of the ascertained males were isolated cases, and only 7% of affected males had an affected males relative in a previous generation in the female line. Categorisation of ascertained cases as either "theoretically preventable" or not shows that genetic counselling alone in the present circumstances is insufficient to reduce the incidence rate significantly.

Australia↗
PubMed1980

An endemic neurological disorder in tribal Australian aborigines.

Thirteen, and possibly sixteen cases of neurological disorder have been identified in a population of approximately 1100 tribal aborigines living in Groote Eylandt and the adjacent mainland. There were two relatively distinct clinical pictures: one coming on in childhood involved the motor system, the patients often having remarkably lax ligaments; and the other, generally of later onset, comprising cerebellar, upper motor neurone and sometimes supranuclear ophthalmoplegic features. There was some evidence that the two syndromes are varieties of a single condition. No causal factors were identified but there were indications that the disorder might be genetically determined. Attention is drawn to the similarities between this disorder and other ethnic-geographic isolates, particularly the ALS-Parkinsonism-dementia complex of Guam.

Adolescent↗
PubMed1980

Histology of the camel eye.

The camel eye shows some distinct features such as a pigmented peripheral cornea, a remarkably thickened Descement membrane, and endothelial-lined pectinate ligament, a cleft ciliary body, long ciliary processes, a horizontally oval pupil with well-developed corpora nigra and a holangiotic retina. Some of these are characteristic of horses, cattle and sheep, whereas others are more commonly found in lower mammals such as the rabbit. The reason for this staggered evolution in the development of the camel eye remains obscure.

Animals↗
PubMed1979

Antihypertensive and cardiac effects of two novel beta-adrenoceptor blocking drugs.

Two new beta-adrenoceptor blocking drugs with acute antihypertensive and positive inotropic effects are described: Compound A (2-[4-(3-tert.butylamino-2-hydroxypropoxy)phenyl]-4-trifluoromethylimidazole) and MK-761 (2-(3-tert.butylamine-2-hydroxypropoxy)-3-cyanopyridine hydrochloride). In SH rats both compounds, given orally, lowered arterial pressure and were more potent than hydralazine. The antihypertensive effect of compound A but not of MK-761 was antagonized by timolol. Both compounds had positive inotropic activity on cat heart papillary muscles; these effects were antagonized by timolol. The pretreatment of animals with reserpine greatly reduced the positive inotropic effect of MK-761 but not of compound A. The acute antihypertensive and positive inotropic effects of compound A are like to be at least partially due to stimulation of beta-adrenoceptors, e.g. intrinsic sympathomimetic activity. The effects of MK-761 on the same parameters appear to be mediated by different mechanisms.

Adrenergic beta-Antagonists↗
PubMed1979

Antihypertensive activity of some novel pyridinylidene arylurea derivatives in spontaneously hypertensive rats.

3 novel pyridinylidene arylurea derivatives were found to lower arterial pressure in spontaneously hypertensive rats. Their relative oral potency ranged from 6 to 32 times that of guanethidine. The onset of antihypertensive action following their oral administration was less than 1 h and the duration of action ranged from 8 to over 24 h. The antihypertensive activity of the pyridinylidene arylureas was found to be assoicated with depletion of tissue catecholamines. Compound C depleted cardiac norepinephrine with little or no effect on total brain norepinephrine levels. It is suggested that compound C may have useful antihypertensive properties without CNS depressant activity.

Animals↗
PubMed1979

Antihypertensive and other cardiovascular effects of 2-(3-pyridyl)- and 2-(4-pyridyl)-4-trifluoromethylimidazoles.

2 new 4-trifluoromethylimidazole derivatives were found which lowered mean arterial pressure in renal and spontaneously hypertensive (SH) rats by the oral route. In SH rats, compounds A and B were 0.1 and 0.3 times, respectively, as potent as hydralazine. No tolerance development was observed in SH rats with either compound over a 1-week period. In anesthetized dogs, both compounds lowered arterial pressure and peripheral vascular resistance but increased cardiac output. By intraarterial administration, both compounds increased femoral arterial blood flow. These findings represent discovery of a new class of vasodilator durgs.

Animals↗
PubMed1979

Septicemia in patients with an endocardial pacemaker.

The records of 1,235 consecutive patients treated with long-term pacing by the endocardial route between 1964 and 1977 were analyzed to determine the incidence, mechanism, course and treatment of septicemia. Septicemia developed in 12 patients (1 percent), and Staphylococcus aureus was isolated from the blood culture in 10. All patients were treated with the usual prolonged course of bactericidal drugs. Treatment was successful in only two of the seven patients whose endocardial pacing system was left in place; in three of the seven the septicemia recurred, necessitating removal of the endocardial system, and two of these patients died. In the remaining four patients the endocardial wire was promptly withdrawn, with use of a thoracotomy when necessary, and an epicardial system inserted; all of these patients survived. This is the treatment of choice.

Adult↗
PubMed1979

Errors in fuel cell oxygen analysers during NEEP.

A fuel cell oxygen analyser was found to underread during the application of negative end-expiratory pressure. Further investigation revealed that air leaks into the analyser head through the plastic housing and causes the analyser to read low. A remedy is suggested.

Oxygen↗
PubMed1979

Mitochondria and mitochondria-tonofilament-desmosomal associations in the mammary gland secretory epithelium of lactating cows.

The lactating cow mammary secretory epithelial cell is very active synthetically and contains numerous very pleomorphic mitochondria. Cup- and ring-shaped mitochondria are frequent and many are extremely elongated. Preferential localization of mitochondria in the basal region, or at the lateral margins of the secretory cell adjacent to intraepithelial monocytes have been observed. Occasional mitochondria show one or several very densely staining cristae with a lattice pattern. Mitochondria are frequently seen closely associated with the tonofilament-desmosomal complex. These structures and associations are present after immersion or perfusion fixation of mammary gland from several breeds of cow; their possible significance is discussed.

Animals↗
PubMed1979

Beta adrenoceptor blocking properties of MK-761.

MK-761 is a new class of compound which has beta adrenoceptor antagonist and vasodilating properties in a single molecule. The compound has in vitro beta adrenoceptor blocking activity in the isolated cat heart papillary muscle and isolated rat atria. Unlike propranolol, it did not depress contactile force. Intrinsic sympathomimetic activity was not observed in vitro, (isolated cat papillary muscle, isolated atria) but the compound has some intrinsic sympathomimetric activity because it slightly increased heart rate in reserpinized rats. MK-761 was found to be approximately as potent as timolol and pindolol in blocking cardiac and vascular beta adrenergic receptors in anesthetized dogs. The drug was not, however, cardioselective. Oral beta adrenoceptor blocking activity was observed in rats at doses similar to those which decreased blood pressure.

Adrenergic beta-Agonists↗
PubMed1978

The effect of labetalol in the treatment of severe drug-resistant hypertension.

Twenty-two hypertensive patients from a large clinic, who were resistant to conventional therapy, were entered into this study. Most patients previously had received beta-blocking drugs, thiazide diuretics, alpha-methyl-dopa, or vasodilator drugs (hydrallazine or prazosin) which failed to control their blood pressure. The therapy with vasodilator drugs was discontinued, and the therapy with labetalol (a drug with both alpha-blocking and beta-blocking effect) was commenced. Subsequently, as the blood pressure came under control, other drugs that the patients were taking were also withdrawn. In 13 of the 22 patients, labetalol enabled the blood pressure to be controlled at acceptable levels. In six patients, the response was not considered to be sufficient to justify continuation of labetalol therapy. In three patients, the drug was withdrawn because of postural hypotension in one patient, intractable diarrhoea in another, and an allergic-type skin rash in the third. In certain patients, postural changes in blood pressure were observed, but this rarely produced symptoms. It is suggested that, if blood pressure control is not achieved with a thiazide diuretic and a beta-blocking drug, then labetalol should be introduced and the beta-blocking drug should be withdrawn.

Aged↗
PubMed1978

Hypertension treated by salt restriction.

31 patients with a diastolic blood-pressure between 95 and 109 mm Hg have been treated for two years with a regimen involving a moderate restriction of salt in the diet. The results are compared with those in a control group and in a drug-treated group. Salt restriction has reduced the diastolic blood-pressure by 7.3+/-1.6 mm Hg, a result similar to that in patients treated with antihypertensive drugs. In the untreated group the diastolic blood-pressure rose by 1.8+/-1.1 mm Hg. Most patients did not achieve the desired amount of salt restriction and a stricter adherence to the diet might have caused further falls in blood-pressure. Excessive salt intake is probably a major cause of the epidemic of hypertension in "civilised" countries and a reduction in salt intake may help to control the epidemic. In persons with a diastolic blood-pressure between 90 and 105 mm Hg salt restriction should be tried before drugs.

Blood Pressure↗