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Biomedical subjects

M Liu

Publications and source records attributed to M Liu.

At least 649 records · Page 36Linked to original sources
PubMed1987

Anatomical analysis of the cause of skin necrosis of the great toe after transplantation of the great toe nail flap.

Necrosis of skin on the medial side of the great toe has been a significant complication of the great toe nail flap. To investigate the reason for this, a study of the blood supply of the medial side of the great toe was carried out on 55 feet with the injection of red latex into the arteries and on 13 vascular cast specimens. It was found that, after the blood vessels from the plantar and dorsal sides of the great toe are severed during the operation, the skin of the medial side of the great toe is mainly supplied by the medial vascular network at the head of the first metatarsal bone. It is clear that the blood supply from this network may sometimes be insufficient to nourish the skin. It is suggested that the operative incision should be changed so as to increase the blood supply to the medial vascular network which may decrease the incidence of skin necrosis.

Humans↗
PubMed1987

Enalaprilat, a new parenteral angiotensin-converting enzyme inhibitor: rapid changes in systemic and coronary hemodynamics and humoral profile in chronic heart failure.

Systemic and coronary hemodynamic, metabolic and humoral effects of a new intravenous angiotensin-converting enzyme inhibitor, enalaprilat, were evaluated in 14 patients with chronic heart failure. Onset of hemodynamic action occurred within 15 minutes and persisted for 6 hours. At the time of peak effect, there was a significant reduction in mean arterial pressure (-21%) and pulmonary capillary wedge pressure (-33%). Systemic vascular resistance decreased by 32% and stroke volume index increased by 20%. These systemic hemodynamic changes indicate improved left ventricular function. There was a substantial sustained reduction in rate-pressure product initially without a change in coronary sinus blood flow or myocardial oxygen consumption. There was also reduced myocardial oxygen extraction and augmented coronary sinus oxygen saturation at 30 minutes and 1 hour. In three patients, abnormal myocardial lactate extraction, present before enalaprilat, changed to uptake after enalaprilat, indicating amelioration of myocardial ischemia that was not clinically manifest. Systemic catecholamine levels and myocardial catecholamine balance did not change. Plasma renin activity increased and plasma aldosterone decreased. These findings suggest that enalaprilat produces inhibition of the angiotensin-converting enzyme and consequent beneficial systemic hemodynamic changes in heart failure. In some patients with heart failure, silent myocardial ischemia at rest can occur and can be alleviated with enalaprilat. Decreased myocardial oxygen extraction, increased coronary sinus oxygen saturation and lack of expected decrease in coronary sinus blood flow despite reduced rate-pressure product suggest transient coronary vasodilation by enalaprilat.

Aged↗
PubMed1986

Use of procyclic trypanosomes for detection of antibodies in sera from vervet monkeys infected with Trypanosoma rhodesiense: an immunodiagnostic test for African sleeping sickness.

Uncoated procyclic culture forms of African trypanosomes were used in immunofluorescence and simple agglutination assays to detect antibodies in the sera of vervet monkeys infected with T. b. rhodesiense. Antibodies to procyclic surface antigens were found in sera from animals with active, untreated infections or sera taken soon after treatment with trypanocidal drugs. The antibodies were detectable within 7 days of infection. No specific antibodies were detected in sera prior to infection or long after drug cure. The results indicate that antigens expressed on the surface of procyclic culture forms of T. brucei spp. are useful for the detection of antibodies produced in response to infection with T. b. rhodesiense and may allow the development of a simple immunodiagnostic test for African sleeping sickness. In addition, the use of a form of the trypanosome of a different differentiation state from the infecting organism illustrates the utility of this approach for detection of antibodies to common antigens.

Agglutination Tests↗
PubMed1983

Photobiological activity of 5,7-dimethoxycoumarin.

Some biological properties of 5,7-dimethoxycoumarin (DMC) include dark induced frameshift mutagenesis in bacteria, lethal photosensitization and the formation of sister chromatid exchanges in Chinese hamster cells. The number of sister chromatid exchanges per unit of cell lethality produced by DMC is almost the same as observed with 5-methoxypsoralen.

Animals↗
PubMed1982

Photobiological studies with dictamnine, a furoquinoline alkaloid.

Dictamnine, a naturally occurring furoquinoline, produces bacterial frameshift mutations in the dark. It does not form DNA interstrand crosslinks in bacterial cells in the presence of near-ultraviolet light (300-380 nm). It is more active than angelicin but slightly less active than 8-MOP as a phototoxic agent with E. coli. It is however a more active mutagen than 8-MOP at equivalent concentration. Dictamnine is slightly more potent than the same concentration of angelicin in producing photosensitized lethality in Chinese hamster cells. It does, however, produce almost twice as many sister-chromatid exchanges per lethal event than angelicin. The concept of 'unit dose' relating the observable photoinduced damage by the photosensitizer and the total irradiation appears to apply reasonably well to the actions of dictamnine in killing bacterial and mammalian cells, in the formation of sister-chromatid exchanges, but not to the induction of bacterial mutations.

Alkaloids↗
PubMed1982

Microbial products. VI Five novel metabolites related to benz[a]anthracene from an unidentified actinomycete designated X-14881.

Five metabolites of actinomycete X-14881 were isolated from the fermentation broth and characterized. The major component was identified as [3R-(3 alpha,6a beta,7 beta,12 alpha,12a alpha)] or [3S-(3 beta,6a alpha, 7 alpha,12 beta,12a beta)]-6a, 7,12-trihydroxy-3,4,6a, 7,12, 12a-hexahydro-8-methoxy-3-methylbenz[a]-anthracen-1(2H)-one; the other four are closely related derivatives thereof.

Actinomycetales↗