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Biomedical subjects

E Anyanwu

Publications and source records attributed to E Anyanwu.

29 records · Page 2Linked to original sources
PubMed1983

Myocardial intra- and extracellular calcium changes following cardioplegic cardiac arrest.

To study the behavior of myocardial cellular calcium during the course of myocardial ischemia following cardiac arrest induced by the chemical cardioplegia, LK352, transmural biopsies were made from the apex of the left ventricle of nine patients undergoing electric cardiac surgery. The biopsies were made before the onset of extracorporeal circulation, at the end of ischemia, and after the discontinuation of cardiopulmonary bypass following reperfusion and cardiac resuscitation. Ultrastructural studies focused on the pattern of distribution in the interstitial space of a certain combination of elements forming microcrystals, together with a quantitative intracellular calcium assay, based on electron probe X-ray microanalysis, presented the following results: In the course of ischemia, a highly significant depletion of intracellular calcium was associated with the pooling of calcium in the interstitial space. An intracellular calcium assay following coronary reperfusion with systemic blood demonstrated intracellular calcium replenishment in association with the depletion of the calcium which had accumulated in the interstitial space during ischemia. The intracellular concentration of calcium after reperfusion approximated the control value. Based on our results, we consider the intracellular calcium depletion a mechanism which keeps the heart arrested in the diastole.

Adult↗
PubMed1982

Mineralization of human aortas with coarctation: quantitative electron probe microanalysis.

Aortas with coarctation (isthmus stenosis) are obviously an ideal model to investigate pressure dependent changes of the aorta, as one can compare the proximal region (high pressure) with the distal region (low pressure). 7 aortas of patients aged from 2 months to 54 years were investigated. The concentrations of Na, Mg, P, S, C1, K, and Ca were determined by electronprobe microanalysis. Ca and P are constituent parts of the developing mineral and are mainly discussed. The Ca/P ratio (by weight) is about 0.3 in the unmineralized and about 2 in the mineralized tissue. Mineralization is demonstrated by a parallel increase of Ca, P, and the Ca/P ratio. Enrichments of Ca and P are found above all in a subintimal band. Usually they occur proximally and distally, but are much more pronounced proximally. Even in the aorta of a 2 month old infant enrichments were found proximally, but not distally. Thus mineral deposits occur very early in regions of hypertension. The differences between the proximal and distal region may demonstrate the influence of blood pressure on vascular mineralization. The mineralization starts in small compartments, which increase in size and number in the process of mineralization. Mineralized regions could often be localized by cathodoluminescence. But to demonstrate and localize the initial mineral deposits and to quantify element contents, electronprobe microanalysis became indispensable.

Adolescent↗
PubMed1981

Coarctation of the aorta. A risk factor in children for the development of arteriosclerosis.

Pressure recordings in 120 patients, aged 0-35 years, undergoing operation for coarctation of the aorta, show a slow but steady rise in both systolic and diastolic peak pressures, the highest peak registered being in patients aged 16-18 years. The finding of significant morphological changes in the aorta in this age group is the rule and these arteriosclerotic changes become more severe as the patients get older. In long-standing coarctation, the degree of mineralisation proximally is up to 10 times higher than distally. The microscopic and ultrastructural changes in the proximal segment are essentially arteriosclerotic. In conclusion, the role of coarctation of the aorta in the pathogenesis of arteriosclerosis is essentially that of hypertension, a most important risk factor of arteriosclerosis. Since arteriosclerosis also develops in the region of low blood pressure, other factors are operative. We suppose that the reduced pulse and volume pressures, which in turn diminish the "windkessel" function of the aorta may effect a change in the blood flow patterns to favour the development of arteriosclerosis.

Adolescent↗
PubMed1981

[The behaviour of the granular alveocytes in chronic pulmonary congestion, pulmonary fibrosis and after extracorporeal circulation (author's transl)].

The granular alveocytes, known to be the site of the production of the surfactant, undergo characteristic changes following chronic pulmonary congestion and the succeeding fibrosis, and after extracorporeal circulation. Congestion is accompanied by cell edema and the breakdown of the lamellar bodies. With fibrosis the cells are shrunken and present with little if any lysosomes. The nuclei are pyknotic or demonstrate karyolysis. Vacuolar degeneration of the lamellar bodies and progressive degeneration of the mitochondria are observed. The extracorporeal circulation damages many granular alveocytes. The degree of damage correlates with the duration of the cardiopulmonary bypass and with the degree of the prepump pathological changes present in the lungs. On the other and the extracorporeal circulation induces in the intact cells enhanced surfactant production, during which the different developmental stages of the lamellar body increasingly accumulate within the cell. In conclusion, pulmonary congestion and fibrosis reduce the activity of the granular alveocytes. The extracorporeal circulation enhances structurally favourable conditions in the granular alveocytes for the increased release of the surfactant in the immediate post-operative phase - a process which could be regarded as an autoregulatory mechanism.

Adult↗
PubMed1979

[Experimental and clinical employment of an endovenous-myocardiac screwing electrode (author's transl)].

A common postoperative complication following transvenous endocardial pacemaker implantation is the dislodgement and displacement of the electrode. Following trial of a new endovenous-myocardiac screwing electrode in dogs we have tried this electrode since December 1976 on 105 patients, of which 84 cases were implanted primarily and 21 secondarily. The average stimulation threshold was 0.7 V at a pulse width of 1 ms. 6 patients had complications. By making a judicious use of this electrode the rate of electrode dislodgement can be reduced appreciably.

Adult↗
PubMedDate not supplied

Ultrastructural changes in the human lung following cardiopulmonary bypass.

In order to assess the degree of the pathological changes presenting in the lungs of patients after elective cardiac operations in cardiopulmonary bypass and to determine their prognosis, lung biopsies were taken from the right lower lobe of 36 patients after extracorporeal circulation and studied ultrastructurally. Prepump biopsies from the same presenting anterior portion of the lower lobe of the lung served as controls. Perivascular and interstitial edema featured prominently. Intraalveolar edema and extravasated corpuscular blood elements were observed, too. Damages to the mitochondria and to the lamellar bodies and swelling of the endothelial and alveolar cells were major observations following cardiopulmonary bypass lasting more than 60 minutes. These changes were also prominent in those lungs presenting with severe edema and fibrosis. Many intact type-II pneumocytes presented with enhanced metabolic and secretory activities. Merocrine and apocrine secretions were observed after extracorporeal circulation. The alveoli of the postpump lungs contained numerous detached normal appearing type-II pneumocytes, in contrast to the paucity of such cells in the alveoli of the control biopsies. The prognosis for the patients depends on any one or combination of any of the following factors: the pathological changes present in the lungs prior to the extracorporeal circulation, the duration of the cardiopulmonary bypass, the rate of the elimination of the surfactant and finally the ability of the undamaged type-II pneumocytes to step up the synthesis and secretion of the surface acting agent.

Adult↗
PubMedDate not supplied

Lead concentration in soil from a small 15th-century industrial site: occupational and environmental health implications.

Former industrial sites are often reclaimed for new homes and other occupational uses. Such sites may still contain toxic chemicals that could put the health of the community at risk. The persistence of these residual chemicals and their effects on human health must not be underestimated. Hence, there is a need to analyze such sites to ensure that the public health will not be put at risk. It is also essential that the levels of release of heavy metals into the environment be monitored and regulated. In this study the lead (Pb) concentration in soil from a small 15th-century industrial site was determined to assess and evaluate its occupational and environmental health implications. Concentrations of Pb measured by atomic absorption spectroscopy (AAS) and inductively coupled plasma-emission spectroscopy (ICP-AES) techniques were 4,298.755 mg/L (SD 0.316; RSD 0.5%) and 4,300 mg/L (SD 0.3809; RSD 0.8%), respectively, both above the safe limit. It is concluded that reclaiming a disused industrial site without adequate soil analysis and proper remediation would be likely to pose occupational and environmental health risks.

England↗
PubMedDate not supplied

The involvement of serotonin (5-hydroxytryptamine) in photosensitive epilepsy.

Over the last decade, vigorous efforts have been made by neuroscientists to unravel the cellular and molecular basis of photosensitive Epileptogenic activities in the central nervous system (CNS). Many neurotransmitters are implicated in brain activities but the extent to which they participate in these activities needs to be clarified. This review discusses the involvement of serotonin (5-hydroxytryptamine, 5-HT) in photosensitive epilepsy. The biosynthesis, metabolism, and structural and functional distribution of serotonin in the brain, and the role of 5-HT, its precursors, metabolites, receptors, agonists, antagonists, and the enzymes of reaction in photosensitive epileptogenic activity with reference to 5-HT cortical density, are discussed. The effects of biosynthetic and metabolic impairments in the serotonergic system, and the extent to which they contribute to the elicitation of myoclonic phenomena, hallucination, impulsivity, and migraine (HIMM) in photosensitive epilepsy are critically reviewed, and supported by evidence from animal models of photosensitive epilepsy. This evidence is correlated with the clinical findings in human photosensitive epilepsy.

Epilepsies, Myoclonic↗
PubMedDate not supplied

Alcohol dependence: a critical look at the effects of alcohol metabolism.

This paper explores the metabolic consequences of alcohol misuse and identifies the pathophysiological reasons why alcohol, no matter what quantity is taken regularly, is not beneficial for the normal functioning of most body systems. Although moderate ethanol consumption may reduce stress and the risk of coronary heart disease, ethanol also exerts a direct toxicological effect because it interferes with hepatic metabolism and immune functions. Liver transplantation may be necessary for end-stage liver disease in alcoholics. A causal effect between alcohol intake and several cancers has been reported. Both environmental and genetic factors are involved in the susceptibility to alcoholism. An explanation of alcohol dependence as a family disease is introduced to shed light on the magnitude of its collateral effects on the family and on the community as a whole. The adverse effects of alcohol on pregnant women and the fetus are also discussed. To provide awareness of the effectiveness of community efforts, we examined the possible intervention strategies and the role of community care in this regard.

Adult↗
PubMedDate not supplied

Complex interconvertibility of nitrogen oxides (NOX): impact on occupational and environmental health.

Oxides of nitrogen have been implicated in a vast number of environmental and occupational health effects, some of which lack concrete mechanisms. Whereas certain compelling pieces of evidence link a particular nitrogen oxide to a particular adverse health effect, other reports seem to implicate virtually all the oxides in one form of toxic process or the other. Such diversity has probably emerged because each oxide of nitrogen possesses a different oxidation state, in which each form exerts different important levels of biological activity. Most important, each nitrogen oxide readily interconverts into another oxide at a very fast rate. This property of rapid interconvertibility poses problems to researchers in identifying with great confidence the actual oxide of nitrogen that is responsible for a specific occupational and environmental health effect. This paper reviews the complex nature of the nitrogen oxides (represented collectively as NOX) to explore the extent to which their acute or chronic exposure could be associated with toxicity. The nomenclature of the nitrogen oxides is outlined as a necessity for clarity and simplicity in understanding their reactions and interconvertibility and how they affect health. The natural occurrence and sources of occupational and environmental exposures and effects are critically evaluated and analyzed.

Environmental Exposure↗