Browsing by Author "Adjenti, S.K."
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Item Development of Transverse Tubular Systems (T-Tubules) In the Hamster (Mesocricetus Auratus) Myocardium(University of Ghana, 2003-01) Adjenti, S.K.; Ayettey, A.S.; Tagoe, C.N.B.; Dennis, E.; University of Ghana, College of Health Sciences, School of Biomedical and Allied Health Sciences, Department of AnatomyWith the aid of an electron microscope the development of transverse tubules (T-tubules or system) was studied in pre- and post-natal hamsters (Mesocricetus auratus) labelled with horse radish peroxidase (HRP). Thin sections (70-90 nm) and semi-thin sections (800-1000 nm) were cut using an ultramicrotome and examined under an electron microscope. No evidence of T-tubules was observed during the pre-natal and first week in neonatal stages of development when myocytes were characterised by large cytoplasmic spaces with few and partially developed but functioning myofibrils. Between seven and fourteen days of postnatal life, myofibrils developed rapidly and the A-and I-bands became more distinct. By the seventh day, shallow indentations of the sarcolemma at the Z-line regions appeared, representing the early beginnings of the T-system. Wide T-tubule invaginations of the sarcolemma with cross-sectional diameter of 200-205 nm began to appear in right and left ventricular myocytes by the twenty-first day of post-natal life in some Z-line regions of myofibrils. At this stage also, myofibrils had adopted adult forms, with well organised cross-striations. Mitochondria were also well developed, occupying the spaces between rows of myofibrils. This study supports the view that T-tubules are primarily adapted for homeostatic functions of the mammalian cardiac myocytes, improving efficiency of transport of metabolic substrates and products, and that they are not for excitation-contraction coupling as presumed by some workers. It also shows that the wide T-system observed in the studies of myocytes of an adult hamster is pre-determined, as this feature is noticeable as early as the third week of post-natal development, coinciding with maturation of the myofibrils for active adult life.Item Development of Transverse Tubular Systems (T-Tubules) in the Hamster {Mesocricetus Auratus) Myocardium.(University of Ghana, 2003-01) Adjenti, S.K.; Ayettey A.S.; Tagoe C.N.B.; Dennis E.; University of Ghana, College of Health Sciences, School of Biomedical and Allied Health Sciences, Department of Anatomy.With the aid of an electron microscope the development of transverse tubules (T-tubules or system) was studied in pre- and post-natal hamsters (Mesocricetus auratus) labelled with horse radish peroxidase (HRP). Thin sections (70-90 nm) and semi-thin sections (800-1000 nm) were cut using an ultramicrotome and examined under an electron microscope. No evidence of T-tubules was observed during the pre-natal and first week in neonatal stages of development when myocytes were characterised by large cytoplasmic spaces with few and partially developed but functioning myofibrils. Between seven and fourteen days of postnatal life, myofibrils developed rapidly and the A-and I-bands became more distinct. By the seventh day, shallow indentations of the sarcolemma at the Z-line regions appeared, representing the early beginnings of the T-system. Wide T-tubule invaginations of the sarcolemma with cross-sectional diameter of 200-205 nm began to appear in right and left ventricular myocytes by the twenty-first day of post-natal life in some Z-line regions of myofibrils. At this stage also, myofibrils had adopted adult forms, with well organised cross-striations. Mitochondria were also well developed, occupying the spaces between rows of myofibrils. University of Ghana http://ugspace.ug.edu.gh This study supports the view that T-tubules are primarily adapted for homeostatic functions of the mammalian cardiac myocytes, improving efficiency of transport of metabolic substrates and products, and that they are not for excitationcontraction coupling as presumed by some workers. It also shows that the wide T-system observed in the studies of myocytes of an adult hamster is pre-determined, as this feature is noticeable as early as the third week of post-natal development, coinciding with maturation of the myofibrils for active adult life.Item Microscopic CharacteristicsOf Scalp Hair Subjected To Cultural Styling Methods In Ghanaian African Females(Clinical, Cosmetic and Investigational Dermatology, 2019-11-18) Essel, E.A.; Ahenkorah, J.; Blay, R.M.; Adjenti, S.K.; Adutwum- Ofosu, K.K.; Hottor, B.A.; Addai, F.K.Purpose: To provide data for forensic use and provoke ideas to preserve shaft integrity, we studied microstructural alterations of female scalp hair subjected to Ghanaian cultural styling methods. Hence, topographical features of female hairs styled by braiding/weaving, and chemical relaxation sampled from five different scalp regions were assessed and compared with natural (Afro) hair. Subjects and methods: Ninety-six indigenous Ghanaian females volunteered 480 hairs, which were analyzed by light microscopy.Hairs were plucked using a pair of cosmetologist’s tweezers from frontal, left temporal, right temporal, vertex, and occipital regions of the scalp. Hairs were categorized by their grooming styles as Afro (natural-unstyled), natural-styled (weaved/braided), and chemically relaxed. These were studied according to shaft/medulla dimensions and conventional cuticular scale features, and comparisons were made between styling procedures and scalp regions. Results: Chemically styled hair had the widest shaft diameter, but the lowest incidence of continuous medullation. Medullary diameter and index increased from chemically relaxed, natural-styled, to Afro hair. A positive but modest correlation between shaft and medullary diameters existed for Afro (r = 0.320, p = 0.011) and natural-styled hairs (r = 0.235, p = 0.022) but not chemically relaxed hair (r = 0.122, p = 0.2). Scale margins were predominantly smooth in Afro hair, crenate in natural-styled hair, and rippled in chemically relaxed hair. With respect to scalp regions, hair shaft diameter was widest in vertex hair and smallest in right temporal hair in all styling methods. Conclusion: Medulla was thickest in Afro hair, which also exhibited a correlation with shaft diameter in conformity with the published data. Chemically relaxed hairs did not exhibit these characteristics, which affirm altered morphology. Research on how chemicals affect these changes should help find antidote. The dimensional variations of hairs from different scalp regions are instructive for both cosmetic and forensic examination of hairs.Item Natural cocoa inhibits maternal hypercholesterolaemia-induced atherogenesis in rabbit pups.(Cardiovascular journal of Africa, 2019-04-16) Blay, R.M.; Adjenti, S.K.; Adutwum-Ofosu, K.K.; Hottor, B.A.; Ahenkorah, J.; Arko-Boham, B.; Addai, F.K.Atherosclerosis begins during foetal development and is enhanced by maternal hypercholesterolaemia during pregnancy. This study assessed the effect of natural cocoa on atherosclerosis in offspring conceived in maternal hypercholesterolaemia. Female rabbits were fed a cholesterol-enriched diet for two weeks and hypercholesterolaemia was confirmed, after which they were crossed with normocholesterolaemic males. One group of hypercholesterolaemic mothers (HCC) received natural cocoa powder (NCP) in their drinking water, whereas the other group (HC) received only water. Histological analysis of three segments of the aorta (arch, thoracic and abdominal) from offspring of both groups was compared with a control group (NC). Intima-media thickness of the aortic arch in offspring born to hypercholesterolaemic rabbits (HC: 146 µm) was higher compared to HCC (99 µm) and control rabbits (58.5 µm). All the sections from the aortic arch of the HC group had atherosclerotic lesions while none of the sections of the aortic arch from the NC and HCC groups had lesions present. Inferentially, regular and voluntary consumption of NCP during pregnancy may inhibit aortic atherogenesis in offspring of hypercholesterolaemic mothers.