Influence of maternal education on child immunization and stunting in Kenya.

In 2003, the child mortality rate in Kenya was 115/1000 children compared to 88/1000 average for Sub-Saharan African countries. This study sought to determine the effect of maternal education on immunization (n=2,169) and nutritional status (n=5,949) on child's health. Cross-sectional data, Kenya Demographic Health Survey (KDHS)-2003 were used for data analyses. 80% of children were stunted and 49% were immunized. After controlling for confounding, overall, children born to mothers with only a primary education were 2.17 times more likely to be fully immunized compared to those whose mothers lacked any formal education, P<0.001. For nutrition, unadjusted results, children born to mothers with primary education were at 94% lower odds of having stunted growth compared to mothers with no primary education, P<0.01. Policy implications for child health in Kenya should focus on increasing health knowledge among women for better child health outcomes.

Evaluation of risk factors for Alzheimer's disease in elderly east Africans.

A number of biological risk factors have been implicated for Alzheimer's disease (AD). The investigation of prevalence rates of AD in crosscultural populations has much potential in validating these factors. We previously assessed brain amyloid beta (A beta) protein deposition and other lesions associated with AD as possible markers for preclinical AD in elderly nondemented East Africans. In further analysis, we demonstrate that 17-19% of elderly East African subjects without clinical neurological disease exhibited neocortical A beta deposits and minimal neurofibrillary changes at necropsy that was qualitatively and quantitatively similar to that in an age-matched elderly control sample from Cleveland, OH. A beta deposits varied from numerous diffuse to highly localized neuritic plaques and were predominantly reactive for the longer A beta 42 species. In parallel studies, we evaluated another recently implicated factor in AD, the apolipoprotein E genotype. We found relatively high frequencies of the apolipoprotein E-epsilon 4 allele in elderly nondemented East Africans. The frequencies were comparable to those in other African populations but higher than in subjects from developed countries. Our limited study suggests that elderly East Africans acquire cerebral lesions found in AD subjects but the apolipoprotein E-epsilon 4 allele may not be a highly specific factor for the disease among East Africans.

Cerebral amyloid beta protein deposits and other Alzheimer lesions in non-demented elderly east Africans.

There is little knowledge of the existence of Alzheimer disease (AD) or Alzheimer type of dementia in indigenous populations of developing countries. In an effort to evaluate this, we assessed the deposition of amyloid beta (A beta) protein and other lesions associated with AD in brains of elderly East Africans. Brain tissues were examined from 32 subjects, aged 45 to 83 years with no apparent neurological disease, who came to autopsy at two medical Institutions in Nairobi and Dar es Salaam. An age-matched sample from subjects who had died from similar causes in Cleveland was assessed in parallel. Of the 20 samples from Nairobi, 3 (15%) brains exhibited neocortical A beta deposits that varied from numerous diffuse to highly localized compact or neuritic plaques, many of which were also thioflavin S positive. Two of the cases had profound A beta deposition in the prefrontal and temporal cortices and one of these also exhibited moderate to severe cerebral amyloid angiopathy. Similarly, 2 of the 12 samples from Dar es Salaam exhibited diffuse and compact A beta deposits that were also predominantly reactive for the longer A beta 42 species compared to A beta 40. We also noted that A beta plaques were variably immunoreactive for amyloid associated proteins, apolipoprotein E, serum amyloid P and complement C3. Tau protein reactive neurofibrillary tangles (NFT) were also evident in the hippocampus of 4 subjects. By comparison, 4 (20%) of the 20 samples from randomly selected autopsies performed in Cleveland showed A beta deposits within diffuse and compact parenchymal plaques and the vasculature. These observations suggest A beta deposition and some NFT in brains of non-demented East Africans are qualitatively and quantitatively similar to that in age-matched elderly controls from Cleveland. While our small scale study does not document similar prevalence rates of preclinical AD, it suggests that elderly East Africans are unlikely to escape AD as it is known in developed countries.

Effects of exercise training on responses of peripheral and visceral arteries in swine.

Blood flow to skeletal muscle during exercise is greater in the trained state. We hypothesized that intrinsic vasomotor reactivity of arteries to active muscle during training bouts would be altered to favor a relative vasodilation after training. To test this hypothesis, miniature swine were pen confined (Sed; n = 30) or treadmill trained for 5 days/wk over 16-20 wk (Trn; n = 32). Efficacy of training was indicated by myocardial hypertrophy (4.84 +/- 0.11 and 5.81 +/- 0.12 g/kg body wt for Sed and Trn, respectively, P < 0.0005), training bradycardia at several submaximal running speeds of a maximal exercise test, increased running time to exhaustion (26 +/- 1 and 35 +/- 1 min for Sed and Trn, respectively, P < 0.0005), and increased oxidative capacities of several locomotory skeletal muscles. Segments of femoral, brachial, mesenteric, renal, and hepatic arteries were isolated from Sed and Trn swine. Isometric contractile and relaxation properties of vascular rings cut from these segments were determined in vitro. Contractile responses to KCl and norepinephrine (NE) were determined, as were relaxation responses to sodium nitroprusside and adenosine, agents acting directly on vascular smooth muscle, and the endothelium-dependent agents bradykinin and the calcium ionophore A-23187. Responses to vasocontractile and vasorelaxation agents were not different between Sed and Trn swine for vessels serving active muscles (i.e., femoral, brachial). On the other hand, renal arterial rings from Trn swine exhibited lesser contractile responses than those from Sed swine across a range of NE concentrations (P < 0.05) and approximately 25% less maximal contractile response to NE (32.7 +/- 2.6 and 24.2 +/- 2.1 g for Sed and Trn, respectively, P < 0.01). Responses of other vessels serving viscera (i.e., mesenteric, hepatic) were unchanged with training. These data indicate that vasomotor reactivity of porcine conduit-type arteries generally does not change with exercise training. An exception is the lesser contractile response to NE in renal artery, which could permit better preservation of renal blood flow during acute exercise in trained animals.

Studies on the haemolytic complement of the dromedary camel (Camelus dromedarius). II. Alternate complement pathway haemolytic activity in serum.

Fresh camel serum caused lysis of unsensitised red blood cells (RBC) of chicken, rabbit and guinea pig. Homologous RBC were resistant to lysis. There was only minimal lysis of goat, sheep, rat and cattle RBC. Lysis of heterologous RBC was attributed to the presence of alternate complement activity (ACP) in the serum as adsorption with respective RBC and addition of 10 mM ethylene glycol-bistetraacetate (EGTA) in the SVBS diluent did not abrogate the haemolytic activity. Guinea pig RBC were the most sensitive to lysis, giving a mean ACP activity of 41.5 +/- 1.8 CH50 units ml-1. Clotting, followed by storing of blood between 0 and 37 degrees C for 1 h did not significantly affect ACP activity. However, considerable activity was lost when blood was clotted and stored at 44 degrees C for 1 h, or when serum was kept at 4 degrees C for 24 h. Treatment with zymosan, or incubation at 56 degrees C for 30 min inhibited ACP activity. Maximum ACP activity occurred in the presence of 8 mM Mg2+ in the SVBS-EGTA diluent, at pH 7.3 and incubation time of 2 h at 37 degrees C. Levels of ACP activity were determined in 79 healthy camels of different age groups, ranging from 3 months to 15 years. Calves between 3 months and 1 year of age had higher ACP activity than camels in the age group of 5 years and above. Highest mean ACP activity of 89 +/- 7.9 CH50 units ml-1 were recorded in 1-5 year old camels (P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on the haemolytic complement of the dromedary camel (Camelus dromedarius). I. Classical pathway haemolytic activity in serum.

Classical pathway haemolytic complement (CPHC) of the dromedary was assayed under standardised conditions. A total of 14 indicator systems of red blood cells (RBC) and haemolysins were investigated. Highest CH50 titre was obtained with rabbit RBC sensitised with goat haemolysin. Among the factors investigated were: ionic strength, Mg2+, Ca2+, ethylenediaminetetraacetic acid (EDTA) concentration, pH, incubation time and temperature. The standard system of titrating the HC levels consisted of rabbit RBC sensitised with goat haemolysin, sucrose veronal buffer (SVBS) pH 7.4, ionic strength 0.14 M and Ca2+ and Mg2+ concentrations of 4.0 x 10(-4) M and 1 x 10(-3) M, respectively. Incubation at 37 degrees C for 120 min gave the highest HC activity. Using these standardised conditions HC levels were determined in 79 camels aged between 3 months and 15 years. Highest mean HC value of 873 +/- 26.6 CH50 units ml-1 were recorded in the age group of 1-5 year old camels and the lowest mean HC value of 598 +/- 120.8 CH50 units ml-1 in the age group of 10-15 year old camels. Adult males in the age group 5-10 years had significantly higher mean HC levels than their female counterparts (P < 0.0001).

Elastin and mechanoreceptor mechanisms with special reference to the mammalian carotid sinus.

Light microscopic studies reveal that the carotid baroreceptor region in mammals, located at the origin of the internal carotid artery, has a preponderantly elastic structure and a thick tunica adventitia. Electron microscopy discloses the presence of sensory nerve endings within the parts of the tunica adventitia adjoining the preponderantly elastic zone of the internal carotid artery. Bundles of collagen fibres in the tunica adventitia form convolutions or whorls around the nerve terminals and often terminate on the surface of the elastic fibres or into the basement membranes of the neuronal profiles. It is concluded that the large content of elastic tissue in the tunica media of the baroreceptor region renders the vessel wall highly distensible to intraluminal pressure changes, and thereby facilitates transmission of the stimulus intensity to sensory nerve terminals. However, a change in the geometrical configuration of the bundles of collagen under the influence of elastic fibres may provide a better insight into the mechanisms of distortion of the baroreceptors related to and/or in contact with collagen fibres. In support of this is the demonstration of contact sites between collagen and elastic fibres.

Evaluation of the in vitro transformation technique to distinguish Trypanosoma evansi from cyclically transmitted Trypanozoon stocks.

In order to initiate transformation into procyclic forms, bloodstream trypanosomes, were transferred to semi-defined medium at 27 degrees C. All stocks previously classified as Trypanosoma brucei rhodesiense, T.b. gambiense and T.b. brucei transformed into procyclic forms. None of the 31 characterized T. evansi stocks transformed into procyclic forms, but died between day 4 and day 6 in culture. On the other hand, 3 out of 64 stocks of monomorphic brucei subgroup field isolates from camels transformed into procyclic forms, confirming the existence of T.b. brucei infection in camels kept close to tsetse belts.

Electron microscopic structure and innervation of the carotid baroreceptor region in the rock hyrax (Procavia capensis).

Semi-thin plastic sections reveal that the carotid baroreceptor region in the rock hyrax comprising the origin of the internal carotid artery has a preponderantly elastic structure and a thick tunica adventitia. In contrast, the common carotid artery has a musculoelastic structure, whereas the cranial segment of the internal carotid artery (immediately distal to the baroreceptor areas) shows the features of a muscular artery. Electron microscopy discloses the presence of sensory nerve endings within the parts of the tunica adventitia adjoining the preponderantly elastic zone of the internal carotid artery. These nerve endings are characterized by varicose regions containing a large quantity of mitochondria. Bundles of collagen fibers in the tunica adventitia form convolutions or whorls around the nerve terminals and often terminate on the surface of the elastic fibers or into the basement membranes of the neuronal profiles. The large content of elastic tissue in the tunica media of the baroreceptor region may render the vessel wall highly distensible to intraluminal pressure changes. This, in turn, would facilitate the transmission of the stimulus intensity to the sensory nerve terminals located in the tunica adventitia. It is suggested that the stretching of elastic fibers may form the main mechanical event leading to the distortion of the associated nerve terminals. However, a change in the geometrical configuration of the bundles of collagen under the influence of the elastic fibers may provide a better insight into the mechanisms of distortion of the baroreceptors related to and/or in contact with collagen fibers.

The structural organization and adrenergic innervation of the carotid arterial system of the giraffe (Giraffa camelopardalis).

The sympathetic innervation of the giraffe (Giraffa camelopardalis) carotid arterial system is described in this study using the sucrose-potassium phosphate-glyoxylic acid (SPG) method. The brachiocephalic and bicarotid trunks showed a paucity of sympathetic innervation. Smooth muscle nests observed in the outer layers of the tunica media in these arteries revealed a rich network of sympathetic nerve fibres. The common carotid artery showed numerous sympathetic nerve fibres particularly in the outer muscular zone of the tunica media. The internal maxillary, ramus anastomoticus, and arteria anastomotica also revealed a rich sympathetic innervation and a deep penetration of the nerve fibres into the tunica media. It is suggested that the rich sympathetic innervation of the giraffe carotid arteries maintains a basal tonic state in the smooth muscle in the tunica media. This, in turn, may enable the animal to maintain a relatively high rate of blood flow in the carotid arteries in diastole despite the pressure run-off. It is further suggested that the muscular structure and dense sympathetic innervation of the internal maxillary and its branches to the carotid rete mirabile provide the animal with an array of mechanisms to modulate its cranial circulation particularly when it bends its head to drink.

Structure and sympathetic innervation of the intracranial arteries in the giraffe (Giraffa camelopardalis).

Fluorescence histochemistry discloses that the carotid rete mirabile in the giraffe has a poor sympathetic innervation. In contrast, the efferent artery of the rete (internal carotid artery) and the cerebral arteries show moderate sympathetic innervation. A certain degree of regional variability was noted in which the rostral arteries (anterior and middle cerebral) receive more sympathetic nerves than the caudal (posterior communicating and basilar) arteries. The sympathetic nerves on the giraffe cerebral vessels may constitute part of a host of mechanisms by which regional blood flow to the brain is regulated. Conversely, the paucity of sympathetic innervation of the carotid rete mirabile may indicate that this structure does not play an active role in vasoconstrictor responses during postural changes of the head.

Sympathetic innervation of the hindlimb arterial system in the giraffe (Giraffa camelopardalis).

We report the distribution of sympathetic nerves in the hindlimb arterial system of the giraffe based on the histochemical demonstration of monoamines by the sucrose-potassium phosphate-glyoxylic acid method. It is noted that the hindlimb arterial system shows regional variations in its sympathetic innervation with regard to the density and the penetration of the nerves into the tunica media not hitherto described. The femoral and popliteal arteries showed a paucity of sympathetic innervation. Distally the dorsal pedal and great metatarsal arteries showed sparse sympathetic innervation characterized by a tendency toward exclusion of the nerves toward the outer layers of the tunica media. In contrast, the anterior (cranial) tibial artery in the leg revealed a relatively rich pattern of sympathetic innervation and a greater penetration of the nerves into the tunica media. The latter part of the arterial system showed a marked thickening of the tunica media and luminal narrowing, thus suggesting a "sphincteric" function. It is conceivable that this sphincter subserves a dual function, namely, to modulate blood flow to the distal parts of the limbs, and secondly to channel blood to the thigh and crural musculature. Pertinent to this is the fact that the presumptive sphincter occurs immediately after the crural muscular branches are given off.

Segmental variations in the elastic fiber content of the lateral costotransverse ligaments in the vervet monkey (Cercopithecus pygerythrus aethiops).

The segmental and zonal variations in the quantitative relationships between elastic and collagen fibers within the lateral costotransverse ligaments have been investigated in the vervet monkey. The lateral costotransverse ligaments of the caudal segments have a largely elastic structure in contrast to those of the cranial segments, which are characteristically collagenous. In the transitional zone extending from the 4th through to the 6th costotransverse joints, the lateral costotransverse ligaments show a zonal differentiation into a superficial collagenous portion and a deep elastic portion. It is noted that the craniocaudal structural differentiation in the lateral costotransverse ligaments corresponds with similar changes in the vertebral ligaments in that the ligamenta flava gradually extend into the interspinous spaces from the 1st thoracic vertebra (T1) so that at T5 the ligaments occupy 50% of the interspinous space and at T7 the elastic fibers almost completely replace the interspinous ligament. Functionally, however, the regional differences in the elastic fiber content of the lateral costotransverse ligament may have no collateral relationship with the morphology of the ligamenta flava, but are conditioned by movements of the ribs. Whereas movements of the upper six joints are limited by virtue of the configuration of their articular surfaces, which are reciprocally curved, on the 7th to 10th joints the articular facets are almost flat and, therefore, allow considerable movements between the ribs and the corresponding transverse processes.

Structural organization of the vertebral artery in the giraffe (Giraffa camelopardalis).

Vertebral arteries in the giraffe were removed and their structural organization was studied with light microscopy. It has been shown that the caudal segment of the vertebral artery extending to the level of the seventh cervical vertebra has a largely elastic structure, while the cranial segment has a muscular structure. The transition of the arterial wall normally occurs between the seventh and fifth cervical vertebral levels, and involves diminution of elastic tissue in the luminal portion of the tunica media and simultaneous increase of the smooth muscle content. The smooth muscle cells in the cranial portion show a clustered arrangement consisting of several smooth muscle fibres. The individual clusters are separated by connective tissue septa from which finer strands extend to surround individual muscle fibres. It is suggested that the vertebral and carotid arteries though found in the neck have a different structural organization, which, in turn, may imply that the two blood vessels are subjected to different haemodynamic demands. The findings of this study therefore render further support to the statement that the largely muscular structure of the common carotid artery in the giraffe may be related to the unique cerebral haemodynamics of this animal, rather than being a common feature of the blood vessels situated in the neck. A corollary to this suggestion is the fact that, in the giraffe, as in most other Artiodactyls, the vertebral blood does not participate in the supply of cephalic structures because it is confined to the cervical region by the pressure barrier in the carotid-vertebral anastomosis.

The structural and functional organization of the connective tissue in the human foot with reference to the histomorphology of the elastic fibre system.

The structural organization of the connective tissue system has been studied in the human foot using routine light microscopic methods. It has been demonstrated that an intriguing and delicate anatomical arrangement is present in the tissue components as shown by the zonal distribution of collagen fibres, elastic fibres and adipose tissue. Collagen fibres are prevalent in the reticular dermis of the plantar skin, in the septum dividing the subcutis into superficial and deep strata and in the plantar aponeurosis. Elastic fibres occur largely in the papillary dermis of the plantar skin where they form a subepidermal elastic plexus, as well as in the septal framework of the subcutaneous tissue and in close association with the sweat ducts. It is proposed that elastic fibres modulate the distensibility of the subcutaneous tissue when subjected to compressive stresses and its return to normal resting tensile state, while collagen fibres provide rigid constraints that limit over distension of the subcutis as well as the dermis and thereby tether the skin to the plantar aponeurosis.

Adrenergic innervation of the tunica media in the saphenous artery of the fetal and newborn guinea-pig.

Previous studies have demonstrated that adrenergic nerves are located in the medial-adventitial border of the muscular arteries. Observations made in this study have revealed that adrenergic nerves penetrate into the outer medial layer of the saphenous artery in fetal and newborn guinea-pigs, while in the adult these nerves are located in the medial-adventitial border. It is proposed that the adrenergic nerves located in the tunica media may have a trophic effect on the medial smooth muscle. It is further suggested that the final refinement of the dual control system of arterial walls, by nerves and circulating catecholamines, involves exclusion of adrenergic nerves from the tunica media.

Observations on the structure and innervation of the presumptive carotid sinus area in the giraffe (Giraffa camelopardalis).

The tunica media of the giraffe carotid artery is characterised by a predominantly muscular structure, except for a small area at the origins of the occipital and the vestigal internal carotid arteries. The latter has a preponderantly elastic structure and corresponds in extent to the parts of the carotid arterial wall innervated by a branch of the glossopharyngeal nerve. Sensory nerve terminals, characterised by an abundance of mitochondria, are found in the deeper parts of the adventitia bordering the elastic zone. It is concluded that the elastic zone at the cranial portion of the carotid arterial system in the giraffe constitutes the equivalent of a carotid sinus. It is further suggested that the preponderance of elastic tissue in this area is a morphological adaptation of the arterial wall to a baroreceptor function. Pertinent to this suggestion is the demonstration of a close structural relationship between the sensory nerve endings and the elastic fibres.

Some histological aspects of the palmar digital pads in the vervet monkey.

The structural organisation of the digital touch pads has been investigated in the vervet monkey (Cercopithecus pygerythrus) by light microscopy. It has been demonstrated that the subcutaneous tissue of the terminal digital pad consists of a highly organised septal framework containing large amounts of elastic fibres, with adipose tissue sweat gland compartments lying between the connective tissue septa. It is suggested that the presence of elastic fibres in the septal framework of the terminal digital pad is an important factor in accomplishing an even more supple response to prehensile and tactile activities of the hand.

Structural evidence for insertion of collagen fibres to smooth muscle cells in the carotid arterial system of the giraffe (Giraffa camelopardalis).

Previous anatomical studies have failed to resolve the question relating to whether or not collagen fibers, like elastic fibres, are attached to smooth muscle cells in the arterial wall. The current ultrastructural study demonstrates the insertion of collagen fibres to the sarcolemmal dark areas in the smooth muscle cells of the carotid arterial system of the giraffe. It is concluded, therefore, that this morphological linkage between collagen and smooth muscle cells may facilitate transmission of the force of contraction between the cells and to the surrounding connective tissue framework since the myofilaments appear to be spatially placed in series with the extracellular collagen fibres at the sarcolemmal dark areas.