Response to hormonal treatment and conception rates of Sahiwal cows subjected to fixed time artificial insemination in pastoral dairy systems.

This study aimed at determining factors influencing response of Sahiwal cows/heifers to fixed time artificial insemination protocol in pastoral systems in Kenya. Available cows/heifers were inspected for conformity to Sahiwal breed characteristics, parity, body condition score, and subsequently rectal palpation to determine pregnancy status, ovarian structures, and estimated ovarian diameter. Consequently, these animals were injected with 100 µg of gonadotrophin-releasing hormone. On days 7 and 9, only responsive cows/heifers were injected with 500 µg of cloprostenol and 100 µg of gonadorelin Acetate, respectively. On day 10, animals were inseminated and separated from bulls for 45 days and pregnancy diagnosis done after 90 days. Analysis of variance was performed to determine the effects of production system, parity, and ovarian structures on ovary diameters pre- and post-hormonal treatment. Logistic regression was used fitting a logit function to account for the binomial distribution of conception. Overall, 56.2%, 23.1%, and 20.7% of the animals had follicles (F), corpus luteum (CL), and corpus albicans (CA), respectively, at day 0, and 16.6%, 68.6%, and 14.8%, respectively, at day 7. Human and environmental factors had no influence on conception. Among the animal factors, only the ovarian structures at day 7 had a significant effect on conception. Ovaries with CL at this time were about 6 times significantly more likely to conceive than those with F. For higher conception rates, animals with ovaries with CL should be recruited into the FTAI program as they are significantly more likely to conceive than those with other ovarian structures.

Laboratory safety evaluation of bedinvetmab, a canine anti-nerve growth factor monoclonal antibody, in dogs.

Nerve growth factor (NGF), a critical mediator of nociception, is a novel analgesic therapeutic target. Bedinvetmab, a canine monoclonal antibody (mAb), binds NGF and inhibits its interaction with tropomyosin receptor kinase A (trkA) and p75 neurotrophin receptor (p75NTR) receptors. The objective of three integrated laboratory studies was to demonstrate the safety of bedinvetmab in adult laboratory Beagle dogs. Daily health, veterinary, clinical pathology, systemic exposure, and anti-drug antibody evaluations were performed. Study 1 additionally included electrocardiography, neurologic, and ophthalmic assessments, and radiographic monitoring of joints of the appendicular skeleton. Study 2 evaluated T-lymphocyte-dependent immune function. Study 3 evaluated the safety of short-term concurrent administration of carprofen, a nonsteroidal anti-inflammatory drug (NSAID), with bedinvetmab. Studies 1 and 3 included terminal pathology and histopathology evaluations. Study designs and procedures included directed complementary morphologic and functional evaluations of a literature- and in vitro-based list of potential safety issues related to the NGF signaling pathway and characteristics engineered into this mAb. Screening-level general procedures evaluated effects associated with mAbs that target and inhibit soluble agonist cytokines. There were no treatment-related adverse changes in clinical evaluations, clinical neurological and ophthalmic examinations, joints, immune morphology or function, and no effects of short-term concurrent NSAID usage. Treatment-emergent immunogenicity was not observed. Bedinvetmab (1 mg/kg SC monthly; 3× and 10× dose multiples) was well tolerated in normal laboratory Beagle dogs for 6 months and with 2 weeks' concurrent NSAID administration.

Late production of CXCL8 in ruminant oro-nasal turbinate cells in response to Chlamydia abortus infection.

Chlamydia abortus is an obligate intracellular bacterium that is an important cause of ovine abortion worldwide. There are reports of abortions in cattle, but these are very rare compared to the reported incidence in sheep. The bacterium is transmitted oro-nasally and can establish a sub-clinical infection until pregnancy, when it can invade the placenta and induce an inflammatory cascade leading to placentitis and abortion. Early host-pathogen interactions could explain differential pathogenesis and subsequent disease outcome in ruminant species. In this study, we assessed the ability of sheep and cattle oro-nasal turbinate cells to sense and respond to C. abortus infection. The cells expressed toll like receptor (TLR) 2, TLR4, nucleotide oligomerization domain (NOD) 1 and NOD-like receptor pyrin domain containing 3 (NLRP3) mRNA. In response to C. abortus infection, both ovine and bovine turbinate cells produce CXCL8 mRNA and protein late in the bacterial developmental cycle, but do not produce IL-1ß or TNF-α. The UV-inactivated bacteria did not elicit a CXCL8 response, suggesting that intracellular multiplication of the bacteria is important for activating the signalling pathways. The production of innate immune cytokines from cattle and sheep turbinate cells in response to C. abortus infection was found to be largely similar.

Subclinical nephrotoxicity associated with occupational silica exposure among male Kenyan industrial workers.

OBJECTIVE: To determine early signs of renal injury due to occupational silica exposure. DESIGN: Cross-sectional analytical research. SETTINGS: Kenyatta National Hospital for the referent population and Clayworks ceramics, bricks and tiles factory for the assessment of occupational silica exposure. SUBJECTS: Thirty three non-smoking silica-exposed male industrial workers and 38 non-smoking male referents participated in this study. RESULTS: Silica-exposed males excreted significantly increased levels of U.TP, U.Malb, U.ALP, U.y-GT and U.LDH compared to referent males. Among the silica-exposed males, U.Si negatively correlated significantly with age, U.TP correlated significantly to each of U.ALP and U.LDH. However, no correlation was observed between work duration and U.Si. CONCLUSION: The present study shows that there is associated glomerular and proximal tubular damage among silica exposed workers which is not duration related and is seemingly subclinical and nonprogressive and urinary silica levels appears to be similar in all groups and are not affected by exposure and work duration: the reason for which is unclear.

The morphology of the pecten oculi of the ostrich, Struthio camelus.

The pecten oculi is a structure peculiar to the avian eye. Three morphological types of pecten oculi are recognized: conical type, vaned type and pleated type. The pleated type has been well studied. However, there exists only scanty data on the morphology of the latter two types of pectens. The structure of the vaned type of pecten of the ostrich, Struthio camelus was investigated with light and electron microscope. The pecten of this species consists of a vertical primary lamella that arises from the optic disc and supports 16-19 laterally located secondary lamellae, which run from the base and confluence at the apex. Some of the secondary lamellae give rise to 2 or 3 tertiary lamellae. The lamellae provide a wide surface, which supports 2-3 Layers of blood capillaries. Pigmentation is highest at the distal ends of the secondary and tertiary Lamella where blood capillaries are concentrated and very scanty on the primary and the proximal ends of the secondary lamella where the presence of capillaries is much reduced. In contrast to the capillaries of the pleated pecten, the endothelium of the capillaries in the pecten of the ostrich exhibits very few microvilli. These observations suggest that the morphology of the pecten of the ostrich, a flightless ratite bird is unique to the pleated pecten and is designed to meet the balance between optimal vision and large surface area for blood supply and yet ensuring it is kept firmly erect within the vitreous.

A subset of Cowdria ruminantium genes important for immune recognition and protection.

Cowdria ruminantium causes the tick-borne rickettsial disease of heartwater, which is devastating to livestock production in sub-Saharan Africa. Current diagnosis and control methods are inadequate. We have identified and sequenced a subset of genes encoding recombinant antigens recognized by antibody and peripheral blood mononuclear cells from immune ruminants. The identified genes include many with significant similarity to those of Rickettsia prowazekii, genes predicted to encode different outer membrane proteins and lipoproteins and a gene containing an unusual tandem repeat structure. Evidence is presented for immune protection by recombinant antigens in a mouse model of C. ruminantium infection. These data identify new recombinant antigens for evaluation in vaccines and diagnostic tests to control heartwater.

Gut morphology and morphometry in the epauletted Wahlberg's fruit bat (Epomophorus wahlbergi, Sundevall, 1846).

The morphological adaptations of the fruit bat small intestine to which the high functional efficiency could be related and the possible landmarks delineating the various parts of the gut were examined. The stomach was the carnivorous type with large rugae spanning the entire luminal aspect down to the pyloric sphincter, which was reflected internally as a prominent fold. Externally, the intestine was a continuous tube uninterrupted by any structures. The cranial fifth of the small gut had long, branching and anastomosing villi, which caudally turned to finger-like discrete structures that became rather short and stumpy and diminished at the beginning of the colon. The colon had longitudinal folds that were macroscopically discernible from the mucosal aspect of the opened intestine and that continued into the rectum. The small gut formed 94% of the whole intestinal length, the colon and the rectum taking 4 and 2%, respectively. Ultrastructurally, the enterocyte showed a prominent brush border and the lateral membranes were modified into numerous tortuous interdigitating processes. Adjacent enterocytes were joined by these processes through desmosomes. The processes also participated in pinocytotic fluid uptake from the intercellular spaces with resultant numerous intracellular vacuoles of varied sizes. Solutes absorbed into the cells were probably first passed into the intercellular compartment to create a concentration gradient thus enhancing further absorption into the cell. We conclude that the uniquely elaborate ultrastructure of the enteric epithelium coupled with the vast microvillous surface areas reported elsewhere are partly responsible for the very high absorption rates reported in the fruit bat small intestine.

Morphological analysis of the postnatally developing marsupial lung: The quokka wallaby.

We investigated the events that take place during the postnatal morphogenesis of the lung of the quokka wallaby, Setonix brachyurus, using the light microscope and both the scanning and transmission electron microscopes. The lung of term, newborn babies (joeys) at 3-days of postnatal life was at late canalicular stage and comprised large airways and tubules separated by thick mesenchymal interstitium. The tubules were lined by a low cuboidal epithelium but had few portions with true gas exchange barrier where capillaries came into close contact with squamous type of epithelium. By the fifth day postpartum, the lung entered the early saccular stage characterised by large air sacs, thinner septa, a better developed double capillary system and conversion of the cuboidal epithelium into a squamous one of type I cells interrupted by groups of cuboidal type II cells with lamellar bodies. Transitory respiratory bronchioles were recognisable toward the end of this stage. Formation of secondary septa started by Day 15, dividing the saccules into several generations of smaller air spaces. There were alternating and concurrent periods of tissue proliferation and air space expansion, followed by septal thinning. Alveolization started from about 125 days postpartum when the first burst of small sized air spaces bounded by septa with a single capillary layer were encountered. By Day 180 the process of alveolization was completed with only occasional septa showing a double capillary system and by Day 210 postnatally, the lung resembled that of an adult. For the first time in a mammal, the canalicular stage was encountered postnatally during lung development.

Cerebellar parameters in developing 15 day old rat pups treated with propylthiouracil in comparison with 5 and 24 day old.

OBJECTIVE: To investigate and quantify structural parameters in the developing cerebellum during hypothyroidism in pre and postnatal stages in 15 day old rat pups in comparison with 5 and 24 day old. METHODS: Propylthiouracil (PTU) was fed to rat dams during mating, pregnancy and nursing and their pups in drinking water. Consequently hypothyroxinemia was induced in the dams and the developing foeti during prenatal period and maintained in the dams and pups. The number of treated and control dams was five in each group. The treated and control pups were eight and eleven respectively. The whole cerebellum was dissected out and routinely processed for histological and morphometric analysis. Structural changes in cerebellum were estimated using "design based" stereological methods. The total volume of cerebellum, intracerebellar nuclei and cerebellar compartments were estimated using Cavalieri Principle. Numerical density of cells was estimated using the disector method and the total cell number was then calculated. RESULTS: In the 15 day pups there was significant reduction (P<0.05) in the mean volumes of cerebellum, internal granular layer, molecular layer, cerebellar cortex, mean ratio of the total volume of intracerebellar nuclei to the cerebellar volume and increased mean volume of external granular layer in treated pup group compared with control. The mean volumes of intracerebellar nuclei and white matter and the mean numerical densities and total numbers of neurons and Purkinje cells in intracerebellar nuclei and cerebellum respectively were nearly equal in control and treated groups. Significant increase (P<0.05) in the mean numerical density and total number of glial cells in treated pups compared with control was observed. There was significant decrease (P<0.05) in the mean neuron/neuroglia ratio in the intracerebellar nuclei, mean numerical density and mean total number of granule cells and reduction in the mean ratio of total number of granule/Purkinje cells in the treated group compared with control. The linear regression comparison for the total volume of the intracerebellar nuclei to total volume of the cerebellum in 5, 15 and 24 day control and treated pups and for the total number of glial cells on the total volume of intracerebellar nuclei in the same were significantly different (P<0.05). Total numbers of neurons and glial cells in the intracerebellar nuclei showed peak values in 15 day pups. CONCLUSION: Thus PTU-induced hypothyroidism causes variation in quantitative structural parameters in developing cerebellum and disrupts progressive cellular developmental processes. Maintenance of normal T4 and T3 levels during growth and maturation of cerebellum is absolutely essential.

Monoclonal antibody binding to a surface-exposed epitope on Cowdria ruminantium that is conserved among eight strains.

Monoclonal antibodies (MAb) binding to Cowdria ruminantium elementary bodies (EB) were identified by enzyme-linked immunosorbent assay, and surface binding of one MAb (446.15) to intact EB was determined by immunofluorescence, immunogold labeling, and transmission electron microscopy. MAb 446.15 bound an antigen of approximately 43 kDa in immunoblots of eight geographically distinct strains. The MAb did not react with Ehrlichia canis antigens or uninfected bovine endothelial cell lysate and may be useful in diagnostic assays and vaccine development.

A highly sensitive, non-radioactive assay for T cell activation in cattle: applications in screening for antigens recognised by CD4(+) and CD8(+) T cells.

We describe a highly sensitive, non-radioactive assay for T cell activation, based on the rapid induction of class II MHC expression by constitutively negative bovine endothelial cells, when cultured in the presence of supernatants derived from activated bovine T cells. We demonstrate the effectiveness of this assay in detecting rBoIFNgamma and activation of immune CD4(+) and CD8(+) T cell lines and clones in response to specific antigen and transfected COS-7 cells, respectively. We also demonstrate its utility in identifying purified pathogen fractions that activate immune CD4(+) T cell clones.

Stereological analysis of the cerebellum of 24-day old rats with propylthiouracil-induced hypothyroidism.

OBJECTIVE: To investigate the structural parameters of the developing cerebellum in propylthiouracil (PTU)-induced hypothyroidism during pre and postnatal stages in 24 day old rat pups. METHOD: Hypothyroidism was induced by feeding the breeding dams with PTU in water before and during copulation, pregnancy and lactation and the pups through the dams and ingestion in water. The number of control and treated dams and pups was five for each dam group and twelve and thirteen for pups respectively. The whole cerebellum was dissected out from the pups and processed routinely for histological examination and morphometric analysis. The total volumes of cerebellum, intracerebellar nuclei and cerebellar compartments were estimated by Cavalieri method. The mean numerical densities of neurones and neuroglia in the intracerebellar nuclei and Purkinje, granule and combined stellate and basket cells in cerebellar cortex were estimated using optical disector and the total numbers calculated as the product of the respective numerical densities and reference volumes. RESULTS: The treated dams and pups had relatively lower mean body weights and etraiodothyronine (T4) serum concentrations. The serum Triiodothyronine (T3) was normal and lower in the treated dams and pups respectively. The differences in the respective body weights and dam T4 concentration in treated dams and pups were significant (p<0.05) compared to the control. Morphometric results showed that the mean volumes of cerebellum, intracerebellar nuclei, white matter, internal granular layer, molecular layer and the cerebellar cortex were lower and the differences between the values for each parameter were significant (p<0.05) in the treated pups compared to the control. The mean numerical densities of neurones and neuroglia in the intracerebellar nuclei (Nvne; Nvgl) and the combined stellate and basket cells (Nvsb) in the cerebellar cortex were relatively higher and the mean values for the respective numerical densities of Purkinje and granule cells (Nvpu; Nvgr) were relatively lower in the treated pups compared to the control. On the other hand the treated pups had relatively lower values for the respective total numbers of neurons (Nne), neuroglia (Ngl), Purkinje (Npu), granule (Ngr) and the combined stellate and basket (Nsb) cells compared to the control. The differences between the respective values for Nvne, Nvsb, Npu, and Ngr, were significant (p<0.05). CONCLUSION: These results show that rat pups with PTU-induced hypothyroidism have relatively lower mean values for the structural parameters in the cerebellum when compared to control pups. This confirms that growth and maturation of the cerebellum is dependent on the maintenance of normal T4 and T3 levels, underscores the magnitude of the deviations from the normal and sheds light on possible structural limitations in the cerebellum in cretins.

Comparative parasitological and haematological changes in two breeds of sheep infected with Fasciola gigantica.

Twelve each of Red Masai and Dorper sheep, aged between 6 and 9 months, were acquired from a Fasciola-free area of eastern Kenya. Each breed was divided into two groups of 6. The sheep in one group of each breed were experimentally infected with 400 viable metacercariae of Fasciola gigantica. The other group of 6 sheep of each breed remained as uninfected controls. The animals were monitored regularly for any evidence of disease. Blood samples taken weekly revealed a general reduction in red cell counts and packed cell volume, which was much faster in the infected Dorper sheep than in the Red Masai. This reduction started from the tenth week after infection and persisted to the end of the experiment 18 weeks post infection (PI). The absolute eosinophil counts rose in all the infected animals, but the values were higher among the Dorper than among the Red Masai. Patency occurred at weeks 12 and 13 PI in the Red Masai and Dorpers, respectively, with the latter shedding significantly more fluke eggs. The worm recovery rates were higher among the Dorpers than among the Red Masai, though not significantly so. On the basis of egg counts and clinicopathology, the Dorper sheep were considered to be more susceptible to F. gigantica infections.

A comparison of serum biochemical changes in two breeds of sheep (Red Masai and Dorper) experimentally infected with Fasciola gigantica.

Twelve Red Masai and 12 Dorper sheep aged between 6 and 9 months, were acquired from a fluke-free area and sheep of each breed divided into two equal groups of six. Each animal in one group of each breed was experimentally infected with 400 viable metacercariae of Fasciola gigantica. The other groups acted as uninfected controls. Blood samples were taken at weekly intervals for the determination of serum bilirubin, albumin, and gamma glutamyl transferase levels. Following the establishment of infection, albumin levels declined in both breeds of infected animals without any significant difference between the two breeds. However, serum bilirubin and gamma glutamyl transferase (GGT) in the infected animals were elevated significantly more in the Dorper than in the Red Masai sheep. Based on these findings, it would appear that Dorper sheep are more susceptible to the infection than Red Masai sheep.

Analysis of cellular responses to native and recombinant proteins of Cowdria ruminantium.

The response of PBMC collected from cattle immunized with killed Cowdria to MAP1, MAP1-B, MAP2 and to a lysate of Cowdria was characterized in vitro. CD4+ T lymphocytes responded strongly to Cowdria lysates while B cells and gamma delta T cells proliferated in response to recombinant proteins. Short-term cell lines derived from PBMC using Cowdria lysates were more than 90% CD4+ and did not respond to any of the recombinant proteins. Restimulation of PBMC with MAP1, MAP1-B, and MAP2 proved difficult, and cultures usually stopped proliferating after 2 to 3 weeks. Only one cell line could be generated using MAP1 and it was composed of 85% gamma delta T cells. This study indicates that in animals immunized with killed Cowdria, proteins other than the serologically immunodominant MAP1 and MAP2 are strongly immunogenic for T lymphocytes.

Immunization of cattle by infection with Cowdria ruminantium elicits T lymphocytes that recognize autologous, infected endothelial cells and monocytes.

Peripheral blood mononuclear cells (PBMC) from immune cattle proliferate in the presence of autologous Cowdria ruminantium-infected endothelial cells and monocytes. Endothelial cells required treatment with T-cell growth factors to induce class II major histocompatibility complex expression prior to infection and use as stimulators. Proliferative responses to both infected autologous endothelial cells and monocytes were characterized by expansion of a mixture of CD4+, CD8+, and gammadelta T cells. However, gammadelta T cells dominated following several restimulations. Reverse transcription-PCR analysis of cytokine expression by C. ruminantium-specific T-cell lines and immune PBMC revealed weak interleukin-2 (IL-2), IL-4, and gamma interferon (IFN-gamma) transcripts at 3 to 24 h after stimulation. Strong expression of IFN-gamma, tumor necrosis factor alpha (TNF-alpha), TNF-beta, and IL-2 receptor alpha-chain mRNA was detected in T-cell lines 48 h after antigen stimulation. Supernatants from these T-cell cultures contained IFN-gamma protein. Our findings suggest that in immune cattle a C. ruminantium-specific T-cell response is induced and that infected endothelial cells and monocytes may present C. ruminantium antigens to specific T lymphocytes in vivo during infection and thereby play a role in induction of protective immune responses to the pathogen.

Cellular immune responses of cattle to Cowdria ruminantium.

Peripheral blood mononuclear cells (PBM) from cattle immunised against Cowdria ruminantium infection (Heartwater), proliferated in vitro in the presence of either infected autologous endothelial cells pre-treated with T cell growth factors to induce MHC class II expression, or infected autologous monocytes. Proliferation was not observed in PBM cultured with a soluble extract of the agent, but PBM responded to two recombinant antigens of C. ruminantium, namely a 32 kDa (MAP1) and a 21 kDa antigen (MAP2). We hypothesize that infected endothelial cells and monocytes present Cowdria antigens to specific lymphocytes during infection and thereby play a role in the pathogenesis/immune response to the pathogen.

Effect of propylthiouracil induced hypothyroidism in developing rat cerebellum: comparison of cerebellar parameters in five day old normal and treated rat pups.

The effect of pre and postnatal hypothyroid environment on the development of cerebellum in the rat pups was determined. Four groups of rat dams, namely control, Group I, II and III were treated with propylthiouracil (PTU) in water for different length of time during pregnancy and nursing periods. The pups born from these dam groups were subsequently named after the corresponding dam group, namely control, Group I, II and III. General quantitative results showed that pups from the treated dams had significantly lower (p < 0.05) body weights compared to control pups. Cerebella from five day old pups were taken and structural changes estimated using unbiased "design based" stereological methods, which have made it possible to investigate specific qualities in the organ. The total volumes of cerebellum and intracerebellar nuclei were estimated using Cavalieri Principle. The mean total volume of cerebellum and the mean total volume of intracerebellar nuclei were significantly lower (p < 0.05) in all the pup groups (I, II, III) from the treated dams compared to control pups from the control dams. The cerebellar volume decreased in relation to the duration of treatment. The mean ratio of the total volume of intracerebellar nuclei to volume of cerebellum was significantly increased (p < 0.05) in Group III pups compared to control and Group I pups. The mean numerical density of neurones in the intracerebellar nuclei was nearly equal in all the pup groups except in Group III pups whereby it was increased. The mean total number of neurones in Groups I and II pups was reduced, but did not reach statistical significance. The mean numerical density of neuroglia in the intracerebellar nuclei was nearly the same in all the pup groups, the mean total number of glial cells was significantly reduced (p < 0.05) in Groups I and II pups compared to control and the mean neuron/glial ratio was increased in Group III pups compared to control and other treated groups. Thus, the neuroglia appear to be more sensitive to hypothyroidism than neurons. The above results show that PTU-induced hypothyroidism causes reduction in structural parameters in developing cerebellum and confirm that growth and maturation of the foetal cerebellum is dependent on the maintenance of normal T4 and T3 levels in the pregnant dam and developing pups during pre and postnatal stages of development.

Serum Hanganutziu and Deicher (HD) antibody and total sialic acid levels in hepatoma patients.

A preliminary short follow-up study of Hanganutziu and Deicher (HD) antibody titre and sialic acid levels in sera from 7 patients with hepatoma was carried out. Weekly HD antibody titres were abnormal in 6 patients with titres of 4 of the 6 falling to normal in some weeks. Sialic acids levels, however were abnormal (3.830-6.82mmol/ l) compared to those of 33 normal sera (1.08-2.73 mmol/1) throughout the 8 week screening period. There was a poor correlation between the antibody tires and the sialic acid levels (r<0.50) suggesting that at some stage of malignancy, the tumour was expressing N-glycolylneuraminic acid (Neu5Gc), the epitope of HD antigens as well as shedding into circulation, excess N-acetylneuraminic acid (Neu5Gc). Neu5Gc is a tumor-associated antigen. Measurement of antibodies to this epitope have shown that the antibodies have a potential of offering an alternative method of determining tumor growth and/or metastases. A major follow-up study incorporating information on cancer type, disease stage, therapy and the immnunological status of the patient is called for.