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Biomedical subjects

C O Njoku

Publications and source records attributed to C O Njoku.

At least 19 recordsLinked to original sources
PubMed2004

Experimental trypanosomiasis in Yankasa ewes: the body weight response.

Sleeping sickness (African Trypanosomasis) is an anthropozoonosis transmitted primarily by the tsetse fly. It is associated with a host of clinical indices ranging from fever, aneamia and anorexia to reproductive failures in man and his domestic animals. The main objective of this study is to appraise the responsiveness of the body weight as a clinical indicator of sleeping sickness in experimentally infected Yankasa ewes. Twelve mature Yankasa sheep (6 infected and 6 control ewes) were used in this study. Weekly body weights and daily rectal temperature were taken while blood samples for haematology were collected twice a week from all animals before and after the experimental infection. Undulating parasitaemia was observed, two days post infection and was sustained through out the study period of about fifty days in all the infected ewes. Decreased body weight was found to be very prominent in the infected animals. All the infected ewes progressively lost weight during the experiment with a decrease of about 17.9% of the original weights while the control ewes had increased by 4.2% at the end of the study period. The body weight is therefore a very sensitive parameter in the surveillance and management of Trypanosome infections especially in Yankasa ewes as experimental animal models.

Anemia↗
PubMed1993

Study of efficacy of Lamstreptocide A & B on cases of dermatophilosis within the Caribbean.

The efficacy of Lamstreptocide A & B was studied on 9 natural cases of bovine and caprine dermatophilosis in 8 different farms in St. Kitts, employing standard histopathologic and bacteriological methods. The lesions of 5 of the treated cases were dried-up, and there was marked peeling-off of scabs of a severely affected case exposing erythematous underlying tissue, at 3 weeks post-application of the product. Apart from 3 mild cases which were not available for follow-up studies and which were reported to have recovered, there was no outright recovery of the 5 animals after treatment at 3 weeks, and even after a second application of the product. An in vitro sensitivity test of the product revealed a slowing down of growth of Dermatophilus congolensis at concentrations in excess of 1% by agar-streak method. However, there was no inhibition of growth of the bacterium by an agar-impregnated sensitivity method.

Actinomycetales Infections↗
PubMed1993

Screening of "Kargasok tea". IV: Studies of pathological effects in BALB/C mice and Wistar rats.

Forty-eight BALB/C mice (30 males, 18 females) and 18 male Wistar rats were given Kargasok tea in their drinking water. Zero, 15, 25, 50, 75 or 100% concentrations were administered to mice for 2 or 8 w while the rats were given 0, 15 or 50% concentrations of the beverage for 12 w. Neither the mice nor rat's organ/body weight ratios were significantly affected by treatment. Rats receiving 15 or 50% concentrations of the tea had nephropathy and non-suppurative necrosis of the duodenum, pancreas and intestine. No significant microscopic lesions were found in any treated mice even when given 100% concentration of the tea. These findings suggest species variation in susceptibility to toxicity from the tea. The tea may be a cause of renal failure, diabetes mellitus and malabsorption syndrome and may not be safe for human or animal consumption.

Animals↗
PubMed1992

Adrenal and thyroid dysfunctions in experimental Trypanosoma congolense infection in cattle.

Severe pathological changes were observed in the adrenal and thyroid glands of Zebu (Bos indicus) heifers infected with Trypanosoma congolense. In the adrenal glands, severe inflammatory changes characterised by mononuclear cellular infiltration in the subcapsular areas, zona glomerulosa, zona fasciculata and zona reticularis were observed. In addition, there were hyperaemia, haemorrhage and hyperplasia resulting in increased adrenal weight in the two heifers slaughtered on Days 50 and 70 post-infection (p.i.). In the medullary areas of these two heifers, there was only mononuclear cellular infiltration. In the two heifers slaughtered on Day 113, localised mononuclear cellular infiltration was observed in addition to cortical cell depletion and fibrosis, resulting in reduced adrenal weight when compared with the controls. In the thyroid glands of the infected heifers, gross enlargement of the follicles filled with pale staining colloids were observed in association with squamous metaplasia of the follicular epithelium and fibroplasia. Serum cortisol concentrations showed an appreciable but non-significant increase (P less than 0.05) between Weeks 2 and 6 p.i. in the infected heifers (5.6 +/- 0.86 ng ml-1 vs. 4.4 +/- 0.34 ng ml-1) when compared with the uninfected controls or the pre-infection level. Thereafter, cortisol levels declined though non-significantly throughout the rest of the study. However, there was a steady increase towards normal levels from Week 12 p.i. until the end of the experiment. Changes in the basal serum concentrations of thyroxine (T4) were also measured weekly. There was a progressive decrease in the levels of T4 from the third until the 11th week p.i., when the decrease became significant (P less than 0.05) and remained so until the 16th week when the experiment ended.

Adrenal Glands↗
PubMed1991

In vitro magnesium- and calcium-induced sialidase activity in caprine intestinal mucosa cells.

Sialidase activity identical to 0.0196 mg per ml of liberated sialic acids (2.11 Units) was detected in small intestinal contents of goats. Mg++ and Ca++ induced in vitro detection in mucosa cells of both small and large intestines. Magnesium alone induced sialidase activities identical to 0.0128 mg per ml of liberated sialic acids (1.38 Units) and 0.0166 mg per ml (1.79 Units) in small and large intestinal mucosal cells, respectively. Mg++ and Ca++ together induced higher sialidase activities identical to 0.0191 mg per ml (2.06 Units) and 0.0194 mg per ml (2.09 Units) in small and large intestinal mucosal cells, respectively. The enzyme activity was slightly higher in large than in small intestinal mucosal cells. The results are discussed in relation to control of African animal trypanosomiasis.

Animals↗
PubMed1991

Comparative studies of gastrointestinal helminths of poultry in Zaria, Nigeria.

Two-hundred and ten digestive tracts of local chickens reared in and around Zaria, Northern Nigeria, under the extensive native free range system of management and 203 digestive tracts of exotic chickens raised under the intensive system of management were examined for parasites. Two hundred and one (95.7%) of the local chickens were infected and 24 (11.8%) of the exotic chickens also. Among the local chickens, 12 species of nematodes and 7 species of cestodes were recovered. Only one nematode and one cestode species were recovered from the exotic chickens. The prevalence of helminth infections between local and exotic chickens was significantly different at 1%.

Animals↗
PubMed1990

Elevation of morphological abnormalities of spermatozoa in the semen of Zebu bulls consequent to Trypanosoma vivax and Trypanosoma congolense infections.

Twenty-four Zebu bulls were used in a 12-wk long study. Eight bulls were infected with T. vivax , eight others with T. congolense and eight bulls served as controls. All the infected bulls developed chronic trypanosomiasis. Mean percentage base-line values prior to infection for acrosomal, sperm-head, detached heads, proximal cytoplasmic droplets, distal cytoplasmic droplets, sperm-tail, midpiece and total sperm morphological abnormalities ranged between 0.1+/-0.1 for acrosomal and 8.7+/-3.4 for total morphological abnormalities in the semen of the bulls. These values were very low and within the range of those for fertile bulls. Following infection, there was a progressive increase in the mean values of all the abnormalities. Peak percentage mean values recorded for total sperm morphological abnormalities in the course of the investigation in the bulls infected with T. vivax and T. congolense and in the controls were 95+/-7.2, 100+/-0 and 7.9+/-5.0, respectively. Mean percentage values throughout the duration of the investigation for control bulls were low and within the normal range for fertile bulls. These values differed (P<0.001) from the elevated values of the infected bulls. The results indicate that trypanosomiasis due to either T. vivax or T. congolense infections can cause a marked increase in morphological abnormalities of spermatozoa which can, in turn reduce the fertility of breeding bulls.

Journal Article↗
PubMed1990

Comparative haematological changes following Trypanosoma vivax and T. congolense infections in Zebu bulls.

A comparative study of haematological changes subsequent to Trypanosoma vivax and Trypanosoma congolense infections was carried out using 24 Zebu bulls during a period of 12 weeks. Eight bulls were infected with T. vivax, another eight with T. congolense and eight served as controls. Infected bulls developed chronic trypanosomiasis which was characterized by many clinical manifestations including intermittent pyrexia. Elevated rectal temperatures of up to 105 and 106 degrees F were recorded, respectively, in all bulls infected with T. vivax or T. congolense. Mean parasitaemia was higher and more chronic in T. congolense-infected bulls and ranged between means of 0 and 3.06 in all infected bulls. There was a slight and transient drop in packed cell volume (PCV) of T. vivax-infected bulls as against a marked and more chronic drop in T. congolense-infected bulls. Mean PCV of T. vivax- and T. congolense-infected bulls and controls ranged between 28 and 38, 17 and 38, and 31 and 38%, respectively. Haemoglobin (Hb) concentrations also decreased in infected bulls. The decrease was greater and more chronic in the T. congolense-infected bulls. Values ranged between means of 10.47 and 13.84, 5.44 and 14.16, and 10.24 and 14.12 g dl-1 in T. vivax- and T. congolense-infected and control bulls, respectively. Total plasma proteins also decreased in infected bulls; this was more marked in the T. congolense-infected group. Values for T. vivax-infected, T. congolense-infected and control bulls ranged between means of 7.66 and 8.99, 6.26 and 8.81, and 7.94 and 8.78 g dl-1, respectively.2+ that the indigenous T. vivax strains are more

Animals↗
PubMed1990

Electrophoresis of bovine erythrocyte sialic acids: existence of additional band in trypanotolerant Ndama cattle.

Mild acid-hydrolysis of erythrocyte surface sialic acids of the trypanotolerant Ndama and the trypanosusceptible White/Fulani Zebu breeds of cattle was performed. The cleaved sialic acids from the two breeds of cattle were simultaneously subjected to polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate (SDS-PAGE), along with commercial standard N-acetylneuraminic acid (MW 309.28), blank gel and plasma proteins. The cleaved sialic acids migrated in the globulin fractions, as shown by the plasma protein electrophoresis. While the Ndama and the Zebu erythrocytes had one migrating band each of which coincided with the standard N-acetylneuraminic acid, the Ndama had another trailing band of sialic acid, of an estimated molecular weight of 30 kDa, which may account for the higher erythrocyte sialic acid concentrations of the Ndama. This additional band was absent in the Zebu. All these bands were readily reproducible.

Animals↗
PubMed1989

Neutrophil myeloperoxidase deficiency associated with canine hepatozoonosis.

Hepatozoonosis is a very important disease in dogs in Nigeria. Hepatozoonosis was reported in Nigeria in 18 dogs. The clinical signs included fever, anorexia, loss of weight, lameness, oculonasal discharge and conjunctivitis. Hematologic findings included leukocytosis due to neutrophilia and eosinophilia. Parasitemia varied from 1 to 9% of the circulating neutrophils in the peripheral blood smears of the dogs examined. Hepatozoon canis gametocytes were identified in circulating neutrophils of dogs. Peripheral blood smears from dogs confirmed to have natural H. canis infection were cytochemically stained for myeloperoxidase. Parasitized neutrophils were myeloperoxidase deficient while non-parasitized neutrophils were myeloperoxidase positive. This is considered important, because deficiency of the enzyme may be responsible for poor response of H. canis to chemotherapeutic agents.

Animals↗
PubMed1988

Frequency of involvement of pox virions in lesions of bovine dermatophilosis.

By combined electron microscopical and serological methods the rate of involvement of pox virions within lesions of bovine natural dermatophilosis was determined. Scabby lesions of 40 (77%) out of a total of 52 cases were positive for the virions, while sera of all infected animals which reacted positively for pox viral antibodies (LSD) was significantly higher (P less than 0.001) in comparison to those of healthy-appearing animals. The virions in all cases had a uniform oval to cylindrical morphology with a mean measurement of 110 X 280 nm. A synergistic interplay involving the initiation of the scabby lesions by the virions and their subsequent trapping within keratin deposits, followed by their release through the keratolytic activity of Dermatophilus congolensis appear to have obtained in cases.

Actinomycetales Infections↗
PubMed1987

Effect of pregnancy on clinical manifestation of bovine trypanosomiasis.

Four groups of non-pregnant, first second and third trimester pregnant Zebu heifers were used to study and compare the clinical manifestations of Trypanosoma vivax infection. All the infected heifers developed clinical trypanosomiasis manifested by massive parasitaemia, fluctuating pyrexia, anaemia, dull hair coat, emaciation, jugular pulse and enlarged superficial lymph nodes. There were group variations in the severity of signs shown. Infected non-pregnant heifers and heifers in the third trimester of pregnancy developed a more severe form of the disease than pregnant heifers in the first and second trimesters of pregnancy.

Animals↗
PubMed1986

Effects of experimental Trypanosoma vivax infection on first-, second-, and third-trimester pregnancy in heifers.

The effects of Trypanosoma vivax on pregnancy were studied in 18 heifers. The heifers were bred by a proven bull and divided into three groups of six heifers each. In the first group, four heifers were infected with T . vivax on Day 60 (first trimester) of pregnancy; two other pregnant heifers were uninfected controls. The second and third groups were similarly infected in the fourth (second trimester) and seventh (third trimester) month of pregnancy. One infected heifer in the first-trimester group aborted 39 days postinfection (p.i.); the remaining three had relatively normal gestation and parturition. In the second-trimester group, the pregnancies were carried to term with normal deliveries. In the third-trimester group, three infected heifers (75%) had premature deliveries while the fourth died about three hours after the full-term calf was pulled out. All of the control heifers had normal gestation and parturition. No gross abnormalities were seen in the placentae of the infected heifers, but histological sections of the heifers infected in the third trimester of pregnancy revealed more mononuclear cells than in those of the uninfected controls. Postmortem examination of the dead premature calves showed lymphadenopathy, splenomegaly, serous atrophy of perirenal and pelvic fat, epicardial petechiae, and blood-tinged peritoneal and pericardial fluids. Histologically, there were slight myocardial haemorrhages and edema. T. vivax was recovered from the blood of one of the premature calves. Both birth weights and PCV were affected by the experimental maternal infection in the first- and third-trimester calves. The birth weights and PCV of calves of infected dams were lower than those for the calves of the control heifers. This work therefore demonstrates transplacental transmission of T. vivax in heifers.

Journal Article↗
PubMed1984

Bacteriological investigation of the postpartum uterus: Relationship to involution and histopathological findings.

A bacteriological investigation of the postpartum uteri of suckled and nonsuckled Bunaji (White Fulani) cows was undertaken to determine the microflora, the effect of suckling on the flora and the influence of the flora on uterine involution and histopathology. Uterine contamination by bacteria was highest between days 10 and 21 postpartum with Staphylococcus aureus being the commonest organism isolated. There was no consistent isolation of one type of bacterial organism from a cow throughout the sampling period. Suckling did not affect the incidence of uterine contamination by bacteria. Foci of leucocytes (mainly lymphocytes) were found in uterine sections in an increasing frequency with days postpartum. Bacteria were isolated from only 3 of the 12 uteri that had the leucocytic foci. Uterine involution was normal and complete by 25 days after calving irrespective of the presence or absence of bacteria or leucocytic foci. We concluded that postpartum uterine contamination by bacteria was not influenced by suckling and that puerperal uterine contamination by bacteria did not interfere with the normal process and duration of uterine involution.

Journal Article↗
PubMed1983

Quantitative estimation of spermatogenesis in bulls (Bos indicus) in a tropical environment of Nigeria.

Spermatogenesis in bulls (Bos indicus) indigenous to Nigeria, and the significance of Sertoli cell index (SCI) as a measure of testicular degeneration were studied. The mean testicular weights and dimensions were lower than reported for Bos taurus breeds. The diameters of the seminiferous tubules were lower than reported for Bos taurus, although within the same range. Inter-month and intra-month variations were highly significant (P less than 0.01). A mean annual spermatogenesis of 77.60% was reported. Active spermatogenesis was observed throughout the year, with a peak during the rainy season and extending toward the pre-dry season. This was consistent with previous reports. Severe testicular degeneration was found to influence spermatogenesis. This was reflected in the decrease in SCI. Mild degeneration had no significant effect on spermatogenesis, and did not significantly change the SCI. The SCI was defined as the ratio of the number of germinal cells to the number of Sertoli cells in the same cross sections of tubules.

Animals↗
PubMed1980

Effect of scrotal streptothricosis on spermatogenesis in the bull.

Cutaneous streptothricosis was observed in 171 (13.42 per cent) out of 1274 animals examined over a period of 12 months. Eighty-six (8.30 per cent) of the 1036 bulls examined had cutaneous and scrotal streptothricosis and 85 (35.71 per cent) of the 238 cows had cutaneous streptothricosis of varying degrees. More cattle were affected during the rainy and pre-dry seasons when the condition was more extensive and severe. Histologically, moderate testicular degeneration was observed in 15 (13.6 per cent) of 110 streptothricosis-free bulls and 14 (16.3 per cent) of the 86 bulls with scrotal streptothricosis. No correlation was found between scrotal streptothricosis and testicular degeneration and, or inflammation. Average percentage spermatogenesis was 89.7 per cent for normal bulls, 91.2 per cent and 89.5 per cent for bulls with mild and moderate scrotal streptothricosis respectively and 88.0 per cent for bulls with severe scrotal streptothricosis. Two chronic cases had an average percentage spermatogenesis of 89.0 per cent. There was no correlation between the degree and extent of scrotal streptothricosis and spermatogenesis. The slight increase in the thickness of the scrotum was not observed to affect the normal course of spermatogenesis.

Actinomycetales Infections↗