Seroprevalences of vector-transmitted infections of small-holder dairy cattle in coastal Kenya.

A cross-sectional study was carried out from July to September 1989 in Kaloleni Division, Coast Province, Kenya to estimate the prevalence of vector-transmitted diseases in small-holder dairy cattle and to identify the risk factors associated with different management systems. One hundred and thirty of the 157 herds with dairy cattle in Kaloleni Division were surveyed. These were from three agro-ecological zones (coconut-cassava, cashew nut-cassava and livestock-millet), comprised two management systems (stall-feeding and herded grazing) and were herds with either dairy cattle only or with Zebu and dairy cattle. A formal questionnaire sought answers to questions on cattle health and management practices. A total of 734 dairy and 205 Zebu cattle in 78 dairy and 52 mixed (dairy and Zebu) herds were sampled and screened for haemoparasites (Trypanosoma, Anaplasma, Babesia, and Theileria infections). Sera were tested for antibodies to Theileria parva, using the schizonts-antigen indirect fluorescent-antibody (IFA) test and to antibodies for Babesia bigemina and antigens to Anaplasma marginale by enzyme-linked immunosorbent assay (ELISA). Packed-cell volume (PCV) also was measured. Tick-control measures were practised by all except three of the farmers. Despite this, overall seroprevalence to T. parva was >70%--suggesting either that control practices were not strictly implemented or they were ineffective. The seroprevalence of T. parva in adult cattle kept in stall-feeding systems in the coconut-cassava zone was significantly lower (57+/-8% (S.E.)) than in herded-grazing systems (79+/-3%) and there was no association between antibody prevalence and age of cattle in this zone. Antibody prevalences in cattle in the cashew nut-cassava and the drier livestock-millet zone increased with age. Cattle in herded-grazing systems had an overall lower seroprevalence of T. parva infection in the livestock-millet zone (45+/-6%) than in the other two zones. Analysis was confined to the coconut-cassava zone for B. bigemina and to the coconut-cassava and cashew nut-cassava zones for A. marginale. Mean prevalences of B. bigemina were 40.9+/-9 and 73+/-6% for dairy cattle under stall-feeding and herded-grazing systems, respectively, and increased with age. Antigen prevalences of A. marginale were over 80% in all age groups of cattle in the coconut-cassava and cashew nut-cassava zones. Overall trypanosome prevalence in cattle was <1%. Trypanocidal treatment was uncommon. The variations in antibody prevalence associated with risk factors such as feeding system, agro-ecological zone and age of animal suggest that management system influenced exposure to tick-borne infection (particularly, T. parva infections) in small-holder dairy cattle in coastal Kenya.

A longitudinal study of disease incidence and case-fatality risks on small-holder dairy farms in coastal Kenya.

A longitudinal study was carried out in the coastal lowlands coconut-cassava agro-ecological zone of Kaloleni Division, Coast Province, Kenya between June 1990 and December 1991 to estimate disease incidence and cause-specific case-fatality risk in an average of 120 cattle in 26 small-holder dairy herds kept in two grazing-management systems. East Coast fever (ECF) was the predominant disease diagnosed; the mean monthly incidence rate was 2.5 and 6.9% in animals < or = 18 months of age under stall-fed and herded-grazing systems, respectively. In cattle > 18 months of age, the monthly incidence rate was < 1%. The 6-month ECF incidence rate was 20+/-8% (S.E.) in the stall-feeding system compared with 39+/-7% in the herded-grazing systems. There was a gradual increase in antibody prevalence with age to over 90% in cattle over 18 months of age in herded-grazing systems, whilst less than a third of cattle in the stall-feeding systems were sero-positive at any age. Overall accumulated mortality to 18 months of age was estimated to be 56%. Annual mortality in cattle > 18 months averaged 9%. Cattle managed in the herded-grazing system had a 60% higher mortality, although not significantly so, than those fed in stalls. Deaths due to ECF accounted for over two-thirds of the deaths. ECF was then the major disease constraint to small-holder dairy production in the coconut zone of coastal Kenya. Clinical cases occur the whole year round (especially in young stock)--despite apparent tick control, and in both herded-grazing and stall-feeding system.

Identification of a target population for immunisation against East Coast fever in coastal Kenya.

Two experiments were carried out to identify the target population of cattle for immunisation against East Coast fever (ECF) using the infection-and-treatment method. Firstly, a sentinel-calf study was used to determine the age window for ECF immunisation by determining ages at clinical detection of infection with Theileria parva. Six groups of five naive cross-bred (Bos taurus/Bos indicus) male calves, introduced at intervals of 2 months at a mean age of 26 days, were exposed to natural tick challenge on a high ECF-risk, small-holder farm in the coastal lowland, coconut-cassava agro-ecological zone of coastal Kenya. Secondly, a challenge study evaluated the relationship between the presence of T. parva antibodies and immunity. Ten indigenous adult Zebu cattle and nine Zebu young stock purchased from farmers in the same zone, and eight cross-bred calves (survivors of the sentinel-calf study) were challenged with 10 times the immunising dose of T. parva Marikebuni stock. Twenty-four of these 27 cattle had high antibody titres before challenge. Two cross-bred calves, obtained from an ECF-free area and seronegative to T. parva schizont antigen, also were challenged and used as susceptible controls. Twenty-five (83%) of the 30 sentinel calves contracted ECF over an age range of 36-116 days (mean 72 days). The remaining five calves died of other causes within 2 months of arrival on the farm. Fourteen of the 25 calves survived the infection and developed antibodies to T. parva. Despite tick control, seven of these 14 calves had a second episode of ECF and two died. In total, 13 of the 25 calves that contracted ECF died. Only one of 19 indigenous Zebu animals developed clinical ECF when challenged with T. parva Marikebuni (mild clinical signs with spontaneous recovery). Of the eight cross-bred survivors from the first experiment, only one succumbed to ECF when challenged and it died. Both susceptible cross-bred calves developed severe clinical signs of ECF and one died. The experimental studies show that in the high ECF-risk areas of the coconut-cassava zone of coastal Kenya, immunisation against ECF in cross-bred (B. taurus/B. indicus) cattle should be targeted at an early age (preferably within 1-2 months of birth).

Resistance of Galla and Small East African goats in the sub-humid tropics to gastrointestinal nematode infections and the peri-parturient rise in faecal egg counts.

A study was carried out from 1994 to 1996 to compare the resistance to naturally acquired gastrointestinal (GI) nematode infections (predominantly Haemonchus contortus) of 88 Galla and 114 Small East African (SEA) goats (does) in the sub-humid coastal region of Kenya. Live weights (LWT), blood packed cell volume (PCV) and faecal egg counts (FEC) were recorded each year at mating, 3-4 months after mating, 1-2 weeks before kidding and 1-4 months after kidding. There was a significant increase in FEC and a decline in PCV in lactating does compared to non-lactating does over the peri-parturient period. This peri-parturient rise in FEC occurred in both breeds but was more marked and persistent in the Galla than in the SEA. The SEA does were more resistant to GI nematode infections than Galla does as shown by their significantly lower FEC and higher PCV at all sampling times over the reproductive cycle, but this breed difference was particularly marked over the lactation period.

Objective estimates of the probability of death from burn injuries.

BACKGROUND: Over the past 20 years, there has been remarkable improvement in the chances of survival of patients treated in burn centers. A simple, accurate system for objectively estimating the probability of death would be useful in counseling patients and making medical decisions. METHODS: We conducted a retrospective review of all 1665 patients with acute burn injuries admitted from 1990 to 1994 to Massachusetts General Hospital and the Shriners Burns Institute in Boston. Using logistic-regression analysis, we developed probability estimates for the prediction of mortality based on a minimal set of well-defined variables. The resulting mortality formula was used to determine whether changes in mortality have occurred since 1984, and it was tested prospectively on all 530 patients with acute burn injuries admitted in 1995 or 1996. RESULTS: Of the 1665 patients (mean [+/-SD] age, 21+/-20 years; mean burn size, 14+/-20 percent of body-surface area), 1598 (96 percent) lived to discharge. The mean length of stay was 21+/-29 days. Three risk factors for death were identified: age greater than 60 years, more than 40 percent of body-surface area burned, and inhalation injury. The mortality formula we developed predicts 0.3 percent, 3 percent, 33 percent, or approximately 90 percent mortality, depending on whether zero, one, two, or three risk factors are present. The results of the prospective test of the formula were similar. A large increase in the proportion of patients who chose not to be resuscitated complicated comparisons of mortality over time. CONCLUSIONS: The probability of mortality after burns is low and can be predicted soon after injury on the basis of simple, objective clinical criteria.

Evidence for multiple anthelmintic resistance in sheep and goats reared under the same management in coastal Kenya.

Four experiments, two with sheep and two with goats, were carried out to determine the efficacy of ivermectin, fenbendazole, levamisole, closantel and some of their combinations by faecal egg count reduction tests. In the first experiment, injectable ivermectin, oral ivermectin, fenbendazole and levamisole were tested in 6-month-old lambs, and their reduction percentages were 77%, 13%, 42% and 92%, respectively. In the second experiment, with yearling sheep, the reduction percentages were 35% for injectable ivermectin, 32% for fenbendazole, 99% for levamisole, 48% for closantel, 92% for injectable ivermectin combined with fenbendazole, 99% for injectable ivermectin combined with levamisole, and 100% for fenbendazole combined with levamisole. In the study with 18-month-old goats given the same dose rates as those recommended for sheep, the reduction percentages were 73% for injectable ivermectin, 25% for fenbendazole, and 78% for levamisole. Another group of 14-month-old goats was treated with dose rates 1.5 times those recommended for sheep and the reduction percentages were 93% for levamisole, 92% for injectable ivermectin, and 97% for a combination of levamisole and ivermectin. In all experiments with sheep and goats the gastrointestinal nematode parasites identified by larval cultures were Haemonchus contortus, Trichostrongylus spp. and Oesophagostomum spp. The gastrointestinal nematodes of both sheep and goats on this farm are resistant to ivermectin and fenbendazole, whereas levamisole is still effective in sheep, but not in goats. The results are discussed in relation to the farm as a source of breeding stock to smallholder farmers and its potential to spread anthelmintic resistance.

Assessing the economic impact of immunisation against East Coast fever: a case study in coast province, Kenya.

The cost of immunising cattle against East Coast fever by the infection and treatment method has been calculated for a pilot scheme in Kaloleni Division of the Coast Province of Kenya by using a spreadsheet model. The cost was calculated to be KSh 544 (US$25) per animal (in 1990 values). If a farmer were to bear all this cost, immunisation would be financially profitable in grade cattle, but the benefits of immunisation would not be sufficient to justify the immunisation of zebu cattle. For these animals, the cost of immunisation would have to be in the range of KSh 230 to KSh 415 per animal, or the farm-gate price of milk would have to increase by at least 80 per cent from KSh 7.50 to 13.50/litre, or the government would have to subsidise the cost either partially or fully. The first two possibilities are realistic, because the costs of routine immunisation are likely to be lower than for the pilot scheme, and because the increasing demand for milk is likely to push up prices in the liberalised markets. If both the grade and zebu cattle in Kaloleni Division were targets for immunisation, it is estimated that there would be 14,500 head for immunisation annually, costing an estimated KSh 8 million. The spreadsheet model used to assess the economics of immunisation in the Kaloleni Division could be applied to determine the government or private veterinary service charges for immunisation that would be financially profitable to farmers in a defined cattle production system in any division, district or country. The model could also be used to estimate the annual total number of cattle for immunisation in a target cattle production system and thus help with the financial planning for the exercise.

Dynamics of photoinduced cell plasma membrane injury.

We have developed a video microscopy system designed for real-time measurement of single cell damage during photolysis under well defined physicochemical and photophysical conditions. Melanoma cells cultured in vitro were treated with the photosensitizer (PS), tin chlorin e6 (SnCe6) or immunoconjugate (SnCe6 conjugated to a anti-ICAM monoclonal antibody), and illuminated with a 10 mW He/Ne laser at a 630 nm wavelength. Cell membrane integrity was assessed using the vital dye calcein-AM. In experiments in which the laser power density and PS concentration were varied, it was determined that the time lag before cell rupture was inversely proportional to the estimated singlet oxygen flux to the cell surface. Microscopic examination of the lytic event indicated that photo-induced lysis was caused by a point rupture of the plasma membrane. The on-line nature of this microscopy system offers an opportunity to monitor the dynamics of the cell damage process and to gain insights into the mechanism governing photolytic cell injury processes.

The dose-response relationship of controlled-release codeine (Codeine Contin) in chronic cancer pain.

The improved pain control provided by regular dosing of opioid analgesics in patients with severe cancer pain has been well established. However, the treatment of mild-to-moderate cancer pain is often limited to "as needed" dosing with fixed combinations of codeine or oxycodone plus a nonopioid analgesic, which do not allow optimal titration of the individual components. This randomized double-blind study was designed to evaluate the efficacy of controlled-release codeine (Codeine Contin) in patients with cancer pain, and to estimate its dose equivalence to a standard combination of acetaminophen plus codeine. Twenty-four patients with at least moderate cancer pain were randomized to Codeine Contin 100, 200, or 300 mg every 12 hr or acetaminophen plus codeine (600 mg/60 mg) every 6 hr. On days 1 and 4 of dosing, pain intensity and pain relief were assessed hourly for 12 hr. The sum of pain intensity differences (SPID) from baseline and the total pain relief (TOTPAR) scores demonstrated a dose-response relationship for Codeine Contin on days 1 and 4 that was statistically significant on day 1 and suggested greater analgesic efficacy on day 4, compared with day 1. Codeine Contin 150 mg every 12 hr was estimated to be equianalgesic to acetaminophen plus codeine (600 mg/60 mg) given every 6 hr. Because a similar equivalence was also demonstrated from analysis of adverse event data, it is concluded that Codeine Contin 150 mg produces analgesia and a side-effect profile similar to a 40% lower dose of codeine provided by the combination.(ABSTRACT TRUNCATED AT 250 WORDS)

Crossbreeding of Ayrshire, brown Swiss, and Sahiwal cattle for annual and lifetime milk yield in the lowland tropics of Kenya.

Records from 1577 cows born from 1973 to 1983 on a ranch in lowland Kenya were analyzed for age at first calving, lactation length, lactational milk yield, calving interval, annual milk yield, and, for cows born from 1973 to 1979, number of calvings, productive lifetime in the herd, and lifetime milk yield. Partial lifetime yield (< or = 4 lactations) was studied for all cows. Rotational crosses of Ayrshire and Sahiwal, the crosses between them (interbreds), and the crosses sired by Brown Swiss from the rotational crosses were compared. The Ayrshire-sired rotational crosses yielded 4.8% more milk during a 19-d longer lactation and with a calving interval that was 14 d longer than those sired by Sahiwal. Milk yield for completed lactations of interbred cows was 4.5% less, and milk yield of Brown Swiss crosses was 9.5% more, than the average of the rotational crosses. Lifetime milk yields were 48% greater for the rotational crosses sired by Ayrshire than for those sired by Sahiwal. Interbreds yielded 34% less than the average of the rotational crosses. Over partial lifetimes, the rotational crosses sired by Ayrshire yielded 45% more milk than those sired by Sahiwal; the interbreds and the crosses sired by Brown Swiss yielded 34% less and 62% more milk, respectively, than the mean of the rotational crosses.

Lactational performance of Jersey cows given Napier fodder (Pennisetum purpureum) with and without protein concentrates in the semi-humid tropics.

Two experiments with 12 and 18 lactating Jersey cows respectively were carried out in the coastal semi-humid zone of Kenya to assess the performance arising from the feeding of chopped Napier fodder (Pennisetum purpureum) given ad libitum with and without one of three sources of protein; fishmeal, copra cake and freshly cut Leucaena (Leucaena leucocephala). Each source supplied approximately 300 g crude protein daily. Dry matter intakes of Napier fodder fed alone averaged 7.1 and 5.5 kg in Experiments 1 and 2 respectively. Additional protein did not affect Napier fodder intake, but total intakes of dry matter were higher for the cows receiving the protein supplements, differences which were significant (P < 0.05) in Experiment 2. Average daily milk production from cows fed Napier fodder alone was 6.4 and 4.2 kg in Experiments 1 and 2 respectively. The additional 300 g crude protein increased milk production by 1.0 to 1.6 kg/day, increases which, except that for fishmeal, were significant (P < 0.05). Weight losses of the cows were either reduced or changed to weight gains by the provision of protein. The results are assessed in relation to the energy and protein requirements for milk production.

Antibody Targeted Photolysis.

The technique of Antibody Targeted Photolysis (ATPL) is reviewed from an historical perspective with a summary of the literature since the first experiments were performed in 1983. Attention is given to both the biological and photophysical properties of the various immunoconjugates that have been developed. References to critical discoveries and competing technologies in the photodynamic literature are given. Topics include: synthesis of immunoconjugates, in vitro vs. in vivo toxicity, in vivo biodistribution, immunoconjugate delivery, photosensitizer selection based on photophysical properties, light delivery for specific applications, oxygen requirements, and other physicochemical phenomena. A mathematical model of the dynamics for cell killing based upon the transport of phototoxins to the cell surface is developed. A generalized set of coupled differential equations is given, which conveniently summarizes the manifold requirements stressed earlier for successful cell killing. Solutions are then presented for an idealized set of conditions appropriate for an isolated tumor cell. Suggestions for further improvements and follow-up experiments are made that could help in the evolution of ATPL into a useful clinical therapy and/or probe for cell biological studies.

Genetic and environmental variation in reproductive and lactational performance of Jersey cattle in the coastal lowland semi-humid tropics.

Reproductive and lactational performances, including length of productive life, were evaluated from records for 1960 to 1988 for a Jersey herd in coastal lowland semi-humid Kenya. The herd grazed natural pastures and until the mid 1970s received supplementary feeding. Mean performance included 31 months age at first calving, lactation milk yield (MY) of 1,788 kg in 3.3 lactations and a calving interval (CI) of 408 days. Mean milk yields declined from over 2,200 kg in the 1960s to about 1,500 kg in the 1980s with concomitant changes in calving interval, length of productive life and infertility. While annual genetic components of change in MY and CI were not significantly different from zero, the environmental components were large and significant (P < 0.01) showing that the declines in performance probably resulted from decreased feed availability and less efficient disease control. Estimates of genetic parameters were consistent with those in the literature. With good management purebred Jersey cows in coastal lowland semi-humid Kenya were productive, but animal and herd productivity were highly dependent on management level which had a major effect on both milk yield and reproductive wastage.

Antibody-targeted photolysis: in vitro immunological, photophysical, and cytotoxic properties of monoclonal antibody-dextran-Sn(IV) chlorin e6 immunoconjugates.

A set of anti-melanoma immunoconjugates were prepared which contained chlorin e6: antibody molar ratios of 18.9:1, 11.2:1, 6.8:1, and 1.7:1. All immunoconjugates retained antigen binding activity regardless of the chromophore:antibody substitution ratio that was attained. In contrast, the ground-state absorption spectra of the immunoconjugates showed features which appeared to be dependent on the chromophore:antibody molar ratio. In addition, the quantum yield of singlet oxygen generated by the conjugated chromophores was observed to be significantly less than that observed with the unbound dye. Time-resolved absorbance spectroscopy of the chromophore excited triplet state indicated that the loss of singlet oxygen quantum yield resulted from diminished chromophore triplet yield. Analysis of data obtained from in vitro photolysis of target melanoma cells, in combination with that obtained from the immunochemical and photochemical studies, indicates that the observed immunoconjugate phototoxicity can be reasonably quantitatively represented by (1) the ability of the immunoconjugate to bind SK-MEL-2 cell surface antigen, (2) the amount of chromophore localized at the target cells by immunoconjugate binding, (3) the delivered dose of light at 634 nm, and (4) the singlet oxygen quantum yield of the antibody-bound photosensitizer. Though these data argue strongly for photolysis by the cumulative dosage of singlet oxygen at the cell membrane, nonetheless, the concurrent photoinduced release of other cytotoxic agents should not be ruled out.

The physician's appearance and professionalism.

The attire of 101 physicians in 24 Minnesota clinics was observed, and the relationships between appearance and 1) gender, 2) role, and 3) location were analyzed. Comparisons between resident and staff physicians revealed several significant differences. The results suggest that the physician's appearance affects how others view the physician as a professional.

Odorous urine following asparagus ingestion in man.

The production of odorous urine after the ingestion of asparagus has been shown to occur in 43% of 800 volunteers investigated. This characteristic is reproducible over a 12-month-period and has been shown to remain with individuals for virtually a lifetime. Family studies suggest that the ability to produce the odorous urine is inherited as an autosomal dominant trait.

Osteonecrosis in sickle cell trait.

Osteonecrosis is common in sickle cell anemia but has been rarely reported with sickle cell trait. Two cases of osteonecrosis of the femoral head caused by sickle cell trait are presented. One patient's diagnosis was delayed because the association of osteonecrosis and sickle cell trait was not recognized. The previous reported cases of this association are discussed, emphasizing diagnostic implications for 12 black patients presenting with hip pain.

N-Terminal sequence of human big gastrin: sequence, synthetic and immunochemical studies.

The previously assigned structure of human big gastrin is revised as a result of sequencing and immunological studies on synthetic peptides. A nonadecapeptide has been synthesized and found to have full immunochemical potency compared with natural human G34 in a radioimmunoassay which is specific for the N-terminal sequence. Syntheses of the peptides were achieved using the stepwise procedure with benzyloxycarbonyl-amino acids and fragment couplings mediated mainly by the dicyclohexylcarbodiimide procedure in the presence of either N-hydroxysuccinimide or 1-hydroxybenzotriazole. Purification of the peptide fragments was by Sephadex LH-20 chromatography and removal of protecting groups was effected using 90% trifluoroacetic acid in the presence of scavengers. Purification of the nonadecapeptide was achieved by high performance liquid chromatography.

Procollagens as markers for the cell of origin of human bone tumors.

Cells derived from osteogenic sarcomas and from Ewing's sarcomas, two malignant bone tumors, were examined for the types of collagens they elaborated into the tissue culture media. Type I procollagen was the predominant species from all osteogenic sarcoma cell lines, a finding consistent with bone cell origin. The Ewing's sarcoma cells contained a prominent peak of type III procollagen and resembled the profile of vascular smooth muscle cells. Fibroblasts derived from skin biopsies taken from amputation specimens synthesized both type I and type III procollagens at the expected ratio of approximately 3:1. The examination of matrix proteins may provide a general classification scheme for human sarcomas and permit distinction of one tumor from another, as well as from normal fibroblasts.