Financial analysis of dipping strategies for indigenous cattle under ranch conditions in Uganda

A financial analysis was performed to assess the performance of three acaricide-treatment groups of indigenous breeds (Zebu and Nganda) of cattle on a ranch in Luwero District, Uganda. The treatments were based on different frequencies: twice-a-week dipping, once-a-month dipping and no tick control. The objective was to evaluate the economic justification for intensive acaricide application for tick and tick-borne disease control in Uganda. Data were collected by monitoring cattle performance over a period of 34 months. Biological data collected included the number of cows at the beginning and end of the study, net starting liveweight, number of calves born, number of animals dying due to tick-borne diseases and other causes, number of animals sold or slaughtered and milk yield. Records of variable costs (acaricides, drugs, labour, etc.) and output prices were assembled and calculated by treatment group. Gross margin and marginal analysis were used in the financial analysis. The exchange rate in 1990-1993 was one US$ to 1200 Uganda shillings. The gross benefits obtained from animal sales, herd value and milk yield were Uganda shillings 1175, 1389 and 1311 per kg of net starting liveweight for animals dipped twice-a-week, once-a-month and not dipped, respectively. The variable costs were Ug. shs. 424, 390 and 360 per kg of net starting liveweight, respectively. Consequently, the gross margins were Ug. shs. 751, 999 and 951 per kg of net starting liveweight. Furthermore, the marginal rate of return (MRR) in changing from no tick control to once-a-month dipping was 160%, while changing from no tick control to twice-a-week dipping was negative (-313%). The above results showed that the value of increased gains in production obtained from twice-a-week dipping strategy does not offset the costs of inputs for intensive dipping. Once-a-month dipping (strategic) therefore appears to be the most-profitable tick-control strategy for the farmer. The need to conduct further studies in different livestock- production systems and to rationalise future tick control policies is discussed.     

(-) mating type-specific mutants of Phycomyces defective in sex pheromone biosynthesis

We have isolated the first mating type-specific mutants in mucoraceous fungi. Both mutants in Phycomyces blakesleeanus appear to be defective in the same gene. The gene, present in both mating types, is necessary only in cultures of the (-) mating type. The gene codes for an enzyme in sex pheromone biosynthesis. The pheromone precursor made by the mutants is detectable only in cross-feeding experiments. The biological and solubility properties of the precursor suggest the precursor is 4-dihydrotrisporin, a metabolite of beta-carotene. Separate studies with beta-carotene-deficient mutants and Compound-P, a new chemically synthesized precursor of the pheromones, imply the constitutive level of enzymes for pheromone biosynthesis in Phycomyces is extremely low. In comparison, the level of enzymes for pheromone conversion to trisporic acid is higher. The mating type-specific mutants also catalyze the conversion of (+) pheromone to trisporic acid. This finding was unexpected because literature models predicted this reaction was catalyzed by the same enzyme which catalyzed the conversion of 4-dihydrotrisporin to (-) pheromone-a reaction missing in the (-) mating type-specific mutants. Thus, we propose a revised model for trisporic acid biosynthesis.     

An Escherichia coli hemolysin transport system-based vector for the export of polypeptides: export of Shiga-like toxin IIeB subunit by Salmonella typhimurium aroA

1. We describe the first application of microdialysis to monitor the pharmacokinetics of a drug in the blood of man. 2. The aims of the study were to ascertain patient acceptability and tolerability of a new microdialysis probe and to assess its accuracy in determining the pharmacokinetics of levodopa and its principal plasma metabolite 3-O-methyldopa (3-OMD). 3. Eight patients with parkinsonism on chronic levodopa therapy were investigated. 4. After an overnight fast, a flexible microdialysis probe, perfused with isotonic saline, was inserted into a forearm vein and a blood sampling cannula was inserted in a forearm vein of the other arm. After ingestion of a levodopa preparation (Madopar Dispersible), dialysate was collected over 5 or 10 min periods and blood samples were taken every 15 or 30 min for 2-6 h. 5. Dialysate drug profiles were similar to those of plasma, and levodopa and 3-OMD concentrations exhibited significant (P < 0.001) correlation with those observed in the corresponding plasma samples. 6. The mean (+/- s.d.) blood dialysate concentrations for levodopa and 3-OMD were 36.1 +/- 9.2% and 43.4 +/- 8.4% respectively of the plasma content. 7. The tolerability of the probe was excellent, and all eight patients found it preferable to conventional blood sampling. 8. Microdialysis of blood is less invasive than frequent intermittent direct blood sampling, and can readily be used to continuously monitor levodopa pharmacokinetics. In a clinical setting, a combination of drug monitoring by this technique together with clinical evaluation of motor function can be used to optimize levodopa treatment in patients with Parkinson's disease.     

Catastrophic failure of a conforming type of total knee replacement: a case report

A case study is presented to illustrate the concept of femoral component failure secondary to polyethylene wear in a 67 year old man, 13 years after he had conforming type total knee replacements. This case illustrates the theory that this observed problem may be a leading cause of failure in conforming and nonconforming total knee replacements in the future.     

Multiple prosthetic infections after total joint arthroplasty. Risk factor analysis

The relative risk of age, sex, underlying diagnosis, corticosteroid usage, diabetes mellitus, and major nonprosthetic infection for the development of multiple prosthetic infections was assessed retrospectively. Deep infection occurred in 174 replacement arthroplasties in 145 patients between 1981 and 1993. Patients with rheumatoid arthritis had a significantly larger number of implants per patient (P < .001). Twenty-seven of 145 patients developed a second prosthetic infection, for an overall incidence of 19%. Of these 27, the underlying diagnoses were rheumatoid arthritis in 19, osteoarthritis in 6, neuropathic arthritis in 1, and systemic lupus erythematosus in 1. Rheumatoid arthritis and the occurrence of a major nonprosthetic infection (sepsis) were found to be highly associated with the development of a second prosthetic infection (P < .001 and P = .0001, respectively). In those rheumatoid patients with multiple infections, there was a significantly larger proportion with American Rheumatism Association class III and IV function than those with a single prosthetic infection (P = .0002). In 14 of the 27 cases of more than one prosthetic infection, the infected implants presented clinically within the same month. Ten of these 14 had an associated nonprosthetic infection. It is therefore not possible to accurately calculate the risk that one infected arthroplasty poses to other implants.     

Treatment of depression by obstetrician-gynecologists: a survey study

OBJECTIVE: We performed an exploratory survey of depression diagnosis, treatment, and patient referral patterns by Fellows of ACOG. We also examined obstetrician-gynecologists' professional training in the management of clinical depression. METHODS: We sent a questionnaire to a total of 1370 ACOG Fellows. Sixty percent of the surveys were returned. RESULTS: As a group, obstetrician-gynecologists reported diagnosing an average of four new cases of depression per month. Within the overall sample, the number of new diagnoses of depression made each month was significantly greater for those defining themselves as primary care physicians than for those defining themselves as specialists. When treating depression pharmacologically, obstetrician-gynecologists reported that they overwhelmingly (74% of the time) chose selective serotonin reuptake inhibitor antidepressants. Ninety-five percent of obstetrician-gynecologists reported that they referred severely depressed patients to a mental health professional. A majority of respondents neither received residency training (80%) nor completed a continuing medical education course (60%) on the treatment of clinical depression in women. CONCLUSION: Obstetrician-gynecologists who describe themselves as primary care physicians make significantly more diagnoses of depression than those considering themselves specialists. Studies further to assess obstetrician-gynecologists' management of depression and better to define needs for professional education are warranted.     

Randomization test for coupled data

Coupled data arise in perceptual research when subjects are contributing two scores to the data pool. These two scores, it can be reasonably argued, cannot be assumed to be independent of one another; therefore, special treatment is needed when performing statistical inference. This paper shows how the Type I error rate of randomization-based inference is affected by coupled data. It is demonstrated through Monte Carlo simulation that a randomization test behaves much like its parametric counterpart except that, for the randomization test, a negative correlation results in an inflation in the Type I error rate. A new randomization test, the couplet-referenced randomization test, is developed and shown to work for sample sizes of 8 or more observations. An example is presented to demonstrate the computation and interpretation of the new randomization test.