Risk of HIV infection from transfusion with blood negative for HIV antibody in a west African city.

OBJECTIVE--To estimate the risk of infection with HIV (HIV 1 or HIV 2, or both) from transfusion of a screened unit of blood in a high prevalence area in west Africa. DESIGN--Retrospective cohort study for January-July 1991. SETTING--National Blood Transfusion Centre, Abidjan, Côte d''Ivoire. SUBJECTS--Repeat donors (5831 units of blood) and first time donors (5076 units) in the first five months of 1991. MAIN OUTCOME MEASURES--Prevalence and estimated incidence of HIV infection in repeat and first time donors; estimated rate of potentially infected, HIV antibody negative units; and rate of (false negative) potentially infected units assuming a laboratory test sensitivity of 99%. RESULTS--Overall HIV prevalence was 11.0% in first time donors and 2.1% in repeat donors. In the first seven months of 1991, 29 HIV antibody positive (27 HIV 1, 1 HIV 2, 1 dually reactive) donors with a seronegative unit of blood earlier in the year were identified; 26 had donated blood eight weeks or less before their estimated dates of seroconversion and may have been infectious (minimum rate 26/5831 (4.5/1000 potentially infected units)). Estimated incidence of infection in repeat donors was 1.2-2.5%. Laboratory test insensitivity would result in an estimated 1.1/1000 false negative units from first time donors and 0.2/1000 units from regular donors. The overall rate of potentially infected units (all donors, seroconversions, and errors) was estimated at 5.4-10.6/1000. CONCLUSIONS--The risk of HIV infection from a single unit of blood remains substantial (5.4-10.6/1000 units). To prevent infection from blood transfusion in areas of high incidence and prevalence of HIV all but absolutely essential transfusions should be avoided, and donors with low incidence of HIV infection should be selected.     

Synchronization of estrus in suckled postpartum beef cows with melengestrol acetate, 48-hour calf removal and PGF2alpha

One hundred and sixty-five suckled postpartum beef cows were utilized to evaluate the effectiveness of 2 estrus synchronization systems for the initiation and synchronization of estrus. The treatment groups consisted of 1) melengestrol acetate (MGA)-PGF2alpha (cows were given 0.5 mg MGA/head/day for 14 d with 25 mg PGF2alpha injected 17 d after the last day of MGA administration); 2) MGA-48-h calf removal (CR)-PGF2alpha (cows were given 0.5 mg MGA/head/day for 14 d with 48-h calf removal starting on the second day after completion of the MGA regimen plus 25 mg PGF2alpha administered 17 d after the last day of MGA); and 3) unsynchronized controls. Cows were assigned to treatments by the numbers of days post partum, body condition, age, and breed of sire. The cows were observed for estrus at 12-h intervals for 5 d after PGF2alpha administration and were artificially inseminated 12 to 18 h after the observed estrus. Both the MGA-PGF2alpha and MGA-CR-PGF2alpha treatments (64.8 and 61.8%) had greater (P < 0.05) 5-d estrus rates than the control treatments (34.5%). The synchronized pregnancy rate was greater (P < 0.05) for the MGA-CR-PGF2alpha than the control treatment.(52.7 vs 30.9%, respectively). The MGA-CR-PGF2alpha cows had a higher 25-d pregnancy rate than either the MGA-PGF2alpha (P < 0.05) or control cows (P < 0.08). Of the anestrous cows at the beginning of treatment, more MGA-CR-PGF2alpha (P = 0.1) and MGA-PGF2alpha cows were cyclic posttreatment than control cows (58.7 and 55.1 vs 44.7%, respectively), suggesting that treatment initiated estrous cycles in only a small number of the anestrous cows. Both MGA-PGF2alpha and MGA-CR-PGF2alpha treatments appear to be effective methods of synchronizing estrus in suckled postpartum beef cows. However, MGA-CR-PGF2alpha was more effective in establishing pregnancy earlier in the breeding season than MGA-PGF2alpha.     

Plasma arginine and ornithine levels and selected enzyme activities in uremic rats fed various amounts of arginine

Rats weighing 100 g were made chronically uremic by partial left renal artery ligation and contralateral nephrectomy. Rats with urea clearances below 0.30 ml/min and sham-operated controls were pair-fed arginine-free diets, diets containing normal amounts of arginine or diets with high levels of arginine. After 4 to 8 weeks, rats were killed and plasma levels of arginine, ornithine and lysine were measured. In addition, activities of various urea cycle enzymes in liver and kidney and renal transamidinase were determined. Plasma amino acid levels and enzyme activities of the urea cycle remained constant in control rats fed diets differing in arginine content. However, renal transamidinase activity was elevated in control rats fed arginine-free diets. In plasma of uremic as compared with control rats, arginine levels varied with the arginine intake, and lysine levels were elevated when arginine supplements were fed. With all diets, plasma ornithine remained constant in uremic rats at slightly but not significantly increased levels. Hepatic carbamoyl phosphate synthetase activity and renal arginine synthetase activity were reduced in uremic as compared to control rats. Renal transamidinase activity, expressed per g of kidney, was elevated in uremic rats with all diets except arginine-free. When amino acid diets were fed, hepatic arginase activity was higher in uremic rats and this increase was enhanced by arginine-free diets. Other enzyme activities in uremic rats were not affected by the amount of arginine in the diet.     

Complications of Antiretroviral Therapy Initiation in Hospitalised Patients with HIV-Associated Tuberculosis

Background

HIV-associated tuberculosis is a common coinfection in Sub-Saharan Africa, which causes high morbidity and mortality. A sub-set of HIV-associated tuberculosis patients require prolonged hospital admission, during which antiretroviral therapy initiation may be required. The aim of this study was to document the causes of clinical deterioration of hospitalised patients with HIV-associated tuberculosis starting antiretroviral therapy in order to inform healthcare practice in low- to middle-income countries.

Methods

Prospective, observational cohort study of adult inpatients with HIV-associated tuberculosis starting antiretroviral therapy in a dedicated tuberculosis hospital in Cape Town, South Africa. Causes of clinical deterioration and outcome were recorded in the first 12 weeks of antiretroviral therapy. Patients with rifampicin-resistant tuberculosis were excluded.

Results

Between May 2009 and November 2010, 112 patients (60% female), with a median age of 32 years were enrolled. At baseline the median CD4 count was 55 cells/mm³ (IQR 31–106) and HIV viral load 5.6 log copies/mL. All patients had significant comorbidity: 82% were bed-bound, 65% had disseminated tuberculosis and 27% had central nervous system tuberculosis. Seventy six patients (68%) developed 144 clinical events after starting antiretroviral therapy. TB-IRIS, hospital-acquired infections and significant drug toxicities occurred in 42%, 20.5% and 15% of patients respectively. A new opportunistic disease occurred in 15% of patients and a thromboembolic event in 8%. Mortality during the 12 week period was 10.6%.

Conclusions

High rates of TB-IRIS, hospital-acquired infections and drug toxicities complicate the course of patients with HIV-associated tuberculosis starting antiretroviral therapy in hospital. Despite the high morbidity, mortality was relatively low. Careful clinical management and adequate resources are needed in hospitalised HIV-TB patients in the 1^st three months following ART initiation.     

Use of passive radio frequency identification technologies to monitor nest usage in the northern carmine bee‐eater (Merops n. nubicus)

The use of radio frequency identification (RFID) technology is common in animal‐monitoring applications in the wild and in zoological and agricultural settings. RFID is used to track animals and to collect information about movements and other behaviors, as well as to automate or improve husbandry. Disney's Animal Kingdom® uses passive RFID technology to monitor nest usage by a breeding colony of northern carmine bee‐eaters. We implemented RFID technologies in various equipment configurations, initially deploying low‐frequency (LF) 125 kHz RFID and later changing to high‐frequency (HF) 13.56 MHz RFID technology, to monitor breeding behavior in the flock. We installed antennas connected to RFID readers at the entrances of nest tunnels to detect RFID transponders attached to leg bands as birds entered and exited tunnels. Both LF‐RFID and HF‐RFID systems allowed the characterization of nest visitation, including the timing of nest activity, breeding pair formation, identification of egg‐laying females, participation by nonresidents, and detection of nest disruptions. However, we collected a substantially larger volume of data using the increased bandwidth and polling speed inherent with HF‐RFID, which permitted tag capture of multiple birds simultaneously and resulted in fewer missed nest visits in comparison to LF‐RFID. Herein, we describe the evolution of the RFID setups used to monitor nest usage for more than 7 years, the types of data that can be gained using RFID at nests, and how we used these data to gain insights into carmine bee‐eater breeding behavior and improve husbandry.     

Seed dormancy,after-ripening and light requirements of four annual Asteraceae in south-western Australia

A dissected-leaved form of Ranunculus repens L. occurs in the temporary limestone lakes (turloughs) across the west of Ireland. Turloughs fill with groundwater for up to 8 months of the year. Under experimental conditions, these turlough populations demonstrated a higher rate of aerial and submerged photosynthesis than populations of the more typical broad-leaved ruderal form. The turlough populations also had higher rates of stomatal conductance and exhibited a higher stomatal index on the upper leaf surface and a lower index on the lower leaf surface than the ruderal populations. Neither population could utilize bicarbonate to any great extent, with rates of photosynthesis under submerged conditions being only 5 % of aerial rates. Respiration under submerged conditions was significantly higher in the turlough populations than in ruderal populations, and it is hypothesized that the more dissected leaf shape of the turlough population may have a thinner boundary layer and thus enhance gas exchange in submerged conditions.