Publishing HIV/AIDS behavioural science reports: An author's guide.

The purpose of this paper is to report on characteristics of journals that publish manuscripts in the HIV/AIDS behavioural science realm, with the goal of providing assistance to authors seeking to disseminate their work in the most appropriate outlet. Fifty journals who publish behavioural research on HIV/AIDS in English were identified through library and electronic searches. Although ten of the journals focused specifically on HIV/AIDS, the majority of journals are in related fields, including health psychology/behavioural medicine, sexual behaviour, substance abuse, public health/prevention or general medicine. Acceptance rates ranged from 8- 89% with a mean acceptance rate of 39%. Reported review times ranged from 1-12 months with three months the mode, while publication lag following acceptance averages six months. Acceptance rates were related to impact factors, with more selective journals evidencing higher impact factors. The variety of publication outlets available to authors of HIV/AIDS behavioral science studies creates ample opportunity for dissemination, as well as challenge for readers in discerning the quality of published work.

Chromatin packaging as an indicator of human sperm dysfunction.

PURPOSE: Understanding the causes of fertilization failure is an important research field in assisted reproductive programs. The present study aimed to evaluated the possible relationship between chromatin packaging quality (CMA3 staining) and (i) normal morphology and (ii) its ability to predict the functional integrity of spermatozoa in both in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) treatment programs. METHODS: Semen of 140 men from IVF and ICSI couples were analyzed for sperm concentration, motility, morphology, and chromatin packaging (CMA3). For CMA3 classification, two cutoff values were used, namely, 44.5% +/- 13 and 1 SD above the mean, i.e., 57.5% (rounded off to 60%). IVF and ICSI data were stratified using three basic cutoff values for CMA3 staining, namely, < 44%, > 44-60%, and > 60%. RESULTS: Based on CMA3 results patients were divided into four groups, namely, group A, < 44% CMA3 (n = 15, IVF); group B, > or = 44% and < 60% CMA3 (n = 39, IVF); group C, > or = 60% CMA3 (n = 45 IVF); and group D, > or = 60% CMA3 (n = 41 ICSI). During receiver operator characteristic analyses the estimated cutoff value for CMA3 staining, to distinguish between < 4% and > or = 4% morphology groups, was 60%. The area under the curve was 0.89, sensitivity of 75%, and specificity of 100%. When IVF rates of > 60% and < 60% were used, the optimal CMA3 value for prediction of fertilization success again was recorded at 60%. The area under the curve was 0.76, sensitivity of 81.5%, and specificity of 63.6%. CONCLUSIONS: Chromatin packaging assessments should be included as a complementary assay to the sequential diagnostic approach of the male-factor patients.

Tests of running performance do not predict subsequent spontaneous running in rats.

Rats of similar mass and genetic stock have up to a 50-fold difference in spontaneous daily running distance. However, the reasons for this large variability in spontaneous running distance are not known. This study examined whether tests of running performance predict subsequent spontaneous running distance in rats housed in individual running wheel cages. Long-Evans rats (n = 56) were randomly assigned to either a sedentary control group (C) or a group housed in specially designed wheel cages in which they were able to exercise spontaneously (ES). They then underwent a high-intensity running test (MAX), during which oxygen consumption was measured at a submaximal (VO2 submax) and maximal workload (VO2 max). The rats' submaximal running endurance (END) and maximal sprinting speed (SPRINT) were also tested on the treadmill. After 8 weeks the average spontaneous running distance of ES was 29.7 +/- 3.7 km.wk-1 (mean +/- SE), but ranged from 1.4 to 71.1 km.wk-1. Tests of running performance and oxygen consumption were repeated in both groups, followed by in situ measurements of muscle contractile properties and of citrate synthase activity in the skeletal muscle. None of the measurements of running performance or oxygen consumption during the initial tests conducted at the start of the experiment was related to subsequent average spontaneous running distance. After 8 weeks, the mean peak force generated by the electrically stimulated gastrocnemius/plantaris muscles was greater in ES than in C (746 +/- 89 vs. 455 +/- 28 mg, p < 0.005), but this difference was not related to spontaneous running distance. Conversely, citrate synthase activity of the soleus muscle after training was related to average spontaneous running distance (r = 0.92, p < 0.0004). Average spontaneous running distance was also related to MAX (r = 0.65, p < 0.002), END (r = 0.59, p < 0.0009), and SPRINT (r = 0.61, p < 0.0005) and was inversely related to running intensity (r = -0.66, p < 0.002) after 8 weeks of training. It can be concluded from this study that 1) spontaneous running distance in rats cannot be predicted by pretraining tests of running performance. Hence, low levels of spontaneous running activity in some rats are not explained by skeletal muscular and cardiovascular factors thought to determine running capacity, and 2) posttraining tests of running performance were proportionally related to total spontaneous running distance and muscle oxidative enzyme changes but not to the in situ contractile properties of the muscles.

Effects of medium-chain triglyceride ingestion on fuel metabolism and cycling performance.

On three occasions separated by 10 days, six endurance-trained cyclists rode for 2 h at 60% of peak O2 uptake and then performed a simulated 40-km time trial (T-trial). During the rides, the subjects ingested a total of 2 liters of a [U-14C]glucose-labeled beverage containing a random order of either 10% glucose [carbohydrate (CHO)], 4.3% medium-chain triglycerides (MCTs); or 10% glucose + 4.3% MCTs (CHO+MCT). Although replacing CHO with MCTs slowed the T-trials from 66.8 +/- 0.4 (SE) to 72.1 +/- 0.6 min (P < 0.001), adding MCTs to CHO improved the T-trials from 66.8 +/- 0.4 to 65.1 +/- 0.5 min (P < 0.05). Faster T-trials in the CHO+MCT trial than in the CHO trial were associated with increased final circulating concentrations of free fatty acids (0.58 +/- 0.09 vs. 0.36 +/- 0.06 mmol/l; P < 0.05) and ketones (1.51 +/- 0.25 vs. 0.51 +/- 0.07 mmol/l; P < 0.01) and decreased final circulating concentrations of glucose (5.2 +/- 0.2 vs. 6.3 +/- 0.3 mmol/l; P < 0.01) and lactate (1.9 +/- 0.4 vs. 3.7 +/- 0.5 mmol/l; P < 0.05). Adding MCTs to ingested CHO reduced total CHO oxidation rates from 14 +/- 1 to 10 +/- 1 mmol/min at 2 h and from 17 +/- 1 to 14 +/- 1 mmol/min in the T-trial (P < 0.01), without affecting the corresponding approximately 5 and approximately 7 mmol/min rates of [14C]glucose oxidation. These data suggest that MCT oxidation decreased the direct and/or indirect (via lactate) oxidation of muscle glycogen. A reduced reliance on CHO oxidation at a given O2 uptake is similar to an endurance-training effect, and that may explain the improved T-trial performances.

Running intensity as determined by heart rate is the same in fast and slow runners in both the 10- and 21-km races.

The aims of this study were to determine (1) whether running speed is directly proportional to heart rate (HR) during field testing and during 10- and 21-km races, and (2) whether running intensity, as estimated from HR measurements, differs in 10- and 21-km races and between slow and fast runners at those running distances. Male runners were divided into a fast (65-80 min for 21 km; n = 8) or slow (85-110 min for 21 km; n = 8) group. They then competed in 10- and 21-km races while wearing HR monitors. All subjects also ran in a field test in which HR was measured while they ran at predetermined speeds. The 10-km time was significantly less in the fast compared with the slow group (33:15 +/- 1:42 vs 40:07 +/- 3:01 min:s; mean +/- S.D.), as was 21-km time (74:19 +/- 4:30 vs 94:13 +/- 9:54 min:s) (P < 0.01). Despite the differences in running speed, the average running intensity (%HRmax) for the fast and slow groups in the 10-km race was 90 +/- 1 vs 89 +/- 3% and in the 21-km race 91 +/- 1 vs 89 +/- 2%, respectively. In addition, %HRmax was consistently lower in the field test at the comparative average running speeds sustained in the 10-km (P < 0.01) and 21-km (P < 0.001) races. Hence, factors in addition to work rate or running speed influence the HR response during competitive racing. This finding must be considered when running intensity for competitive events is prescribed on the basis of field testing performed under non-competitive conditions in fast and slow runners.

Anabolic-androgenic steroid increases running endurance in rats.

The study was designed to determine whether treatment with an anabolic-androgenic steroid enhances running performance in rats by increasing their freely chosen training distance. Forty male Long-Evans rats were randomly divided into either a sedentary control group or an exercising group caged in specially designed running wheels in which the rats were able to run spontaneously. After 4 wk, both groups were further subdivided into two groups receiving either 0.5-mg Durabolin (nandrolone phenylpropionate) (im) or 0.5-mg saline, every second day. After 8 wk, running distance was similar in both exercising groups. Rats receiving the anabolic-androgenic steroid ran 41% longer during the test of submaximal running endurance compared to the trained rats receiving saline (P < 0.05). Submaximal running endurance was not increased in sedentary rats receiving the anabolic-androgenic steroid. After 4 wk of training, the maximal sprinting speed increased by 29% in trained rats. There was no further increase in maximal sprinting speed after an additional 4 wk of training and treatment with either anabolic-androgenic steroid or saline treatment. Therefore, rats that train spontaneously while being treated with an anabolic-androgenic steroid had increased submaximal running endurance compared with trained rats treated with saline, despite the similar voluntary training distance and skeletal muscle oxidative capacity between the two groups. The mechanism by which treatment with an anabolic-androgenic steroid, combined with training, enhances submaximal running performance could not be identified and needs to be addressed in future studies.

Purification and partial characterization of an aldo-keto reductase from Saccharomyces cerevisiae.

A cytosolic aldo-keto reductase was purified from Saccharomyces cerevisiae ATCC 26602 to homogeneity by affinity chromatography, chromatofocusing, and hydroxylapatite chromatography. The relative molecular weights of the aldo-keto reductase as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and size exclusion chromatography were 36,800 and 35,000, respectively, indicating that the enzyme is monomeric. Amino acid composition and N-terminal sequence analysis revealed that the enzyme is closely related to the aldose reductases of xylose-fermenting yeasts and mammalian tissues. The enzyme was apparently immunologically unrelated to the aldose reductases of other xylose-fermenting yeasts. The aldo-keto reductase is NADPH specific and catalyzes the reduction of a variety of aldehydes. The best substrate for the enzyme is the aromatic aldehyde p-nitrobenzaldehyde (Km = 46 microM; kcat/Km = 52,100 s-1 M-1), whereas among the aldoses, DL-glyceraldehyde was the preferred substrate (Km = 1.44 mM; kcat/Km = 1,790 s-1 M-1). The enzyme failed to catalyze the reduction of menadione and p-benzoquinone, substrates for carbonyl reductase. The enzyme was inhibited only slightly by 2 mM sodium valproate and was activated by pyridoxal 5'-phosphate. The optimum pH of the enzyme is 5. These data indicate that the S. cerevisiae aldo-keto reductase is a monomeric NADPH-specific reductase with strong similarities to the aldose reductases.

Role of D-ribose as a cometabolite in D-xylose metabolism by Saccharomyces cerevisiae.

The influence of D-ribose as a cosubstrate on the uptake and metabolism of the non-growth substrate D-xylose by Saccharomyces cerevisiae ATCC 26602 was investigated. Xylose was taken up by means of low- and high-affinity glucose transport systems. In cells exposed for 2 days to a mixture of xylose and ribose, only the high-affinity system could be detected. Glucose strongly inhibited the transport of xylose by both systems. Starvation or exposure to either xylose or ribose resulted in inactivation of xylose transport, which did not occur in the presence of a mixture of ribose and xylose. A constitutive non-glucose-repressible NADPH2-dependent xylose reductase with a specific activity of ca. 5 mU/mg of protein that converted xylose to xylitol was present in a glucose-grown culture. No activity converting xylitol to xylulose or vice versa was found in crude extracts. Both xylose and ribose were converted to their corresponding polyols, xylitol and ribitol, as indicated by 13C nuclear magnetic resonance spectroscopy. Furthermore, ethanol was detected, and this implied that pathways for the complete catabolism of xylose and ribose exist. However, the NADPH2 required for the conversion of xylose to xylitol is apparently not supplied by the pentose phosphate pathway since the ethanol produced from D-[1-13C]xylose was labelled only in the C-2 position. Acetic acid was produced from ribose and may assist in the conversion of xylose to xylitol by cycling NADPH2.

D-xylose utilization by Saccharomyces cerevisiae.

Although it is generally accepted that Saccharomyces cerevisiae is unable to assimilate D-xylose, four strains were found to utilize xylose aerobically at different efficiencies in the presence of a mixture of substrates. The degree of D-xylose utilization by S. cerevisiae ATCC 26602 depended upon the presence of other substrates or yeast extract. The greatest amount of xylose (up to 69% over 7 d) was utilized when sugar substrates such as D-ribose were co-metabolized. Much lower degrees of utilization occurred with co-metabolism of organic acids, polyols or ethanol. A mixture of D-glucose, D-ribose, D-raffinose, glycerol and D-xylose resulted in greater xylose utilization than the presence of a single substrate and xylose. The absence of growth on a co-substrate alone did not prevent the utilization of xylose in its presence. Xylose was co-metabolized with ribose under anaerobic conditions but at a much slower rate than under aerobic conditions. When [14C]xylose was utilized in the presence of ribose under anaerobic conditions, the radioactive label was detected mainly in xylitol and not in the small amounts of ethanol produced. Under aerobic conditions the radioactive label was distributed between xylitol (91.3 +/- 0.8%), CO2 (2.6 +/- 2.3%) and biomass (1.7 +/- 0.6%). No other metabolic products were detected. Whereas most xylose was dissimilated rather than assimilated by S. cerevisiae, the organism apparently possesses a pathway which completely oxidizes xylose in the presence of another substrate.

The incidence of polyspermy during in vitro fertilisation. A study at the H. F. Verwoerd Hospital, Pretoria.

Results from 1249 in vitro-fertilised human oocytes were analysed to identify the incidence of polyspermy. In this study polyspermy occurred in 23 oocytes (1.8%). The effects of the various ovulation induction protocols employed, maturation of oocytes, incubation time before insemination and anaesthesia exposure were examined in order to identify a cause for polyspermy. Early diagnosis of polyspermy is important because the polyspermic embryo may appear morphologically normal at a later stage but should not be transferred since this nearly always results in a spontaneous abortion.

Possible radiation injury at Koeberg Nuclear Power Station. Organization of medical care.

Any injured patient from Koeberg Nuclear Power Station will be treated in the conventional manner as an acute surgical emergency; this has priority over decontamination. The ideal situation is decontamination at Koeberg before ambulance transferral to the Tygerberg Radiation Casualty Facility, but if this is not possible or complete, decontamination can be accomplished by a trained team in the unit. Teamwork is the essence at the place of injury, during transfer, in the decontamination area, in the operating theatre and during the postoperative phase. No surgical management is appropriate or complete without the very necessary guidance and advice from a physicist and the Advisory Group for Radiation Casualties.