Repeated exposure of rats to JP-4 vapor induces changes in neurobehavioral capacity and 5-HT/5-HIAA levels.

Thirty-two Sprague-Dawley rats were exposed for 6 h/d for 14 consecutive days to JP-4 jet fuel vapor (2 mg/L) or room air control conditions. Following a 14- or 60-d recovery period, rats completed a battery of 8 tests selected from the Navy Neurobehavioral Toxicity Assessment Battery (NTAB) to evaluate changes in performance capacity. Exposure to JP-4 vapor resulted in significant changes in neurobehavioral capacity on several tests that varied as a function of the duration of the recovery period. Rats were evaluated for major neurotransmitter and metabolite levels in five brain regions and in the blood serum. Levels of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were shown to be significantly elevated in several brain regions as well as in the blood serum in the vapor-exposed groups. Results of the rat study are compared to previously reported neurobehavioral evaluations of European manufacturing personnel exposed chronically to jet fuel vapor.

Caloric and nitrogen balances as predictors of nutritional outcome in patients with burns.

Measurement of energy expenditure with indirect calorimetry allows determination of caloric balance. The present study was done to determine the predictive value of caloric and nitrogen balances for nutritional outcome. Energy expenditure was obtained weekly and interpolated between measurements for daily caloric balance. Nitrogen balance was obtained weekly. Because nitrogen output fluctuated, interpolation of daily values was not possible. Nutritional outcome was defined by whether body weight was lost or maintained and by levels of visceral proteins (albumin, prealbumin, and transferrin). The study group included 12 patients with 7% to 82.5% total body surface area burns. Eleven patients survived their burn injuries, and one died of congestive heart failure at 38 days, after her burn wounds had healed. Nine patients had good nutritional outcomes (group 1) and three had poor nutritional outcomes (group 2) (including the one who died). Nitrogen balance was 1.3 +/- 1.0 gm/day in group 1 and 4.5 +/- 1.7 gm/day in group 2 (mean +/- SEM; p > 0.10). Caloric balance was 515 +/- 130 kcal/day in group 1 and -667 +/- 140 in group 2 (p < 0.001). Caloric balance was significantly different between the two groups, whereas nitrogen balance was not. Caloric intake correlated positively with nitrogen intake (r = 0.92). Nitrogen intake was 16% of total caloric intake. Nitrogen intake from blood products was appreciable and averaged 15% of total nitrogen intake (range, 0% to 47%); 11.3 +/- 1.6 gm/day in group 1 and 14.8 +/- 3 gm/day in group 2 (p > 0.10).(ABSTRACT TRUNCATED AT 250 WORDS)

Buffalo and Bali cattle--exploiting their reproductive behaviour and physiology.

Water buffalo (Bubalus bubalis) and Bali cattle (Bos sondaicus) occupy production niches in much of the developing world's agricultural systems which in the developed world are occupied by Bos indicus and Bos taurus. Both the former species are better-adapted to these environments and systems. Both depend on population survival strategies different from each other's and from those of B. indicus and B. taurus. Water buffalo rely on longevity and late sexual maturity, while Bali cattle rely on high conception rates and sacrifice of juveniles when the population is under stress. Knowledge of these different strategies will help in formulation of management strategies for maximising nett reproductive rates. This paper briefly describes each species, reviews its survival strategies and summarises the available data on the reproductive characteristics of each.

Spermatogenesis in Bali cattle (Bos sondaicus) and hybrids with Bos indicus and Bos taurus.

Semen quality, testis size and efficiency of sperm production in Bali cattle (Bos sondaicus) and hybrids with Bos indicus and Bos taurus were determined. Mean (+/- SEM) daily sperm production per gram of testis parenchyma (DSPG) in six purebred Bali bulls was 12.2 +/- 0.7 x 10(6). F1 B sondaicus cross B taurus bulls and F1 B sondaicus cross B indicus bulls were sterile. Spermatogenesis was arrested at the late primary spermatocyte stage. In 11 B sondaicus cross B indicus crosses, mean DSPG was lower than in the purebred B sondaicus, although four (one 1/4 B sondaicus, one 3/4 B sondaicus, one 5/8 B sondaicus inter se and one 3/8 B sondaicus inter se) exhibited DSPG levels similar to the foundation stock. Semen from those crossbreeds which exhibited complete spermatogenesis was more variable in terms of spermatozoal concentration, percentage of spermatozoa exhibiting progressive motility and levels of spermatozoal abnormalities. In crossbreeds where sperm production was reduced or absent, there was seminiferous epithelial dysfunction, manifested as an increased frequency of degenerative late pachytene and diplotene primary spermatocytes and germinal cells occurring later in the cycle, or in extreme cases, as complete arrest of spermatogenesis at the late primary spermatocyte stage.

The cycle of the seminiferous epithelium in Bali cattle (Bos sondaicus).

The duration of the cycle of the seminiferous epithelium in 5 mature Bali bulls was 11.75 days (standard error of estimate 0.52 days). The relative frequencies of the stages of the cycle of the seminiferous epithelium (morphological classification) of Bali cattle differed from other cattle and buffalo in that there were lower frequencies of Stage 1 and 2 tubules, and higher frequencies of Stage 3, 6 and 7 tubules.

The development of puberty and sexual maturity in the Australian Swamp buffalo bull.

Testes from 47 juvenile Swamp buffalo bulls were examined for puberty and sexual maturity histologically and daily sperm production per gram of testis parenchyma was determined by enumeration of elongated spermatids in homogenates of testis parenchyma. Puberty was defined as the attainment of a daily sperm production per gram of testis parenchyma>0.5x10(6). In most bulls, puberty is attained by 24 mo of age, when scrotal circumference (SC) is approximately 16 cm, and liveweight exceeds 135 kg. Sexual maturity was defined as the attainment of adult levels of daily sperm production per gram of testis parenchyma (14x10(6)). In most bulls, this occurs at 30 to 33 mo of age, when SC is in the 17-to 20-cm range, and liveweight generally exceeds 250 kg. There was marked individual variation in age, liveweight and SC at both puberty and sexual maturity.

Brahman bull fertility in a north Australian rangeland herd.

Low and variable bull fertility was identified as a constraint on reproductive rates in beef cattle grazed in an extensive, multiple sire mating regimen on Mount Bundey station in the Darwin pastoral district of northwestern Australia. Erratic conception patterns were attributed to a high proportion of bulls with low breeding soundness evaluation scores (BSE), a high proportion of aged bulls (40%>8 yr), and to running bulls of mixed age groups. Liveweight, scrotal circumference (SC) and age were positively correlated. An experiment was subsequently designed to investigate the ability of a number of bull measurements to predict fertility in an extensively-managed, multiple-sire mating system. Blood typing was used to match calves to sires. It proved to be an accurate and useful technique which successfully identified the parentage of 94% of calves examined. Single measurements of serum testosterone after administration of gonadotrophin-releasing hormone (GnRH) were not correlated with fertility. However six of the seven most fertile bulls exhibited high peak serum testosterone levels in summer, and lower levels in the winter. In contrast, the less fertile bulls did not exhibit seasonal variation in GnRH-induced serum testosterone levels. Social dominance ratio was weakly related to fertility (r=0.51: P<0.05). BSE (r=0.51: P<0.05) and SC (r=0.49: P<0.05) prior to, but not subsequent to, mating were correlated with bull fertility. Under the conditions of this experiment, a bull to cow ratio of 1:20 was excessive for bulls with a satisfactory BSE score.

The effects of capture stress on testis function in the Australian Swamp buffalo (Bubalus bubalis ).

Capture stress significantly affected the cellular composition and function of the testis and epididymis of feral Swamp buffalo bulls. There was an initial acute drop in the population of elongated spermatids, round spermatids and late primary spermatocytes, and subsequently, a more gradual decline in the early elongated spermatid and late primary spermatocyte populations as the duration of the stress increased. Sertoli cell numbers were unaffected. The most marked effect was on the early elongated spermatid population, which was approximately halved in the stressed bulls. Testis parencyhmal weight was approximately 50% lower in stressed bulls. Affected bulls would undoubtedly be at least temporarily subfertile or infertile. The long-term prognosis on the fertility of such bulls is not known. Possible mechanisms involved in the pathogenesis of the syndrome are considered in this study.

The cycle of the seminiferous epithelium in the Australian Swamp buffalo.

The relative frequencies of stages and substages of the Swamp buffalo seminiferous epithelium were determined using a morphological classification. Duration of one cycle of the seminiferous epithelium was determined from radiolabelling studies using tritiated thymidine. Mean (+/-SD) duration of the cyle of the seminiferous epithelium of five Swamp buffalo was 8.74 +/- 0.18 d. Mean (+/-SEM) relative frequencies of stages and substages of the seminiferous epithelial cycle in ten bulls were Stage 1a, 7.27 +/- 0.72; Stage 1b, 8.11 +/- 0.85; Stage 1c, 8.54 +/- 1.13; Stage 2a, 5.9 +/- 0.79; Stage 2b, 7.49 +/- 0.78; Stage 3a, 9.05 +/- 0.66; Stage 3b, 9.69 +/- 1.11; Stage 4a, 5.04 +/- 0.44; Stage 4b, 4.8 +/- 0.69; Stage 5, 1.86 +/- 0.23; Stage 6, 8.81 +/- 0.84; Stage 7, 10.64 +/- 1.2; Stage 8a, 6.87 +/- 0.96; and Stage 8b, 5.93 +/- 0.72.

The effects of acute sleep deprivation during residency training.

Verbal and symbol concentration, learning, problem solving, clear thinking, manual skills, and memory were tested in 42 surgical residents to assess the effects of acute sleep deprivation on specific neuropsychological parameters. A series of eight neuropsychological tests--digit symbols, digit vigilance, story memory, trail making, PASAT, Raven matrices, delayed story, and pegboard--and a questionnaire on mood states were completed by the residents both when fatigued (less than 4 hours of sleep: mean, 2.0 +/- 1.5 hours) and when rested (more than 4 hours of sleep: mean, 6.5 +/- 1.0 hours), with at least 7 days between tests. In order to eliminate the effects of learning from the first test series, randomization of residents was performed so that one half were first evaluated when rested and one half when fatigued. ANOVA, multiple regression analysis, and the Student t test were used to assess differences. In the acute sleep-deprived state, residents were less vigorous and more fatigued, depressed, tense, confused, and angry (p less than 0.05) than they were in rested state. Despite these changes in mood, however, the responses on all of the functional tests were no different statistically in those who were rested and those who were fatigued (even in those with less than 2 hours' sleep). We conclude that acute sleep deprivation of less than 4 hours alters mood state but does not change performance in test situations in which concentration, clear thinking, and problem solving are important.

Prevalence of bovine venereal disease in the Victoria River District of the Northern Territory: likely economic effects and practicable control measures.

Area prevalences of bovine Campylobacteriosis and Trichomoniasis in the Victoria River District (VRD) of the Northern Territory were determined by a survey of bulls. Eighty-seven percent of herds were infected with Campylobacteriosis and 65.6 percent were infected with Trichomoniasis. The levels of infection recorded are likely to be causing significant reductions in reproductive rates. Control of Campylobacteriosis is unlikely to be practicable on a district basis, but in some herds it may be possible to implement control measures in select groups subject to good stock control. Trichomoniasis control measures are generally not implementable in the VRD management situation. Computer modelling suggests that control measures are unlikely to be profitable in commercial herds. There is a need for field investigations to confirm this.

Distribution of Cysticercus bovis in lightly infected young cattle.

Sixty-seven young cattle grazed on a sewage farm since birth were slaughtered and the carcases finely dissected in search of Cysticercus bovis. Forty-seven (70%) were infected, but only 49% of infected cattle had cysts in tissues considered to be sites of predilection and only 19.8% of all cysts found were located in these sites. Most of the remaining cysts were distributed randomly throughout the masculature.

Transient insulin increase in reactive hypoglycemia in obese and non-obese subjects.

(1). Insulin levels at the moment of glucose-induced reactive hypoglycemia have been compared with zero-hour insulin levels in 108 subjects in whom the blood glucose had decreased to 50 mg percent or less (50 to 31 mg) at the third, fourth, or fifth hour in the course of an oral glucose tolerance test (1.75 g/kg of body weight). (2). Of the 47 obese subjects, insulin levels at the time of the reactive hypoglycemia were inappropriately high, ie exceeded the fasting insulin level by 20 uU/ml or more in 38 percent and by 40 microunits/ml or higher in 26 percent of the tests. (3). In 61 non-obese subjects, employing the same criteria, inappropriately high insulinemia at the time of reactive hypoglycemia was recorded with about the same frequency. (4). In each instance of reactive hypoglycemia of 50 mg percent or less with concomitant insulin levels above the starting value to the degree stipulated, the so-termed inappropriate hyperinsulinemia was transient. In other words, judging by levels preceding and/or following the reactive hypoglycemia, insulin titers were decreasing and hence, the inappropriately high insulin level at the moment of hypoglycemia represented a lag phenomenon. (5). The above data suggest that insulin levels elevated above the starting value may play a role in reactive hypoglycemia. In subjects with insulin levels at the time of reactive hypoglycemia equal to or below the starting value, the low blood glucose level cannot be attributed to insulin. In such instances, delay or lag in hepatic glucose output and/or counter-regulatory responses probably play the dominant or sole role in the reactive hypoglycemia.

Unresponsiveness to exogenous TSH in obesity.

(1). Assessment of thyroidal and other indices in 275 instances of obesity with body weight excesses up to 200 percent or more of the ideal revealed absent thyroidal I131 uptake responses to TSH in about one out of five patients. Moreover, basal thyroidal I131 uptake of 10 percent or less, prolongation of ankle reflex time, or high levels of serum cholesterol were present in a minority. Also, occasional instances of unduly elevated serum TSH titers were found. Some of the indices deviated from normal more often with the greater excesses of body weight or with increased age. (2). These findings are consonant with a hypothesis that routine thyroidal or related indices are sporadically abnormal in massive obesity almost always without overt hypothyroidism or myxedema, that total unresponsiveness to exogenous TSH is surprisingly frequent, and that such unresponsiveness represents an unexplained endocrine anomaly in association with gross overweight. (3). Our data suggest that some obese persons are not able to respond to exogenous TSH, nor, presumably, to increases of endogenous TSH. This could result in an economy of caloric expenditure and play a contributory role in the genesis or the perpetuation of the obesity.