The physiological consequences of acceleration during shuttle running.

This study examined the acceleration demands associated with changing direction and the subsequent physiological consequences of acceleration during running at 3 submaximal speeds. 10 male professional footballers completed four 600 m running bouts at 3 speeds (2.50, 3.25 & 4.00 m·s(-1)). Each bout was in the format of either: i) 3 laps of a 200 m track (CON), ii) ten 60 m shuttles (S60), iii) twenty 30 m shuttles (S30), or iv) thirty 20 m shuttles (S20). Peak heart rate (HRPEAK), blood lactate concentration (BLa) and RPE (Borg CR-10) were recorded for each bout. A single change of direction required 1.2, 1.5 and 2.0 s of acceleration at running speeds of 2.50, 3.25 and 4.00 m s(-1) respectively. An increase in time spent accelerating produced a linear increase in BLa (r=0.43-0.74) and RPE (r=0.81-0.93) at all speeds. Acceleration increases linearly with change of direction frequency during submaximal shuttle running. Increased time spent accelerating elicits proportional increases in perceived exertion, BLa and HRPEAK. The current study further underlines the need to consider acceleration when quantifying training load during activities involving numerous changes of direction.

Symptomatic benign breast disease and hormone replacement therapy.

The effect of hormone replacement therapy (HRT) on presentation and diagnoses of post-menopausal women has been examined by a retrospective review of patients presenting to a symptomatic Breast Clinic over a 5-year period. Sixty-seven post-menopausal women aged less than 65 years taking hormone replacement therapy for more than 6 months were compared with 144 post-menopausal women aged less than 65 years not taking hormone replacement therapy. There was no difference in the pattern of presentation, rate of intervention or final diagnoses between these two groups. HRT does not appear to effect the pattern of presentation of benign breast disease in post-menopausal women.

Bone mineralization in children and adolescents with a milk allergy.

To evaluate the correlation between dietary calcium intake and mineralization of the immature skeleton 55 children and adolescents aged 5-14 years (mean, 9.5 years) with a positive radioallergosorbent test (RAST) for serum antibodies to cow's milk protein were evaluated. Bone mineral density (BMD) in the lumbar spine and proximal femurs were measured by dual energy X-ray absorptiometry. BMD at each site for each subject was converted to an age-adjusted Z score based on our own series of 95 normal pediatric controls. Calcium intake was determined using a detailed food frequency questionnaire administered by a nutritionist during a 30-40-min interview. Dietary adjustments to the condition varied and resulted in a wide range of calcium intakes. Calcium supplements were taken by 22% of the subjects and were included in the determination of daily calcium intake. The group of 55 subjects was divided into quartiles based on calcium intake (mean +/- S.E mg calcium/day): Group 1, 409 +/- 21, Group 2, 663 +/- 16, Group 3, 950 +/- 32, Group 4, 1437 +/- 124. Bone density Z scores in the proximal femur serially increased across the calcium intake groups (mean +/- S.E.): Group 1, -0.16 +/- 0.31; Group 2, 0.05 +/- 0.33; Group 3, 0.44 +/- 0.24; Group 4, 0.79 +/- 0.41 (P = 0.03). A similar pattern was found with lumbar spine BMD Z scores: Group 1, -0.16 +/- 0.27; Group 2, 0.10 +/- 0.21; Group 3, 0.18 +/- 0.20; Group 4, 0.30 +/- 0.25 (P = 0.05). These data add further to the evidence that dietary calcium intake is important for optimal mineralization of the growing skeleton.

Prevalence of late-onset tibia vara.

We wished to determine the prevalence of late-onset tibia vara in an at-risk population. From a group of 1,117 boys aged 13-19 years, we selected all those who weighed at least 210 pounds. The 140 boys (80 black, 60 white) who met this inclusion criterion were examined for varus alignment. Radiographs of the seven boys who screened positive showed that two boys had late-onset tibia vara. Both boys were black and weighed > 280 pounds. The prevalence of late-onset tibia vara in this obese adolescent black male population was 2.5% (two of 80 boys). Recently, the number of reported cases of late-onset tibia vara has increased dramatically probably owing to an increase in the prevalence of morbid obesity.

Enhanced inactivation of bacterial lipases and proteinases in whole milk by a modified ultra high temperature treatment.

Cultures of Pseudomonas spp. strains P10, P12 and P15 grown in whole milk which contained approximately 1 x 10(8) viable bacteria ml-1 demonstrated near linear increases in the concentration of short-chain free fatty acids and trichloroacetic acid soluble free amino groups at 20 degrees C, following either ultra high temperature (UHT) treatment (140 degrees C for 5 s) or dual heat treatments (140 degrees C followed by either 57, 60 or 65 degrees C). The dual heat treatments reduced the rates of lipolysis and proteolysis compared to the UHT treatment by up to 25-fold. The dual heat treatment utilizing 60 degrees C for 5 min also effectively limited both lipase and proteinase activities in raw milk culture samples which had contained either 6 x 10(6), 5 x 10(7) or 1 x 10(8) viable bacteria ml-1. In this system enzyme activities were reduced by up to 10-fold following dual heat treatment compared to UHT treatment alone.

A modified ultra high temperature treatment for reducing microbial lipolysis in stored milk.

Cultures of Pseudomonas P46 grown in whole milk to contain approximately 2 X 10(7) or 1 X 10(8) viable cells ml-1 before ultra high temperature (UHT) treatment (140 degrees C for 5 s) demonstrated near linear increases in the concentration of short-chain free fatty acids (FFA) during storage at 20 degrees C. However with 5 X 10(6) cells ml-1 before UHT heat treatment there was no detectable increase in these FFA levels over a 6-month storage period. A novel heat treatment (140 degrees C for 5 s followed by 60 degrees C for 5 min) reduced the rate of production of volatile FFA to less than 10% of the rates achieved after the normal UHT treatment.

Physiological and microbiological changes in the abomasum of sheep infected with large doses of Haemonchus contortus.

The pH, PO2 and the number of viable bacteria per ml of abomasal fluid were recorded before and after administering large doses of infective larvae of H. contortus to sheep. Highly significant increases were observed in the pH, in numbers of viable bacteria and in the proportion of oxygen-sensitive bacteria in the abomasal fluid during the first 10 to 14 days of infection. At the same time a decrease in the abomasal fluid PO2 was recorded. Subsequently a slow recovery of pH, PO2 and bacterial numbers to pre-infection values ensued. The microbiological and physiological changes occurring in the abomasum of sheep after infection with H. contortus are discussed with reference to these results.

Common and individually specific chromosomal characteristics of cultured human melanoma.

Since individual chromosomes can be accurately identified by new banding techniques, atebrin fluorescence was used for chromosome analysis in six cell lines and two primary outgrowths derived from human malignant melanoma. Gross aneuploidy was seen in all specimens, but each culture contained at least 1 distinctive marker chromosome specific for that cell line in 87 to 100% of metaphases. One of the primary explants contained a marker that was demonstrable in fresh tissue and persisted through 2 weeks of culture. The same marker was found in all metaphases from 2 different metastases, but skin fibroblasts from the same patient had a normal chromosome complement. No common marker for human melanoma was found, but in 6 of the 8 cultures the most frequently found marker was formed by a brightly banded chromatid addition. Relative polysomy for Chromosome 7 was found in 7 of the 8 cultures and, for Chromosome 22, in 8 of the 8 cultures. The frequency of polysomy of Chromosomes 7 and 22 was significant at the 5% level.