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Biomedical subjects

J S Baker

Publications and source records attributed to J S Baker.

At least 19 recordsLinked to original sources
PubMed2006

Development of a healthy biscuit: an alternative approach to biscuit manufacture.

OBJECTIVE: Obesity (BMI >30) and related health problems, including coronary heart disease (CHD), is without question a public health concern. The purpose of this study was to modify a traditional biscuit by the addition of vitamin B6, vitamin B12, Folic Acid, Vitamin C and Prebiotic fibre, while reducing salt and sugar. DESIGN: Development and commercial manufacture of the functional biscuit was carried out in collaboration with a well known and respected biscuit manufacturer of International reputation. The raw materials traditionally referred to as essential in biscuit manufacture, i.e. sugar and fat, were targeted for removal or reduction. In addition, salt was completely removed from the recipe. PARTICIPANTS: University students of both sexes (n = 25) agreed to act as subjects for the study. Ethical approval for the study was granted by the University ethics committee. The test was conducted as a single blind crossover design, and the modified and traditional biscuits were presented to the subjects under the same experimental conditions in a random fashion. RESULTS: No difference was observed between the original and the modified product for taste and consistency (P > 0.05). The modified biscuit was acceptable to the consumer in terms of eating quality, flavour and colour. Commercial acceptability was therefore established. CONCLUSION: This study has confirmed that traditional high-fat and high-sugar biscuits which are not associated with healthy diets by most consumers can be modified to produce a healthy alternative that can be manufactured under strict commercial conditions.

Cross-Over Studies↗
PubMed2006

Homocysteine induced cardiovascular events: a consequence of long term anabolic-androgenic steroid (AAS) abuse.

OBJECTIVES: The long term effects (>20 years) of anabolic-androgenic steroid (AAS) use on plasma concentrations of homocysteine (HCY), folate, testosterone, sex hormone binding globulin (SHBG), free androgen index, urea, creatinine, haematocrit (HCT), vitamin B12, and urinary testosterone/epitestosterone (T/E) ratio, were examined in a cohort of self-prescribing bodybuilders. METHODS: Subjects (n = 40) were divided into four distinct groups: (1) AAS users still using AAS (SU; n = 10); (2) AAS users abstinent from AAS administration for 3 months (SA; n = 10); (3) non-drug using bodybuilding controls (BC; n = 10); and (4) sedentary male controls (SC; n = 10). RESULTS: HCY levels were significantly higher in SU compared with BC and SC (p<0.01), and with SA (p<0.05). Fat free mass was significantly higher in both groups of AAS users (p<0.01). Daily energy intake (kJ) and daily protein intake (g/day) were significantly higher in SU and SA (p<0.05) compared with BC and SC, but were unlikely to be responsible for the observed HCY increases. HCT concentrations were significantly higher in the SU group (p<0.01). A significant linear inverse relationship was observed in the SU group between SHBG and HCY (r = -0.828, p<0.01), indicating a possible influence of the sex hormones in determining HCY levels. CONCLUSIONS: With mounting evidence linking AAS to adverse effects on some clotting factors, the significantly higher levels of HCY and HCT observed in the SU group suggest long term AAS users have increased risk of future thromboembolic events.

Adult↗
PubMed2006

Steroid and prescription medicine abuse in the health and fitness community: A regional study.

BACKGROUND: The purpose of this study was to identify the prevalence of abuse of certain prescription medicines (POM) amongst health club attendees. The non-therapeutic use of such medicines has previously been considered to be restricted to the professional athlete. METHODS: In the summer of 2005, health club users in the South Wales area were given questionnaires and asked to return them in a stamped, addressed envelope. Anonymity of the respondents was assured. RESULTS: From the distribution of 210 questionnaires, the response rate was 69.5% (146 questionnaires). The mean age of the sample was 33.6+/-6.7 years (range 15-72 years). Anabolic-androgenic steroid (AAS) use is prominent amongst recreational gym users in this regional sample, with 70% (102 individuals) reporting AAS use, 65.8% (96 individuals) of whom were currently still using. Some 7% of respondents (10 individuals) were female and they also reported taking medication. This research demonstrated an enormous increase in the use of growth hormone (24%), insulin (14%), and tamoxifen (22%), with smaller increases in other drugs. CONCLUSION: Drug users were from all levels of society and reported various physiological and psychological side effects from their use. The present study indicated that the most used medicine/drug from less than reputable sources was still AAS but that, as a consequence of the internet revolution, they were being caught up by the more expensive designer drugs, particularly growth hormone. Physicians and medical personnel must become aware that the use of AAS and other prescription medicines is on the increase and appears to be predominantly used for cosmetic reasons.

Journal Article↗
PubMed2005

The repeatability and criterion related validity of the 20 m multistage fitness test as a predictor of maximal oxygen uptake in active young men.

OBJECTIVE: To investigate the repeatability and criterion related validity of the 20 m multistage fitness test (MFT) for predicting maximal oxygen uptake (Vo(2max)) in active young men. METHODS: Data were gathered from two phases using 30 subjects (x+/-s; age = 21.8+/-3.6 years, mass = 76.9+/-10.7 kg, stature = 1.76+/-0.05 m). MFT repeatability was investigated in phase 1 where 21 subjects performed the test twice. The MFT criterion validity to predict Vo(2max) was investigated in phase 2 where 30 subjects performed a continuous incremental laboratory test to volitional exhaustion to determine Vo(2max) and the MFT. RESULTS: Phase 1 showed non-significant bias between the two applications of the MFT (x(diff)+/-s(diff) = -0.4+/-1.4 ml kg(-1) min(-1); t = -1.37, p = 0.190) with 95% limits of agreement (LoA) +/-2.7 ml kg(-1) min(-1) and heteroscedasticity 0.223 (p = 0.330). Log transformation of these data reduced heteroscedasticity to 0.056 (p = 0.808) with bias -0.007+/-0.025 (t = -1.35, p = 0.190) and LoA+/-0.049. Antilogs gave a mean bias on the ratio scale of 0.993 and random error (ratio limits) x/divided by 1.050. Phase 2 showed that the MFT significantly underpredicted Vo(2max) (x(diff)+/-s(diff) = 1.8+/-3.2 ml kg(-1) min(-1); t = 3.10, p = 0.004). LoA were +/-6.3 ml kg(-1) min(-1) and heteroscedasticity 0.084 (p = 0.658). Log transformation reduced heteroscedasticity to -0.045 (p = 0.814) with LoA+/-0.110. The significant systematic bias was not eliminated (x(diff)+/-s(diff) = 0.033+/-0.056; t = 3.20, p = 0.003). Antilogs gave a mean bias of 1.034 with random error x/divided by 1.116. CONCLUSIONS: These findings lend support to previous investigations of the MFT by identifying that in the population assessed it provides results that are repeatable but it routinely underestimates Vo(2max) when compared to laboratory determinations. Unlike previous findings, however, these results show that when applying an arguably more appropriate analysis method, the MFT does not provide valid predictions of Vo(2max).

Adolescent↗
PubMed2004

A simple multistage field test for the prediction of anaerobic capacity in female games players.

OBJECTIVE: To establish the validity of a 15 m multistage shuttle run test (MSRT) as a predictor of anaerobic capacity (expressed as mean power output (MPO) from the 30 second Wingate anaerobic test (WAnT)) in female university standard games players. METHODS: Data came from three phases using a total of 72 players (mean (SD) age 20.3 (1.5) years, body mass 64.9 (8.8) kg, and stature 1.67 (0.04) m). The repeatability of the MSRT was assessed in phase 1 by applying 95% limits of agreement (LoA) to the test and retest results from a random sample of 20 players. In phase 2, linear relations between MPO and performance on the MSRT were investigated in a random sample of 36 players. As a result, a calibration model (Y = a + bX) was developed and cross validated in phase 3, in which the remaining 36 players performed both the WAnT and the MSRT. Time (seconds) to volitional exhaustion/disqualification from the MSRT was substituted into the calibration model from which MPO was predicted. The agreement between MPO predicted and MPO measured from the WAnT was quantified using LoA. RESULTS: Insignificant bias between repeat applications of the MSRT (mean(diff) (SD(diff)) = 1.0 (3.5) seconds (4 (14) m), t = 1.23, p = 0.230) was found from phase 1. Data were homoscedastic (r = 0.061, p = 0.799) with LoA +/- 6.9 seconds (+/- 27 m). In phase 2 the strongest correlation was between MPO (W/kg(0.67)) and time to volitional exhaustion/disqualification on the MSRT; r = 0.715 (r(2) = 51.1%, p = 0.0005). As a result, the calibration model developed was: MPO (W/kg(0.67)) = 12.5 + (0.2 x time (seconds)) with a standard error of prediction of 2.1 W/kg(0.67). The cross validation in phase 3 showed insignificant bias between measured and predicted MPO (mean(diff) (SD(diff)) = 0.3 (2.8) W/kg(0.67), t = 0.75, p = 0.460). Data were homoscedastic (r = 0.05, p = 0.774) with LoA +/- 5.5 W/kg(0.67). CONCLUSIONS: The MSRT requires minimal equipment and training of assessors, and it is easy to perform. In the population studied, it provides scores that are repeatable, and anaerobic capacity (MPO) can be successfully predicted from its performance. It would seem therefore to be a useful field based test for use by female games players, their coaches, and support scientists.

Adult↗
PubMed2003

Catecholamine responses to high intensity cycle ergometer exercise: body mass or body composition?

The purpose of this study was to compare the sympathoadrenergic and metabolic responses following 30 s of maximal high intensity cycle ergometry exercise when cradle resistive forces were derived from total-body mass (TBM) or fat-free mass (FFM). Increases in peak power output (PPO) and pedal velocity were recorded when resistive forces reflected FFM (953 +/- 114 W vs 1020 +/- 134 W; 134 +/- 8 rpm vs 141 +/- 7 rpm ; P < 0.05). No differences were observed between mean power output (MPO), fatigue index (FI%), work done (WD) or heart rate (HR) when the TBM and FFM protocols were compared. There were no differences between the TBM and FFM protocols for adrenaline (A), noradrenaline (NA) or blood lactate concentrations ([La-]B) recorded at rest, immediately post or 24 h post exercise. However, increases in blood concentrations of A and NA (P < 0.05) were recorded for both the TBM and FFM protocol immediately post exercise. Significant correlations (P < 0.05) were recorded between PPOs, immediate post- exercise NA and [La-]B for both the TBM and FFM protocols. [La-]B levels were also significantly elevated (P < 0.01) immediately post exercise for both the TBM and FFM protocols. The results from this study suggest that greater peak power outputs are obtainable with no subsequent differences in neurophysiological or metabolic stress as determined by plasma A, NA and [La-]B concentrations when resistive forces reflect FFM and not TBM during loading procedures. The findings also indicate that immediate post exercise concentrations return to resting levels 24 h post exercise.

Adult↗
PubMed2002

High intensity exercise assessment: relationships between laboratory and field measures of performance.

The purpose of this study was to examine the relationship between high intensity cycle ergometry when resistive forces were optimised and field tests of high intensity performance in an elite sprint trained group (n = 12). Body mass, stature and age of the group were determined prior to testing (66.3 +/- 9.8kg, 177 +/- 7.6cm and 17 +/- 0.74 yrs respectively). Field tests of high intensity performance examined included sprinting. maximal shuttle running and jumping ability (vertical and horizontal). Significant correlations existed between all field tests (P < 0.01). Only moderate correlations were observed for values generated on the cycle ergometer and performance tests (P > 0.05). The results of the present study suggest that the optimised cycle ergometer test and the performance tests are unrelated when evaluated statistically. These findings also suggest that the sprinting and jumping tests examined are highly related and may be substituted for each other as possible predictors of high intensity ability.

Adolescent↗
PubMed2001

Replication-independent assembly of an insect virus (Tetraviridae) in plant cells.

Infectious virions of the insect RNA virus Helicoverpa armigera stunt virus (HaSV; Omegatetravirus, Tetraviridae) were assembled in cultured plant protoplasts of Nicotiana plumbaginifolia in the absence of detectable replication. Assembly of the virus, which has not been grown in cell culture, required cotransfection of a DNA plasmid expressing the HaSV capsid gene in combination with either genomic RNA or with DNA plasmids carrying the complete cDNAs to the two HaSV genomic RNAs. Each cDNA was placed under the control of the cauliflower mosaic virus 35S promoter and followed by a cis-acting ribozyme so that the resultant transcripts corresponded precisely to the two genomic RNAs. Protoplast assembly of infectious particles was confirmed by EM and bioassay of host insect larvae, which became diseased and produced virus particles confirmed as HaSV. Variant transcripts carrying nonviral sequences at either or both termini of the RNAs showed no infectivity, except for RNA2 carrying only a 3' terminal extension. No replication of HaSV in protoplasts was detected in pulse-labeling and blotting experiments. Insects showed less severe disease symptoms when fed protoplasts transfected with only the RNA1 and coat protein plasmids. The symptomatic larvae contained only RNA1 and failed to yield infectious progeny virus, suggesting that RNA1 is capable of self-replication. This novel plasmid-based system confirms that the reported sequence of HaSV represents an infective genome and establishes a procedure for the reverse genetics of a tetravirus.

Animals↗
PubMed2001

The relationship between total-body mass, fat-free mass and cycle ergometry power components during 20 seconds of maximal exercise.

The purpose of this study was to compare the maximal exercise performance of 10 men during friction braked cycle ergometry of 20 s duration when resistive forces reflected total body mass (TBM) or fat free mass (FFM). Fat mass was calculated from the sum of skinfold thicknesses. Increases (P < 0.05) in peak power output (PPO) were found between TBM and FFM (1,015+/-165 W TBM vs 1,099+/-172 W FFM). Decreases (P < 0.05) were observed for the time taken to reach PPO (3.8+/-1.4 s TBM vs 2.9+/-1 s FFM). Pedal velocity increased (P < 0.05) during the FFM protocol (129.4+/-8.2 rpm TBM vs 136.3+/-8 rpm FFM). Rating of perceived exertion (RPE) was also (P < 0.05) greater for FFM (18.4+/-1.6 TBM vs 19.8+/-0.4 FFM). No changes were found for Mean Power Output (MPO), fatigue index (FI) or Work Done (WD) between trials. These findings suggest that high intensity resistive force loading protocols may need to be reconsidered. Results from this study indicate that the active tissue component of body composition needs consideration in resistive force selection when ascertaining maximal cycle ergometer power profiles.

Adult↗
PubMed2000

Power output of legs during high intensity cycle ergometry: influence of hand grip.

Indices of mechanical power output were obtained from twelve subjects during high intensity leg cycle ergometry tests (20 second duration; 75 grams per kilogram total body mass) using two protocols: one with a standard handle-bar grip (with-grip), and one with supinated wrists (without-grip). Peak mechanical power, mean mechanical power, fatigue index and total mechanical work values were calculated for each subject during each test, and the sample mean differences associated with the two protocols were compared using paired Student t-tests. The with-grip protocol yielded significantly greater peak mechanical power output and greater fatigue index than the without-grip protocol (886 +/- 124W and 815 +/- 151W, respectively; and 35 +/- 10% and 25 +/- 8%, respectively; p<0.01). The electrical activity of the anterior forearm musculature was measured in the twelfth subject during the performance of each of the test protocols. While peak mechanical power output was greater during the with-grip protocol, than during the without-grip protocol, the electromyographs showed much greater forearm muscle activity during the with-grip protocol. Thus the protocol which allowed for the greatest measure of peak leg power output was also associated with considerable arm muscle activity. These findings should be considered when biochemical and physiological measurements are obtained from arm blood samples.

Adult↗
PubMed1993

Lungworm infection in a sheep flock in Maryland.

First-stage larvae of Protostrongylus rufescens were detected in the feces of a ram with diarrhea, anorexia, weight loss, and mucopurulent nasal discharge. Subsequently, a survey was initiated in the experimental sheep flocks maintained at the Agricultural Research Service's Helminthic Diseases Laboratory in Beltsville, Md to determine the extent and effect of infection with the parasite. Five of 31 ewes and 4 of 16 rams were found to be infected with the lungworm. Clinical signs of infection, which ranged from mild to severe, included diarrhea, weight loss, and respiratory distress. Natural transmission of the parasite to parasite-naive lambs grazing on pasture occurred during the course of this study. Three lambs born to infected ewes during this study were not infected, suggesting that there is no vertical transmission. Additionally, cattle grazing the same pastures as infected sheep were not infected with the parasite. Results of this study indicated that Protostrongylus rufescens can cause serious disease in domestic sheep in the United States and should be considered as a differential diagnosis in sheep with nonspecific respiratory tract signs.

Animals↗
PubMed1990

Preparation of triazolo[1,5-c]pyrimidines as potential antiasthma agents.

With the use of the human basophil histamine release assay, 5-aryl-2-amino[1,2,4]triazolo[1,5-c]pyrimidines were found to be active as mediator release inhibitors. These compounds were prepared by reacting arylamidines with sodium ethyl formylacetate or with ethyl propiolate to give pyrimidinones. Treatment with phosphorus oxychloride gave a chloropyrimidine, which was converted to a hydrazinopyrimidine with hydrazine. Cyclization, using cyanogen bromide, gave the triazolo[1,5-c]pyrimidines, after a Dimroth rearrangement. Following a structure-activity evaluation, the 5-[3-(trifluoromethyl)phenyl]-2-amino (8-10), 5-(3-bromophenyl)-2-amino (8-13), 5-[3-(difluoromethoxy)-phenyl]-2-amino (8-11), and 5-(4-pyridinyl)-2-amino (6-7) compounds were found to have the best activity. They were chosen for further pharmacological and toxicological study.

Animals↗
PubMed1989

Effects of lipoxygenase inhibitors in a model of lens-induced uveitis in dogs.

Uveitis was induced in dogs by intracameral injection of canine lens protein. The lipoxygenase inhibitors phenidone and norhydroguaiaretic acid, and dimethyl sulfoxide decreased fibrin production at 0.5 and 1 hour after induction of uveitis. Phenidone and norhydroguaiaretic acid also inhibited the initial increase in intraocular pressure early in the course of inflammation. Leukotriene B4 in the aqueous was measured by use of radioimmunoassay at 1 hour after inflammation. In control dogs, 230 to 1,700 pg of leukotriene B4/ml was measured; in dogs treated with phenidone, leukotriene B4 was not measured.

Animals↗
PubMed1986

Variations in bacitracin susceptibility observed in Staphylococcus and Micrococcus species.

Bacitracin susceptibility was evaluated as a laboratory method to differentiate staphylococci from micrococci. A total of 317 staphylococcal isolates and 108 micrococcal isolates were each tested for susceptibility to bacitracin by a disk-diffusion method using disks of three different potencies (0.04, 2.0, and 10.0 U) and a broth dilution method to obtain MICs. When a growth inhibition zone diameter breakpoint of greater than 10 mm was used to establish susceptibility with a 0.04-U disk, all micrococci were bacitracin susceptible and 94.6% of the staphylococci were resistant. Testing with disks of higher potency did not improve the specificity of the disk-diffusion method.

Bacitracin↗
PubMed1985

Evaluation of various rapid agglutination methods for the identification of Staphylococcus aureus.

A latex agglutination test (SeroSTAT Staph; Scott Laboratories, Fiskeville, R.I.) and two hemagglutination tests (Staphyloslide; BBL Microbiology Systems, Cockeysville, Md.; and Hemastaph; Remel, Lenexa, Kans.) were compared with the slide coagulase (SC) and tube coagulase (TC) tests at room temperature (22 to 25 degrees C) and at 37 degrees C for the rapid identification of Staphylococcus aureus. A total of 380 clinical strains of staphylococci were tested. The TC test performed at room temperature yielded the largest number of TC-positive results (n = 239), and based on this observation 239 organisms were classified as S. aureus and 141 were classified as non-S. aureus. The SC, TC (37 degrees C), SeroSTAT Staph, Staphyloslide, and Hemastaph tests correctly identified 210 (87.9%), 221 (92.5%), 238 (99.6%), 239 (100%), and 236 (98.7%) of the S. aureus isolates, respectively. Of the S. aureus isolates that were TC positive at room temperature 68% required 24 h of incubation before coagulase production was detected. There was one false-negative SeroSTAT Staph result and one false-negative Hemastaph result. The Staphyloslide test yielded two noninterpretable results (both organisms were later confirmed as non-S. aureus), whereas there were six noninterpretable results recorded with the Hemastaph test (four organisms were classified as non-S. aureus, and two were classified as S. aureus). The SeroSTAT Staph, Staphyloslide, and Hemastaph tests were all more sensitive than the conventional SC and TC (37 degrees C) tests and were considerably more rapid than the TC test at either temperature.

Coagulase↗
PubMed1985

Postpartum atony of the small and large intestine in a Holstein cow: a case of pseudo-obstruction.

A four-year-old Holstein, 23 days postpartum, was presented with abdominal distention. Gas filled viscera were detected in the right paralumbar fossa and pelvic canal. Surgery revealed cecal and colonic distention and generalized intestinal atony. There was no other evidence of gross pathology. The condition deteriorated during five post-operative days. Gross postmortem findings were not remarkable; histopathology revealed ganglionitis of the cranial mesenteric ganglion and myenteric plexus. A brief review of relevant literature for a differential diagnosis and an etiology is discussed.

Animals↗