Neuromuscular response differences to power vs strength back squat exercise in elite athletes

The study's aim was to establish the neuromuscular responses in elite athletes during and following maximal 'explosive' regular back squat exercise at heavy, moderate, and light loads. Ten elite track and field athletes completed 10 sets of five maximal squat repetitions on three separate days. Knee extension maximal isometric voluntary contraction (MIVC), rate of force development (RFD) and evoked peak twitch force (Pt) assessments were made pre- and post-session. Surface electromyography [root mean square (RMS)] and mechanical measurements were recorded during repetitions. The heavy session resulted in the greatest repetition impulse in comparison to moderate and light sessions (P < 0.001), while the latter showed highest repetition power (P < 0.001). MIVC, RFD, and Pt were significantly reduced post-session (P < 0.01), with greatest reduction observed after the heavy, followed by the moderate and light sessions accordingly. Power significantly reduced during the heavy session only (P < 0.001), and greater increases in RMS occurred during heavy session (P < 0.001), followed by moderate, with no change during light session. In conclusion, this study has shown in elite athletes that the moderate load is optimal for providing a neuromuscular stimulus but with limited fatigue. This type of intervention could be potentially used in the development of both strength and power in elite athletic populations.

The second generation of the International Equine Gene Mapping Workshop half-sibling linkage map

A low-density, male-based linkage map was constructed as one of the objectives of the International Equine Gene Mapping Workshop. Here we report the second generation map based on testing 503 half-sibling offspring from 13 sire families for 344 informative markers using the CRIMAP program. The multipoint linkage analysis localized 310 markers (90%) with 257 markers being linearly ordered. The map included 34 linkage groups representing all 31 autosomes and spanning 2262 cM with an average interval between loci of 10.1 cM. This map is a milestone in that it is the first map with linkage groups assigned to each of the 31 automosomes and a single linkage group to all but three chromosomes.

The sequence of the human genome

A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.

Report of the International Equine Gene Mapping Workshop: male linkage map

The goal of the First International Equine Gene Mapping Workshop, held in 1995, was the construction of a low density, male linkage map for the horse. For this purpose, the International Horse Reference Family Panel (IHRFP) was established, consisting of 12 paternal half-sib families with 448 half-sib offspring provided by 10 laboratories. Blood samples were collected and DNA extracted in each laboratory and sent to the Lexington laboratory (KY, USA) for dispatch in aliquots to 14 typing laboratories. In total, 161 markers (144 microsatellites, seven blood groups and 10 proteins) were tested for all families for which the sire was heterozygous. Genealogies and typing data were sent for analysis to the INRA laboratory (Jouy-en-Josas, France) according to a specific format and entered into a database with input verification and output processes. Linkage analysis was performed with the CRIMAP program. Significant linkage was detected for 124 loci, of which 95 were unambiguously ordered using a multipoint analysis with an average spacing of 14.2 CM. These loci were distributed among 29 linkage groups. A more comprehensive analysis including synteny group data and FISH data suggested that 26 autosomes out of 31 are covered. The complete map spans 936 CM.

Genome duplications and other features in 12 Mb of DNA sequence from human chromosome 16p and 16q

Several publicly funded large-scale sequencing efforts have been initiated with the goal of completing the first reference human genome sequence by the year 2005. Here we present the results of analysis of 11.8 Mb of genomic sequence from chromosome 16. The apparent gene density varies throughout the region, but the number of genes predicted (84) suggests that this is a gene-poor region. This result may also suggest that the total number of human genes is likely to be at the lower end of published estimates. One of the most interesting aspects of this region of the genome is the presence of highly homologous, recently duplicated tracts of sequence distributed throughout the p-arm. Such duplications have implications for mapping and gene analysis as well as the predisposition to recurrent chromosomal structural rearrangements associated with genetic disease.

Accuracy of self-reported educational attainment among diverse patient populations: a preliminary investigation

Despite speculation concerning the accuracy of self-reported information, particularly from certain patient populations, many neuropsychologists continue to estimate premorbid intellectual functioning on the basis of self-reported educational attainment. This study examined 116 individuals with diverse diagnoses [i.e., alcoholism, posttraumatic stress disorder (PTSD), schizophrenia or schizoaffective, and dementia] to determine the accuracy of their self-reported high school educational attainment. Results suggest that at least half of all participants were inaccurate as defined by discrepancies between actual and estimated GPA greater than.5 on a traditional 4-point grading scale. Most patients were inaccurate in the direction of overestimating their educational attainment. Patients diagnosed with alcoholism and PTSD were significantly less accurate in recalling their educational history when compared to a group of normal-control subjects. Several subjects, whose records could not be verified, were found to have not attended high school as they had claimed. These results underscore the potential inaccuracy that exists when estimating premorbid intelligence using self-reported information.

A gene map of the human genome

The human genome is thought to harbor 50,000 to 100,000 genes, of which about half have been sampled to date in the form of expressed sequence tags. An international consortium was organized to develop and map gene-based sequence tagged site markers on a set of two radiation hybrid panels and a yeast artificial chromosome library. More than 16,000 human genes have been mapped relative to a framework map that contains about 1000 polymorphic genetic markers. The gene map unifies the existing genetic and physical maps with the nucleotide and protein sequence databases in a fashion that should speed the discovery of genes underlying inherited human disease. The integrated resource is available through a site on the World Wide Web at http://www.ncbi.nlm.nih.gov/SCIENCE96/.

Detection of bovine herpesvirus-1 in bovine semen by a nested PCR assay

A nested PCR assay targeting a portion of the glycoprotein IV gene has been developed for the detection of Bovine Herpesvirus-1 (BHV-1). Rapid and sensitive detection of the PCR products was achieved using a nonisotopic reverse dot-blot format with a visible color readout. Cross-reactivity of this PCR assay was not observed with the closely related BHV-3. The sensitivity of this assay when tested on a supernatant from a BHV-1 cell culture was approximately 4.5 TCID50 (50% tissue culture infectious dose). A procedure using the chelating resin Chelex 100 was used to prepare viral DNA from artificially inoculated samples of extended and raw semen for use in the PCR assay. In combination with nested PCR and reverse dot blot, this method allowed the detection of 5 x 10(3) TCID per 0.5 ml of semen, which is comparable to the detection in the Cornell Semen Test. The whole procedure can be completed in approximately 8 h. This assay has therefore the potential of replacing the currently available yet time consuming and costly detection methods for BHV-1 in bovine semen.

Molecular cloning and sequencing of an Australian isolate of proviral bovine leukaemia virus DNA: comparison with other isolates

The molecular cloning and characterization of an EcoRI fragment, 8.26 kb in size, of an Australian isolate of bovine leukaemia virus (pBLV-A1) is described. This fragment includes most of the proviral genome as well as 340 bp of flanking bovine DNA sequence at the 5' end. Approximately 790 bp, including the 3' long terminal repeat, was missing from this clone. At the level of restriction enzyme mapping, this isolate could be distinguished from American, Belgian and Japanese isolates. DNA sequencing of the entire clone demonstrated some variation at the amino acid level between pBLV-A1 and the Japanese and Belgian isolates, particularly in the gag gene. In that gene there were 59 amino acid changes compared to the Japanese isolate and 24 compared to the Belgian isolate. The greater number in the case of the Japanese isolate was due to both single nucleotide changes and frameshift in a single region of the gene. This study also demonstrates that there are large tracts of amino acid sequence, particularly within the env and pol genes, that are highly conserved in different isolates. Some of these conserved sequences exist in regions containing epitopes important in virus infectivity.

Lymphosarcoma development in sheep experimentally infected with bovine leukaemia virus

Twelve sheep were experimentally infected with a phytohemagglutinin (PHA) treated short term culture of lymphocytes from a cow naturally infected with BLV at the PL stage. Five of 12 (42%) BLV infected sheep had histologically confirmed lymphosarcoma 10-16 months after infection. The PBL's were increased to leukemic levels 3-21 weeks before death due to lymphoblastic leukemia. Lymphocyte proliferation and appearance of immature lymphocytes and lymphoblastic cells in the blood were a characteristic feature of tumour development following inoculation with an Australian strain of BLV. In contrast to a number of previous studies the peripheral lymph nodes of all infected sheep were clinically normal throughout the experimental period but at death gross tumours were evident in the mesentric lymph nodes and the heart in all cases. All the other lymph nodes, liver, spleen, kidney and lung were histologically infiltrated with lymphoid tumour cells. Gross tumours were present in the abomasum (1 out of 5) in the urinary tract (2 out of 5) and in the uterus (1 out of 2). The majority of the tumour cells isolated from the various tissues were centroblastic demonstrating that the malignant leukemia in experimentally infected sheep was of a multicentric centroblastic type. The central nervous system was not involved in any case.

Prediction of the duration of hospitalization in patients with respiratory syncytial virus infection: use of clinical parameters

To assess the possibility that clinical data available at the time of hospital admission for patients with respiratory syncytial virus infection could predict the length of hospitalization without antiviral therapy, the charts of all 102 patients admitted with laboratory documented respiratory syncytial virus infection during 1982 to 1985 were reviewed. Two thirds (65) of the patients remained hospitalized greater than three days. Prolonged hospitalization could have been predicted for 40 of the 65 patients (61.5%) based on the need for intubation and ventilation on admission (14 patients) or the presence of underlying cardiac or respiratory disease (28 patients). Of the infants hospitalized when they were less than 2 months of age, 40% required intubation and mechanical ventilation, although only 16% had underlying cardiac or respiratory disease. Mechanical ventilation was required at the time of admission or subsequently for 14% (5/36) of the 2- to 4-month-old infants with respiratory syncytial virus infection. Among the 56 patients without underlying cardiac or respiratory disease who did not require intubation at the time of admission, 25 (45%) remained hospitalized longer than three days (mean hospital stay for these 25 patients, regardless of age, was six days). Neither the respiratory rate nor the presence or absence of fever on admission was useful in predicting the likelihood of a longer hospital stay for the patients who did not require intubation. In addition, none of the initial laboratory data, including the WBC count, the percentage of band forms or polymorphonuclear leukocytes, the presence or absence of hypoxia, or the chest x-ray film findings could be correlated with a longer or shorter duration of hospitalization.(ABSTRACT TRUNCATED AT 250 WORDS)

Integration of bovine leukaemia virus in the ovine genome

Circulating lymphocytes and tumour cells from 12 sheep experimentally infected with bovine leukaemia virus (BLV), for periods of time varying from 9 to 48 weeks, were analysed for evidence of integrated and unintegrated provirus. Hybridization analysis demonstrated that the provirus was integrated at one or two sites in all cases. Integration was observed at different sites in the animals studied and there was no evidence of unintegrated virus molecules in infected sheep lymphocytes or tumour cells. The data obtained support a monoclonal origin of different tumours in the same sheep.

Lymphatic and blood vessels of the popliteal node in sheep

Our aim was to describe the lymphatic and blood vascular pathways to and from the popliteal lymph node in sheep. The blood vessels and lymphatics were filled with Microfil, and were cleared in methyl salicylate. Afferent lymphatics divide and anastomose as they pass dorsally along the lateral saphenous vein, and 6-12 lymphatics reach the node. Each branches extensively on the surface of the node giving rise to 20-50 terminal afferents which enter the node over a roughly circular area. Most enter the subcapsular sinus, but some penetrate deeply into the node. Lymph leaves the node through numerous initial efferent lymphatics, many of which contain valves. These join forming progressively larger vessels, and 2-4 efferent trunks emerge from the hilus. The hilus varies considerably in shape, depth and location, and it is filled with fat. Either a single artery, or up to 10-12 arteries derived from an anastomotic network or circle, enter the node from the hilar fat pad. Arteries may also enter at other sites. The arteries originate from the caudal femoral, or the medial circumflex femoral artery; a single node may receive blood from both arteries. This arrangement may help to maintain blood flow especially during an immune response, and despite external pressures applied to the arteries and node during movements of the animal.

Preregistration training of medical graduates in Queensland hospitals, 1977

This paper reports a survey of the 1976 graduates of The University of Queensland Medical School which was conducted as they completed their preregistration training. Study of the residents' perceptions of the adequacy of their training during the year revealed no significant difference between hospitals in terms of training in patient management. The nonmetropolitan hospitals were rated significantly higher than the metropolitan hospitals for training in procedures.