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Biomedical subjects

L Martin

Publications and source records attributed to L Martin.

At least 127 records · Page 7Linked to original sources
PubMed2000

Inherited palmoplantar keratoderma and sensorineural deafness associated with A7445G point mutation in the mitochondrial genome.

We report a French pedigree with members having an inherited combination of non-epidermolytic palmoplantar keratoderma (NEPPK) and sensorineural deafness. The penetrance of both features was incomplete. Additional ectodermal defects were absent. The expression of numerous epidermal proteins (keratins, fillagrin, cornified envelope proteins, intercellular junction proteins including connexin 26, and loricrin) defined with immunolabelling was normal in the proband. The combination was shown to be associated with the A7445G point mutation in the mitochondrial genome (mtDNA). This mutation is responsible for a subtype of NEPPK which is so far the only mtDNA mutation-associated keratoderma.

Adolescent↗
PubMed2000

Comparison of critical swimming velocity and velocity at lactate threshold in elite triathletes.

The purpose of this study was to determine whether the critical swimming velocity (Vcrit) corresponds to the velocity at lactate threshold (V-LT) in elite triathletes. Eight elite triathletes (5 male, 3 female; age 26 +/- 4 years; height 1.7 +/- 0.1 m and body mass 75 +/- 4 kg) participated in the study. Vcrit, defined as the speed that could theoretically be maintained indefinitely without exhaustion, was expressed as the slope of a regression line between swimming distance covered and the corresponding times of five time trials over 100, 200, 400, 800 and 1500m and all combinations of these. Lactate threshold (LT) was determined by visual inspection as the point of first inflection of the lactate-work rate curve following 5 x 300 m swims of increasing velocity which were paced using the Aquapacer (Challenge and Response, Inverurie, Scotland). Velocities of the 300 m swims were -10, -5, 0, +5 and +10% of the average 100m pace from a 1500 m time trial. Vcrit was similar regardless of the combination or number of time trials used in the linear regression. For all subjects Vcrit was significantly faster (p <0.05) than V-LT (1.23 +/- 0.11 m x s(-1) and 1.15 +/- 0.10 m x s(-1) respectively). Blood lactate concentrations were also significantly higher (p < 0.05) at Vcrit (3.0 +/- 1.0 mM) than at LT (1.9 +/- 0.4 mM). Results from the present study demonstrate that Vcrit can be calculated from any two time trials in triathletes, however Vcrit did not represent V-LT in triathletes. Since Vcrit is faster than V-LT it is unlikely to be sustained indefinitely and consequently the notion of Vcrit should be re-evaluated in light of these findings.

Adult↗
PubMed2000

Reproducibility of diurnal variation in sub-maximal swimming.

Swimming training is characterised by the use of early morning and evening training sessions. The purpose of the present study was to investigate if the physiological and kinematic responses to swimming a typical training set are affected by time of day. Seven male collegiate swimmers (age 22 +/- 4 years; height 1.8 +/- 0.1 m; mass 82.1 +/- 4.1 kg) completed a standardised 600 m warm up followed by a 10 x 100 m sub-maximal freestyle set twice a day (06:30-08:00 h and 16:30-20:00 h) on three separate days. Swimming speed was controlled precisely throughout (limits of agreement multiplied/divided 1.00) using a new pacing device (Aquapacer, Challenge and Response, Inverurie, Scotland). Oral temperature (To), heart rate (HR), minute ventilation (VE), oxygen uptake (VO2), carbon dioxide expired (VCO2), respiratory exchange ratio (RER), capillary blood lactate (Bla), and glucose (BGL) were measured at rest and post exercise. Stroke rate (SR) and HR were measured during the first nine 100 m repetitions while rate of perceived exertion (RPE) was measured immediately after each 100 m. Significant diurnal variation was found at rest in To, HR, and VO2 on all three days and for VE and VCO2 on two of the days (P<0.05). During the training set no diurnal variation was evident in HR and SR responses or repetition times although RPE values were higher in morning trials compared to evening trials on two of the three days (P < 0.05). Post-exercise significant diurnal variation was found for To and blood glucose for two of the three days (P < 0.05). Therefore, although diurnal variation is evident at rest, there is no subsequent effect on physiological and kinematic responses during a sub-maximal training set following a standardised warm-up.

Adolescent↗
PubMed2000

Hospital safety climate and its relationship with safe work practices and workplace exposure incidents.

BACKGROUND: In the industrial setting, employee perceptions regarding their organization's commitment to safety (i.e., safety climate) have been shown to be important correlates to both the adoption and maintenance of safe work practices and to workplace injury rates. However, safety climate measures specific to the hospital setting have rarely been evaluated. This study was designed to develop a short and effective tool to measure hospital safety climate with respect to institutional commitment to bloodborne pathogen risk management programs and to assess the relationship between hospital safety climate and (1) employee compliance with safe work practices and (2) incidents of workplace exposure to blood and other body fluids. METHODS: A questionnaire, which included 46 safety climate items, was developed and tested on a sample of 789 hospital-based health care workers at risk for bloodborne pathogen exposure incidents. RESULTS: A 20-item hospital safety climate scale that measures hospitals' commitment to bloodborne pathogen risk management programs was extracted through factor analysis from the 46 safety climate items. This new hospital safety climate scale subfactored into 6 different organizational dimensions: (1) senior management support for safety programs, (2) absence of workplace barriers to safe work practices, (3) cleanliness and orderliness of the work site, (4) minimal conflict and good communication among staff members, (5) frequent safety-related feedback/training by supervisors, and (6) availability of personal protective equipment and engineering controls. Of these, senior management support for safety programs, absence of workplace barriers to safe work practices, and cleanliness/orderliness of the work site were significantly related to compliance (P<.05). In addition, both senior management support for safety programs and frequent safety-related feedback/training were significantly related to workplace exposure incidents (P<.05). Thus the most significant finding in terms of enhancing compliance and reducing exposure incidents was the importance of the perception that senior management was supportive of the bloodborne pathogen safety program. CONCLUSIONS: Hospital safety climate with regards to bloodborne pathogens can be measured by using a short, 20-question scale that measures 6 separate dimensions. Whereas all 6 dimensions are essential elements of overall safety climate, 3 dimensions are significantly correlated with compliance, and 1 dimension (senior management support) is especially significant with regard to both compliance and exposure incidents. This short safety climate scale can be a useful tool for evaluating hospital employees' perceptions regarding their organization's bloodborne pathogens management program. In addition, because this scale measures specific dimensions of the safety climate, it can be used to target problem areas and guide the development of intervention strategies to reduce occupational exposure incidents to blood and other body fluids.

Adult↗
PubMed2000

Psychological and physical health effects of sexual assaults and nonsexual traumas among male and female United States Army soldiers.

Lifetime trauma history was assessed in a health study of active duty United States Army soldiers. Five hundred fifty-five male and 573 female soldiers in the sample were asked whether they had ever experienced 14 different potentially traumatic experiences, including sexual assaults, violent stressors to self, and terrifying events that occurred to others and were secondarily traumatic through exposure by gaining information or as a witness to the event. Most soldiers had experienced multiple traumas, and premilitary exposure to events was much more common than exposure to events after entering the military. Global measures of current psychological distress and physical health symptoms were predicted by the lifetime number of sexual assaults and traumas to self. Social support from military unit leaders moderated the relationship between accumulated exposure to traumas and both health measures, whereas unit cohesion was directly associated with fewer mental health problems.

Adolescent↗
PubMed2000

Development and characterization of a bispecific single-chain antibody directed against T cells and ovarian carcinoma.

Bispecific antibodies with specificity for tumor antigen and CD3 have been shown to redirect the cytotoxicity of T cells against relevant tumor. Our objective was to generate single-chain bispecific antibodies (bsSCA) that could retarget mouse cytotoxic T lymphocytes (CTL) to destroy human ovarian carcinoma in a xenogeneic setting. A bsSCA, 2C11 x B43.13, was constructed by genetic engineering and expressed in mammalian cells. Molecular characteristics, binding properties, and ability to retarget CTL were studied. Western blot analysis showed that the product is a 65-kDa protein. Purification of antibodies could be done by single-step affinity chromatography using protein L-agarose with an unoptimized yield of 200 microg/L. BsSCA 2C11 x B43.13 was capable of binding to mouse CD3 and human CA125 as detected by FACS analysis of EL4 and OVCAR Nu3H2 cells, respectively. It could also bridge activated splenic T cells and human ovarian carcinoma as demonstrated by a bridge FACS assay. Redirected mouse CTL could mediate human target cell lysis in a 20-h 51Cr release assay despite that they are xenogeneic. Prolonged incubation of redirected CTL and tumor targets resulted in a dramatic reduction in tumor cell number. CD28 co-stimulation enhanced redirected CTL function in both types of assays. BsSCA 2C11 x B43.13 thus can be used as a preclinical immunotherapeutic model for human ovarian cancer in a xenogeneic setting.

Animals↗
PubMed2000

The beta-lactamases and beta-lactam antibiotic susceptibility of Yersinia enterocolitica.

One hundred and forty-five isolates of Yersinia enterocolitica of different serotypes and biotypes, including atypical biotypes, collected from various parts of the world, were examined for their susceptibility to beta-lactam antibiotics and expression of intracellular beta-lactamases. The reasons for the specificity of patterns of susceptibility to beta-lactams for each biotype or subtype of Y. enterocolitica were elucidated by examining their ss-lactamase activity. Whilst the biotypes and subtypes were uniformly susceptible to the newer beta-lactam antibiotics, the susceptibility pattern observed with other beta-lactams was specific to each biotype or subtype, because of the characteristics of beta-lactamase expression by strains within these groups. The susceptibility to these beta-lactam agents depended entirely on the extent of elaboration or the absence of one of the two beta-lactamases, enzyme A and enzyme B, found in the species. Detection of enzyme B by a disc diffusion test yielded inconsistent results, but detection of enzyme A by disc diffusion was highly reliable. This test clearly distinguished strains of biotype 2, serotype O:5,27 from those of biotype 2, serotype O:9 and biotype 3, serotypes O:1, 2a-3, O:3 and O:5.

Anti-Bacterial Agents↗
PubMed2000

Simple and inexpensive but highly discriminating method for computer-assisted DNA fingerprinting of Pseudomonas aeruginosa.

We describe here a method for computer-assisted fingerprinting of Pseudomonas aeruginosa. In this method, DNA is digested with SalI, and bands with molecular sizes of >/=9.7 kb are visually scored after electrophoresis on agarose gels. Pattern scores are entered into a Microsoft Excel database. In scoring, the number of bands within each of a set of molecular size ranges is scored, rather than the absolute molecular size of each band, substantially enhancing the speed and reproducibility of the method, while eliminating the need for using expensive gel scanning equipment and software. Pattern scores are used to generate matrices of genetic distance values, which can be visualized in neighbor-joining trees. The method reliably distinguishes two epidemiologically unrelated isolates in 99.3% of all comparisons. The genetic relationships between isolates observed with the method were consistent with those obtained by analysis of two P. aeruginosa genes, indicating that it provides valid estimates of genetic divergence between isolates. Using the method, respiratory tract isolates from cystic fibrosis patients in Green Lane Hospital in Auckland, New Zealand, were shown to be genetically less diverse than epidemiologically unrelated isolates from other patients. This finding was not due to the existence of clusters of related strains specialized toward colonization of the respiratory tract and thus was indicative of transmission between patients. Analysis of multiple isolates from individual cystic fibrosis patients suggested that up to five separate clusters of genetically related strains may simultaneously be present in a patient. The method described should significantly enhance our ability to investigate the epidemiology of P. aeruginosa.

Bacterial Outer Membrane Proteins↗
PubMed2000

Reflections of a novice researcher.

Nurses can benefit from active participation in research activities. Involvement in research is not just an academic pursuit but is essential for effective, quality care. Nurses should actively seek the support of colleagues and research support structures to enable involvement in research. Clinical nurses are capable of making an important research contribution.

Adaptation, Psychological↗
PubMed2000

ASE-1: an autoantigen in systemic lupus erythematosus.

ASE-1 is a 55 kDa nucleolar autoantigen. We show that autoantibodies to this antigen occur at a higher frequency in the sera of patients with SLE than in other systemic rheumatic diseases and that the specificity of ASE-1 as a serum marker of SLE increases as the number of epitopes recognized by the sera increases. Autoantibodies to ASE-1 were temporally associated with autoantibodies to HsEg5 but were not found in conjunction with other known serum markers of SLE. The frequency of antibodies to ASE-1 epitopes in a SLE cohort was approximately the same as anti-dsDNA. However, anti-dsDNA is associated with renal involvement, whereas ASE-1 reactivity shows an association with a history of serositis. We conclude that ASE-1 is correlated with serositis and that ASE-1 should be added to a list of autoantigens that are considered important serological features of SLE.

Adult↗
PubMed2000

Personal meanings of occupation for women in later life: two women compared.

Understanding the meaning of occupation for older women presents challenges to care providers because of the highly individual manner in which they enact those meanings. Two women interviewed in depth over a two-year period demonstrate the unique characteristics of activity patterns of older women, the meanings they ascribe to them, and the contribution of those activities to quality of life. The women were demographically similar, and described engaging in several common activity categories (connection to others, doing good, spiritual expression) that were particularly meaningful to them. The specific activities that they undertook were quite different. Findings suggest the importance of obtaining detailed information about older women in making plans for intervention to support desired activities in later life.

Aged↗
PubMed2000

Laser resection of a pedunculated tracheal adenoma.

We report a case of tracheal adenoma presenting as hemoptysis and reversible airflow obstruction in an ex-smoker. A questionable defect in the tracheal air shadow on a posteroanterior chest radiograph was shown on CT to be a pedunculated, mid-tracheal tumor. Two-stage bronchoscopic laser resection resulted in an apparently normal tracheal mucosa. Results of postresection spirometry were normal.

Adenoma↗
PubMed2000

Patterns of sediment dispersion coastwise the State of Bahia - Brazil.

Using the average directions of the main wave-fronts which approach the coast of Bahia State - coinciding with that of the main wind occurring in the area - and of their periods, we define a wave climate model based on the construction of refraction diagrams. The resulting model of sediment transport was able to reproduce, in a general way, the sediment dispersion patterns furnished by geomorphic indicators of the littoral drift. These dispersion patterns control the generation of different types of sediment accumulations and of coastal stretches under erosion. We demonstrate that the presence of the Abrolhos and Corumbaú Point coral reefs is an important factor controlling the sediment dispersion patterns, since them act as a large protection against the waves action.

Journal Article↗
PubMed2000

Engineering novel bioactive mini-proteins from small size natural and de novo designed scaffolds.

Mini-proteins, polypeptides containing less than 100 amino acids, such as (animal toxins, protease inhibitors, knottins, zinc fingers, etc.) represent successful structural solutions to the need to express a specific binding activity in different biological contexts. Artificial mini-proteins have also been designed de novo, representing simplified versions of natural folds and containing natural or artificial connectivities. Both systems have been used as structural scaffolds in the engineering of novel binding activities, according to three main approaches: i) incorporation of functional protein epitopes into structurally compatible regions of mini-protein scaffolds; ii) random mutagenesis and functional selection of particular structural regions of mini-protein scaffolds; iii) minimization of protein domains by the use of sequence randomization and functional selection, combined with structural information, in an iterative process. These newly engineered mini-proteins, with specific and high binding affinities within a small size and well-defined three-dimensional structure, represent novel tools in biology, biotechnology and medical sciences. In addition, some of them can also be directly used in therapy or present high potential to serve as drugs. In all cases, they represent precious structural intermediates useful to identify frameworks for peptidomimetic design or directly lead to new small organic structures, representing novel drug candidates. The engineering of novel functional mini-proteins has the potential to become a fundamental step towards the conversion of a protein functional epitope or a flexible peptide lead into a classical pharmaceutical.

Amino Acid Motifs↗
PubMed2000

Normal frequencies of the C677T genotypes on the methylenetetrahydrofolate reductase (MTHFR) gene among lymphoproliferative disorders but not in multiple myeloma.

The folate availability seems to be critical for the DNA integrity since it is required for the transfer of methyl groups in the biosynthesis of thymidilate. Although the excessive incorporation of uracils to the DNA can be efficiently removed, this mechanism of reparation produces many double-strand breaks from two opposing nicks. Several chromosomal abnormalities (mainly translocations and deletions perhaps not well understood) are involved in the origin of lymphoproliferative disorders. The TT homozygosity at nucleotide 677 in the gene of methylene tetrahydrofolatereductase (MTHFR), a key enzyme in folate metabolism, was recently linked to a significant protection against colon carcinoma and acute lymphoblastic leukaemia in adults. We analysed the genotype frequencies of C677T-MTHFR in a group of 143 patients with lymphoproliferative disorders (REAL classification) and 200 controls. Overally, the frequencies of the polymorphic allele were similar (35.3% and 32.0% respectively)(P=0.6). We did not find differences between patients and controls except for myeloma/plasmacytoma group (n=26) which showed a CC genotype less than expected (19% vs 46%) (p=0.01) with a frequency ratio of 0.28 (0.10-0.77). Even among the IgG myeloma cases only one patient showed a common genotype (CC) (1/15, 7%) (P=0.003). If these preliminary data are validated with prospective studies, the 677C allele of MTHFR gene could be confirmed as an effective multiple myeloma protective factor (specially for the IgG cases).

Adult↗
PubMed2000

Gender-related personal attributes and psychological adjustment among U.S. Army soldiers.

Personality characteristics associated with successful adaptation to military life are often described in gender-related terms. However, valid, reliable measures of gender-related personality characteristics have not been established for military populations. The purpose of this study was to validate an instrument for measuring gender-related personality characteristics in an active duty population. The Extended Personal Attributes Questionnaire was administered to 1,060 male soldiers and 305 female soldiers in U.S. Army support units. Results of a factor analysis indicated that there are three separate factors. The first denotes negatively valued aggressive traits (Negative Masculinity), the second denotes negatively valued passive traits (Negative Femininity), and the third combines positive instrumental and positive expressive traits, referred to as the Combined factor. Although positive instrumental traits (referred to as Masculinity) were related to fewer psychological symptoms, Negative Masculinity and Negative Femininity were associated with increased psychological symptoms. Positive expressive traits (referred to as Femininity) were unrelated to psychological symptoms.

Adaptation, Psychological↗