PubMed Health⌕ Search

Biomedical subjects

J Martin

Publications and source records attributed to J Martin.

At least 433 records · Page 24Linked to original sources
PubMed1996

Inbreeding patterns in the Gredos Mountain Range (Spain).

The relationships among the frequency of consanguineous marriages, inbreeding coefficient, period, village size, and altitude are analyzed for three rural valleys belonging to the Sierra de Gredos (central Spain). These valleys occupy an area of about 30 x 80 km2, and the average total number of inhabitants for the period 1877-1970 was 58,621. Information about a sample of 23,744 weddings celebrated between 1875 and 1974 was obtained from 48 village parish registers. The mean inbreeding level up to second cousins for the whole area was 0.0012. A high percentage of inbreeding variation (83%) can be explained by each village's census size, resulting in a different interslope consanguinity pattern consisting of higher inbreeding levels in most northern localities in the Gredos mountains. This north-south geographic trend is consistent with results on blood polymorphisms from the same area (Mesa et al. 1994).

Altitude↗
PubMed1996

Effects of resistance training on bone mineral content and density in adolescent females.

Postmenarcheal adolescent girls performed resistance training (RT) for 26 weeks, which consisted of 4 sets of 13 exercises of varying and progressive intensity performed 3 times weekly on hydraulic resistance machines. Bone mineral was assessed by dual photon absorptiometry. Resistance training resulted in significant increases (pre-post) in biceps curl (21.4%), triceps press (21.5%), knee extension (25.1%), knee flexion (52.8%), and squat press (21.5%) strength. There were no significant differences between RT and control (C) groups initially, and no significant effects of training (pre-post) for total body (TB) or lumbar spine (LS) bone mineral content (BMC) or bone mineral density (BMD). The largest increases in LS bone mineral occurred during the first 13 weeks, and although not significant, the increases in LS BMC (g) (3.9 vs. 5.9%), LS BMC (g.cm-1) (2.6 vs. 5.9%), LS areal BMD (g.cm-2) (1.48 vs. 4.75%), and LS bone mineral apparent density (BMAD, g.cm-3) (0.47 vs. 4.13%) were greater in the RT compared with the C group during this period. In conclusion, resistance training resulted in a trend towards a transient increase in LS bone mineral during the first 13 weeks, but despite significant strength gains, there were no significant changes in TB or LS bone mineral after 26 weeks of training.

Adolescent↗
PubMed1996

Ethics and health services: the debate continues.

As technological options continue to proliferate, so do questions about choice of treatment. The author reviews some of the values and priorities on which decisions can be based. Since these are matters that affect societies as a whole, they must be fully and openly discussed, with the active participation of all concerned, including the public for whom the health services exist.

Community Participation↗
PubMed1995

[Hand and arm vibration syndrome caused by mechanical screw driver].

Authors performed angiological, neurological and radiological examination of 17 persons working with power screw-drivers. Vibration measurement of the tools was made too. 10 patients had symptoms and signs corresponding to the hand-arm vibration syndrome. The vibration of some tools exceeded the maximal allowable acceleration level according to ISO 5349. On the ground of the results authors conclude that some power screw-drivers can cause hand-arm vibration syndrome. The importance of choosing of the right tools and the significance of the periodical examinations are underlined in the prevention of the damages.

Adult↗
PubMed1995

Asymmetrical interaction of GroEL and GroES in the ATPase cycle of assisted protein folding.

The chaperonins GroEL and GroES of Escherichia coli facilitate protein folding in an adenosine triphosphate (ATP)-dependent reaction cycle. The kinetic parameters for the formation and dissociation of GroEL-GroES complexes were analyzed by surface plasmon resonance. Association of GroES and subsequent ATP hydrolysis in the interacting GroEL toroid resulted in the formation of a stable GroEL:ADP:GroES complex. The complex dissociated as a result of ATP hydrolysis in the opposite GroEL toroid, without formation of a symmetrical GroEL:(GroES)2 intermediate. Dissociation was accelerated by the addition of unfolded polypeptide. Thus, the functional chaperonin unit is an asymmetrical GroEL:GroES complex, and substrate protein plays an active role in modulating the chaperonin reaction cycle.

Adenosine Diphosphate↗
PubMed1995

[Vibration-induced Raynaud phenomenon caused by an electric hedge trimmer].

Authors observed Raynaud's phenomenon verified by cold-provocation test and measuring finger systolic blood pressure on a man working with bush cutter equipment installed on a tractor. Vibration measurements showed acceleration superior to maximal allowable level. Other causes of a secondary Raynaud's phenomenon were excluded by means of detailed internal examination. On the ground of the exposure data and lack of other ethiological factors the authors think that the patient had vibration-induced Raynaud's phenomenon. For prevention they proposed the diminishing of the daily exposure time and periodical medical examinations. They want to draw the attention for this sort of exposure.

Adult↗
PubMed1995

Detection and quantitation of hexa-histidine-tagged recombinant proteins on western blots and by a surface plasmon resonance biosensor technique.

The use of short peptide affinity tag sequences has become commonplace for the expression and purification of recombinant proteins. Many of these tags are antibody epitopes and detection of tagged proteins via Western blots is straightforward. However, the most common affinity tag used at present for the expression of recombinant proteins is a hexa-histidine, or like sequence, which exhibits strong affinity for Ni(II). The one drawback of histidine-containing affinity tags is the inability to specifically detect such recombinant proteins on Western blots. Here we describe the synthesis and use of biotinyl-nitrilotriacetic acid which, in combination with streptavidin-horseradish peroxidase, allows for the detection of hexa-histidine-tagged recombinant proteins on Western blots. In addition, we describe a surface plasmon resonance technique, employing a solid-phase Ni(II)-nitrilotriacetic acid complex, for the detection and quantitation of hexa-histidine-tagged recombinant proteins in solution. The surface plasmon resonance technique also allows for the oriented immobilization of the recombinant proteins for subsequent ligand interaction studies.

Affinity Labels↗
PubMed1995

Current trends in molecular recognition and bioseparation.

Molecular recognition guides the selective interaction of macromolecules with each other in essentially all biological processes. Perhaps the most impactful use of biomolecular recognition in separation science has been in affinity chromatography. The results of the last 26 years, since Cuatrecases, Wilchek and Anfinsen first reported the purification of staphylococcal nuclease, have validated the power of biomolecular specificity for purification. This power has stimulated an explosion of solid-phase ligand designs and affinity chromatographic applications. An ongoing case in point is the purification of recombinant proteins, which has been aided by engineering the proteins to contain Affinity-Tag sequences, such as hexa-histidine for metal-chelate separation and epitope sequence for separation by an immobilized monoclonal antibody. Tag technology can be adapted for plate assays and other solid-phase techniques. The advance of affinity chromatography also has stimulated immobilized ligand-based methods to characterize macromolecular recognition, including both chromatographic and optical biosensor methods. And, new methods such as phage display and other diversity library approaches continue to emerge to identify new recognition molecules of potential use as affinity ligands. Overall, it is tantalizing to envision a continued evolution of new affinity technologies which use the selectivity built into biomolecular recognition as a vehicle for purification, analysis, screening and other applications in separation sciences.

Chromatography, Affinity↗
PubMed1995

Requirement for peptide in alloreactive CD4+ T cell recognition of class II MHC molecules.

To examine the role of peptide in alloreactive class II MHC-restricted responses, we transfected I-A molecules into the Ag-processing defective mutant cell line, T2. Consistent with their defective Ag-processing phenotype, the T2 transfectants predominantly express SDS-unstable I-A molecules on their surface. These cells and phenotypically normal APCs were used to study primary and secondary alloreactive T cell responses in limiting dilution assays. The results demonstrate that the majority of CD4 T cells that participate in primary alloresponses and essentially all the CD4 T cells that participate in secondary alloresponses recognize I-A conformers that depend on the presence of peptide and do not recognize the SDS-unstable I-A expressed by T2 transfectants. To further investigate the requirement for peptide in these responses, we incubated the T2 transfectants with E alpha 52-68 peptide and generated SDS-stable I-A-peptide complexes on the cell surface. The I-Ab-E alpha peptide complexes expressed on T2 cells are stimulatory in secondary alloresponses if the T cells were exposed to the same I-A peptide complex during the priming step. These studies demonstrate that peptide-containing class II MHC is the relevant ligand for alloreactive T cells, and identify an alloreactive response to a peptide (E alpha 52-68) derived from a highly expressed cell surface "self" Ag, the I-E molecule.

Animals↗
PubMed1995

Serum sickness like illness and antimicrobials in children.

AIM: To determine which antimicrobials are associated with the development of serum sickness like reactions in children admitted to hospital in Christchurch. METHOD: A retrospective case note review of children admitted with serum sickness like reactions over a 10 year period was carried out. 59 children were identified and 30 of these were eligible for inclusion in the study. RESULTS: Of the 30 children with serum sickness like reaction, 19 had received cefaclor alone, six penicillin V, two amoxycillin, and one each flucloxacillin cotrimoxazole and triacetylolendomycin (TAO). Children received these antimicrobials for 3-10 days. CONCLUSION: In this study cefaclor was commonest antimicrobial agent associated with the development of serum sickness like reaction. This association should receive consideration prior to prescribing cefaclor to children.

Amoxicillin↗
PubMed1995

Isolation of genes encoding beta-D-xylanase, beta-D-xylosidase and alpha-L-arabinofuranosidase activities from the rumen bacterium Prevotella ruminicola B1(4).

Prevotella ruminicola B1(4) is a strictly anaerobic, Gram-negative, polysaccharide-degrading rumen bacterium. Xylanase activity in this strain was found to be inducible, the specific activity of cells grown on xylan being increased at least 20-fold by comparison with cells grown on glucose. Ten bacteriophage clones expressing xylanase activity were isolated from a lambda EMBL3 genomic DNA library of P. ruminicola B1(4). These clones were shown to represent four distinct chromosomal regions, based on restriction enzyme analysis and DNA hybridisation. Three groups of clones encoded activity against oat spelt xylan but not carboxymethylcellulose (CMC). In one of these groups, represented by clone 5, activities against pNP-arabinofuranoside and pNP-xyloside were found to be encoded separately from endoxylanase activity. The fourth region encoded activity against CM cellulose and lichen, in addition to xylan, and contains an endoglucanase/xylanase gene isolated previously.

Animals↗