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Biomedical subjects

J Martin

Publications and source records attributed to J Martin.

At least 613 records · Page 34Linked to original sources
PubMed1992

Beneficial effects of the combined techniques of caudal and general anesthesia in the pediatric patient: two case reports.

The practice of combining a caudal anesthetic with a general anesthetic is frequently used in the management of pediatric patients. The principal advantage is improved postoperative pain management. Additionally, the perioperative reduction of inhalation agents as well as narcotic and non-narcotic analgesics provides a faster, more pleasant recovery from anesthesia that may result in a shorter hospital stay. The addition of caudally administered narcotics provides superior postoperative pain management in the pediatric patient requiring prolonged hospitalization. This article examines this combined technique in two pediatric patients: one, an ambulatory patient, the second, a patient requiring a postoperative intensive care admission.

Anesthesia, Caudal↗
PubMed1992

Sensitization to the storage mite Lepidoglyphus destructor in wheat flour respiratory allergy.

Occupational allergy due to hypersensitivity to cereal flours is relatively common among bakers and grain-store workers. Storage mites can contaminate wheat flour and could be an important cause of allergic symptoms due to inhalation. Forty-three patients with criteria for allergic sensitization to wheat flour (skin tests, specific IgE to wheat flour and positive challenge tests) were included in a study to investigate the prevalence of cosensitization to Lepidoglyphus destructor (Ld). This mite was the predominant species in the wheat flour samples supplied by our patients. We found that 30% of the patients had IgE-mediated hypersensitivity of Ld. Of these, 23% did not have a relationship with any bakery or agriculture. We conclude that the prevalence of sensitization to Ld in patients sensitized to wheat flour is important.

Adolescent↗
PubMed1992

Teamwork in the ophthalmic office.

The ophthalmic office staff consists of a team of professional, technical, and clerical personnel. Each employee needs commitment to achieving optimal care for each patient. Each staff member plays an important role contributing to total patient care.

Humans↗
PubMed1992

Cervical screening: default and compliance.

Health visitors could play a key role in educating at risk women about the benefits of cervical screening. Jane Martin and Peter J Main examine some of the models which outline barriers to screening uptake and consider which will help the health visitor to increase the knowledge and understanding of at risk clients.

Community Health Nursing↗
PubMed1991

Molecular isoforms of Na+/K(+)-ATPase in the nervous system and kidney of the spontaneously diabetic BB/Wor rat.

Na+/K(+)-ATPase was evaluated in the retina and kidney of the spontaneously diabetic BB/Wor rat after 1 and 4 months of insulin dependency. Retinal synthesis of the Na+/K(+)-ATPase was measured during a 2-h intravitreal pulse of [35S]methionine and analyzed by SDS-PAGE and scintillation counting. Synthesis of the alpha-1 and 'alpha(+)' (includes both alpha-2 and alpha-3) isoforms of the catalytic subunit was increased 123% and 69%, respectively at 4 months. Increases were also suggested at 1 month, but were not significant. The diabetes-dependent peak of synthesis in long-term diabetic rats turned over rapidly and by 3 days after intravitreal labeling, radioactively labeled enzyme was equal in both control and diabetic retinae. The amount of axonally transported, labeled enzyme recovered from endings of the optic nerve in the superior colliculus paralleled retinal labeling. Significant renal hypertrophy (48%) was noted at 4 months, but not at 1 month. The strophanthidin-inhibition constant for diabetes-induced renal enzyme was the same as for control enzyme (approx. 10(-4) M), indicating that diabetic renal hypertrophy does not induce a Na pump isozyme that is more sensitive to cardiotonic steroids. SDS-PAGE of the renal enzyme also failed to indicate more than one isoform of the alpha subunit.

Animals↗
PubMed1991

Role of an energized inner membrane in mitochondrial protein import. Delta psi drives the movement of presequences.

The transport of precursor proteins into mitochondria requires an energized inner membrane. We report here that the import of various precursor proteins showed a differential sensitivity to treatment of the mitochondria with the uncoupler carbonyl cyanide m-chlorophenylhydrazone. The differential inhibition by carbonyl cyanide m-chlorophenylhydrazone was not influenced by the length of the precursor, the presence of mature protein parts, or the folding state of the precursor but was specific for the presequence. Moreover, only the membrane potential delta psi and not the total proton motive force was required for the transport of precursors, indicating that protein translocation across the inner membrane is not driven by a movement of protons. We conclude that delta psi (negative inside) is needed for the translocation of the positively charged presequences, possibly via an electrophoretic effect.

Biological Transport↗
PubMed1991

Fluorimetric determination of oxidised and reduced glutathione in cells and tissues by high-performance liquid chromatography following derivatization with dansyl chloride.

A high-performance liquid chromatographic method utilising fluorimetric detection of oxidised and reduced glutathione, following derivatization with dansyl chloride is described. Dansyl derivatives are separated on an aminopropyl silica column with a methanol-sodium acetate gradient system giving detection limits (signal-to-noise ratio = 2) of 1 pmol. This is in the order of 100-fold more sensitive than established methods based on the ultraviolet detection of dinitrophenylglutathione derivatives. The present procedures have been used to determine oxidised and reduced glutathione in rat lung tissues and in alveolar macrophages.

Animals↗
PubMed1991

Chaperonin-mediated protein folding at the surface of groEL through a 'molten globule'-like intermediate.

Folding of two monomeric enzymes mediated by groE has been reconstituted in vitro. The groEL protein stabilizes the polypeptides in a conformation resembling the 'molten globule' state. Mg-ATP and groES then promote the acquisition of ordered tertiary structure at the surface of groEL. Folding requires the hydrolysis of about 100 ATP molecules per protein monomer. This active process of surface-mediated chain folding might represent a general mechanism for the formation of protein structure in vivo.

Adenosine Triphosphate↗
PubMed1991

Monocyte-derived neutrophil chemotactic factor/interleukin-8 is a potential mediator of crystal-induced inflammation.

The physical interaction of particulates with resident mononuclear phagocytes is a consistent feature in certain forms of crystal-induced inflammation. In this study, we observed that monosodium urate crystals stimulated the rapid release of neutrophil chemotactic activity from monocytes, and that this activity steadily increased over 24 hours. Because the release of monocyte-derived neutrophil chemotactic activity was markedly diminished by pretreatment of the monocytes with cycloheximide, and was completely removed from conditioned media by adsorption to heparin-agarose, we addressed the possibility that monocyte-derived neutrophil chemotactic factor/interleukin-8 (IL-8), a heparin-binding neutrophil-activating polypeptide, might modulate these activities. Urate crystal-induced IL-8 secretion from monocytes was verified by radioimmunoassay. In addition, an IL-8-specific antibody markedly inhibited the neutrophil-activating capacity of the conditioned media from monocytes activated by urate crystals, as well as by inflammatory silica crystals. Last, IL-8 was significantly increased in gouty synovial fluids (range 3.0-16.8 ng/ml, mean 8.4 ng/ml, n = 6) relative to osteoarthritic synovial fluids (range 1.1-1.7 ng/ml, mean 1.5 ng/ml, n = 6) (P = 0.006). We conclude that microcrystal-induced secretion of IL-8 by mononuclear phagocytes may mediate a number of forms of crystal-induced inflammation.

Arthritis, Gouty↗
PubMed1991

Distribution kinetics of netilmicin in human blister fluid: effect of renal impairment.

The pharmacokinetics of netilmicin in plasma and blister fluid were compared in 10 healthy volunteers with normal renal function and 10 voluntary patients with varying degrees of renal impairment. Netilmicin kinetics in plasma were characterized by an open two-compartment kinetic model. For the study of the kinetics of the antibiotic in blister fluid a specific kinetic distribution model was employed. In the healthy volunteers the plasma kinetics of netilmicin showed a behaviour similar to that of other aminoglycoside antibiotics, although a high blister/plasma partition coefficient was obtained, with a mean value of 4.27 +/- 1.65. The transfer of netilmicin in blister fluid governed by the constants K1b/Vb and Kbl had mean values of 0.19 +/- 0.09 h-1 l-1 and 0.25 +/- 0.10 h-1, respectively. In the patients with renal impairment plasma and blister fluid antibiotic levels showed a progressive accumulation. In these patients the affinity of netilmicin for blister fluid was significantly altered. The blister/plasma partition coefficient in this group of patients had a mean value of 2.65 +/- 1.33; the decrease being statistically significant (p = 0.023) with respect to the value obtained in the healthy volunteers. Similarly, the exit constant of netilmicin from blister fluid (Kb1) showed a statistically significant increase (p = 0.035) in the patients with renal impairment. The findings point to a loss of affinity of netilmicin for blister fluid as a result of renal impairment. Linear and logarithmic relationships were established between some pharmacokinetic parameters and creatinine clearance. Dosage schedules are proposed for netilmicin in patients with renal impairment.

Adult↗
PubMed1991

Mechanistic studies of two amino acid racemases of broad substrate specificity from Pseudomonas striata and Aeromonas caviae.

The conversion of L-[alpha-2H]alanine in H2O and unlabeled L-alanine in 2H2O into D-alanine, under nearly irreversible conditions, with the amino acid racemase from Pseudomonas striata showed significant internal transfer of the alpha-hydrogen. This result has been interpreted as being indicative of a single base mechanism for the racemization. The relative rates of deuterium incorporation into unlabeled D- and L-methionine by the two amino acid racemases of broad substrate specificity from P. striata and Aeromonas caviae, were measured in 2H2O. The results showed a markedly different pattern, dependent upon the configuration of the initial substrate; with D-methionine as substrate deuterium is incorporated into both enantiomers at approximately the same rate, but with L-methionine as substrate deuterium is incorporated considerably faster into the D than the L enantiomer. These results argue against a single base mechanism of racemization for these enzymes and are best rationalized in terms of a double base model where only one of the bases undergoes proton (deuterium) exchange with the solvent while the amino acid is enzyme-bound. The interpretation of the earlier experiment needs to be considered in light of these results.

Aeromonas↗
PubMed1991

Twitch potentiation during fatiguing exercise in the elderly: the effects of training.

Twitch potentiation was studied during a fatigue paradigm involving intermittent maximum voluntary contractions (MVCs) of the tibialis anterior muscle in the elderly and in young adults. Resting twitch torques were similar between groups, but twitch potentiation was significantly greater (241% vs 166%) in the young; the recovery of the twitch after fatigue was similar between groups. Contraction time, time to peak torque and half-relaxation time were all significantly slower in the elderly. Following 12 weeks of resistance training in the elderly, there was no significant change in the twitch contractile properties at rest, but there was a significant main effect of training on the degree of twitch potentiation during the same fatigue protocol (peak potentiation 192% post-training vs 165% pretraining). These data suggest that the mechanism(s) responsible for twitch potentiation following MVCs may be influenced by both aging and training.

Aged↗
PubMed1991

Sequence of a cellulase gene from the rumen anaerobe Ruminococcus flavefaciens 17.

A cellulase gene (endA) was isolated from a library of Ruminococcus flavefaciens strain 17 DNA fragments inserted in pUC13. The endA product showed activity against acid-swollen cellulose, carboxymethyl-cellulose, lichenan, cellopentaose and cellotetraose, but showed no activity against cellotriose or binding to avicel. Nucleotide sequencing indicated an encoded product of 455 amino acids which showed significant sequence similarity (ranging from 56% to 61%) with three endoglucanases from Ruminococcus albus, and with Clostridium thermocellum endoglucanase E. Little relatedness was found with a cellodextrinase previously isolated from R. flavefaciens FD1.

Amino Acid Sequence↗