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Biomedical subjects

M Lynch

Publications and source records attributed to M Lynch.

At least 163 records · Page 9Linked to original sources
PubMed1994

Preparing children for day surgery.

This study measured the effect of a group preoperative teaching program on the level of children's emotional distress during day surgery. The sample consisted of 30 children, ages 3 through 10, scheduled for elective surgery. One group attended a structured program and received procedural and sensory information within 2 weeks of their surgery. The other group did not receive this intervention. A t test identified significant differences between the groups. Children who attended the preoperative teaching program demonstrated less emotional distress than children who did not receive this intervention. These findings reinforce the positive outcomes of preoperative teaching programs that provide procedural and sensory information to children as preparation for day surgery.

Ambulatory Surgical Procedures↗
PubMed1994

Expression of keratins in mouse vaginal epithelium.

In the epithelium of the rodent vagina proliferation and differentiation are tightly regulated by ovarian hormones. Estrogens stimulate proliferation and squamous differentiation, whereas progesterone redirects differentiation to a mucus-secreting epithelium formed by goblet-like cells. In the present study, we used monospecific keratin antibodies to show the expression and distribution of keratins in SENCAR mouse vaginal epithelium in different stages of the estral cycle and in ovariectomized animals. In ovariectomized animals, the vaginal epithelium expressed K6, K8, K13 and K14, but not K1. After estrogen treatment, K1 was expressed. During proestrus and estrus, the keratin pattern was essentially identical to that observed in 17 beta-estradiol-stimulated animals. In contrast, during the progestational stages (metaestrus and diestrus) or after progesterone treatment of ovariectomized mice, the most relevant change was the loss of K1. Together, these results show that K1 expression is induced by estrogens in the vaginal epithelium. In contrast, K6, K8, K13 and K14 are constitutively expressed even when squamous differentiation is not observed.

Animals↗
PubMed1993

Vitamin K1 metabolism and the production of des-carboxy prothrombin and protein C in the term and premature neonate.

This study investigated the incidences of undercarboxylated (protein induced by vitamin K absence: PIVKA) prothrombin and protein C in 496 neonates across a wide range of gestational ages. These findings are related to vitamin K1 levels (an indicator of cofactor availability) and vitamin K1 epoxide levels (a measure of the efficiency of the hepatic vitamin K cycle). PIVKA protein C was present in at least trace amounts in 27% of infants; whereas, PIVKA prothrombin was present in 7% of infants. PIVKA prothrombin and protein C were present at high plasma concentrations in 2% to 3% of term and preterm neonates and both PIVKA protein C and prothrombin increased with gestational age. Despite elevated plasma concentrations of PIVKA protein C and diminished levels of normally carboxylated protein C, clinical thrombosis was not observed. The mean (+/- SD) vitamin K1 level in the study population was 0.009 +/- 0.02 nmol/L (adult reference interval: 0.3 to 2.6 nmol/L) with no clear relationship between vitamin K1 levels and production of PIVKA protein C or prothrombin. By comparison with adults, the epoxide form of the vitamin comprised an abnormally high proportion of total vitamin K1; this suggests possible inefficiencies in hepatic reductase cycling.

Biomarkers↗
PubMed1993

The relationship between affinity of progestins and antiprogestins for the progesterone receptor in breast cancer cells (ZR-PR-LT) and ability to down-regulate the receptor: evidence for heterospecific receptor modulation via the glucocorticoid receptor.

In a human breast cancer cell line (ZR-PR-LT) we have found a poor overall correlation between affinity of progestins and anti-progestins for the progesterone receptor (PGR), concentration required for receptor down-regulation and anti-proliferative potency. Medroxyprogesterone acetate (MPA) and the anti-progestin RU 38.486, which possess glucocorticoid and antiglucocorticoid activity, respectively, cause receptor down-regulation at lower concentrations than their Kdi for [3H] ORG 2058 binding sites. In addition dexamethasone markedly down-regulates PGR at concentrations which fail to interact with PGR suggesting that heterospecific modulation of PGR occurs via the glucocorticoid receptor. In contrast the progestin ORG2058 and the anti-progestin ZK 98.299 caused 50% PGR down-regulation at a concentration (EC50) 50-fold higher than their Kdi values. ZK 112.993 was 500-fold more potent at PGR down-regulation than ZK 98.299 but had only a 5-fold higher affinity for PGR. Anti-proliferative concentrations of progestins/anti-progestins showing were generally higher than either Kdi values or EC50 values.

Binding, Competitive↗
PubMed1993

Self-image resilience and dissonance: the role of affirmational resources.

It was predicted that high self-esteem Ss (HSEs) would rationalize an esteem-threatening decision less than low self-esteem Ss (LSEs), because HSEs presumably had more favorable self-concepts with which to affirm, and thus repair, their overall sense of self-integrity. This prediction was supported in 2 experiments within the "free-choice" dissonance paradigm--one that manipulated self-esteem through personality feedback and the other that varied it through selection of HSEs and LSEs, but only when Ss were made to focus on their self-concepts. A 3rd experiment countered an alternative explanation of the results in terms of mood effects that may have accompanied the experimental manipulations. The results were discussed in terms of the following: (a) their support for a resources theory of individual differences in resilience to self-image threats--an extension of self-affirmation theory, (b) their implications for self-esteem functioning, and (c) their implications for the continuing debate over self-enhancement versus self-consistency motivation.

Adaptation, Psychological↗
PubMed1993

Toward an ecological/transactional model of community violence and child maltreatment: consequences for children's development.

In recent decades it has become increasingly apparent that violence affects a significant proportion of families in the United States (Bureau of Justice Statistics 1983). Violence, in fact, is becoming a defining characteristic of American society. A recent comparison of the rates of homicide among 21 developed nations indicates that the United States has the highest homicide rate in the world, and its rate is more than four times higher than the next highest rate (Fingerhut and Kleinman 1990). What is even more alarming is the high incidence of violent death and injury for children and adolescents in the United States. Acts of violence are the cause of death for over 2000 children between the ages of 0 and 19 years each year, and more than 1.5 million children and adolescents are abused by their adult caretakers each year (Christoffel 1990).

Child↗
PubMed1993

Comparison of alfentanil with suxamethonium in facilitating nasotracheal intubation in day-case anaesthesia.

We have performed a prospective study in 100 adults (ASA I or II) undergoing day-case dental extraction to compare the conditions for intubation and the postoperative sequelae of suxamethonium and alfentanil as adjuncts to propofol. The patients were allocated randomly to two groups comparable in age, sex and weight. Successful intubation was achieved in 100% of the suxamethonium group and 90% of the alfentanil group. Of the patients who received suxamethonium, 74% developed myalgia on the day after surgery, compared with 20% in the alfentanil group (P < 0.001). The proportion of patients who developed sore throat was also less in the alfentanil group than in the suxamethonium group (P < 0.05). The proportion of patients who complained of nausea in the two groups was not significantly different. We conclude that alfentanil, as an adjunct to propofol to facilitate tracheal intubation, is more acceptable to patients than suxamethonium in anaesthesia for day-case surgery.

Adolescent↗
PubMed1993

Vaginitis due to Saccharomyces cerevisiae: epidemiology, clinical aspects, and therapy.

Vaginitis due to Saccharomyces species is extremely rare. Nine patients with 20 vaginal isolates of Saccharomyces cerevisiae who presented with either asymptomatic vaginal colonization or symptomatic vaginitis indistinguishable from that caused by Candida albicans are described. All patients had a history of chronic or recurrent vaginitis, and all but two had systemic or local predisposing factors. In vitro tests of antimycotic sensitivity revealed reduced susceptibility of S. cerevisiae to the majority of available azole agents, with outright resistance to fluconazole. In accordance with these findings, the clinical response to conventional topical and oral antimycotic drugs was frequently suboptimal and incomplete. Electrophoretic karyotyping of strains revealed several distinct types of S. cerevisiae; this information permitted both longitudinal follow-up and differentiation of relapse from reinfection. In three patients with recurrent vaginitis, a unique epidemiological relationship was documented between S. cerevisiae and Torulopsis glabrata, another unusual and resistant vaginal pathogen. Isolation of S. cerevisiae from the vagina of symptomatic patients should not be ignored; treatment of vaginal infection with this yeast requires selected, often prolonged therapy.

Adult↗
PubMed1993

A method for calibrating molecular clocks and its application to animal mitochondrial DNA.

A generalized least-squares procedure is introduced for the calibration of molecular clocks and applied to the complete mitochondrial DNA sequences of 13 animal species. The proposed technique accounts for both nonindependence and heteroscedasticity of molecular-distance data, problems that have not been taken into to account in such analyses in the past. When sequence-identity data are transformed to account for multiple substitutions/site, the molecular divergence scales linearly with time, but with substantially more variation in the substitution rate than expected under a Poisson model. Significant levels of divergence are predicted at zero divergence time for most loci, suggesting high levels of site-specific heterozygosity among mtDNA molecules establishing in sister taxa. For nearly all loci, the baseline heterozygosity is lower and the substitution rate is higher in mammals relative to other animals. There is considerable variation in the evolutionary rate among loci but no compelling evidence that the average rate of mtDNA evolution is elevated with respect to that of nuclear DNA. Using the observed patterns of interspecific divergence, empirical estimates are derived for the mean coalescence times of organelles colonizing sister taxa.

Animals↗
PubMed1993

Medical services in social health maintenance organizations.

An evaluation of medical services for elderly members in the Social Health Maintenance Organization (SHMO) demonstrations is presented. The SHMOs generally failed to offer special geriatric medical services to the frail elderly, and the coordination of SHMO medical services with the special long-term care and case management services offered by the SHMOs was limited. These limitations led to some problems for the elderly in terms of access, continuity of care, and satisfaction. Variations in medical services occurred across sites, but generally the SHMOs established by mature HMO organizations appeared to offer more efficient and effective medical services than newly formed SHMOs.

Aged↗
PubMed1993

Nasal epithelial ion transport and genetic analysis of infertile men with congenital bilateral absence of the vas deferens.

It has been suggested that congenital bilateral absence of the vas deferens (CBAVD), an important cause of male infertility, is a variant of cystic fibrosis (CF). This study describes a defect in chloride conductance across the nasal epithelium of subjects with CBAVD which is dissimilar to that found in patients with CF. It also demonstrates normal sodium transport across the nasal epithelium in these men, in contrast to patients with CF who exhibit increased sodium absorption. The increased frequency of CFTR mutations in these men implicates the CFTR gene in the pathogenesis of this disorder. Genetic analysis of men with CBAVD who were heterozygous for a known CFTR mutation failed to identify a second mutation within any of the exons or introns of the CFTR gene. These results demonstrate that most men presenting with CBAVD are not compound heterozygotes for mutations within the CFTR gene and can be distinguished from individuals with atypical or asymptomatic CF on the basis of the bioelectric properties of their nasal epithelium. We postulate that mutations in the promoter region or at other regulatory sites of the CFTR gene may be responsible for the CBAVD phenotype in a proportion of cases.

Biological Transport↗
PubMed1993

Why do patients develop reactions to streptokinase?

Minor reactions to streptokinase are not uncommon, although the etiology is unknown. It is widely presumed, however, that these, like the more serious immune reactions, are antibody-mediated. We measured specific anti-streptokinase IgG, subclasses IgG1, IgG2, IgG3, IgG4 and IgE by ELISAs, haemagglutination, indirect Coombs' test and immunoblotting in six patients who developed reactions to streptokinase. Evidence of complement activation by streptokinase was sought by a haemolytic complement assay and by measurement of C3, C4 and C3d. The patients who reacted to streptokinase presented with low titres of anti-streptokinase IgG (median = 5; range 0-32) and IgG1 (median = 3; range 0-14). No evidence of any other IgG subclass was found, nor of specific anti-streptokinase IgE. Anti-streptokinase IgG1 was found to fix complement; patients who reacted to streptokinase were found to have low levels of total complement 1 year post reaction. Probable aggregates and fragments of human albumin (added stabilizer) were found in the streptokinase preparation and proved to be antigenic in some patients, but were not found to be related to the development of reactions. The findings suggest that patients who develop reactions to streptokinase cannot be predicted on the basis of antibody titres at presentation. Minor reactions to streptokinase would not appear to be antibody-mediated, although complement activation may be involved.

Aged↗
PubMed1993

Relaxation of vascular smooth muscle induced by low-power laser radiation.

The relaxation of rabbit aorta rings induced by low-power laser radiation was investigated in vitro to determine the location of the chromophore(s) responsible for this response and evaluate possible mechanisms. An action spectrum for relaxation was measured on rabbit thoracic aorta rings precontracted with norepinephrine. The decrease in isometric tension was measured during exposure to laser light (351-625 nm) delivered via a fiber optic to a small spot on the adventitial surface. The shortest UV wavelength (351 nm) was 35-fold more effective than 390 nm and 1700-fold more effective than 460 nm. Ultraviolet wavelengths also produced greater maximum relaxation (0.40-0.45) than visible wavelengths (0.20-0.25), suggesting that photovasorelaxation involves more than one chromophore. The adventitial layer was not necessary for photovasorelaxation, indicating that the light is absorbed by a chromophore in the medial layer. The same degree of relaxation was obtained on rings without adventitia when either one-half of the ring, or a small spot was irradiated indicating that communication between smooth muscle cells spreads a signal from the area illuminated to the entire ring. The mechanism for photovasorelaxation was investigated using potential inhibitors. N-monomethyl-L-arginine and N-amino-L-arginine, inhibitors of nitric oxide synthase, did not alter photovasorelaxation nor did indomethacin, an inhibitor of cyclooxygenase, and zinc protoporphyrin, an inhibitor of heme oxygenase.

Animals↗
PubMed1993

Nonocular Chlamydia infection and risk of ocular reinfection after mass treatment in a trachoma hyperendemic area.

PURPOSE: The presence of nasal discharge on a child's face increases the risk of active trachoma, suggesting that Chlamydia trachomatis in nasal secretions may be a possible source of ocular reinfection. The prevalence of chlamydia in nasal secretions and the risk of reinfection after mass treatment was investigated in a hyperendemic area of Tanzania. METHODS: In one village a total of 232 children aged 1 to 7 years were followed before and after mass treatment. Clinical trachoma, and microbiologic evidence of chlamydia, were assessed at baseline, 2 and 4 weeks into mass treatment, and 4 weeks after treatment stopped. The presence of chlamydia in ocular and nasal secretions was determined by polymerase chain reaction-enzyme immunoassay techniques. RESULTS: Of the 232 children, 59% had clinical trachoma and 27% had nasal specimens positive for chlamydia. Children with positive ocular chlamydia specimens and/or clinical trachoma were significantly more likely to have positive nasal specimens. At the end of mass treatment, only 4% of children had positive ocular specimens. However, 1 month after treatment stopped, the incidence of new infection was 21%. The rate of new ocular infections in those who had negative ocular specimens after treatment was similar between those who had positive and those who had negative nasal specimens at baseline. Positive ocular specimens at baseline was not a predictor of risk of new infection after treatment (odds ratio = 1.18, 95% confidence interval = 0.58, 2.40), suggesting these new infections were not the result of latent or persistent organism. CONCLUSIONS: These data do not support a role for nasal secretions in causing reinfection after treatment. One mass topical treatment alone is unlikely to be effective in trachoma hyperendemic areas as shown by the rapid re-emergence of infection.

Base Sequence↗