Search PubMed⌕ Search

Biomedical subjects

M L Martin

Publications and source records attributed to M L Martin.

At least 55 records · Page 3Linked to original sources
PubMed1996

Denaturing gradient gel electrophoresis to diagnose multiple endocrine neoplasia type 2.

Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant cancer syndrome caused by mutations in the RET protooncogene. Others have already demonstrated the value of genetic testing in known MEN 2 kindreds. Previously described approaches to DNA-level diagnosis, particularly of index cases, are tedious. We developed appropriate denaturing gradient gel electrophoresis (DGGE) conditions for analysis of exons 10, 11, and 16 of this gene, where many of the pathogenic mutations map. We screened 16 members of a three-generation MEN 2 kindred by DGGE and found five affected but still asymptomatic patients, ranging in age from 5 to 67 years. We used DGGE to localize the pathogenic mutations and screen at-risk individuals in several other kindreds. DGGE--which requires no radioactive, fluorescent, or chemiluminescent labeling--is ideally suited to the diagnosis of MEN 2 because of the syndrome's dominant genetics and the rarity of clinically silent variants in the RET gene.

Adolescent↗
PubMed1995

Site-specific isotope fractionation in the characterization of biochemical mechanisms. The glycolytic pathway.

For a given biochemical transformation, such as the fermentation reaction, the redistribution coefficients, which relate the natural site-specific isotope contents in end products to those of their precursors, are a source of mechanistic information. These coefficients characterize the traceability of specific hydrogens in the products (ethanol and water) to their parent hydrogens in the starting materials (glucose and water). In conditions of complete transformation, they also enable intermolecular exchanges with the water medium to be estimated. Thus it is directly confirmed that hydrogens 1, 2, 6, and 6' of glucose are strongly connected to the methyl site I of ethanol obtained by fermentation by Saccharomyces cerevisiae. However, whereas hydrogens 6 and 6' are transferred to a great extent, transfer is only partial for hydrogen 2, and it is even less for hydrogen 1. Because the two moieties of glucose corresponding to carbons 1-2-3 and 4-5-6 are scrambled by the aldolase and triosephosphate isomerase reactions, additional exchange of hydrogens at positions 1 and 2 must have occurred before these steps. The value of the coefficient that relates site 2 of glucose to site I of ethanol in particular can be used to quantify the contribution of intermolecular exchange occurring in the course of the transfer from site 2 of glucose 6-phosphate to site 1 of fructose 6-phosphate mediated by phosphoglucoisomerase. The average hydrogen isotope effects associated with the transfer of hydrogen from the water pool to the methyl or methylene site of ethanol are estimated. In contrast to conventional experiments carried out in strongly deuterium-enriched media where metabolic switching may occur, the NMR investigation of site-specific natural isotope fractionation, which operates at tracer isotopic abundance, faithfully describes the unperturbed metabolic pathways.

Deuterium↗
PubMed1995

Isolation of black creek canal virus, a new hantavirus from Sigmodon hispidus in Florida.

Numerous rodents were trapped for serologic and virologic studies following the identification of a hantavirus pulmonary syndrome (HPS) case in Dade County, Florida. Cotton rats (Sigmodon hispidus) were the most frequently capture rodent and displayed the highest seroprevalence to a variety of hantavirus antigens. Hantavirus genome RNA was detected in all the seropositive cotton rats tested, using a reverse transcriptase-polymerase chain reaction (RT-PCR) assay. A virus was isolated from tissues of two seropositive cotton rats by cultivation of lung and spleen homogenates on Vero E6 cells. Nucleotide sequence information obtained by direct RT-PCR and the serologic relationships of this virus with the other hantaviruses indicate that this virus, Black Creek Canal virus, represents a new hantavirus distinct from the previously known serotypes.

Animals↗
PubMed1995

Sexual knowledge interview schedule: reliability.

The Sexual Knowledge Interview Schedule (SKIS) is a 46-item interview schedule with an abuse scale and knowledge scale. The knowledge scale includes feelings, body parts identification, body parts function and general sexual knowledge. The reliability of the SKIS is reported. Internal consistency for scales/subscales ranges from 0.78 to 0.96. Inter-rater reliability was 95.3% agreement and test-retest reliability was 70.1%.

Adolescent↗
PubMed1994

Increased risk of small intestinal atresia among twins in the United States.

OBJECTIVE: To compare the prevalence of small intestinal atresia among twins and singletons in the United States. DESIGN: Descriptive analysis. MEASUREMENTS: The McDonnell Douglas Health Information System (MDHIS), a national registry of newborn diagnoses, 1982 through 1988; and the Metropolitan Atlanta Congenital Defects Program (MACDP), a registry of defects among infants in Atlanta, 1968 through 1989. PATIENTS: Live-born infants with small intestinal atresia. INTERVENTIONS: None. MAIN RESULTS: In both systems, the rate of small intestinal atresia was higher among twins than singletons (MDHIS: 5.5 per 10,000 vs 2.0, relative risk [RR] = 2.8, 95% confidence interval [CI] = 1.9 to 4.0; MACDP: 7.3 vs 2.5, RR = 2.9, 95% CI = 1.5 to 5.7). The increase was more notable among same-sex twins than opposite-sex twins, suggesting an increase among monozygotic twins. It was also more notable among twins with jejunoileal atresia than those with duodenal atresia, suggesting a vascular cause in many cases. CONCLUSION: Twins have a higher rate of small intestinal atresia than singletons, possibly due to vascular disruption in monozygotic twins.

Databases, Factual↗
PubMed1994

Effects of estrogen on free fatty acid metabolism in humans.

To determine whether estrogen directly affects effective adipose lipolysis, palmitate rate of appearances ([14C]palmitate) was measured in 15 postmenopausal women. Each volunteer was studied after > or = 2 mo of estrogen treatment and again after > or = 2 mo of estrogen deficiency. Plasma hormone concentrations were controlled and identical on the 2 study days with use of the pancreatic clamp technique, and the lipolytic response to epinephrine and epinephrine + phentolamine was assessed. Results showed that overall palmitate flux was greater (10-20%, P < 0.05) during the estrogen-deficient than during the estrogen-replete study. Adrenergic stimulation of lipolysis was not specifically influenced by estrogen treatment, and control of plasma hormone concentrations did not eliminate the difference in palmitate flux between the estrogen-deficient and estrogen-replete study days. We conclude that estrogen deficiency is associated with increased plasma free fatty acid availability and that estrogen likely has direct, albeit small, effects on adipose tissue lipolysis.

Blood Glucose↗
PubMed1993

Descriptive epidemiology of small intestinal atresia, Atlanta, Georgia.

To describe the epidemiology of small intestinal atresia (SIA) in Atlanta, Georgia, from 1968 through 1989, we used the Metropolitan Atlanta Congenital Defects Program, an active, population-based surveillance system for birth defects diagnosed during the first year of life. We identified 176 infants with SIA, a prevalence of 2.8 per 10,000 livebirths. Among black infants, the prevalence was 3.7 per 10,000 livebirths, significantly higher than the prevalence of 2.4 per 10,000 among white infants [relative risk (RR) = 1.6, 95% confidence interval (CI) = 1.1,2.1]. Nine infants were each one member of a unique pair of twins. The prevalence among twin infants was 7.3 per 10,000, significantly higher than the prevalence of 2.8 per 10,000 among singletons (RR = 2.7, 95% CI = 1.4,5.2). Forty-nine percent of the infants had duodenal atresia, 36% had jejunal atresia, and 14% had ileal atresia. Two infants (1%) had atresia at an unspecified site in the small intestine. We grouped the infants by anatomic location of SIA into four categories: isolated SIA (53%), SIA with multiple unrelated defects (21%), sequences (16%), and syndromes (10%). We then compared the isolated and multiple unrelated defects groups by gender, race, maternal age, birth weight and one-year mortality for each location of SIA. Among black infants the prevalence of isolated jejunal atresia was 1.4 per 10,000, significantly higher than the prevalence of 0.2 per 10,000 among white infants (RR = 6.3, 95% CI = 2.9, 13.5). The increased prevalence of these defects among twins was a particularly interesting finding.

Adolescent↗
PubMed1993

Antispasmodic activity of benzylisoquinoline alkaloids analogous to papaverine.

In vitro, reticuline, norarmepavine, coclaurine, and papaverine competitively antagonize the uterine muscular contractions induced by acetylcholine and calcium. The antagonism is more efficient for the alkaloid coclaurine which is even stronger than papaverine. The pA2 values obtained with each of the four alkaloids for both agents, acetylcholine and calcium, respectively, were as follows: reticuline (5.35 and 4.81), norarmepavine (5.55 and 4.09), coclaurine (7.42 and 6.91), papaverine (5.32 and 6.23). The two components, phasic and tonic, of the response of the vas deferens to potassium are reduced by the four alkaloids. The reduction is greater for the tonic phase, with the following IC50 values: reticuline 474 microM, norarmepavine 101 microM, coclaurine 68.9 microM, and papaverine 14.3 microM. The antispasmodic activity of the three alkaloids, similar to papaverine, is related to an inhibiting effect of extracellular calcium, an intracellular effect, or both.

Alkaloids↗
PubMed1993

Defining and classifying skin tears: need for a common language.

Very little has been written about skin tears. A common taxonomy and definition for each type of skin tear can organize teaching, practice, and research in the field. In 1990, Payne and Martin published the results of a descriptive clinical nursing research study on the epidemiology and management of skin tears in older adults. The Payne-Martin Classification System for Skin Tears, definitions, and characteristics of skin tears were presented. The purpose of this article is to critique their classification system and definitions. Criteria for evaluating taxonomies, internal validity, external validity, and utility, are used for the critique. A revision based upon continuing research and work with the classification system is presented. Further testing and modification will refine the classification and advance the science of wound care.

Humans↗
PubMed1992

Baculovirus expression of the glycoprotein gene of Lassa virus and characterization of the recombinant protein.

A recombinant baculovirus was constructed that expresses the glycoprotein gene of Lassa virus (Josiah strain) under the transcriptional control of the polyhedrin promoter. The expressed protein (B-LSGPC) comigrated with the authentic viral glycoprotein as observed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), was reactive with monoclonal antibodies (MAbs) in Western blots, and was glycosylated. Although the recombinant protein was not processed into the mature glycoproteins, G1 and G2, it demonstrated reactivity with all known epitopes as measured by indirect immunofluorescence (IFA), and it was immunogenic, eliciting antisera in rabbits that recognized whole virus in IFAs. Regarding future applications to diagnostic assays, the recombinant glycoprotein proved to be an effective substitute for Lassa virus-infected mammalian cells in IFAs and it was able to distinguish sera from several human cases of Lassa fever, against a panel of known negative sera of African origin, in an enzyme immunoassay (EIA).

Animals↗
PubMed1992

Trends in rates of multiple vascular disruption defects, Atlanta, 1968-1989: is there evidence of a cocaine teratogenic epidemic?

Research suggests that, perhaps through mechanisms initiated by vasoconstriction and leading to vessel thrombosis or embolism, cocaine causes vascular disruption defects, and that frequent cocaine use during early pregnancy could disrupt multiple organ systems in the fetus. We hypothesized that if cocaine is an important cause of multiple vascular disruption defects, a rising prevalence of cocaine use by mothers during pregnancy should be accompanied by rising rates of these defects in their offspring. Using data from the Metropolitan Atlanta Congenital Defects Program, we identified all infants born in Atlanta from 1968 through 1989 who had nonsyndromic, provisional vascular disruption defects affecting more than one organ system: 61 infants (78%) had gastrointestinal and genitourinary defects, 7 (9%) had gastrointestinal and abdominal wall defects, 2 (3%) had gastrointestinal and limb reduction defects, 2 (3%) had limb reduction and abdominal wall defects, 2 (3%) had central nervous system and gastrointestinal defects, 2 (3%) had genitourinary and limb reduction defects, 1 (1%) had genitourinary and abdominal wall defects, and 1 (1%) had central nervous system and genitourinary defects. The prevalence of Atlanta infants with more than one vascular disruption defect is 0.13 per 1,000 live births. Chi-square analysis for trends showed no increase in prevalence during the study period. Our data are from one of the first population-based studies in which trends for defects potentially caused by maternal cocaine use are examined; the results of our study show no significant change in the prevalence of multiple vascular disruption defects over time.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Drug-Induced↗
PubMed1992

Cocaine and single ventricle: a population study.

A recent case report by Shepard et al. (Teratology 43:113-117, 1991) suggested that single ventricle may result from maternal cocaine ingestion by inducing coronary occlusion in the developing fetal heart. We used data from the Atlanta Birth Defects Case-Control Study and the Metropolitan Atlanta Congenital Defects Program (MACDP) to investigate the role of maternal cocaine ingestion in the induction of single ventricles. We identified through the MACDP 58 case infants with a single ventricle, 27 who were study subjects in the Atlanta Birth Defects Case-Control Study, and 31 who were not. We conducted a case-control study with the 27 Atlanta Birth Defects Case Control Study infants, frequency-matched to control infants by race, hospital of birth, and calendar quarter of birth. None of the 27 case infants were exposed to cocaine during early pregnancy, but 7 (0.43%) of the control infants were exposed during early pregnancy. Using MACDP data, we conducted an analysis of trends for prevalence of single ventricle in the metropolitan area. No upward trend in single ventricle was detected for 1968 through 1990. Our data suggest that even if maternal cocaine ingestion during pregnancy is a cause of single ventricle, most cases appear to be unrelated to this exposure.

Abnormalities, Drug-Induced↗
PubMed1992

Alternative approaches to nursing practice: application of Peplau, Rogers, and Parse.

This article demonstrates three major nursing theories in practice. The uniqueness of each theory is clarified through the presentation of nursing formulations and practice implications. The discussion provides a metaperspective of how practice based in nursing theory is different from traditional practice and how nursing theory can guide practice.

Humans↗
PubMed1991

Determination of site-specific carbon isotope ratios at natural abundance by carbon-13 nuclear magnetic resonance spectroscopy.

Site-specific natural isotope fractionation of hydrogen studied by deuterium NMR (SNIF-NMR) spectroscopy is a powerful source of information on hydrogen pathways occurring in biosyntheses in natural conditions. The potential of the carbon counterpart of this method has been investigated and compared. Three typical molecular species, ethanol, acetic acid, and vanillin, have been considered. Taking into account the requirements of quantitative 13C NMR, appropriate experimental procedures have been defined and the repeatability and reproducibility of the isotope ratio determinations have been checked in different conditions. It is shown that the carbon version of the SNIF-NMR method is capable of detecting small differences in the carbon-13 content of the ethyl fragment of ethanols from different botanical or synthetic origins. These results are in agreement with mass spectrometry determinations of the overall carbon isotope ratios. Deviations with respect to a statistical distribution of 13C have been detected in the case of acetic acid and vanillin. However, since the method is very sensitive to several kinds of systematic error, only a relative significance can be attached at present to the internal parameters directly accessible. Isotope dilution experiments have also been carried out in order to check the consistency of the results. In the present state of experimental accuracy, the 13C NMR method is of more limited potential than 2H SNIF-NMR spectroscopy. However it may provide complementary information. Moreover it is particularly efficient for detecting and quantifying adulterations that aim to mimic the overall carbon-13 content of a natural compound by adding a selectivity enriched species to a less expensive substrate from a different origin.

Acetates↗
PubMed1991

The anticonvulsant valproate teratogen restricts the glial cell cycle at a defined point in the mid-G1 phase.

Direct cell counting and extent of [3H]thymidine incorporation demonstrated valproate to inhibit C6 glioma proliferation rate in a dose-dependent manner with a 1 mM concentration achieving 50% inhibition. The antiproliferative effect was reversible and could not be attributed to cytotoxicity at the valproate concentrations employed. The site of valproate action within the cell cycle was determined to be in the G1 phase, at a point 6-6.5 h prior to S phase, by estimating the time to increased [3H]thymidine incorporation following release from a 70% proliferative arrest. Synchronised cells obtained by a mitotic selection procedure required 11-12 h to enter S phase and demonstrated the valproate restriction point to be 5 h into the G1 phase of the C6 cell cycle. Exposure of valproate to the part of the G1 period which follows the restriction point was without effect on cell entry into S phase.

Animals↗
PubMed1991

Are offspring of women with hereditary hematologic disorders at increased risk of congenital cardiovascular malformations?

Hereditary hematologic disorders (HHD) have been reported in excess among infants and families of infants with congenital cardiovascular malformations (CCM) compared with controls, suggesting possible common pathogenetic mechanisms. It is plausible that hemodynamic changes during pregnancy associated with HHD could affect cardiac morphogenesis. To investigate whether offspring of women with selected HHD have an excess risk of CCM, the authors examined data from a nationwide birth defects monitoring program (BDMP) covering about 2.9 million births in the United States between 1982 and 1988. The system ascertains major birth defects diagnosed in the newborn period. An anonymous linkage procedure linked maternal obstetric records with newborn records using demographic, diagnostic, and geographic variables. A total of 1,239 mothers were identified with selected HHD (47 hereditary spherocytosis, 575 thalassemias, 310 sickle cell anemia, 88 other hereditary hemolytic anemias, 159 von Willebrand disease, and 60 other congenital coagulopathies). In all, 14 infants received a newborn discharge diagnosis of CCM (expected number based on population rates of CCM from the same hospitals and time period is 7.74; P = 0.0268). No single CCM entity accounted for this excess. In contrast, 8 infants had major non-CCM defects (expected number 7.46; P = 0.466). These data suggest an excess risk of CCM among offspring of women with selected HHD. Further studies are needed to explore these findings and to evaluate the pathogenetic significance of this association.

Epidemiologic Methods↗