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Biomedical subjects

J M Martin

Publications and source records attributed to J M Martin.

At least 55 records · Page 3Linked to original sources
PubMed1999

Conserved polymerase chain reaction primers fail in diagnosis of parasitic infections.

We demonstrate that a set of previously described polymerase chain reaction primers used for detection of hemogregarines in reptiles will also amplify the same region of the 18S rRNA gene of reptiles, amphibians, mammals, and insects and thus should not be used for molecular diagnosis. These same primers have also been used to differentiate 2 species of Plasmodium that infect lizards. We provide evidence that the observed variance may have been dependent on parasitemia and not representative of actual molecular differences between the 2 parasite species.

Animals↗
PubMed1999

Acceptability and safety of a new 3.0 ml re-usable insulin pen (HumaPen) in clinical use.

A new re-usable insulin pen (the HumaPen) was tested in a multinational study in patients with Type 1 (45.1%) or Type 2 (54.9%) diabetes. Prior to study entry, patients used either syringes or a comparison pen. Patients changed to the HumaPen for all insulin injections during the 5-to 7-week study and a 12- to 13-week extension period. Acceptability of the HumaPen was assessed from a questionnaire completed at the end of the study by 72 previous syringe users and 209 previous pen users. HumaPen features considered easy/very easy by pre-study syringe users or pre-study pen users were correcting a mis-dialled dose (97.2%; 95.1%, respectively), reading the dose numbers (95.8%; 97.1%) and ease of learning (95.8%; 92.3%). Convenience, comfort and ease of use were stated to be better by a majority of pre-study syringe users and similar by pre-study pen users. At the end of the initial study, 73.6% of syringe users and 55.5% of previous pen users said they would continue to use the HumaPen, and 171 patients continued into the extension. As expected, the most common adverse event was hyperglycaemia but the majority were mild and none caused discontinuation from HumaPen use. The main reason for not continuing into the extension period, and for return of pens, was the injection force, which was subsequently reduced by modification of design and production prior to launch. The HumaPen therefore appeared well accepted and safe in this global study and a majority said they would recommend it to other patients.

Adolescent↗
PubMed1998

Cytotoxic and insecticidal constituents of the unripe fruit of Persea americana.

Unripe avocado fruit (Persea americana) was subjected to a bioactivity-directed fractionation, as monitored via the brine shrimp lethality assay, to isolate three major bioactive constituents (1-3). Compounds 1-3 all have a 1,2,4-triol moiety and a long aliphatic chain that terminates as either an alkane, alkene, or alkyne, respectively; 1 is new, while 2 and 3 have been described previously but not as cytotoxic or pesticidal agents. All have activity against six human tumor cell lines in culture and show selectivity for human prostate adenocarcinoma (PC-3) cells with 3 being nearly as potent as adriamycin. Also, when tested against yellow fever mosquito larva, 3 was more effective than rotenone, a natural botanical insecticide and positive control.

Aedes↗
PubMed1998

Adhesion-related glycocalyx study: quantitative approach with imaging-spectrum in the energy filtering transmission electron microscope (EFTEM).

Large polysaccharide molecules composing the glycocalyx have been shown to prevent cell adhesion. However, this process was not observed microscopically. Terbium labeling, combined with a new quantitative imaging method based on electron energy loss spectroscopy, allowed specific glycocalyx staining with excellent contrast. Image analysis enabled us to compare glycocalyx structure in free membrane areas and contacts between monocytic cells and bound erythrocytes. Apparent glycocalyx thickness, in contact areas, was half of the sum of glycocalyx thicknesses in free areas without label density increase. Ultrastructural immunogold localization of CD43 molecules, a major component of glycocalyx, was also demonstrated to be excluded from contact areas during adhesion. Thus, both approaches strongly suggest that some glycocalyx elements must exit from contact to allow binding of adhesion molecules.

Antigens, CD↗
PubMed1998

Are cognitive errors of underestimation predictive or reflective of depressive symptoms in children: a longitudinal study.

Children in Grades 3-8 participated in a longitudinal study of the relation between negative self-evaluation errors and symptoms of depression. Children's self-perceived competence in 5 domains (academic, social, athletic, appearance, and conduct) was compared with teachers' and peers' perceptions. Children's tendency to underestimate their competencies predicted increases in depression scores in only 1 of 6 grade levels. Children's depression scores predicted increases in the underestimation of self-competence over time in all grade levels. Gender differences and developmental differences in the cognitive errors associated with depression scores also emerged. Contrary to A. T. Beck's (1963, 1972) model, negative self-distortions appear to be more reflective than predictive of depression in children.

Adolescent↗
PubMed1998

A longitudinal look at the relation between depression and anxiety in children and adolescents.

Elementary school students (n = 330) and their parents (n = 228) participated in a 3-year longitudinal study of the temporal relation between anxiety and depressive symptoms in children. Every 6 months, children and parents completed depression and anxiety questionnaires for a total of 6 waves. Structural equation modeling revealed that individual differences on all measures were remarkably stable over time. Nevertheless, high levels of anxiety symptoms at 1 point in time predicted high levels of depressive symptoms at subsequent points in time even after controlling for prior levels of depression symptoms. These findings were consistent across self- and parent reports. Results support the temporal hypothesis that anxiety leads to depression in children and adolescents.

Adolescent↗
PubMed1998

Field inversion gel electrophoresis as a typing system for group A streptococcus.

Field inversion gel electrophoresis (FIGE) was performed on 139 isolates of group A streptococcus (GAS) representing 72 different M types. Multiple isolates were tested for 27 M types (range, 2-19). Each of the M types tested had at least one unique banding pattern that was not observed in any other M type. For 23 of 27 M types for which multiple isolates were available, band profiles of the isolates were the same or differed by < 3 bands and are considered indistinguishable or closely related. These data demonstrate that FIGE of the DNA of GAS identifies differences between and within M types.

Bacterial Typing Techniques↗
PubMed1997

Early detection of the lytic LMP-1 protein in EBV-infected B-cells suggests its presence in the virion.

The Epstein-Barr virus (EBV)-positive B958 cell line expresses two related membrane proteins encoded by BNLF-1 open reading frames. One protein (LMP-1) has been shown to be essential for the growth transforming properties of EBV. The second protein (the lytic LMP-1) is an amino-terminally truncated form of LMP-1 whose expression is associated with induction of EBV's lytic cycle. We have investigated the expression of full-length and lytic forms of LMP-1 immediately after infection of the EBV-negative, B-lymphoma cell line BJAB. Only the lytic LMP-1 protein is present in BJAB cells early (within minutes following addition of virus) after infection with virus derived from either uninduced or tetradecanoyl phorbol acetate and sodium butyrate-induced B958 cells. Lytic LMP-1 protein levels begin to decline by 48 hr after infection, whereas levels of full-length LMP-1 increase between 24 and 48 hr after infection and then remain constant. The presence of the lytic LMP-1 protein in infected cells is independent of both protein synthesis and virus internalization. We also find the lytic LMP-1 protein in BJAB cells early after infection (within 3 hr of addition of virus) with the HH514 strain of EBV, and HH514 cells treated with tetradecanoyl phorbol acetate and sodium butyrate, express high levels of both the lytic LMP-1 and full-length LMP-1 proteins. The lytic LMP-1 protein is enriched in purified virion preparations, and immunoelectron microscopic analysis indicates that EBV virions can be specifically labeled with anti-LMP-1 antisera. Together, these results are consistent with a model in which the lytic LMP-1 protein is present in the EBV virion and is carried into the B-cell upon infection and suggest a role for this protein in early infection events and/or in EBV's lytic cycle.

Animals↗
PubMed1997

A software for the description of workplaces in the PRS system.

Workplace description is an operation indispensable for the identification of professional risks and, in fulfillment of that objective, can best be accomplished by listing the constituent tasks associated with each job. This article presents a software in Visual-Basic to be run on a portable micro-computer, which facilitates this process according to these aims. The occupational physician and safety engineer can make good use of the exposure database resulting from the application of this program. Job histories are built automatically, while workers with similar exposures are grouped together and job-exposure matrices are elaborated. This information, computerized, sorted and re-assembled, can then be used effectively for studies in the field of occupational epidemiology.

Epidemiologic Methods↗
PubMed1997

Infective endocarditis: 35 years of experience at a children's hospital.

We review the predisposing conditions, the presenting signs and symptoms, as well as the risk factors and bacterial etiologies in children with infective endocarditis, focusing on hospital course and outcome. We conducted a retrospective analysis of 76 cases of endocarditis in 73 patients occurring at Children's Hospital of Pittsburgh from January 1958 through December 1992. The median age of the patients was 9 years (range, 1 month to 18 years). Predisposing conditions included congenital heart disease (62 patients) and rheumatic heart disease (four patients). Seventy-seven percent of the children with congenital heart disease had undergone cardiac surgery. After therapy with appropriate antibiotics was started, blood cultures for 67 patients (70 episodes of infective endocarditis) remained positive for a mean (+/-SD) of 0.7 +/- 1.41 days, and all patients who presented with fever (75 episodes in 72 patients) remained febrile for a mean (+/-SD) of 4.28 +/- 6.21 days. Secondary fever occurred in 39% of the children. Thirty (41%) of the 73 patients survived without any complications and 13 (18%) died. Fifteen children with complications required surgery. Children with endocarditis caused by Staphylococcus aureus were more likely than those with infection caused by viridans streptococci to have prolonged fever, secondary fever, and/or complications as well to require surgery.

Adolescent↗
PubMed1997

A competency-based model of child depression: a longitudinal study of peer, parent, teacher, and self-evaluations.

In a two-wave longitudinal study of third and sixth graders (N = 617), we obtained self-reports of depression and peer, teacher, parent, and self-reports of competence in five domains: academic, social, attractiveness, conduct, and athletic. Competency evaluations by others predicted change in self-perceived competence over time for girls, but not for boys. Depression predicted change in self-perceived competence over time for boys but not for girls. Among girls, the relative importance of parent, teacher, and peer appraisals shifted from third to sixth grade. For both boys and girls, self-perceptions of competence predicted change in depression scores over time. Furthermore, self-perceived competencies mediated the relation between competency appraisals by others and children's self-reported depression. Results are interpreted in light of a competency-based model of child depression.

Adolescent↗
PubMed1996

Role of alpha v beta 5 and alpha v beta 6 integrin glycosylation in the adhesion of a colonic adenocarcinoma cell line (HT29-D4).

We have previously characterized the expression of the alpha nu beta 5 and alpha nu beta 6 integrins as major receptors for the human colonic adenocarcinoma cell line (HT29-D4), on vitronectin and fibronectin, respectively [Lehmann et al. (1994): Cancer Res 54:2102-2107]. In the present work we investigated the glycosylation role of these integrins in their adhesive functions. To this end, we used glycohydrolases to show that cell surface integrins were N-glycosylated and sialylated, and that only the alpha v subunit carried some immature oligosaccharide side chains. To alter the glycosylation state of the cell surface alpha v beta 5 and alpha v beta 6 integrins, we used two oligosaccharide-processing inhibitors: 1-deoxymannojirimycin (dMNJ) and tunicamycin (TM). Following treatment of HT29-D4 cells with dMNJ, cell surface alpha v beta 5 and alpha v beta 6 carried only high-mannose-type sugar chains, while TM-treated cells expressed de-N-glycosylated integrins. Neither alpha/beta heterodimers assembly nor cell surface expression were impaired in the presence of the drugs. Finally, we established that adhesion of dMNJ- or TM-treated cells was altered on both vitronectin and fibronectin substrata, whereas the adhesion of these cells on laminin or collagen type I was virtually unchanged.

1-Deoxynojirimycin↗
PubMed1996

Modeling causal relations between academic and social competence and depression: a multitrait-multimethod longitudinal study of children.

The authors obtained self-reports, peer nominations, teacher ratings, and parent reports of depression and social and academic competence on 490 3rd graders and 455 6th graders near the beginning and end of the school year. Confirmatory factor analysis and structural equation modeling revealed that (a) measures showed significant convergent and discriminant validity; (b) within-wave correlations between constructs were large and significant, although the depression-social competence correlation was larger than the depression-academic competence correlation; (c) the cross-wave stability of all constructs was remarkably high; and (d) social competence at Wave 1 predicted depression at Wave 2 for 6th graders after controlling for depression at Wave 1. Depression did not predict change in either academic or social competence over time. Implications for competence-based and failure-based models of child depression are discussed.

Achievement↗
PubMed1996

Monoclonal antibodies to surface antigens of Mycobacterium tuberculosis and their use in a modified enzyme-linked immunosorbent spot assay for detection of mycobacteria.

Three monoclonal antibodies (MAbs) were generated from splenocytes of a BALB/c mouse immunized with heat-killed Mycobacterium tuberculosis. All three MAbs bound to surface epitopes of M. tuberculosis as shown by whole-cell enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence, and immunoelectron microscopy. One immunoglobulin M (IgM) MAb bound to lipoarabinomannan, the second IgM MAb bound to mycolyl-arabinogalactan-peptidoglycan complex, and the third MAb, an IgG3, bound to a surface epitope of an uncertain nature. The MAbs demonstrated different cross-reactivity patterns with other mycobacteria. Two of the MAbs were used to develop a modified ELISA spot assay for the detection of mycobacteria.

Animals↗
PubMed1996

Molecular characterization of replication-competent variants of adenovirus vectors and genome modifications to prevent their occurrence.

Adenovirus (Ad) vectors for gene therapy are made replication defective by deletion of E1 region genes. For isolation, propagation, and large-scale production of such vectors, E1 functions are supplied in trans from a stable cell line. Virtually all Ad vectors used for clinical studies are produced in the 293 cell, a human embryonic kidney cell line expressing E1 functions from an integrated segment of the left end of the Ad type 5 (Ad5) genome. Replication-competent vector variants that have regained E1 sequences have been observed within populations of Ad vectors grown on 293 cells. These replication-competent variants presumably result from recombination between vector and 293 cell Ad5 sequences. We have developed Ad2-based vectors and have characterized at the molecular level examples of replication-competent variants. All such variants analyzed are Ad2-Ad5 chimeras in which the 293 cell Ad5 E1 sequences have become incorporated into the viral genome by legitimate recombination events. A map of Ad5 sequences within the 293 cell genome developed in parallel is consistent with the proposed recombination events. To provide a convenient vector production system that circumvents the generation of replication-competent variants, we have modified the Ad2 vector backbone by deleting or rearranging the protein IX coding region normally present downstream from the E1 region such that the frequency of recombination between vector and 293 cell Ad5 sequences is greatly reduced. Twelve serial passages of an Ad2 vector lacking the protein IX gene were carried out without generating replication-competent variants. In the course of producing and testing more than 30 large-scale preparations of vectors lacking the protein IX gene or having a rearranged protein IX gene, only three examples of replication-competent variants were observed. Use of these genome modifications allows use of conventional 293 cells for production of large-scale preparations of Ad-based vectors lacking replication-competent variants.

Adenovirus E1 Proteins↗
PubMed1994

Use of in vivo complementation in Mycobacterium tuberculosis to identify a genomic fragment associated with virulence.

Novel molecular tools and genetic methods were developed to isolate genomic fragments of Mycobacterium tuberculosis that may be associated with virulence. We sought to restore virulence, a characteristic of M. tuberculosis that is correlated with growth rate in mouse spleen and lung tissue, to the avirulent strain H37Ra by complementation. A representative library of the virulent M. tuberculosis strain H37Rv was constructed and transformed into H37Ra. Enrichment for individual faster-growing recombinants was achieved by passage of pools of H37Ra transformants harboring the H37Rv library through mice. A molecular strategy was devised to isolate and clone the H37Rv genomic DNA fragment ivg, which conferred a more rapid in vivo growth rate to H37Ra.

Animals↗