Search PubMed⌕ Search

Biomedical subjects

S L Martin

Publications and source records attributed to S L Martin.

At least 73 records · Page 4Linked to original sources

Mental health problems of children of migrant and seasonal farm workers: a pilot study.

OBJECTIVE: Children of migrant and seasonal farm workers constitute important populations for study because they chronically experience extreme poverty and parental unemployment. Also, migrant children are exposed to chronic residential and school mobility. METHOD: Mothers and children were interviewed using the Diagnostic Interview Schedule for Children Version 2.1. RESULTS: The results indicated that 66% of the children had one or more psychiatric diagnoses based on mother or child reports, with anxiety disorders being the most prevalent diagnosis. CONCLUSIONS: These findings suggest the need for a larger, epidemiological study of the psychiatric morbidity of rural children of farm workers.

Child↗

Eicosanoid production from porcine neutrophils and platelets: differential production with various agonists.

Polymorphonuclear neutrophils (PMN) and platelets interact to produce both inflammatory and anti-inflammatory lipid mediators during human disease. Because swine models of human disease are used, it is important to understand the mechanisms involved in the formation of lipid mediators from porcine PMN-platelet interactions. In the present study, we investigated the mechanism of thromboxane (Tx) A2 and lipoxin A4 (LXA4) formation from porcine PMN and platelets, respectively. PMN (10(7)/ml) and platelet (30 x 10(7)/ml) suspensions stimulated with porcine C5a (pC5a), but not recombinant human C5a (rhC5a), significantly enhanced TxB2 formation. After cytochalasin B treatment, pC5a or rhC5a significantly and equally enhanced TxB2 formation from PMN-platelet suspensions. A-23187-induced TxB2 formation from platelets was not significantly augmented by the presence of PMN in these suspensions. A-23187 induced significant LXA4 production from porcine PMN that was not augmented by addition of platelets. Flow cytometric analysis of PMN-platelet suspensions revealed activated platelets adherent to PMN following pC5a stimulation. CV-6209, a platelet-activating factor (PAF) receptor antagonist, dose dependently prevented pC5a-induced platelet adherence to PMN and TxB2 formation. These data demonstrate that 1) porcine PMN alone can biosynthesize LXA4 without the assistance of platelets, which is in sharp contrast to human PMN-platelet interactions, and 2) in the absence of cytochalasin B, pC5a stimulates PAF biosynthesis from porcine PMN, resulting in TxB2 formation from platelets.

Animals↗

Is incarceration during pregnancy associated with infant birthweight?

OBJECTIVES: This study examined whether incarceration during pregnancy is associated with infant birthweight. METHODS: Multivariable analyses compared infant birthweight outcomes among three groups of women: 168 women incarcerated during pregnancy, 630 women incarcerated at a time other than during pregnancy, and 3910 women never incarcerated. RESULTS: After confounders were controlled for, infant birthweights among women incarcerated during pregnancy were not significantly different from women never incarcerated; however, infant birthweights were significantly worse among women incarcerated at a time other than during pregnancy than among never-incarcerated women and women incarcerated during pregnancy. CONCLUSIONS: Certain aspects of the prison environment (shelter, food, etc.) may be health-promoting for high-risk pregnant women.

Adult↗

Children of farm laborers: utilization of services for mental health problems.

Utilization of various types of services for children's mental health problems was examined among 112 agricultural farm worker families. Pairs of mothers and children (aged 8 to 11) were interviewed using the Diagnostic Interview Schedule for Children and the Child and Adolescent Services Assessment. Sixty-four percent of the children met criterion for one or more psychiatric diagnoses. Children with a psychiatric diagnosis were five times more likely to see a health professional for a mental health problem compared to children without a psychiatric diagnosis However, less than half of the children with a psychiatric diagnosis saw a health professional for their mental health problems. Families also consulted with school professionals, religious leaders, and non-professionals (such as friends) concerning their children's mental health, but families of children who had a psychiatric diagnosis were not significantly more likely to report these types of consultations than were families of children who did not have a psychiatric diagnosis. These findings are discussed in terms of recommendations for improving the mental health service delivery system for rural children.

Adolescent↗

Use of a supracondylar nail for treatment of a supracondylar fracture of the femur following total knee arthroplasty.

Treatment of displaced or comminuted supracondylar fractures of the femur following total knee arthroplasty is challenging and problematic. Closed treatment has been associated with malunion, nonunion, and loss of motion, whereas early operative treatment has been associated with infection as well as nonunion. Intramedullary fixation of these fractures has the theoretical advantage of preserving periosteal blood supply while allowing early motion. The use of a nail specifically designed for supracondylar femur fractures to treat a a periprosthetic fracture about a well-fixed total knee arthroplasty is reported. This device provides a valuable treatment option to the surgeon treating this difficult problem.

Aged↗

Response of African-American adolescents in North Carolina to gun carrying by school mates.

This study examined adolescents' perceptions concerning the presence of guns in their school and the adolescents' emotional and behavioral responses associated with these perceptions. Survey data from 376 African-American sixth, seventh, and eighth grade students of a low-income area of a North Carolina city were studied. Twenty-eight percent of adolescents reported that other students brought guns to school, 36% felt afraid that someone would hurt or attack them while at school, 15% avoided school (or places in school) because of fear that a student would hurt or attack them, and 20% carried weapons to school for self-protection. Logistic regression analyses found that, compared to their peers, adolescents who perceived that their school mates brought guns to school were almost twice as likely to experience fear while at school, were more than three times more likely to exhibit school avoidance behavior, and were more than twice as likely to bring a weapon to school themselves for self-protection. Educators and school health professionals are urged to work together to address these problems concerning school safety.

Adolescent↗

Galactofuranose biosynthesis in Escherichia coli K-12: identification and cloning of UDP-galactopyranose mutase.

We have cloned two open reading frames (orf6 and orf8) from the Escherichia coli K-12 rfb region. The genes were expressed in E. coli under control of the T7lac promoter, producing large quantities of recombinant protein, most of which accumulated in insoluble inclusion bodies. Sufficient soluble protein was obtained, however, for use in a radiometric assay designed to detect UDP-galactopyranose mutase activity (the conversion of UDP-galactopyranose to UDP-galactofuranose). The assay is based upon high-pressure liquid chromatography separation of sugar phosphates released from both forms of UDP-galactose by phosphodiesterase treatment. The crude orf6 gene product converted UDP-[alpha-D-U-14C]-galactopyranose to a product which upon phosphodiesterase treatment gave a compound with a retention time identical to that of synthetic alpha-galactofuranose-1-phosphate. No mutase activity was detected in extracts from cells lacking the orf6 expression plasmid or from orf8-expressing cells. The orf6 gene product was purified by anion-exchange chromatography and hydrophobic interaction chromatography. Both the crude extract and the purified protein converted 6 to 9% of the UDP-galactopyranose to the furanose form. The enzyme was also shown to catalyze the reverse reaction; in this case an approximately 86% furanose-to-pyranose conversion was observed. These observations strongly suggest that orf6 encodes UDP-galactopyranose mutase (EC 5.4.99.9), and we propose that the gene be designated glf accordingly. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified UDP-galactopyranose mutase revealed one major band, and analysis by electrospray mass spectrometry indicated a single major species with a molecular weight of 42,960 +/- 8, in accordance with that calculated for the Glf protein. N-terminal sequencing revealed that the first 15 amino acids of the recombinant protein corresponded to those expected from the published sequence. UV-visible spectra of purified recombinant enzyme indicated that the protein contains a flavin cofactor, which we have identified as flavin adenine dinucleotide.

Amino Acid Sequence↗

Preservation of intestinal gene expression during hibernation.

The role of luminal nutrients in regulating enterocyte gene expression was studied in a natural model for long-term fasting, the hibernating ground squirrel. Squirrels were studied during the active season and during the hibernation season when they had not eaten for at least 12 wk. The specific activities of sucrase, isomaltase, and intestinal alkaline phosphatase in jejunal brush-border membranes were similar in hibernating and active squirrels, whereas amino-oligopeptidase was reduced in hibernators. Na(+)-K(+)-adenosinetriphosphatase activity in jejunal mucosa was unchanged by hibernation. Densitometric analysis of Western blots showed that abundance of sucrase-isomaltase (SI), amino-oligopeptidase, and the Na(+)-glucose cotransporter SGLT1 was similar in the two activity states. Preservation of SI abundance in hibernation was confirmed by immunocytochemistry. Slot-blot analysis revealed no differences in mRNA levels for these proteins between hibernating and active squirrels. Enterocyte proliferation and migration rates were greatly suppressed in torpid squirrels but increased immediately upon rewarming during arousals. These results demonstrate the striking constancy of enterocyte gene expression despite long-term fasting in a hibernating mammal.

Adenosine Triphosphatases↗

Eosinophilia-induced vascular and airway remodeling and hyperresponsiveness in rat lungs.

We evaluated the effects of pulmonary infiltration of eosinophils without exogenous activators on airway and vascular hyperresponsiveness to muscarinic challenge in the lungs of rats infected with Toxocara [correction of Toxicara] canis, the canine round worm. Bronchoalveolar lavage of infected lungs produced 4.26 x 10(7) cells with 85% eosinophils, 15% mononuclear cells, and essentially no neutrophils. Eosinophils were present in the air spaces and interstitial spaces surrounding airways and vessels. The smooth muscle thickness increased about fourfold in large airways and vessels, and medium and small vessels were muscularized in infected lungs. In the T. canis-infected lungs, baseline airway resistance increased 288%, total vascular resistance (RT) increased 202%, and capillary filtration coefficient increased 208% compared with uninfected control lungs. Lung compliance was 56% of control. The concentration of acetylcholine that produced 50% of maximal response was 18.4 times greater for airway resistance and 18.7 times greater for RT in uninfected controls than in infected lungs. Isoproterenol (10(-4) M) decreased RT and peak airway pressure by 21% in infected lungs but had no significant effect on controls. We conclude that pulmonary interstitial infiltrates of eosinophils cause airway and vascular remodeling and increase baseline resistances and muscarinic reactivities of airways and vessels in rat lungs infected with T. canis.

Acetylcholine↗

Violence and substance use among North Carolina pregnant women.

OBJECTIVES: Prenatal patients were studied to examine the proportion of women who had been violence victims, women's patterns of substance use (cigarettes, alcohol, and illegal drugs) before and during pregnancy, and relationships between violence and substance use. METHODS: More than 2000 prenatal patients in North Carolina were screened for violence and substance use. Relationships between violence and patterns of substance use before and during pregnancy were examined, as well as women's continuation of substance use during pregnancy as a function of violence and sociodemographic factors. RESULTS: Twenty-six percent of the women had been violence victims during their lives. Before pregnancy, 62% of the women had used one or more substances; during pregnancy, 31% had used one or more substances. Both before and during pregnancy, violence victims were significantly more likely to use multiple substances than nonvictims. Continuation of substance use during pregnancy was significantly more likely among violence victims than nonvictims. CONCLUSIONS: Care providers should screen women for violence as well as for substance use and should ensure that women are provided with appropriate interventions.

Adult↗

Characteristics associated with pregnant women's utilization of substance abuse treatment services.

There is a dearth of substance abuse treatment programs available to pregnant substance-using women. However, even when specialized substance abuse treatment programs are offered to these high-risk women, some women will choose not to enter treatment. To gain a better understanding concerning the characteristics of pregnant substance-using women related to their decisions regarding treatment utilization, this study compares two groups of substance users: 93 pregnant women who accepted offered substance-related treatment services, and 89 pregnant women who declined the same services. All women were interviewed and information was gathered concerning their sociodemographic characteristics, their types and levels of substance use, substance use by their family members, and their experiences of being victims of violence. Bivariate analyses found that, compared to women who declined treatment, women who accepted treatment were more likely to be African-American, to be single (never married), and to have a significantly greater number of children. Bivariate analyses also showed that, compared to women who declined treatment, women who accepted treatment had more severe substance abuse problems and were more likely to have previously undergone treatment for a substance problem. Women who accepted treatment were twice as likely to have partners who used alcohol and were three times more likely to have experienced physical and/or sexual violence during pregnancy. When logistic regression procedures were used to simultaneously examine the relative impact of all of the variables on treatment utilization, the four strongest independent predictors positively associated with treatment utilization were the women's race (being African-American), the women's use of illegal drugs during pregnancy, the women's past treatment for substance abuse, and the women's use of cigarettes before pregnancy.

Adult↗

Substance use among incarcerated adolescents: associations with peer, parent, and community use of substances.

This study of incarcerated adolescents documents the number and proportion of incarcerated adolescents who use cigarettes, alcohol, and illegal drugs; examines substance use among the adolescents' peers, parents, and community members; and examines associations between incarcerated adolescents' use of substances and substance use by peers, parents, and community members. Questionnaire data indicated that substance use was common among incarcerated adolescents as well as among the adolescents' peers, parents, and community members. Logistic regression analyses revealed that, similar to patterns observed in the general population, peer substance use was the strongest predictor of substance use among incarcerated adolescents.

Adolescent↗

Total synthesis and expression in Escherichia coli of a gene encoding human tropoelastin.

To elucidate the structural features and interactions of tropoelastin (TEL) molecules which assist in giving the elastic fibre its physical properties, a 2210-bp synthetic human TEL-encoding gene (SHEL) was constructed for expression in Escherichia coli. To this end, a model of codon adjustment was tested which better suits the polypeptide biosynthetic needs of E. coli than the human sequence, where over one-third of this natural sequence contains expression-limiting rare codons and 4 amino acids alone account for 75% of the resulting polypeptide. This large synthetic TEL gene was expressed at a high level as the recombinant counterpart of human TEL and as a C-terminal fusion with glutathione S-transferase. This demonstrates that a synthetic approach based upon matching codon usage to that of the host organism can support significant expression of recombinant sequences. The synthetic gene incorporates the facility for simple cassette replacement in future insertion, deletion and mutagenesis experiments, including the introduction and removal of exon homologues. The resulting soluble polypeptide is easily purified and displays properties expected for this protein.

Amino Acid Sequence↗

Tightly regulated, developmentally specific expression of the first open reading frame from LINE-1 during mouse embryogenesis.

LINE-1 (L1) has achieved its status as a middle repetitive DNA family in mammalian genomes by duplicative transposition. Although transposition may occur in any cell type, expression and transposition of a full-length functional element in the germ line are necessary for evolutionarily significant propagation of L1. An immunohistochemical analysis of adult mouse ovaries and mouse postimplantation embryos revealed expression of L1 open reading frame 1 in the germ line as well as in steroidogenic tissues. These results demonstrate that L1 expression is controlled by a tightly regulated temporal and spatial program of events during development and imply that multiple loci of L1 in the mouse genome are active for expression.

Animals↗

Characterization of a LINE-1 cDNA that originated from RNA present in ribonucleoprotein particles: implications for the structure of an active mouse LINE-1.

Full-length, sense-strand, long interspersed element-1 (LINE-1 or L1) RNA is found as an RNA-protein complex in mouse embryonal carcinoma cells. Since this complex is a likely intermediate in LINE-1 transposition, its RNA may be enriched for the functional, or active, subset of mouse L1 sequences. For this reason, a cDNA library was constructed from RNA prepared from these ribonucleoprotein particles. The isolation and complete DNA sequence of one clone that is a strong candidate to be a functional version of mouse L1 is reported here. The structure of this element suggests a revision of the predicted sequence of an active mouse L1 and provides a tag that can be used to isolate its locus in the genome.

Animals↗

Polymorphic sequences encoding the first open reading frame protein from LINE-1 ribonucleoprotein particles.

The mouse LINE-1 (L1) retrotransposon contains two open reading frames (ORFs). Three classes of the protein encoded by the first open reading frame (ORF1) are expressed in the mouse embryonal carcinoma cell line, F9; the apparent molecular sizes of these proteins are 41.3, 43, and 43.5 kDa. Two of these three proteins (41.3 and 43 kDa) are translated in vitro from full-length, sense-strand L1 RNA isolated from ribonucleoprotein particles. A reverse transcription-polymerase chain reaction approach was used to clone the ORF1 region from RNA isolated from ribonucleoprotein particles, then the coding capacity of these clones was examined using in vitro transcription and translation. Multiple sequences that encode ORF1 were recovered by this approach, indicating that multiple loci of L1 in the mouse genome are expressed in F9 cells. In addition, L1 sequences with intact ORF1 regions appear to be selectively enriched in the ribonucleoprotein particles.

Animals↗

alpha 2-Macroglobulin gene expression during hibernation in ground squirrels is independent of acute phase response.

alpha 2-Macroglobulin, a major acute phase reactant in many species, increases in the Richardson's ground squirrel (Spermophilus richarsonii) during hibernation at the level of both mRNA and protein. To determine if the pattern of liver gene expression known as the acute phase response is elicited as a normal part of the physiological adaptation of hibernation, acute phase reactants were identified in the Richardson's ground squirrel and were then assayed for changes in mRNA expression in the livers of active and hibernating ground squirrels. Our data demonstrate that alpha 1-antitrypsin, alpha 2-macroglobulin, ceruloplasmin, C-reactive protein, and serum amyloid A are acute phase reactants in the Richardson's ground squirrel. Of these, only alpha 2-macroglobulin (alpha 2M) mRNA increases during hibernation, demonstrating that the entire acute phase response is not elicited as a part of the adaptation for hibernation. Alternatively, data from blood clotting assays of serum from active and hibernating animals support a role for the increase in alpha 2M protein during hibernation in decreasing the coagulative properties of the blood.

Actins↗

[Prenatal echographic diagnosis of esophageal atresia. Apropos ofa case].

We reported an antenatal diagnosis case of oesophageal atresia in 21 years aged woman in second pregnancy. The echographic diagnosis of antenatal oesophageal atresia was suspected from the non visualisation of stomach liquid after separate following examinations at 8 days interval, the presence of a great abundant hydramnios and a very important delay of in utero foetal growth. This study permitted us to emphasize the antenatal diagnosis interest in supporting a child with oesophageal atresia during neonatal period. The vital prognosis was essentially conditioned in this context of neonatal emergency by putting a feeding tube (cul-de-sac) and the absolute prohibition of any oral alimentation, waiting for the transfer of the child to a specialized institution.

Adult↗