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Biomedical subjects

S Henry

Publications and source records attributed to S Henry.

At least 37 records · Page 2Linked to original sources
PubMed1999

Malarial antibodies in Auckland blood donors.

AIM: To determine the malarial exposure characteristics of "malarial risk" blood donors and measure the potential infectivity of their donations using a commercially available malarial antibody screening kit. METHOD: Malarial risk donors were identified according to standard protocols, questioned as to their degree of exposure to malaria and blood samples were tested for malarial antibodies using an enzyme immunoassay kit. The kit used detects IgG antibodies to P. falciparum, shows 50% crossreactivity with P. vivax and some crossreactivity with P. ovale. Antibody positive samples were further checked by a direct immunochromatographic test for P. falciparum. RESULTS: We found 1.7% of the donors who were classified as a "malarial risk" to be positive for IgG malarial antibodies. None of these antibody positive samples was positive by the direct immunochromatographic test for P. falciparum. CONCLUSION: These results indicate that none of these donors tested were a risk of transmitting P. falciparum, the major and most serious cause of transfusion transmitted malaria. The introduction of malarial testing of malarial risk blood donors in Auckland, currently deferred for plasma donation only, could potentially recover 2300 units of red cells per year.

Animals↗
PubMed1999

Anatomical distribution of glycoprotein 93 (gp93) on nerve fibers during rat brain development.

Recent studies have implicated glycoconjugates on the membrane of growth cones as the necessary markers and intermediaries for axonal recognition, axonal motility, and pathway development. One such glycoconjugate, glycoprotein 93 (gp93), has been characterized, but the relative distribution of gp93 has yet to be described for the embryonic brain. In this study, the anatomical distribution of gp93 has been analyzed at embryonic day 15 (E15) and E18, and on postnatal day 3 in the rat by using a polyclonal gp93 antibody. Furthermore, fetal brain tissue transplanted into the adult rat eye has been tested for gp93 immunoreactivity, since central noradrenergic neurons in brainstem transplants are known to provide a continuous source of growing axons, even in adult tissue. In general, a greater abundance of gp93 immunoreactivity is apparent in the earlier embryonic stages (E15 and E18), whereas less is seen in the postnatal brain. The regions showing unique dispersal patterns of gp93 are the neuroepithelium, cerebral cortex, septo-hippocampal pathways, brainstem, and midbrain. This study has therefore focused on these areas and found implications for gp93 distribution appearing in the early development of specific neuronal pathways. Moreover, axons stain densely for gp93 within brain tissue transplants. The presence of gp93 in areas of extensive axonal outgrowth in the normal brain and in transplants suggests that this antibody is used as an early marker for axonal growth. Furthermore, gp93 might be used to map normal development in order to improve our understanding of diseases arising from developmental abnormalities.

Animals↗
PubMed1999

Resuscitation in the new millennium.

This article discusses resuscitation from a historical perspective; physiology; the optimal timing and volume for and fluids and endpoints of resuscitation; and the role of resuscitation in the future. Whether different types of victims of trauma should be resuscitated using different endpoints also is discussed.

Fluid Therapy↗
PubMed1999

Effects of glucagon in the control of endogenous glucose production in man.

Endogenous glucose production has been shown to increase during administration of glucagon + fructose, but not during administration of fructose alone. To determine the mechanisms by which glucagon exerts this action, endogenous glucose production (EGP) and gluconeogenesis from fructose (GNF) were measured in eight healthy subjects infused 1) with graded doses of glucagon (2 and 4 ng.kg-1.min-1 for 3 h each) during constant infusion of 13C-fructose (3 mg.kg-1.min-1), and 2) with graded doses of 13C-fructose (3 and 6 mg.kg-1.min-1) during constant glucagon infusion (2 ng.kg-1.min-1). GNF was estimated from 13C-glucose synthesis. In both protocols, infusion of 3 mg.kg-1.min-1 fructose + 2 ng.kg-1.min-1 glucagon increased EGP by 5-8% (P < 0.05), while GNF represented 43-49% of EGP. Thereafter, increasing the glucagon infusion rate further increased EGP to 118 +/- 3% of basal values (P < 0.01) without altering the proportion due to GNF. In contrast, increasing the fructose infusion rate at constant glucagonemia increased EGP similarly (by 19 +/- 4%, P < 0.05) but enhanced the contribution of GNF to 76 +/- 2% (P < 0.001). Graded infusion of glucagon or fructose alone failed to stimulate EGP. The present findings indicate that hyperglucagonemia stimulates endogenous glucose production during fructose infusion. This effect is not secondary to a stimulation of gluconeogenesis, but to a channelling of glucose-6-phosphate towards systemic release.

Adult↗
PubMed1999

Tuberculosis chemoprophylaxis using a liquid isoniazid-methadone admixture for drug users in methadone maintenance.

BACKGROUND: Tuberculosis is common in drug users, although compliance with therapy may be difficult in this population. OBJECTIVE: To evaluate an approach to enhancing compliance with tuberculosis chemoprophylaxis in drug users enrolled on methadone maintenance utilizing an isoniazid (INH)-methadone admixture. DESIGN: A prospective cohort study. SETTING: A drug treatment program in New Haven, Connecticut, USA. PATIENTS: Opioid-dependent drug users enrolled in methadone maintenance. INTERVENTION: Liquid isoniazid was mixed into subjects' daily dose of methadone. Vitamin B6 was given to subjects for self-administration. MEASUREMENTS AND MAIN RESULTS: Number of eligible subjects, reasons for not starting therapy, number starting therapy, proportion completing therapy and median duration of INH therapy were calculated. Thirty-nine subjects were eligible for INH chemoprophylaxis: 34 (87%) received INH mixed directly in their methadone and five (13%) had their INH consumption supervised by a nurse. Among these subjects, 72% (28/39) completed therapy. Among the 11 subjects who discontinued INH, discharge from the methadone maintenance program was the most common reason--73% (8/11). Thus, among the 31 subjects who were not discharged from methadone maintenance, 90% (28/31) successfully completed INH prophylaxis. The median duration of therapy was 182 days. CONCLUSIONS: Tuberculosis chemoprophylaxis using a liquid isoniazid-methadone admixture appears to be an effective approach to enhancing compliance with this therapy in methadone-maintained drug users.

Antitubercular Agents↗
PubMed1999

Sequence analysis and expression of a mRNA for a larval-specific cuticular protein, LCP1, from Helicoverpa armigera.

Several cDNA clones for a larval cuticular protein from Helicoverpa armigera were isolated and sequenced. The cDNA clones contain an open reading frame encoding a 109 residue protein which is homologous to other known cuticular proteins. The predicted protein appears to have a signal peptide which would be removed to give a mature protein of 91 amino acid residues with an Mr of 10 127. The mature protein, LCP1 (Larval Cuticular Protein), would be highly acidic, as is found for other cuticular proteins from flexible insect cuticles. The mRNA appears to be expressed throughout larval development although it is more highly expressed in the integument of the late final instar.

Amino Acid Sequence↗
PubMed1999

Cortical activation during human volitional swallowing: an event-related fMRI study.

Functional magnetic resonance imaging (fMRI) provides a safe, noninvasive method for studying task-related cortical neuronal activity. Because the cerebral cortex is strongly implicated in the control of human swallowing, we sought to identify its functional neuroanatomy using fMRI. In 10 healthy volunteers, a swallow event-related paradigm was performed by injecting 5 ml water bolus into the oral cavity every 30 s. Whole brain functional magnetic susceptibility -weighted spiral imaging data were simultaneously acquired over 600 s on a 1.5-T magnetic resonance scanner, utilizing the blood oxygenation level-dependent technique, and correlation maps were generated using both >99% percentile rank and spatial extent thresholding. We observed areas of increased signal change consistently in caudal sensorimotor cortex, anterior insula, premotor cortex, frontal operculum, anterior cingulate and prefrontal cortex, anterolateral and posterior parietal cortex, and precuneus and superiomedial temporal cortex. Less consistent activations were also seen in posterior cingulate cortex and putamen and caudate nuclei. Activations were bilateral, but almost every region, particularly the premotor, insular, and frontal opercular cortices, displayed lateralization to one or the other hemisphere. Swallow-related cortical activity is multidimensional, recruiting brain areas implicated in processing motor, sensory, and attention/affective aspects of the task.

Adult↗
PubMed1998

Microfabricated microneedles: a novel approach to transdermal drug delivery.

Although modern biotechnology has produced extremely sophisticated and potent drugs, many of these compounds cannot be effectively delivered using current drug delivery techniques (e.g., pills and injections). Transdermal delivery is an attractive alternative, but it is limited by the extremely low permeability of skin. Because the primary barrier to transport is located in the upper 10-15 micron of skin and nerves are found only in deeper tissue, we used a reactive ion etching microfabrication technique to make arrays of microneedles long enough to cross the permeability barrier but not so long that they stimulate nerves, thereby potentially causing no pain. These microneedle arrays could be easily inserted into skin without breaking and were shown to increase permeability of human skin in vitro to a model drug, calcein, by up to 4 orders of magnitude. Limited tests on human subjects indicated that microneedles were reported as painless. This paper describes the first published study on the use of microfabricated microneedles to enhance drug delivery across skin.

Administration, Cutaneous↗
PubMed1998

IgG subclass distribution of antibody responses to protein and polysaccharide mycobacterial antigens in leprosy and tuberculosis patients.

Immunoenzymatic assays were developed for the measurement of antibodies against mycobacterial lipoarabinomannan (LAM), a cell-free proteic extract (CFX) of Mycobacterium leprae, and the 38-kD protein antigen of M. tuberculosis. Sera from 108 leprosy patients, belonging to all clinical-immunological forms of the spectrum, and 81 patients with localized or disseminated tuberculosis (TB) were tested for antibodies of the four IgG subclasses. Standard calibration curves were used to allow comparisons between results of different isotypes and specificities. Mean concentrations of total IgG antibodies were higher in the overall leprosy population than in TB patients. In leprosy, levels of anti-CFX increased from tuberculoid toward lepromatous forms, with a clear switch from IgG1 to IgG2 subclass predominance. A similar IgG1 to IgG2 conversion was observed in anti-LAM antibodies, although total levels of anti-LAM were similar in patients with tuberculoid and lepromatous forms. In TB, antibodies against polysaccharide and protein antigens were both predominantly of IgG1 subclass, whatever the patient's clinical status, although lower in disseminated forms, probably due to concomitant HIV infection. A hypergammaglobulinaemia was also found in most leprosy and TB patients. In TB this was due to increased IgG1 and IgG3, especially in HIV co-infected patients. Based on the current knowledge of the influence of T cell-secreted cytokines on human immunoglobulin isotype expression, these results do not fit with a putative role of Th1 (such as found in TB and tuberculoid leprosy (TT)) and Th2 (such as found in leprosy lepromatous (LL) leprosy) environment in the isotypy of antibody responses in mycobacterial infections. Nor do variations of isotypy according to pathological conditions seem to be related to the biochemical nature of antigens, since antibodies to LAM and protein antigens had comparable evolutions of their subclass distribution. Other factors are to be investigated in order to understand better the significance and possible roles of antibodies in mycobacterial diseases.

Adolescent↗
PubMed1998

Effects of a sympathetic activation by a lower body negative pressure on glucose and lipid metabolism.

The effects of a sympathetic activation elicited by a lower body negative pressure (LBNP) (at -15 mmHg for 75 min) were assessed in 7 healthy subjects on two occasions: (i) in post-absorptive conditions, and (ii) during glucose infusion (22.2 mumol kg-1 min-1). LBNP increased plasma norepinephrine concentration and heart rate. It did not alter whole-body glucose metabolism (measured with [6,6-2H]glucose) and glycerol turnover (measured with [1,1,2,3,3-2H]glycerol). Interstitial glycerol concentrations were monitored with microdialysis in subcutaneous adipose tissue and in skeletal muscle. LBNP increased dialysate glycerol concentrations in muscle by 16% (P < 0.03) but not in adipose tissue in post-absorptive conditions, and by 37% in adipose tissue (P < 0.05) but not in muscle during glucose infusion. These results indicate that an LBNP-induced sympathetic activation (i) does not increase endogenous glucose production, and (ii) induces only a slight stimulation of lipolysis in adipose tissue during glucose infusion.

Adolescent↗
PubMed1998

Point mutations and deletion responsible for the Bombay H null and the Reunion H weak blood groups.

OBJECTIVE: Definition of the molecular basis of the Reunion and the Bombay red cell and salivary H-deficient phenotypes. METHODS: Sequence and expression of FUT1 and FUT2 genes from H-deficient individuals. Family segregation analysis of the mutations responsible for the fucosyltransferase defects of H, secretor and Lewis systems. RESULTS: The Indian red cell H null Bombay phenotype depends on a new mutation of the FUT1 gene. T725-->G changing Leu242-->Arg. Their salivary nonsecretor phenotype is secondary to a complete deletion of the FUT2 gene. The red cell H weak Reunion phenotype depends on another new mutation of FUT1, C349-->T which induces a change of His117-->Tyr. Their salivary nonsecretor phenotype is due to the known Caucasian inactivating mutation G428-->A. CONCLUSION: Single prevalent FUT1 and FUT2 point mutations and a deletion are responsible for the Indian Bombay H null and the Reunion H weak phenotypes found on Reunion island. This is in contrast with other H-deficient phenotypes where sporadic nonprevalent inactivating mutations are the rule.

ABO Blood-Group System↗
PubMed1998

[Direct diagnosis of Chlamydia trachomatis genital infections: culture or PCR?].

PCR and culturing were compared for the routine diagnosis of Chlamydia trachomatis infections. Two laboratories experienced in both techniques participated in the study, which included 513 specimens. Both techniques were performed on each specimen; the portion of the specimen used for PCR was divided in two, and each half was sent to one of the two laboratories, where the tests were run in a blinded fashion. The PCR primers used by the two laboratories matched different parts of the bacterial genome. PCR inhibitors were looked for in all specimens. Overall, PCR was more sensitive than culturing; the difference was marked for sperm and endopelvic specimens and nonsignificant for urethral and cervical specimens. False-positive PCR results were few in number; there were no consistent false-positive results when each specimen was amplified twice. PCR inhibitors were rarely present in urethral and cervical specimens but were found in 7% of sperm and endopelvic specimens. PCR inhibitors should be looked for routinely during PCR testing of sperm or endopelvic specimens.

Bacteriological Techniques↗
PubMed1997

Efficacy and safety of lamivudine on replication of recurrent hepatitis B after cadaveric renal transplantation.

BACKGROUND: The aim of this pilot study was to evaluate the efficacy and the safety of lamivudine therapy in hepatitis B virus (HBV)-positive/DNA-positive renal transplant recipients. METHODS: Six HBV DNA-positive cadaveric renal transplant recipients ranging in age from 49+/-6 years were administered lamivudine, at 100 mg/day for a period of at least 6 months, on a compassionate-use basis. Lamivudine is the (-) enantiomer of 3'-thiacytidine, which is known to be a potent inhibitor of HBV replication. All of the patients but one were on cyclosporine-based immunosuppression. RESULTS: The mean serum creatinine was 134+/-44 micromol/L. The mean duration of HBV infection was 230+/-54 months (156-288). All of the patients but one had high serum alanine aminotransferase levels (122+/-52 IU/L; range, 45-243). Histological evaluation showed the presence of either chronic active hepatitis (n=4) or cirrhosis (n=2). All of the patients but one were hepatitis B e antigen negative/hepatitis B e antibody positive, but none were coinfected with either hepatitis C virus or hepatitis D virus. CONCLUSIONS: Lamivudine therapy was associated with (i) a normalization of alanine aminotransferase levels in four of five patients when these levels were increased at the beginning (n=5); (ii) a rapid disappearance of HBV DNA from the serum (detected by hybridization) in all of the patients; (iii) the negativity of HBV DNA by polymerase chain reaction in four patients; and (iv) no change in renal function and in proteinuria when present (one patient). Finally, no adverse effects were noted. When lamivudine therapy was stopped for four patients after 6 months, it was associated with a biochemical and virological relapse within the weeks that followed. Lamivudine therapy was therefore resumed for these patients.

Antiviral Agents↗
PubMed1997

Evolution of fucosyltransferase genes in vertebrates.

Cloning and expression of chimpanzee FUT3, FUT5, and FUT6 genes confirmed the hypothesis that the gene duplications at the origin of the present human cluster of genes occurred between: (i) the great mammalian radiation 80 million years ago and (ii) the separation of man and chimpanzee 10 million years ago. The phylogeny of fucosyltransferase genes was completed by the addition of the FUT8 family of alpha(1,6)fucosyltransferase genes, which are the oldest genes of the fucosyltransferase family. By analysis of data banks, a new FUT8 alternative splice expressed in human retina was identified, which allowed mapping the human FUT8 gene to 14q23. The results suggest that the fucosyltransferase genes have evolved by successive duplications, followed by translocations, and divergent evolution from a single ancestral gene.

Amino Acid Sequence↗
PubMed1997

Morphological alterations in the peripheral and central nervous systems of mice lacking glial cell line-derived neurotrophic factor (GDNF): immunohistochemical studies.

Glial cell line-derived neurotrophic factor (GDNF) is a member of the TGF-beta superfamily of growth factors with neurotrophic activity on midbrain dopaminergic neurons and on developing and mature motoneurons of the brainstem and spinal cord. To investigate the extent of GDNF dependency of central and peripheral nervous structures during development, we have performed an immunohistochemical analysis of sections from the whole head including brain, peripheral ganglia, developing teeth and tongue, as well as intestines, in mutant mice lacking a part of the third exon that encodes the GDNF protein. As described previously, these null-mutated mice lack most of the enteric nerve plexus and are subject to agenesis or severe dysgenesis of the kidneys. In the present communication, we examined the development of vibrissae and incisor and molar teeth, as well as the innervation of these structures, and found no differences between null-mutated and control mice. A decrease in the immunohistochemical labeling intensity with tyrosine hydroxylase was observed in the superior cervical ganglion (SCG), as well as in the pontine nucleus locus coeruleus, and the sympathetic innervation of blood vessels and glands in the head was significantly decreased. None of the brain nuclei studied exhibited any significant decreases in the total number of neurons, but the packing density of neurons in the nucleus locus coeruleus was decreased. These data indicate that GDNF might be one neurotrophic factor that contributes to the development of central and peripheral noradrenergic neurons.

Animals↗
PubMed1997

Glial cell line-derived neurotrophic factor improves survival of ventral mesencephalic grafts to the 6-hydroxydopamine lesioned striatum.

One approach to replace lost dopaminergic neurons in Parkinson's disease is to transplant fetal mesencephalic tissue into the striatum. In an attempt to expand the developmental window useful for grafting of mesencephalic tissue and increase the fiber outgrowth from grafted dopaminergic neurons, we have pretreated fetal mesencephalic tissue with the dopaminotrophic factor glial cell line-derived neurotrophic factor (GDNF). Mesencephalic tissue pieces from embryonic day 18-19 Fischer 344 rats were preincubated for 20 min with GDNF (1 microg/microl) or vehicle. Two tissue pieces were then transplanted into the striatum of rats that had been unilaterally lesioned by medial forebrain bundle injections of 6-hydroxydopamine. The animals were tested for apomorphine-induced rotations prior to intracranial grafting. Host rats received intrastriatal injections of 10 microg GDNF or control solution at 10 days and 4 weeks postgrafting. The animals were tested in the rotometer twice monthly following transplantation. Despite the fact that these transplants were from a suboptimal donor stage, the rotations were significantly decreased in both transplanted groups. Immunohistochemical evaluation of the host brains revealed that the overall size of transplanted mesencephalic tissue was significantly increased in the GDNF-treated animals, and that the average size of transplanted tyrosine hydroxylase (TH)-positive neurons was also increased. Furthermore, we found that the innervation density of surrounding host striatal tissue was significantly increased in the GDNF-treated group, as compared with controls. Taken together, these results suggest that treatment of intrastriatal ventral mesencephalon grafts with GDNF can optimize the conditions for intracranial grafting and thus improve the chances for functional recovery following the intrastriatal grafting procedure.

Animals↗