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Biomedical subjects

L Martin

Publications and source records attributed to L Martin.

At least 73 records · Page 4Linked to original sources
PubMed2002

[Orofacial herpes and other localizations (genital herpes and neonatal herpes excluded)].

BACKGROUND: Herpes is a pandemic infection in the human species. The purpose of this work was to conduct a critical analysis of the literature devoted to the pathophysiology and treatment of orofacial herpes an other localizations (genital herpes and neonatal herpes excluded). METHODS: We searched for articles in English and French devoted to orofacial herpes and other herpetic localizations indexed in Medline (1980-July 001), EmBase, and the Cochrane Library (1995-July 2001). Critical analysis was based on level of proof using the ANAES methodology. RESULTS: More than 700 articles were identified. One hundred four were selected for this report. Primary HSV1 infection usually occurred before adulthood and involved acute gingivo-stomatitis in the majority of the cases. Several primary HIV1 infections were asymptomatic or aspecific and non-recognized. After the primary infection, the virus remains in the ganglion of the trigeminal nerve in a latent state and can be reactivated sporadically. Reactivation is associated with viral excretion and can be symptomatic (herpetic recrudescence) or not (recurrence). Recrudescence of orofacial herpes is typically labial. No currently available vaccine can prevent acquisition of HSV1. Treatment of acute gingivostomatitis has been standardized and is based on aciclovir. Inversely, the effectiveness of aciclovir and other nucleoside analogs with anti-herpes activity has not been clearly established for prevention or cure of recrudescence of orofacial herpes. Other localizations (hand, anus, diffuse skin localizations in contact sports, Kaposi-Juliusberg syndrome) are much more exceptional. Treatment has not been standardized. DISCUSSION: Despite the abundance of the literature on orofacial herpes, consistent quality is lacking, particularly concerning therapeutic studies. The quality of these reports is generally inferior to those devoted to genital herpes. There has however been a general trend towards improved methodology over the last years. Very little has been reported on exceptional localizations of orofacial herpes.

Acyclovir↗
PubMed2002

[Digital purpura revealing septicaemical rat-bite fever].

INTRODUCTION: Infection with Streptobacillus moniliformis is an uncommon illness which can lead to death if untreated. We report the case in which initially cutaneous signs permitted diagnosis and further identification of the organism. CASE REPORT: A 42 year-old woman presented with a three-day history of acrally distributed purpuric macules on her fingers. Two days later, she was admitted for arthritis of the knees and wrists. There were two large pustules on the left elbow and the right knee. Laboratory studies showed inflammatory changes. The diagnosis of streptobacillary rat-bite fever was made after isolation of Gram-negative bacilli from a blood-culture and from cutaneous lesions. Finally identification of the organism was made by molecular biology analysis. The patient received intravenous ofloxacin and imipenem with complete resolution of arthritis and the cutaneous lesions. DISCUSSION: Streptobacillary rat-bite fever is a systemic infectious disease. It is caused by Streptobacillus moniliformis, organism found in the oropharyngeal flora of small rodents, especially rats. The illness is uncommon in urban settings. It starts by fever, followed by arthritis and rash. Septicaemical rat-bite fever may start only with cutaneous involvement such as acral purpura, like in our case. This clinical manifestation must be recognized by the dermatologist, because the illness can lead to death if untreated.

Adult↗
PubMed2001

Electrophysiological and behavioral output of the rat basal ganglia after intrastriatal infusion of d-amphetamine: lack of support for the basal ganglia model.

Dopamine, by acting upon D1 and D2 dopamine receptors located on striatonigral and striatopallidal neurons, respectively, has been postulated to inhibit output from the substantia nigra pars reticulata (SNpr) and internal pallidal segment (GPi). The inhibition of the SNpr/GPi should, in turn, disinhibit the thalamus to facilitate movement. The present study tests this prediction in intact (unlesioned) rats by attempting to correlate changes in the single unit activities of SNpr neurons with motor (i.e. behavioral) responses in the 20-30 min after infusions of d-amphetamine into the striatum. Unilateral injections of amphetamine (20 microg/microl) into either the dorsal-rostral, central, or ventral-lateral striatum failed to appreciably alter behavior and, in parallel electrophysiological studies, failed to consistently or significantly alter the activities of SNpr neurons in either chloral hydrate-anesthetized rats or awake locally anesthetized rats. However, when amphetamine was infused bilaterally into the ventral-lateral striatum (VLS; 20 microg/microl per side), a robust behavioral activation ensued (increased locomotor activity, oral movements, and sniffing) with an onset ranging from immediate to 20 min post-infusion and persisting for at least 40 min. In parallel studies, bilateral amphetamine infusions into VLS also caused changes in the firing frequency of a majority of SNpr neurons. However, the changes in firing were extremely variable and, contrary to expectation, the net population response of SNpr neurons was an increase in firing which corresponded in time with the period of peak behavioral activation. These results show that (i) bilateral but not unilateral activation of striatal dopamine receptors is needed to elicit behavioral and electrophysiological output from the basal ganglia, and (ii) motor activation is apparently not signaled by a generalized inhibition of SNpr firing, as is predicted by the basal ganglia model.

Animals↗
PubMed2001

Two-kaon correlations in central Pb+Pb collisions at 158 a GeV/c.

Two-particle interferometry of positive kaons is studied in Pb+Pb collisions at mean transverse momenta approximately 0.25 and 0.91 GeV/c. A three-dimensional analysis was applied to the lower p(T) data, while a two-dimensional analysis was used for the higher p(T) data. We find that the source-size parameters are consistent with the m(T) scaling curve observed in pion-correlation measurements in the same collisions, and that the duration time of kaon emission is consistent with zero within the experimental sensitivity.

Journal Article↗
PubMed2001

Spectrins in developing rat hippocampal cells.

We studied the spectrins in developing hippocampal tissue in vivo and in vitro to learn how they contribute to the organization of synaptic and extrasynaptic regions of the neuronal plasma membrane. beta-Spectrin, but not beta-fodrin or alpha-fodrin, increased substantially during postnatal development in the hippocampus, where it was localized in neurons but not in astrocytes. Immunoprecipitations from neonatal and adult hippocampal extracts suggest that while both beta-spectrin and beta-fodrin form heteromers with alpha-fodrin, oligomers containing all three subunits are also present. At the subcellular level, beta-fodrin and alpha-fodrin were present in the cell bodies, dendrites, and axons of pyramidal-like neurons in culture, as well as in astrocytes. beta-Spectrin, by contrast, was absent from axons but present in cell bodies and dendrites, where it was organized in a loose, membrane-associated meshwork that lacked alpha-fodrin. A similar meshwork was also apparent in pyramidal neurons in vivo. At some dendritic spines, alpha-fodrin was present in the necks but not in the heads, whereas beta-spectrin was present at significant levels in the spine heads. The presence of significant amounts of beta-spectrin without an accompanying alpha-fodrin subunit was confirmed by immunoprecipitations from extracts of adult hippocampus. Our results suggest that the spectrins in hippocampal neurons can assemble to form different membrane-associated structures in distinct membrane domains, including those at synapses.

Age Factors↗
PubMed2001

Structural and functional analysis of the RANTES-glycosaminoglycans interactions.

Chemokines mediate their biological activity through activation of G protein coupled receptors, but most chemokines, including RANTES, are also able to bind glycosaminoglycans (GAGs). Here, we have investigated, by site-directed mutagenesis and chemical acetylation, the role of RANTES basic residues in the interaction with GAGs using surface plasmon resonance kinetic analysis. Our results indicate that (i) RANTES exhibited selectivity in GAGs binding with highest affinity (K(d) = 32.1 nM) for heparin, (ii) RANTES uses the side chains of residues R44, K45, and R47 for heparin binding, and blocking these residues in combination abolished heparin binding. The biological relevance of RANTES-GAGs interaction was investigated in CHO-K1 cells expressing CCR5, CCR1, or CCR3 and the various GAGs that bind RANTES. Our results indicate that the heparin binding site, defined as the 40s loop, is only marginally involved in CCR5 binding and activation, but largely overlaps the CCR1 and CCR3 binding and activation domain in RANTES. In addition, enzymatic removal of cell surface GAGs by glycosidases did not affect CCR5 binding and Ca(2+) response. Furthermore, addition of soluble GAGs inhibited both CCR5 binding and functional response, with a rank of potency similar to that found in surface plasmon resonance experiments. Thus, cell surface GAGs is not a prerequisite for receptor binding or signaling, but soluble GAGs can inhibit the binding and the functional response of RANTES to CCR5 expressing cells. However, the marked selectivity of RANTES for different GAGs may serve, in vivo, to control the concentration of specific chemokines in inflammatory situations and locations.

Acetylation↗
PubMed2001

Involvement of melatonin MT(3) receptors in the regulation of intraocular pressure in rabbits.

Melatonin, a neurohormone secreted by the pineal gland, can stimulate three subtypes of receptors, namely: mt(1), MT(2) and MT(3). We examined the ability of melatonin and the selective MT(3) receptor agonist, 5-methoxycarbonylamino-N-acetyltryptamine (5-MCA-NAT), to modify intraocular pressure in rabbits. Both compounds significantly reduced intraocular pressure, maximally by 24% and 43%, respectively, with IC(50) values of 363+/-23.0 and 423+/-30.0 ng/10 microl (1.6+/-0.1 and 1.8+/-0.1 nmol, respectively). The non-specific melatonin receptor antagonist, luzindole, abolished the depressant effect of both compounds, thus confirming the involvement of melatonin receptors. Our results show, for the first time, a functional response that may be regulated by melatonin MT(3) receptors, and provide evidence that supports a role of melatonin in the circadian changes of intraocular pressure.

Animals↗
PubMed2001

Involvement of apolipoprotein E in herpes simplex encephalitis.

APOE polymorphism may influence risk for cold sores and, by interacting with latent HSV-1, risk for Alzheimer's disease (AD). APOE genotype also influences outcome after brain injury. We sought to determine whether APOE genotype influences risk for herpes simplex encephalitis (HSE), whether apoE is involved in the response to HSE and if APOE genotype influences outcome from HSE. There was increased immunoreactivity of neurons, neuropil and glia for apoE areas of brain damaged by HSE. APOE genotypes for cases of HSE (n = 57) were similar to those of controls (n = 41). APOE genotypes for survivors of HSE were similar to those of patients who died. We conclude that apoE is involved in the response to damage associated with HSE, as in other forms of brain injury. However, APOE genotype does not appear to influence either the risk of developing HSE or subsequent mortality.

Adolescent↗
PubMed2001

Crystal chemistry and physical properties of superconducting and semiconducting charge transfer salts of the type (BEDT-TTF)(4)[A(I)M(III)(C2O4)3]*PhCN (A(I) = H30,NH4,K; M(III) = Cr, Fe, Co, Al; BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene.

Synthesis, structure determination by single-crystal X-ray diffraction, and physical properties are reported and compared for superconducting and semiconducting molecular charge-transfer salts with stoichiometry (BEDT-TTF)(4)[A(I)M(III)(C(2)O(4))(3)].PhCN, where A(I) = H(3)O, NH(4), K; M(III) = Cr, Fe, Co, Al; BEDT-TTF = bis(ethylenedithio) tetrathiafulvalene. Attempts to substitute M(III) with Ti, Ru, Rh, or Gd are also described. New compounds with M = Co and Al are prepared and detailed structural comparisons are made across the whole series. Compounds with A = H(3)O(+) and M = Cr, Fe are monoclinic (space group C2/c), at 150, 120 K a = 10.240(1) A, 10.232(12) A; b = 19.965(1) A, 20.04(3) A; c = 34.905(1) A, 34.97(2) A; beta = 93.69(1) degrees, 93.25(11) degrees, respectively, both with Z = 4. These salts are metallic at room temperature, becoming superconducting at 5.5(5) or 8.5(5) K, respectively. A polymorph with A = H(3)O(+) and M = Cr is orthorhombic (Pbcn) with a = 10.371(2) A, b = 19.518(3) A, c = 35.646(3) A, and Z = 4 at 150 K. When A = NH(4)(+), M = Fe, Co, Al, the compounds are also orthorhombic (Pbcn), with a = 10.370(5) A, 10.340(1) A, 10.318(7) A; b = 19.588(12) A, 19.502(1) A, 19.460(4) A; c = 35.790(8) A, 35.768(1) A, 35.808(8) A at 150 K, respectively, with Z = 4. All of the Pbcn phases are semiconducting with activation energies between 0.15 and 0.22 eV. For those compounds which are thought to contain H(3)O(+), Raman spectroscopy or C=C and C-S bond lengths of the BEDT-TTF molecules confirm the presence of H(3)O(+) rather than H(2)O. In the monoclinic compounds the BEDT-TTF molecules adopt a beta' ' packing motif while in the orthorhombic phases (BEDT-TTF)(2) dimers are surrounded by monomers. Raman spectra and bond length analysis for the latter confirm that each molecule of the dimer has a charge of +1 while the remaining donors are neutral. All of the compounds contain approximately hexagonal honeycomb layers of [AM(C(2)O(4))(3)] and PhCN, with the solvent occupying a cavity bounded by [M(C(2)O(4))(3)](3-) and A. In the monoclinic series each layer contains one enantiomeric conformation of the chiral [M(C(2)O(4))(3)](3-) anions with alternate layers having opposite chirality, whereas in the orthorhombic series the enantiomers form chains within each layer. Analysis of the supramolecular organization at the interface between the cation and anion layers shows that this difference is responsible for the two different BEDT-TTF packing motifs, as a consequence of weak H-bonding interactions between the terminal ethylene groups in the donor and the [M(C(2)O(4))(3)](3-) oxygen atoms.

Journal Article↗
PubMed2001

Evaluation of youth preferences for rapid and innovative human immunodeficiency virus antibody tests.

OBJECTIVE: To determine youth preferences for Food and Drug Administration (FDA)-approved and investigational human immunodeficiency virus (HIV) antibody collection and testing methods before and after subjects learned of test result response times; to determine how influential test result response times are on participants' preferences. DESIGN: After health educators explained and demonstrated 6 different HIV antibody collection and testing strategies (3 saliva, 1 urine, and 2 fingerstick methods), participants completed a confidential survey about test method preference and tried the different testing methods. The participants had an opportunity to re-rank their test method preference after learning about each test's result response time. SETTING: Health education sessions in both clinical and community settings. PARTICIPANTS: Youths aged 12 to 24 years. RESULTS: An oral collection device with a rapid saliva test was the most highly preferred test method. The preference for this method and the rapid response test methods via fingerstick procedures improved significantly after subjects learned of the rapid result response time, while the other methods were given significantly lower preference rankings after subjects learned of the longer result response times. Shifts in preference rankings were not related to sex, age, ethnic group, experience with HIV testing, or practice of risk behaviors. CONCLUSIONS: Our research supports the use of noninvasive and rapid HIV testing methods with rapid response times for adolescents to assist in the early identification of HIV status, while offering HIV prevention opportunities and immediate linkage to care.

Adolescent↗
PubMed2001

Differentiation potential of intestinal mesenchyme and its interaction with epithelial cells: a study using beta-galactosidase-expressing fibroblast lines.

Rat intestinal fibroblast lines (F1:G9 and A1:F1) differing in their potential to support intestinal mucosal development were marked with reporter genes to investigate their differentiation potential. The fibroblasts were transfected with plasmids expressing either beta-galactosidase (with or without a nuclear localisation signal) or green fluorescent protein (GFP). Transfection using Tfx50 or Fugene was more efficient than electroporation. The expression of beta-galactosidase was more stable and stronger than GFP. Cells were optimally labelled using the plasmid pL27B-GAL, and sub-clones with a strong and uniform nuclear expression of beta-galactosidase were isolated. These clones expressed beta-galactosidase even after prolonged passage in the absence of selection. The beta-galactosidase tagged lines (F1:G9gal and A1:F1gal) retained the morphological characteristics, viability and differentiation properties of the parental non-transfected lines. In co-culture with a colorectal tumour cell line Caco-2, the F1:G9gal and A1:F1gal cells differed in their morphological organisation but this did not change their expression of smooth muscle alpha-actin.

Animals↗
PubMed2001

Do patients with borderline personality disorder belong to the bipolar spectrum?

BACKGROUND: This report examines clinical indicators for bipolarity in a cohort of patients suffering from Borderline Personality Disorder (BPD). METHODS: The study was conducted in the Cornell-Westchester Hospital, famed for its expertise in BPD. To avoid biasing our sample, we excluded all BPD patients who were active patients in our anxiety and mood disorders program. Through the use of both open clinical interviews and standardized diagnostic interviews (SCID), borderline patients were examined for evidence of bipolarity by five indicators: history of spontaneous mania, history of spontaneous hypomania, bipolar temperaments, pharmacologic response typical of bipolar disorder, and a positive bipolar family history. RESULTS: Depending on the level of bipolar disorder from the most rigorous (mania) to the most 'soft' (bipolar family history), between 13 and 81% of borderline patients showed signs of bipolarity. Based on what the emerging literature supports as rigorously defined bipolar spectrum (bipolar I and II), we submit that at least 44% of BPD belong to this spectrum; adding hypomanic switches during antidepressant pharmacotherapy, the rate of bipolarity in BPD reaches 69%. As expected from this formulation, most responded negatively to antidepressants (e.g. hostility and agitation) and positively to mood stabilizers. LIMITATIONS: Small sample size and retrospective gathering of data on treatment response. CONCLUSION: Patients with BPD more often than not exhibit clinically ascertainable evidence for bipolarity and may benefit from known treatments for Bipolar Spectrum Disorders. Large scale, systematic treatment studies with mood stabilizers are indicated.

Adult↗