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Biomedical subjects

V Martinez

Publications and source records attributed to V Martinez.

At least 37 records · Page 2Linked to original sources

[Current antiretroviral therapy].

INTRODUCTION: Advances in HIV/AIDS therapy have been rapid and profound. CURRENT KNOWLEDGE AND KEY POINTS: In developed countries the epidemic infection has stabilized and there are dramatic decreases in morbidity and mortality resulting from the use of intensive but expensive therapies. HIV patients who have detectable viral loads and/or evidence of immunologic dysfunction should be treated with a potent combination antiretroviral regimen. Currently, this consists of two nucleoside reverse transcriptase inhibitors with at least one protease inhibitor, or a non-nucleoside reverse transcriptase inhibitor, or another combination with adequate potency. Current therapies do have limitations, including side effects, cross-resistance, adherence challenges, and drug interactions. FUTURE PROSPECTS AND PROJECTS: Drug resistance is a major factor contributing to the failure of antiretroviral therapy: the ability to predict clinical response to therapy on the basis of genotype and/or phenotype depends on knowledge of appropriate data for defining drug resistance. Moreover, careful selection and monitoring of combination drug therapy along with individualized rather than standard dosage regimens may minimize the pharmacological problems and help ensure optimum antiviral activity. Further developments include new drugs, vaccine, cytokine-, and gene therapy-based treatment strategies.

Anti-HIV Agents↗

Unilateral polymicrogyria: a common cause of hemiplegia of prenatal origin.

We describe a series of 13 patients, ten males and three females, with ages ranging between three and fourteen years, who show unilateral polymicrogyria (in the left cerebral hemisphere in four cases and in the right in nine). The first and the main clinical alteration in all 13 cases was hemiparesis that did not change along the years. Ten patients had seizures that were completely controlled in seven. Three cases never presented seizures. Spontaneous threat of abortion or arterial hypertension during the first five months of pregnancy occurred in five cases. Weight less than 3 kg at birth was observed in six cases. The only patient who shows severe mental retardation associated with deafness is a girl who had infantile spasms at 20 days of age and presents duplication of a short arm of the chromosome X. Conventional magnetic resonance (MR) studies, performed in four cases did not disclose polymicrogyria but only an enlarged cortex that was diagnosed as cortical dysplasia. Three-dimensional MR (3DMR) images are very important not only to see the polymicrogyria, but also its extension and severity, especially if, moreover the axial, coronal and sagittal views, oblique, frontal, occipital, basal and superior images of the hemispheric cortical surface are performed.

Adolescent↗

Seasonal variation in prevalence of antibody to hantaviruses in rodents from southern Argentina.

We conducted a small mammal trapping study to investigate temporal variation in prevalence of infection in hantavirus reservoir populations in the Patagonian Andes mountain range, Rio Negro province, Argentina. Rodent blood samples collected in natural and periurban habitats and at the home of an hantavirus pulmonary syndrome (HPS) case patient were analysed by enzyme-linked immunosorbent assay. Organ tissue samples were tested by polymerase chain reaction (PCR) and nucleotide sequence analysis. Eight species of 1032 rodents were captured in 15 551 trap nights, giving an overall trap success of 6.6%. Hantavirus antibody was detected in 30 of 555 Oligoryzomys longicaudatus (reservoir of Andes virus), three of 411 Abrothrix longipilis, and one of 10 Loxodontomys micropus. Antibody prevalences in O. longicaudatus were 13.7% in spring 1996, 59.3% in summer 1996, 2.1% in autumn 1997, 12.4% in winter 1997 and 3.1% in spring 1997. A much higher antibody prevalence (33%) was found during trapping around the residence of an HPS case patient. Higher prevalences were found in older male O. longicaudatus. There was no apparent correlation of antibody prevalence with rodent population density, or of rodent population density or antibody prevalence with numbers of human cases. For an HPS case that occurred in our study area in 1997, we identified the probable rodent reservoir and likely site of exposure by matching the genetic sequences of virus obtained from a rodent and the HPS case patient.

Animals↗

Surgical resection for intractable epilepsy in "double cortex" syndrome yields inadequate results.

PURPOSE: To analyze the results of surgical treatment of intractable epilepsy in patients with subcortical band heterotopia, or double cortex syndrome, a diffuse neuronal migration disorder. METHODS: We studied eight patients (five women) with double cortex syndrome and intractable epilepsy. All had a comprehensive presurgical evaluation including prolonged video-EEG recordings and magnetic resonance imaging (MRI). RESULTS: All patients had partial seizures, with secondary generalization in six of them. Neurologic examination was normal in all. Three were of normal intelligence, and five were mildly retarded. Six patients underwent invasive EEG recordings, three of them with subdural grids and three with stereotactic implanted depth electrodes (SEEG). Although EEG recordings showed multilobar epileptic abnormalities in most patients, regional or focal seizure onset was recorded in all. MRI showed bilateral subcortical band heterotopia, asymmetric in thickness in three. An additional area of cortical thickening in the left frontal lobe was found in one patient. Surgical procedures included multiple subpial transections in two patients, frontal lesionectomy in one, temporal lobectomy with amygdalohippocampectomy in five, and an additional anterior callosotomy in one. Five patients had no significant improvement, two had some improvement, and one was greatly improved. CONCLUSION: Our results do not support focal surgical removal of epileptogenic tissue in patients with double cortex syndrome, even in the presence of a relatively localized epileptogenic area.

Adolescent↗

The role of vitreoretinal surgery in the management of myopic macular hole without retinal detachment.

PURPOSE: To evaluate the anatomic and functional outcome of vitreoretinal surgery in eyes with pathologic myopia and macular hole and to determine if surgery improves visual acuity. METHODS: Twenty-four consecutive highly myopic eyes with full-thickness macular hole without posterior retinal detachment were treated by vitrectomy. Posterior hyaloid dissection, removal of epiretinal and internal limiting membranes (ILM) if thickened, instillation of platelet concentrate, and flushing with 25% sulfur hexafluoride were performed. RESULTS: Patients' refractive error ranged between -8.0 and -17.5 diopters, and axial length ranged from 27.1 to 31.4 mm. Two epimacular membranes and 10 macular ILM were removed. Ten patients also underwent phacoemulsification and intraocular lens implantation at the same procedure. Mean preoperative best-corrected visual acuity was 20/200. Successful anatomic macular hole closure occurred 6 months postoperatively in 100% of eyes after one (21 eyes, 87.5%) or two surgeries (3 eyes, 12.5%). Visual acuity improved three or more lines in 83.3% of patients. Mean postoperative visual acuity was 20/70. No retinal detachment was observed during the follow-up period, which ranged from 12 to 45 months. CONCLUSION: Our results suggest that vitreoretinal surgery may effectively manage myopic macular holes, thus improving anatomic and visual outcomes. By closing the hole, vitreoretinal surgery may decrease the risk of posterior retinal detachment in highly myopic eyes.

Adult↗

Vitreoretinal surgery and endoresection in high posterior choroidal melanomas.

PURPOSE: Eyes with posterior choroidal melanomas more than 9 mm in thickness frequently are enucleated because of the potential complications of radiotherapy. The aim of this study was to evaluate the safety and efficacy of internal resection of these tumors. METHODS: Twenty-five consecutive patients with high posterior choroidal melanomas with a diameter less than 15 mm and a thickness greater than 9 mm were treated. If the retina was not invaded by the tumor, a vitrectomy was performed, followed by posterior hyaloid dissection, 120 degrees anterior retinotomy, endophotocoagulation 2 mm past the tumor margin, melanoma removal with the vitrectomy probe, retinal reattachment with liquid perfluorocarbon and air, and silicone oil exchange. If the tumor invaded the retina, the laser was applied through the retina, and the retina and tumor were removed together. RESULTS: The mean patient age was 46.6 years. The tumor thicknesses ranged from 9.1 to 12.8 mm, and the tumor diameter ranged from 8.9 to 14.8 mm. The mean preoperative visual acuity was 20/60. In 11 patients, the tumor had invaded the retina. We removed the entire tumor from all 25 eyes. The main postoperative complications were cataract (40%), retinal detachment (16%), macular traction (16%), and epiretinal macular proliferation (8%). The mean postoperative visual acuity was 20/100. No tumors recurred, and there was no evidence of metastasis. The follow-up ranged from 12 to 72 months. CONCLUSIONS: These data suggest that internal resection of high posterior melanomas may conserve ocular and functional vision and does not seem to increase the risk of metastatic disease. Longer follow-up is necessary to establish the safety of the procedure.

Adult↗

The expression of ccn3 (nov) RNA and protein in the rat central nervous system is developmentally regulated.

AIMS: To establish the expression pattern of ccn3 (nov) in the central nervous system (CNS) of adult rats and to determine whether spatiotemporal variations in the expression of ccn3 (nov) are related to specific developmental stages and/or specific CNS functions. METHODS: The sites of ccn3 (nov) expression have been identified by in situ hybridisation using didoxigenin labelled cRNA and by the reverse transcription-polymerase chain reaction (RT-PCR). The rat CCN3 (NOV) protein was characterised by western blotting performed on brain extracts. The localisation of the CCN3 (NOV) protein in the brain was established by immunocytochemistry. RESULTS: Increased expression of ccn3 (nov) was detected in the developing brain of rats after birth, as shown by RT-PCR and immunocytochemistry analysis performed on a series of samples taken between day 5 (P5) and day 300 (P300), with a pronounced peak between P15 and P150, suggesting that CCN3 (NOV) might play a role in the maintenance or establishment of specific brain functions. The relatively high amounts of an N-terminal truncated CCN3 (NOV) related protein detected both in the brain tissues and cerebrospinal fluid suggested that post translational processing of CCN3 (NOV) might be particularly prevalent in the brain. Such processing might be of biological importance in the light of the previously reported growth stimulatory effects of N-terminal truncated CCN3 (NOV) isoforms. CONCLUSIONS: The postnatal differential expression of ccn3 (nov) in the brain of developing rats suggests that CCN3 (NOV) might be involved in the acquisition of specific functions. The rat species provides an as yet unequalled system for these studies. Because the CCN3 (NOV) protein is detected in restricted areas of the brain, it will be interesting to establish whether variations of ccn3 (nov) expression are associated with normal cognitive processes and whether ccn3 (nov) expression is affected by aging. In addition, because CCN3 (NOV) is found in the spinal cord and along the axonal processes, it will be of interest to determine the expression of the normal and truncated isoforms of CCN3 (NOV) in various pathological conditions, such as neurodegenerative diseases.

Animals↗

Stress and the gastrointestinal tract III. Stress-related alterations of gut motor function: role of brain corticotropin-releasing factor receptors.

Alterations of gastrointestinal (GI) motor function are part of the visceral responses to stress. Inhibition of gastric emptying and stimulation of colonic motor function are the commonly encountered patterns induced by various stressors. Activation of brain corticotropin-releasing factor (CRF) receptors mediates stress-related inhibition of upper GI and stimulation of lower GI motor function through interaction with different CRF receptor subtypes. CRF subtype 1 receptors are involved in the colonic and anxiogenic responses to stress and may have clinical relevance in the comorbidity of anxiety/depression and irritable bowel syndrome.

Animals↗

Rothia dentocariosa endocarditis complicated by multiple intracranial hemorrhages.

Rothia dentocariosa is a gram-positive rod found commonly as part of the normal flora of the mouth. It rarely causes clinical disease. Subacute infective endocarditis has been the most commonly reported R dentocariosa infection, and extracardiac complications occur frequently. Solitary intracranial hemorrhages have been reported in two cases. We describe the first case of infective endocarditis complicated by the sequential and unusually prolonged development of multiple new intracranial hemorrhages.

Actinomyces↗

[Metronidazole].

Metronidazole was first introduced for the treatment of trichomoniasis. Now, its therapeutics use has subsequently been expanded to include protozoal and anaerobic infections. Oral administration is recommended: rosacea, perioral dermatitis, Helicobacter pylori, Trichomonas vaginalis and Giardia lamblia infections and bacterial vaginosis. Metronidazole given orally is absorbed almost completely. Metronidazole has limited plasma protein binding but can reach very favourable tissue distribution, including central nervous system and placenta. This drug is extensively metabolised by the liver to form 5 oxydative metabolites. The majority of this drug and metabolites are excreted in urine and feces. The half-life is 6 to 10 hours. The recommended dose is 500 mg three time per day and an adaptation is necessary in renal insufficiency. Metronidazole is well tolerated when administered in dosages of less than 2 g per day. Some adverse reactions appear to be related to the high dosages and treatment duration. Drug interactions with alcohol, warfarin and phenytoin have been reported. Mutagenesis and cancerogenesis is only described in mouse. Resistance, both clinical and microbiological, has been described only rarely.

Anti-Infective Agents↗

Differential Fos expression in the paraventricular nucleus of the hypothalamus, sacral parasympathetic nucleus and colonic motor response to water avoidance stress in Fischer and Lewis rats.

The responsiveness of hypothalamic CRF to various stressors is reduced in the young female Lewis relative to the histocompatible Fischer rat. Whether such a difference impacts the brain-gut response to water avoidance stress was investigated by monitoring Fos immunoreactivity in the brain and sacral spinal cord and fecal pellet output. Exposure for 60 min to water avoidance stress increased the number of Fos positive cells in the paraventricular nucleus of the hypothalamus (PVN), nucleus tractus solitarius (NTS), and the parasympathetic nucleus of the lumbo-sacral spinal cord (L6-S1) in both Lewis and Fischer rats compared with non stress groups. The Fos response was lower by 32.0% in the PVN, and 63% in sacral parasympathetic nucleus in Lewis compared with Fischer rats while similar Fos expression was observed in the NTS. Stress-induced defecation was reduced by 52% in Lewis compared with Fischer rats while colonic motor response to CRF injected intracisternally resulted in a similar pattern and magnitude of defecation in both strains. The CRF receptor antagonist [D-Phe12,Nle(21,38)C(a)MeLeu(37)]-CRF(12-41) injected intracisternally antagonized partly the defecation response in Lewis and Fischer rats. These data indicate that a lower activation of PVN and sacral parasympathetic nuclei in Lewis compared with Fisher rats may contribute to the differential colonic motor response and that the blunted CRF hypothalamic response to stress, unlike responsiveness to central CRF plays a role.

Age Factors↗

Bombesin and the brain-gut axis.

Bombesin is the first peptide shown to act in the brain to influence gastric function and the most potent peptide to inhibit acid secretion when injected into the cerebrospinal fluid (CSF) in rats and dogs. Bombesin responsive sites include specific hypothalamic nuclei (paraventricular nucleus, preoptic area and anterior hypothalamus), the dorsal vagal complex as well as spinal sites at T9-T10. The antisecretory effect of central bombesin encompasses a variety of endocrine/paracrine (gastrin, histamine) or neuronal stimulants. Bombesin into the CSF induces an integrated gastric response (increase in bicarbonate, and mucus, inhibition of acid, pepsin, vagally mediated contractions) enhancing the resistance of the mucosa to injury through autonomic pathways. The physiological significance of central action of bombesin on gastric function is still to be unraveled.

Animals↗

Generalized nerve sheath tumors in neurofibromatosis type 1 (NF1). A case report.

We describe a case of chronic distal sensorimotor neuropathy associated with neurofibromatosis type 1 (NF1) in a 15-year old girl. The patient showed a striking clinical picture consisting of diffuse nodular enlargements of peripheral nerves. Motor conduction velocities were decreased and sensory responses were absent after maximal stimulation. Magnetic resonance imaging (MRI) was performed throughout the body and disclosed generalized nerve sheath neurofibromas affecting all peripheral nerves. Intracranially, the patient had a glioma of the left optic nerve, but no other cranial nerve involvement. These results demonstrate the value of MRI for visualization of the peripheral nervous system in neurofibromatosis.

Child, Preschool↗

Recombinant human insulin-like growth factor I has significant anabolic effects in adults with growth hormone receptor deficiency: studies on protein, glucose, and lipid metabolism.

The physiological effects of insulin-like growth factor I (IGF-I) on intermediate metabolism of substrates have been extensively studied in a variety of experimental situations in man, and its effects on linear growth of children with GH receptor mutations have proven beneficial. However, there is a paucity of data on the metabolic effects of IGF-I as replacement therapy in adults with GH receptor deficiency (Laron's syndrome). We designed these studies to investigate the in vivo effects of 8 weeks of therapy with recombinant human IGF-I (rhIGF-I) in a unique group of 10 adult subjects with profound IGF-I deficiency due to a mutation in the GH receptor gene (mean +/- SEM age, 29.2 +/- 2.0 yr; 4 males and 6 females). At baseline, patients had infusions of stable tracers, including L-[13C]leucine, [2H2]glucose, and d5-glycerol, as well as indirect calorimetry, assessment of body composition (dual energy x-ray absortiometry), and measurements of growth factor concentrations. Patients were then discharged to receive twice daily rhIGF-I (60 microg/kg, sc) for the next 8 weeks when the studies were repeated identically. Plasma IGF-I concentrations increased during rhIGF-I treatment from 9.3 +/- 1.5 microg/L to 153 +/- 23 (P = 0.0001). There was no change in weight during these studies, but a significant change in body composition was observed, with a decrease in percent fat mass (P = 0.003) and an increase in lean body mass (P = 0.001). These were accompanied by increased rates of protein turnover, decreased protein oxidation, and increased rates of whole body protein synthesis, as measured by leucine tracer methods (P < 0.01). These results are similar to those observed in GH-deficient subjects treated with GH. All measures of lipolytic activity and fat oxidation increased during treatment, with an 18% increase in the glycerol turnover rate (P = 0.04), an increase in free fatty acid and beta-hydroxybutyrate concentrations, and a significant increase in fat oxidation, as measured by indirect calorimetry (P = 0.04). There were significant decreases in insulin concentrations (P = 0.01) and a reciprocal increase in glucose production rates (P = 0.04) during rhIGF-I, yet plasma glucose concentrations remained constant, suggestive of a significant insulin-like action of this peptide. RhIGF-I was well tolerated by all patients. In conclusion, 8 weeks of treatment with rhIGF-I had significant positive effects on body composition and measures of intermediate metabolism independent of GH. These results suggest that, similar to GH treatment of adults with GH deficiency, rhIGF-I may be beneficial as long term replacement therapy for the adult patient with Laron's syndrome.

Adolescent↗

An initial investigation of validation of the Matrix Analogies Test-Expanded Form in Ecuador.

This is a first preliminary study of the validity and reliability of the Matrix Analogies Test--Expanded Form in South America. Participants were 104 Spanish-speaking children between the ages of 5 and 17 years living in Ecuador. Values of Cronbach alpha ranged from .87 to .92 for the 4 groups of items and was .95 for the total score. Raw scores on the MAT increased across ages. Scores of boys did not differ significantly from those of girls. Total test scores correlated significantly with scores on the Raven Standard Progressive Matrices (r = .62, p < .005; r = .82 before controlling for age). A principal factor analysis conducted to provide evidence of the test's construct validity indicated that all four sets of items loaded substantially on one unrotated factor, presumed to be g. In sum, these results suggest that the test is a valid and reliable nonverbal measure of general cognitive ability in this population.

Adolescent↗

[Cutaneous vasculitis disclosing pulmonary tuberculosis].

We report the case of a patient with leukocytoclasic vasculitis that disclosed active pulmonary tuberculosis. This patient had no signs of systemic vasculitis. The clinical course was favorable with anti-tuberculosis drugs alone. There has been no recurrence at 8 months. Vasculitis associated with tuberculosis is uncommon. The pathophysiological mechanism remains uncertain. No immunosuppressor treatment is needed and the vasculitis generally regresses with treatment of the infection.

Humans↗