Search PubMed⌕ Search

Biomedical subjects

M Montes

Publications and source records attributed to M Montes.

At least 73 records · Page 4Linked to original sources
PubMed1998

Laser in situ keratomileusis for simple myopic, mixed, and simple hyperopic astigmatism.

PURPOSE: To summarize initial results of astigmatic laser in situ keratomileusis (LASIK) for 41 eyes of 26 patients using the EC-5000 Nidek system and assess its safety, efficacy and predictability. METHODS: The EC-5000 Nidek excimer laser was used to correct simple myopic, mixed, and simple hyperopic astigmatism with manifest cylinder from 2.00 to 6.50 D. Ablation zone diameters were 6.5 mm (steep meridian ablation) to 7.5 mm (flat meridian ablation) with a repetition rate of 40-41 Hz. In eyes with simple myopic and mixed astigmatism, ablation was performed in both meridians; in eyes with simple hyperopic astigmatism, ablation was performed in the flat meridian alone. Follow-up was 3 months in all eyes. RESULTS: Uncorrected visual acuity was 20/40 or better in 85% of the eyes. Uncorrected visual acuity was equal to the preoperative spectacle-corrected visual acuity in 63% of the eyes. Intended cylinder correction was within 1.00 D in 95% of eyes. No eyes lost lines of spectacle-corrected visual acuity. CONCLUSION: LASIK using the EC-5000 excimer laser appears to effective in the treatment of simple myopic, mixed, and simple hyperopic astigmatism, with favorable results as compared to those previously described for astigmatic keratotomy.

Astigmatism↗
PubMed1998

Facial nerve stimulation from cochlear implants.

OBJECTIVE: To evaluate the incidence of facial nerve stimulation from cochlear implants and to better define the segment of nerve being stimulated and the causes of stimulation. STUDY DESIGN: Retrospective patient case review and a temporal bone dissection study. SETTING: A tertiary care setting. PATIENTS: All patients given a cochlear implant at the Hospital of the University of Pennsylvania. This encompassed only adult patients. INTERVENTION: All patients had surgical insertion of either a 3M single channel, Nucleus 22-channel, or CLARION multichannel cochlear implant. MAIN OUTCOME MEASURES: Demonstration of facial nerve stimulation with a cochlear implant and determination of affected electrodes; measurement of electrode location and distances between the labyrinthine segment of the facial nerve and the cochlea in temporal bone dissections: and determination of the relationship between the labyrinthine facial nerve and the cochlea using computed tomography evaluation. RESULTS: The overall incidence of facial nerve stimulation using all three devices was 14% (8 of 58). Otosclerosis and otosyphilis appear to be predisposing conditions to stimulation. The mid-cochlear electrodes, located near the labyrinthine facial nerve, appear to cause stimulation of the VIIth nerve most commonly. Computed tomographic evaluation of the bone between the labyrinthine fallopian canal and the cochlea may provide some indication of potential facial nerve problems. CONCLUSION: Facial nerve stimulation from the use of cochlear implants is more prevalent in patients with otosclerosis and otosyphilis. The labyrinthine segment of the facial nerve is the most likely area being stimulated in most patients. Preoperative computed tomographic evaluation may be beneficial in determining the possibility of this problem.

Adult↗
PubMed1997

HIV coreceptor downregulation as antiviral principle: SDF-1alpha-dependent internalization of the chemokine receptor CXCR4 contributes to inhibition of HIV replication.

Ligation of CCR5 by the CC chemokines RANTES, MIP-1alpha or MIP-1beta, and of CXCR4 by the CXC chemokine SDF-1alpha, profoundly inhibits the replication of HIV strains that use these coreceptors for entry into CD4(+) T lymphocytes. The mechanism of entry inhibition is not known. We found a rapid and extensive downregulation of CXCR4 by SDF-1alpha and of CCR5 by RANTES or the antagonist RANTES(9-68). Confocal laser scanning microscopy showed that CCR5 and CXCR4, after binding to their ligands, are internalized into vesicles that qualify as early endosomes as indicated by colocalization with transferrin receptors. Internalization was not affected by treatment with Bordetella pertussis toxin, showing that it is independent of signaling via Gi-proteins. Removal of SDF-1alpha led to rapid, but incomplete surface reexpression of CXCR4, a process that was not inhibited by cycloheximide, suggesting that the coreceptor is recycling from the internalization pool. Deletion of the COOH-terminal, cytoplasmic domain of CXCR4 did not affect HIV entry, but prevented SDF-1alpha-induced receptor downregulation and decreased the potency of SDF-1alpha as inhibitor of HIV replication. Our results indicate that the ability of the coreceptor to internalize is not required for HIV entry, but contributes to the HIV suppressive effect of CXC and CC chemokines.

Animals↗
PubMed1996

Prevalence and significance of implantation site trophoblastic atypia in hydatidiform moles and spontaneous abortions.

The authors studied the prevalence and significance of implantation site trophoblastic atypia in hydatidiform moles and spontaneous abortions. Three pathologists independently categorized 99 early abortion specimens regarding diagnosis (spontaneous abortion, partial hydatidiform mole, complete hydatidiform mole); qualitative atypia of implantation site trophoblast (absent, mild, moderate-severe); and quantitative atypia of implantation site trophoblast (absent, focal, diffuse). Interobserver agreement was good to excellent regarding diagnosis (kappa 0.66-0.79) and poor to fair regarding qualitative atypia of implantation site trophoblast (kappa 0.20-0.43). By consensus diagnosis, implantation site trophoblastic atypia was mild and focal in 5% of 22 spontaneous abortions; predominantly focal in 40% of 30 partial moles (33% mild atypia; 7% moderate-severe atypia); and, predominantly diffuse in 87% of 47 complete moles (21% mild atypia; 66% moderate-severe atypia). Among hydatidiform moles, the subsequent development of persistent gestational trophoblastic tumor did not relate to the degree of implantation site trophoblastic atypia. The authors conclude that trophoblast of the implantation site exhibits focal, mild atypia in some partial hydatidiform moles,and diffuse marked atypia in most complete hydatidiform moles. Thus, implantation site trophoblastic atypia may be a useful pathologic guideline regarding the diagnosis and classification of hydatidiform moles.

Abortion, Spontaneous↗
PubMed1995

Non-endoscopic method to obtain Helicobacter pylori for culture.

A sampling method to collect samples for Helicobacter pylori culture that is easier than endoscopy would be useful. We used a capsule attached to a highly absorbent nylon string, which is swallowed to obtain gastric secretions. Antral biopsy and string specimens, sequentially obtained from 36 adults with clinically suspected ulcer or gastric disease were cultured. 9 (25%) patients were negative in both tests; 18 (50%) were positive by both methods; 6 (17%) were biopsy positive and string-test negative; and 3 (8%) were biopsy negative and string-test positive. The new test is useful, simple, and causes little discomfort.

Adult↗
PubMed1995

Coxiella burnetii infection in subjects with HIV infection and HIV infection in patients with Q fever.

The objective of the study was to determine whether HIV infection favors the acquisition of Coxiella burnetii infection or increases the frequency of symptomatic Coxiella infections. A total of 754 subjects were tested for Coxiella antibodies: 596 intravenous drug users (IVDUs) (306 HIV-infected IVDUs matched by aged and sex with 291 non-HIV-infected IVDUs), and 157 healthy puerperal women matched to the IVDU women. A total of 520 patients with Q fever were tested for HIV antibodies. The seroprevalence of Coxiella antibodies was similar in the 2 groups of IVDUs (19.3% of HIV + IVDUs vs 22.9% of HIV - IVDUs). Likewise, there was no difference in the prevalence of Coxiella antibodies in the groups of IVDU women and healthy women. Of the 520 subjects with acute Q fever, diagnosed between 1987 and 1992, only 4 (0.77%) had HIV infection. The proportions of HIV-infected subjects in the population of patients, with Q fever, of 20-39 years of age (the age of maximum incidence of both HIV and Coxiella infection in our region), coincided with the estimated proportions of HIV subjects in the respective general populations of the province. In conclusion, infection by Coxiella burnetii was not more frequent among HIV-infected subjects. It is not likely that Coxiella infection produces symptomatic infections more often in HIV-infected subjects.

Adolescent↗
PubMed1994

[Immunity against tetanus in adults over the age of 49 years].

BACKGROUND: Despite the existence of an effective, cheap vaccine with few side effects, tetanus remains present in Spain with most of the cases being observed in subjects over the age of 49 years. The present seroepidemiologic study was performed to detect the degree of protection of this population. METHODS: The presence of antitetanic antibodies were determined in 324 subjects over the age of 49 (range: 50-88 years, mean 65.5 +/- 9.8 years) in Guipúzcoa. A passive hemagglutination technique (Tetan test; Istituto Sieroterápico Milanese) was used to detect tetanic antitoxoid antibodies following validation of the technique with a neutralizing test of the toxin in white mouse. RESULTS: Only 12.3% (40/324) of the subjects were considered as immune versus tetanus. The older subjects were the least protected: 7.7% (8/104) of those over 70 years of age versus 17.3% (17/98) of those from 50-59 years of age (chi 2 = 4.34, p = 0.037). The women were globally less protected: 5.4% versus 17% (33/194) males (chi 2 = 9.72; p = 0.002). CONCLUSIONS: Most of the adult population over the age of 49 years in Guipúzcoa is not protected against tetanus. This is in contrast with the situation observed in the infant and adolescent population. Specific preventive measures directed at the adult and elderly population should be undertaken.

Age Factors↗
PubMed1994

Meconium analysis to assess fetal exposure to nicotine by active and passive maternal smoking.

We measured nicotine metabolites (cotinine and trans-3'-hydroxycotinine) in meconium of infants of passive or active smokers as a direct marker of fetal exposure to tobacco smoke. Meconium was collected from 55 infants whose mothers were nonsmokers, passive smokers, or light or heavy active smokers. Nicotine metabolite concentration (NMC) in meconium was analyzed by radioimmunoassay and gas chromatography-mass spectrometry. Radioimmunoassay showed the following mean meconium NMCs (in nanograms per milliliter); nonsmoker, 10.9; passive smoker, 31.6; light active smoker; 34.7, and heavy active smoker, 54.6. Analysis of available samples by gas chromatography-mass spectrometry confirmed the presence of cotinine. Correlation between meconium NMC and the degree of maternal smoking was 0.54 (p < 0.001). Meconium NMCs in infants of passive and active smokers were significantly higher than in those of nonsmokers (p < 0.05). Meconium NMC in passive smokers was not significantly different from that in light active smokers (p > 0.05). Thus exposure of the fetus to tobacco smoke is substantial, even by passive maternal smoking. Meconium analysis for nicotine metabolites may be useful for clinical and research purposes.

Cotinine↗