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Biomedical subjects

B Torres

Publications and source records attributed to B Torres.

At least 55 records · Page 3Linked to original sources
PubMed1992

Activities of daily functioning and community adjustment of veterans in the VA residential care program.

This study was designed to identify the level of function in Activities of Daily Living (ADL) of veterans placed in the Personal Care Home Program (PCH) of the Department of Veterans Affairs Medical Center in Puerto Rico. At the same time, we explored how community adjustment was related to the veterans ADL functioning. It was an exploratory, descriptive, cross-sectional study of a random sample of 60 veterans placed in (32) Personal Care Homes. The Functional Independence Measure (FIM) was used to evaluate the veteran and determined his level of independence in ADL. The Community Adjustment Scale was used to assess adjustment behavior patterns of veterans at the personal care homes. Findings indicate the majority of veterans in the PCH program were elderly with a mean age of 64 years. They were functioning in a modified dependence level in ADL. They had made good to excellent community adjustment. No relationship between ADL level of functioning and community adjustment was found.

Activities of Daily Living↗
PubMed1991

In vitro activity of loracarbef (LY163892), a new oral carbacephem antimicrobial agent, against respiratory isolates of Haemophilus influenzae and Moraxella catarrhalis.

The in vitro activity of a new orally administered carbacephem analog of cefaclor, loracarbef (LY163892), was compared with those of cefaclor and several other oral antimicrobial agents against recent clinical isolates of Haemophilus influenzae and Moraxella catarrhalis. Loracarbef was found to be slightly more active than cefaclor against H. influenzae and had activity essentially equivalent to that of cefaclor for M. catarrhalis. Resistance to loracarbef was uncommon and was noted only with rare beta-lactamase-producing strains of H. influenzae. On the basis of these observations, loracarbef may be of utility in the management of localized, non-life-threatening infections caused by H. influenzae and M. catarrhalis.

Anti-Bacterial Agents↗
PubMed1991

Discharge characteristics of medial rectus and abducens motoneurons in the goldfish.

1. The discharge of antidromically identified medial rectus and abducens motoneurons was recorded in restrained unanesthesized goldfish during spontaneous eye movements and in response to vestibular and optokinetic stimulation. 2. All medial rectus and abducens motoneurons exhibited a similar discharge pattern. A burst of spikes accompanied spontaneous saccades and fast phases during vestibular and optokinetic nystagmus in the ON-direction. Firing rate decreased for the same eye movements in the OFF-direction. All units showed a steady firing rate proportional to eye position beyond their recruitment threshold. 3. Motoneuronal position (ks) and velocity (rs) sensitivity for spontaneous eye movements were calculated from the slope of the rate-position and rate-velocity linear regression lines, respectively. The averaged ks and rs values of medial rectus motoneurons were higher than those of abducens motoneurons. The differences in motoneuronal sensitivity coupled with structural variations in the lateral versus the medial rectus muscle suggest that symmetric nasal and temporal eye movements are preserved by different motor unit composition. Although the abducens nucleus consists of distinct rostral and caudal subgroups, mean ks and rs values were not significantly different between the two populations. 4. Every abducens and medial rectus motoneuron fired an intense burst of spikes during its corresponding temporal or nasal activation phase of the "eye blink." This eye movement consisted of a sequential, rather than a synergic, contraction of both vertical and horizontal extraocular muscles. The eye blink could act neither as a protective reflex nor as a goal-directed eye movement because it could not be evoked in response to sensory stimuli. We propose a role for the blink in recentering eye position. 5. Motoneuronal firing rate after ON-directed saccades decreased exponentially before reaching the sustained discharge proportional to the new eye position. Time constants of the exponential decay ranged from 50 to 300 ms. Longer time constants after the saccade were associated with backward drifts of eye position and shorter time constants with onward drifts. These postsaccadic slide signals are suggested to encode the transition of eye position to the new steady level. 6. Motoneurons modulated sinusoidally in response to sinusoidal head rotation in the dark, but for a part of the cycle they went into cutoff, dependent on their eye position recruitment threshold. Eye position (kv) and velocity (rv) sensitivity during vestibular stimulation were measured at frequencies between 1/16 and 2 Hz. Motoneuronal time constants (tau v = rv/kv) decreased on the average by 25% with the frequency of vestibular stimulation.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Comparison of therapeutic regimen of anticysticercal drugs for parenchymal brain cysticercosis.

The efficacy of different regimens of therapy for parenchymal brain cysticercosis either with praziquantel (PZQ) or with albendazole (ALB) was compared in 114 patients. Four schemes of treatment were used: PZQ 50 mg/kg per day for 15 days, PZQ 50 mg/kg per day for 8 days, ALB 15 mg/kg per day for 30 days, and ALB 15 mg/kg per day for 8 days. Three months after therapy, it was apparent that both PZQ and ALB were effective, as shown by the disappearance of cystic lesions in computed tomographic scans. Thirty-three control patients followed for a mean of 11 months had no spontaneous remission of lesions. When comparing PZQ with ALB, the latter was found to be more effective than the former for both the full and the short course of treatment: 85% vs 60% and 85% vs 48% disappearance of lesions, respectively (P less than 0.001). Comparison of the full vs the short course of PZQ showed that the short course had a further 12% reduction in drug effectiveness. In contrast, the length of ALB therapy could be shortened without lessening its efficacy. Based on these results, an 8-day course of ALB is recommended as treatment for parenchymal brain cysticercosis; a 15-day course of PZQ could be subsequently used in those patients who show only partial response to ALB.

Adolescent↗
PubMed1988

Behavioral and morphological effects of oculomotor nucleus lesion on abducens internuclear neurons in the cat.

The activity of identified control and injured abducens internuclear neurons was recorded during spontaneous eye movements in the alert cat. From 2 days following the electrocoagulation of the contralateral oculomotor nucleus, abducens internuclear neurons showed a quick fatigability during eye fixations not observed in controls. Discharge rate during saccades started after the beginning of the eye movement and showed a fast exponential-like decay. These abnormal responses were not further recorded from 20 days following the lesion. Morphological studies indicated that 90% of the abducens internuclear neuron population disappeared 2 months following the lesion and showed no sign of recovery one year later.

Abducens Nerve↗
PubMed1988

Cytodifferentiation of mouse visceral endoderm: study with a teratocarcinoma antiserum.

In this work we separated homogeneous embryoid bodies (EB); this population is composed of only endodermal vesicles of a visceral type. These EB were used to immunize rabbits. After absorption, the antisera were analyzed immunohistochemically in sections of 7.5- and 9-day-old mouse embryos, which showed a selective reaction to visceral endoderm. The cytodifferentiation of the visceral endoderm was studied.

Animals↗
PubMed1987

Cysticercotic encephalitis: a severe form in young females.

Clinical and computerized tomography findings in patients with miliary infestation of cysticerci in brain parenchyma are presented. Cysticercotic encephalitis produces a severe and frequently fatal neurological disorder. Although parenchymal cysticercosis is common in endemic areas, in the cases reported here, the pathology is induced by a severe inflammatory response in brain parenchyma rather than by the physical presence of multiple cysts. As a result of diffuse brain edema, all cases develop subacute severe intracranial hypertension and compromise of visual function. One important feature of this form of neurocysticercosis is that it particularly affects young women.

Adolescent↗
PubMed1986

Analysis of the fluctuations in the interspike intervals of abducens nucleus neurons during ocular fixation in the alert cat.

The behavior of abducens nucleus motoneurons and internuclear neurons was recorded during eye fixation in the alert cat. The interspike interval (ISI) values during a given fixation followed a normal distribution, with coefficients of variation for motoneurons and interneurons ranging from 4.6 to 16% and 5.7 to 21.7%, respectively. The ISI mean was linearly related to its standard deviation and to the coefficient of variation. The power spectral density of ISI fluctuations did not reveal any relevant peak. The autocorrelation function of ISI fluctuations was flat except at the origin. Results suggest the presence of a gaussian white noise superimposed on the clock-like firing of the activity of abducens neurons during ocular fixation. Some physiological implications of the results are discussed.

Abducens Nerve↗
PubMed1986

A quantitative analysis of abducens motoneuron behavior during saccadic eye movements in the alert cat.

The activity of identified abducens motoneurons has been recorded during spontaneous eye movements in the alert cat. Abducens motoneurons showed a burst of activity during saccades in the abducting direction. However, peak frequency during the burst was reached on the 4th-7th intervals. Instantaneous frequency of the first 5 intervals during the burst was linearly related to peak saccadic velocity and to peak frequency. Functional implications of reported findings are discussed in the text. These results favor the view that firing in abducens motoneurons during saccades is predetermined from the beginning of saccades, and do not provide evidence for possible modification of abducens motoneurons firing through internal feedback of motor error signals.

Abducens Nerve↗
PubMed1986

[Neuronal activity of the external oculomotor nucleus during saccadic eye movement in the waking cat].

The activity of antidromically identified abducens nucleus motoneurons and inter-nuclear neurons has been recorded during saccadic eye movements in the alert cat. The activity of these neurons has been demonstrated to be the sum of a velocity component proportional to eye velocity plus a position component proportional to instantaneous eye position during the movement. Results are discussed in relation to proposed models about the generation of saccadic eye movements.

Abducens Nerve↗
PubMed1985

Behavioral activities of axotomized abducens nucleus motoneurons in the alert cat.

The activity of identified control and axotomized abducens motoneurons has been recorded during spontaneous eye movements in the alert cat. Axotomized motoneurons showed a quick fatigability during eye fixations not observed in controls. Discharge rate of axotomized motoneurons during on direction saccades was lower and shorter than in controls and started usually after the beginning of the saccade. Axotomized motoneurons could be antidromically invaded only in the presence of synaptic facilitation. Electrophysiological explanations for the behavior of axotomized motoneurons in the alert cat are discussed in the text.

Abducens Nerve↗
PubMed1985

Morphological effects of VIth nerve section in the kitten as revealed by horseradish peroxidase.

The effects of the chronic section of the VIth nerve have been studied in kittens with the help of the horseradish peroxidase intra-axonal retrograde tracing method. Two months following the section of the VIth nerve, only 50% of the abducens motoneuron population was left. However, shapes, somata sizes and cell distribution through the nucleus of the remaining neurons were similar to those shown by controls. Functional implications of the findings are discussed.

Abducens Nerve Injury↗
PubMed1985

Praziquantel in the treatment of neurocysticercosis: long-term follow-up.

Thirty-five patients with active neurocysticercosis were treated with praziquantel and followed for 1 year after therapy. CT and CSF analysis showed that 91% of patients with parenchymal cysts improved, and 47% of patients with chronic arachnoiditis had remission. A single treatment with praziquantel for 2 weeks, administered in a daily dose of 50 mg/kg of body weight, was highly effective in parenchymal cysticercosis but less effective in meningeal cysticercosis. The benefits were sustained for at least 1 year.

Adolescent↗
PubMed1985

[Effects of axotomy on the activity of the motor neurons of the external ocular motor nucleus during saccadic movements].

The instantaneous firing frequency of cat abducens nucleus motoneurons (Mns) during spontaneous saccadic eye movements has been analyzed. Recordings were carried out from both control and axotomized Mns. Firing frequency of control Mns increased gradually during the first four to five interspike intervals, at which point maximum firing frequency was reached. Axotomized Mns showed an increase in firing frequency only up to the second or third interval, decreasing rapidly then. Linear relationships, with high correlation coefficients, were established between the first five intervals versus maximum frequency or peak eye velocity during saccades, in both control and axotomized Mns. However, the latter showed a decrease in the linear correlation from the third interval because of the decrease in the slope of the relationship. Functional implications of these results are discussed according to the present hypothesis on the effects of axotomy upon oculomotor neurons.

Abducens Nerve↗
PubMed1984

Therapy of parenchymal brain cysticercosis with praziquantel.

Twenty-six patients with cysticercosis of the brain parenchyma were treated with the antihelmintic agent praziquantel (50 mg per kilogram of body weight daily for 15 days). During treatment a strong inflammatory reaction occurred, as evidenced by increased protein and cells in the cerebrospinal fluid. This finding correlated with headache, exacerbation of neurologic symptoms, and edema and inflammation around cystic lesions. After three months of treatment all patients had improved clinically, and 13 (50 per cent) were asymptomatic. The total number of cysts on CT scans had decreased from 152 at the beginning of treatment to 51, and the mean diameter of cysts was reduced by 72 per cent. CT scans showed improvement in 25 of the 26 patients, with total remission of all cysts in nine. Seventeen control patients followed with CT studies for a mean of 9 +/- 2 months had no spontaneous remission of lesions, and in many cases the scans showed worsening during the observation period. Our results indicate that praziquantel is effective in cysticercosis of the brain parenchyma.

Adolescent↗
PubMed1983

Location of short neck muscle motoneurons in the cat as revealed by horseradish peroxidase.

The locations of short neck muscle motoneurons have been determined by means of the horseradish peroxidase technique. Although rectus capitis dorsalis major, rectus capitis dorsalis minor and obliquus capitis caudalis muscles have different functions implicated in head movements, their motoneurons are located in a common area of the ventromedial nucleus of the spinal cord, with no noticeable somatotopic organization. The three motoneuronal populations showed similar morphometric parameters with respect to soma size and shape. Some functional implications of the findings are discussed.

Animals↗
PubMed1982

Experimental infection with a Leptospira hardjo strain isolated from cattle of the eastern plains of Colombia.

The infectivity and pathogenicity of a strain of Leptospira hardjo isolated from the eastern plains of Colombia were evaluated. Ten pregnant heifers were artifically inoculated and monitored during 10 months. During the trial, isolation of leptospires was attempted and antibodies were detected by the microscopic agglutination test. Leptospires were recovered from the urine of six of the inoculated animals up to 6 months after infection. Eight of ten calves born from the inoculated heifers were born weak, and one of them died 12 h after parturition. Three of the weak calves had generalized jaundice of the internal surfaces. Half of the cows developed metritis and had a retained placenta. Serological reactions were seen against serotypes other than L. hardjo. A chronic infection was apparently established in the inoculated heifers with leptospiruria resulting in reinfection of the animals and a secondary rise in antibody levels.

Agglutination Tests↗