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Biomedical subjects

V M Rivera

Publications and source records attributed to V M Rivera.

At least 73 records · Page 4Linked to original sources
PubMed1980

Modified snake venom in amyotrophic lateral sclerosis. Lack of clinical effectiveness.

Diverse observations including neurological examination, manual muscle testing, quantitative electromyography, videotape esophagrams, and pulmonary function tests were used in a double-blind study evaluating the use of detoxified snake venoms as modified neurotoxin in 64 patients with amyotrophic lateral sclerosis (ALS) treated for six months. Transient periods of improvement were more common in the patients who received placebo. This study did not demonstrate any benefit from administration of modified snake venom to patients with ALS.

Amyotrophic Lateral Sclerosis↗
PubMed1979

Hereditary myoclonus and progressive distal muscular atrophy.

Myoclonus occurs in a variety of pathological conditions, some inherited. We recently evaluated 3 members of a Louisiana-Texas family with an autosomal dominant disorder manifested by adult-onset, generalized, stimulus-sensitive myoclonus and slowly progressive distal muscle weakness and wasting. The analyses of cerebrospinal fluid homovanillic acid and 5-hydroxyindoleacetic acid before and after probenecid provided some evidence of impaired turnover of central dopamine and serotonin. Treatment with clonazepam resulted in complete and lasting improvement of the myoclonus. A postmortem examination in 1 member of the family revealed chiefly neuronal degeneration of the anterior horn cells, Clark's nucleus, and the lower cranial nerve nuclei. A similar syndrome has not previously been reported.

Adult↗
PubMed1978

Computerized assessment of memory performance in dementia.

Memory deficits in demented patients were studied by applying a computerized system to titrate individual memory performance. Two delayed matching to sample tasks were used. ABA1 involved random visual shapes used as a measure of visual memory. ABA2 involved nonsense syllable trigrams used as a measure of verbal memory. A Human Test System panel with a display screen was utilized. This screen was a rear view projection window divided into four independent 3 X 2 sections arranged in a 2 X 2 matrix. The sample stimulus appeared on the upper left window for one second. The delay interval between stimulus sample and choices varied by 7 seconds dependent upon patient performance per trial. Also utilized was a color distractor task. Task parameters, data acquisition, retrieval, and graphic print-outs were all computerized. Individual titration levels reflected the severity of neurological impairment. Computerized assessment enabled subtle changes in memory performance to be readily identified. Implications for use of the system as a screening device in the assessment of mental changes in the elderly are apparent.

Aged↗
PubMed1978

Neuromyopathy in malignant hyperthermia.

A 31-year old male developed malignant hyperthermia (MH) during the initial minutes of Halothane induction. CPK rose to 6120 U/ml and decreased to normal levels as the patient became afebrile over a 10 day period of cooling measures and metabolic management. Muscle weakness, predominantly proximal and depressed deep tendon reflexes were found upon examination during convalescence. Muscle biopsy showed neurogenic changes characterized by fiber type grouping and targetoid fibers. CPK was elevated in one of the patient's children. This case supports the view of underlying hereditary neuromyopathy in MH.

Adult↗
PubMed1977

Precordialgia as a manifestation of vertebrobasilar insufficiency.

In 6 patients with vertebrobasilar insufficiency (VBI), precordialgia and autonomic-nervous-system manifestation such as diaphoresis and tachycardia were associated with the symptoms of VBI. Investigation ruled out cardiac and gastrointestinal causes. Possible mechanisms are discussed on the basis of intermitent ischemia of the central autonomic centers supplied by the posterior circulation.

Adult↗
PubMed1977

Risk factors in stroke in a Mexican-American population (Houston).

To date, there is little information available on stroke risk factors in a major ethnic minority such as Mexican-Americans (M-A) in the USA. Forty-three M-A patients were admitted to The Methodist Hospital and Ben Taub General Hospital (Houston) for a 12-month period, with diagnosis of atherosclerotic stroke. Thrombosis was diagnosed in 31 patients (72%), embolism from atherosclerotic sources in seven (16.4%), and parenchymal hemorrhage in five (11.6%). Hypertension was a common risk factor in all groups, being higher in hemorrhage followed by thrombosis and embolism. Arteriosclerotic heart disease was a common risk to all stroke types. TIAs, hyperlipidemia, diabetes, associated atherosclerotic lesions, smoking, obesity, erythrocytosis and sedentary life were significantly associated with embolism; less so with thrombosis or hemorrhage. Gout was only associated with thrombosis. These results indicate similar risk factors for Anglo-saxons and M-A in the USA with some minor differences between the Mexican and the USA stroke series.

Adult↗
PubMed1975

Patterns of memory performance in the neurologically impaired aged.

The specific behavioral manifestation associated with the different disorders producing the syndrome of dementia have remained poorly investigated. We examined the memory performance of three distinct groups of patients with dementia secondary to Alzheimer's disease (AD) multiple-infarctions (MID) and vertebrobasilar insufficiency (VBI) on the ten subtests of the Wechsler Memory Scale (WMS). Statistical methods of analysis were used to maximize the differences between the groups. Univariate statistical procedures revealed that the AD group performed significantly and consistently lower than the two cerebrovascular groups. There were no significant differences between the two cerebrovascular disease groups, even though the MID group tended to perform consistently more poorly than the VBI group. For heuristic and conceptual purposes as well as to determine which combination of the ten WMS variables produced the "best" statistical model differentiating the groups the data was analyzed by multivariate techniques. A discriminate function analysis obtained a 100% valid positive hit rate in discriminating among the three groups. One hundred percent diagnostic accuracy was also obtained in discriminating between MID and AD as well as AD and VBI. The two cerebrovascular groups tended to overlap in their probability distributions with an 81% hit rate. Different predicitive statistical models were identified to differentiate the various diagnostic groups. It was possible to discriminate the three diagnostic groups by different patterns of memory performance.

Age Factors↗
PubMed1975

Analysis of intellectual and cognitive performance in patients with multi-infarct dementia, vertebrobasilar insufficiency with dementia, and Alzheimer's disease.

A prominent feature in dementia is intellectual deterioration. Review of the clinical literature indicates a lack of suitably quantitated studies of specific intellectual defects in dementia. The present study investigated the performance of patients with multi-infarct dementia (MID), dementia due to Alzheimer's disease (AD), and vertebrobasilar insufficiency (VBI) with dementia using the Wechsler Adult Intelligence Scale (WAIS). Forty-two patients ranging in age from 45 to 85 years (x 66) were included. Significant differences in cognitive and intellectual performance were found between patients with dementia due to VBI and MID versus neuronal atrophy of the Alzheimer's type. The group with AD performed significantly and consistently lower on all measures. There were no significant differences between the two cerebrovascular disease groups, even though the MID group performed consistently more poorly than the VBI group. A discriminant function analysis classified 74% of the patients correctly based on the individual WAIS scores. The diagnosis was more easily made when tasks measuring visual motor coordination and abstract reasoning were included in the analysis.

Age Factors↗