Search PubMed⌕ Search

Biomedical subjects

M Brin

Publications and source records attributed to M Brin.

At least 19 recordsLinked to original sources
PubMed1995

Dyspnea in dystonia. A functional evaluation.

BACKGROUND: Dystonia consists of action-triggered sustained focal muscle contractions, worsened by effort, and resulting in voice changes, abnormal posturing, and dyspnea. The cause of dyspnea, previously unexplained, is the basis of this report. METHODS: Since the maximal efforts required to perform pulmonary function testing (PFT) could worsen the muscular contractions in dystonic patients, we used several tests to identify possible causes of dyspnea. These included spirometry with flow volume loops (FVL), tidal volume breathing, maximum voluntary ventilation (MVV), and inspiratory and expiratory muscle pressures (PImax, PEmax), sitting and supine. We used cycle ergometry with arterial blood gas (ABG) values to detect cardiac/pulmonary limitations and respiratory inductive plethysmography (RIP) to assess chest wall/abdominal movements for synchrony. Dynamic videofluoroscopy (VF) assessed and recorded the action-triggered muscle activity of the upper airways and the diaphragm during quiet breathing, speech, swallowing, and maximal respiratory maneuvers similar to the efforts required during PFT. RESULTS: Twenty-six dystonic patients, 12 women and 14 men, ages 14 to 70 years (mean age, 52.3 years) were evaluated. Their neurologic classification included 22 primary (idiopathic) and 4 secondary (2 postneuroleptic use, 2 posstraumatic). Four patients originally classified as having focal dystonia had dyspnea and were found to have diaphragmatic and/or upper airway dysfunction too. The PFTs showed abnormal FVL and/or tidal volume breathing patterns, with intermittent interruptions of air flow during inspiration or expiration in 20 of 24 patients. The VF was abnormal in 24 of 26 patients: 19 patients had combined upper airway (UA) and diaphragmatic dysfunction (DD); 1 patient had UA dysfunction alone, and 4 patients had DD alone. Except for poor effort and/or dystonic movements, cycle ergometry was normal in 18 of 21 patients. The ABG values and/or pulse oximetry were normal in 19 of 22 patients. CONCLUSION: Dyspnea in dystonia appears to be due to excessive and/or dysynchronized contractions of the upper airways and/or diaphragm, with usually normal gas exchange. These spasmodic and irregular muscular contractions during speech and daily activities are associated with the sensation of excessive effort to overcome the spasms. Excessive spasms can be triggered during PFT and are best detected on FVL patterns coupled with dynamic VF.

Adolescent↗
PubMed1994

Botulinum toxin A for hyperkinetic facial lines: results of a double-blind, placebo-controlled study.

Previous work on patients with muscular dystonia has shown that small intramuscular doses of botulinum toxin A eliminated hyperkinetic facial lines for approximately 6 months. The purpose of this study was to determine the efficacy of botulinum toxin A injections in eliminating facial wrinkles in aesthetic surgery patients who do not have muscular dystonia. Eleven healthy subjects were studied in a double-blind fashion. On both sides of the face, 0.2 cc of either normal saline or botulinum toxin A was injected into the forehead or into the periorbital wrinkles (crow's feet). Documentation of results was made by photographs taken of the patients during repose and during facial animation before and after injection. Assessment of facial wrinkles was done from a grading system in which the patient and the facial plastic surgeon were asked to judge the severity of the wrinkles on a scale from 0 to 3, with 0 reflecting no facial wrinkles and 3 reflecting severe facial wrinkling. Nine of 11 subjects injected with botulinum toxin A noted a significant improvement in the severity of their facial wrinkles in comparison with the side of the face injected with saline, with a rating improvement of 2 points. Two of 11 subjects noted a moderate improvement, with a rating improvement of 1 point. No patient injected with saline reported an improvement in the severity of the facial wrinkles on the control side. There were no serious complications. Botulinum toxin A is an efficacious method of nonsurgically eliminating facial wrinkles and may play a role in the cosmetic enhancement of the aging face.

Adult↗
PubMed1992

Essential tremor.

Explore the source record for details and available documents.

Data Collection↗
PubMed1991

Dopamine beta-hydroxylase gene excluded in four subtypes of hereditary dystonia.

The hereditary dystonias include a clinically heterogeneous group of movement disorders varying in symptoms, age of onset, and drug responsiveness. Dopamine beta-hydroxylase (DBH), the enzyme that converts dopamine to norepinephrine, has been implicated in dystonia because of increased serum levels of DBH in some patients, the influence of catecholaminergic drugs on the human phenotypes, and altered norepinephrine levels in several brain regions in dystonia patients and in genetically dystonic rodents. In addition, markers linked to the dystonia gene in two ethnic groups map close to the DBH locus on human chromosome 9q34. Here we evaluate the inheritance of restriction fragment length polymorphisms near the DBH gene in families with four subtypes of hereditary dystonia: Jewish and non-Jewish, early onset, generalized idiopathic torsion dystonia (ITD); dopa-responsive dystonia; and myoclonic dystonia. In all families, obligate recombination events were observed between the DBH and dystonia genes, thus excluding the DBH gene as the primary defect.

Adolescent↗
PubMed1991

Apolipoprotein synthesis in normal and abetalipoproteinemic intestinal mucosa.

The genetic disease abetalipoproteinemia is characterized by a total absence of apolipoprotein B-containing lipoproteins from plasma. A presumed synthetic defect in apolipoprotein B synthesis was thought to be responsible for this disorder. The present study quantitates apoprotein B synthesis and apolipoprotein B messenger RNA levels in duodenal mucosa from normal patients and four patients with abetalipoproteinemia. After in vitro [3H]leucine incorporation, small intestinal biopsy specimens from three of four patients with abetalipoproteinemia synthesized immunoprecipitable apolipoprotein B of identical mobility (on sodium dodecyl sulfate gel electrophoresis) to normal apolipoprotein B. In abetalipoproteinemia, the apolipoprotein B content of intestinal mucosa by radioimmunoassay was 15% of normal mucosal values, whereas apolipoprotein B messenger RNA quantitation showed 3-20-fold increased levels compared with normal mucosa. In one patient, smaller-molecular-weight fragments of apolipoprotein B were immunoprecipitated from duodenal biopsy specimens. The synthesis rates and messenger RNA levels of two other chylomicron apoproteins (apolipoprotein A-I and apolipoprotein A-IV) were found to be reduced by 50%. These results show the synthesis of immunologically recognizable apolipoprotein B48 in abetalipoproteinemia. The significance of mucosal apolipoprotein B content in abetalipoproteinemia is discussed in terms of factors controlling apolipoprotein B synthesis in normal mucosa and in abetalipoproteinemia.

Abetalipoproteinemia↗
PubMed1990

Double-blind, placebo-controlled trial of botulinum toxin injections for the treatment of spasmodic torticollis.

We enrolled 55 patients in a double-blind, placebo-controlled, parallel design study of the effectiveness of botulinum toxin (Botox) injections for the treatment of spasmodic torticollis. Patients received a standard series of injections, either placebo or Botox. We determined the sites of injection and dose per muscle by the nature of head deviation. Compared with placebo, Botox produced statistically significant improvement in the severity of torticollis, disability, pain, and degree of head turning. There were no serious side effects. During the double-blind phase, 61% of patients injected with Botox improved; 74% of patients subsequently improved during a later open phase at a higher dose of Botox. Direction of head turning, severity of torticollis, and presence or absence of jerky movements did not significantly influence the response rate. We conclude that Botox is a valuable treatment for spasmodic torticollis.

Analysis of Variance↗
PubMed1988

Primary lateral sclerosis. A clinical diagnosis reemerges.

Adults with slowly progressive noninherited gait disorders may show no abnormalities on examination other than signs implicating the corticospinal tracts. That is the syndrome of "primary lateral sclerosis" (PLS), a clinical diagnosis that has been avoided because it is a diagnosis of exclusion, proven only at autopsy. Now, modern technology can exclude other disorders that can cause the syndrome with an accuracy of about 95%. That serves to eliminate the following: compressive lesions at the foramen magnum or cervical spinal cord, multiple sclerosis, amyotrophic lateral sclerosis, Chiari malformation, syringomyelia, biochemical abnormality, and persistent infection with human immunodeficiency virus or human T-lymphotrophic virus type I. We studied three autopsy-proved cases of PLS; six living patients in whom PLS was diagnosed clinically after comprehensive evaluations that excluded the alternative diagnoses; and two patients with this syndrome of PLS and antibodies to human immunodeficiency virus seropositivity that clinically resembled PLS. Primary lateral sclerosis is now a respectable and permissible diagnosis.

Adult↗
PubMed1986

Biotin-responsive encephalopathy with myoclonus, ataxia, and seizures.

Prominent neurological abnormalities, including myoclonus, seizures, ataxia, and hearing loss, have been noted in juvenile-onset biotin-responsive MCD. The underlying defect in many of these patients, who generally present in the first year of life, appears to be a deficiency of biotinidase. We have presented a young woman with adult-onset myoclonus, ataxia, hearing loss, seizures, hemianopia, and hemiparesis who responded to pharmacologic dosages of biotin. Although she displayed many of the clinical and biochemical features of juvenile-onset MCD, she did not have a biotinidase deficiency, and the underlying defect remains to be determined. Because of her response to biotin, we have advocated that other patients with unexplained myoclonus syndromes be evaluated for biotin-dependent carboxylase deficiencies and undergo a therapeutic trial with biotin.

Adult↗
PubMed1983

Drug--vitamin B6 interaction.

In conclusion, there are several drug types that can interfere with vitamin B6 metabolism. In most cases, the interaction involves a complex formation between the drug (or a derivative) and the reactive coenzyme PLP, resulting in a Schiff base. Such an interaction leads to an inactivation of PLP (and also of the drug). Other types of interaction involve (a) stimulation of vitamin B6-dependent pathways and (b) competition with PLP for the binding site on the enzyme. Examples of the above are the steroid hormones (oral contraceptives). In most instances, overt symptoms of vitamin B6 deficiency due to chronic ingestion of these drugs are observed, and neurological problems seem to be rather frequent. Because of the reactive nature of the coenzyme PLP and the ease with which it can interact with drugs, sub-clinical (marginal) vitamin B6 deficiency should be suspected in the absence of overt clinical signs. Once the vitamin B6 problem has been identified, the condition can usually be treated by judicious use of large doses of vitamin B6 without compromising the clinical efficacy of the drug.

Contraceptives, Oral↗
PubMed1982

Thiamin in the elderly--relation to alcoholism and to neurological degenerative disease.

Status of thiamin in the elderly North American population is reviewed. Most Americans eat sufficient thiamin but about 5% of those over 60 yr old show impaired thiamin status. This is more marked in the poor, those confined in institutions, or those with illness. Thiamin responsive heart disease and Wernicke Korsakoff CNS syndromes occur in the elderly but there is no increased prevalence. Minor heart or neurological syndromes related to thiamin deficiency cannot be identified. The Recommended Dietary Allowance of thiamin provides at least 50% excess thiamin for those over 60 yr old--this amount is adequate. There is no known toxicity for thiamin.

Adolescent↗
PubMed1982

Biopotency of alpha-tocopherols as determined by curative myopathy bioassay in the rat.

The decrease in plasma pyruvate kinase activity after administration of various tocopherols to vitamin E-deficient rats provided the basis for a 3-point parallel-slope assay for vitamin E activity. Based on 6 replicate assays, RRR-alpha-tocopheryl acetate (RRR-alpha-TA) was 141% as active as all-rac-alpha-tocopheryl acetate (all-rac-alpha-TA). This confirms many previous reports with other bioassays and is in agreement with the unit-weight relationships assigned by The National Formulary. 2-ambo-alpha-Tocopheryl acetate was 97% as active as all-rac-alpha-TA indicating that only the configuration of the 2-position on the chromanol ring is important in determining the biological activity of alpha-tocopherol.

Animals↗
PubMed1982

[Cerebral metastases of malignant germinal tumors of the testis].

Cerebral metastases occur in 6% of cases of testicular cancer. In our study of 5 cases they occurred during the course of the disease (with a delay of 4-18 months, at the same time as pulmonary and abdominal metastases). The prognosis in these cases is poor (presence of choriocarcinomatous or vitelline elements, advanced stages). The diagnosis is easily established (clinical, encephalogram, scanner); the prognosis is hopeless (5 deaths in 3-90 days). When a metastasis is the first diagnostic clue (one case), the prognosis is slightly better (9 month survival). The incidence of cerebral metastasis is the same now as it was before the introduction of effective chemotherapy in patients who die from testicular cancer, but the death rate from this malignancy has decreased since the introduction of active chemotherapy with cisplatin. Hence, there is no indication for prophylactic treatment for cerebral metastases in patients in remission since metastases only appear in cases which are resistant to treatment.

Abdominal Neoplasms↗