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Biomedical subjects

M D O'Brien

Publications and source records attributed to M D O'Brien.

At least 37 records · Page 2Linked to original sources
PubMed1993

Trigeminal nerve section for chronic migrainous neuralgia.

We report a series of 14 patients who underwent partial or complete trigeminal nerve root section for chronic unremitting migrainous neuralgia. They had all suffered attacks with severe pain for over 18 months without remission (mean duration 5.5 years). Symptoms were refractory to extended medical intervention and had caused prolonged disruption of lifestyle. The sensory root was completely divided in two cases with complete relief of pain (mean follow-up period 5.6 years). In the other 12 patients, 50-90% of the superomedial portion of the sensory root was divided. Of these, five received no further surgery, and experienced complete (n = 2), near complete (n = 2), or incomplete (n = 1) relief of neuralgia (mean follow-up 5.5 years). The remaining seven patients in the partially divided group were not relieved of pain after operation (n = 5) or suffered early recurrence of pain (n = 2). They showed incomplete sensory loss in the first trigeminal division (V1) and had a second operation to extend the nerve division. V1 anaesthesia was established in all cases after the second procedure, and as a result, four are currently completely free of pain and one has near complete relief of pain. The remaining two patients are still experiencing severe neuralgia (mean follow up 4.1 years). Twelve out of 14 patients (85.7%) receiving surgery for chronic migrainous neuralgia experienced adequate pain relief and are able to follow a normal life (mean follow up 5.6 years). Corneal abrasion was the commonest long-term complication, occurring in three cases (28.5%) and progressing to chronic keratitis in one. We conclude that total trigeminal nerve root section is an effective treatment for patients suffering from chronic migrainous neuralgia and can be safely offered as a primary surgical treatment.

Adult↗
PubMed1992

Familial periodic cerebellar ataxia: a problem of cerebellar intracellular pH homeostasis.

Six affected members of two families with familial periodic cerebellar ataxia were relieved of their symptoms with oral acetazolamide. Phosphorus 31 (31P) nuclear magnetic resonance spectroscopy showed abnormal intracellular pH levels in the cerebellum of all subjects when they were not treated. These levels returned to normal with treatment. Cerebral pH values were also measured in one family and were normal before and after treatment. An additional 3 patients with similar attacks, but without a family history, had normal untreated pH values in the cerebellum and cerebrum.

Acetazolamide↗
PubMed1991

Persistent superior oblique paresis as a manifestation of familial periodic cerebellar ataxia.

A brother and sister complained of persistent diplopia due to superior oblique palsies. The cause of their symptoms became apparent when they were diagnosed as having familial periodic cerebellar ataxia (FPCA), a rare autosomal dominant condition. Oral acetazolamide (250 mg twice daily) not only prevented all the periodic symptoms but also relieved their diplopia, which had been present between attacks.

Acetazolamide↗
PubMed1986

Leukocyte survival in cerebrospinal fluid.

Delays in the laboratory examination of cerebrospinal fluid are commonly encountered in clinical medicine. The present studies were designed to evaluate changes in cerebrospinal fluid leukocyte counts relative to time elapsed before analysis. Neutrophil counts decreased most rapidly, being 68 +/- 10% (standard error of the mean) and 50 +/- 12% of initial values at 1 and 2 h, respectively. Lymphocyte and monocyte numbers were not significantly altered until 3 h.

Cell Survival↗
PubMed1986

Dystonia of the legs induced by walking or passive movement of the big toe in a patient with cerebellar ectopia and syringomyelia.

A 45-year-old man with dystonia of the legs was found to have cerebellar ectopia and syringomyelia. Both walking and passive movements of the big toes evoked dystonic postures of the legs. Electrophysiologic studies suggested that the dystonic movements were reflex in origin. We propose that the cervical spinal cord lesion, involving propriospinal pathways, resulted in an abnormal response of spinal interneurons to peripheral stimuli.

Cerebellar Diseases↗
PubMed1984

Whole blood cyanide levels in patients with tobacco amblyopia.

Three patients presented with painless bilateral visual failure due to tobacco amblyopia. The whole blood cyanide levels were raised above those predicted from their high tobacco consumption, approaching lethal levels reported from acute inhalation of cyanide. Each patient had an excessive alcohol intake with biochemical evidence of hepatic dysfunction, the elevated whole blood cyanide levels being attributed to the associated impairment of cyanide detoxification. In each case the improvement in visual acuities following abstinence and hydroxycobalamin therapy was accompanied by a reduction in the whole blood cyanide level to within the normal range. Serial measurements of whole blood cyanide, serum alcohol, and the detection of urinary nicotine provided valuable indices of the patient's subsequent compliance and clinical progress.

Adult↗
PubMed1983

The effect of hypertension on ischemic cerebral edema in spontaneously hypertensive rats.

Cerebral ischemia was produced in spontaneously hypertensive rats (SHR) with a range of blood pressures (BP). Measurements were made at 4 hours of the edema produced (% H2O), the damage to the blood brain barrier (BBB) and, the blood flow (CBF) in both hemispheres and the cerebellum and brain stem. There was a statistically significant correlation between CBF and BP and between CBF and % H2O, but the correlation between BP and % H2O was not significant. The BBB is not open to technecium pertechnetate in this model at this time interval. Systemic hypertension is not a significant factor in the early development of ischemic edema in this model because the blood flow in the ischemic area falls with rising blood pressure, probably due to autoregulation in the collateral circulation.

Animals↗
PubMed1983

The purification, characterization and amino acid analysis of nuclear ribonuclear protein and Sm antigens reacting with human autoimmune sera.

'Monospecific' antibodies directed against nuclear ribonucleoprotein (nRNP) and Smith (Sm) antigens from the sera of patients with mixed connective tissue disease (MCTD) and systemic lupus erythematosus (SLE) were used to isolate and purify the respective antigens from calf thymus nuclear extracts. The antibodies were allowed to interact with the nuclear antigens and the resulting complexes were purified by Protein-A-Sepharose and poly-U-Sepharose chromatography. When the Protein-A-Sepharose antigen-antibody complex was sequentially eluted with 20% and 60% ethylene glycol, 2 fractions could be identified, one containing antigenically active Sm and the other antigenically active Sm and nRNP. The nRNP fraction contained 5 major proteins with mol. wts ranging from 38,000 to 150,000. The Sm antigen had a mol. wt of 68,000 and was noted to 'co-purify' with the nRNP antigen. Amino acid analysis of the purified proteins demonstrated a high content of glycine, serine and acidic amino acid residues similar to previously described core proteins of heterogeneous nuclear RNP (hnRNP), a precursor to mammalian messenger RNA. Analysis of the RNA moiety following nuclease phosphorylase reactions demonstrated the presence of a RNA polynucleotide with a 'capped' structure at the 5' terminus, a feature consistent with the concept that the nRNP antigen is part of the hnRNP complex.

Amino Acids↗
PubMed1981

Benign familial tremor treated with primidone.

Primidone given to a patient for epilepsy produced an unexpected reduction in benign familial tremor. Over the next eight years the drug was therefore tried in a prospective study of 20 other patients with benign familial tremor alone. Of these, six could not tolerate the drug because of vertigo and nausea but 12 obtained a good response, which in some cases was dramatic. Investigations in two patients suggested that the effect was mediated predominantly by derived phenylethylmalonamide, though primidone had some effect, since tremor recurred slightly on withdrawing the drug despite a constant or rising blood phenylethylmalonamide concentration. Primidone is highly effective in benign familial tremor. More patients with the condition are intolerant of the drug than are usually found with epilepsy.

Adolescent↗