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Biomedical subjects

W S Fields

Publications and source records attributed to W S Fields.

At least 37 records · Page 2Linked to original sources
PubMed1986

Thoracic outlet syndrome: review and reference to stroke in a major league pitcher.

The thoracic outlet compression syndrome is reviewed. It should be considered in all neurologic and vascular complaints of the upper extremity. Symptoms are related to arm position and use and are aggravated by sustained activity that stresses the shoulder. A participant in any sport that requires a repetitive violent throwing motion is a potential candidate for this condition. A detailed report of a major league pitcher illustrates the importance of early diagnosis and appropriate treatment, inasmuch as delay can be catastrophic, as in the case of this career athlete. A thorough history is the best aid in arriving at a diagnosis. When the symptoms are mild or moderate, conservative therapy may suffice. When surgery is indicated, the object is to create adequate space for passage of the brachial plexus, subclavian artery, and subclavian vein. Patients with thrombosis and occlusion of a major artery supplying the upper extremity require an additional arterial reconstructive procedure plus a cervicothoracic sympathectomy.

Adult↗
PubMed1986

Treatment-related leukoencephalopathy. A study of three cases and literature review.

The etiology and pathogenesis of treatment-related leukoencephalopathy remain obscure. The evidence is substantial, however, that radiation therapy in combination with higher cerebral concentrations of certain chemotherapeutic agents such as MTX increases the likelihood of permanent damage. There is no therapy of apparent benefit for treatment-related leukoencephalopathy, but reasonable alternatives include 1) withholding chemotherapy and/or radiation, 2) administering calcium leucovorin in high doses intravenously in methotrexate-induced leukoencephalopathy (26), or 3) perfusing the subarachnoid space (2) from above through an Ommaya reservoir and out from below through a lumbar puncture needle or lumbar subarachnoid catheter. Because CT scan abnormalities and subtle mental or intellectual changes are often noted before the full-blown clinical presentation, a prospective study involving periodic CT scanning as well as formal neuropsychologic testing appears worthwhile in all patients who are to receive cranial irradiation and/or chemotherapy in the prophylaxis or active treatment of CNS disease in order to detect and perhaps even to prevent this adverse side effect of cancer therapy.

Adolescent↗
PubMed1986

Multi-infarct dementia.

The participation of vascular disease in elderly dementia has been clarified to a significant degree in the past decade. The term multi-infarct dementia implies that severe mental impairment can result from thrombosis of large and medium arteries or from multifocal emboli of either cardiac or arterial origin. This is markedly different from the concept, which, unfortunately, is still the generally current view in the lay press, in some medical journals, and in advertisements of pharmaceutical companies, that gradual narrowing of cervical and cerebral arteries produces chronic hypoperfusion of the brain and is the basis of mental deterioration. This concept of generalized cerebral arteriosclerosis or arteriosclerotic dementia is no longer acceptable. Most patients with MID can be distinguished from those suffering from other types of dementia by employing a clinical ischemic score supplemented by electrophysiologic studies, CCT, and neuropsychological testing. Furthermore, the association of MID with severe hypertension and thromboembolism makes early diagnosis imperative, because appropriate treatment may arrest progression and even provide some improvement.

Aged↗
PubMed1985

Central nervous system toxicity with high-dose Ara-C.

We evaluated the CNS complications in 118 adults with acute leukemia who received IV high-dose Ara-C therapy. Fourteen (12%) had cerebellar signs, encephalopathy, seizures, or leukoencephalopathy. Symptoms usually occurred within 24 hours after the last treatment. Patients receiving a cumulative dose in excess of 24 g/m2 had more severe or irreversible symptoms. After lower cumulative doses, symptoms often resolved even though treatment was continued. The incidence of CNS complications of high-dose Ara-C is acceptable and is potentially reversible if appropriate precautions are taken.

Adolescent↗
PubMed1985

Does platelet antiaggregant therapy lessen the severity of stroke?

Data from the Aspirin in Transient Ischemic Attack (AITIA) study, an ongoing study of two platelet antiaggregant drugs, and other published therapeutic trials were reviewed to determine whether the severity of stroke is reduced in patients taking platelet antiaggregants. Data from three of four studies suggest that strokes in treated patients are less severe than those in untreated patients. Further studies evaluating platelet antiaggregant therapy should include assessment of the severity as well as the incidence of stroke.

Aspirin↗
PubMed1984

A phase II trial of 2,5,-diaziridinyl 3,6-bis (carboethoxy amino) 1,4-benzoquinone (AZQ, NSC 182986) in recurrent primary brain tumors.

Forty-one patients with recurrent primary malignant brain tumors were treated with 2,5-diaziridinyl 3,6-bis (carboethoxyamino), 1,4-benzoquinone (AZQ) at an initial dose of 6-8 mg/m2/day X 5 days. Courses were repeated monthly upon recovery of myelosuppression. Six of 25 evaluable patients (24%) showed definite tumor regression, and 7 (28%) showed disease stability as determined by monthly CT scans and neurologic examination. For all patients receiving one course of AZQ, the response rate was 16% (6 of 37 patients) and the stable disease rate 19%. The estimated median time to tumor progression with AZQ was 54 weeks for the responding patients and 36 weeks for the stable patients. Toxicity consisted of myelosuppression, primarily thrombocytopenia, which was delayed and cumulative. Other toxicities were uncommon. Further clinical trials in patients with malignant primary brain tumors, including combination studies with other drugs, are indicated.

Adolescent↗
PubMed1984

The significance of carotid stenosis or ulceration.

Data from the medical treatment group of the Aspirin in TIA study were reviewed, and prospective analysis of patients with asymptomatic bruits was performed to see whether carotid stenosis (0 to 49% or 50 to 99%) or ulceration produced an increased risk of ipsilateral TIA or infarct. In symptomatic arteries, greater than 50% stenosis without ulceration implied a higher risk of subsequent symptoms. Ulceration was associated with an increased risk only in nonstenotic vessels. Lesion anatomy was not related to outcome in asymptomatic arteries, and the incidence of cerebral infarct was low. Factors other than anatomy must play a large role in determining subsequent risk.

Angiography↗
PubMed1983

Aspirin for prevention of stroke: a review.

Most neurologists concede that thromboembolism is the principal pathogenetic mechanism for ischemic cerebrovascular disease, including both transient ischemic attacks and cerebral infarction. Surgical removal of atherosclerotic lesions may eradicate the site of origin of emboli, but a safer and more rational approach may be found in using antithrombotic drugs. Aspirin has been shown in clinical trials to be an effective agent in treating transient ischemic attacks and preventing infarction. An apparent difference in response between men and women patients was found in the results of one large study but not substantiated by others. It has been suggested that a lower dose of aspirin than that used in these trials may be equally or more effective. This proposition still needs to be tested in a clinical trial.

Aspirin↗
PubMed1983

The pharmacologic fate of 2,5-diaziridinyl-3,6-bis(carboethoxyamino) 1,4-benzoquinone (AZQ NSC-182986) by intracarotid or intravenous administration in beagles.

Beagle dogs received either intravenous (I.V.) or intracarotid (I.C.) 14C ring labelled 2,5-diaziridinyl-3,6-bis-(carboethoxyamino) 1,4-benzoquinone (AZQ) at a dose of 2 mg/kg. Blood, urine and cerebrospinal fluid (CSF) samples were collected at intervals. At varying times, dogs from each group were sacrificed and histologic examination and drug determinations were performed on the major organs. By both routes of administration, the elimination of AZQ from plasma was biphasic with an initial half-life of 18 min and a terminal half-life of 26 hr. The apparent volume of distribution was 7.9 l/kg and the total clearance was 3.5 ml/kg/h. The 96 hr cumulative urinary excretion of total 14C was 41% of the administered dose, including 4% as the unchanged drug. At 1, 48, and 96 hr after I.C. AZQ, drug concentrations in the brain tissue were twice those by the I.V. route. High drug concentrations in the CSF were produced by both routes, although the CSF to plasma ratio was higher by I.C. than I.V. In extracranial organs, tissue concentrations of AZQ were at least twice as high by I.V. than by I.C. administration. No significant clinical or neurologic toxicity were noted when AZQ was given I.C. In the dog I.C. administration of AZQ seems to accelerate drug entry into the brain tissue.

Animals↗
PubMed1982

Pituitary apoplexy complicating chronic secondary amenorrhea.

Three young women who developed amenorrhea secondary to large, unsuspected pituitary tumors are described. They presented with acute onset of the triad of headache, nausea and vomiting, and visual abnormalities. One patient died; the other two retained some sequelae, and one had a significant hemiparesis. These devastating effects of pituitary apoplexy can be avoided in amenorrheic patients if the possibility of a pituitary tumor is considered early on. Lateral skull x-ray examinations are inexpensive an easily obtained and will usually demonstrate significant pituitary tumors. Early recognition and surgical removal of pituitary tumors carries low morbidity and mortality and will avoid an apoplectic crisis.

Adult↗
PubMed1981

[Medical or chirurgical treatment in transient cerebral ischemia? (author's transl)].

When a physician is faced by a patient suffering from transient ischemic attacks, the diagnosis is almost invariably determined by the clinical history. It becomes necessary to eliminate certain other medical conditions including migraine, focal epilepsy and cardiac disorders. Once he is satisfied with the diagnosis of TIA, then he must consider whether to employ medical or surgical therapy or a combination of both. It must be recognized that TIAs are not benign events since more than 50 p. 100 of individuals who develop completed strokes will have antecedent TIAs. Identification of the pathogenetic mechanism becomes important in choosing the specific therapy. Where the origin of the attacks is clearly thromboembolic, secondary to atherosclerosis, surgical intervention may be appropriate if the lesion is readily accessible. However, consideration of surgery is also determined by the risk of post-operative stroke or death at the hands of less experienced surgeons. The risk of stroke in a patient who is having frequent TIAs may be reduced initially by utilizing anticoagulants for a limited period. Long-term medical therapy requires the use of anti-platelet agents which have been shown to have a more beneficial effect in preventing strokes in men. The evidence for protection in females is less satisfactory. Surgical treatment should be followed by long-term medical therapy since it is very unlikely that only one lesion is present in a high-risk patient. It is still clear that the best way to manage cerebro-vascular accidents is to prevent them. This requires education of the public, as will as physicians, with respect to risk factors and the value of various modes of therapy.

Aged↗
PubMed1980

Persistent hypoglossal artery in association with advanced atherosclerosis.

The persistent hypoglossal artery is an anomaly of great interest which probably becomes clinically significant only when it is associated with occlusive cerebrovascular disease or some other life-threatening vascular abnormality such as intracranial aneurysm on the same side in the carotid-middle cerebral artery territory. In the case reported here it was apparently of no clinical importance in spite of associated atherosclerosis and thrombosis.

Aged↗
PubMed1980

Controlled trial of aspirin in cerebral ischemia.

The findings from a double-blind multicenter clinical trial of aspirin for treatment of cerebral ischemia are reviewed. Of 303 patients who had carotid transient ischemic attacks (TIAs), 125 were selected for carotid reconstructive surgery and were then randomly assigned treatment with aspirin or placebo. The remaining 178 patients were also randomly assigned to an aspirin or placebo regimen. Analysis of the first 6 months of follow-up showed a differential in favor of aspirin when death, nonfatal cerebral or retinal infarction and the occurrence of TIAs were grouped and considered together as end points. Restriction of end points to death or nonfatal cerebral or retinal infarction yielded no statistically significant differential between the aspirin and placebo groups. After these results were published, a study group from Canada reported that aspirin was effective in preventing threatened stroke, but that this effect was limited to males. Review of our nonsurgical group with respect to sex shows findings consistent with those of the Canadian study for the end points of stroke or death. Inclusion of the occurrence of TIAs in the group of end points, however, revealed that aspirin is effective in females as well as males.

Actuarial Analysis↗