PubMed Health⌕ Search

Biomedical subjects

D Chyatte

Publications and source records attributed to D Chyatte.

At least 37 records · Page 2Linked to original sources
PubMed1992

Encephalo-omental synangiosis in the management of moyamoya disease.

Moyamoya disease is a chronic occlusive cerebrovascular disorder characterized by stenosis of the intracranial internal carotid artery often accompanied by stenosis of the anterior and/or middle cerebral arteries. This results in cerebral ischemia, which manifests clinically as transient, repetitive episodes of hemiplegia, dysarthria, and involuntary movements. This case report documents a patient in whom an initial extracranial-intracranial bypass (superficial temporal-middle cerebral artery) failed to alleviate the ischemic symptoms. In a subsequent procedure, a pedicle graft of omentum was created and through a subcutaneous tunnel was placed on the right cerebral cortex. Over a 2 1/2-year period, this has resulted in a dramatic resolution of the patient's symptomatology. The report delineates the condition and reviews other therapeutic options.

Adult↗
PubMed1991

Mechanisms of glove tears and sharp injuries among surgical personnel.

OBJECTIVE: --The development of strategies to prevent exposure to blood for operating room personnel has been hampered by a lack of knowledge about the specific mechanisms of exposure. The purpose of this study was to classify the mechanisms of glove tears and sharp injuries in the operating room. DESIGN: --During a 3-month period, a nurse interviewed operating room personnel immediately after a glove tear or sharp injury had occurred. SETTING: --Yale-New Haven (Conn) Hospital is a tertiary care teaching hospital. RESULTS: --There were 249 glove tears and 70 sharp injuries. Visible skin contact with the patient's blood occurred in 156 glove tears (63%). The mechanism causing the tear could be identified in only 81 (33%). For 230 glove tears (92%), personnel were wearing single gloves. Of 70 sharp injuries, 47 (67%) were caused by needles and usually occurred during suturing. The following three mechanisms accounted for 40 sharp injuries (57%): (1) hands injured while stationary and holding an instrument, 11 (16%)-a position of risk not previously identified; (2) hands injured while retracting tissue, 12 (17%); and (3) injuries caused by sharp instruments not being used, 17 (24%). Instrument passage caused only four sharp injuries (6%). CONCLUSIONS: --The majority of glove tears have an unknown mechanism, and alteration in the manufacture or number of gloves worn may be helpful in reducing cutaneous blood exposures. The identification of specific mechanisms of sharp injuries should lead to effective strategies to prevent exposure to the human immunodeficiency virus and other blood-borne pathogens in the operating room.

Accidents, Occupational↗
PubMed1990

Patterns of failure of aspirin treatment in symptomatic atherosclerotic carotid artery disease.

Over a 24-month period, 291 patients were consecutively admitted to the West Haven Veterans Administration Medical Center with new ischemic neurological symptoms. Of these, 90 patients (31%) developed ischemic neurological symptoms while taking aspirin (aspirin treatment failure). Of those in whom aspirin treatment failed, 66 patients had ischemic symptoms in the distribution of the carotid artery. Aspirin treatment failed in 21 patients with severe carotid stenosis (greater than 75% stenosis). Eleven of these 21 patients had cerebral infarctions while taking aspirin, and 7 of these 11 infarcts occurred without the prior warning of transient ischemic attacks. Aspirin treatment failed in 45 patients with lesser degrees of carotid stenosis. Transient ischemic attack without permanent ischemia was the most common manifestation of failure in these patients. Infarction occurred in only 12 of these 45 patients and in only 4 patients did infarction occur without warning. We conclude that patients with symptomatic high-grade carotid stenosis (greater than 75%) in whom aspirin treatment failed are likely to suffer an infarct without warning as the first sign of treatment failure (P less than 0.033). We suggest that this subgroup of patients should be considered for alternative forms of therapy.

Aged↗
PubMed1990

Morphometric analysis of reticular and elastin fibers in the cerebral arteries of patients with intracranial aneurysms.

Elastin and reticular fibers were identified using standard histological strains in middle cerebral arteries taken from patients who had died from aneurysmal subarachnoid hemorrhage and control patients who did not have cerebral aneurysms. Examination of cerebral arteries from normal individuals revealed a dense network of fine reticular fibers in the arterial media that were uniformly distributed. Computerized morphometric analysis indicated that reticular fibers in the arterial media of cerebral arteries were significantly decreased in patients with aneurysms. In addition, these fibers were irregularly distributed and shortened when compared to those seen in control arteries. In both patients with aneurysms and control patients, elastin fibers were limited almost exclusively to the internal elastin lamina. No differences were observed in the appearance or content of elastin fibers in control patients and patients with aneurysm. Although other explanations cannot be excluded, these observations are consistent with the hypothesis that "intrinsic" abnormalities in the walls of cerebral arteries lead to conditions that favor the formation and rupture of cerebral aneurysms.

Aged↗
PubMed1990

Anti-inflammatory agents and cerebral vasospasm.

Delayed cerebral ischemia ascribed to vasospasm remains the largest source of morbidity and mortality today in patients who survive the initial effects of an aneurysmal subarachnoid hemorrhage. Although the cause or causes of vasospasm remain unknown, mounting evidence links its occurrence to the inflammatory response that occurs following subarachnoid hemorrhage. Animal and preliminary clinical studies suggest that both steroidal and nonsteroidal anti-inflammatory agents may be of benefit following subarachnoid hemorrhage. The clinical use of these agents has largely been limited by the concern that they may produce unwanted and serious side effects. As the understanding of the biology of chronic vasospasm increases, it may be possible to design more effective and safer anti-inflammatory drugs for this use.

Anti-Inflammatory Agents↗
PubMed1989

Prevention of chronic cerebral vasospasm in dogs with ibuprofen and high-dose methylprednisolone.

Severe chronic cerebral vasospasm was produced in dog basilar arteries by two injections, 2 days apart, of autologous blood into the cisterna magna of 25 dogs. Treatment with ibuprofen (n = 8) or high-dose methylprednisolone (n = 8) after the first injection of blood prevented or reduced angiographic vasospasm. Cerebrospinal fluid concentrations of prostaglandin E2, prostaglandin F2 alpha, 6-ketoprostaglandin F1 alpha (a metabolite of prostacyclin), and thromboxane B2 (a metabolite of thromboxane A2) were measured in both treated and untreated (n = 7) dogs. In untreated dogs, the level of prostaglandin E2 increased 94-fold by Day 8 after the first injection of blood and was strongly and positively correlated with the degree of angiographic vasospasm. Treatment with ibuprofen and high-dose methylprednisolone prevented or significantly reduced this increase in prostaglandin E2 concentration. Smaller increases in cerebrospinal fluid concentrations of thromboxane B2 and 6-ketoprostaglandin F1 alpha occurred after experimental subarachnoid hemorrhage; the magnitude of these increases was also reduced by ibuprofen or high-dose methylprednisolone treatment. In contrast, prostaglandin F2 alpha levels were not significantly altered during the study. These data show that enhanced prostaglandin E2 synthesis occurs during experimental subarachnoid hemorrhage, and the by-products generated in its synthesis may play a role in the pathogenesis of cerebral vasospasm.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

Profound hypothermia and circulatory arrest for aneurysm surgery. Case report.

Direct surgical repair of technically difficult or otherwise inoperable vascular lesions of the brain may become possible or safer using profound hypothermia and circulatory arrest. Most surgeons who use this technique establish extracorporeal circulation by cannulating the femoral vessels. To avoid difficulties associated with this closed chest method, a method was devised to establish extracorporeal circulation, profound hypothermia, and circulatory arrest by direct cannulation of the right atrium and aorta through the chest. This technique is described in a patient whose otherwise inoperable vertebral artery aneurysm was successfully treated. This approach is simple and offers several advantages over the closed chest method.

Adult↗
PubMed1989

Vascular malformations of the brain stem.

Vascular malformations of the brain stem are unusual lesions that may pose a diagnostic and therapeutic challenge. Seven patients with vascular malformations involving the brain stem were evaluated; six were treated surgically, with complete obliteration of the lesion in five patients. In five patients symptoms developed only after a hemorrhage had occurred, and three of these suffered a rebleed before appropriate treatment was given. Angiography failed to demonstrate lesions in three cases, which did not appear to protect from repeat hemorrhage since two of the three rebled. There were no operative deaths, and no patients were made permanently worse after surgery. Useful recovery occurred commonly after appropriate treatment and appeared to be possible even in patients who had suffered a catastrophic neurological deficit at the time of presentation. These data indicate that surgical removal of the lesion may be warranted in some patients with symptomatic brain-stem vascular malformation.

Adolescent↗
PubMed1988

Intraventricular cryptococcal granuloma. Report of two cases.

Infection by Cryptococcus neoformans, a budding nonmycelial yeast, involves the central nervous system in 70% of patients at the time of diagnosis. Meningitis and meningoencephalitis are common manifestations of infection; solid granulomas occur but are unusual, and intraventricular granulomas are distinctly rare. Two cases of intraventricular cryptococcal granuloma are reported. The diagnosis and treatment of mass lesions due to cryptococcal infection are discussed, with special reference to intraventricular granulomas.

Brain Diseases↗
PubMed1988

Early versus late intracranial aneurysm surgery in subarachnoid hemorrhage.

The management results in 244 patients admitted to one institution within 3 days of aneurysmal subarachnoid hemorrhage (SAH) from January, 1979, to December, 1985, were analyzed with respect to the timing of surgical intervention. Twenty-six patients died prior to surgery. Patients surviving to surgery were divided into three groups according to the interval between preadmission SAH and surgery: 0 to 3 days (85 cases), 4 to 9 days (83 cases), and 10 or more days (50 cases). Of the patients who were categorized neurologically into Botterell Grades 1 and 2 (Hunt and Hess Grades I to III) on admission, 87% had an excellent or good result on follow-up evaluation. Patients undergoing surgery 0 to 3 days after SAH had a statistically significant increase in the incidence of postoperative ischemic symptoms (p less than 0.005), which was balanced by similar complications preoperatively in the 10-day post-SAH surgical group. Most rebleeds occurred before admission but delaying surgery did increase the risk of rebleeding in the hospital (p less than 0.0005). Management morbidity and mortality occurred primarily as a direct result of a severe initial hemorrhage; thus, the measured benefits of early surgery were less than might have been predicted.

Adolescent↗
PubMed1987

Preliminary report: effects of high dose methylprednisolone on delayed cerebral ischemia in patients at high risk for vasospasm after aneurysmal subarachnoid hemorrhage.

Mounting evidence suggests that chronic cerebral vasospasm may be linked to the inflammatory response that follows subarachnoid hemorrhage. Twenty-one patients judged to be at high risk for vasospasm because of either poor admitting grade or a large amount of subarachnoid blood shown by computed tomography were treated with a course of high dose methylprednisolone, and management results were compared to those of a cohort of contemporary control patients matched for grade, number of hemorrhages, time from hemorrhage to admission, time from hemorrhage to operation, aneurysm location, age, and sex. Patients treated with high dose methylprednisolone were twice as likely to have an excellent result and half as likely to die as those who were not treated. The incidence and severity of delayed cerebral ischemia were reduced in treated patients when compared to control patients. None of the treated patients developed a serious side effect that could be attributed to steroid treatment. These findings are consistent with the conclusion that chronic vasospasm is an inflammatory vasculopathy and suggest that early treatment with high dose methylprednisolone may benefit this high risk group of patients.

Adult↗
PubMed1987

Solitary eosinophilic granuloma of the frontal lobe.

Solitary intracranial eosinophilic granulomas are rare and most frequently involve the hypothalamus. We report an unusual case of solitary eosinophilic granuloma of the frontal lobe in a patient without evidence of systemic disease. Previously reported cases of solitary intracranial nonhypothalamic lesions are reviewed, and the clinical, radiographic, and histological features of this case are discussed.

Adult↗
PubMed1984

Cerebral vasospasm after subarachnoid hemorrhage.

Chronic cerebral vasospasm remains the most important cause of subsequent morbidity in patients who survive the first 48 to 72 hours after a subarachnoid hemorrhage. Prolonged arterial narrowing compromises cerebral hemodynamics and results in cerebral ischemia. Among patients in whom symptomatic chronic cerebral vasospasm develops, almost half die or have a serious residual neurologic deficit. Present evidence indicates that sustained vessel narrowing results from structural changes within the arterial wall rather than from active contraction of vascular smooth muscle. The mechanism (or mechanisms) responsible for these changes is unknown, but damage from prolonged active arterial contraction, depression of vessel wall respiration, and an inflammatory response have all been proposed as explanations. Despite more than 30 years of intensive study, an effective treatment program for chronic cerebral vasospasm remains elusive. Recent therapeutic trials, however, based on efforts to interrupt the mechanisms responsible for these structural changes hold some promise.

Animals↗
PubMed1984

Measurement of prostaglandins in the cerebrospinal fluid in cat, dog, and man.

Prostaglandins are involved in the modulation of various central functions (neurotransmitters and hypothalamic hormone release, thermoregulation, cerebrovascular tone) and their levels increase in pathological situations [subarachnoid hemorrhage (SAH), stroke, convulsive disorders, etc.]. This study, using sensitive and specific antibodies, examined levels of four eicosanoids, prostaglandins E2 and F2 alpha (PGE2, PGF2 alpha); and the metabolites of PGI2, 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), and of thromboxane A2, thromboxane B2 (TxB2), in the cerebrospinal fluid (CSF) obtained atraumatically from three species (human, canine, and feline). An assessment of the methodologic procedures (extraction and radioimmunoassay) was carried out. Human lumbar cerebrospinal fluid was shown to contain PGF2 alpha (15-44 pg/ml), 6-keto-PGF1 alpha (undetectable to 39 pg/ml), and TxB2 (undetectable to 28 pg/ml), whereas PGE2 was undetectable (less than 18 pg) in all cases. In both animals species the eicosanoid concentrations were 3- to 30-fold higher than humans for every prostaglandin examined. Although the prostaglandin profile for a given species remained constant (cat, PGE2:6-keto-PGF1 alpha:TxB2:PGF2 alpha; dog, TxB2:PGE2:6-keto-PGF1 alpha:PGF2 alpha), the absolute levels were found to be lower in the pentobarbital-anesthetized animals than in conscious cats. The correspondence of the prostaglandin profiles found in cerebrospinal fluid with the profiles reported in the literature in brain homogenates for the same species supports the hypothesis that cerebrospinal fluid levels of prostaglandins reflect the relative rates of synthesis in neural tissue.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Response of chronic experimental cerebral vasospasm to methylprednisolone and dexamethasone.

The authors have previously demonstrated that high-dose methylprednisolone (30 mg/kg intravenously every 8 hours) prevents severe chronic vasospasm in dogs. In the present study, lesser doses of methylprednisolone (15 mg/kg intravenously every 8 hours) and dexamethasone (0.1 mg/kg intravenously every 8 hours), although better than no treatment at all, were significantly less effective than the higher dose of methylprednisolone. These data suggest that methylprednisolone can prevent chronic experimental vasospasm from occurring only when given in high doses (30 mg/kg).

Animals↗
PubMed1983

Prevention of chronic experimental cerebral vasospasm with ibuprofen and high-dose methylprednisolone.

Severe chronic cerebral vasospasm was reliably induced in dogs by two injections, 2 days apart, of autologous blood into the cisterna magna. Treatment with ibuprofen or high-dose methylprednisolone after the first injection prevented or reduced vasospasm. Both drugs reduced meningismus and accelerated the rate of neurological recovery. Compared with specimens from normal dogs, rings of basilar arteries obtained from untreated dogs contracted weakly in response to 5-hydroxytryptamine, prostaglandin F2 alpha, potassium chloride, and barium chloride. Rings of arteries from dogs who received ibuprofen or methylprednisolone contracted more strongly. Electron micrographs of basilar arteries from untreated dogs showed degeneration of smooth muscle, whereas those from treated dogs did not. Thus, what is termed "chronic cerebral vasospasm" probably represents a structural derangement of the blood vessel wall leading to its narrowing, rather than a sustained contraction of the vascular smooth muscle. Administration of high-dose methylprednisolone and ibuprofen can prevent its occurrence.

Animals↗
PubMed1978

Enhancement of UDPgalactose: glycoprotein galactosyltransferase in cultured human skin fibroblasts by cationic polypeptides.

UDPgalactose : glycoprotein galactosyltransferase in normal human skin fibroblast homogenates has been assayed using ovalbumin as an acceptor. The activity in the homogenate fraction sedimenting between 51 300 X g and 105 000 X g was enhanced by the addition of a number of catonic polypeptides of L-configuration but not by those of D-configuration. In contrast to the enhancing effect of poly(L-lysine), poly(L-glutamic acid) inhibited the activity. Poly(D-glutamic acid) had no effect. Cationic or anionic amino acid derivatives, spermine or spermidine had no effect on activity. The enhancement of transferase activity by poly(L-arginine) is probably due to an increase in V for UDPgalactose and ovalbumin. The implication of these results for the regulation of glycoprotein synthesis in cultivated skin fibroblasts and for the pathogenesis of cystic fibrosis is discussed.

Cells, Cultured↗