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Biomedical subjects

B I Tranmer

Publications and source records attributed to B I Tranmer.

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

Epstein-Barr virus-associated primary B-cell lymphoproliferative disorder of the cerebellum in an immune competent man.

BACKGROUND: The role of the Epstein-Barr virus (EBV) in lymphoproliferative lesions has been widely accepted. Most of these lesions occur in patients who have deficiencies in their immune status. Lymphomatoid granulomatosis (LG) is a lymphoproliferative disorder originally characterized as an angiocentric, necrotizing, pleomorphic infiltrate of mononuclear cells. The etiology of LG is unknown. It was originally hypothesized that LG may represent an unusual lymphoid response to an infective organism, possibly EBV. METHODS: Tissues from a previously healthy 60-year-old, healthy white man with primary cerebellar lymphomatoid granulomatosis were examined for the presence of EBV by nucleic acid hybridization. RESULTS: The original LG lesion was a polyclonal B-cell proliferation that contained detectable amounts of EBV. Peripheral blood leukocytes were negative for EBV by the same assay. After an 18-month remission, a tumor reappeared near the site of the primary lesion, which had the histologic appearance of a lymphoma. The cells showed restricted clonality and contained a similar amount of EBV-related DNA as the original lesion. Peripheral blood leukocytes at the time of recurrence were negative for EBV. The patient died approximately 2 months after the recurrent tumor was detected. CONCLUSIONS: This case demonstrated the development of a primary cerebellar B-cell lymphoproliferative disorder, histologically identical to lymphomatoid granulomatosis, that transformed into a lymphoma. The original tumor and the subsequent lymphoma contained, on average, several copies of EBV-related DNA per cell. Despite an extensive survey of the patient, no immune deficit was detected. Interpretation of the literature with the results of this case suggest that this instance of primary cerebellar LG arose as a consequence of an unusual EBV-associated B-cell lymphoproliferation. It is suggested that EBV may be a significant factor in the initiation of the abnormal proliferations of T-cells or B-cells reported in this disorder.

B-Lymphocytes↗
PubMed1992

Loss of cerebral regulation during cardiac output variations in focal cerebral ischemia.

Focal cerebral ischemia was induced in anesthetized macaque monkeys by unilateral middle cerebral artery occlusion. The effect of blood volume expansion by a colloid agent and subsequent exsanguination to baseline cardiac output (CO) on local cerebral blood flow (CBF) was measured by the hydrogen clearance technique in both ischemic and nonischemic brain regions. Cardiac output was increased to maximum levels (159% +/- 92%, mean +/- standard error of the mean) by blood volume expansion with the colloid agent hetastarch, and was then reduced a similar amount (166% +/- 82%) by exsanguination during the ischemic period. Local CBF in ischemic brain regions varied directly with CO, with a correlation coefficient of 0.89 (% change CBF/% change CO), while CBF in nonischemic brain was not affected by upward or downward manipulations of CO. The difference in these responses between ischemic and nonischemic brain was highly significant (p less than 0.001). The results of this study show a profound loss of regulatory control in ischemic brain in response to alterations in CO, thereby suggesting that blood volume variations may cause significant changes in the intensity of ischemia. It is proposed that CO monitoring and manipulation may be vital for optimum care of patients with acute cerebral ischemia.

Animals↗
PubMed1991

Haemodynamic considerations in the management of patients with subarachnoid haemorrhage.

Cerebral vasospasm occurs, following subarachnoid haemorrhage, in the majority of patients and is accompanied by cerebral ischaemia in 30%. The objectives of this article are to review (1) the effects of subarachnoid haemorrhage and vasospasm on cerebral blood flow (CBF); (2) the effects of induced hypotension and hypocapnia on CBF in these patients; (3) current therapy for cerebral ischaemia from vasospasm. The medical literature was searched using Index Medicus; for the period 1983-90 this search was done on a computer with the CD-ROM version of Index Medicus, Silver Platter. Papers were selected on the basis of validity and applicability to clinical practice; animal studies are included when human data is lacking. Cerebral vasospasm may decrease cerebral blood flow, disturb autoregulation and place the patient at risk for delayed cerebral ischaemia. Intraoperative induced hypotension and hypocapnia can decrease CBF further, although effects of either on outcome have not been evaluated. Calcium antagonists are effective for both the prevention and the treatment of delayed cerebral ischaemia. Of the mechanical treatments, systemic-arterial hypertension has the firmest scientific foundation, although this is frequently combined with haemodilution and blood volume expansion. There is a need for randomized clinical trials to assess the efficacy of these latter treatments.

Brain Ischemia↗
PubMed1991

Stabilization of traumatic atlanto-occipital dislocation. Case report.

Traumatic atlanto-occipital dislocation is most often fatal. Consequently, there are only scattered case reports of patients surviving this injury, and treatment modalities are anecdotal and varied. The case of an 18-year-old woman who suffered an anterior atlanto-occipital dislocation as the result of a motor-vehicle accident is presented. Rigid posterior fixation and complete reduction of the dislocation were achieved using an anatomically contoured steel loop secured to the occiput and cervical vertebrae. The addition of cancellous bone to the graft afforded long-term stability. This operative treatment provided anatomical realignment of the dislocation and allowed early mobilization of the patient with the use of aggressive rehabilitation. Previously reported cases of patients surviving anterior atlanto-occipital dislocation are reviewed. The use of cervical traction, halo bracing, and operative stabilization is discussed.

Accidents, Traffic↗
PubMed1990

Effect of Fluosol-DA and hetastarch on local cerebral blood flow, cortical O2 availability and computerized EEG data during cerebral ischaemia.

This study was designed to assess the effects of volume expansion with Fluosol-DA and hetastarch on local cerebral blood flow (CBF), cortical O2 availability (O2a) and computerized EEG power data during cerebral ischaemia in a primate stroke model. Focal cerebral ischaemia was produced in 20 anaesthetized Macaca monkeys by right unilateral middle cerebral artery (MCA) occlusion by the transorbital technique. Following occlusion of the right MCA, monkeys were randomized into one of the following treatment groups: Group A--Fluosol-DA 15 ml kg-1 i.v. + 40% O2; Group B--Fluosol-DA 15 ml kg-1 i.v. + 100% O2; Group C--hetastarch 30 ml kg-1 i.v. + 40% O2; Group D--hetastarch 30 ml kg-1 i.v. + 100% O2. In Group A, local CBF increased and EEG power data improved while O2a showed no change in the right MCA territory. In Group B, local CBF increased from 84% (P less than 0.001), O2a improved significantly, and EEG power data showed significant improvement in the right hemisphere. Cardiac output did not change during the Fluosol-DA infusions. In Groups C and D, local CBF increased significantly, O2a did not change, and EEG power data improved significantly in the right hemisphere. Cardiac output also increased significantly during the hetastarch infusions. These results show that Fluosol-DA and hetastarch improve local CBF and EEG power data in ischaemic brain. Only the Fluosol-DA + 100% O2 increased the O2a in the ischaemic brain. We conclude that the benefits with Fluosol-DA are due to its ability to increase O2 delivery to ischaemic brain.

Animals↗
PubMed1990

Increased cerebral blood flow in idiopathic pseudotumour cerebri.

Cerebral blood flow was studied in nine patients with idiopathic pseudotumour and one patient with cortical vein thrombosis in Denver, Colorado using the 133Xe inhalation method. Globally elevated blood flows were found in all of the idiopathic pseudotumour patients averaging 149% of control values generated in the same setting. The patient with the cortical vein thrombosis demonstrated normal global flows. Possible pathophysiological mechanisms for these findings are discussed.

Adult↗
PubMed1989

An unusual case of temporal encephalocele.

An unusual case of temporal encephalocele is presented in this report. A large temporal mass was detected prenatally by ultrasound and following delivery by caesarian section. It was determined to be a large temporal encephalocele with extensive invasion into the subtemporal, facial and cervical regions. This case is presented because of the unique pathology of this congenital malformation and the extensive surgery that was required. The management and the clinical and radiological features are discussed.

Encephalocele↗
PubMed1989

Intra-aortic balloon counterpulsation: a treatment for ischaemic stroke?

Intra-aortic balloon counterpulsation (IABC) augments cardiac output (CO) and pulse pressure (PP) allowing patients with low output heart failure to be supported for a period of time. Augmentation of CO and PP may also be beneficial to the patient with acute cerebral ischaemia. In this paper we investigated the possibility of using IABC to increase local cerebral blood flow (CBF) in ischaemic brain. In 12 anaesthetized mongrel dogs, a canine stroke model was produced by occluding the left internal carotid and middle cerebral arteries with aneurysm clips. Six dogs were then treated with IABC for 2 h, and 6 other dogs acted as controls (no IABC). Haemodynamic data were measured continuously and CBF (microsphere technique) and CO measurements were performed pre- and post-occlusion, and then twice during the treatment period. In the IABC-treated animals, PP increased from 32 +/- 5.9 to 39 +/- 7.8 mmHg (p less than 0.01) but CO and local CBF in the ischaemic brain did not change significantly during IABC. However, in 4 dogs with significant increases in CO due to IABC [1.7 +/- 0.3 to 2.8 +/- 0.7 l/min (p less than 0.05)], local CBF in ischaemic brain also increased significantly from 22 +/- 12 to 26 +/- 11 cc/100 g/min (p less than 0.05). In the control animals, CO and local CBF did not change significantly during the observation period. These data suggest that augmentation of CO and PP by IABC results in an increase in local CBF in ischaemic brain. IABC may be an effective treatment for ischaemic stroke in those patients with compromised cardiac performance whose cardiac output and pulse pressure can be augmented by IABC.

Animals↗
PubMed1989

Effects of crystalloid and colloid infusions on intracranial pressure and computerized electroencephalographic data in dogs with vasogenic brain edema.

This experiment was designed to study the effects of intravascular volume expansion with crystalloid and colloid agents on intracranial pressure (ICP) and computerized electroencephalographic (EEG) data in dogs with cerebral vasogenic edema. A liquid nitrogen cold lesion was produced in the right parietal lobes of 30 anesthetized mongrel dogs. ICP data from an intraventricular catheter, hemodynamic data, and EEG power data were recorded continuously during the course of the experiment. Six hours after creation of the liquid nitrogen cold lesion, each dog was infused with one of the following treatments: 1) no treatment (control); 2) 5% dextrose in water (D5W) (30 ml/kg/h); 3) 0.9% NaCl (30 ml/kg/h); 4) hetastarch (10 ml/kg/h); and 5) hetastarch (30 ml/kg/h). The animals were treated for 2 hours, killed, and the brains examined and measured for water content. During the D5W infusion, ICP increased significantly (141%) but the EEG power data did not change. During the normal saline infusion, ICP increased significantly (91%) and the EEG power data showed marked deterioration. Both hetastarch infusions produced no change in ICP and demonstrated an improvement in the EEG power data (P less than 0.001). These data suggest that crystalloid infusions may have profound deleterious effects in the presence of brain edema, but colloids do not, and should be considered in the fluid management of patients with cerebral edema.

Animals↗
PubMed1988

Colloidal volume expansion during acute cerebral ischaemia: assessed by local cerebral blood flow and computerized power ratio index.

Colloidal volume expansion during acute cerebral ischaemia was assessed by local cerebral blood flow (CBF) and the power ratio index (PRI) in 8 anaesthetized Macaque monkeys. Focal cerebral ischaemia was produced by right middle cerebral artery occlusion. The animals were then volume expanded (to maximum cardiac output) with 6% hetastarch and then exsanguinated to baseline cardiac output. During volume expansion, local CBF in the ischaemic hemisphere increased from 25 +/- 12 to 39 +/- 23 cc/100 g/min (p less than 0.01) and during exsanguination decreased to 32 +/- 18 cc/100 g/min. Local CBF did not change significantly in the nonischaemic hemisphere. EEG power data, as assessed by PRI [(delta + theta power/alpha + beta power) x 100] changed significantly during blood volume manipulation. The mean PRI value in the right hemisphere deteriorated by increasing from 65 +/- 22 to 94 +/- 25 (p less than 0.01) following vessel occlusion but improved by decreasing to 81 +/- 23 (p less than 0.05) following volume expansion. Following exsanguination, the PRI value increased to 87 +/- 21. These data demonstrate the benefits of volume expansion during acute cerebral ischaemia. Changes in local CBF were consistently associated with changes in the PRI maps and values.

Animals↗
PubMed1988

Thrombosed arteriovenous malformations: a type of occult vascular malformation. Magnetic resonance imaging and histopathological correlations.

Thrombosed arteriovenous malformations (AVMs) are the predominant type of occult vascular malformation and do not seem to differ significantly in clinical or radiographic presentation from other types of occult vascular malformations. Thrombosed AVMs and occult vascular malformations occasionally present with symptoms secondary to subacute or occult hemorrhage that requires operation. The histopathology of thrombosed AVMs and occult vascular malformations does not seem to have prognostic significance. Five patients with histologically verified thrombosed AVMs are reported. Two patients had previous incomplete resection of histologically proven thrombosed AVMs and presented with recurrence and bleeding. Two patients presented with seizures and headaches, and one patient presented with hemiparesis and headache. All histology specimens had evidence of hemorrhage. The pathological findings of these lesions seem variable; two specimens contained a mixture of cavernous angioma and AVM. Two previously resected lesions had been defined histologically as thrombosed AVMs. Successful excision of the lesions was accomplished in four patients, and one patient had stereotactic biopsy. The magnetic resonance imaging characteristics of lesions seem to add a degree of specificity over computed tomography and angiography. We have found that the literature poorly describes the natural history and histology of these lesions. Conservative management for seizures and headaches due to thrombosed AVMs may not be warranted because of a propensity for hemorrhage and recurrence.

Adult↗
PubMed1987

Sleep apnea following percutaneous cervical cordotomy.

Sleep apnea (Ondine's Curse) is an uncommon but potentially fatal complication of percutaneous cervical cordotomy. The authors have had the opportunity to review the case histories of 6 patients who have died of sleep apnea following this procedure. In a series of 112 patients, 144 cervical percutaneous cordotomies were performed from 1977 to 1985--80 unilateral cordotomies and 32 staged bilateral cordotomies. Six (5%) patients died as the result of sleep apnea. Five patients (16%) died following bilateral cordotomy and one (1%) patient with pulmonary disease died following unilateral cordotomy. The clinical data of these 6 patients are presented and unique spinal cord pathology is described in this report. The pathophysiology of the sleep apnea syndrome is also discussed.

Aged↗
PubMed1986

Blood volume expansion with hetastarch in acute ischaemic stroke: the effects on local cerebral blood flow and computer mapped EEG.

Focal cerebral ischaemia was induced in seven anaesthetized monkeys by unilateral middle cerebral artery (MCA) occlusion. Local cerebral blood flow (CBF) and computer mapped EEG (CME) changes were then studied as blood volume and cardiac output (CO) were varied. CO was increased by colloidal volume expansion and decreased by exsanguination. Local CBF fell to 24 +/- 9% of control values in ischaemic areas following MCA occlusion and increased to 43 +/- 19% of control values (p less than 0.01) when CO was increased by 130 +/- 70% with colloid infusion. Local CBF to nonischaemic regions was not altered significantly by blood volume expansion. Exsanguination led to return of CO to control levels and was associated with reduction of local CBF in ischaemic regions to 24 +/- 12% of control values (p less than 0.05). CME showed bifrontal or ipsilateral slow wave foci (delta) following MCA occlusion. Blood volume expansion brought about a marked reduction of this slow wave activity and exsanguination led to recurrence of the slow wave foci. This data demonstrated that colloidal blood volume expansion induced an increase in local CBF and improved neuroelectric status of ischaemic brain following MCA occlusion. It was also shown that a reduction of blood volume and cardiac output resulted in a reduction in local CBF and a worsening of neuroelectric status in ischaemic areas. This study supports the contention that blood volume and cardiac output maintenance is extremely important in the management of acute ischaemic stroke.

Animals↗
PubMed1986

Acute middle cerebral artery occlusion: experience with volume expansion therapy.

Five consecutive patients with acute neurological deficits after middle cerebral artery (MCA) occlusion were given emergency treatment with colloidal volume expansion. In each case, the diagnosis was confirmed promptly by computed tomography and cerebral angiography. Aggressive volume expansion therapy was started 2 to 18 hours (mean, 11 hr) after the onset of the neurological deficit. The mean colloidal volume used was 920 ml/day for an average of 4 days. During volume expansion, the mean cardiac output increased 57% from 4.6 +/- 0.6 to 7.2 +/- 1.9 litres/min (P less than 0.05). The mean hematocrit decreased 19% from 46 +/- 3% to 37 +/- 4% (P less than 0.01). The mean arterial blood pressure remained stable, and the pulmonary artery wedge pressure was maintained at less than 15 mm Hg. Three patients improved dramatically with volume expansion therapy and have returned to their previous life-styles. Two patients made partial recoveries and manage at home with nursing care. The three patients who improved dramatically were young (aged less than 34) and, when compared to the older patients, they had greater increases in cardiac output (67% vs. 19%). No major complications or deaths were attributed to the volume expansion therapy. We propose that intravascular volume expansion and its concomitant augmentation of the cardiovascular dynamics may be effective in the treatment of acute neurological deficits after acute MCA occlusion.

Acute Disease↗
PubMed1986

Perineurioma: a benign peripheral nerve tumor.

A unique benign peripheral nerve tumor, called a perineurioma, is described in this report. Light and electron microscopy and immunohistochemistry indicate that this tumor was derived from the perineurial cell. We discuss the ultrastructure, histogenesis, and management of this neoplasm.

Adult↗
PubMed1986

Pulsatile versus nonpulsatile blood flow in the treatment of acute cerebral ischemia.

The effects of pulsatile and nonpulsatile perfusion on local cerebral blood flow (CBF) and on computerized mapping (CME) of electroencephalograms (EEG) in nonischemic and ischemic brain were studied using a canine stroke model. Nine anesthetized mongrel dogs were placed on normothermic right atrial-femoral artery cardiopulmonary bypass at a flow of 100 ml/kg/minute. Local CBF measurements and CME data were collected during nonpulsatile perfusion and maximal pulsatile perfusion. The stroke model was then produced, and local CBF measurements and CME data were again collected during nonpulsatile and pulsatile perfusion. In the nonischemic brain, local CBF increased 19%, from 32 +/- 10 to 38 +/- 11 ml/100 g/minute (P less than 0.01), when perfusion was changed from nonpulsatile flow (pulse pressure less than 4mm Hg) to pulsatile flow (pulse pressure 39 +/- 11 mm Hg). In the ischemic brain, local CBF increased 55%, from 11 +/- 5 to 17 +/- 7 ml/100 g/minute (P less than 0.01), when perfusion was changed from nonpulsatile (pulse pressure less than 3 mm Hg) to pulsatile (pulse pressure 36 +/- 7) flow. EEG power data, expressed as a power ratio index (PRI = low frequency power/high frequency power), improved significantly, from 110 +/- 33 to 101 +/- 41 (P less than 0.01) with pulsatile perfusion. These data demonstrate the importance of pulsatile blood flow in ischemic brain.

Acute Disease↗