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Biomedical subjects

W A Hall

Publications and source records attributed to W A Hall.

At least 91 records · Page 5Linked to original sources
PubMed1993

Targeted brain biopsy: a comparison of freehand computed tomography-guided and stereotactic techniques.

With computed tomography (CT) and magnetic resonance imaging stereotactic systems, biopsies of intracranial lesions can be made with safety and ease. Before the development of this technique, neurosurgeons often performed freehand brain biopsies under CT guidance. While stereotactic biopsy is the procedure of choice for small, deep lesions, few studies have compared the morbidity, mortality, and efficacy in obtaining a diagnosis associated with these two techniques for superficial lesions. A total of 167 consecutive CT-guided or stereotactic brain biopsies were performed in 154 patients. Fourteen of the stereotactic and 12 of the CT-guided biopsies were of deep lesions and were excluded from analysis. The results of 75 freehand CT-guided biopsies of superficial lesions in 69 patients were compared with those of 66 stereotactic biopsies (34 CT-guided and 32 MRI-guided) performed with the Brown-Roberts-Wells stereotactic system in 60 patients. Twenty-five of the lesions in the stereotactic biopsy group measured < or = 2 cm, as compared with 13 of those in the freehand CT-guided biopsy group. There were no biopsy-related deaths among the patients who underwent freehand CT-guided biopsy and one death among those who underwent stereotactic biopsy (1.5%). Freehand CT-guided biopsy was associated with 5% morbidity, compared with 6% morbidity for stereotactic biopsy. Seven CT-guided needle biopsies (9%) and 12 stereotactic biopsies (18%) were nondiagnostic. Statistical analysis showed no significant difference between morbidity and mortality in the two groups, but the rate of diagnostic failure was significant (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Rapid detection of transferrin receptor expression on glioma cell lines by using magnetic microspheres.

A rapid method for detecting the presence of transferrin receptors (TR) on human glioblastoma-derived cell lines is presented. The development of new treatment modalities, such as immunotoxins for central nervous system cancer, requires the identification of appropriate surface antigens on tumor cells. Seven established human glioblastoma-derived cell lines were assayed for the presence of TR with antibody-coated magnetic microspheres (immunobeads). The immunobeads bound to glioblastoma cells in the presence of human anti-TR monoclonal antibodies to a significantly greater degree than to control cell lines (P < 0.0001). The expression of TR was confirmed by standard immunocytochemical techniques. A 9L rat gliosarcoma cell line was used as a nonhuman control and did not demonstrate TR expression by either the immunobead assay or immunocytochemistry. This assay represents a simple, sensitive way to detect TR expression on malignant cells, which may be useful for the identification of other cell surface antigens that can be exploited by targeted therapies.

Brain Neoplasms↗
PubMed1993

Development and early testing of the Role Enactment Questionnaire.

The Role Enactment Questionnaire was developed to measure role intensity and role disparity experienced by the parents of young children. These two factors have been described as antecedents to role strain. The instrument subsumes three 5-point Likert scales that represent two dimensions and four roles. Scale development included: content validation and initial psychometric testing with 92 parents to conduct a reliability analysis. The final version of the Role Enactment Questionnaire consisted of 126 items. Cronbach's alphas were 0.90 for the disparity dimension and 0.89 for the intensity dimension. Test-retest reliabilities (r) based on the responses obtained from 78 of the parents were 0.73 and 0.80 for role disparity and role intensity, respectively.

Adaptation, Psychological↗
PubMed1993

Infectious lesions of the brain stem.

Infectious lesions of the brain stem are rare and include primarily abscess and encephalitis. The most common etiologic agents for abscess formation are Streptococcus sp., Staphylococcus sp., and M. tuberculosis. Encephalitis is associated most often with L. monocytogenes and herpes simplex virus infection. Classical brain stem syndromes are uncommon with brain stem infections, and CSF obstruction can be seen with neurocysticercosis. The diagnosis of these lesions has been greatly aided by CT and MR imaging. Microsurgery and stereotaxis are both appropriate techniques for the treatment of brain stem abscess that establish a diagnosis, identify the causative agent, and relieve mass effect on important neural structures. Symptoms of hydrocephalus should be treated with temporary or permanent CSF diversion. Viral involvement of the brain stem is usually self-limited, and improved antimicrobial therapy has contributed to a decrease in the morbidity and mortality of bacterial and parasitic infections. Although once believed to be uniformly fatal, infections of the brain stem have now been successfully treated for more than a decade.

Brain Abscess↗
PubMed1992

Comparison of the experience of women and men in dual-earner families following the birth of their first infant.

This paper describes an extension of the concept of "redefining roles" developed from an initial study that described the experience of eight women in dual-earner families following the birth of their first infant. A second study used redefining roles as a springboard and described the experience of ten men. Although constant comparative analysis generated a core variable in both studies best described as "redefining roles," the two groups redefined their roles somewhat differently. When the women redefined their roles, they took on multiple roles, experienced role strain, and reduced role strain. The men monitored and limited role strain. The implications for nursing practice are outlined.

Adult↗
PubMed1992

Metastatic carcinoid tumor to the orbit and brain.

Carcinoid tumors constitute an uncommon source of metastatic lesions to the brain. We report the case of a 63-year-old man who initially sought treatment for proptosis 15 years before coming to our attention with a metastatic intracerebral left parietal carcinoid. The pathological features of the exenterated orbital mass were interpreted as undifferentiated carcinoma, and a lesion of the left lower lobe of the lung that had been removed 6 years earlier had been reported as metastatic malignant melanoma. The long duration between the initial diagnosis and the onset of neurological symptoms brought into question the original diagnosis, which, in retrospect, was most consistent with metastatic carcinoid. Staining for cytokeratin, neuron-specific enolase, and synaptophysin in the absence of staining for S-100 and HMB-45 supported the revised pathological diagnosis. Metastatic intracerebral carcinoid from an unrecognized bronchogenic source is a rare event, particularly after an orbital metastasis, but should be suspected when the clinical course is inconsistent with the more common causes of metastatic disease.

Biomarkers, Tumor↗
PubMed1992

Immunotoxins and central nervous system neoplasia.

The poor prognosis associated with central nervous system (CNS) malignancy has led investigators to seek new, innovative treatment modalities. Immunotoxins, carrier molecules linked to toxic agents, combine high specificity for tumor-associated antigens with extreme potency. The rationale for both the development of these compounds and for their application to CNS neoplasia is explained. This report discusses the design and construction of immunoconjugates, using toxins that differ in their mechanism of action bound to ligands directed against various antigens. A comparison is made between the in vitro efficacy of standard chemotherapy and immunotoxins in glioblastoma- and medulloblastoma-derived cell lines. A review is included of the results of experiments in animals with leptomeningeal neoplasia, where prolongation of survival following intrathecal administration of immunotoxins has been reported. The obstacles encountered in clinical trials with other types of cancer are addressed and approaches to optimize the use of these novel agents in the context of treating malignant disease of the CNS are suggested.

Animals↗
PubMed1992

In vitro efficacy of transferrin-toxin conjugates against glioblastoma multiforme.

The cytotoxic activity of immunotoxins constructed with human diferric transferrin (Tfn) as the carrier ligand and an abrin variant Pseudomonas exotoxin A (PE) and the diphtheria toxin mutant cross-reacting material (CRM) 107 as the toxin moieties were studied in vitro. Three malignant human cell lines, the glioblastomas multiforme SNB19 and SF295 and the LOX melanoma, and a nonhuman control murine melanoma cell line B16 were assessed. The presence of transferrin receptors on the cell lines was confirmed by direct 125I-Tfn binding assays. The 50% protein synthesis inhibitory concentration (IC50) values for all cell lines demonstrated that Tfn-abrin variant and Tfn-PE had comparable potency and were both more effective than Tfn-CRM 107. Monensin, a carboxylic ionophore, potentiated the effect of Tfn-abrin variant against glioma cells approximately 35-fold with IC50 values of 4.0 x 10(-13) M and 4.7 x 10(-12) M for SNB19 and SF295, respectively. Cytotoxic activity of Tfn-abrin variant (with or without monensin) and Tfn-PE was correlated with the degree of Tfn receptor expression measured on the cell lines. The exquisite in vitro cytotoxicity of Tfn-abrin variant and Tfn-PE immunotoxins against glioma and melanoma cells warrants further in vivo evaluation and future consideration of these agents for potential clinical application against glioblastoma multiforme and leptomeningeal neoplasia.

ADP Ribose Transferases↗
PubMed1992

Infections in neurologic surgery. The intraventricular use of antibiotics.

Intraventricular antibiotic therapy appears to be a useful treatment modality in those CSF infections in which systemic therapy may fail. Consideration should be given to using this form of treatment when infecting organisms are only sensitive to antibiotics with poor penetration of the CSF (e.g., aminoglycosides and vancomycin) and for cases in which intravenous therapy has failed to sterilize the CSF, toxicity from systemic therapy precludes further increases in dosages, and shunts or other CSF hardware might be expected to reduce the efficacy of systemic therapy by providing a foreign body to harbor organisms. Shunts or reservoirs that are infected may be successfully sterilized with IVT therapy alone or in conjunction with systemic therapy, but this has a lower success rate than cases in which the shunt is removed. There is a wealth of clinical experience with IVT vancomycin and gentamicin that suggests that they are relatively safe. Until more data are available on other aminoglycosides and newer antibiotics, these two agents should be considered the antibiotics of choice for IVT therapy. In situations in which the organism is sensitive to both vancomycin and gentamicin, vancomycin should be used in view of the documented neurotoxicity seen with gentamicin. When gentamicin resistance occurs, amikacin and tobramycin are appropriate alternatives. The high risk of epilepsy with the penicillins and cephalosporins makes them less suited for IVT therapy, although the newer cephalosporins have some promise for IVT therapy. CNS fungal infections can be treated effectively with IVT amphotericin B but with a high risk of significant toxicity. Miconazole appears to be safer than amphotericin B but there is less clinical experience with this drug. Table 1 summarizes the dosages, indications, and toxicity of those antibiotics commonly used for intraventricular administration, which have been reported previously.

Anti-Bacterial Agents↗
PubMed1992

Neurosurgical infections in the compromised host.

Granulocytopenia, cellular and humoral mediated immune dysfunction are predisposing factors to the development of CNS infections in immunosuppressed patients. Brain abscess formation in the compromised host is most commonly caused by enteric bacilli, the bacterium N. asteroides, the fungus Aspergillus fumigatus, or the parasite T. gondii. Mucor and the JC virus cause invasive encephalitis in this patient population. CT and MR imaging have greatly aided in the diagnosis of intracranial lesions because of these agents. Stereotactic biopsy-aspiration for diagnosis and to relieve mass effect combined with systemic antimicrobial therapy is the treatment of choice for intracerebral abscess in the compromised host. Organ rejection and chronic immunosuppressive therapy can complicate surgical intervention in these patients. Only with a high index of suspicion, an aggressive approach to diagnosis, and rapid vigorous therapy may we hope to alter the clinical course in this difficult group of patients.

Brain Abscess↗
PubMed1991

Central nervous system germinomas. A review.

The germinoma represents a less malignant form of germ cell tumor. Depending on the individual's age, this neoplasm constitutes approximately 0.1% to 3.4% of all intracranial tumors. The embryologic origin remains a mystery; however, current theories implicate an aberration in primordial germ cell migration. Clinical presentation depends on tumor location and may involve endocrine, hypothalamic, visual, and cognitive dysfunction. In evaluating midline intracerebral masses, it is imperative that one be aware of the various radiologic appearances, endocrinologic changes, and chemical markers that help to distinguish germinomas from other neoplasms that appear in the pineal, suprasellar, and periventricular regions. Only through the careful evaluation of all available studies can the physician institute appropriate therapies such as biopsy, radiation, and chemotherapy. This article focuses on the epidemiology, embryology, clinical presentation, means of diagnosis, treatment, and outcome of this rare neoplasm.

Brain Neoplasms↗
PubMed1990

Subarachnoid-pleural and subarachnoid-mediastinal fistulae.

Subarachnoid-pleural fistula and subarachnoid-mediastinal fistula are rare complications of chest trauma. One case each of subarachnoid-mediastinal fistula and subarachnoid-pleural fistula is described. Both patients were young children who suffered severe longitudinal distraction injuries to their thoracic spine and exhibited complete cord transection without radiographic evidence of vertebral column injury. Progressive mediastinal widening and enlarging pleural effusion in the absence of angiographic evidence of aortic injury suggested the diagnosis of an intrathoracic cerebrospinal fluid fistula. Myelograms identified the site of spinal cord rupture and cerebrospinal fluid leakage. The diagnosis, management, and outcome of these rare fistulae are discussed.

Brain Diseases↗
PubMed1990

Epidermal growth factor receptors on ependymomas and other brain tumors.

Epidermal growth factor receptor (EGFR) and transferrin receptor levels were determined in 14 intracranial neoplasms (four glioblastomas multiforme, four medulloblastomas, four ependymomas, one cerebellar astrocytoma, and one acoustic neurinoma) and in four samples of "normal" brain tissue. A competitive radioreceptor assay with 125I-epidermal growth factor and 125I-transferrin was performed using the primitive neuroectodermal tumor-derived TE-671 tissue-culture cell line as a standard. Epidermal growth factor receptors were present on TE-671 cells, all four ependymomas, and two of the four glioblastomas multiforme. The number of EGFR's per cell for ependymomas were estimated to range from 1000 to 6000. Transferrin receptors were detected on TE-671 cells, two of the four medulloblastomas, and one of the four glioblastomas multiforme. A cell surface binding assay, performed directly on the rat ependymal cell monolayer, was also analyzed. The identification of EGFR's on ependymomas and TR's on medulloblastomas suggests that malignant central nervous system tumors that spread by cerebrospinal fluid pathways may be treatable by intrathecal antibody-toxin conjugates. The presence of EGFR's on all of the ependymomas may reflect a role of the receptor in the malignant phenotype of this tumor.

Animals↗
PubMed1989

Central nervous system infections in heart and heart-lung transplant recipients.

Infections, a major cause of morbidity and mortality in immunosuppressed heart and heart-lung transplant recipients, frequently involve the central nervous system and can produce devastating neurologic sequelae. Between 1980 and 1987, a total of 363 heart transplant and 54 heart-lung transplant recipients at the University of Pittsburgh sustained 13 intracranial infections two to 143 weeks after transplantation. Computed tomography demonstrated well-defined Nocardia and Aspergillus abscesses in four patients. Cerebrospinal fluid was normal in all cases studied, including in those patients in whom culture confirmed meningitis. Computed tomography-guided stereotactic surgery was used to diagnose and aspirate two nocardial brain abscesses. The prognosis for patients with central nervous system infections was related to their overall condition at the time of diagnosis. Both patients with nocardial abscesses and one patient with Listeria leptomeningitis survived, but all ten other patients died because of extensive multisystem infectious complications.

Adolescent↗
PubMed1989

Neuropathology of pediatric liver transplantation.

We reviewed the clinical histories and autopsy records of 35 pediatric patients (ranging in age from 9 months to 18 years) who underwent orthotopic liver transplantation using ciclosporin and corticosteroids for immunosuppression. At the time of death, 19 children (54%) had encephalopathy, 16 (46%) were lethargic or in coma, 10 (29%) had seizures, and 10 were normal. Neuropathological lesions were found on postmortem examination in all 35 patients. Vascular lesions such as infarction, ischemia, thrombosis, and hemorrhage were the most common neuropathological findings (86%) followed by infectious processes (29%). Candida albicans (2 patients) and Aspergillus fumigatus (3 patients) were the only offending organisms identified, both causing meningoencephalitis. Alzheimer type II astrocytes, a characteristic feature of chronic liver disease, were the single most common autopsy finding (69%). Central pontine myelinolysis was seen in 3 children and basilar artery thrombosis affected 1 child. Neurological complications and their subsequent neuropathology are a significant cause of morbidity and mortality after pediatric liver transplantation. Vascular insults, electrolyte abnormalities, and infections that involve the central nervous system are directly related to liver function and the immunosuppression necessary to maintain graft viability. Only with continued observation after surgery combined with rapid medical and surgical treatment can we hope to improve the prognosis following liver transplantation in the pediatric population.

Adolescent↗
PubMed1989

Recanalization of spinal arteriovenous malformations following embolization.

Recently, therapeutic embolization has been advocated as the treatment of choice for arteriovenous malformations (AVM's) of the spine. However, no study has established lasting benefit from this procedure or determined the incidence of recanalization, as occurs with cerebral AVM's. In this study, six patients were followed periodically after complete obliteration of their AVM's by particulate embolization was shown by immediate arteriography. The study group included three men (aged 59 to 72 years) with spinal dural arteriovenous (AV) fistulas and three women (aged 27 to 38 years) with intramedullary glomus-type spinal cord AVM's. The patients were treated by embolization with 100- to 1000-microns diameter polyvinyl alcohol particles. Clinical improvement, most commonly manifesting as increased lower-extremity strength, occurred in all patients after embolization. However, recurrent symptoms, including weakness, numbness, and urinary incontinence, occurred within 2 and 8 months in two of the three patients with dural AV fistulas and within 2 months in two of the three patients with glomus AVM's, prompting radiological reevaluation. Spinal arteriography revealed recanalization of the AV fistulas and spinal AVM's in five patients. Magnetic resonance (MR) imaging demonstrated a signal-void area caused by intramedullary AVM's. This area disappeared after embolic occlusion, but recurred after delayed recanalization, indicating restored flow through the AVM. Embolization provides only temporary treatment for many spinal AVM's. After embolic occlusion, delayed reassessment with arteriography and/or MR imaging is indicated, particularly if the symptoms persist or recur. Surgical excision of spinal AVM's provides the only therapeutic means to eliminate flow through the AVM permanently in most patients, and should be considered the treatment of choice when feasible.

Aged↗