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Biomedical subjects

R Bucholz

Publications and source records attributed to R Bucholz.

14 recordsLinked to original sources
PubMed2003

Local convection enhanced delivery of IL4-Pseudomonas exotoxin (NBI-3001) for treatment of patients with recurrent malignant glioma.

PURPOSE: This was an open-label, dose-escalation trial of intratumoral administration of IL-4 Pseudomonas Exotoxin (NBI-3001) in patients with recurrent malignant glioma. PATIENTS AND METHODS: A total of 31 patients with histologically verified supratentorial grade 3 and 4 astrocytoma were studied. Of these, twenty-five patients were diagnosed with glioblastoma multiforme (GBM) while six were diagnosed with anaplastic astrocytoma (AA). Patients were over 18 years of age and had Karnofsky performance scores > or = 60. Patients were assigned to one of four dose groups in a dose-escalation fashion: 6 microg/ml x 40 ml, 9 microg/ml x 40 ml, 15 microg/ml x 40 ml, or 9 microg/ml x 100 ml of NBI-3001 administered intratumorally via stereotactically placed catheters. Patients were followed with serial MRI scans and clinical assessments every four weeks for the first 16 weeks and then every eight weeks until week 26. RESULTS: No drug-related systemic toxicity, as evident by lack of hematological or serum chemical changes, was apparent in any patients; treatment-related adverse effects were limited to the central nervous system. No deaths were attributable to treatment. Drug-related Grade 3 or 4 toxicity was seen in 39% of patients in all dose groups and 22% of patients at the maximum tolerated dose of 6 microg/ml x 40 ml. The overall median survival was 8.2 months with a median survival of 5.8 months for the GBM patients. Six-month survival was 52% and 48%, respectively. Gadolinium-enhanced magnetic resonance imaging of the brain showed areas of decreased signal intensity within the tumor consistent with tumor necrosis following treatment in many patients. CONCLUSIONS: NBI-3001 appears to have an acceptable safety and toxicity profile when administered intratumorally in patients with recurrent malignant glioma.

Adult↗
PubMed2000

Automated rejection of contaminated surface measurements for improved surface registration in image guided neurosurgery.

Most image guided Neurosurgery employs adhesively mounted external fiducials for registration of medical images to the surgical workspace. Due to high logistical costs associated with these artificial landmarks, we strive to eliminate the need for these markers. At our institution, we developed a handheld laser stripe triangulation device to capture the surface contours of the patient's head while oriented for surgery. Anatomical surface registration algorithms rely on the assumption that the patient's anatomy bears the same geometry as the 3D model of the patient constructed from the imaging modality employed. During the time interval from which the patient is imaged and placed in the Mayfield head clamp in the operating room, the skin of the head bulges at the pinsite and the skull fixation equipment itself optically interferes with the image capture laser. We have developed software to reject points belonging to objects of known geometry while calculating the registration. During the course of development of the laser scanning unit, we have acquired surface contours of 13 patients and 2 cadavers. Initial analysis revealed that this automated rejection of points improved the registrations in all cases, but the accuracy of the fiducial method was not surpassed. Only points belonging to the offending instrument are removed. Skin bulges caused by the clamps and instruments remain in the data. We anticipate that careful removal of the points in these skin bulges will yield registrations that at least match the accuracy of the fiducial method.

Artifacts↗
PubMed1997

Treatment of acute fractures with a collagen-calcium phosphate graft material. A randomized clinical trial.

A prospective, randomized clinical trial was conducted concurrently at eighteen medical centers in order to compare the safety and efficacy of two types of graft material for the treatment of fractures of long bones: autogenous bone graft obtained from the iliac crest, and a composite material composed of purified bovine collagen, a biphasic calcium-phosphate ceramic, and autogenous marrow. Two hundred and thirteen patients (249 fractures) were followed for a minimum of twenty-four months to monitor healing and the occurrence of complications. We observed no significant differences between the two treatment groups with respect to rates of union (p = 0.94, power = 88 per cent) or functional measures (use of analgesics, pain with activities of daily living, and impairment in activities of daily living; p > 0.10). The prevalence of complications did not differ between the treatment groups except for the rate of infection, which was higher in the patients who were managed with an autogenous graft. Twelve patients who were managed with a synthetic graft had a positive antibody titer to bovine collagen; seven of them agreed to have intradermal challenge with bovine collagen. One patient had a positive skin response to the challenge but had no complications with regard to healing of the fracture. We concluded that, for traumatic defects of long bones that necessitate grafting, use of the composite graft material appears to be justified on the grounds of safety, efficacy, and elimination of the increased operative time and risk involved in obtaining an autogenous graft from the iliac crest.

Adult↗
PubMed1994

Intracranial neurosurgery guided by functional imaging.

Neurosurgery on eloquent cortex entails important risks of functional deficits complicating aggressive lesion resection. In this study, advanced biomagnetic functional imaging of somatosensory and motor cortex combined with surface rendered magnetic resonance imaging displays including vascular anatomy were used in conjunction with a new nonintrusive intraoperative guided instrumentation system to resect a tumor in eloquent cortex. Intraoperative verification of the accuracy of pre-operative motor localization demonstrated highly accurate results comparing direct stimulation and noninvasive presurgical mapping. The applicability of surface rendered combined functional and anatomic maps of cortex is directly evident on comparison of preoperative computer images and intraoperative pictures. This combination of new technologies has a significant potential for reduced risk and improved outcome in neurosurgery of eloquent cortex.

Brain Mapping↗
PubMed1989

Efficacy of barbiturates in the treatment of resistant intracranial hypertension in severely head-injured children.

Cerebral perfusion pressures (CPP) of less than 50 torr are associated with marginal cerebral blood flow and poor outcome. We report our experience with a group of 7 children who survived long period with CPP of less than 50 torr during treatment with pentobarbital. The study group was identified through a retrospective review of all head-injured patients admitted to Cardinal Glennon Memorial Hospital for Children between 1984 and 1986. All of the patients presented had sustained intracranial pressure of greater than 20 torr which was resistant to conventional therapy. All patients received pentobarbital for at least 24 h and all had documented CPP of less than 50 torr for more than 30 min during that time. Of these 7 children: 3 made good recoveries; 2 are moderately disabled, and 2 are vegetative. Neither the CPP nor the length of pentobarbital coma was an accurate predictor of outcome. It seems likely that these children are a subset of those previously defined as having resistant intracranial hypertension and that, as a group, they may have benefited from pentobarbital administration. It is also apparent that, in this group, low CPP was not indicative of irreversible brain damage or brain death.

Adolescent↗
PubMed1984

A coralline hydroxyapatite bone graft substitute. Preliminary report.

Experimental histologic and biomechanical studies were performed in 52 dogs by use of a bone substitute composed of hydroxyapatite converted from sea coral calcite. The results demonstrate some potentially useful practical applications. The material was totally incorporated in bone. Although initially too weak to tolerate physiologic stresses, once incorporated it becomes almost as strong as the native bone. Clinical experience with internal fixation of fractures with hydroxyapatite in 18 patients is encouraging.

Adult↗
PubMed1981

Evoked somatosensory potentials to common peroneal nerve stimulation in man.

This study was undertaken to identify the normal somatosensory evoked potential pattern from stimulation of the common peroneal nerve in order to provide basic data for clinical use in diagnosis and management of patients with spinal cord lesions. Thirty-four adult volunteers, free of neurological disease, and 12 patients were tested. The recording technique is described and is similar to that reported by Perot. The primary evoked response (P1) was easily visualized in 88% of the recordings from normal subjects. The peak latency of the primary response was 38.9 msec, and the deflection was positive. A vertex potential (P4) was a relatively consistent peak that appeared at approximately 240 msec in 78% of the subjects. Additional components of the waveform are also described and are compared to previous studies. Clinically, the presence of primary response seems to correlate with a favorable neurological outcome, and recovery of the primary response may precede major clinical improvement. The literature is reviewed and results compared to the current study.

Adolescent↗
PubMedDate not supplied

New strategy for the cultivation of microalgae using microencapsulation.

The four species of microalgae (Dunaliella bardawil, Chlorella minutissima, Pavlova lutheri and Haematococcus pluvialis) were immobilized in Ca-alginate capsules as a basic study for the development of the economic cultivation process. Under the batch culture of aerobic conditions, the thickness of the capsule membrane and CO2 supply did not affect the growth of the immobilized microalgae, Dunaliella bardawil. Cell concentration of immobilized microalgae in the capsule was higher than those of immobilized microalgae in beads and free cells. The cell concentrations of microencapsulated Dunaliella bardawil and Haematococcus pluvialis were five times greater than that of free cells. Based on these results, microencapsulation for the culture of microalgae was an effective method for the high-density cultivation. In comparison to the immobilized cultivation on the bioreactor type, it was more effective for the cultivation in the bubble column bioreactor than that in the stirrer tank bioreactor.

Bioreactors↗
PubMedDate not supplied

Sarcoid tumor in skeletal muscle. A case report.

The 3 patterns of sarcoid involvement of skeletal muscle are microscopic infiltration, progressive myopathy and tumor formation. This is a case report and review of investigations of a 25-year-old man with the unusual tumorous form.

Adult↗