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Biomedical subjects

A R Baker

Publications and source records attributed to A R Baker.

69 records · Page 4Linked to original sources
PubMed1985

Localization of an occult insulinoma by intraoperative ultrasonography.

Intraoperative ultrasonography has not been used previously to locate an insulinoma that was not surgically palpable or that could not be seen by selective arteriography. In this report we described a patient with an insulinoma localized to the pancreatic head identified by transhepatic portal venous sampling but not by selective arteriography or palpation. At operation intraoperative ultrasonography demonstrated an 8 mm tumor in the pancreatic head and guided the successful enucleation.

Adenoma, Islet Cell↗
PubMed1985

The Tikhoff-Linberg procedure: report of ten patients and presentation of a modified technique for tumors of the proximal humerus.

The Tikhoff-Linberg resection is a limb-sparing surgical option to be considered for bony and soft-tissue tumors in and around the proximal humerus and shoulder girdle. Careful selection of patients whose tumor does not involve the neurovascular bundle in the axilla is required. The distal clavicle, upper humerus, and part or all of the scapula are resected. The tumor remains covered by the deltoid muscle plus portions of the muscles that arise from or insert into the resected specimen. In patients with tumors of the proximal humerus a custom prosthesis is used to maintain length and stabilize the distal humerus. Elbow flexion plus stability of the shoulder without the need of an orthosis may be achieved with muscle transfers. Function of the hand and forearm after Tikhoff-Linberg resection should be near normal. Review of results in 10 patients shows no local recurrences and excellent function. The major postoperative problem was nerve palsy. The Tikhoff-Linberg procedure should continue to be used for limb salvage in selected patients with tumors in or around the shoulder girdle.

Adolescent↗
PubMed1984

Radical forequarter amputation with chest wall resection.

Forequarter amputation with resection of the chest wall is indicated for primary bony and soft tissue tumors involving the shoulder girdle, axilla, and chest wall, as well as for recurrent breast cancer in the axilla after irradiation. We describe a modification of this procedure that includes an initial thoracotomy for intraoperative staging and a median sternotomy, which avoids individual division of the anterior ribs and clavicle.

Adult↗
PubMed1983

Epitrochlear node involvement in melanoma of the upper extremity.

Between 1955 and 1979, 240 patients with melanoma of the upper extremity were admitted to the National Institutes of Health (NIH). Thirty nine of these patients (16%) had primary lesions of the forearm, hand, or digit. Twenty-two patients underwent axillary dissection during their treatment. Ten patients were subjected to both axillary and epitrochlear lymph node dissection. Nine of these ten patients had lymph node metastases; two in the axillary nodes only, two in the epitrochlear nodes only, and five in both nodal groups. Epitrochlear node involvement occurred in 18% of patients with forearm or hand lesions, and only when the primary melanoma was within 5 cm of the elbow or in the ulnar distribution, the classically described drainage area of the epitrochlear nodes. The prognosis of the patients in this study was related to the depth of their primary lesions and the presence or absence of axillary node involvement. However, since approximately 18% of patients with melanomas of the hand, forearm and elbow area have a high probability of recurrence in the epitrochlear nodes, close attention to this area and early dissection of clinically suspicious nodes can favorably affect locoregional control in this group of melanoma patients.

Adult↗
PubMed1978

Failure of immunotherapy with neuraminidase-treated tumor cell vaccine in mice bearing established 3-methylcholanthrene-induced sarcomas.

C3H/HeJ mice bearing MC-80 fibrosarcomas were given immunotherapy consisting of multiple injections of a Vibrio cholerae neuraminidase (VCN)-treated tumor cell vaccine at a site remote from the established tumor. In five separate experiments we were unable to show either partial or complete tumor regression or prolongation of survival for vaccine-treated mice compared to appropriate controls. Further, the use of BCG in addition to VCN-treated tumor cells failed to show any therapeutic efficacy. We could not confirm the successful immunotherapy results reported by others despite multiple efforts of reproduce the immunotherapy model as carefully and precisely as possible.

Animals↗
PubMed1976

Chronic pain control by means of an epidural catheter: report of a case with description of the method.

The feasibility of long-term epidural catheterization for control of chronic pain from sacral metastases has been demonstrated. Infection was not a problem and obstruction of the catheter did not occur. The short duration of action of currently available drugs was the major limitation of the technique. The technique described merits further investigation as an alternative to currently available methods.

Anesthetics, Local↗
PubMedDate not supplied

Tracer technique to measure in vivo chemical transport rates within an implantable cell transplantation device.

An in vivo tracer technique that uses radiolabeled insulin as the tracer molecule has been developed to assess the rate of chemical transport between the cell transplantation chamber of an implantable bioartificial device and the host's circulatory system. The device considered here employs site-directed neovascularization of a porous matrix to induce capillary growth adjacent to an immunoisolated cell implantation chamber. This device design is being investigated as a vehicle for therapeutic cell transplantation, with the advantages that it allows the cells to perform their therapeutic function without the danger of immune rejection and it avoids damaging contact of blood flow with artificial surfaces. A pharmacokinetic model of the mass transport between the implantation chamber, the vascularized matrix, and the body has been devised to allow proper analysis and understanding of the experimental tracer results. Experiments performed in this study have been principally directed at evaluation of the tracer model parameters, but results also provide a quantitative measure of the progression of capillary growth into a porous matrix. Measured plasma tracer levels demonstrate that chemical transport rates within the implanted device increase with the progression of matrix vascular ingrowth. Agreement between the fitted model curves and the corresponding measured concentrations at different levels of capillary ingrowth demonstrate that the model provides a realistic representation of the actual capillary-mediated transport phenomena occurring within the device.

Animals↗
PubMedDate not supplied

Evaluation of an immunoisolation membrane formed by incorporating a polyvinyl alcohol hydrogel within a microporous filter support.

An immunoisolation membrane formed by incorporating a high water content polyvinyl alcohol (PVA) hydrogel into a microporous polyether sulfone (PES) filter has been investigated in this study. The PVA hydrogel is formed in situ within the filter pores via glutaraldehyde (GA) crosslinking under acidic conditions. The tortuous nature of the microporous filter pores securely anchors the embedded hydrogel to provide excellent structural integrity. The high void fraction of the PES filter support (>80%) and high water content of the PVA hydrogel (>85% water by weight) allow excellent solute transport rates, while an appropriate level of glutaraldehyde crosslinking supplies the required molecular size selectivity. In vitro permeability measurements made with solutes covering a wide range of molecular sizes demonstrate high transport rates for small nutrient molecules with rapidly diminishing permeabilities above a molecular weight of approximately 1,000 Dalton. Implantation experiments show that the membrane properties are not deleteriously affected by prolonged in vivo exposure or common sterilization techniques. Thus, this hybrid hydrogel/filter membrane system offers a promising approach to the immunoisolation of implanted cells.

Animals↗