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Biomedical subjects

J W Martin

Publications and source records attributed to J W Martin.

At least 55 records · Page 3Linked to original sources
PubMed1995

Morphometric abnormalities in brains of great blue heron hatchlings exposed in the wild to PCDDs.

Great blue heron hatchlings from colonies in the Strait of Georgia, British Columbia, Canada are being monitored for environmental contaminant exposure and effects by the Canadian Wildlife Service. The contaminants of concern are polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), primarily derived from kraft pulp mill effluent. The levels of PCDDs and PCDFs in eggs from the most contaminated colonies peaked in 1988 and 1989 and dropped dramatically through 1990 to 1992. Brains of heron hatchlings (taken as eggs from the wild and hatched in the laboratory) were analyzed for gross morphological abnormalities. Brains from highly contaminated colonies (Crofton, British Columbia and University of British Columbia Endowment Lands) in 1988 exhibited a high frequency of intercerebral asymmetry. The frequency of this abnormality decreased in subsequent years as the levels of TCDD and TCDD-TEQs (toxic equivalence factors) decreased. The asymmetry was significantly correlated with the level of TCDD and TCDD-TEQs in eggs taken from the same nest. Yolk-free body weight negatively correlated and the brain somatic index positively correlated with the TCDD level in such pair-matched eggs. These results indicate that gross brain morphology, and specifically intercerebral asymmetry, may be useful as a biomarker for the developmental neurotoxic effects of PCDDs and related chemicals.

Abnormalities, Drug-Induced↗
PubMed1995

Minimizing oral complications of cancer treatment.

Aggressive cancer therapy places patients at greater risk for oral complications and treatment-related consequences. Unfortunately, prevention and/or treatment of such oral sequelae have become often overlooked priorities of the treatment team. We describe a philosophy of management of the cancer patient that specifically emphasizes the prevention and treatment of oral complications associated with cancer therapy. These concepts and principles are based on treatment protocols and ongoing clinical practices at The University of Texas M. D. Anderson Cancer Center in Houston, Texas.

Antineoplastic Agents↗
PubMed1994

Micronuclei, a biomarker for chemoprevention trials: results of a randomized study in oral pre-malignancy.

Biomarkers are being sought that could serve as surrogate end points for chemoprevention trials. Micronuclei, cytoplasmic fragments of DNA, have been proposed as a biomarker and studied in oral pre-malignancy. This study evaluated micronuclei frequency in a randomized chemoprevention trial of oral pre-malignancy. A recent clinical trial evaluated the responses of pre-malignant oral lesions to 3 months of therapy with isotretinoin followed by 9 months of either low-dose isotretinoin or beta-carotene. For 57 study participants, micronuclei were counted in mucosal scrapings of the lesion and in normal-appearing mucosa at baseline and following 3 months and 12 months of therapy. Micronuclei counts were higher in scrapings from the lesion than in the normal-appearing mucosa. Following 3 months of isotretinoin, the micronuclei counts in scrapings of the lesion were significantly reduced. With treatment, the mean micronuclei count declined at 3 months. In a randomized comparison, both isotretinoin and beta-carotene maintained the suppression of micronuclei. The change in micronuclei count was not associated with the clinical or histological response to treatment. Chemoprevention treatment with isotretinoin led to a reduction in frequency of micronuclei, a marker of recent DNA injury, which was then maintained by both isotretinoin and beta-carotene.

Biomarkers, Tumor↗
PubMed1994

Blood transfusion and blood conservation: cost and utilization issues.

Approximately 12 million red blood cell units are transfused to nearly 4 million patients annually in the United States (1). The conservation of blood has historically arisen from awareness that the inventory of this resource is limited (2), as well as the knowledge that blood transfusion carries a risk (3). Estimates of current blood transfusion risks (4-12), and the costs of transfusion complications (13-17), are summarized in Table 1. In addition, emphasis on the costs of health care has raised issues related to the costs of blood transfusion (18, 19). Finally, recent guidelines have emphasized that in the elective transfusion setting, no blood transfusion is a desirable outcome (20, 21). Furthermore, these guidelines along with consensus conference recommendations (22) have emphasized that if blood is to be transfused, autologous (the patient's own) blood is preferable to allogeneic (from an anonymous, volunteer donor) blood. Thus, the costs of blood conservation, for which an increasing array of technologic procedures and products have become available (Table 2), have also become an issue (23). The purpose of this review is to provide an overview of emerging data on the cost-effectiveness of blood and blood conservation interventions in order to help identify areas important for future investigation.

Blood Loss, Surgical↗
PubMed1994

Seminar planning guidelines. As I see it.

Small local chapter groups can present quality cost effective regional seminars. Key components are dedication of members, teamwork, and a sense of direction. The following guidelines and information can provide a framework for planning and coordinating a seminar.

Education, Nursing, Continuing↗
PubMed1994

Maxillofacial restoration after tumor ablation.

Communication between the surgeon and the maxillofacial prosthodontist before, during, and after surgery is the most important aspect to successful prosthetic rehabilitation of the head and neck cancer patient. Surgeons should understand the problems and limitations involved in prosthetic rehabilitation so that the patient is adequately educated during rehabilitation. Osseointegrated implants, although an important advancement in this field, should not take the place of proper defect preparation. The use of implants in the irradiated patient is currently being evaluated by controlled studies. However, if implants are used, then their position and number should be carefully planned in the pretreatment phase. Preparation of the defect by skin grafting and controlling the position of the remaining structures is important to the overall aesthetic and functional result of the prosthesis.

Head and Neck Neoplasms↗
PubMed1994

Postoperative care of the maxillectomy patient.

Guidelines for preoperative patient information and immediate postoperative care of the maxillectomy patient are discussed. Physical therapy, oral hygiene procedures, and current materials for surgical obturation and their uses are reviewed. Effective treatments for infections that arise in the surgical defect are highlighted.

Humans↗
PubMed1993

Comparison of low-dose isotretinoin with beta carotene to prevent oral carcinogenesis.

BACKGROUND: High-dose isotretinoin therapy has been determined to be an effective treatment for leukoplakia. However, a high rate of relapses and toxic reactions led us to conduct a trial of a much lower dose of isotretinoin in the hope of maintaining a response and limiting toxicity. METHODS: In the first phase of the study, 70 patients with leukoplakia underwent induction therapy with a high dose of isotretinoin (1.5 mg per kilogram of body weight per day) for three months; in the second phase, patients with responses or stable lesions were randomly assigned to maintenance therapy with either beta carotene (30 mg per day) or a low dose of isotretinoin (0.5 mg per kilogram per day) for nine months. RESULTS: In the first phase, the rate of response to high-dose induction therapy in the 66 patients who could be evaluated was 55 percent (36 patients). The lesions of seven patients progressed, and therefore they did not participate in the second phase of the trial. Of the 59 patients included in the second phase, 33 were assigned to beta carotene therapy and 26 to low-dose isotretinoin therapy; these two groups did not differ significantly in prognostic factors. Of the 53 patients who could be evaluated, 22 in the low-dose isotretinoin group and 13 in the beta carotene group responded to maintenance therapy or continued to have stable lesions (92 percent vs. 45 percent, P < 0.001). In situ carcinoma developed in one patient in each group, and invasive squamous-cell carcinoma in five patients in the beta carotene group. Toxicity was generally mild, though greater in the group given low-dose isotretinoin therapy. CONCLUSIONS: When preceded by high-dose induction therapy, low-dose isotretinoin therapy was significantly more active against leukoplakia than beta carotene and was easily tolerated.

Adult↗
PubMed1993

Technique for controlling the thickness of a facial prosthesis when an acrylic resin core is used.

A technique for evaluating the acrylic resin core before processing a silicone facial prosthesis is described. The technique involves the use of either irreversible hydrocolloid impression material or silicone to identify thin areas in the pattern. This simple yet effective procedure ensures adequate thickness and strength of the silicone prosthesis, which in turn decreases the amount of chair and laboratory time needed at the delivery appointment.

Acrylic Resins↗
PubMed1993

Reinfusion of whole blood after revision surgery for infected total hip and knee arthroplasties.

Because of its proven effectiveness in reducing the need for banked blood transfusions following total joint arthroplasty, the indications for postoperative blood retrieval were expanded to include seven cases of infected total knee or hip arthroplasties where a one-stage exchange procedure was performed. Each joint had been aspirated after surgery and had positive cultures but no gross pus at the time of revision surgery. Each of the operations included debridement with reimplantation of a cementless prosthesis under cover of intravenous antibiotics for 48 hours followed by oral treatment until discharge. Antibiotic-soaked morselized bone graft was used in all patients to restore deficient nonstructural bone. Wound drainage blood was retrieved and reinfused during the first 8 hours after surgery, averaging 958 cc. Banked blood usage averaged 2.4 U (88% homologous) with an average blood loss of 1,974 cc. One patient experienced shaking chills during a second reinfusion of 600 cc of blood without stoppage of the transfusion. Wound hematoma occurred in one patient but did not require surgical evacuation. No patient developed evidence of septicemia.

Blood Transfusion↗
PubMed1993

Reinfusion of whole blood following addition of tobramycin powder to the wound during total knee arthroplasty.

This study prospectively examined nine human volunteers who underwent unilateral cementless total knee arthroplasty and had 600 mg of tobramycin powder added to their wound just prior to fascial closure. Serum levels of tobramycin were measured at 30 minutes, 4 hours, 8 hours, and 12 hours after surgery. Tobramycin levels in the reinfused whole blood were measured with each reinfusion. Patients were reinfused up to 12 hours after surgery and then the reservoir was left to suction drainage. All patients had significant levels of serum tobramycin 30 minutes after surgery. The average serum level was 5.5 micrograms/ml (range, 3.0-10.6 micrograms/ml). This level was achieved prior to any reinfusion and represented systemic absorption of tobramycin from the bleeding surfaces of the muscle and bone. All patients received at least one reinfusion of 400 ml of whole blood in the first 8 hours after surgery. Two thirds of the patients received a second reinfusion within the same time frame. Serum tobramycin levels measured post-reinfusion indicated that the risk of attaining potential toxic levels of aminoglycoside was not dependent on reinfusion, but on absorption from the wound. The dose of tobramycin in the drain was measured and found to be excessive and potentially toxic (range, 27-312 mg; average, 132 mg). Despite this fact, reinfusion was not as likely to produce toxic serum levels as was local uptake of the antibiotic. Although no patient in this series had any complaints relating to the high dose of tobramycin (deafness or renal failure), caution should be exercised when using antibiotics in a reinfusion system.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed1993

Mandible fragment fixation during reconstruction: the splint-and-plate technique.

One of the most popular methods of mandible fragment fixation is the precontoured reconstruction plate technique. Unfortunately, this method is not a reliable option when tumor distorts the mandibular contour or extends through the buccal cortex of the mandible. An alternative to the precontoured reconstruction plate is the splint-and-plate technique of mandible fragment fixation. An application of this appliance and method in 10 patients revealed the technique's advantages. The splint can be applied quickly and does not obstruct the ablative or reconstructive procedure. Further, the splint accurately keys the dentition and reliably maintains temporomandibular joint relationships. Finally, this technique provides a reference point to the exact position of the symphysis and angle when these landmarks have been resected.

Adult↗
PubMed1993

Chemoprevention as a form of cancer control.

Once considered a futuristic concept, chemoprevention for pre-malignant oral leukoplakia lesions is now a reality. Oral leukoplakia can proceed to invasive disease and expose the upper aerodigestive tract to carcinoma. Risk factors, diagnosis and research in chemoprevention are discussed.

Erythroplasia↗
PubMed1992

An acrylic resin core for processing silicone facial prostheses.

A technique is presented for making an acrylic resin core for processing silicone facial prostheses. This technique ensures a durable core that can be used to make multiple prostheses. The core resists fungal growth during storage and creates a smooth, easily cleanable internal surface for a facial prosthesis. The core also permits a controllable thickness and therefore a lighter prosthesis.

Acrylic Resins↗
PubMed1992

A flasking technique for microwave processing of silicone prostheses.

Polyvinylchloride plumbing parts provide a readily available source of material to use in making facial prostheses. Inexpensive pipe fittings (end cap attachments and closet flanges) can be combined to provide a durable container for stone molds that can be tightened in a strong curing press. The entire unit can be cured in a microwave oven in 30 minutes.

Dental Prosthesis Design↗