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Biomedical subjects

G Goodman

Publications and source records attributed to G Goodman.

At least 73 records · Page 4Linked to original sources
PubMed1991

Predicting the carcinogenicity of chemicals in humans from rodent bioassay data.

Regulatory agencies currently rely on rodent carcinogenicity bioassay data to predict whether or not a given chemical poses a carcinogenic threat to humans. We argue that it is always more useful to know a chemical's carcinogenic potency (with confidence limits) than to be able to say only qualitatively that it has been found to be a carcinogen. In a typical bioassay, a chemical is administered to groups of 50 to 100 rodents at the highest feasible level (the maximum tolerated dose) and rarely at less than 1/10 this dose in order to maximize the statistical significance of any increase in tumors that might result. Recently, much experimental work has focused on the mechanisms by which site-specific toxicity arising from chronic administration at the maximum tolerated dose may lead to carcinogenicity. Extrapolation of high-dose results to low doses does not take into consideration the possibility of a threshold dose, below which the carcinogenic potency is much lower or even zero. Threshold dose-response phenomena may be much more relevant to the etiology of cancer in the rodent bioassays than was earlier realized; if so, there is an even greater need for establishing dose-dependent potency estimates. The emphasis of this review is on the interspecies comparison of high-dose potencies. The qualitative and quantitative comparison of carcinogenicities between mice and rats and between rodents and humans is reviewed and discussed. We conclude that there is a good qualitative (yes/no) correlation for both the rat/mouse and the rodent/human comparison. There is also a good correlation of the carcinogenic potencies between rats and mice, and the upper limits on potencies in humans are consistent with rodent potencies for those chemicals for which human exposure data are available. For the rodent/human comparison, the best estimate of the interspecies potency factor is lognormally distributed around 1 when the potencies in both species are measured in units of (mg/kg-day)-1.

Animals↗
PubMed1991

The effects of a short thumb opponens splint on hand function in cerebral palsy: a single-subject study.

An AB single-subject research design was used to assess the effectiveness of a short thumb opponens splint on hand function in a 4-year-old girl with cerebral palsy. Baseline data for active range of motion, grip and pinch strength, grasp patterns, the Box and Block Test of manual dexterity (Mathiowetz, Voland, Kashman, & Weber, 1985), and 1-in. cube stacking were collected twice a week for 4 weeks. The child was fitted with a short thumb opponens splint, which was worn 6 hr during the day and all night for 4 weeks. The twice-weekly measures of the dependent variables continued during the treatment phase. Visual and statistical analysis of the data indicate that the child showed a clinically significant improvement in palmar and radial abduction, thumb opposition, grip strength, performance on the Box and Block Test scores, cube stacking, and lateral pinch. These results suggest that for this child with cerebral palsy, the use of a short thumb opponens splint improved underlying aspects of hand function as well as hand function itself. Replication of this study with a more complex single-subject design involving more subjects is recommended to confirm these results.

Biomechanical Phenomena↗
PubMed1990

High-dose cisplatin in disseminated melanoma: a comparison of two schedules.

A total of 38 patients with metastatic melanoma received monthly chemotherapy with cisplatin at a dose of 200 mg/m2, per cycle; 14 received 20 mg/m2 cisplatin i.v. on days 1-5 and 24 were given 100 mg/m2 i.v. on days 1 and 8. Objective responses were seen in 2/14 treated on days 1-5 and in 5 of 22 evaluable subjects receiving cisplatin on days 1 and 8, for an overall response rate of 22%. The median survival of all patients was 6 months, with no significant difference observed between the two schedules. Severe neurotoxicity and myelosuppression were more common in patients treated on days 1-5. Two patients treated in this manner were bedridden due to neurotoxicity and four developed grade 4 leukopenia after the first cycle of chemotherapy. Only one patient treated with the divided-dose schedule became leukopenic during the first cycle, and none of the patients were debilitated by neurotoxicity. Thrombocytopenia was statistically more severe. Nausea and vomiting, fatigue, ototoxicity, and paresthesia were seen with equal frequency. Very high doses of cisplatin can be delivered with acceptable toxicity using a divided-dose schedule. As the response rate on this schedule appeared to be comparable with that achieved on the more toxic consecutive 5-day schedule, the former deserves to be tested in diseases known to show a dose response to cisplatin. However, in melanoma, administration of 200 mg/m2 per course did not appear to be associated with a markedly improved response rate, compared with cisplatin alone at "standard" doses.

Adult↗
PubMed1990

The degree of roentgenographic parenchymal opacities attributable to smoking among asbestos-exposed subjects.

Considerable controversy surrounds the question of whether cigarette smoking has the potential to increase the prevalence of small opacities on chest roentgenographs among asbestos-exposed workers. To compare the relative contribution of smoking with other predictors of the presence of roentgenographic small opacities, we examined 661 men enrolled in a double-blind, randomized trial designed to assess the efficacy of vitamin A and beta-carotene in the prevention of lung cancer among workers with heavy occupational asbestos exposure. Subjects in the study population had a mean latency of 35 yr from first asbestos exposure and a mean of 28 yr in their trade. The prevalence of roentgenographic abnormalities consistent with asbestos exposure was 26% for pleural abnormalities alone, 10% for parenchymal abnormalities alone, and 20% for pleural and parenchymal abnormalities together. We investigated occupation, age, latency from first asbestos exposure, and smoking status as predictors of roentgenographic small opacities. Smoking history, independent of latency, contributed to the prevalence and extent of small opacities, but its effect was less than that of latency. We conclude, that in the setting of heavy occupational exposure to asbestos, cigarette smoking confers added risk for the development of roentgenographic small opacities.

Aged↗
PubMed1990

Visual disabilities related to intraocular lens design.

Intraocular lens implantation after cataract extraction has become a common practice in the United States. However, unwanted optical images can correct an otherwise successful surgery into one that causes patient dissatisfaction. Refinements in manufacturing design and finishing have greatly improved the quality of present day intraocular lenses, but there is continued interest in simulating the optics of the human crystalline lens. We will discuss the optical requirements of intraocular lenses and how these are influenced by optic design and dimension, and spectral transmission characteristics.

Humans↗
PubMed1989

Psychology and self-help groups. Predictions on a partnership.

Continued growth and increased legitimacy are anticipated for the American self-help group (SHG) phenomenon. Currently estimated at six and a quarter million participants annually, self-help groups will assume a central role in the nation's mental health delivery system over the next two decades. The first part of this article illuminates the self-help group phenomenon itself. Its scope, characteristics, supporting social climate, and associated research issues are reviewed. The second part is a futuristic examination of its interface with the newly industrializing world of health care. Massive increases in mental health services are predicted, especially via the SHG format. Theory development, research sophistication, changing SHG formats, a place in public policy, and acceptance into graduate curricula are also expected, as are collaborative relationships with a variety of professional disciplines. Psychologists are urged to enhance the relevance of the profession by taking an early leadership role in these developments.

Community Mental Health Services↗
PubMed1989

Posterior chamber intraocular lens implantation in the absence of posterior capsular support.

Because of the high incidence and great variety of complications associated with anterior chamber intraocular lenses, we have developed a technique for the implantation of a posterior chamber intraocular lens in the absence of posterior capsular support. The posterior chamber IOL is placed in the ciliary sulcus by suturing the superior haptic to the iris and the inferior haptic to the sclera at the ciliary sulcus. We have used this technique successfully in both complicated extracapsular surgery and secondary intraocular lens implantation.

Follow-Up Studies↗
PubMed1989

The systems approach: an innovative model for improving the delivery of inservice training.

A systems approach consisting of eight elements was used in the design, implementation, and evaluation of a module for physical therapy inservice training at McDonald Army Hospital, Fort Eustis, Virginia. Use of this approach was aimed at increasing the effectiveness of learning, improving participant attitudes toward inservice training, and developing a model which could be used for delivering inservice training throughout the helping professions. The design requires that the problem area be selected by staff consensus--in this case planning and administration of therapeutic exercise programs for patients with hip dysfunctions. Five sessions which centered around this patient oriented problem area were presented by the physical therapist to the three physical therapy technicians. Principles of instructional design and events of instruction were incorporated using the format of Gagne and Briggs (1979). The technicians' perception of physical therapy inservice training was rated before the implementation of the systems approach, after the second inservice session, and after the final inservice session. By the end of the five inservice sessions, all three technicians were able to accomplish the predetermined goal of planning and administering a safe therapeutic exercise program to patients with hip dysfunctions. Progress notes also indicated that patient programs were being appropriately upgraded based on the patient's condition. Technicians' ratings of inservice training also had increased after the final session. Further implementation and evaluation of this approach to training is recommended.

Attitude↗
PubMed1988

Pulmonary hypertension in infants with bronchopulmonary dysplasia.

Seventeen children with oxygen-dependent bronchopulmonary dysplasia, right ventricular hypertrophy, and Doppler echocardiographic evidence of pulmonary hypertension were studied by cardiac catheterization. Fifteen of these patients had pulmonary hypertension when placed in room air; six of these 15 patients were shown to have large systemic-to-pulmonary collateral vessels. The hemodynamic responses to oxygen and hydralazine were evaluated. Five patients developed normal pulmonary artery pressure while receiving supplemental oxygen and were not studied further. Of the remaining ten patients, the six patients with large, hemodynamically significant collateral vessels all had deleterious reactions to hydralazine. Two of the four patients without collateral pulmonary circulation responded to hydralazine with further reductions in mean pulmonary artery pressure. Five of the ten patients who had persistent pulmonary hypertension while receiving oxygen have died. Cardiac catheterization and angiography may provide important diagnostic, therapeutic, and prognostic information in patients with pulmonary hypertension complicating bronchopulmonary dysplasia.

Bronchopulmonary Dysplasia↗
PubMed1988

Postoperative complication in a patient with a silicone intraocular lens.

A 58-year-old white male patient developed corneal complications following cataract surgery and implantation of a silicone posterior chamber intraocular lens. At the time of penetrating keratoplasty, the implant was noted to be partially dislocated into the anterior chamber, surrounded by a dense fibrovascular membrane. Histopathological features were consistent with pseudophakic bullous keratopathy.

Cornea↗
PubMed1988

Posterior chamber intraocular lens implantation in the absence of posterior capsular support.

Because of the high incidence and great variety of complications associated with anterior chamber intraocular lenses, we have developed a technique for the implantation of a posterior chamber intraocular lens in the absence of posterior capsular support. The posterior chamber IOL is placed in the ciliary sulcus by suturing the superior haptic to the iris and the inferior haptic to the sclera at the ciliary sulcus. We have used this technique successfully in both complicated extracapsular surgery and secondary intraocular lens implantation.

Cataract Extraction↗
PubMed1987

The distance between cytochromes a and a3 in the azide compound of bovine-heart cytochrome oxidase.

The electron-spin relaxation rates of the two species of cytochrome a3(3+)-azide found in the azide compound of bovine-heart cytochrome oxidase were measured by progressive microwave saturation at T = 10 K. It has been shown previously that Cyt a3(3+)-azide gives rise to two distinct EPR resonances, depending upon the oxidation state of Cyt a. When Cyt a is ferrous, Cyt a3(3+)-azide has g = 2.88, 2.19 and 1.64; upon oxidation of Cyt a, the a3(3+)-azide g-values become g = 2.77, 2.18, and 1.74 (Goodman, G. (1984) J Biol. Chem. 259, 15094-15099). The relaxation effect of Cyt a on Cyt a3 could be measured as the difference in microwave field saturation parameter H1/2 between the g = 2.77 and g = 2.88 species. For each signal the spin-lattice relaxation time T1 was determined from H1/2 using the transverse relaxation time T2. The value of T2 at 10 K was extrapolated from a plot of line-width vs. temperature at higher temperature. The dipolar contribution to T1 was related to the Cyt a-Cyt a3 spin-spin distance utilizing available information on the relative orientation of Cyt a3-azide and Cyt a (Erecińska, M., Wilson, D.F. and Blasie, J.K. (1979) Biochim. Biophys. Acta 545, 352-364). By taking into account the relaxation parameters for both gx and gz components of the Cyt a3-azide g-tensor, the angle between the gz components of the Cyt a and Cyt a3 g-tensors was determined to be between 0 and 18 degrees, and the Cyt a-Cyt a3 spin-spin distance was found to be 19 +/- 8 A.

Anaerobiosis↗
PubMed1987

Intraaortic balloon pump insertion: a randomized study comparing percutaneous and surgical techniques.

To compare the percutaneous and surgical techniques of intraaortic balloon pump insertion, 101 patients referred for this procedure were randomly assigned to either percutaneous or surgical insertion. Insertion using the designated technique was successful in 45 (88%) of 51 patients with percutaneous insertion and 48 (96%) of 50 patients with surgical insertion (difference not statistically significant). The time from the beginning of the insertion procedure to the initiation of counterpulsation was 13 +/- 8 minutes for the percutaneous technique versus 31 +/- 16 minutes for the surgical technique (p less than 0.001). In the percutaneous group, 10 patients required Fogarty thrombectomy after balloon pump removal, and 1 patient developed severe leg ischemia requiring immediate termination of balloon pump support. In the surgical group, one patient developed leg ischemia requiring surgical intervention, three patients developed sepsis with bacteremia (including one patient who required vein patch repair of the femoral artery), one patient developed a wound infection requiring debridement and one patient had a cerebral embolus. Aortic dissection, aortoiliac perforation or amputation did not occur in either group. Major vascular complications occurred in 11 patients (22%) with percutaneous insertion versus 2 patients (4%) with surgical insertion (p less than 0.05). It is concluded that although the percutaneous technique for intraaortic balloon pump insertion is faster than the surgical technique and is technically easy, it is associated with a higher incidence of vascular complications.

Blood Pressure↗