Biomedical subjects
Publications and source records attributed to B Steinberg.
There are several techniques available to the practitioner for the treatment of impacted, fully developed teeth. These techniques often involve surgical and/or orthodontic manipulation of the affected tooth. A more conservative approach was used in the case presented here, involving a boy who was 12 years 5 months old. An odontoma was surgically removed and the impacted tooth was allowed to erupt without the aid of external forces.
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Twenty-four LSH and LVG strain golden hamsters, Mesocricetus auratus, were used. Experimental animals were maintained at 5 C and allowed to hibernate. Control animals were kept at 27 C. Six animals (3 experimental, 3 control) were injected subcutaneously with 1 microCi of 3H-proline/gm body wt. (Spec. act. 3 Ci/mM) after hibernation lasting 12 hours, 1 day, 3 days, or 7 days. Animals were killed 1 hour after injection and autoradiographs were prepared from 5 microns thick decalcified sections of femurs. A greater number of endosteal cells were labeled than periosteal cells and also exhibited a greater magnitude of labeling throughout the study. Differences between endosteal and periosteal cells both in percentage of cells labeled and magnitude of labeling were maximum in control animals and progressively decreased with increasing periods of hibernation. A reduction in synthesis of matrix proteins during the early period of hibernation was seen and was attributed to a significant reduction both in average cell activity and in the number of active cells during hibernation. The latter phenomenon apparently made a large contribution to the reduced matrical synthesis. 3H-proline uptake by osteoblasts probably reflects the reduced requirements of matrical synthesis during hibernation.
Surgery for cancer in man is followed by immunosuppression, and immunosuppressed cancer patients have advanced stage and poor prognosis. Yet surgery continues to offer the best chance for cure for patients with solid tumors. Since natural-killer cells appear to play a major role in control of tumor metastases in experimental animals, we studied peripheral blood T-cell subsets and natural-killer cytotoxicity of 75 patients with colorectal cancer preoperatively and between 1 and 3 months postoperatively. There was no relationship between preoperative lymphocyte, T-cell, helper-cell, suppressor-cell, or natural-killer cell number or natural-killer cytotoxicity and stage of disease. One to 3 months following surgery natural-killer cells had increased more than 50% from 218 to 325 cells/cmm (T = 2.07, P = 0.0459). Natural killer cytotoxicity increased proportionally. Lymphocytes, T cells, suppressor cells, and helper cells increased insignificantly. The results suggest that potentially curative excision of solid tumors in man is eventually followed by return of immune function reflected by increased numbers of natural-killer cells.
Verrucous carcinoma of the larynx is a distinct and uncommon variant of well-differentiated squamous cell carcinoma. By DNA hybridization techniques, we clearly demonstrated human papillomavirus (HPV-16-related) sequences in five patients with this neoplasm. In addition, HPV-16-related sequences were found in adjacent normal tissues. The DNAs from squamous cell carcinomas of the larynx were negative when hybridized to HPV-6, -11, or -16. Postirradiation anaplastic transformation of verrucous carcinoma has been described. We believe that radiotherapy should not be given unless the potential consequences are fully explained because of its potential to activate or alter HPV-16-related sequences.
Several keto phosphonates, phosphonoacetates , and dialkyl phosphonates containing (aryloxy)aryl groups were synthesized and evaluated for antiherpteic activity. Two of the most active compounds, 12 and 16, were evaluated topically in the mouse vaginal model against herpes simplex virus (HSV) type 2. Compound 16 exhibited an increased survival rate, as well as increased survival time. Evaluation of 16 in the guinea pig skin test against HSV-2 produced a reduction in virus titer, as well as in mean vesicle score.
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The effects of cold-stress and hibernation on bone dynamics in the femurs of hamsters were investigated using histometric analyses. Control animals were maintained at 27 degrees C for 90 days; experimental animals were kept at 5 degrees C and hibernated for 7, 15, 21, 50, or 90 days. Histometric analyses of cross sections indicated that bone diameter and cortical thickness at the femoral midshaft increased after 83 days of extreme cold and 7 days of hibernation but decreased significantly after 69 days of cold stress and 21 days of hibernation. Osteoporosis was evident although the number of osteons per unit area of bone increased during hibernation. An initial decrease in the number of non-Haversian longitudinal vessels per unit area of bone was seen in experimental animals which was apparently related to a corresponding reduction in cortical thickness. Lacunar area increased in these animals, suggesting that osteocytic osteolysis may be a significant mechanism for calcium regulation during hibernation.
The outcome of antidepressant drug treatment was measured in 200 patients, 145 seen in psychiatric out-patient clinics and 55 in general practice, after 4 weeks of therapy. The results of the 200 patients taken together suggested that prognosis was largely determined by factors dependent on the natural history of the disorder and that clinical symptoms were unimportant, but when the results for patients in each drug group were analysed separately symptoms were more important than natural history factors. We conclude that clinical symptoms are only important predictors of response to antidepressant drugs when the patients studied are homogeneous with regard to natural history factors, particularly duration of illness.
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Visual examination of the intensity of Procion dye in hamster femurs revealed that dye incorporation decreased during hibernation. Little or no dye was observed after hibernation lasting longer than 50 days. It seems that hibernation may be associated with increased bone resorption and a loss of bone matrix.
Negative selection with FUdR produced revertants from the transformed rat line 14B, which contains one insertion of the SV40 viral genome (Botchan, Topp and Sambrook, 1976). 14B contains nuclear T antigen, grows to a high density, grows in low serum and is anchorage-independent. The revertants fall into three classes with regard to viral DNA sequences: the SV40 DNA is retained; the SV40 DNA is retained but has undergone a deletion; and the SV40 DNA is lost, generating a cured cell. This heterogeneity is not a result of long-term passage. The revertants arise with a frequency of one in 8.4 X 10(5) cells after as few as 12 passages. All three classes of revertants are T antigen-negative, density-sensitive, more serum sensitive than 14B and anchorage-dependent. These data argue for a direct role of the functioning viral genome in the maintenance of the transformed state, and that with 14B, the phenotypes of transformation are not virus gene dosage-dependent.
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Pox-1, a mutant of Salmonella typhimurium, strongly channels P22 toward lysogeny. Viral DNA synthesis in this slow-growing mutant is delayed to a greater extent than viral protein synthesis. The relative enhancement of c2 repressor synthesis results in much higher repressor/DNA synthesis ratios in Pox-1 than in wild-type cells. This probably accounts for the high frequency of lysogenization.
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