Exact determination of the magnification factor for target lesions in a stereotactic frame.
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Cobalt Radioisotopes↗
Biomedical subjects
A Wu
Publications and source records attributed to A Wu.
Comments on dose measurements for a narrow beam in radiosurgery.
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Electrons↗
Influenza vaccination: a successful outpatient program.
We initiated a program to evaluate patient reasons for refusing immunization in an allergy clinic. A general medicine clinic was studied for comparison. For the Northwestern University Allergy Service (NUAS) there were five full-time salaried and seven voluntary physicians. In the general medicine clinic there was one part-time salaried physician. Four hundred eighty-eight NUAS patients and 48 general medicine patients were evaluated. Ninety-five percent of the patients agreed to vaccination. Egg allergy, the only valid contraindication to influenza vaccination, was reported by three (< 1%) patients. Transient mild symptoms consisting of fatigue, myalgias, rhinitis and/or diarrhea were reported in 20% of the patients who received vaccination. No severe systemic reactions were reported. No significant difference in the vaccination acceptance rate was noted between the subspecialty and primary care outpatient clinics. The importance of influenza immunization in patients with asthma and in other high-risk populations deserves emphasis, and high success rates are achievable when emphasized by physicians.
Aged↗
Resistance of MGH-U1 bladder cancer spheroids to vincristine.
We compared the cytotoxicity of vincristine in MGH-U1 human bladder cancer cells growing as exponential monolayer culture, spheroids and xenografts. Cells treated as spheroids were resistant to vincristine as determined by clonogenic survival and growth delay. The spheroid population had a smaller proportion of cells in G2 + M than monolayer cells. Cell derived from increasing depths of the spheroid viable rim had similar cell cycle distribution characteristics and sensitivity to vincristine. Prolonged treatment of spheroid did not increase vincristine cytotoxicity significantly. When cells derived from spheroids were treated as monolayers, the cytotoxicity was the same as that of cells maintained as monolayer cultures. The vincristine resistance observed in spheroids was also observed in xenografted tumours treated in vivo. Vincristine decreased the clonogenic survival of xenografted cells at in vivo doses which were greater than the LD10 for the mice. The in vitro cytotoxicity of the xenografted tumours at these lethal doses was similar to that of cells treated as spheroids. We conclude that vincristine resistance in spheroids may be attributed in part to the small proportion of cells traversing mitosis but not to the development of intrinsic resistance by passage through spheroid growth. Our results are consistent with cell cycle kinetics and limited penetration contributing to vincristine resistance in spheroids. The spheroid system can serve as a model of in vivo cytotoxicity for antineoplastic agents with cell cycle phase specificity such as vincristine.
Animals↗
Selective T-cell depletion with Ox-38 anti-CD4 monoclonal antibody prevents cardiac allograft rejection in rats.
New monoclonal antibodies directed to membrane molecules unique to lymphocyte subsets have provided the means to alter the immune response to alloantigens in a more selective fashion. This investigation demonstrates that monoclonal antibody-induced depletion of CD4 helper/inducer T lymphocytes before transplantation of a fully mismatched heart allograft allows permanent engraftment in rats without further immunosuppression. Five adult male ACI (RT1a) rats received cell-depleting doses of the mouse anti-rat CD4 monoclonal antibody, MRC Ox-38, for 1 month before undergoing heterotopic abdominal heart transplantation. No other immunosuppression was administered, and immunotherapy was discontinued the day of transplantation. After all five Lewis rat (RT1(1)) hearts were maintained free of rejection for more than 3 months, a second heterotopic transplant was performed, this time to the femoral vessels, using either fresh Lewis heart allografts (n = 3) or third-party, Brown-Norway (RT1n) hearts (n = 2). Histologic evaluation was performed 3 weeks later and revealed severe rejection of the femoral Brown-Norway grafts with no evidence of rejection in any of the femoral or original abdominal Lewis grafts. These results suggested that limited, pretransplant anti-CD4 immunotherapy allowed permanent engraftment of fully mismatched cardiac allografts in rats and conferred donor-specific unresponsiveness.
Abdomen↗
Effects of 5-fluorouracil and leucovorin in spheroids: a model for solid tumours.
We determined the cytotoxcity of 5FU alone or with leucovorin in MGH-U1 cells growing as monolayers or spheroids. The 5FU IC50 in spheroid and monolayers was 100 microM in both culture systems. The IC50 of 5FU and 5FU and 100 microM leucovorin in spheroids and monolayers was 100 microM and 50 microM, respectively. [H3]5 FU reached cells at all depths of the spheroid viable rim. Cells isolated from increasing depths of the spheroid viable rim demonstrated increasing resistance to 5FU. 5FU cytotoxicity is increased by leucovorin in monolayer but not spheroids, penetration is not limiting in 5FU cytotoxicity in spheroids and there is increasing resistance to 5FU in the viable rim.
Cell Division↗
A simple method of producing a monolayer of cervical cells for digital image processing.
A manual method of producing a monolayer of isolated and evenly distributed cervical epithelial cells has been developed for use in an automated digital image analysis system. The cervical scrape specimen is vortexed from the spatula into a solution of Mucosol. The suspension is filtered through a 10 micro nylon mesh to remove polys and debris and then syringed to disaggregate epithelial clumps. The cells are plated out on a Nuclepore filter. The filter is touched directly onto a glass microscopic slide to transfer cells, which are then fixed and stained in a routine manner. Cell counts reveal elimination of 92% polys, with only 2% loss of squamous cells.
Autoanalysis↗
The morphological changes of the endothelium to venous stasis as observed under the scanning electron microscope.
In this study using the pig, venous stasis is produced artificially by placing a pneumatic cuff around the hind leg of the anaesthetised animal and the cuff inflated intermittently. The period of stasis is three hours. The leg vein distal to the cuff is biopsied before and at intervals after the onset of stasis. The endothelium of the vein is examined under the scanning electron microscope. These findings suggest that venous stasis has a traumatic effect on the endothelium and cell injury is demonstrated within three minutes of the onset of stasis. With increasing period of stasis the endothelial cells are desquamated resulting in the exposure of the subendothelial basement membrane and collagen fibres. This is followed by aggregation of platelets and fibrin. It is postulated that the effect of venous stasis on the endothelium is a primary factor and may be important in the aetiology of clinical thrombogenesis.
Animals↗