Dose Of 32P Research Articles

Application of a kinetic model to describe phosphorus metabolism in pigs fed a diet with a microbial phytase

SUMMARYThe objective of the current study was to apply the Vitti–Dias model to investigate phosphorus (P) metabolism in growing pigs fed a diet supplemented with microbial phytase. The basal diet contained maize, defatted rice bran, vegetable oil, soybean meal, limestone, salt and a vitamin and mineral mix. There was no inorganic P in the diet and phytase was added at levels of 253, 759, 1265 and 1748 phytase units (PU)/kg of feed. The compartmental model included four pools of P: (1) gut lumen, (2) plasma, (3) bone and (4) soft tissue. A single dose of32P was administered, and specific radioactivity was measured in plasma, faeces, bone and soft tissue (muscle, heart, liver and kidney) at different times post-dosing for calculation of P flows between pools. Total P absorbed showed a negative relationship with total P excreted in faeces and was strongly correlated with bone P retention, suggesting that absorbed P was channelled to bone to address its physiological growth. Average efficiency of metabolic utilization of absorbed P was estimated to be 0·94, with 0·52 g/g of total net P balance being accreted in bone and the rest in soft tissue (including muscle and some vital organs). The Vitti–Dias model provided suitable representation of P interchange between compartments (in particular, flows between gut and plasma and partitioning of available P between bone and soft tissue), resulting in estimates of P flows comparable with values calculated from balance data.

Determinants of model of renarrowing after beta radiation for in-stent restenosis

It is unknown whether model of renarrowing after β-radiation for in-stent restenosis (ISR) is influenced by the type of geographic miss (GM). Methods In 166 ISR treated with Galileo, serial quantitative coronary angiographic analysis was done. Minimal lumen diameters and lengths were measured for (1) stent, (2) peri-stent subsegments subjected to angioplasty with/without irradiation, and (3) irradiation margins. GM was defined as: (Type 1) edge injury within the 32P source dose fall-off: 2.0 mm inside and outside the source end marker or (Type 2) overt, nonirradiated injury: beyond the outer 2.0-mm long dose fall-off zone. Results Restenosis rate was 28.3% at 8.9 ± 4.5 months with 60% located exclusively outside the stent. Type 1 GM was present in 24.7% of proximal edges, whereas Type 2 in 18.1%. Respective percentages for distal edges were 23.5% and 15.7%. Regardless of presence and type of GM, significant late lumen loss occurred only outside the stent. However, the biggest late lumen loss at the proximal edge was induced by the Type 1 GM (0.65 ± 0.79, p < 0.001), while proximal Type 2 GM was not associated with edge renarrowing (−0.04 ± 0.48, p = NS). Both reference lumen diameter and proximal Type 1 GM influenced restenosis independently (OR 0.47; 95%CI 0.24–0.90; p = 0.023 and OR 2.46; 95%CI 1.12–5.40; p = 0.025). Conclusions Regardless of presence and type of geographic miss, late lumen loss after β-radiation occurs only outside the stent. However, injury within the proximal 32P dose fall-off but not overt edge injury is associated with the biggest late lumen loss at the respective edge, triggering recurrent restenosis.

Endovascular brachytherapy in coronary arteries: the Rotterdam experience

Purpose: The use of endovascular coronary brachytherapy to prevent restenosis following percutaneous transluminal coronary angioplasty (PTCA) began in April 1997 at the Department of Interventional Cardiology of the Thoraxcenter at the University Hospital of Rotterdam. This article reviews the more than 250 patients that have been treated so far. Methods and Materials: The Beta-Cath™ System (Novoste), a manual, hydraulic afterloader with 12 90Sr seeds, was used in the Beta Energy Restenosis Trial (BERT-1.5, n=31), for compassionate use ( n=25), in the Beta-Cath System trial ( n=27) and in the Beta Radiation in Europe (BRIE, n=14). Since the Beta-Cath™ System has been commercialized in Europe, 57 patients have been treated and registered in RENO (Registry Novoste). In the Proliferation Reduction with Vascular Energy Trial (PREVENT), 37 patients were randomized using the Guidant-Nucletron remote control afterloader with a 32P source wire and a centering catheter. Radioactive 32P coated stents have been implanted in 102 patients. In the Isostent Restenosis Intervention Study 1 (IRIS 1), 26 patients received a stent with an activity of 0.75–1.5 μCi, and in the IRIS 2 (European 32P dose response trial), 40 patients were treated with an activity of 6–12 μCi. In two consecutive pilot trials, radioactive stents with non-radioactive ends (cold-end stents) and with ends containing higher levels of activity (hot-end stents) were implanted in 21 and 17 patients, respectively. Results: In the BERT-1.5 trial, the radiation dose, prescribed at 2 mm from the source train (non-centered), was 12 Gy (10 patients), 14 Gy (10 patients) and 16 Gy (11 patients). At 6-month follow-up, 8 out of 28 (29%) patients developed restenosis. The target lesion revascularization rate (TLR) was 7 out of 30 (23%) at 6 months and 8 out of 30 (27%) at 1 year. Two patients presented with late thrombosis in the first year. For compassionate use patients, a restenosis rate (RR) of 53% was observed. In the PREVENT trial, 34 of 37 patients underwent an angiographic 6-month follow-up. The doses prescribed at 0.5 mm depth into the vessel wall were 0 Gy (8), 28 Gy (9), 35 Gy (11) and 42 Gy (8). TLR was 14% in the irradiated patients and 25% in the placebo group. One patient developed late thrombosis. In the IRIS 1 trial, 23 patients showed an RR of 17% (in-stent). In the IRIS 2 trial, in-stent restenosis was not seen in 36 patients at 6-month follow-up. However, a high RR (44%) was observed at the stent edges. Conclusions: The integration of vascular brachytherapy in the catheterization laboratory is feasible and the different treatment techniques that are used are safe. Problems, such as edge restenosis and late thrombotic occlusion, have been identified as limiting factors of this technique. Solutions have been suggested and will be tested in future trials.

Treatment of Polycythemia Vera: Use of 32P Alone or in Combination With Maintenance Therapy Using Hydroxyurea in 461 Patients Greater Than 65 Years of Age

AbstractDespite myelosuppression, polycythemic (PV) patients greater than 65 years of age have a high risk of vascular complications, and the leukemic risk exceeds 15% after 12 years. Is the addition of low-dose maintenance treatment with hydroxyurea (HU) after radiophosphorus (32P) myelosuppression able to decrease these complications? Since the end of 1979, 461 patients were randomized to receive (or not) low-dose HU (5 to 10 mg/kg/d), after the first 32P-induced remission, and were observed until death or June 1996. Maintenance treatment very significantly prolonged the duration of 32P-induced remissions and reduced the annual mean dose received to one-third. However, despite this maintenance, 25% of the patients had an excessive platelet count and the rate of serious vascular complications was not decreased, except in the most severe cases with short-term relapse of polycythemia. Furthermore, the leukemia rate was significantly increased beyond 8 years and a significant excess of carcinomas was also observed. The continuous use of HU did not decrease the risk of progression to myelofibrosis (incidence of 20% after 15 years). Life expectancy was shorter (a median of 9.3 years v 10.9 years with 32P alone), except in the most severe cases (initial 32P-induced remission lasting <2 years) in which maintenance treatment moderately prolonged the survival by reducing the vascular risk. In most cases of PV, in which the duration of the first 32P-induced remission exceeded 2 years, the introduction of HU maintenance did not reduce the vascular risk. Although it considerably decreased the mean dose of 32P received, HU maintenance therapy significantly increased the leukemia and cancer risks and reduced the mean life expectancy by 15%. However, in cases with more rapid recurrence, the introduction of maintenance treatment reduced the vascular risks and moderately prolonged survival. The use of HU as a maintenance therapy is therefore only justified in this situation.

Survival and risk of leukaemia in polycythaemia vera and essential thrombocythaemia treated with oral radiophosphorus: Are safer drugs available?

For 366 patients with polycythaemia vera (PV) or essential thrombocythaemia (ET) diagnosed 1971-1990, oral administration of 32-P was used as myelosuppressive treatment. Retreatment was not restricted to any defined interval and the number of treatments or the total dose were not limited. For 107 patients, follow-up was > 10 years. 15 of these presented with life-threatening occlusive vascular symptoms and their survival was short. For the remaining 92 patients 5-yr survival was not significantly worse than for a Swedish population matched for age and sex. Survival at 10 yr was lower, 51% versus 66% expected. Acute myeloid leukaemia (AML) was diagnosed in 11 of the 107 patients (10.3%). In the whole material of 366 patients, 17 have developed AML with a median time of 8.5 yr from start of treatment. There was a maximum incidence of 4% per yr after 8-12 yr. Later, the incidence decreased. The median annual dose of 32-P for the AML patients was 100 MBq and was not significantly larger than for a matched control group surviving without AML, 96 MBq. The results are compared with reports on PV or ET patients treated with busulphan (Bu) or hydroxyurea (HU). With comparable periods of follow-up there are no indications that an adequate myelosuppression with oral 32-P will be associated with shorter survival or higher incidence of AML than treatment with Bu or HU. It is concluded that, for the time being, oral administration of 32-P is an acceptable standard treatment in PV and ET.

Experimental determination of 32P dose backscatter factors at and near soft-tissue boundaries.

Beta-ray dose backscatter factors with respect to soft tissue were measured using an extrapolation chamber. The beta-ray dose backscatter factor is a measure of the change effected in absorbed dose to a soft-tissue medium when part of the medium is replaced by a material other than soft tissue (i.e., a scatterer); the source is located at the boundary between the two media. The dependencies of backscatter factor on scatterer atomic number and on source geometry are investigated, and the variation of backscatter factor with distance from the boundary is determined. For a 32P point source, backscatter factors with respect to Mylar, a soft-tissue substitute, at 0.55 mg/cm2 from the boundary, are, 29.65[0.12]%, 31.07[0.24]%, 19.30[0.48]%, 16.27[0.35]%, 5.46[0.11]% and -26.44[0.02]% for bismuth, tungsten, cadmium, copper, aluminum, and air scatterers, respectively. Backscatter factors measured for a 32P planar source are generally smaller than those for a point source. The variation of backscatter factor with distance from the boundary is well represented analytically by sums of exponentials. Therefore, the rate of decrease of backscatter factor with distance can be specified by a relaxation length, defined as the depth through which the backscatter factor is reduced by 1/e, where e is the base of the natural logarithm. For example, with a 32P planar source, relaxation lengths in Mylar are 588[7] mg/cm2 and 238[2]mg/cm2 for bismuth and aluminum scatterers, respectively. Qualitative interpretation of backscatter factor depth profiles is presented. In addition, the variations of backscatter factor with scatterer atomic number and with source geometry are discussed with reference to existing experimental findings on beta particle reflection.

Beta-radiation from tracer doses of 32P induces massive apoptosis in a Burkitt's lymphoma cell line.

The induction of extensive apoptosis by tracer doses of 32P has the potential to invalidate the results of biochemical studies using this and possibly other radioactive isotopes.

Adjuvant Therapy in Stage I and Stage II Epithelial Ovarian Cancer

YOUNG, ROBERT C.; WALTON, LESLIE A.; ELLENBERG, SUSAN S.; HOMESLEY, HOWARD D.; WILBANKS, GEORGE D.; DECKER, DAVID G.; MILLER, ALEXANDER; PARK, ROBERT; MAJOR, FRANCIS JR. Author Information

Adjuvant therapy in stage I and stage II epithelial ovarian cancer. Results of two prospective randomized trials

About a third of patients with ovarian cancer present with localized disease; despite surgical resection, up to half the tumors recur. Since it has not been established whether adjuvant treatment can benefit such patients, we conducted two prospective, randomized national cooperative trials of adjuvant therapy in patients with localized ovarian carcinoma (International Federation of Gynecology and Obstetrics Stages Ia to IIc). All patients underwent surgical resection plus comprehensive staging and, 18 months later, surgical re-exploration. In the first trial, 81 patients with well-differentiated or moderately well differentiated cancers confined to the ovaries (Stages Iai and Ibi) were assigned to receive either no chemotherapy or melphalan (0.2 mg per kilogram of body weight per day for five days, repeated every four to six weeks for up to 12 cycles). After a median follow-up of more than six years, there were no significant differences between the patients given no chemotherapy and those treated with melphalan with respect to either five-year disease-free survival (91 vs. 98 percent; P = 0.41) or overall survival (94 vs. 98 percent; P = 0.43). In the second trial, 141 patients with poorly differentiated Stage I tumors or with cancer outside the ovaries but limited to the pelvis (Stage II) were randomly assigned to treatment with either melphalan (in the same regimen as above) or a single intraperitoneal dose of 32P (15 mCi) at the time of surgery. In this trial (median follow-up, greater than 6 years) the outcomes for the two treatment groups were similar with respect to five-year disease-free survival (80 percent in both groups) and overall survival (81 percent with melphalan vs. 78 percent with 32P; P = 0.48). We conclude that in patients with localized ovarian cancer, comprehensive staging at the time of surgical resection can serve to identify those patients (as defined by the first trial) who can be followed without adjuvant chemotherapy. The remaining patients with localized ovarian cancer should receive adjuvant therapy, and with adjuvant melphalan or intraperitoneal 32P should have a five-year disease-free survival of about 80 percent.

Adjuvant Therapy in Stage I and Stage II Epithelial Ovarian Cancer

About a third of patients with ovarian cancer present with localized disease; despite surgical resection, up to half the tumors recur. Since it has not been established whether adjuvant treatment can benefit such patients, we conducted two prospective, randomized national cooperative trials of adjuvant therapy in patients with localized ovarian carcinoma (International Federation of Gynecology and Obstetrics Stages Ia to IIc). All patients underwent surgical resection plus comprehensive staging and, 18 months later, surgical re-exploration. In the first trial, 81 patients with well-differentiated or moderately well differentiated cancers confined to the ovaries (Stages Iai and Ibi) were assigned to receive either no chemotherapy or melphalan (0.2 mg per kilogram of body weight per day for five days, repeated every four to six weeks for up to 12 cycles). After a median follow-up of more than six years, there were no significant differences between the patients given no chemotherapy and those treated with melphalan with respect to either five-year disease-free survival (91 vs. 98 percent; P = 0.41) or overall survival (94 vs. 98 percent; P = 0.43). In the second trial, 141 patients with poorly differentiated Stage I tumors or with cancer outside the ovaries but limited to the pelvis (Stage II) were randomly assigned to treatment with either melphalan (in the same regimen as above) or a single intraperitoneal dose of 32P (15 mCi) at the time of surgery. In this trial (median follow-up, greater than 6 years) the outcomes for the two treatment groups were similar with respect to five-year disease-free survival (80 percent in both groups) and overall survival (81 percent with melphalan vs. 78 percent with 32P; P = 0.48). We conclude that in patients with localized ovarian cancer, comprehensive staging at the time of surgical resection can serve to identify those patients (as defined by the first trial) who can be followed without adjuvant chemotherapy. The remaining patients with localized ovarian cancer should receive adjuvant therapy, and with adjuvant melphalan or intraperitoneal 32P should have a five-year disease-free survival of about 80 percent.

Influence of High Dietary Aluminum on Performance and Phosphorus Bioavailability in Dairy Calves

Sixteen male intact Holstein calves averaging 72kg and 64 d of age were used to study the effects of high dietary Al on calf performance and P bioavailability. The main effects were two concentrations of added aluminum (0 and .20% Al) and two of added P (0 and .22% P). The basal diet contained, by analysis, .132% P, .74% Ca, and .021% Al. The calves were assigned to four treatment groups balanced according to body weight. The four treatments were 1) normal P, low Al; 2) low P, low Al; 3) low P, high Al; and 4) normal P, high Al. Calves had ad libitum access to their respective diets for 7 wk. Metabolism of a single oral 32P dose was determined during wk 6. The adverse effects of high dietary Al include a 17% reduction in feed intake and a 47% reduction in body weight gains. Alkaline phosphatase and plasma glutamic oxaloacetate transaminase activities increased in calves receiving the high Al diets. A negative balance of P and Ca was noted in the calves fed high concentrations of Al. Apparent absorption of 32P was reduced (37%) in calves fed diets high in Al (44% of dose vs. 69%). Urinary excretion of 32P was not affected by dietary Al concentrations. Calves fed the low P (deficient) diet showed significant reductions in feed intake, weight gain, serum inorganic P, bone ash, and P content of bone. Dietary P did not significantly affect 32P absorption. Adding .20% dietary Al severely affects P metabolism and performance of young growing calves.

The treatment of essential thrombocythaemia with radioactive phosphorus

The major complications of essential thrombocythaemia include haemorrhage and thrombosis, events which are related to the level of the abnormal platelet count. We report here on the use of radioactive phosphorus (32P) in eight patients with essential thrombocythaemia. Two patients required multiple injections of 32P to control platelet count, and there was no reduction in the rate of fall of platelets with each injection. Three patients required chemotherapy for persistent thrombocythaemia despite multiple doses of 32P. No clinical or haematological characteristics could be identified for those patients whose disease was difficult to control. Radioactive phosphorus is a safe and effective method to control platelet counts in patients with essential thrombocythaemia.

Colloidal Chromic Phosphate 32P Synovectomy in Antigen-Induced Arthritis in the Rabbit

Radioisotopes have been employed in the therapy of chronic arthritis, in particular, rheumatoid arthritis for many years. A variety of isotopes have been popularized, and in the last ten years a colloidal solution of radioactive chromic phosphate 32P has been in use apparently with equivalent efficacy to others such as 169erbium, 90yttrium, and 165dysprosium. No controlled studies on this modality have been reported and few animal studies were found. The efficacy of therapeutic doses of 32P as a medical synovectomy and its effect on rabbit joints with antigen-induced arthritis were observed in 62 arthritic knee joints in 31 adult rabbits treated on one side with 0.1 microCi of 32P, the opposite serving as control. The animals were observed over a period of 11 months and examined by histologic and biochemical means. The synovium showed no evidence of radiation necrosis in treated joints. Cartilage of treated and control joints showed similar changes consistent with chronic arthritis, persistent synovitis, progressive chondrocyte degeneration, and decreased matrix metachromasia. The radiosynovectomy had neither removed synovium nor protected the cartilage. Its efficacy in humans is therefore questionable.

Changes of the blood lymphocyte subpopulations and their functions following 131I treatment for nodular goitre and 32P treatment for polycythemia vera.

The blood lymphocyte population was examined in 34 patients who were treated with 131I for toxic or atoxic nodular goitre. One to three doses of 300-550 MBq of 131I were administered at 1-week intervals. Lymphocyte counts were found to be significantly reduced at both 1 and 6 weeks after treatment. This decrease was accompanied by a changed composition of the lymphocyte subpopulations. The frequency of lymphocytes expressing membrane receptors for C'3 (EAC-rosette forming cells) was significantly reduced at 1 and 6 weeks following 131I administration. At 6 weeks there was a small but statistically significant increase of the frequency of T cells as identified by Leu 1 monoclonal antibodies. This was essentially due to an increased proportion of helper/inducer T cells as identified by Leu 3 monoclonals. 131I treatment also decreased the capacity of lymphocytes to secrete immunoglobulins (Ig) when stimulated with pokeweed mitogen (PWM). The greatest effect was observed for IgM. Secretion of IgG and IgA were less reduced. Mitogenic stimulations of lymphocytes with phytohemagglutinin (PHA) and concanavalin A were not significantly changed. It is concluded that these findings, with the exception of mitogen reactivity, are largely similar to those occurring following external radiation therapy for cancer. It is suggested that blood lymphocytes passing through the continuously irradiated gland are damaged mainly by beta-rays. The effect of 32P treatment on the blood lymphocyte population was examined in 16 patients with polycythemia vera. Before treatment the lymphocyte counts were within the normal range but the expression of certain membrane structures, as identified by monoclonal antibodies against total T cells (Leu 1 and 4), helper/inducer (Leu 3) and suppressor/cytotoxic T cells (Leu 2), were slightly decreased. Moreover, mitogenic responses of the lymphocytes to PHA and PWM-induced Ig secretion were impaired. Following a single oral dose of 32P (150-305 MBq), which normalized the production of erythrocytes and/or platelets, the blood lymphocyte counts were reduced by approximately 40 per cent 12 weeks after treatment. Examination of subsets demonstrated that the proportion of B-cells, as identified by B1 monoclonal antibodies, was decreased by the highest relative extent. On the other hand, lymphocytes expressing the above-mentioned T cell markers were somewhat increased. 32P treatment markedly increased PHA reactivity but it further reduced PWM-induced Ig secretion. The latter observation was in agreement with the finding that serum concentrations of Ig were reduced after treatment.

Effect of 32P treatment for polycythaemia vera on blood lymphocyte subpopulations and their functions.

The influence of 32P treatment on the blood lymphocyte population was examined in 16 patients with polycythaemia vera who had not previously been treated with cytotoxic drugs or irradiation. Before treatment the lymphocyte counts were within the normal range but the expression of certain membrane structures, as detected by monoclonal antibodies directed against total T cells (CD 3 and 5), helper/inducer (CD 4) and suppressor/cytotoxic T cells (CD 8), were slightly reduced. In addition, mitogenic responses of the lymphocytes to PHA and PWM-induced Ig secretion were severely impaired. Following a single oral dose of 32P (150-305 MBq), which was shown to normalize the production of erythrocytes and/or platelets, the blood lymphocyte counts were reduced by approximately 40% 12 wk after treatment. Subset analysis showed that the proportion of B cells, as identified by monoclonal antibodies (CD 20), was reduced to the highest relative extent. On the other hand, lymphocytes expressing the above T cell markers were somewhat increased. 32P treatment sharply increased PHA reactivity but it further reduced PWM-induced Ig secretion. The latter observation was in line with the finding that serum concentrations of Ig were reduced following treatment.

9 - Radioisotopes in the Treatment of Ovarian Cancer

Ovarian cancer, currently, is the leading cause of death from malignancies arising in the female genital tract. Investigators and collaborative groups are focusing on this problem in an attempt to improve patient survival. The material reviewed has attempted to gather the data that relate to the use of radioisotopes in the treatment of ovarian cancer. The conclusions reached from this review are: Dose. The initial therapeutic dose of 198Au was empirically determined by Muller. This empirically determined dose was then used to estimate a dose of 32P, based on certain assumptions about these radiocolloids that have been shown to be erroneous. It would appear that the administered dose of 100-150 mCi of 198Au yields a significantly greater tissue dose than 10-15 mCi of 32P. Complications. Complications associated with 198Au are a result of a possibly excessive dose, delivered over a shorter period of time, with a significant gamma component. It is clear that in greater than 99 per cent of disintegrations each beta particle is associated with a gamma component. Distribution, dose distribution, and dose rate. These three critical factors have recently been evaluated for intraperitoneal 32P. It would appear that distribution is non-uniform, and thus dose distribution is not homogeneous, and that dose rate is low and may be ineffective in controlling ovarian cancer. Results of treatment. It would appear from a review of the literature that no prospective randomized well-controlled study as indicated the effectiveness of 32P over other treatment modalities. There is only circumstantial evidence for its effectiveness. The clinical applicability of 32P in the treatment of Stage I ovarian cancer, as part of a treatment protocol, awaits the results of well controlled prospective clinical trials.

Secondary treatment of polycythemia rubra vera with 6-thioguanine.

6-thioguanine, an antimetabolite not potentiated by allopurinol, has been used in the treatment of 29 patients with polycythemia vera. All but two of the patients had been treated previously by venesection and/or radioactive phosphorus (32p) and/or alkylating agents. The usual dose was 40-160 mg daily alternate weeks according to individual response. The treatment period varied from 6-66 months (mean, 31 months). Of 27 evaluable patients 24 (89%) responded to treatment and at one year there was a significant fall in all blood count parameters. Seven patients relapsed while on treatment and four were withdrawn because of side effects. 6-thioguanine merits further evaluation in the management of polycythemia vera, particularly in those patients who have received large cumulative doses of 32p and/or alkylating agents and in whom an alternative mode of therapy is desirable.

Effects of injection volume on the tissue dose, dose rate, and therapeutic potential intraperitoneal 32p.

Increasing the injection volume had no significant long-term effect on the distribution or tissue dose of intraperitoneal 32P in New Zealand white rabbits. Further, the range of doses and dose rates observed in the rabbit had little effect in vitro against either a human ovarian cancer line or an established Chinese hamster cell line. Demonstrable kill of human ovarian cancer cells was achieved, however, for initial 32P dose rates of 11 and 22 rad/h (0.11 and 0.22 Gy/h). From these results, it is estimated that administered 32P activities ranging from about 75-150 mCi (2.8-5.6 GBq) would be required for significant tumoricidal effects in ovarian cancer patients.

Evaluation of radioactive phosphorus in the palliation of metastatic bone lesions from carcinoma of the breast and prostate.

Radioactive phosphorus effected substantial palliation of intractable bone pain in 17 of 33 (51.5%) women with metastatic carcinoma of the breast and in 14 of 15 (93.3%) men with metastatic carcinoma of the prostate. No significant difference in the overall response rate was found between androgen and parathormone priming prior to radiophosphorus therapy. The degree of response was not dependent on total dose of 32P within the range of 9--18 mCi (333--666 MBq). Myelosuppression was a transient complication in 9 of 33 patients with metastatic breast carcinoma and in 7 of 15 patients with metastatic prostate carcinoma. Symptomatic hypercalcemia was an infrequent complication of radiophosphorus therapy irrespective of the priming regimen.

Radiolabeling Heliothis virescens1 Eggs by 32P Injection of Adult Females2

A technique is described for radiolabeling Heliothis (F.) eggs by injecting adult females with a pulse dose of 32P. An expected DPM/egg can be predicted from various doses by the following equations: log Ħ = —4.99 + 1.19 (log X), log Ŷ = —5.67 + 1.27 (log X) and log Ŷ = —5.55 + 1.25 (log X) for 72, 96, and 120 h, respectively. The pupal weight of H. virescens was unrelated to the amount of label incorporated into eggs subsequently laid by the adults. Larvae of the predator, Chrysopa carnea (Stephens), did not distinguish between normal and 32P labeled eggs of the same age.