Inability of cytoplasmic or nuclear androgen receptor content or distribution to distinguish benign from carcinomatous human prostate.

We used exchange saturation analysis at 15 degrees to quantitate total cytoplasmic and nuclear androgen receptor content of 70 patient specimens. Cytoplasmic androgen receptor contents (fmol/mg DNA) for eight specimens of clinically benign hyperplasia, 14 specimens of histologically hyperplastic prostate obtained at cystoprostatectomy, and carcinomatous and noncarcinomatous prostate obtained at radical prostatectomy for prostatic carcinoma, 48 specimens, respectively, were 830 +/- 165 (mean +/- S.E.), 890 +/- 445, 955 +/- 240, and 750 +/- 95. Nuclear androgen receptor contents of these same specimens, respectively, were 275 +/- 40, 235 +/- 30, 345 +/- 25, and 350 +/- 30; whereas, the values of the cytoplasmic/nuclear receptor content, respectively, were 3.25 +/- 0.55, 3.05 +/- 0.80, 2.50 +/- 0.50, and 2.80 +/- 0.40. Multiway analyses of variance of these cross-sectional data showed that there was no significant difference (p greater than 0.05) between group mean values. This result principally reflects the fact that the families of values for the four tissue groups were highly heterogenous with broad overlap. The results would not appear to be unduly influenced by carcinomatous epithelial cell content of the specimens, because cytoplasmic and nuclear androgen receptor content were not related to specimen carcinomatous epithelial cell content. Paired analyses of receptor content in carcinomatous and noncarcinomatous prostate specimens from the same prostate showed enhanced or unchanged receptor content in 58% (cytoplasmic) and 62% (nuclear) of specimens. Our studies show that cross-sectional analyses of androgen receptor content fail to distinguish carcinomatous prostate from noncarcinomatous prostate. However, paired analyses of these tissues from the same gland identify distinguishing differences. The clinical relevance of these observations remains to be examined.

Androgen regulation of androgen receptor content and distribution in the ventral and dorsolateral prostates of aging AXC rats.

Total androgen receptor content of ventral or dorsolateral prostate of intact, aged (730-740 day old) rats is decreased 50% when compared to intact, young mature (150-170 day old) rats. Treatment with exogenous testosterone increased ventral and dorsolateral prostate androgen receptor content per cell in aged rats to values identical to those of prostates of young mature rats. The increase in prostate receptor content was not attributable to testosterone mediated cellular hypertrophy or hyperplasia. At 24 hr post-orchiectomy ventral prostate cytoplasmic androgen receptors are depleted of endogenous androgen, without any decrease in number of receptors per cell, and nuclear androgen receptors are undetectable. During 30 to 60 min after a single 200 microgram testosterone injection, ventral prostate nuclear receptor content increased to the level of intact control rats without producing any reduction in total cytoplasmic androgen receptor content. Although dorsolateral prostate is devoid of cytoplasmic androgen receptor, the effects of orchiectomy and testosterone treatment upon nuclear androgen receptor are comparable to those seen in ventral prostate. These effects of orchiectomy and testosterone injection upon prostatic receptor content and distribution were identical in prostates of young and aged rats. Our studies show that receptor processing in prostates of young and aged rats does not involve a process by which nuclear receptor is derived by depletion of cytoplasmic receptor. Moreover, our studies of the effect of short-term (48 hr) exogenous testosterone treatment upon androgen receptor content in prostates of aged rats are the first demonstration that androgen receptor content may be enhanced independent of generalized androgen mediated anabolic effects in prostate.

In vivo biodistribution of a radiolabeled blood substitute: 99mTc-labeled liposome-encapsulated hemoglobin in an anesthetized rabbit.

Liposome-encapsulated hemoglobin (LEH) is an erythrocyte substitute that is a potential resuscitative fluid for the in vivo delivery of oxygen. We have noninvasively imaged radiolabeled LEH in vivo with technetium-99m (99mTc) to study the biodistribution in an anesthetized rabbit. Rabbits (2.5 kg, n = 8) were infused with 30 ml of LEH (200 mg of phospholipid, 2.5 g of hemoglobin per kg of body weight) and imaged with a gamma camera continuously for 2 hr. At 20 hr postinfusion, the animals were imaged again and sacrificed; the organs were weighted and their radioactivity was determined for autopsy organ distribution. Organ uptake from the images was corrected for organ-associated blood pool, which was determined by infusion of 99mTc-labeled rabbit erythrocytes. Blood pool and decay-corrected biodistribution data reveal the kinetics of LEH distribution, with an initial rapid uptake by the liver, 8% at 30 min and 15% at 2 hr. The spleen accumulates less LEH initially, 3% at 30 min and 7% at 2 hr, with an apparent linear uptake of LEH over this time period. Image biodistribution data was also validated at 20 hr by tissue sampling. At 20 hr postinfusion, autopsy biodistribution data reveals approximately 42.6% of the total counts remaining in the blood, 15.4% in the liver, 18.1% in spleen, 3.2% in the lungs, 2.4% in muscle, 1.6% in urine, and trace levels in the kidney, brain, and heart (less than 1%). There is no evidence of hemoglobin release from LEH or kidney dysfunction (normal creatinine and blood urea nitrogen) at any time over the course of the study.

Creatine kinase and lactate dehydrogenase: stability of isoenzymes and their activity in stored human plasma and prostatic tissue extracts and effect of sample dilution.

We examined the effect of storing human plasma or extracts of prostate at -90 degrees C on the activity of creatine kinase and lactate dehydrogenase and isoenzyme distribution. Enzyme activities were unaltered during storage for as long as six weeks. If these preparations were thawed only once at 2 to 4 degrees C, they could be stored for as long as 165 days at -90 degrees C with no change in isoenzyme distribution. Inexplicably, apparent isoenzyme distribution of prostatic lactate dehydrogenase was sensitive to sample dilution, whereas the isoenzyme distribution of lactate dehydrogenase in plasma was not. Our observations emphasize the importance of validating details of analytical protocols that are to be used for quantification of new types of specimens.

Polyethylene glycol-modified liposome-encapsulated hemoglobin: a long circulating red cell substitute.

A major obstacle in the development of red cell substitutes has been overcoming their short circulation persistence. In this study, distearoyl phosphoethanolamine polyethylene glycol 5000 (PEG-PE) (10 mol%) was added to the formulation of liposome-encapsulated hemoglobin (LEH) to decrease reticuloendothelial system uptake and prolong LEH circulation persistence. PEG-LEH was radiolabeled with technetium-99m, infused into rabbits (25% of blood pool at 1 ml/min) (n = 5), and monitored by scintigraphic imaging at various times out to 48 h. At 48 h, animals were sacrificed, and tissue samples were collected for counting in a scintillation well counter. Tissue distribution data at 48 h revealed that 51.3 +/- 3.4% of the technetium-99m-PEG-LEH remained in circulation, a greater than 3-fold increase in the circulation half-life compared with circulation half-lives previously reported for non-PEG-containing LEH formulations. The liver had the greatest accumulation at 48 h (12.7 +/- 0.7%), followed by bone marrow (6.2 +/- 0.1%), whereas the spleen had only 1.4 +/- 0.2%. The addition of PEG-PE to the LEH formulation greatly prolongs the circulation persistence of LEH and represents a significant step in the development of red cell substitutes with prolonged oxygen delivery.