High-affinity specific [3H]tamsulosin binding to alpha 1-adrenoceptors in human prostates with benign prostatic hypertrophy

The binding of a novel radioligand, [3H]tamsulosin, to human prostatic membranes with benign prostatic hypertrophy (BPH) has been characterized. [3H]Tamsulosin rapidly associated with its binding sites in human prostatic membranes with BPH, and the binding reached steady state by 30 min at 25 degrees C. The rate constants for association and dissociation of [3H]tamsulosin binding were calculated to be 0.21 +/- 0.05/nM per minute and 0.01 +/- 0.004/min, respectively. The specific binding of [3H]tamsulosin in human prostatic membranes was saturable and of high affinity (Kd = 0.04 +/- 0.01 nM). The density of [3H]tamsulosin-binding sites (Bmax) was 409 +/- 28 fmol/mg protein. The Kd and Bmax values for [3H]tamsulosin binding in human prostates were significantly lower than those for [3H]prazosin binding. [3H]tamsulosin binding was remarkable for its significantly lower degree of nonspecific binding. Six alpha-adrenoceptor antagonists competed with [3H]tamsulosin for the binding sites in the rank order: tamsulosin > WB4101 > prazosin > S-(+)-isomer > naftopidil > yohimbine. The binding affinities (pKi) of these antagonists for [3H]tamsulosin binding in human prostates closely correlated with their pharmacological potencies (pA2) in prostates. In conclusion, [3H]tamsulosin selectively labels alpha 1-adrenoceptors in human prostates, and thus may become a useful radioligand for the further analysis of these receptors.

Angiotensin II receptor subtypes in bovine and human ventricular myocardium

Angiotensin II (AII) binding sites in bovine and human ventricular myocardium were characterized by a radioreceptor assay. The specific binding of [125I]AII to myocardial membranes appeared to be saturable, and it was of high affinity with apparent dissociation constants of 1.60 nM (bovine) and 1.09 nM (human). The Bmax values were 39.7 fmol/mg protein (bovine) and 6.07 fmol/mg protein (human). Both losartan (angiotensin type 1 receptor subtype selective antagonist) and PD123177 (the angiotensin type 2 receptor subtype selective antagonist) inhibited specific [125I]AII binding to bovine myocardium, and their Hill coefficients were less than unity. Nonlinear least-squares regression analysis has suggested the existence of two populations of [125I]AII binding sites that have high and low affinity for losartan or PD123177. The relative proportions of high- and low-affinity sites for losartan in bovine myocardium were 68% and 32%, and those for PD123177 were 33% and 67%, respectively. On the other hand, specific [125I]AII binding in human myocardium was inhibited by losartan with much lower affinity and also by PD123177 with higher affinity, compared with bovine myocardium. The Hill coefficients for both drugs were close to one. Dithiothreitol enhanced specific [125I]AII binding to bovine myocardium in the presence of losartan, but it reduced [125I]AII binding in the presence of PD123177. This agent markedly enhanced specific [125I]AII binding to human myocardium. Thus, it is possible that bovine myocardium has both angiotensin type 1 receptor and the angiotensin type 2 receptor subtypes of AII receptors whereas human myocardium has predominantly the angiotensin type 2 receptor subtype.

Implanted bone particles induce osteoclast development in the presence of osteoblast lineage cells

We implanted mineral-containing bone particles (BPs) in rats to investigate the involvement of osteoblast lineage cells in osteoclast development in vivo. BPs were implanted in subcutaneous regions on calvaria or artificial defects of calvaria, with or without adjacent parathyroid glands prepared from other rats. The structural characteristics of multinucleated giant cells (MGCs) induced by the BPs were investigated. The MGCs induced by subcutaneously implanted BPs showed membrane ruffling at the basolateral site, but not at the apical site, regardless of whether parathyroid glands were also implanted. In contrast, the MGCs induced by intraosseously implanted BPs showed the characteristics of osteoclasts, i.e., ruffled borders at the apical sites, clear zone, vacuoles, many mitochondria, and scattered rough endoplasmic reticulum. When BPs and parathyroid glands were implanted in bone defects, the number of MGCs was increased compared to that induced by BPs only. These MGCs showed the typical characteristics of active osteoclasts, including developed ruffled borders and stacks of Golgi succules. The number of osteoclasts was also investigated quantitatively by counting the numbers of MGCs positive and negative for tartrate-resistant acid phosphatase. In intraosseous implantation, MGCs with the characteristics of osteoclasts were observed close to osteoblastic cells characterized by developed rough endoplasmic reticulum. These results indicate that the osteoclasts were not induced solely by the subcutaneously implant BPs, but required osteoblast lineage cells for development.

Comparative study on alpha 1-adrenoceptor antagonist binding in human prostate and aorta

1. Specific binding of [3H]-prazosin in prostatic and aortic membranes of humans was saturable and of high affinity (prostate: apparent dissociation constant, Kd = 0.35 +/- 0.03 nmol/L; aorta: Kd = 0.26 +/- 0.03 nmol/L). The density of [3H]-prazosin binding sites (Bmax) for prostate and aorta was 546 +/- 31 and 61.6 +/- 1.6 fmol/mg protein, respectively. 2. Prazosin, YM617, naftopidil and urapidil competed with [3H]-prazosin for the binding sites in a dose-dependent manner in the prostate and aorta of humans. The binding affinities of these antagonists in both tissues were compared, based on the inhibition constant, Ki. Both prazosin and urapidil showed similar affinity to [3H]-prazosin binding sites in human tissue, whereas YM617 and naftopidil showed approximately a 12 and two times higher affinity, respectively, to alpha 1-adrenoceptor sites of prostate than aorta. 3. The chloroethylclonidine treatment reduced partially the Bmax values for specific [3H]-prazosin binding in the prostate and aorta of humans with little effect on the Kd values. 4. These data suggest that YM617 is a relatively selective antagonist of human prostatic alpha 1-adrenoceptors.

Pharmacokinetics of amlodipine and its occupancy of calcium antagonist receptors

We characterized the occupancy of dihydropyridine (DHP) calcium antagonist receptors by amlodipine in spontaneously hypertensive rats (SHR) in relation to its pharmacokinetics. Oral administration of amlodipine (10 mg/kg) in SHR produced a significant (20-70%) decrease in the number of specific (+)[3H]PN 200-110 binding sites in cardiac tissues 0.5-18 h later, and the effect was greatest 3 h later. In these rats, there was little change in cerebral cortical (+)[3H]PN 200-110 binding. Occupancy of cardiac calcium antagonist receptors after oral administration of amlodipine correlated well with its plasma concentration. In vitro blockade of cardiac (+)[3H]PN 200-110 binding sites induced by amlodipine also persisted after the tissues were washed by centrifugation and suspension, whereas that induced by nifedipine was reversible under these conditions. Thus, our results suggest that the gradual onset and long-lasting pharmacologic effect of amlodipine are due to its slow binding kinetics (association and dissociation) of cardiovascular receptor sites in addition to its slow pharmacokinetics.

Alpha 1-adrenoceptors in human prostate: characterization and binding characteristics of alpha 1-antagonists

The role of alpha 1-adrenoceptors in the mediation of autonomic functions, particularly in the control of the cardiovascular system, is widely known. It has been shown that alpha 1-adrenoceptors localized in human prostate mediate the contraction of prostatic smooth muscles which produces an increase in the intraurethral pressure and thus, these receptors are important in the regulation of bladder outlet resistance. Alpha 1-antagonists such as prazosin relieve the symptoms of bladder outlet obstruction in men with symptomatic benign prostatic hypertrophy (BPH) by blocking alpha 1-adrenoceptors, thereby decreasing prostatic tone and urethral resistance. Thus, alpha 1-adrenergic stimulation may be one of the most important factors in the development of urinary obstruction in BPH. Alpha 1-adrenoceptors in human prostate have been identified and characterized extensively by functional, radioligand binding and molecular biological techniques. These studies provide evidence in support of the concept that the alpha 1C-subtype forms the majority of alpha 1-adrenoceptors in human prostatic smooth muscles. It has been shown that YM617 (tamsulosin) and naftopidil have higher affinities to alpha 1-adrenoceptors in the prostate than in the aorta. Some alpha 1-antagonists, such as prazosin and terazosin, are not selective with respect to alpha 1-adrenoceptor subtypes, while others, such as 5-methylurapidil and indoramin, show higher potencies for alpha 1C-adrenoceptors and much lower potencies for alpha 1A- and alpha 1B-subtypes. In conclusion, the recent findings from pharmacological and molecular biological studies indicate that selective antagonists of alpha 1C-adrenoceptors could be effective in the treatment of urinary obstruction in symptomatic BPH with fewer cardiovascular side effects.

Expression and localization of a major lysosomal membrane sialoglycoprotein (LGP107) in plasma membranes of rat osteoblasts and osteocytes

The immunocytochemical localization of a major lysosomal membrane sialoglycoprotein with a molecular mass of 107 kDa, which was designated as LGP107, was investigated in osteoblast lineage cells involved in osteoclastic bone resorption using specific polyclonal antibody against LGP107. Osteoclastic bone resorption was induced by transplantation of parathyroid glands. In control experiments, no immunoreaction product for LGP107 was recognized in osteoblasts and osteocytes. Strong immunoreaction products for LGP107 occurred on the plasma membranes in the osteoblasts and osteocytes prior to the appearance of osteoclasts one day after transplantation of the parathyroid glands. Furthermore, two days after induction, strong diaminobenzidine reactions were also observed on the plasma membranes in the osteoblastic cells adjacent to the active osteoclasts. These data suggest that LGP107 in osteoblastic cells and osteocytes may play an important role in cell-recognition and/or cell-adhesion, and that LGP107 may be involved in osteoblastic degradation of the osteoid as well as exposure of the bone surface.

Role of 2,3,5-trichlorophenyl methyl sulfone, a metabolite of 1,2,4-trichlorobenzene, in the induction of hepatic microsomal drug-metabolizing enzymes by 1,2,4-trichlorobenzene in rats

2,3,5- and 2,4,5-trichlorophenyl methyl sulfides, 2,3,5- and 2,4,5-trichlorophenyl methyl sulfoxides, and 2,3,5- and 2,4,5-trichlorophenyl methyl sulfones (TCPSO2Mes) were detected in the urine of rats dosed with 1,2,4-trichlorobenzene (TCB). After the administration of 1,2,4-TCB to rats, swift decreases in concentrations of 1,2,4-TCB in blood, liver, kidneys, and adipose tissue were observed. On the other hand, 2,3,5-TCPSO2Me appeared in blood, liver, kidneys, and adipose tissue and remained detectable in the blood and the three tissues until 120 hr. The increases in the activities of aminopyrine N-demethylase and aniline hydroxylase and the contents of cytochromes P450 and b5 in hepatic microsomes produced by 1,2,4-TCB occurred after increases in the hepatic concentration of 2,3,5-TCSO2Me. 2,3,5- and 2,4,5-TCPSO2Me increased the above four parameters in rat liver microsomes. The inducing intensity of 2,3,5-TCPSO2Me was much higher than that of 2,4,5-TCPSO2Me. 2,3,5-TCPSO2Me was considered to be a potent inducer and to play a principal role in the induction by 1,2,4-TCB. When 1,2,4-TCB was injected ip into bile duct-cannulated rats, little 2,3,5-TCPSO2Me was detected in blood, liver, kidneys, and adipose tissue. In the antibiotic-pretreated rats dosed with 1,2,4-TCB, 2,3,5-TCPSO2Me concentrations in the blood and the three tissues markedly decreased. These findings suggest that the formation of methylsulfonyl metabolites from 1,2,4-TCB depends largely upon the metabolism of some precursor(s) excreted in the bile by intestinal microflora. The increasing effects of 1,2,4-TCB administration on the activities of aminopyrine- and aniline-metabolizing enzymes and the contents of cytochromes P450 and b5 in hepatic microsomes were not observed in the bile duct-cannulated rats. These findings provide evidence that the induction of drug-metabolizing enzymes by 1,2,4-TCB is not due to the action of 1,2,4-TCB itself but is due to its methylsulfonyl metabolite, 2,3,5-TCPSO2Me.

Correlation between the plasma concentration of mepirodipine and its occupancy of Ca2+ antagonist receptors in rats

The relationship between the plasma concentration of mepirodipine (1,4-dihydropyridine Ca2+ antagonist) and its occupancy of cardiac and cerebral Ca2+ antagonist receptors in rats has been characterized by a radioreceptor assay technique using (+)-[3H]PN 200-110. Oral administration of mepirodipine in rats produced a dose-dependent and sustained decrease in the number of specific (+)-[3H]PN 200-110 binding sites in both tissues, and the effect was more pronounced in the cardiac tissue than in the cerebral cortex. The occupancy of cardiac and cerebral Ca2+ antagonist receptors by mepirodipine correlated well with its plasma concentration, whereas a 20-fold higher plasma concentration of this drug was necessary to occupy Ca2+ antagonist receptors in the cerebral cortex. Thus, these data suggest that mepirodipine occupies Ca2+ antagonist receptors in cardiovascular tissue selectively over those in brain tissue.

Antioxidative effect of protoporphyrin and increase of glutathione in protoporphyrin-administered rat liver

The effect of protoporphyrin (PP) administration on the activities of enzymes related to and/or involved in lipid peroxidation and on the content of reduced glutathione (GSH) was investigated in rat liver. PP, at an intravenous dose of 20 mg/kg, increased GSH content, caused a weak suppression of NADPH-cytochrome c reductase activity and a slight increase of gamma-glutamyl transpeptidase activity 24 h after dosing, but had no effect on the activities of other enzymes such as xanthine oxidase, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase, gamma-glutamylcysteine synthetase or glutathione synthetase. Treatment of rats with diethyl maleate following PP injection resulted in the disappearance of antioxidative action of PP. Furthermore, sinusoidal, but not canalicular, efflux of hepatic GSH was decreased by the PP treatment. The increase of liver GSH content by PP treatment due to the decrease of sinusoidal efflux of GSH from the liver, thus would be involved in the exertion of antioxidative action of PP.

Increased synthesis and specific localization of a major lysosomal membrane sialoglycoprotein (LGP107) at the ruffled border membrane of active osteoclasts

The immunocytochemical localization was investigated of a major lysosomal membrane sialoglycoprotein with a molecular mass of 107 kDa, which was designated as LGP107. The study utilized rat osteoclasts with different bone resorbing activity and osteoclast precursors at various stages of differentiation and maturation together with monospecific antibodies to this protein. Despite its localization primarily in lysosomes and endosomes in the other cell types examined, LGP107 was exclusively confined to the apical plasma membrane at the ruffled border of the active osteoclast, where the osteoclast is in contact with the bone surface. The protein was also concentrated in a number of endocytic vacuoles in the vicinity of the ruffled border membrane. However the labeling was not found in the basolateral membranes of the active osteoclast. The ruffled border membrane detached from the bone surface showed a marked decrease in the extent of the immunolabeling. The post- and/or resting osteoclasts, which were located away from the bone surface, were totally devoid of the membraneous localization of LGP107. No definite immunolabeling was found in the immature preosteoclasts. These results indicate that the protein is largely synthesized in the active osteoclast and rapidly translocated to the ruffled border membrane by vectorial vesicle transport. LGP107 is suggested to contribute to the formation and maintenance of the specialized acidic environment for bone resorption.

Management of intractable pain with percutaneous epidural spinal cord stimulation: differences in pain-relieving effects among diseases and sites of pain

This study is a survey of the overall clinical results achieved with our pain treatment method, percutaneous epidural low-frequency (1.6-8.0 Hz) spinal cord stimulation. It examines the relationship between the effectiveness of epidural spinal cord stimulation (ESCS) and diseases or sites of pain. Continuous indwelling of the catheter electrodes in the posterior epidural space ranged from 3 to 67 days, and the duration of percutaneous ESCS varied from less than 1 wk to more than 1 yr. Complete pain relief (100%) was achieved during stimulation in 11.5% of the patients (52 of 454). Complete (100%) to partial (more than 30%) pain relief occurred in 71.1% of the patients. In six (1.3%) patients pain was aggravated by stimulation. Analgesics and/or sedatives were discontinued completely after treatment in 52 patients (11.5%) and reduced in 263 patients (57.9%). The number of patients who rated pain relief better than 50% was significantly more in carcinoma/sarcoma and causalgia (P < 0.001), and significantly less in postherpetic neuralgia and thromboangitis obliterans/arterial sclerosis obliterans (P < 0.001) than the average in all diseases. There was a significantly high responsiveness to ESCS in female patients in comparison to male patients (P < 0.05). Pain in the head/face, neck/upper extremities, and trunk responded more to ESCS than pain in the lower extremities. Alleviation of pain by ESCS was lower when the verbal pain score was high. There were no major complications in percutaneous ESCS. Thus, we have demonstrated that pain-alleviating effects of ESCS varies significantly by disease and site of pain, and that this simple percutaneous method can be used for a relatively long period.

Implantation treatment method of slow release anticancer doxorubicin containing hydroxyapatite (DOX-HAP) complex. A basic study of a new treatment for hepatic cancer

We performed an experimental study on slow releasing anticancer drug implantation treatment as a new therapy for hepatocellular carcinoma. Hydroxyapatite (HAP) was chosen for the carrier material and doxorubicin hydrochloride (DOX) for anticancer agent. DOX-HAP was produced by adsorbing DOX to porous HAP particles of 1375 +/- 125 microns diameter using the freeze drying method. In vitro experiments showed slow release of the drug resulting in the steady release of DOX from HAP for 1 month duration. In healthy white rabbits with DOX-HAP implantation in the liver, serum DOX was not detectable, and DOX release rate was stable at the implanted region after 7, 14, and 21 days. When DOX-HAP (DOX; 100 mg kg-1) was administered to mice with sarcoma 180, an improved survival rate was observed without acute toxicity. We also found that VX2 liver tumour growth on white rabbit was inhibited by implantation of DOX-HAP, without acute toxicity. We hope that DOX-HAP implantation therapy will open up new avenues for the treatment of hepatoma.

Delayed-type hypersensitivity responses regulate collagen deposition in the lung

A previous report showed that hamsters immunized by epicutaneous application of 2,4,6-trinitrochloro-1-benzene (TNCB) were susceptible to the development of pulmonary interstitial fibrosis (PIF) if challenged in the lung with the water-soluble form of this hapten 2,4,6-trinitrobenzene sulphonic acid (TNBS). In this study, we investigated the immunological mechanisms that contributed to increased collagen content in the lungs of hapten-immune hamsters after receiving a pulmonary challenge of the sensitizing hapten trinitrophenol (TNP). In order to evaluate the concept that delayed-type hypersensitivity (DTH) reaction modulated their response to TNP in the lung such that it eventuated into PIF, we compared the cutaneous DTH response (48 hr after challenge) with lung collagen deposition (14 days after challenge) in several lines (strains) of hamsters. The inbred LSH strain, was a high responder in the DTH assay to TNP and developed non-resolving PIF in the hapten-immune animals. This is called hapten-immune pulmonary interstitial fibrosis or HIPIF. We also observed that female LSH hamsters were more susceptible to HIPIF induced by TNP than males. On the other hand, age factors influenced DTH and PIF in random-bred LVG hamsters since young hamsters (3 months old) were low responders to TNP and did not develop PIF in the HIPIF model but matured LVG hamsters (retired breeders) possessed DTH reactivity to TNP and subsequently developed PIF. These results suggest that lung collagen deposition in hapten-immune hamster is regulated by T-lymphocyte-mediated immune inflammation (DTH) in the lung and both are dependent on the ability to develop a cutaneous DTH reaction to the hapten. The elucidation of possible mechanisms of DTH-mediated non-granulomatous, non-resolving PIF is important for understanding of the role of environmental chemicals similar in action to haptens in the mediation of skin and lung diseases.

Immunological tolerance to hapten prevents subsequent induction of hapten-immune pulmonary interstitial fibrosis (HIPIF)

Pulmonary interstitial fibrosis (PIF) is a morphological term which in part can be defined as accumulation of collagen in the extracellular matrix. Previously we showed that hamsters sensitized with 2,4,6-trinitro-1-chlorobenzene (TNCB) developed PIF 14 days after an intratracheal challenge with 2,4,6-trinitrobenzene sulfonic acid (TNBS). The participation of delayed-type hypersensitivity (DTH) in lung collagen deposition was clearly demonstrated. In this paper, we use an adaptation of this model to mice and show that the lung collagen deposition observed was related to the genetic ability of the strain to maintain a DTH response to the immunizing hapten (TNP). Specifically, the lung collagen deposition on Day 14 in hapten-sensitized, challenged animals in high responder to TNP (BALB/c, H-2d) was higher than that in low responder mouse (C57BL/6, H-2b). Furthermore, aged C57BL/6 strain (retired breeders) possessed a DTH response to TNP and produced significantly higher accumulation of hydroxyproline than that of TNBS-challenged-only animals. A DTH mechanism for the induction of the fibrosis is consistent with the observation that responder mice that were made tolerant to the antigen were unable to respond to the lung challenge with a specific increase in lung index or collagen deposition. These results suggest that effector T lymphocytes that are important in DTH play a key role in the regulation of lung collagen deposition in hapten-immune pulmonary interstitial fibrosis (HIPIF) in mice.

Protoporphyrin overload in unrestrained rats: biochemical and histopathologic characterization of a new model of protoporphyric hepatopathy

We determined the feasibility of producing protoporphyric hepatopathy in unrestrained rats by infusing protoporphyrin into their portal circulation via chronic indwelling catheters. Sprague-Dawley rats, 200-300 g, received single (8.5-27.8 mumol) or multiple (64.1-208.7 mumol) infusions of protoporphyrin over 3-240 h. Single protoporphyrin infusions increased the hepatic protoporphyrin concentration from < 1 nmol/g up to 1368 nmol/g; multiple infusions up to 3908 nmol/g. The maximal non-hepatic tissue concentrations averaged 243 nmol/g in the spleen. Hepatocanalicular and ductular birefringent pigmented deposits were found in all livers, generally proportional to the protoporphyrin load. Aggregates of crystalline protoporphyrin were detected in biliary ductules, canaliculi, hepatocytes, Kupffer cells and fat-storage cells by electron microscopy. Laboratory abnormalities included elevations of the transaminases, LDH, GGTP and bilirubin and a modest fall in the haematocrit suggesting a mixture of red blood cell and hepatic injury. Thus, protoporphyric hepatopathy was produced by infusions of protoporphyrin into the portal circulation. This model may aid in understanding the pathogenesis and pathophysiology of liver disease in protoporphyria.

Proliferating cell nuclear antigen (PCNA) immunostaining as an alternative to bromodeoxyuridine (BrdU) immunostaining for brain tumours in paraffin embedded sections

Immunohistochemical staining for proliferating cell nuclear antigen (PCNA) and BrdU using anti-PCNA and anti-BrdU monoclonal antibodies, respectively, was performed in 16 human brain tumours, including 3 glioblastomas multiforme, 2 anaplastic astrocytomas, 1 cerebellar astrocytoma, 2 recurrent meningiomas, 4 non-recurrent meningiomas, 3 neurinomas and 1 medulloblastoma. Patients with brain tumours received an injection of bromodeoxyuridine (BrdU) intravenously during surgery, and tumour specimens were fixed in 70% ethanol and embedded in paraffin. The percentage of positive cells for PCNA was compared with a BrdU labelling index using adjacent paraffin-embedded sections. The percentage of PCNA-positive cells was correlated with the BrdU labelling index and the histological malignancy of the brain tumours. The correlation coefficient was 0.84. This suggests that the immunohistochemical staining for PCNA in paraffin sections is a good alternative to the BrdU labelling index.

A sustained occupancy in vivo of cardiovascular calcium antagonist receptors by mepirodipine and its relation to pharmacodynamic effect in spontaneously hypertensive rats

The occupancy in vivo of cardiovascular and cortical Ca++ antagonist receptors by mepirodipine in spontaneously hypertensive rats (SHR) was investigated. At 0.5, 3 and 6 hr after an oral administration of mepirodipine (3 mg/kg) in SHR, there was a significant (69, 51 and 41%, respectively) decrease in the number of cardiac (+)-[3H]PN 200-110 binding sites (Bmax) compared to control values. At 12 hr later, the Bmax value returned to the control value. On the other hand, the mepirodipine administration had little effect on the dissociation constant (Kd) for cardiac (+)-[3H]PN 200-110 binding except at 0.5 hr, when there was a significant increase in the value, suggesting a change in the density rather than affinity of Ca++ antagonist receptors. In the cerebral cortex of these rats, there was a significant (34%) decrease in Bmax values for (+)-[3H]PN 200-110 binding only at 0.5 hr after mepirodipine administration. In contrast, nifedipine administration had a significant increase in Kd values for cardiac (+)-[3H]PN 200-110 binding without a change in Bmax values. The occupancy of cardiac Ca++ antagonist receptors by mepirodipine correlated significantly with its hypotensive effect in SHR. There was approximately a 39 mm Hg reduction of blood pressure by occupying 50% of these receptors. After an i.v. injection of (+)-[3H]PN 200-110 (15 microCi) to SHR, there was specific binding of the ligand in particulate fractions of heart, aorta, ileum and cerebral cortex, but not liver and kidney.(ABSTRACT TRUNCATED AT 250 WORDS)

[Fundamental study on hyperthermic chemotherapy using adriamycin-loaded hydroxyapatite]

We developed a porous hydroxyapatite ceramic (HAP) incorporating adriamycin (ADM), that is, ADM-HAP as a new delivery system (DDS) to release ADM gradually. We also researched the possibility of hyperthermic chemotherapy using ADM-HAP by in vitro and in vivo experiments. As for in vitro experiments, we implanted HAPs into uniform Agar-Phantom, and observed thermal distribution generated by Thermotron-RF 8 using thermography. Then we found the hot spot that the edge temperature of HAPs always at the range of 0.5-0.7 degrees C than in the other regions. On the other hand, slow constant release (1%) of ADM from ADM-HAP in PBS was recognized for 24 hrs up to 30 days. When the incubating temperature was shifted up to 42.5 degrees C or 44 degrees C from 37 degrees C, the quantity released over 24 hrs increased about 1.1-fold or 1.3-1.4-fold of the cases at 37 degrees C, respectively. In the in vivo experiment, we inoculated Sarcoma 180 cells in the leg of ddY-mice, and measured the tumor growing times by the treatment of hyperthermia+ADM (whole body), hyperthermia+ADM (tumor region) or hyperthermia+ADM-HAP (tumor region). Then we found that the effect of hyperthermia with ADM-HAP inhibited synergistically the tumor growth as compared with hyperthermia with ADM. Consequently, we succeeded in tumor growth inhibition by increasing the temperature and by limiting ADM release to only a target region using hyperthermia with ADM-HAP.

Analysis of tumor necrosis factor and lymphotoxin secreted by incubation of lymphokine-activated killer cells with tumor cells

This study investigated the secretion of a tumor necrosis factor (TNF) and lymphotoxin (LT) from lymphokine-activated killer (LAK) cells during co-culture with glioblastoma cell lines, autologous glioma cells, and other non-gliomatous tumor cell lines (K562 and Daudi). Cytokine secretion from peripheral blood mononuclear cells (PBMC) was also examined. The TNF activity of culture supernatants was measured by L cell cytotoxic assay, and a neutralization test using anti-TNF and/or anti-LT antibodies determined whether the cytotoxic activity was due to TNF or LT. The results show that LAK cells secrete both TNF and LT during monoculture and release increased amounts of TNF and LT with non-gliomatous tumor cell stimulation, but PBMC secrete only TNF with tumor cell stimulation. Glioblastoma or anaplastic astrocytoma cells, however, did not stimulate cytokine secretion from either LAK cells or PBMC. This indicates a discrepancy between the capability of LAK cells to lyse malignant glioma cells and cytokine secretion from LAK cells, and suggests that malignant glioma cells may produce some factors which inhibit cytokine secretion from LAK cells.