Clinical manifestations of HBsAg and anti-HCV negative chronic liver disease in Nagasaki Prefecture, Japan

The discovery of hepatitis C virus (HCV) has enabled the diagnosis of type C chronic liver disease, which had in the past been diagnosed as part of non-A, non-B chronic liver disease. Although most cases with chronic liver disease are caused by hepatitis B virus (HBV) or HCV infection, there are still cases of non-B, non-C chronic liver disease. Forty patients with chronic liver disease, who were seronegative for hepatitis B surface antigen and antibody to HCV, were followed for a mean period of 72 months. The clinical manifestations in these patients were compared with those reported for type B and type C chronic liver disease. Of the 40 patients, 22 were diagnosed with chronic hepatitis, 14 with liver cirrhosis and 4 with hepatocellular carcinoma (HCC). Twenty-seven (67.5%) patients showed mild alanine aminotransferase activity profiles, and the natural clinical course of most patients showed a slow progression compared with that reported for type B and type C patients. The yearly incidence of HCC was 9.7% in patients with liver cirrhosis and 3.9% in chronic hepatitis. These rates were similar to those in type B or type C patients. This suggests that our population sample contained a number of patients with type B, type C or other etiologic agent(s), because 66.7% of the patients who developed HCC had some evidence of exposure to HBV or HCV. Our results suggest that more detailed and accurate tests for detecting HBV and HCV should be considered before making the diagnosis of non-B, non-C chronic liver disease, and that there is the need to reveal unknown etiologic agent(s).

The endothelin receptor is a major determinant for the nonlinear tissue distribution of the endothelin antagonist BQ-123

The nonlinearity in the pharmacokinetics of the cyclopentapeptide endothelin antagonist BQ-123 was studied. Both the total body clearance and tissue-to-plasma concentration ratio (Kp) were investigated in rats under a wide range of steady-state plasma concentrations (Cpss) obtained by changing the intravenous infusion rate of BQ-123. The total body clearance was constant up to a Cpss level of 50 microM, although it was markedly decreased at higher Cpss values, which suggests the existence of a saturable elimination mechanism. A Cpss-dependent nonlinearity in the apparent Kp values (Kp,app) was clearly observed in many organs including lung, heart, spleen, pancreas, adrenal, stomach, intestine, colon, aorta, testis and muscle, where the endothelin ET(A) receptor is known to be localized. By fitting the saturation curves of the Kp,app values, a similar dissociation constant (Kd) was obtained for most organs at 5 to 10 nM, which is close to the reported Kd values of BQ-123 for the endothelin ET(A) receptor. The saturable portion of the Kp,app values observed in vivo showed a good correlation with reported values of the endothelin ET(A) receptor density. Binding of BQ-123 to isolated membrane fractions from several organs demonstrated clear saturability for the lung, heart, spleen and liver with Kd values of 1 to 3 nM. Such specific binding also showed a good correlation with the saturable portion of the Kp,app values. From these results, we concluded that the endothelin receptor(s) is responsible for the nonlinear tissue distribution of BQ-123 in rats.

Effects of X irradiation on metabolism of proteoglycans

The effects of X irradiation on matrix formation by growth-plate and articular chondrocytes, as reflected by metabolism of proteoglycans and type II collagen, were examined in a rabbit chondrocyte culture system. Irradiation with 1 to 10 Gy selectively inhibited synthesis of proteoglycans (incorporation of [35S]sulfate) depending on the stage of differentiation of the irradiated cells; however, synthesis of type II collagen was not affected. Irradiation of an immature culture, in which chondrocytes had just reached confluence, suppressed incorporation of [35S]sulfate into the glycosaminoglycan, 10 Gy inducing approximately 45-50% inhibition. In contrast, the irradiation of mature cultures, in which chondrocytes had already secreted extensive cartilage matrix, did not affect the rate of synthesis of proteoglycans (incorporation of [35S]sulfate). We also found that here irradiation stimulated the degradation of proteoglycans, but with the effect differing in growth-plate chondrocytes and articular chondrocytes. In growth-plate chondrocytes, cleavage from a site close to the G1 globular domain induced by 10 Gy enhanced the release of 35S-labeled proteoglycans into the medium, whereas in articular chondrocytes, irradiation had only marginal effects on the release of 35S-labeled proteoglycans. Our results show that irradiation with 1-10 Gy impaired proteoglycan metabolism in cartilage, with differing effects according to the stage of cell differentiation and the type of chondrocyte.

[Laser prostatectomy--image analysis by transurethral ultrasonography]

BACKGROUND

Conventional transurethral Nd:YAG laser ablation of the prostate does not significantly reduce the volume of prostate and patients frequently experience post-operative urinary retention. Thus in the present study, prostatic tissue was extensively vaporized with laser fiber to produce a definite cavity during the operation.

METHODS

Between August 1993 and April 1995, laser prostatectomy utilizing Ultraline was carried out on 91 patients with BPH, 38 of these patients had histories of urinary retention. The size and form of the prostate were examined by transurethral ultrasonography (TUUS) prior to surgery and ablation was conducted based on the findings. The results were checked by TUUS a second time.

RESULTS

Operating time was 84.1 minutes on the average including the time for systematic needle biopsy and cystostomy for irrigation. Total irradiation dose was 132,035J on the average. The catheter was removed at an average 5.8 days postoperatively. I-PSS was noted to improve from 15.3 to 5.6, maximum flow rate, 9.3 to 15.8 ml/s, average flow rate, 4.6 to 9.2 ml/s and residual urine, 76.0 to 15.9 ml. The volume of the prostate was reduced by 31.5% (39.3 to 26.6 ml) and the patients could urinate for more than a year without discomfort. No serious complications were encountered though epididymitis was noted in 5 and urethral stricture in 10 patients.

CONCLUSION

The present laser prostatectomy is less invasive than TUR-P and the results might be equal to it.

Magnetic resonance arthrography in the assessment of anterior instability of the shoulder: comparison with double-contrast computed tomography arthrography

Forty-seven shoulders with traumatic anterior instability were studied by magnetic resonance arthrography (MRA) and computed tomography arthrography (CTA) to compare the diagnostic performance of these examinations in the evaluation of Bankart lesions. All shoulders were examined by arthroscopy to verify the lesions. Labral damage evaluated by MRA and by CTA correlated significantly with arthroscopic findings (MRA, r = 0.55, p < 0.0001; CTA, r = 0.45, p = 0.0050). MRA possessed higher sensitivity in detecting torn labra (MRA, sensitivity = 87%, specificity = 75%; CTA, sensitivity = 33%, specificity = 88%). In detecting displaced labra, sensitivity and specificity were 65% and 94% for MRA and 75% and 69% for CTA. The inferior glenohumeral ligament was depicted as a lax structure in 74% by MRA but in only 21% by CTA. We conclude that MRA is superior to CTA in detecting lesions associated with shoulder instability.

Nickellike soft-x-ray lasing at the wavelengths between 14 and 7.9 nm

We report what we believe is the first observation of clear soft-x-ray lasing in Ni-like Ag, Te, La, Ce, and Pr and also in Nd covering the spectral range 14.3-7.9 nm. A curved slab target was irradiated with quadruple 1.053-microm laser pulses. The pulse-to-pulse separation for the first three pulses was 400 ps, and that between the third and the fourth pulses was 1.6 ns. The pulse duration and irradiance on the target were 100 ps and ~7 x 10(13) W/cm(2), respectively. For all the targets the most intense lasing was observed at the fourth pump pulse.

Inhibition of cell-cell communication by commercial chlorinated paraffins in rat liver epithelial IAR 20 cells

The effects of six commercial chlorinated paraffins of different carbon chains length and chlorine content (Cereclor 50LV [C50LV], Hüls 60 [H60], Cereclor S45 [CS45], Cereclor S52 [CS52], Cereclor 42 [C42] and Cereclor 48 [C48] on cell communication have been investigated in the scrape-loading/dye-transfer assay in IAR 20 rat liver epithelial cells, as well as the effects of these compounds on connexin 43 (cx 43), the main gap junction protein in this cell line. The results clearly demonstrated that at non-cytotoxic concentrations C50LV, H60, CS45 and CS52 completely inhibited the cell communication within 1 hr. The short carbon chain length chlorinated paraffins (C50LV and H60) were inhibiting the cell communication at lower concentration than the intermediate carbon chain length chlorinated paraffins (CS45 and CS52). Almost complete inhibition of the cell communication was maintained for at least 24 hrs of H60 exposure. Immunoblots of IAR 20 cell extracts after H60-exposure showed a decreased phosphorylation of cx 43 after 1, 4 and 24 hrs of treatment. The phosphorylation pattern of cx 43 prepared from H60- or CS52-exposed cells was different from that prepared from 12-O-tetradecanoylphobol-13-acetate (TPA)-exposed cells after 1 hr treatment. The results show that the short and intermediate, but not the long carbon chain length chlorinated paraffins, are potent inhibitors of gap junction intercellular communication. Thus, our findings suggest that these compounds may act as tumour promoters.

Developmental changes in action potential and membrane currents in fetal, neonatal and adult guinea-pig ventricular myocytes

Developmental changes in electrophysiological properties were investigated in enzymatically isolated ventricular cardiomyocytes from fetal (45-55 days after conception), neonatal (1-5 days after birth) and adult (45-60 days after birth) guinea-pigs. Action potentials were elicited at 1 Hz in current-clamp mode, and membrane currents were measured using whole cell voltage clamp method. Action potential durations at 50% and 90% repolarization decreased between fetal and neonatal periods and increased between neonatal and adult periods, while there was no substantial age-related change in resting membrane potential and action potential overshoot. Because cell membrane capacitance increased with age, indicating a developmental increase in cell size, current density was normalized to membrane capacitance for each cell. The L-type calcium current (lCaL) density at 0 and + 10 mV was significantly smaller in fetal and neonatal cells than in adult ones, although the voltage dependence and inactivation kinetics were similar among the three age groups. The delayed rectifier K+ current (lK) density at 0 and + 30 mV was significantly smaller in fetal cells than in neonatal and adult ones. No significant difference in the inward rectifier K+ current (lK1) density was observed among the three age groups. Thus, the electrophysiological properties of the guinea-pig ventricular myocytes were demonstrated to change during pre- and postnatal development. The observed changes in action potential duration could be explained by changes in the balance between lK and lCaL.

Establishment of an in vitro cell derived from human angiosarcoma

We have succeeded in the establishment of a human endothelial cell line derived from a human angiosarcoma. These cells grew as monolayers with a "cobble stone" morphology. The cells produced endothelin and showed Weibel-Palade bodies in their cytoplasm. These findings show that the cells have specific differenciated functions, and might be useful for both fundamental endothelial cell biology and biological investigation of angiosarcoma.

A 19-kb CpG island associated with single-minded gene 2 in Down syndrome chromosomal region

To help in isolating the genes involved in Down syndrome, we sought CpG islands in 4 Mb cosmid/PAC contigs spanning most of the 21q.22.2 band using seven rare cutting enzymes. A striking feature was observed upstream of hSIM2 where at least 41 rare-cutting sites were clustered within a 20-kb region. To investigate the structure of the cluster, a cosmid containing hSIM2 was submitted to shotgun sequencing. Sequence analysis revealed that the cluster was a long CpG island extending 19, 128 nucleotides which includes in the first and second exons of hSIM2. Taken together with our observation in which the CpG islands were concentrated within 1.2 Mb around hSIM2, we propose that this region functions as an R-band, and the cluster provides a unique element for marking of DNA for the spatial and temporal expression of the hSIM2 locus.

Two amine oxidases from Aspergillus niger AKU 3302 contain topa quinone as the cofactor: unusual cofactor link to the glutamyl residue occurs only at one of the enzymes

Amine oxidases (EC 1.4.3.6) from Aspergillus niger, AO-I (2 x 75 kDa) and AO-II (80 kDa), were examined to determine the cofactor structure. Inactivated with p-nitrophenylhydrazine, they showed absorption and fluorescence spectra similar to those published for other copper amine oxidases and to topa hydantoin p-nitrophenylhydrazone. After digestion by thermolysin and pronase, cofactor peptides were purified by HPLC and sequenced. For thermolytic peptides, a typical topa consensus sequence, Asn-X-Glu-Tyr, was obtained for AO-II, although in case of AO-I it overlapped with Val-Val-Ile-Glu-Pro-Tyr-Gly. For pronase peptides of AO-I, only the latter sequence was obtained. NMR and mass spectroscopy confirmed the residue X as topa p-nitrophenylhydrazone in AO-II and revealed the presence of a residue Z attached to the Glu in the peptide Val-Val-Ile-Glu(Z)-Pro of AO-I. This residue was separated from the peptide by hydrolysis and identified as a product derived from topa quinone. The data, together with amino-acid sequence of AO-I, confer strong evidence for topa quinone as the cofactor, bound in the typical consensus sequence. Raman spectra of the p-nitrophenylhydrazone derivative of AO-I and its pronase peptide showed essentially the same peaks matching to a model compound for topa p-nitrophenylhydrazone. However, there may exist an unusual ester link between the topa-404 and Glu-145 in the native enzyme.

[Correlation between expression of RB protein and prognosis of gastric cancer]

In this study, the expression of retinoblastoma (RB) protein was investigated immunohistochemically in 94 patients with gastric cancer. Overexpression of RB was detected in 48 tumors (51.1%). There was no significant association among the expression of RB, histologic type, lymph node metastasis, and liver metastasis. However, a significant difference was noted with respect to depth of invasion and peritoneal metastases. Among 94 patients, peritoneal metastases were observed in 11 patients. RB expression was detected in only two of these cases with peritoneal metastases, which was significantly less than those without peritoneal metastases. In relation to prognosis, patients with RB-positive tumors had a significantly better prognosis than those with RB-negative tumors. In conclusion, this study suggested that expression of RB has a prognostic value in gastric cancer.

Allele detection and population study in Japanese using two STR loci (CYP19 and HUMTH01)

Allele fragments at two polymorphic short tandem repeat (STR) loci, CYP19 and HUMTH01, were simultaneously amplified in a sample of 200 unrelated Japanese individuals living in the Kanto area, including Tokyo. After electrophoresis in PAG, the new alleles 7, 10, 11, 12, and 13 were detected at the CYP19 locus in Japanese. HUMTH01 allele frequencies in Japanese differed greatly from those reported for Caucasians and Asians living in the US. The polymorphism information content (PIC) in Japanese was calculated as 0.46 for CYP19 and 0.66 for HUMTH01. The power of discrimination (PD) was 0.7 for CYP19 and 0.86 for HUMTH01, and the combined PD was calculated as 0.96. No significant deviations from Hardy-Weinberg equilibrium could be observed for these systems.

[Long-term effect of transcatheter arterial embolization therapy for renal angiomyolipoma]

We report a case of a 21-year-old man with a right renal angiomyolipoma who has been observed for 20 months after successful treatment with selective transcatheter arterial embolization (TAE). In May 1993, he was transferred to our hospital for the treatment of an abdominal mass. Examination revealed a solid and fat-containing right renal tumor on computed tomography (CT) and magnetic resonance imaging (MRI), hypervascular staining with multiple peripheral microaneurysms on renal angiogram, indicating an angiomyolipoma (AML). He did not have any signs of tuberous sclerosis. Because he complained of abdominal pain and the tumor was 9 cm in diameter, TAE of the tumor using polyvinyl alcohol foam was performed to prevent life-threatening hemorrhage. Renal angiogram after TAE demonstrated a complete shut-down of blood supply to the tumor and CT scan, 6 and 20 months after TAE, demonstrated a decrease in size to 4.5 cm in diameter, showing a favorable long-term effect of treatment. He has been symptom-free for 20 months. TAE appears to be a safe and effective treatment for AML, preventing tumor growth and thus possibly hemorrhage or rupture of the tumor over the long -term.

Inhibition of oxidation of low density lipoprotein by troglitazone

The effect of a new oral hypoglycemic agent troglitazone, (+/-)-5-[4-(6-hydroxy-2,5,7,8-tetramethylchroman-2-yl-methoxy)benz yl]-2,4-thiazolidinedione as an antioxidant against the free radical-mediated oxidation of low density lipoprotein (LDL) was studied. The oxidation of LDL gives cholesteryl ester hydroperoxide and phosphatidylcholine hydroperoxide as major primary products. Troglitazone incorporated exogenously into LDL inhibited the oxidations of LDL induced by either aqueous or lipophilic peroxyl radicals and suppressed the formation of lipid hydroperoxides efficiently. Ascorbic acid added into the aqueous phase spared both endogenous alpha-tocopherol and troglitazone in LDL. It was also found by absorption spectroscopic and electron spin resonance (ESR) studies that troglitazone reacted rapidly with a galvinoxyl radical to give a chromanoxyl radical which gives the same ESR spectrum as alpha-tocopherol. This ESR spectrum disappeared rapidly when ascorbic acid was added into the system. These results show that troglitazone acts as a potent antioxidant and protects LDL from oxidative modification.

New jet irrigation bipolar system

Irrigation bipolar systems are particularly useful for the washout of hematomas in subarachnoid hemorrhage during the acute stage of surgery and for preventing adherence of tissue to the bipolar tips during coagulation. These systems have become essential tools, and numerous improvements have been made to them. First, regarding the flow volume, both the interval of droplets and the size of individual water droplets can be adjusted. Second, this system is equipped with two major functions. The first is a preirrigation function, in which a small amount of irrigation water flows before operation of the bipolar coagulation. This wets the bipolar tips, eliminating any heat remaining from the previous use. Another function is postirrigation; after the coagulation has stopped, continuous irrigation is quickly provided to achieve a standby state by cooling down the tissue and the tips of the bipolar forceps. By using both of these functions, mild coagulation without adherence of burned tissue and clots to the bipolar forceps and minimization of residual heat during frequent use can be achieved. This article describes the new jet irrigation bipolar system and the use of an actual system that combines jet irrigation functions with the new cooling functions.

Clinical significance of serum CYFRA 21-1 in gastric cancer

We studied the clinical significance of the soluble cytokeratin 19 fragment detected with monoclonal antibody CYFRA 21-1 in the sera of patients with histologically proven gastric cancer. Sera of 110 patients with gastric cancer were analysed for CYFRA 21-1 levels by a two-step sandwich enzyme immunoassay. There were no significant differences between CYFRA 21-1 levels and the histotype, depth of invasion or vessel invasion. However, CYFRA 21-1 was significantly higher in the presence of peritoneal metastases, liver metastases and extensive nodal involvement. When the positive cut-off value was defined as 5 ng ml-1, the CYFRA 21-1 in the stage IV and recurrent cases was 55.6% and 66.7%, respectively, which was as high as carcinoembryonic antigen (CEA) and greater than carbohydrate antigen 19-9 (CA 19-9). The positivities in stage I/II and III were zero and 5.9%, respectively, and false-positive rate in 76 patients with benign gastrointestinal disorders was 2.6%. There appeared to be no correlation between CYFRA 21-1 and CEA or CA 19-9. The patients with above 5 n ml-1 of CYFRA 21-1 had a significantly poorer prognosis. Multivariate analysis indicated that CYFRA 21-1 was an independent prognostic factor, while CEA and CA 19-9 failed to be of prognostic value. In conclusion, CYFRA 21-1 is a reliable tumour marker for gastic cancer in predicting very advanced cases, recurrence of the disease and overall poor prognosis.

Leuchtenberger bodies in flat adenomas of the colorectal mucosa: a comparison between Japanese and Swedish patients

The dysplastic epithelium of flat colorectal adenomas was found to contain DNA inclusion granules, known as Leuchtenberger bodies (LB). Hematoxylin and eosin-stained sections of 263 colorectal flat neoplastic lesions (i.e., flat adenomas, and flat adenocarcinomas) collected in Japan and Sweden were scrutinized for the presence of such intraepithelial inclusions. LB were recorded in 87.1% of the 263 flat colorectal neoplastic lesions. The frequency of flat colorectal lesions having LB was similar in Japan (160 of 178 or 89.8%) to that in Sweden (69 of 85 flat lesions or 81.2%), suggesting that the occurrence of LB may not be influenced by race or environment. Direct immunoperoxidase detection of nuclear DNA fragmentation and transmission electron microscopy studies indicated that the inclusions contained apoptotic material. The semiquantitative assessment of histochemically labeled apoptotic granules indicated that the number of lesions having moderate to large numbers of apoptotic granules (++/ ) was higher in flat adenomas with high-grade dysplasia, suggesting that the occurrence of these granules may be related to the degree of severity of the dysplastic process. A better knowledge of LB may improve our understanding of the possible relationship between apoptosis, host immune response and carcinogenesis in flat colorectal adenomas.

[Cytomegalovirus fetal infection. Porencephaly with polymicrogyria in a 15-year-old boy]

A boy, born after 41 weeks of gestation, presented with splenomegaly, microcephaly and chorioretinitis accompanied by immaturity signs. His mother was in good health but her previous pregnancy had been aborted owing to rubella. Laboratory data, including serological and virological evidence, confirmed the diagnosis of fetal cytomegalovirus infection. CT scan indicated a large cyst in the left temporal lobe and periventricular calcifications. At about 8 months of age, convulsions were noticed which were not controlled effectively by medication. There was spastic rigidity without significant psychomotor development. He died at the age of 15. Postmortem neuropathological examination revealed polymicrogyria predominant in the right cerebral hemisphere as well as a large cavity in the left temporal lobe communicating with the lateral ventricle. Widespread heterotopias and calcifications were observed notably in the periventricular white matter. No typical inclusion was found. By the method of Holzer and GFAP immunocytochemistry, no gliosis was noted in the cerebral cortex having the feature of polymicrogyria. This might support the theory that polymicrogyria is caused by neuronal migration failure.

Molecular cloning of c-jun and c-fos cDNAs from porcine anterior pituitary and their involvement in gonadotropin-releasing hormone stimulation

The presence of the typical transcription factors c-Jun, c-Fos and cAMP-responsive element (CRE)-binding protein in the porcine anterior pituitary was examined by molecular cloning and their involvement in the membrane signal cascade, especially their roles in gonadotropin-releasing hormone (GnRH) stimulation, were studied. Several cDNA clones were isolated from a porcine anterior pituitary cDNA library using cDNA probes. They were identified as porcine c-jun and c-fos by determining their nucleotide sequences, but a homologue for CREB341 which is a member of CRE-binding protein was not detected in porcine anterior pituitary. Reverse transcription-polymerase chain reaction (RT-PCR) analysis was performed to estimate the c-jun and c-fos mRNA contents in GnRH-, forskolin- (cAMP activator) and tetradecanoyl phorbol acetate- (TPA; protein kinase C activator) treated primary cultures of porcine anterior pituitary cells. Densitometric quantification demonstrated that GnRH and TPA treatment increased c-jun and c-fos mRNA levels significantly, whereas forskolin reduced the levels of both. Therefore, c-Jun and c-Fos are definitely present in porcine anterior pituitary and their mRNAs differentially involved in the signal transduction pathway mediated by two kinases. In particular, GnRH might regulate gonadotropin expression by increasing of c-jun and c-fos levels.

A novel anti-Thy-1 (CD90) monoclonal antibody induces apoptosis in mouse malignant T-lymphoma cells in spite of inducing bcl-2 expression

Mouse malignant T-lymphoma CS-21 cells can survive and proliferate in vitro when co-cultured with CA-12 stromal cells isolated from lymph nodes, but CS-21 cells undergo apoptotic cell death with DNA fragmentation when cultured alone. We immunized rats with CS-21 cells and raised monoclonal antibodies (MAbs) that recognized Thy-1 (CD90) or CD45 protein. The majority of these MAbs were able to inhibit the adhesion and apoptosis of CS-21 cells. When anti-Thy-1 MAbs were examined for their recognition site on Thy-1 glycoprotein, one of them, MCS-34, was found to recognize both Thy-1.1 and Thy-1.2. In addition, MCS-34, just like the anti-Thy-1 MAb G7, recognized the Thy-1A epitope. G7 was known to induce apoptosis in some T-cell hybridomas and in thymocytes. In CS-21 cells, however, G7 could not induce apoptosis, but MCS-34 could. Interestingly, MCS-34 enhanced the expression of bcl-2 protein, in spite of its ability to induce apoptosis. Upon examining the apoptosis-inducing mechanisms of MCS-34, we found that it promoted a sustained increase in cytoplasmic-free calcium in CS-21 cells. Calcium ionophore A23187 was also found to induce apoptosis in a dose-dependent manner. These results indicate that a sustained increase in cytoplasmic-free calcium by MCS-34 induces apoptosis in CS-21 cells in spite of bcl-2 protein expression.

Amino acids in highly conserved regions near the C-terminus of rat prolactin (PRL) play critical roles similar to those in binding of human GH to the PRL receptor

The fourth helix (helix 4) in the human growth hormone (hGH) molecule plays a role in binding to the GH receptor as well as the PRL receptor through topologically different amino acids. This study investigated the function of amino acids in the predicted helix 4 of rat prolactin (rPRL) using site-directed mutagenesis. Twenty mutants for 7 amino acid residues were expressed in COS-1 cells and their receptor binding and Nb2 proliferation activities were assayed. It was found that R174 (R at residue number 174), K179, and D181 are indispensable for PRL function, while D176, S177 and C189 are important to some extent. When these results were compared with those reported for binding of hGH to its receptors, the binding of PRL to the PRL receptor was shown to involve amino acids topologically similar to those in the binding of hGH to the PRL receptor, rather than those in the binding of hGH to the GH receptor.

Antianginal effects of FR144420, a novel slow nitric oxide-releasing agent

The aim of this study was to compare the antianginal effects of two compounds that release nitric oxide (NO) spontaneously, i.e. (+/-)-N-[(E)-4-ethyl-3-[(Z-hydroxyimino]-5-nitro-3-hexenyl] -3-pyridinecarboxamide (FR144420) and (+/-)-(E)-ethyl-2-[(E)-hydroxyimino] -5-nitro-3-hexenamide (FK409), in two different rat models of coronary vasospasm. In the rat methacholine-induced coronary vasospasm model, FR144420 suppressed the elevation of the ST segment dose dependently and significantly at 1.0 mg/kg, i.d. 185 min after its administration. FK409 suppressed the ST elevation only 5 min after its administration at 1.0 mg/kg, i.d. FR144420 and FK409 significantly decreased mean blood pressure at all doses tested only 5 min after their intraduodenal administration, but did not change heart rate at any time. Although the suppression of the ST elevation by FK409 had the same duration as its hypotensive effect, the FR144420-induced suppression of the ST elevation lasted longer than its hypotensive effect. In the rat vasopressin-induced coronary vasospasm model, FR144420 (32 mg/kg) significantly inhibited the depression of the ST segment both 60 min and 120 min after oral administration, whereas FK409 (32 mg/kg) significantly inhibited this ST depression only 60 min after oral administration. These data suggest that FR144420 inhibits coronary vasospasm for longer than FK409 does and particularly shows more prolonged antianginal effects than hypotensive effects in the methacholine-induced coronary vasospasm model. Thus FR144420 is expected to be a useful NO releaser for investigating the in vivo actions of NO.