[Histological observation of anterior capsular edges produced by continuous curvilinear and diathermy capsulorhexis]

Radiofrequency endodiathermy capsulorhexis (DC) is a new method for anterior capsulorhexis in cataract surgery. DC may confer some advantages over continuous curvilinear capsulorhexis(CCC) in certain clinical situations. The elasticity of capsulorhexis produced by DC and the proper diathermy time are still unclear. Histological examination of rabbit lenses, on which a variety of coagulation times (0.5 to 5.0 sec) were tested revealed that 0.5 sec was long enough to coagulate the anterior capsule and that the longer coagulation extend the tissue damage into the deeper cortex. Small capsulorhexis (3.5 mm in diameter) produced experimentally with DC showed less elasticity than that produced with CCC when the edge of the capsulorhexis was pulled. Thus the heat coagulation of the capsular edge produced by DC results in less elasticity than that produced by CCC.

A novel pre-B acute lymphoblastic leukemia cell line with chromosomal translocation between p16(INK4A)/p15(INK4B) tumor suppressor and immunoglobulin heavy chain genes: TGFbeta/IL-7 inhibitory signaling mechanism

p16 INK4A and/or p15 INK4B genes are frequently deleted in leukemias and other cancers. We have established a novel pre-B acute lymphoblastic leukemia (ALL) cell line (JKB2) with a chromosomal translocation between 9p2l and 14q32, on which p16INK4A/p15INK4B and heavy chain immunoglobulin (Ig) genes, respectively, are located. Homozygous deletions of P16INK4A/p15INK4B genes in JKB2 cells were confirmed by polymerase chain reaction, and their protein products were not detectable by Western blotting. Therefore JKB2 is the first example of an immunoglobulin heavy chain translocation associated with deletions of these genes. In JKB2 cells, cyclin-dependent kinase(CDK)4 and CDK6 formed complexes with cyclin D, due to the lack of p16, triggering phosphorylation of retinoblastoma protein (pRB) and continuous cell proliferation. Moreover, the growth of JKB2 cells was partially inhibited by TGF beta or IL-7, accompanied by decreased CDK4 and CDK6 expression, increased p2l and p27 expression, decreased p27 binding to CDK4/CDK6, and increased binding of p27 to CDK2. In addition, IL-7 both inhibited proliferation and induced differentiation of JKB2 cells. These studies suggest that a t(9;14)(p21;q32) chromosomal translocation can result in deletion of both p16 INK4A and p15 INK4B genes in pre-B ALL, and that the JKB2 cell line therefore provides a model for the study of leukemogenesis related to abnormalities in chromosome 9p2l. Moreover, they suggest that TGF-beta can, suppress JKB2 cell growth in a p15-independent mechanism.

The effects of peripheral serotonin2 (5-HT2) and serotonin3 (5-HT3) receptor agonists on blood glucose levels in rats

The involvement of the peripheral serotonin2A (5-HT2A) receptor in alpha-methyl-5-HT-induced hyperglycemia was examined in rats. The 5-HT2A receptor antagonist, ketanserin, significantly inhibited alpha-methyl-5-HT-elicited hyperglycemia. Taken together with a previous report that 5-HT-induced hyperglycemia was prevented by ketanserin, it is suggested that the peripheral 5-HT2A receptor participates in glucose regulation. As alpha-methyl-5-HT increased serum insulin but did not affect glucagon levels, it is indicated that these pancreatic hormones are probably not related to alpha-methyl-5-HT-induced hyperglycemia. Moreover, the peripheral 5-HT3 receptor agonist, 2-methyl-5-HT, did not affect blood glucose, insulin or glucagon levels. Our results therefore suggest that the peripheral 5-HT3 receptor is not involved in glucose regulation.

Characterization of 42 highly polymorphic bovine microsatellite markers

We have isolated 42 highly polymorphic microsatellite (GT/CA)n markers from Japanese black cattle Wagyu (Bos taurus). Forty-one of the markers were assigned to bovine autosomes with lod scores > 6, through linkage analyses performed on the International Bovine Reference Family Panel (IBRP). The remaining marker showed X-linked inheritance. These markers exhibited an average heterozygosity value of 0.67 with between four and 17 alleles on the IBRP.

Inhibition of human prostate cancer cells growth by gossypol is associated with stimulation of transforming growth factor-beta

Gossypol (GP), an antifertility agent in males, is also capable of inhibiting the proliferation of a wide range of cancer cells in vivo and in vitro. Thus, in this study we investigated the effect of GP on the growth of human androgen-independent prostate cancer cell line (PC3). The results showed that GP acts as a potent inhibitor of PC3 cells as determined by thymidine incorporation assay and flow cytometric analysis. Flow cytometry revealed that treatment of PC3 cells with GP resulted in a dose- and time-dependent accumulation of cells in the GO/GI phase with a concomitant decrease in cells progressing to the S and G2/M phase. These data support our thymidine incorporation results which indicated that GP is a potent inhibitor of PC3 cells. By ribonuclease protection assay, we also investigated the effect of GP on transforming growth factor-beta 1 (TGF-beta 1) gene expression in PC3 cells. Interestingly, the stimulatory effect of GP on TGF-beta 1 gene expression correlates well with its inhibitory effect on PC3 cell DNA synthesis and its ability to arrest cells in GO/G1 phase. Based on these data, it can be concluded that GP is a potent inhibitor of prostate cancer cell growth that acts by arresting cells in GO/G1 phase and that this inhibitory effect may be mediated by TGF-beta 1.

Acid lipase inhibitor in chicken plasma identified as apolipoprotein A-I

We have reported a inhibitor of acid lipases in liver lysosomes and erythrocytes from chickens [M. Fujii et al., Int. J. Biochem., 22, 895-898 (1990)]. In this paper, the properties of the inhibitor were described in comparison with those of apo A-I of chicken. The purified inhibitor migrated with the same mobility on SDS-PAGE as apo A-I, and had a molecular weight of 27,000. The peptide map from the lipase inhibitor was similar to that of apo A-I. Antibodies to the acid lipase inhibitor also reacted with apo A-I. Apo A-I inhibited the acid lipase activities of liver lysosomes and erythrocytes from chickens as strongly as the lipase inhibitor. The N-terminal amino acid sequence of lipase inhibitor was identical to that of apo A-I as far as residue 20. The amino acid sequence of peptides obtained from the inhibitor by cleavage with CNBr corresponded to internal sequence of apo A-I, and so the CNBr-peptides were derived by cleavage after the methionine residues in apo A-I. The findings showed that the inhibitor of the acid lipases in liver lysosomes and erythrocytes from chickens was identical to apo A-I.

Pravastatin reduces restenosis after coronary angioplasty of high grade stenotic lesions: results of SHIPS (SHIga Pravastatin Study)

We conducted a multicenter prospective, randomized, double-blind, placebo-controlled trial to test whether pravastatin, a hydroxymethyl glutaryl coenzyme A reductase inhibitor, can decrease restenosis after percutaneous transluminal coronary angioplasty (PTCA). Pravastatin 10 mg twice daily was begun at least 10 days prior to elective PTCA in patients with total cholesterol less than 280 mg/dl. The end-point was a between-group comparison of the frequency of restenosis defined as a more than 50% loss of the initial gain in diameter stenosis at the PTCA site at 3 months during follow-up by automated quantitative coronary arteriography. Of 207 patients randomly assigned to study groups, 139 patients underwent PTCA; 133 procedures were successful, and 124 patients underwent follow-up angiography at 3 months, and 179 lesions (85 pravastatin, 94 placebo) in 124 patients (62 pravastatin, 62 placebo) were analyzed. The two groups were comparable for baseline characteristics. Total cholesterol decreased by 19.6% in the pravastatin group (p < 0.001) but not in the placebo group. Although the restenosis rate was not different in the two groups (29.4% in pravastatin vs. 39.4% in placebo, p = 0.215) as a whole, it was reduced to about one fifth (8.8%) in the pravastatin group compared with 44.8% in the placebo group (p = 0.0011) when the comparison was restricted to high grade lesions (> or = 75% diameter stenosis, 34 lesions in pravastatin, 29 lesions in placebo). Pravastatin thus reduces restenosis after PTCA of high grade lesions.

Molecular aspects of the structures and functions of the prostaglandin E receptors

Prostaglandin (PG) E2 exerts a variety of biological activities for the maintenance of local homeostasis in the body. The effects of PGE2 are exerted by a variety of PGE receptors which are different in their signal transduction properties and are classified into four subtypes, EP1, EP2, EP3 and EP4. We have isolated the mouse cDNAs for these PGE receptors and characterized the cloned receptors. EP1, EP2, EP3 and EP4 receptors consist of 405, 362, 365 and 513 amino acid residues with a putative seven hydrophobic domains, respectively. When expressed in mammalian cells, EP1 showed elevation of intracellular [Ca2+], EP2 and EP4 stimulated adenylate cyclase and EP3 inhibited the enzyme. Northern blot and in situ hybridization analyses have shown that these subtypes are differently localized to specific tissues and cells. We have identified multiple isoforms of the EP3 receptor (EP3 alpha, EP3 beta, and EP3 gamma) which differ in their carboxy-terminal domains. These isoforms displayed identical agonist binding properties, but were functionally different in the efficiency of G protein activation, the specificity of G protein coupling, and sensitivity to agonist-induced desensitization. The diverse physiological actions of PGE2 are elicited by the molecular diversity of the receptor subtypes and isoforms distributed differently in the body.

Effects of the 5-HT2C/2B receptor agonist 1-(3-chlorophenyl) piperazine on plasma glucose levels of rats

Acute administration of the 5-HT2C/2B receptor agonist 1-(3-chlorophenyl)piperazine (mCPP, 5-10 mg/kg i.p.) induced hyperglycemia in rats. These changes were diminished in a dose-dependent manner by the 5-HT1/5-HT2 receptor antagonist methysergide and the 5-HT2A/2B/2C receptor antagonist ritanserin. In addition, mCPP-induced hyperglycemia was dose dependently diminished by the ganglionic blocker hexamethonium and was prevented by prior adrenodemedullation. Neither the 5-HT2A receptor antagonist ketanserin nor the 5-HT3/5-HT4 receptor antagonist (3-alpha-tropanyl)-1 H-indole-3-carboxylic acid ester (ICS 205-930) proved effective against mCPP-induced hyperglycemia. Lastly, administration of the 5-HT2A/2C receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)2-aminopropane (DOI) increased plasma glucose levels through ketanserin- and ritanserin-sensitive processes. Our results suggest that hyperglycemia elicited by mCPP is mediated by 5-HT2C and/or 2B receptors, and in turn adrenomedullary catecholamine release, whereas that elicited by DOI involves 5-HT2A receptors.

Antitumor activity of a novel podophyllotoxin derivative (TOP-53) against lung cancer and lung metastatic cancer

We synthesized a potent new antitumor podophyllotoxin derivative (4beta-aminoalkyl-4'-O-demethyl-4-desoxypodophyllotoxin; TOP-53) in our search for a drug that has strong activity against lung cancer and lung metastatic cancer. TOP-53 exhibited twice the inhibitory activity of etoposide (VP-16) against topoisomerase II and induced DNA strand breaks but showed no inhibitory activity against tubulin polymerization. The in vitro cytotoxic activity of TOP-53 assessed as IC50 was 0.016-0.37 microg/ml and 0.26-8.9 microg/ml against marine tumor and human non-small cell lung cancer (NSCLC) cell lines, respectively. TOP-53 exerted significant efficacy equivalent to that of VP-16 on s.c.-implanted murine solid tumors (Colon 26, B16-BL6, and Lewis lung carcinoma) at doses 3-5 times lower than that of VP-16. In human tumor xenografts using NSCLC, TOP-53 was active for four of five tumors, whereas VP-16 was active for two of five tumors. Potent inhibitory activity of TOP-53 was also found against a lung tumor (Lewis lung carcinoma) and four lung metastatic tumors (NL-22 and NL-17 colon cancer, UV2237M fibrosarcoma, and K1735M2 melanoma). TOP-53 appeared to be more active against four of them than VP-16. Thus, TOP-53 is not only active against s.c.-implanted lung cancers but also strongly active against lung localized tumor and metastatic tumors in the lungs. The high selectivity of TOP-53 was attributed to its high distribution into the lung and its persistence. TOP-53 is expected to be highly effective against lung cancer including NSCLC and various lung metastatic tumors in the clinical field.

A proteinase inhibitor from egg yolk of hen is an ovoinhibitor analog

A proteinase inhibitor, tentatively termed vitelloinhibitor, was purified from yolk of hen's ovarian follicles. It resembled egg-white ovoinhibitor not only in inhibitory spectrum (active for bovine trypsin and bovine chymotrypsin) but also in thermal stability, pH stability, antiserum reactivity and amino-acid composition. However, vitelloinhibitor had different molecular weight from that of ovoinhibitor. An alpha 2-proteinase inhibitor preparation, isolated from laying hen's serum in the present study, was found to exhibit two bands, and the larger one of the latter corresponded to vitelloinhibitor in molecular weight. The partial N-terminal amino-acid sequence of vitelloinhibitor was the same as those of the two components of serum inhibitor and all three agreed with that of ovoinhibitor. Vitelloinhibitor is likely to be an ovoinhibitor analog derived from a serum precursor, which might be the larger component of alpha 2-proteinase inhibitor.

Experimentally-induced prostatic hyperplasia in young beagles: a model to evaluate the chemotherapeutic effects of gossypol

This study investigated the effect of gossypol on hyperplastic canine prostates induced with long-term administration of androgen and estrogen. Twelve 16-week-old male beagle dogs were divided evenly (n = 3) into 4 treatment groups: (1) CONTROL: vehicle only; (2) Gossypol-Treated: 20 mg/kg gossypol acetic acid; (3) Steroid-Induced: 4 mg/kg testosterone and 40 micrograms/kg estradiol-17 beta; (4) Gossypol-Treated and Steroid-Induced: 4 mg/kg testosterone, 40 micrograms/kg estradiol-17 beta and 20 mg/kg gossypol. The subjects received treatments every other day for 1 month. The beagles treated with steroids developed an acute enlargement (approximately 10-fold) of the prostate as compared to control. The prostatic acini were underdeveloped and characterized by simple squamous to low cuboidal epithelium in the control subjects while acini in steroid-induced subjects were characterized by simple tall columnar epithelium. The subjects treated with gossypol had prostates histologically similar to controls with the exception of loosened periurethral connective tissue. Serum testosterone and estradiol-17 beta levels imply that gossypol can reduce steroid hormonal levels. Mean serum testosterone levels in gossypol-treated subjects were reduced approximately 50% from controls. Serum biochemistry profiles indicate that steroid and/or gossypol treatments were not toxic at the doses and duration used in this study. These observations imply that gossypol and steroid hormones can interact to alter prostate development and gossypol metabolism and/or clearance.

Effects of adrenodemedullation and adrenalectomy on the 5-HT2 receptor agonists DOI-and mCPP-induced hypophagia in rats

Effects of adrenodemedullation and adrenalectomy on the serotonin2 (5-HT2) receptor agonists-induced hypophagia were investigated. Hypophagia induced by both the 5-HT2A/2C, receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and the 5-HT2C-receptor agonist 1-(3-chlorophenyl)piperazine (mCPP) were not affected by adrenodemedullation. In adrenalectomized rats. DOI did not induce hypophagia, while mCPP elicited apparent effects. These results suggest that neither DOI- nor mCPP-induced hypophagia was not associated with adrenaline release from the adrenal medulla. Moreover, our results suggest that DOI-induced hypophagia is involved in corticosterone-sensitive feeding, although other mechanisms which are not related to corticosterone are involved in mCPP-induced anorexia.

Genetic basis of left ventricular remodeling after myocardial infarction

The purpose of the present study was to assess whether the insertion (I)/deletion (D) polymorphism of the angiotensin converting enzyme (ACE) gene, and the polymorphism of angiotensinogen (AGT) gene with threonine (T) instead of methionine (M) at amino acid 235 in exon 2 (M235T) were associated with left ventricular dilatation after myocardial infarction. In 103 patients with myocardial infarction, the left ventricular (LV) end-diastolic volume index (EDVI) and the end-systolic volume index (ESVI) were assessed by echocardiography at two time points, namely at 7 +/- 4 days and at 3.9 +/- 1.3 months (mean +/- S.D.) after the infarction. The increases in the LVEDVI and LVESVI on the second echocardiogram were significantly higher in subjects with the DD and ID genotypes than in patients with the II genotype (P < 0.05 and P < 0.005, respectively). Multiple regression analysis revealed that the LVESVI at the first echocardiographic examination and the ACE I/D genotype were significant predictors of the LVEDVI and LVESVI at the second echocardiographic examination. However, the AGT M235T genotype was eliminated. In conclusion, the DD and ID genotypes of the ACE gene were significantly associated with the progression of the LVEDVI and LVESVI after myocardial infarction. The presence of the deletion allele of the ACE gene may be a risk factor of congestive heart failure after a myocardial infarction.

Keratinocyte growth factor (KGF/FGF-7) has a paracrine role in canine prostate: molecular cloning of mRNA encoding canine KGF

cDNA encoding the canine keratinocyte growth factor (KGF) was cloned from normal canine prostate tissue. The authentic canine KGF cDNA sequence, 686 bp in length, spans the protein-coding region and 88 bp of the 5' and 19 bp of the 3' untranslated regions of canine KGF. The predicted amino acid sequence of canine KGF is composed of 194 amino acid residues. Canine KGF exhibits highest homology with the human KGF cDNA and amino acid sequences (95.8% and 97.4%, respectively), while it demonstrates the lowest homology with the rat sequences at 88.0% and 92.3%, respectively. The degrees of homology with mouse cDNA and amino acid sequences are 91.8% and 95.9%, respectively. By using RNase protection assay, KGF was shown to be expressed in normal prostate tissues of both mature and young (5-month-old) dogs. In vitro, the recombinant canine KGF has mitogenic activity on cultured canine epithelial cells, whereas it has no effect on cultured canine prostatic stromal cells. This novel canine KGF cDNA may be a valuable tool in the study of human benign prostatic hyperplasia using the canine prostatic as a model.

Membrane depolarization by activation of prostaglandin E receptor EP3 subtype of putative serotonergic neurons in the dorsal raphe nucleus of the rat

A whole-cell current-clamp study using a thin slice preparation of the rat brain was carried out to elucidate the function of prostaglandin E (PGE) receptor EP3 subtype in the dorsal raphe nucleus (DR), where mRNA of this subtype is highly expressed. Bath application of PGE2 or M&B 28767, an EP3 agonist, depolarized the membrane of the large DR neurons in a concentration-dependent manner between 10(-9) and 10(-6) M. These neurons showed hyperpolarization of membrane potential to 10 or 50 microM serotonin. Neither an EP2 receptor agonist, butaprost, an EP2/EP4 receptor agonist, 11-deoxy-PGE1, nor an EP1 receptor agonist, 17-phenyl-PGE2, had any effect on large DR neurons between 10(-9) and 10(-6) M. The M&B 28767-induced depolarization was observed in a Ca(2+)-free, high Mg2+ (5 mM) solution containing 0.3 microM tetrodotoxin, and occurred equally well when intracellular Cl- was replaced by gluconate. These results suggest that direct agonist-activation of EP3 receptor depolarizes the membrane by a cationic conductance, leading to excitation of DR neurons, and indicate a physiological implication that EP3 receptor may modulate the serotonergic inhibition of neuronal activities.

Mapping of the genes encoding mouse prostaglandin D, E, and F and prostacyclin receptors

Prostaglandins and prostacyclin are metabolites of arachidonic acid and exert a variety of actions to maintain local homeostasis in the body. Their actions are mediated by cell surface receptors specific to the respective ligands. Using a panel of interspecific back-cross mice, we have mapped the prostaglandin D receptor gene (Ptgdr), prostaglandin E receptor subtype EP(1) gene (Ptgerepl), prostaglandin F receptor gene (Ptgfr), and prostacyclin receptor gene (Ptgir). Ptgdr mapped to proximal Chr 14, Ptgfr mapped to distal Chr 3, Ptgerepl mapped to middle Chr 8, and Ptgir mapped to proximal Chr 7.

Interaction of Shc with adaptor protein adaptins

The role of Shc as a substrate of receptors for growth factors and cytokines is well established. To gain further insight into the function of Shc in signal transduction, we used an affinity method to identify potential Shc-binding proteins. Incubation of bovine brain lysates with a glutathione S-transferase (GST)-Shc fusion protein immobilized on glutathione-Sepharose beads resulted in the binding of cellular proteins of approximately 115, 110, and 100 kDa as well as those of 50 and 17 kDa. Amino acid sequencing of tryptic peptides revealed that the 100-kDa protein was almost identical to beta-adaptin and that the 110- and 115-kDa proteins were almost identical to alphaA-adaptin. Using immunoblot analysis, anti-alpha-adaptin antibody recognized several proteins of 100 approximately 115 kDa, and anti-beta-adaptin antibody recognized a 100-kDa protein, suggesting that alphaA-, alphaC-, and beta-adaptins are bound to the GST-Shc fusion protein. Immunoblot analysis with anti-alpha-adaptin antibody revealed that alpha-adaptin was coimmunoprecipitated with Shc from PC12, KB, and COS cell lysates, suggesting a specific interaction of Shc and adaptins in intact cells. A binding study using mutant GST-Shc fusion proteins revealed that the collagen homologous region (amino acids 233-377) of Shc was required for adaptin binding. Conversely, the collagen homologous region of Shc inhibited the binding of adaptins to GST-Shc. In addition, adaptin was able to bind mutant fusion proteins containing amino acids 233-369, 233-355, 346-369, and 346-355 of Shc, but failed to bind a mutant containing amino acids 233-345, suggesting that amino acids 346-355 (RDLFDMKPFE) in the collagen homologous region of Shc are required for adaptin binding. Thus, this study indicates the specific interaction of Shc with alpha- and beta-adaptin components of plasma membrane adaptor proteins that are thought to be involved in receptor endocytosis.

Mechanism of Bradykinin-induced histamine release from rat peritoneal mast cells

Bradykinin at concentrations higher than 2 microM caused a significant histamine release from rat peritoneal mast cells when extracellular Ca2+ was removed from the medium. Under the same experimental conditions, bradykinin increased Ca2+ release from the intracellular Ca store of the rat peritoneal mast cells, and a clear relationship was observed between the magnitude of histamine release and an increase in fluorescence intensity. Addition of Ca2+ to the medium resulted in an inhibition of the response to bradykinin in a concentration-dependent manner. Almost the same results were obtained when Mg2+, Ba2+ and La3+ were added to the medium. Neither B1 nor B2 antagonists caused significant antagonistic effects on histamine release induced by bradykinin. However, B2 antagonists caused a histamine release of the same potency as bradykinin when applied alone. These results indicate that bradykinin-induced histamine release is not attributable to a bradykinin receptor.

A bicistronic retrovirus vector containing a picornavirus internal ribosome entry site allows for correction of X-linked CGD by selection for MDR1 expression

Chronic granulomatous disease (CGD) is an inherited hematologic disorder involving failure of phagocytic cell oxidase to produce superoxide (O2-.), resulting in recurrent infections. The success of retrovirus gene therapy for hematopoietic diseases will be limited both by the efficiency of ex vivo transduction of target cells and by the ability of corrected cells to replace uncorrected cells in vivo. Using MFG-based retrovirus vectors containing oxidase genes, we have previously demonstrated in vitro correction of CGD, but transduction rates were low. In the present study we explore a strategy for providing a selective growth advantage to transduced cells, while retaining the single promoter feature of MFG responsible for high virus titer and enhanced protein production. We constructed a bicistronic retrovirus producing a single mRNA encoding both the therapeutic gene for the X-linked form of CGD (X-CGD), gp91phox, and the selectable human multidrug resistance gene, MDR1 linked together by the encephalomyocarditis virus internal ribosome entry site (IRES). As a control we constructed a bicistronic vector with the polio virus IRES element and using the bacterial neomycin resistance gene (neor) as the selective element. In Epstein-Barr virus transformed B (EBV-B) cells from an X-CGD patient, a tissue culture model of CGD, we show correction of the CGD defect and complete normalization of the cell population using either of these vectors and appropriate selection (vincristine for MDR1 and G418 for neor). Using a chemiluminescence assay of O2-. production, populations of cells transduced with either vector demonstrated initial correction levels of from less than 0.1% up to 2.7% of normal EBV-B cell oxidase activity. With either construct, cell growth under appropriate selection enriched the population of transduced cells, resulting in correction of X-CGD EBV-B cells to a level of O2-. production equalling or exceeding that of normal EBV-B cells. These studies show that a therapeutic gene can be linked to a resistance gene by an IRES element, allowing for selective enrichment of cells expressing the therapeutic gene. Furthermore, the use of MDR1 as a selective element in our studies validates an important approach to gene therapy that could allow in vivo selection and is generalizable to a number of therapeutic settings.

In situ hybridization studies of prostacyclin receptor mRNA expression in various mouse organs

1. Expression of prostacyclin receptor (IP receptor) mRNA was examined in various mouse organs, and the cells expressing IP receptor mRNA were identified by in situ hybridization studies. Co-localization of mRNA for the IP receptor with that for preprotachykinin A (PPTA), a precursor protein for substance P, with mRNA for the prostaglandin E receptor subtypes (EP1, EP3 and EP4), and with renin mRNA, was examined by double in situ hybridization studies in the dorsal root ganglion and kidney, respectively. 2. IP receptor mRNA was expressed in the thymus and spleen. Expression in the thymus was found exclusively in the medulla, where mature thymocytes expressed transcripts for the IP receptor. Expression in the spleen was found as scattered signals over the white pulp and as punctate signals in the red pulp. The former was found in splenic lymphocytes and the latter in megakaryocytes. 3. IP receptor mRNA was also expressed in the vascular tissues of various organs such as the aorta, coronary arteries, pulmonary arteries and the cerebral arteries, where its expression was confined to smooth muscle cells. No expression was found in veins. In the kidney, IP receptor mRNA was detected in the interlobular arteries and glomerular arterioles but not in the juxtaglomerular (JG) cells which were labelled with the renin mRNA probe. 4. IP receptor mRNA was expressed in about 40% of the neurones in the dorsal root ganglion. Both small- and large-sized neurones were labelled but no labelling was found in the glia. Expression of PPTA mRNA was found in about 30% of total neurones. About 70% of these neurones expressed IP receptor mRNA, and about half of the IP receptor-positive neurones expressed PPTA mRNA. In addition to IP mRNA, mRNAs for EP1, EP3 and EP4 receptors were expressed in about 30%, 50% and 20%, respectively, of the dorsal root ganglion neurones. About 25%, 41% and 24% of the IP receptor-positive neurons co-expressed the EP1, EP3 and EP4 receptor, respectively. 5. These results not only verified IP receptor expression in various cells and tissues known to be sensitive to prostacyclin, but also revealed its expression in other systems, which urges the study of the actions of prostacyclin in these tissues. They also indicated that the actions of prostacyclin on blood vessels and platelets are mediated by the same type of receptor. Absence of IP receptor mRNA in the JG cells suggests that the action of prostacyclin on renin release may be indirect.

Effects of intracerebroventricular injection of histamine and its related compounds on rectal temperature in mice

Effects of intracerebroventricular injection of histamine and its related compounds on rectal temperature were studied in mice. Histamine (0.1-1.0 mu g) and histidine (500-1,000 mg/kg) caused a dose-related hypothermia. H1 agonist, 2-methylhistamine and 2-thiazolylethylamine also displayed a dose-dependent hypothermia. In addition, H2 agonists, 4-methylhistamine and dimaprit elicited a decrease in body temperature. Preinjection of not only H1-antagonists (diphenhydramine and chlorpheniramine) but also H2 antagonists (cimetidine and ranitidine) abolished histamine-induced hypothermia. Either intracerebroventricular or intraperitoneal injection of thioperamide, a histamine H3 antagonist, showed hypothermia. The hypothermic effect produced by intracerebroventricular injection of thioperamide was significantly blocked by (R)-alpha-methylhistamine, a selective H3 agonist. In addition, the effect induced by thioperamide was inhibited by H1 and H2 antagonists, indicating that the H3 receptor also participates in histamine-induced hypothermia.