The G alpha protein GL2 alpha improves the ability to detect the subthreshold expressions of receptors linked to phospholipase C in Xenopus oocytes

Xenopus laevis oocytes showed no electrophysiological responses to acetylcholine (ACh) and had no significant cholinergic receptor sites when prepared under our conditions. However, they were found to acquire robust electrophysiological responsiveness to ACh when bovine GL2 alpha, which is a member of the Gq alpha family and is highly homologous to mouse G11 alpha, was expressed by mRNA injection. Further analyses indicated that GL2 alpha amplified the activity of endogenous muscarinic ACh receptors that are expressed at an otherwise undetectable level, and thus made their detection possible. Thus, GL2 alpha may prove to be an effective method for detecting the activities of phospholipase C-linked receptors which are only marginally expressed. The usefulness of this method was confirmed in the analyses of a chimeric receptor constructed from metabotropic glutamate receptor subtype 1 alpha and muscarinic ACh receptor subtype M1. The chimeric receptor showed no electrophysiological responses to ACh when expressed alone in oocytes, but became responsive to ACh when co-expressed with GL2 alpha.

[Clinical analysis of adjuvant chemotherapy using 5-fluorouracil, leucovorin and cis-diamminedichloroplatinum for patients with advanced and recurrent gastric cancer]

The chemotherapy combining 5-FU, CDDP, and LV was conducted in 17 patients with advanced and recurrent gastric cancer. The regimen consisted of 5-FU (by continual infusion 600 mg/m2/day for 5 days), CDDP (low-dose consecutive drip infusion, 2 hours 20 mg/m2/day for 3 days) and LV (by bolus infusion 20 mg/ m2/day for 5 days). Advanced gastric cancer was found in 12 cases (operation performed in 9 cases and 7 cases resectable) and recurrent in 5 cases. Macroscopic judgment of efficacy in 10 recurrent and inoperable cases revealed CR in 1 patient, PR in 5 patients, NL in 2, and PD in 2 patients. The overall response rate was 60.0%. There were 7 resectable cases, 4 PR patients, 1 MR and 2 NC patients. The overall response rate was 57.1%. Operations were done in 9 of 12 patients with advanced gastric cancer. The histological effects in 7 cases with resectable cases were as follows: 1 patient of grade 0, 2 patients of grade 1a, 3 patients of grade 1b, and 1 patient of grade 2. The main adverse reactions were gastrointestinal symptoms, but in 3 cases thrombocytopenia was found. This chemotherapy for advanced and recurrent gastric cancer shows excellent clinical efficacy.

Early morphologic changes of atherosclerosis induced by ventromedial hypothalamic lesion in the spontaneously diabetic Goto-Kakizaki rat

It is generally thought that typical atherosclerotic lesions do not develop in the rodent. The Goto-Kakizaki (GK) rat is a nonobese strain in which a spontaneous type of non-insulin-dependent diabetes mellitus develops without apparent macroangiopathy. In our previous study, making ventromedial hypothalamic (VMH) lesions in GK rats induced hyperphagia and a further deterioration in glucose metabolism. In the current study, male GK rats in which VMH lesions were made were examined for vascular changes, with special reference to atherosclerotic lesions. Marked hyperglycemia in GK rats with VMH lesions (hereafter referred to as VMH lesion rats) was revealed over an observation period (plasma glucose levels 16 weeks after the operation: VMH lesion GK rats, 19.3 +/- 2.0 mmol/L, vs sham-operated GK rats, 10.1 +/- 1.3 mmol/L; p < 0.0001). Light microscopic observation of the descending aorta in VMH lesion GK rats 16 weeks after the surgery revealed that the intimal thickening and the number of infiltrating cells into the intima were significantly increased as compared with sham-operated GK rats (17531 +/- 3747 microm2 vs 3072 +/- 1192 microm2, p < 0.0001; 15.6 +/- 3.1 per one transverse section vs 6.8 +/- 2.5 per one transverse section, p < 0.0005). Electron microscopic observations demonstrated an increased number of microvilli and lysosomes in endothelial cells, infiltration of macrophages and lymphocytes into the intima, and migration of medial smooth muscle cells into the intima that are considered to be early events in atherosclerosis. These morphologic changes could be induced by a deterioration in glucose metabolism. This rat may thus be useful for studying the process of the initiation of atherosclerosis in diabetes mellitus.

A case of adrenal insufficiency due to acquired hypothalamic CRH deficiency

A 40-year-old woman with adrenal insufficiency was clinically diagnosed and examined with human corticotropin releasing hormone (CRH). This patient with secondary hypo-adrenalism has shown a normal serum cortisol response to exogenous ACTH administration and has been examined with CRH, lysine-vasopressin (LVP) and insulin tolerance test (ITT), respectively. Success in secreting ACTH in response to both CRH and LVP tests, but not ITT, suggests that this disorder was possibly due to a hypothalamic CRH deficiency rather than pituitary corticotroph dysfunction. A combination of the CRH test and ITT has come to play an increasingly significant role in the diagnosis and differential diagnosis of isolated ACTH deficiency syndrome.

Increased phospholipase D activity in human breast cancer

Phospholipase D is believed to play an important role in cell proliferation and tumorigenesis. One of its major functions is to cause a sustained activation of protein kinase C through the primary production of phosphatidic acid from phosphatidylcholine by the enzyme, followed by dephosphorylation forming diacylglycerol. Protein kinase C is known to be activated or translocated in some tumors including breast tumors. In order to examine phospholipase D activity in breast tumors, surgical specimens of human breast tumors were obtained by mastectomy or wide excision, and their phospholipase D activities were assayed by determining the formation of phosphatidylethanol from phosphatidylcholine and ethanol. Phospholipase D activity was predominantly localized in the microsomal fraction of the tumor tissue and markedly stimulated by oleic acid. We observed a significant increase in phospholipase D activity in 17 out of 19 spontaneous human breast tumors as compared to adjacent histologically normal breast tissue. The mean specific activity in the tumors was 52.9 +/- 41.8 (SD) pmol min-1 mg protein-1 whereas the value for the normal breast tissue was 34.0 +/- 36.2 (SD) pmol min-1 mg protein-1 (P < 0.01; paired Wilcoxon's rank-sum test). The mean tumor/normal activity ratio was 2.37. Among prognostic factors, the nuclear grade, evaluated according to Schnitt et al., was found to be correlated with the activity ratio. Our results suggest a role for phospholipase D in human breast tumors. An elevation in phospholipase D activity is useful as a potential marker for malignant disease in the breast.

Enhancing effects of binary mixtures of acid with salt on the gustatory neural activity in the clawed toad, Xenopus laevis

Binary mixtures of acid with salt were observed to produce enhancing effects on oral chemoreceptor responses by recording the activity of the whole glossopharyngeal nerve of the clawed toad (Xenopus laevis). The mixtures of HCl with various inorganic salts elicited responses larger than the sum of the responses to individual component chemicals of each mixture. The results indicated that the mixture response was composed of a large HCI response and a negligibly small salt response. The concentration-response curve for HCl shifted toward lower concentrations due to the presence of NaCl without affecting the maximal response, and the Hill constant for the curve was unchanged, suggesting that the binding affinity of protons increases with an increase in the concentration of the mixed NaCl. The enhancing effects of the mixtures of HCl and various monovalent sodium salts having equal ionic strength showed distinct differences among the anion species of the salts. The responses to the mixtures of HCl with typical chloride salts having cations of various valencies depended on the Cl- ion concentration up to 0.1 M, whereas they depended on ionic strength as well, suggesting a possible role of salt cations in the enhancing effects of the mixtures. Thus, the enhancing effects of salts on the acid responses are interpreted mostly in terms of the interaction of the salt anions on the receptor membrane around the receptor sites for acid. The additive role of the cationic activity of the mixed salts, however, is also involved.

Visceral fat accumulation as an important risk factor for obstructive sleep apnoea syndrome in obese subjects

OBJECTIVES

It is well known that obstructive sleep apnoea-(OSA) is frequently associated with obesity. In the current study, we investigated the correlation between abdominal visceral fat accumulation and the presence of OSA in obese subjects.

SUBJECTS

A consecutive series of 37 patients (17 men and 20 women) with primary obesity who were admitted to the Second Department of Internal Medicine. Osaka University Hospital, were investigated Patients with OSA were designated as those whose apnoea index (number of apnoea h-1 of sleep) was more than 5.

MAIN OUTCOME MEASURES

The distribution of body fat was determined using computed tomographic sections. The upper airway dimensions were evaluated with indices obtained by cephalometry in both inspiratory and expiratory phases.

RESULTS

Visceral adipose tissue (AT) area which was measured at the level of the umbilicus, and its ratio to total AT area were both significantly greater in OSA patients as compared with those in non-OSA patients. All subjects whose visceral AT area measured more than 220 cm2 manifested OSA. These two parameters also closely correlated with an increase in apnoea index. A multiple linear regression analysis revealed that the visceral AT area significantly correlated to apnoea index when age, AT mass and lean body mass were taken into account. The fluctuations of the upper airway were significantly greater in the large visceral fat group than in the small visceral fat group.

CONCLUSIONS

These results suggest that visceral fat accumulation is an important risk indicator for OSA in obese subjects.

Plasma ratio of ubiquinol and ubiquinone as a marker of oxidative stress

Oxidative stress is defined as a disturbance in the prooxidant-antioxidant balance in favor of the former and has been suggested to be a relevant factor in aging as well as in different pathological conditions, such as heart attack, diabetes, and cancer. Ubiquinol is very sensitive against oxygen radicals and gives ubiquinone as an oxidation product. Therefore, the ratio of ubiquinol to ubiquinone should be a good marker of oxidative stress because of its definition. A method for the simultaneous detection of ubiquinol-10 and ubiquinone-10 in human plasma is described. Heparinized human plasma was mixed with 5 volumes of methanol and 10 volumes of hexane. After vigorous shaking and centrifugation, the hexane phase (5 microliters) was injected immediately and directly on to reverse-phase HPLC equipped with an on-line reduction column and an electrochemical detector in order to avoid the oxidation of ubiquinol to ubiquinone. It was found that the ratio of ubiquinol-10 to ubiquinone-10 was about 95/5 in human plasma from healthy donors. A significant increase in the oxidized form (ubiquinone-10) content was observed in plasmas of patients with hepatitis, cirrhosis, and hepatoma when compared with normal subjects, suggesting increased oxidative stress in these patients.

Pulse-spray thrombolysis in acutely obstructed coronary artery in critical situations

Pulse-spray thrombolysis (PST) was performed to treat large coronary thrombus in 3 patients in critical situations. The originally developed pump system and a custom infusion catheter (SciMed/Boston Scientific, Maple Grove, MN) were used in combination. Case 1, a 48-yr-old male with extensive anterior myocardial infarction, failed to be recanalized by systemic thrombolysis. He underwent emergent coronary angiography, which revealed proximal occlusion of a large left anterior descending artery (LAD). TIMI 3 flow was achieved after 20 min with 200,000 units of urokinese by PST, followed by balloon angioplasty. In case 2, a 57-yr-old male, subacute stent thrombosis occurred 4 days after two and a half Palmatz-Schatz stents were implanted in mid-LAD. TIMI 3 flow was recovered at 20 min with 240,000 units of urokinese and an additional 72,000 units of rt-PA, followed by redilatation with a quarter-size larger balloon than that used in stent deployment. In case 3, a 70-yr-old male, during ultrasound study for unstable angina, a massive thrombotic complication occurred which occluded the left main trunk. PST was immediately performed under cardiac resuscitation, and the patient recovered from shock after 15 min. TIMI 3 flow was restored after 25 min. Two Palmatz-Schatz stents were implanted after thrombus completely disappeared. There were no complications, including distal embolization, intimal dissection, or bleeding. There was also no recurrence of the ischemic event. PST may be considered a potential treatment modality for coronary artery disease where large thrombus plays a major role.

Cloning and functional expression of a novel isoform of ROMK inwardly rectifying ATP-dependent K+ channel, ROMK6 (Kir1.1f)

We have identified from rat kidney a novel isoform of ROMK/Kir1.1, designated ROMK6/Kir1.1f. ROMK6 was nearly identical to ROMK1, but possessed an 122-bp insertion in the 5' region. Its deduced amino acid sequence was shorter by 19 amino acids than that of ROMK1 in the amino-terminus. Unlike other previously reported ROMK isoforms, ROMK6 mRNA was ubiquitously expressed in various tissues, including kidney, brain, heart, liver, pancreas and skeletal muscle. Xenopus oocytes injected with ROMK6 cRNA expressed a Ba2+-sensitive weakly inwardly rectifying K+ current. These results indicate that ROMK6 is a novel functional K+ channel and might be involved in K+ secretion in various tissue.

Gastrointestinal angiodysplasia in congenital platelet dysfunction

We herein report three cases of repeated massive bleeding from the stomach and small bowel. One patient suffered from both thrombasthenia (type II) and von Willebrand disease (type 1) simultaneously. Two others had Bernard-Soulier's syndrome (BSS). One patient with BSS had bleeding from gastric angiodysplasia and was treated endoscopically by clipping. The other patients had massive bleeding from the small intestine, and had partial resection of the affected small intestine. Histologically, irregular dilatation and proliferation of the blood vessels were demonstrated in the submucosa in bleeding spots from a resected small intestine, and these findings were consistent with the features of acquired angiodysplasia. The development of gastrointestinal angiodysplasia may not only be associated with a dysfunction of von Willebrand factor but also with that of platelets.

Temporal and cell-type specific expression of c-fos and c-jun protooncogenes in the mouse uterus after estrogen stimulation

Employing immunohistochemistry and in situ hybridization, we studied the temporal and cell type specific localization of c-Fos and c-Jun proteins and the corresponding messenger RNAs (mRNAs) elicited by a single 17beta-estradiol (E2) injection in the uteri of castrated adult mice. Cellular expression of mRNAs was in parallel with the synthesis of proteins within 1 h. E2 stimulated the c-fos expression rapidly and transiently in the epithelium and vascular endothelium. A second small peak of c-Fos protein and c-fos mRNA expression occurred around 11-13 h in the epithelium. No detectable amount of c-fos transcript and protein was present throughout the time course (0-24 h) in the stromal and myometrial cells. E2 treatment caused differential c-jun expression in all uterine cell types. In the epithelium, c-jun mRNA and protein expression was decreased during 1-6 h post injection, and thereafter returned showing small peak around 11-13 h. Induction of c-Jun protein and c-jun mRNA was evident in the stromal and myometrial cells at 2-3 h, and then the expression gradually decreased and returned to nearly control level by 24 h. E2 treatment induced rapid and transient activation of c-jun in the vascular endothelium. Present results suggest that transient increase of c-Fos and decrease of c-Jun protein at the early phase and coexpression of these proteins at the late phase contribute the proliferation of endometrial epithelium in mature mice. Furthermore, c-Fos and c-Jun expression in the vascular endothelium at the early phase may participate in the uterine imbibition.

[Comparison between monotherapy with imipenem/cilastatin sodium (IPM/CS) and combinations of IPM/CS and other drugs for treating bacterial infections in patients with hematopoietic disorders]

One hundred and nine patients with infections concurrent with hematopoietic disorders were treated with imipenem/cilastatin sodium (IPM/CS) either alone (IPM/CS monotherapy) or in combination with other antimicrobial drugs (IPM/CS combination therapy). The following results were obtained. 1. One hundred and nine patients were allocated at random to two groups: 53 patients to IPM/CS monotherapy and 56 patients to IPM/CS combination therapy. Fourteen patients (6 and 8 in the 2 groups, respectively) were excluded from the clinical evaluation. There were not significant differences between the two groups with respect to the background. 2. The efficacy rates of the 2 treatments against bacterial infections were as follows: in the IPM/CS monotherapy group, 62.5% in 8 patients with sepsis, 75.0% in 23 patients with fever of undetermined origin (FUO), 50.0% in 10 patients with pneumonia, and 68.3% in the 47 patients, and in the IPM/CS combination group, 85.7% in 7 patients with sepsis, 63.6% in 24 patients with FUO, 50.5% in 8 patients with pneumonia, and 67.4% in the 48 patients. The differences between the two groups were not significant. 3. Among the drugs used in combination with IPM/CS, antibiotics other than penicillins, cephalosporins, and aminoglycosides were used in 12 patients and a high efficacy rate of 91.7% was obtained. 4. Bacteriologically, 19 and 17 strains were isolated from the IPM/CS monotherapy and combination therapy groups respectively, and the eradication rates were 100% and 88.9% respectively. 5. Side effects were noted in 2 patients in the IPM/CS monotherapy group and 7 in the combination therapy group, but all of these resolved after discontinuation or completion of the treatment. The efficacies against severe bacterial infections in the presence of hematopoietic disorders were not different between IPM/CS alone and IPM/CS in combination with other antibiotics. Adverse reactions were uncommon with the monotherapy.

Localization of heparin-binding epidermal growth factor-like growth factor in human coronary arteries. Possible roles of HB-EGF in the formation of coronary atherosclerosis

BACKGROUND

Heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) is a newly identified member of the EGF family. Our previous in vitro studies showed that HB-EGF is a potent mitogen and chemoattractant for vascular smooth muscle cells (SMCs), suggesting the role of HB-EGF in the pathogenesis of atherosclerosis. The purposes of the present study were to investigate the localization of HB-EGF in both normal and atherosclerotic human coronary arteries and to elucidate the possible roles of this growth factor in the formation of atherosclerotic lesions.

METHODS AND RESULTS

The immunohistochemical localization of HB-EGF, SMCs, macrophages, and EGF receptors (EGFRs) was examined in human coronary arteries obtained at autopsy. The medial SMCs of coronary arteries in neonates, infants, and children consistently synthesized HB-EGF protein. In normal adults, however, the relative number of HB-EGF-positive medial SMCs decreased gradually with age after about 30 years of age. In nonatherosclerotic coronary arteries with diffuse intimal thickening, SMCs of the intima, especially those located in the area of the medial side of the intima, were strongly positive for HB-EGF protein. In atherosclerotic plaques of coronary arteries with eccentric intimal thickening, both SMCs and macrophages in and around the core lesions, in addition to the intimal and medial SMCs located adjacent to the plaque, produced HB-EGF protein. A strong immunostaining of EGFRs was observed in these SMCs, suggesting a close association of HB-EGF and EGFR expression.

CONCLUSIONS

These data suggest that HB-EGF might play important roles in the migration of SMCs from the media to the intima, the proliferation of intimal SMCs, and the interaction between SMCs and macrophages in the process of coronary atherogenesis.

Application of a newly developed 3-D deformation measurement system to prosthetic dentistry

A new system for measuring three-dimensional deformation has been developed. The main components of the system are a fixed TV camera and vertically scanning projectors. The advantages of the system are: (1) since there is no mechanical contact between the object and the sensing unit, hardness and form of the object do not have to be considered; (2) the system does not need any precise geometry except for the reproducibility of the vertical scanning stage; (3) the time required for one measurements is extremely short; and (4) the system is not expensive. From the basic experiments for testing accuracy, this system has about +/- 30 microns range deviation against 1000 microns deformation of the object. The system has been applied to investigate the influence of various impression procedures for a removable partial denture on the displacement of the simulated soft mucosal tissue. It is revealed that deformation forms are expressed precisely. Our results suggest that this measurement system is quite useful for research in dentistry and that it could be widely applied.

Expression of the Ets-1 proto-oncogene in human gastric carcinoma: correlation with tumor invasion

The proto-oncogene Ets-1 is a transcription factor known to control the expression of a number of genes involved in extracellular matrix remodeling and has been postulated to play a role in cell migration and tumor invasion. To elucidate the involvement of Ets-1 in human gastric carcinomas, we examined 11 cases of gastric adenoma and 110 cases of gastric carcinoma by immunohistochemistry and compared the degree of Ets-1 expression with the depth of carcinoma invasion. Ets-1 was not expressed either in the normal gastric epithelium or in gastric adenomas. Among the 110 cases with gastric adenocarcinoma, 70 (63.6%) showed positive staining for the Ets-1 protein. In mucosal carcinomas, only 3 of 26 cases (11.5%) showed positive immunostaining for Ets-1. In contrast, 67 of 84 cases (79.8%) with submucosal or more invasive carcinomas showed immunopositivity and intense staining for Ets-1 in the tumor cells. The pattern of Ets-1 immunostaining in mucosal carcinomas was weak and differed from that of other local invasive carcinomas (P < 0.001). Histologically, signet-ring cell and mucinous carcinomas expressed relatively weak positivity for Ets-1. Ets-1 expression correlated significantly with the presence of lymph node metastasis (P < 0.001). In situ hybridization, using an Ets-1 oligonucleotide probe, also confirmed the presence of Ets-1 mRNA in gastric carcinomas. Expression of Ets-1 mRNA was also detected in four different kinds of cultured human gastric carcinoma cell lines by the reverse transcription polymerase chain reaction method. These findings suggest that Ets-1 is overexpressed in gastric mucosal cells that have undergone malignant conversion and that Ets-1 is one of the factors involved in the penetration of gastric carcinoma beyond the muscularis mucosa.

Expression and regulation of G protein-coupled receptor kinase 5 and beta-arrestin-1 in rat thyroid FRTL5 cells

G protein-coupled receptor kinases (GRKs) and arrestins are implicated in homologous desensitization of G protein-coupled receptors. We have recently demonstrated that among six GRKs so far identified, GRK5 is the isoform predominantly expressed in the thyroid and appears to be mainly involved in homologous desensitization of thyrotropin receptor (TSHR) in FRTL5 cells. To further understand the molecular mechanisms of the TSHR desensitization, the expression and regulation of GRKs and arrestins together with those of the TSHR were examined in FRTL5 cells. Northern blot analysis of total RNA from FRTL5 cells with the available rat GRK cDNAs (GRK4, 5, and 6) as probes showed that only GRK5 mRNAs of approximately 3, 8, and 10 kilo bases (kb) in length were detectable. When probed with rat beta-arrestin-1 and beta-arrestin-2 cDNAs, beta-arrestin-1 mRNAs of approximately 7.5 and 2.5 kb long, but no (or possibly faint) approximately 2.4 kb beta-arrestin-2 mRNA, were observed, suggesting that in the thyroid, beta-arrestins appear to be predominantly of beta-arrestin-1 isoform. In studies on TSH-regulation of GRK5, beta-arrestin-1 and TSHR mRNAs, steady-state levels of GRK5 and TSHR mRNAs were 3- to 4-fold lower in the cells grown in the medium with TSH than in those without TSH, while betaarrestin-1 mRNA levels were unchanged. Downregulation of GRK5 and TSHR mRNAs by TSH was further confirmed by dose- and time-dependent experiments. Incubation with 1mM 8BrcAMP, a cAMP analog, for 24h fully reproduced this TSH inhibitory effect. A decrease in GRK5 protein by TSH was also confirmed with Western blot analysis. In summary, these data together with our previous data suggested that GRK5 and beta-arrestin-1 seem to be the isoforms predominantly expressed in the thyroid, and they appear to play a pivotal role in TSHR homologous desensitization. We also demonstrated TSH downregulation of GRKS, but not beta-arrestin-1, expression. Further studies will be necessary to elucidate how these phenomena are linked to thyroid pathophysiology.

Genetic analysis of a Japanese cerebrotendinous xanthomatosis family: identification of a novel mutation in the adrenodoxin binding region of the CYP 27 gene

Cerebrotendinous xanthomatosis (CTX), an autosomal recessive lipid-storage hereditary disorder, is caused by mutations in the sterol 27-hydroxylase gene (CYP 27). A 24-year-old female Japanese CTX patient and her parents were studied for a CYP 27 mutation. Multiple xanthomas were the main complaint of the patient and plasma cholestanol level was markedly elevated. Sterol analysis of a xanthoma biopsy confirmed cholesterol and cholestanol deposition, and the cholestanol accounted for 8.1% of the total sterols. Sterol 27-hydroxylase activity in fibroblasts derived from the patient was undetectable, while the activities in fibroblasts from her mother and father were 54% and 41% of the normal level, respectively. Direct sequence analysis showed a missense mutation of A for G substitution in the CYP 27 gene at codon 362 (CGT 362Arg to CAT 362His) with a homozygous pattern in the patient, and a heterozygous pattern in the parents. The mutation, which eliminates a normal HgaI endonuclease site at position 1195 of the cDNA and is located at the adrenodoxin binding region of the gene, is most probably responsible for the decreased sterol 27-hydroxylase activity in this Japanese CTX family. The combined data strongly support that the primary enzymatic defect in CTX is the disruption of sterol 27-hydroxylase and that the disease is inherited in an autosomal recessive trait.

A method for direct DNA amplification of uncharacterized DNA viruses and for development of a viral polymerase chain reaction assay: application to the red sea bream iridovirus

A method is described for isolating a DNA segment of a virus for which no protein or DNA sequence information is available. This segment can then be used to develop a PCR-based assay for the virus. The method is based on the widespread presence and strong conservation of the ribonucleotide reductase gene among DNA viruses. The validity of the procedure is demonstrated by development of an assay for the fish iridovirus. We report the direct isolation from infected fish of a 738-bp segment of the iridovirus ribonucleotide reductase small subunit gene without prior virus purification. Using the sequence information obtained, a PCR-based diagnostic system was developed for detecting iridovirus infection.

Parathyroid hormone-related peptide in synovial fluid and disease activity of rheumatoid arthritis

To understand the clinical role of parathyroid hormone-related peptide (PTHrP) in rheumatoid arthritis (RA), we analysed the circulatory and synovial fluid (SF) concentrations of the N- and C-terminal regions of PTHrP (N- and C-PTHrP) in RA (n = 38), osteoarthritis (OA, n = 45) and control (n = 11) subjects. The SF level of C-PTHrP was markedly higher in RA compared with control and OA groups, while no differences in circulatory C-PTHrP were present among the three groups. In contrast, the SF level of N-PTHrP was marginally higher in OA patients. C-PTHrP levels in SF correlated significantly with CRP, ESR and SF IL-1 receptor antagonist. To identify the mechanism of elevated PTHrP levels in SF, immunohistochemistry and in situ hybridization of synovial membrane (SM) were performed in each subject. Overexpression of PTHrP was identified in the sublining cells within papillary proliferated SM of RA patients only. Our results indicate that C-PTHrP produced from SM into SF reflects the disease activity in RA.

Epitope-tagging of a functional thyrotropin receptor: detection of the native receptor on intact cells

To facilitate immunological detection of thyrotropin receptor (TSHR), we inserted a c-myc epitope within the unique, 50 amino acid segment of the ectodomain (TSHRmyc). When stably expressed in 293 human embryonal kidney (HEK) cells, TSHRmyc demonstrated high affinity TSH binding and the ability to produce cAMP in response to TSH. Binding of the myc monoclonal antibody 9E10 to 293-TSHRmyc cells could be detected with [125I] anti-mouse IgG. No competition was observed between TSH and 9E10 binding to 293-TSHRmyc. Immunoprecipitation by 9E10 of TSHRmyc revealed TSHR forms of approximately 95 and approximately 100 kDa. Endoglycosidase digestion identified the approximately 95 kDa species as the single chain precursor with high mannose carbohydrate. The approximately 100 kDa single chain receptor contained mature, complex carbohydrate. No smaller species of TSHR subunits or proteolytic fragments was observed. Again TSH did not inhibit immunoprecipitation of TSHRmyc by 9E10. These data demonstrate that the normally functioning c-myc epitope-tagged TSHR can be detected directly and in native form with a readily available anti-myc 9E10 and without the need for prior affinity capture. Lack of competition between 9E10 and TSH suggests that at least part of the 50 amino acid segment in TSHR ectodomain is not a TSH binding site. This epitope-tagged TSHR will be valuable for further studies on the synthesis and trafficking of TSHR.

A new blood compatible and permselective hollow fiber membrane for hemodialysis

The authors have prepared a blood compatible and highly permselective hemodialysis membrane composed of polyether segmented nylon. This block copolymer was synthesized by polycondensation of bis-3-aminopropyl-poly(tetramethylene oxide) (PTMO) and poly(imino-1,3-bismethyl-cyclohexyl-iminoisophtharoyl) (NyBl) prepolymer obtained by polycondensation of 1,3-bis(aminomethyl)cyclohexane (B) and isophthalic acid (I). The molecular weight (MW) calculated from the number of end-groups was 16,000-21,000. In vitro blood compatibility was evaluated in terms of platelet adhesion onto the surface. PTMO-NyBl surfaces showed excellent platelet adhesion preventing properties. The PTMO-NyBl hollow fiber membrane was obtained by a dry-wet spinning process. The membranes had higher permeability coefficients for macromolecules ranging from MW 10,000 to 20,000 than polysulfone hollow fiber membrane (PS membrane), and had acceptably low albumin permeability for use as a dialysis membrane. The ex vivo blood compatibilities of PTMO-NyBl membrane and PS membrane were investigated by extracorporeal circulation in a pig model. The PTMO-NyBl membrane gave excellent results when assessing hemodialysis leukopenia, oxidative burst, and free platelet count decrease.

Identification of two Xenopus laevis genes, xMCM2 and xCDC46, with sequence homology to MCM genes involved in DNA replication

The Schizosaccharomyces pombe genes, nda1 and nda4, are essential for the normal regulation of DNA replication and belong to the MCM gene family. This gene family includes Saccharomyces cerevisiae MCM2, MCM3, MCM5/CDC46 and CDC47, S. pombe nda1, nda4, cdc21 and mis5, and genes encoding human BM28, P1MCM3 and P1.1MCM3 and mouse P1MCM3, most of which are considered to be required for the initiation of DNA replication. We isolated two homologues of the MCM genes, xMCM2 and xCDC46, from a Xenopus laevis cDNA library using the polymerase chain reaction (PCR) method. The predicted amino acid (aa) sequences of xMCM2 and xCDC46 are most similar to those of human BM28 (78% identity) and S. pombe Nda4 (48% identity), respectively. By Western blot analysis using anti-xMCM2 and anti-xCDC46 polyclonal antibodies (Ab) raised against glutathione S-transferase (GST)::xMCM2 or GST::xCDC46 fusion proteins, xMCM2 and xCDC46 were identified as 120- and 95-kDa proteins, respectively. When either xMCM2 or xCDC46 was immunoprecipitated with the specific Ab, the other was also co-precipitated. These results suggest that xMCM2 and xCDC46 physically interact with each other.