A new member of the HCO3(-) transporter superfamily is an apical anion exchanger of beta-intercalated cells in the kidney

The kidneys play pivotal roles in acid-base homeostasis, and the acid-secreting (alpha-type) and bicarbonate-secreting (beta-type) intercalated cells in the collecting ducts are major sites for the final modulation of urinary acid secretion. Since the H(+)-ATPase and anion exchanger activities in these two types of intercalated cells exhibit opposite polarities, it has been suggested that the alpha- and beta-intercalated cells are interchangeable via a cell polarity change. Immunohistological studies, however, have failed to confirm that the apical anion exchanger of beta-intercalated cells is the band 3 protein localized to the basolateral membrane of alpha-intercalated cells. In the present study, we show the evidence that a novel member of the anion exchanger and sodium bicarbonate cotransporter superfamily is an apical anion exchanger of beta-intercalated cells. Cloned cDNA from the beta-intercalated cells shows about 30% homology with anion exchanger types 1-3, and functional expression of this protein in COS-7 cells and Xenopus oocytes showed sodium-independent and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid-insensitive anion exchanger activity. Furthermore, immunohistological studies revealed that this novel anion exchanger is present on the apical membrane of beta-intercalated cells, although some beta-intercalated cells were negative for AE4 staining. We conclude that our newly cloned transporter is an apical anion exchanger of the beta-intercalated cells, whereas our data do not exclude the possibility that there may be another form of anion exchanger in these cells.

Our recent studies on sensory transduction: from vision to taste

The transduction in photoreceptors and chemoreceptors has common mechanisms. In photoreceptors, activation of rhodopsin by light triggers the enzymatic cascade mediated by a G-protein, transducin. In olfactory cells activation of the receptor molecule by odorant triggers the enzymatic cascade mediated by a G-protein, Golf. In taste receptor cells biochemical studies have also suggested a metabotropic transduction hypothesis, but we recently identified a cationic channel that was directly gated by a bitter taste substance. By reviewing these recent studies carried out in our laboratory in the last 10 years, the transduction machinery in these sensory receptor cells are summarized.

Effect of extracellular Ca2+ on the quinine-activated current of bullfrog taste receptor cells

The bitter substance quinine activates a cation current from the frog taste receptor cell. We have analysed the noise associated with this current, and the effect of extracellular Ca2+ on the current, using whole-cell recording on single dissociated cells. Quinine induced an inward current from the taste receptor cell near the resting potential. The response was accompanied by an increase in current fluctuations. From the variance/mean ratio of the quinine-activated current, the single-channel conductance was estimated to be 12 pS in the nominal absence of extracellular Ca2+. In the presence of 1.8 mM Ca2+, this conductance decreased to 5 pS. These values broadly agree with those previously obtained from excised, outside-out membrane patches. The dependence of the current on quinine concentration had a K1/2 of 0.48 mM in the absence of extracellular Ca2+, consistent with measurements from excised patches. The K1/2 value increased to 2.8 mM in 1.8 mM external Ca2+. The maximum current induced by quinine was also reduced by about 20% by Ca2+. The spectral power density distribution of the quinine-activated current could be described by the sum of two Lorentzian functions, with corner frequencies not substantially different in the absence and presence of 1.8 mM external Ca2+. The above results lend further support to the notion that the major component of the response of frog taste receptor cells to quinine comes from an ion channel directly activated by quinine.

Hepatic resection for liver metastasis of sigmoid colon cancer after incomplete percutaneous microwave coagulation therapy

We report a case of colon cancer with liver metastasis that had been treated previously by sigmoidectomy and partial hepatic segmentectomy. A 55-year-old woman presented with two asynchronous liver metastases, which were treated with percutaneous microwave coagulation therapy. However, evaluation by dynamic computed tomography one week later showed incomplete necrosis in at least one tumor. Surgical resection was subsequently performed and histopathological examination showed the presence of viable cancer cells in both tumors. We conclude that surgical resection is perhaps the best curative method of treatment of metastatic liver tumors of colorectal carcinomas and that dynamic computed tomography is not always accurate for evaluating the effect of microwave coagulation therapy.

Cytokine requirement for the development of T-lymphoid lineage potential in clonal lymphohaematopoietic progenitors in vitro

The early process of T-cell development prior to thymic colonization has been poorly investigated because of the lack of a sensitive assay. We have developed a two-step in vitro culture system by combining a clonal culture with a fetal thymus organ culture (FTOC) and analysed the early development of T cells from lymphohaematopoietic progenitors. Cells of immature colonies derived from bone marrow cells of 5-fluorouracil (5FU)-treated mice using various combinations of early acting cytokines were transferred into a FTOC. All the combinations of stem cell factor (SCF), interleukin (IL)-3 and IL-6 capable of inducing colony formation supported T-cell generation. IL-11 and the Flt3 ligand possessed T-lineage promotional effects similar to IL-6 and SCF respectively. However, there were some quantitative differences in the final T-cell yield among cytokine combinations. Thus, the commitment towards T lineage in lymphohaematopoietic progenitors may be an event determined intrinsically rather than induced by specific stimuli, but there may be a hierarchy between the activity of cytokines in further development. Furthermore, we examined the T-lineage potential of individual colonies derived from Lin(-)c-Kit(+)Sca-1(+) cells clone-sorted from post-5FU marrow cells. No colonies that contained only myelocytic progenitors showed T-lineage potential, but 23.3% of colonies with a haematopoietic multipotentiality did. Therefore, the divergence of the T lineage from other lineages such as myeloid potential may occur at an early stage of the hierarchy of haematopoiesis. The proposed method should prove valuable for exploring the molecular and cellular changes that occur during early T-cell development before thymic colonization.

Retreatment with interferon for chronic hepatitis C after transient response

Approximately half of all patients with chronic hepatitis C show an initial biochemical response to interferon, but only 15% to 20% of patients achieve a sustained response. We studied the efficacy of retreatment with interferon for patients with chronic hepatitis C who showed transient biochemical responses to initial treatment. Thirty patients who relapsed were retreated 1 to 52 months (median 14) after the end of initial treatment, according to the previously used regimens. The responses were correlated with the pre-retreatment patient data. The liver histologic grades, compared with those found before the initial treatment, were better in eight (27%) patients but worse in six (20%), whereas the fibrosis stage was improved in five (17%) but worsened in eight (27%). All patients displayed end-of-retreatment biochemical responses. Of the 30 patients, 10 (33%) achieved sustained aminotransferase normalization and serum hepatitis C virus (HCV) RNA clearance, but the remaining 20 patients showed relapse within 1 year after cessation of retreatment. Univariate analysis associated the sustained response with low pre-retreatment viral loads (0.8 +/- 0.7 MEq/mL vs. 9.1 +/- 6.5 MEq/mL; p = 0.006), short treatment intervals (13 +/- 13 months vs. 22 +/- 14 months; p = 0.031), and low histologic grades (1.3 +/- 0.7 vs. 1.9 +/- 0.7; p = 0.039). However, multivariate analysis indicated that only the pre-retreatment viral load was predictive of the sustained response (p = 0.049). These findings suggest that transient responders to interferon are likely to respond to retreatment but the achievement of a sustained response depends on the HCV viral load before retreatment.

Malaria eradication on islands

BACKGROUND

To be successful, a malaria control programme needs to be tailored to the local epidemiological characteristics. Vanuatu consists of 80 inhabited islands in the Southwest Pacific, with hypoendemic and mesoendemic malaria and suitable conditions for sustained parasite elimination. We aimed to assess whether malaria can be eliminated on isolated islands.

METHODS

Weekly mass drug administration of chloroquine, pyrimethamine/sulfadoxine (Fansidar), and primaquine was carried out on the entire population of 718 inhabitants of Aneityum island for 9 weeks in 1991 before the onset of the rainy season. Simultaneously with the administration of drugs, permethrin-impregnated bednets were distributed to the entire population. Larvivorous fish were also introduced into several identified breeding sites of Anopheles farauti. Periodic malariometric monitoring has continued for the past 9 years. Two additional islands of Vanuatu, one with and one without malaria transmission, have been monitored for comparison.

FINDINGS

High community involvement as measured by drug compliance (88.3%) and bednet provision (0.94 nets per villager) has resulted in sustained interruption of malaria transmission in Aneityum. The surveys showed complete absence of Plasmodium falciparum after mass drug administration, and P. vivax disappeared from 1996 onwards, with the exception of two instances of imported infections (one mixed infection in 1993 and one P. vivax infection in 1999).

INTERPRETATION

Malaria can be eliminated on isolated islands with well-adapted short-term mass drug administration and sustained vector control if there is a high degree of community participation.

The diagnostic value of 123I-IMP SPECT in non-Hodgkin's lymphoma of the central nervous system

N-isopropyl-p-[123I]iodoamphetamine (IMP) SPECT is of low diagnostic value in patients with brain tumors, because brain tumors are visualized as uptake defects. Some reports have described non-Hodgkin's lymphoma of the central nervous system (CNS) as showing high uptake on delayed 123I-IMP SPECT images, suggesting its usefulness in diagnosing CNS lymphoma. In this study, we investigated the clinical value of 123I-IMP SPECT as a diagnostic tool for CNS lymphoma.

METHODS

Ninety-six patients with brain tumors, including 12 patients with CNS lymphoma, underwent 123I-IMP SPECT. Eleven patients had primary CNS lymphoma, and 1 had a parenchymal brain metastasis from a breast lymphoma. The total number of lesions was 18, 14 of which were in the cerebral parenchyma, 3 in the brain stem, and 1 in the ventricle. Early SPECT images were initiated 15-30 min after intravenous injection of 111 MBq 123I-IMP, and delayed images were collected 4 h later. SPECT images were visually analyzed with a color-grading scale. Tumor-to-normal activity ratio (T/N) and tumor-to-cerebellum activity ratio (T/C) were calculated for both early and delayed images for semiquantitative analysis.

RESULTS

By visual estimation, more than a 3-cm3 volume of CNS lymphoma was detected as an obvious focus of increased accumulation on delayed images. All other brain tumors tested appeared as decreased accumulation on delayed images. T/Ns and T/Cs on delayed images of CNS lymphomas, including tumors less than 3 cm3 in volume, were 1.48+/-0.42 and 1.08+/-0.16, respectively. These ratios in patients with glioma (0.30+/-0.05 and 0.31+/-0.07 respectively) or meningioma (0.34+/-0.10 and 0.41+/-0.17, respectively) showed a significant difference from those in patients with CNS lymphoma (P < 0.0005).

CONCLUSION

123I-IMP SPECT is a helpful tool for diagnosing CNS lymphoma.

[A case of giant sebaceous gland carcinoma without adequate treatment]

BACKGROUND

A patient with a sebaceous gland carcinoma without adequate treatment is reported.

CASE

A 67-year-old man underwent an operation on his left upper eyelid after a diagnosis of chalazion in 1981. Two years after the initial operation, he noticed a tumor in the left upper eyelid. In 1987, he visited another hospital and was diagnosed with sebaceous gland carcinoma by a tissue biopsy. He left it untreated against medical advice. When he visited our hospital in 1996, the tumor was as large as 80 x 75 x 40 mm and the left upper and lower eyelids stuck together. After admission, he died of myocardial infarction 23 days after his visit to our hospital. Autopsy revealed that the tumor had extended into the orbital cavity, paranasal sinus, and base of the skull, with metastasis to the preauricular, submandibular, and cervical lymph nodes and both lungs. The pathology of the tumor was a moderately differentiated sebaceous gland carcinoma.

CONCLUSION

This case showed the natural course of extension and metastasis of a sebaceous gland carcinoma.

GABA-Mediated inhibition between amacrine cells in the goldfish retina

Retinal amacrine cells have abundant dendro-dendritic synapses between neighboring amacrine cells. Therefore an amacrine cell has both presynaptic and postsynaptic aspects. To understand these synaptic interactions in the amacrine cell, we recorded from amacrine cells in the goldfish retinal slice preparation with perforated- and whole cell-patch clamp techniques. As the presynaptic element, 19% of the cells recorded (15 of 78 cells) showed spontaneous tetrodotoxin (TTX)-sensitive action potentials. As the postsynaptic element, all amacrine cells (n = 9) were found to have GABA-evoked responses and, under perforated patch clamp, 50 microM GABA hyperpolarized amacrine cells by activating a Cl(-) conductance. Bicuculline-sensitive spontaneous postsynaptic currents, carried by Cl(-), were observed in 82% of the cells (64 of 78 cells). Since the source of GABA in the inner plexiform layer is amacrine cells alone, these events are likely to be inhibitory postsynaptic currents (IPSCs) caused by GABA spontaneously released from neighboring amacrine cells. IPSCs were classified into three groups. Large amplitude IPSCs were suppressed by TTX (1 microM), indicating that presynaptic action potentials triggered GABA release. Medium amplitude IPSCs were also TTX sensitive. Small amplitude IPSCs were TTX insensitive (miniature IPSCs; n = 26). All of spike-induced, medium amplitude, and miniature IPSCs were Ca(2+) dependent and blocked by Co(2+). Blocking of glutamatergic inputs by DL-2-amino-phosphonoheptanoate (AP7; 30 microM) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX; 2 microM) had almost no effect on spontaneous GABA release from presynaptic amacrine cells. We suggest that these dendro-dendrotic inhibitory networks contribute to receptive field spatiotemporal properties.

MgcRacGAP is involved in the control of growth and differentiation of hematopoietic cells

In a search for key molecules that prevent murine M1 leukemia cells from undergoing interleukin (IL)-6-induced differentiation into macrophages, we isolated an antisense complementary DNA (cDNA) that encodes full-length mouse MgcRac-GTPase-activating protein (GAP) through functional cloning. Forced expression of this antisense cDNA profoundly inhibited IL-6-induced differentiation of M1 cells into macrophage lineages. We also isolated a full-length human MgcRacGAP cDNA, which encodes an additional N-terminal polypeptide of 105 amino acid residues compared with the previously published human MgcRacGAP. In human HL-60 leukemic cells, overexpression of the full-length form of human MgcRacGAP alone induced growth suppression and macrophage differentiation associated with hypervacuolization and de novo expression of the myelomonocytic marker CD14. Analyses using a GAP-inactive mutant and 2 deletion mutants of MgcRacGAP indicated that the GAP activity was dispensable, but the myosin-like domain and the cysteine-rich domain were indispensable for growth suppression and macrophage differentiation. The present results indicated that MgcRacGAP plays key roles in controlling growth and differentiation of hematopoietic cells through mechanisms other than regulating Rac GTPase activity.

Long-term observations of a patient with choroidal melanoma following fractionated stereotactic radiotherapy: a case report

A 60-year-old man with choroidal melanoma was treated with fractionated stereotactic radiotherapy and followed for 6 years. During this period, the tumor has not changed in size, and the patient has experienced only a slight decrease in visual acuity. In this case, stereotactic radiotherapy appears to have been safe and effective and may also be a cost-effective alternative to particle or plaque therapy.

Thyroid cancer in children: report of three cases and a review of the Japanese literature

We experienced three cases of thyroid cancer in children less than 15 years of age between 1982 and 1995. We herein present these three cases with a review of 141 reported cases of childhood thyroid cancer in Japan. Our patients were 6, 13, and 14 years old. The patients, all girls, were diagnosed as having thyroid cancer based on diagnostic imaging. One of them was also diagnosed by a fine-needle aspiration biopsy (FNAB). One of them underwent subtotal thyroidectomy, and the other two underwent lobectomy. Modified neck dissections were performed on all three. Pathologically, the tumors were all papillary carcinomas. Multiple lymph node metastases were present in all patients. However, the postoperative courses have been good, and there have been no signs of recurrence, 10, 8, and 2 years after their respective operations. In 144 reported cases of childhood thyroid cancer in Japan including ours, the youngest patient was a 2-year-old boy, and the female to male ratio was 2.1:1. FNAB was performed in 25 cases, and 23 (92%) of the tumors were diagnosed as malignant. Histologically, 76% were papillary carcinoma and 20% follicular carcinoma. At operation, lymph node metastases were found in 80% of the cases, and lung metastases in 17%. For treatment, 88% of the patients received a more extensive operation than a lobectomy. Of the 144 patients, 8 died.

[Retinoblastoma]

Hereditary retinoblastoma is different from non-hereditary retinoblastoma in the following ways. It has a germinal mutation of Rb gene located in 13q14. Its inheritance is autosomally dominant with 80% penetrance. Retinal tumors are present usually multiply (average number is three) in both eyes. The patients are found at a younger age than those non-hereditary retinoblastoma. About 5% of them are accompanied by a pineal tumor or paracellular neuroectodermal tumor, in such cases they are called trilateral retinoblastoma. Secondary malignancies such as osteosarcoma and rhabdomyosarcoma are more frequent, and they are the main causes of death of patients with hereditary retinoblastoma. Considering these facts, education of patients and their family members and development of new modalities of treatment for preserving eyeballs without inducing secondary malignancies are important.

Construction of mutants of Sphingomonas paucimobilis defective in terminal mannose in the glycosphingolipid

Mutants of Sphingomonaspaucimobilis defective in a part of the carbohydrate moiety of the glycosphingolipid (GSL) were constructed by transposon (Tn5)-insertional mutagenesis. Defective mutants were selected by ELISA using the antibody recognizing the tetrasaccharide-type GSL (GSL-4A) of S. paucimobilis. Eight defective mutants were selected from about 8,000 kanamycin-resistant strains, and seven of them were found to lack the terminal mannose of GSL-4A. The chemical structure of the mutant GSL was investigated, and proved that the rest of the structure was not changed by the mutation.

Comparison of gyrA and parC mutations and resistance levels among fluoroquinolone-resistant isolates and laboratory-derived mutants of oral streptococci

Laboratory-derived fluoroquinolone-resistant mutants were obtained by serial passage of Streptococcus sanguis and Streptococcus anginosus isolates on agar containing increasing concentrations of old and new fluoroquinolones, ofloxacin and DU-6859a, respectively. Sequencing of an S. sanguis isolate exposed to DU-6859a showed that resistance was associated with two mutations in the quinolone resistance determining region (QRDR) of the gyrA gene (Ser83-->Phe; Glu87-->Lys), and with a mutation in the parC gene (Ser79-->Ile). However, different mutations in the gyrA gene (Ser83-->Tyr) and parC gene (Ser79-->Phe) were found in a S. sanguis isolate exposed to ofloxacin. A fluoroquinolone-resistant isolate, QR-95101, from a dental infection, had a single mutation in the gyrA gene (Ser83-->Phe) and in the parC gene (Ser79-->Phe). Two fluoroquinolone-resistant mutants, QS-701OFm and QS-701DUm, were obtained from S. anginosus QS-701, by exposure to ofloxacin and DU-6859a, respectively. These mutants showed a common substitution at codon 83 (Ser-->Phe) in the gyrA gene but had different substitutions at codon 87 (QS-701OFm, Glu-->Gln; QS-701DUm, Glu-->Lys). They also had different substitutions at codons 79 and 135 in the parC gene (QS-701OFm, Ser79-->Leu but no change at Glu135; QS-701DUm, Ser79-->Ile and Glu135-->Gln). The resistance levels of the DU-6859a-selected resistant S. sanguis mutant QS-951DUm to DU-6859a, ofloxacin, ciprofloxacin and norfloxacin were higher than those of the ofloxacin-selected resistant mutant QS-951OFm. However, ampicillin susceptibilities of these mutants were not different from the parental strains. In S. anginosus, the DU-6859a-selected fluoroquinolone-resistant mutant QS-701DUm was resistant to all the fluoroquinolones tested, while the ofloxacin-selected mutant QS-701OFm was resistant to three fluoroquinolones, but not DU-6859a. The results indicate that different fluoroquinolones select distinct mutations in the QRDR of the gyrA and parC genes in oral streptococci. The gyrA or parC mutation in oral streptococci may determine the levels of fluoroquinolone resistance.

Six-year disease-free survival of a patient with metastatic eyelid squamous cell carcinoma and colon adenocarcinoma after repeated postoperative adoptive immunotherapy

A 74-year-old male was affected concurrently with squamous cell carcinoma of the left eyelid and adenocarcinoma of the colon, both with lymph node metastasis. He underwent exenteration of the left orbit with left modified radical neck dissection and subsequently resection of the transverse colon with regional lymph node dissection. The patient has been treated by an adoptive immunotherapy as a sole postoperative modality without receiving any chemotherapeutic agents causing immunosuppression. For the adoptive immunotherapy, autologous peripheral blood lymphocytes were activated with an immobilized anti-CD3 antibody and IL-2 for 14 days (the CD3-AT cells). The infusion with 1.38 x 10(10) CD3-AT cells has been repeated 150 times in total at the time of writing. Neither recurrence nor additional metastasis has been detected for 6 years after surgery.

Mechanism of liver-selective thyromimetic activity of SK&F L-94901: evidence for the presence of a cell-type-specific nuclear iodothyronine transport process

The thyromimetic compound SK&F L-94901 shows more potent thyromimetic activity in the liver than in the pituitary gland or heart when administered to rats. The mechanisms of liver-selectivity of SK&F L-94901 were examined using cultured rat hepatoma cells (dRLH-84) and rat pituitary tumor cells (GH3), both of which showed saturable cellular uptake of tri-iodothyronine (T(3)). When isolated nuclei with partial disruption of the outer nuclear membrane were used, SK&F L-94901 competed for [(125)I]T(3) binding to nuclear receptors almost equally in dRLH-84 and GH3 cells. SK&F L-94901 also did not discriminate thyroid hormone receptors (TR) alpha1 and beta1 in terms of binding affinity and activation of the thyroid hormone responsive element. In intact cells, however, SK&F L-94901 was a more potent inhibitor of nuclear [(125)I]T(3) binding in dRLH-84 cells than in GH3 cells at an early phase of the nuclear uptake process and after binding equilibrium. These data suggest that SK&F L-94901 is more effectively transported to nuclear TRs in hepatic cells than in pituitary cells and therefore shows liver-selective thyromimetic activity. In conclusion, SK&F L-94901 discriminates hepatic cells and pituitary cells at the nuclear transport process. The cellular transporters responsible for this discrimination were not evident.

Dispersion resulting from phase and amplitude errors in arrayed-waveguide grating multiplexers-demultiplexers

We report dispersion resulting from phase and amplitude errors in arrayed-waveguide grating (AWG) multiplexers-demultiplexers. We measure the phase- and amplitude-error distributions of two different types of AWG and discuss their effects on the dispersion. The results show that the origin of the dispersion in the AWG is the low-order Fourier components of the symmetric phase and the antisymmetric amplitude errors. We also discuss the dependence of the dispersion on the passband shape in the presence of the same fabrication errors.

Acute intrathoracic incarceration of the stomach after laparoscopic Nissen fundoplication

A rare case of paraesophageal hernia with complete intrathoracic incarceration of the stomach after laparoscopic Nissen fundoplication is described. An 85-year-old woman who had undergone laparoscopic Nissen fundoplication for gastroesophageal reflux disease presented 14 months later with nausea and vomiting. Esophagogastroendoscopy showed obstruction of the esophagogastric junction and gastric mucosal necrosis. Emergency laparotomy showed the stomach to be entirely strangulated into the thorax, with areas of necrosis. Gastrotomy was followed by resection of the necrotic anterior wall of the stomach, closure of the hiatus, and suturing of the stomach to the diaphragm. Appropriate closure of crura and anchoring suture between the stomach and diaphragm are helpful to prevent recurrent hernia after laparoscopic Nissen fundoplication.

A method to identify cDNAs based on localization of green fluorescent protein fusion products

We previously established a high-efficiency, retrovirus-mediated expression cloning method. Using this system, we now have developed an expression cloning method (FL-REX; fluorescence localization-based retrovirus-mediated expression cloning) in which cDNAs can be isolated based on the subcellular localization of their protein products. Complementary DNAs generated from mRNA using random hexamers were fused to the cDNA of green fluorescent protein (GFP) in the pMX retrovirus vector. The resulting cDNA-GFP fusion library was transfected into retrovirus-packaging cells, and the derived retroviruses were used to infect NIH 3T3 cells. Infected cells then were screened to identify cDNAs of interest through the subcellular localization of the GFP-fusion products. Using FL-REX, we have identified 25 cDNAs, most of which showed reasonable subcellular localization as GFP-fusion proteins, indicating that FL-REX is useful for identification of proteins that show specific intracellular localization.

Trans-mesosigmoid cutaneous ureterostomy

BACKGROUND

A new method was developed in order to create a single stoma cutaneous ureterostomy in which both ureters traverse the abdominal cavity and yet are buttressed by the mesosigmoid and covered by its visceral peritoneum.

METHODS

The long mesenterium which is attached to the most mobile part of the sigmoid colon was used for the bilateral ureteral pathway. Tunnels for the ureteral path were made just underneath the visceral peritoneum on the bilateral side of the mesosigmoid. Through the tunnels both ureteral ends were brought from the retroperitoneal space to the mesenterocolonic junction (MCJ) and the MCJ is then approximated and sutured to the inside of the ureteral tract through the abdominal wall. The ureters brought outside the skin, are conjoined and sutured to the V skin flap. Eight patients who carried a high risk for operation and/or had a bladder tumor judged to be incurable underwent this cutaneous ureterostomy.

RESULTS

All cases except one with low urinary output could be managed without catheter indwelling during the follow-up period. Three patients suffered from paralytic ileus and one required laparotomy for mechanical ileus during the short postoperative period. Postoperative excretory urography evaluated 14 kidneys during the follow-up period from 2 to 61 months and showed normal upper urinary tract in 11 and a mildly hydronephrotic tract in three.

CONCLUSIONS

Transmesosigmoid cutaneous ureterostomy provides a single catheterless stoma even when the available ureters are relatively short. It appears to be a good method for supravesical urinary diversion when indicated.

Modulation by Zn2+ of GABA responses in bipolar cells of the mouse retina

The localization of endogenous Zn2+ in the mouse retina was examined histochemically and the inhibitory action of Zn2+ on GABA-induced responses was studied in bipolar cells isolated from the mouse retina. Accumulation of endogenous Zn2+ was detected in photoreceptors, bipolar, and/or amacrine cells by either the bromopyridylazo-diethylaminophenol method or the dithizone method. Under whole-cell recording conditions, GABA induced a Cl- current in isolated bipolar cells. The current consisted of two components. The first component was inhibited completely by application of 100 microM bicuculline, suggesting that this is a GABA(A)-receptor mediated current. The second component was inhibited completely by 100 microM 3-aminopropyl-(methyl)-phosphinic acid, suggesting that this is a GABA(C)-receptor mediated current. GABA(C) receptors were present at a higher density on the axon terminal than on dendrites. Zn2+ inhibited both GABA(A) and GABA(C) receptors. GABA(C) receptors were more susceptible to Zn2+; the IC50 for the GABA(A) receptor was 67.4 microM and that for the GABA(C) receptor was 1.9 microM. These results suggest that Zn2+ modulates the inhibitory interaction between amacrine and bipolar cells, particularly that mediated by the GABA(C) receptor.

Tetrodotoxin-sensitive persistent current boosts the depolarization of retinal amacrine cells in goldfish

To light illumination retinal amacrine cells respond with graded depolarization accompanied by a spike discharge. It has been assumed that the graded depolarization is produced solely by the excitatory synaptic inputs from bipolar cells. Here we demonstrate that a tetrodotoxin (TTX)-sensitive persistent current also contributes to the graded depolarization. This current was isolated in amacrine cells of the goldfish retinal slice preparations by the whole-cell patch clamp technique. The activation threshold of the persistent current was about -50 mV, approximately 10 mV more positive than the membrane potential in the dark. Therefore, it is highly likely that the TTX-sensitive persistent current is a booster of the excitatory postsynaptic potential in amacrine cells.

Involvement of cAMP responsive element binding protein (CREB) in the synovial cell hyperfunction in patients with rheumatoid arthritis

OBJECTIVE

To elucidate a possible role of cAMP responsive element binding protein (CREB) in rheumatoid arthritis (RA) synovial cell function, we have studied CREB expression of synovial cells and the effects of an inhibitor of the cAMP/CREB signal pathway on synovial cell function in patients with RA.

METHODS

We examined CREB expression by immunohistochemical staining, immunocytochemical staining, and gel shift assays. Effects of cAMP/CREB inhibitor on the proliferation of RA synovial cells were assessed by [3H]-TdR incorporation, and those on proinflammatory cytokine and matrix metalloproteinase (MMP) production by reverse transcription PCR and ELISAs.

RESULTS

Immunohistochemical staining of synovial tissue revealed that CREB is expressed mainly in the lining and sublining layers of synovium in patients with RA. DNA binding activity of CREB was ascertained by a gel shift assay. We also confirmed nuclear translocation and phosphorylation of CREB in TNF-alpha stimulated RA fibroblast-like synovial cells by immunocytochemical staining. Modulators of cAMP/CREB signaling pathway, such as Rp-cAMP, had an inhibitory potential on RA synovial cell proliferation in vitro. Rp-cAMP also inhibited the proinflammatory cytokine and MMP production.

CONCLUSION

CREB is involved in the synovial cell activity in patients with RA. Inhibition of CREB activity by its inhibitor brings about the correction of aberrant synovial cell functions in patients with RA, thus suggesting a possible clinical application of cAMP/CREB inhibitors.

Enzyme immunoassay for autoantibodies to human liver-type arginase and its clinical application

BACKGROUND

Arginase is an enzyme of the urea cycle, and one of the two isoenzymes is the liver-type enzyme. We examined serum autoantibodies to this liver-type enzyme in patients with hepatitis.

METHODS

Antibodies to recombinant human liver-type arginase were measured by ELISA in 95 patients and 55 healthy controls.

RESULTS

The mean absorbance values in the ELISA assays of patients with definite autoimmune hepatitis (n = 11; P <0.0001), probable autoimmune hepatitis (n = 31; P <0.0001), and hepatitis C (HCV; n = 20; P <0.01) were significantly different from those of healthy controls, but the values in patients with hepatitis B (HBV; n = 23) and other autoimmune diseases (n = 10) were not significantly different from those of healthy controls. When the cutoff was fixed at the upper 95th percentile of the absorbance value in healthy controls, positive reactions were found in 18.2%, 32.3%, 20.0%, 13. 0%, and 10.0% of patients with definite autoimmune hepatitis, probable autoimmune hepatitis, HCV hepatitis, HBV hepatitis, and other autoimmune diseases, respectively. All of these positive reactions were abolished by inhibition of serum with recombinant antigen. The specificity and sensitivity of this ELISA were 96% and 29%, respectively. The intraassay and interassay coefficients of variation were 2.3-7.5% and 9.8-11%, respectively. There was no relationship between these antibodies and anti-nuclear, anti-smooth muscle, or anti-cytochrome P450IID6 antibodies.

CONCLUSIONS

The ELISA for anti-liver-type arginase autoantibody improved the detectability of autoimmune hepatitis when compared with established assays for liver-specific autoantibodies.

Characterization of tissue outgrowth developed in vitro in patients with rheumatoid arthritis: involvement of T cells in the development of tissue outgrowth

BACKGROUND

The aim of this study was to analyze cellular and cytokine interactions governing the development of synovial tissue outgrowth in patients with rheumatoid arthritis (RA).

METHODS

A single-cell suspension of dissociated synovial tissues of RA patients was cultured for a long period to develop tissue outgrowth. The resulting tissue outgrowth was characterized by immunohistochemical staining and ELISA.

RESULTS

The tissue outgrowth developed in vitro included various cell types, such as macrophage-like synovial cells, fibroblast-like synovial cells and lymphocytes. Even after prolonged cultivation, synovial cells devoid of infiltrating T lymphocytes did not form tissue outgrowth. The outgrowth contained CD3+ cells, LeuM3 (CD14)+ cells and HLA-DR+ cells. The T cells expressed lymphocyte function-associated antigen (LFA)-1 and CD2, and the synovial cells expressed intracellular adhesion molecule (ICAM)-1 and LFA-3, suggesting possible interactions via LFA-1/ICAM-1 and CD2/LFA-3. Production of T-cell derived IFN-gamma and IL-17 and synovial-cell-derived fibroblast growth factor (FGF)-1 and IL-15 was confirmed in the tissue outgrowth as well as in RA synovial tissue. These cell types stimulate each other by secreting cytokines, leading to the secretion of proinflammatory cytokines and matrix metalloproteinase (MMP)-1 by the tissue outgrowth and proliferation of both lymphocytes and synovial cells.

CONCLUSION

This study emphasizes the importance of cellular interactions between T cells and synovial cells, via adhesion molecules and the secretion of cytokines with stimulatory activity towards other cell types, for the hyperactivity of RA synovial cells.

Laparoscopic low anterior resection using a triple stapling technique

Laparoscopic low anterior resections using a triple stapling technique in five patients with rectal cancers (four Dukes A and one Dukes C) were performed. The location of the tumors was between 5 and 18 cm from the anal verge. For easy maneuverability, a 33-mm suprapubic port was used. In this technique, the Endo TA (the first stapler) is applied at the distal margin of the rectum to occlude the bowel. The bowel is irrigated with povidone-iodine solution and transected by an endolinear (the second) stapler. Anastomosis is completed by firing the circular (the third) stapler. The operative time was 177 +/- 28.0 minutes, estimated blood loss was 41.7 +/- 28.6 g, and flatus appeared 1.8 +/- 0.8 days after surgery. Follow-up studies have showed no local recurrence or distant metastasis. This procedure is safe and useful for performing laparoscopic low anterior resection.

Evidence for neural regulation of inflammatory synovial cell functions by secreting calcitonin gene-related peptide and vasoactive intestinal peptide in patients with rheumatoid arthritis

OBJECTIVE

To elucidate the possible involvement of the nervous system in the regulation of pathophysiologic responses in patients with rheumatoid arthritis (RA), we examined the expression of peripheral nerves containing the neuropeptides calcitonin gene-related peptide (CGRP) and vasoactive intestinal peptide (VIP) in RA synovium and their effects on RA synovial cell functions.

METHODS

The effects of CGRP and VIP on proinflammatory cytokine and matrix metalloproteinase (MMP) production by RA synovial cells were estimated by enzyme-linked immunosorbent assay, and their messenger RNA (mRNA) expression by reverse transcription-polymerase chain reaction (RT-PCR) using limiting dilutions of the complementary DNA. Expression of CGRP receptors (CGRPRs) and VIP receptors (VIPRs) on RA synovial cells was assessed by RT-PCR and radioreceptor assays. The functions of CGRPRs and VIPRs of the synovial cells were studied by using a CGRPR antagonist and a VIPR antagonist, respectively.

RESULTS

CGRP and VIP inhibited the proliferation of, and the proinflammatory cytokine and MMP production by, RA synovial cells at the level of mRNA expression. Expression of CGRPR and VIPR on RA fibroblast-like synovial cells was confirmed by RT-PCR and radioreceptor assays. Functions of the neuropeptide receptors were inhibited by their receptor antagonists. CGRP and VIP inhibited nuclear translocation and phosphorylation of the transcription factor cAMP response element binding protein in RA synovial cells.

CONCLUSION

CGRP and VIP inhibited excessive synovial cell functions, which suggests neural regulation of inflammatory responses in patients with RA and possible clinical application of the neuropeptides.

Chimeric cytokine receptor can transduce expansion signals in interleukin 6 receptor alpha (IL-6Ralpha)-, IL-11Ralpha-, and gp130-low to -negative primitive hematopoietic progenitors

We generated transgenic mice expressing chimeric receptors, which comprise extracellular domains of the human granulocyte-macrophage colony-stimulating factor (hGM-CSF) receptor and transmembrane and cytoplasmic domains of the mouse leukemia inhibitory factor receptor. In suspension cultures of lineage-negative (Lin(-)), 5-fluorouracil-resistant bone marrow cells of the transgenic mice, a combination of hGM-CSF and stem cell factor (SCF) induced exponential expansions of mixed colony-forming unit. The combination of hGM-CSF and SCF was effective on enriched, Lin(-)Sca-1(+)c-kit(+) progenitors and increased either mixed colony-forming unit or cobblestone area-forming cells. In case of stimulation with hGM-CSF and SCF, interleukin-6 (IL-6) and SCF, or IL-11 and SCF, the most efficient expansion was achieved with hGM-CSF and SCF. When Lin(-)Sca-1(+)c-kit(+)CD34(-) further enriched progenitors were clone sorted and individually incubated in the presence of SCF, hGM-CSF stimulated a larger number of cells than did IL-6, IL-6 and soluble IL-6 receptor (IL-6R), or IL-11. These data suggest the presence of IL-6Ralpha-, IL-11Ralpha-, and gp130-low to -negative primitive hematopoietic progenitors. Such primitive progenitors are equipped with signal transduction molecules and can expand when these chimeric receptors are genetically introduced into the cells and stimulated with hGM-CSF in the presence of SCF.

[A case of Creutzfeldt-Jakob disease exhibiting athetosis in the early stage]

A 68-year-old man was hospitalized on 24 June, 1998 because of visual and gait disturbance. A month before admission, he had been aware of blurred or double vision while watching TV. A few days later, he developed dysphagia and clumsiness in the fingers. His gait became unstable and he exhibited restless finger movements. His shoulders and trunk showed torsion while walking. On admission, he became disoriented and showed rigidity in the legs and athetosis in the bilateral fingers. Routine laboratory findings, thyroid function data, and the serum levels of vitamin B1, B12, Cu, and ceruloplasmin were within the normal ranges. Periodic synchronous discharges (PSD) were observed on electroencephalography. MRI showed T2-high intensity and atrophy of the bilateral caudate nucleus and putamen in addition to the cerebral cortex. 99mTc-ECD-SPECT showed a decrease of local blood flow in the bilateral frontal, right temporal, and bilateral parietal lobes and bilateral thalami. Athetosis became exacerbated and was observed for a month, overlapping with myoclonus. We diagnosed the patient as having CJD because of progressive dementia, myoclonus and PSD. Analysis of the prion protein revealed that codon 129 was Met/Met and codon 219 Glu/Glu by DNA sequences. The patient developed akinetic mutism and rigid contracture, and died of pneumonia on 5 September, 1998. Because athetosis is thought to involve the bilateral caudate nucleus, putamen and thalamus, the findings of diagnostic imaging in this patient might be relative to the clinical symptoms.

High and variable frequencies of CYP2C19 mutations: medical consequences of poor drug metabolism in Vanuatu and other Pacific islands

Cytochrome P450 (CYP) 2C19 is polymorphic with poor metabolizers representing 3-6% of Europeans and Africans, and 13-23% of Asians. Greater than 99% of the poor metabolizer alleles in Asian populations are defined by two single base pair mutations (CYP2C19*2 and CYP2C19*3). We have recently reported an unprecedentedly high prevalence (71%) of CYP2C19-related poor metabolizer genotype individuals and poor metabolism of proguanil on two malarious islands of Vanuatu in eastern Melanesia. To elucidate this further, a total of 5538 individuals from 24 populations on 16 different islands of Vanuatu were genotyped. Of these, 61% had a poor metabolizer genotype (*2/*2, *2/*3 or *3/*3) with substantial variation among the populations (38-79%). The overall frequencies of CYP2C19*1 (wild-type), CYP2C19*2, and CYP2C19*3 were 0.223, 0.633, and 0.144, respectively. A significant linear correlation was observed between heterozygosity and South latitude (r = 0.552, P < 0.05). The genotype frequencies of 21 of the 24 populations were consistent with Hardy-Weinberg expectations (P > 0.05). Comparisons of genetic, linguistic and geographical patterns among populations suggest that short range gene flow is largely responsible for the current distribution of CYP2C19 alleles in Vanuatu. Taken together with previous studies of nuclear genetic loci of Pacific island populations, these data predict that the poor metabolizer genotype is common throughout Polynesia and Micronesia and may be even more prevalent in western Melanesia than in Vanuatu. This suggests that the majority of Pacific Islanders metabolize a wide variety of clinically important drugs to a significantly lower degree than the average European.

Activation by bitter substances of a cationic channel in membrane patches excised from the bullfrog taste receptor cell

1. The response to bitter-tasting substances was recorded in outside-out membrane patches excised from the taste receptor cell of the bullfrog fungiform papilla. 2. Application of a bitter-tasting substance, quinine or denatonium, induced channel openings under conditions in which none of the second messenger candidates or their precursors (e.g. cyclic nucleotide, inositol 1,4,5-trisphosphate, Ca2+, ATP and GTP) were present on either side of the membrane. The response could be recorded > 10 min after excision of the patch membrane. These data suggest that the channel was directly gated by the bitter-tasting substances. 3. No change in response was detected upon addition to the cytoplasmic side of either GDPbetaS (1 mM) or GTPgammaS (1 mM), suggesting that the G protein cascade has no direct relation to response generation. 4. The quinine-induced current was dose dependent. The lowest effective concentration was approximately 0.1 mM, and the saturating concentration was near 1 mM. The dose-response curve was fitted by the Hill equation with a K of 0.52 mM and a Hill coefficient of 3.8. 5. The single channel conductance measured in 120 mM NaCl solution was 10 pS. The channel was cation selective, and the ratio of the permeabilities for Na+, K+ and Cs+ (PNa : PK : PCs) was 1 : 0.48 : 0.39. The unitary conductance was dependent on the extracellular Ca2+ concentration ([Ca2+]o); 9.2 pS in a nominally Ca2+-free solution, and 4.5 pS in 1. 8 mM [Ca2+]o. 6. The dose dependence, the ion selectivity and the dependence of the unitary conductance on [Ca2+]o were almost identical to those of the quinine-induced whole-cell current reported previously, indicating that the channel activity observed in the excised membrane is the basis of the whole-cell current. 7. The present observations suggest the new possibility that the cationic channel directly gated by bitter substances is involved in the bitter taste transduction mechanism.

Prolactin locally produced by synovium infiltrating T lymphocytes induces excessive synovial cell functions in patients with rheumatoid arthritis

OBJECTIVE

To elucidate the role of prolactin (PRL) produced in joints as part of the pathological response of rheumatoid arthritis (RA), we studied PRL production and prolactin receptor (PRLR) expression in RA synovium and its effects on RA synovial cell functions.

METHODS

Proinflammatory cytokine and matrix metalloproteinase (MMP) production by RA synovial cells was estimated by ELISA, Western blotting analysis, and zymography. Expression of PRLR by RA synovial cells and local production of PRL were estimated by reverse transcription polymerase chain reaction and immunohistochemical staining.

RESULTS

PRL enhanced RA synovial cell proliferation. Production of proinflammatory cytokine and MMP was augmented and production of tissue inhibitor of metalloproteinases (TIMP)-1 was inhibited by PRL treatment of RA synovial cells, suggesting that PRL enhances total collagenase activity in the joints. PRLR was exclusively expressed on fibroblast-like synovial cells and lymphocytes infiltrating into the synovium in patients with RA. Both synovium infiltrating T lymphocytes and, to a lesser extent, fibroblast-like synovial cells synthesized PRL, suggesting that PRL acts as a paracrine as well as autocrine activator of RA synovial cell functions. Stimulation of synovial cells by PRL induced rapid translocation of STAT-5 from cytoplasm into nuclei of RA synovial cells, suggesting that transcriptional regulation of RA synovial cell functions by PRL affects STAT-5. Inhibitors of PRL release, such as bromocriptine, inhibited proliferation of proinflammatory cytokines and collagenases by RA synovial cells.

CONCLUSION

Our findings emphasize the importance of PRL, locally produced by infiltrating T lymphocytes, for aberrant synovial cell functions in RA, and suggest possible clinical application of PRL inhibitors.

[In vitro activities of levofloxacin and other antibiotics against fresh clinical isolates]

In this study, the in vitro activity of levofloxacin (LVFX) against 1,020 fresh bacterial clinical isolates was compared with the activities of a range of ofloxacin, ciprofloxacin (CPFX), ampicillin (ABPC), cefaclor, cefpodoxime, methicillin and benzylpenicillin. The clinical isolates except Vibrio cholerae were collected in Japan during 1998 from patients with infectious diseases. MICs were determined using the agar dilution method according to the recommendations by the Japan Society of Chemotherapy. Some isolates of methicillin resistant Staphylococcus aureus (MRSA) and coagulase negative Staphylococcus were resistant to fluoroquinolones, but the MIC50 of LVFX against MRSA was 6.25 micrograms/ml. LVFX was the most active against MRSA among the antibiotics tested. Most of Staphylococcus epidermidis strains were susceptible to the fluoroquinolones. LVFX showed greater activity against all streptococci strains compared with fluoroquinolones tested. In particular, all Streptococcus pneumoniae strains including PRSP were susceptible to LVFX at < or = 1.56 micrograms/ml. Among Enterococcus, ABPC showed superior activity against Enterococcus faecalis but many isolates of Enterococcus species were resistant to ABPC. LVFX was more active against to these Enterococcus species compared with other fluoroquinolones. On the other hand, LVFX and CPFX showed similar activity against isolates of Enterobacteriaceae. CPFX had an MIC50/90 of 0.20, 0.39 microgram/ml and LVFX showed an MIC50/90 of 0.78, 1.56 micrograms/ml against Pseudomonas aeruginosa. LVFX (MIC50/90 0.10, 0.20 microgram/ml) was more active against Acinetobacter species than CPFX (MIC50/90 0.10, 0.39 microgram/ml). Haemophilus influenzae, Branhamella (Moraxella) catarrhalis and V. cholerae were inhibited by low concentration of the fluoroquinolones tested. The MIC90 of LVFX and CPFX were < or = 0.10 microgram/ml against above three species. Some isolates of Neisseria gonorrhoeae and Campylobacter species were moderately resistant to the fluoroquinolones tested but the MIC50 of LVFX and CPFX were < or = 0.39 microgram/ml. Among anaerobes, Propionibacterium acnes was more susceptible than Peptostreptococcus species, and the MIC90 of beta-lactams and fluoroquinolones tested were < or = 0.78 microgram/ml. In conclusion, this study, performed on large number of strains, confirmed an excellent and wide spectrum antibacterial activity of LVFX compared with the fluoroquinolones and beta-lactams tested. And our results suggest that LVFX may be useful in the treatment of various bacterial infections.

Differential effects of human granulocyte colony-stimulating factor (hG-CSF) and thrombopoietin on megakaryopoiesis and platelet function in hG-CSF receptor-transgenic mice

Granulocyte-colony stimulating factor (G-CSF) has been found to act on the neutrophilic lineage. We recently showed that human G-CSF (hG-CSF) has effects similar to early-acting cytokines such as interleukin-3 (IL-3) in the development of multipotential hematopoietic progenitors in transgenic (Tg) mice expressing receptors (R) for hG-CSF. In the present study, we examined the effects of hG-CSF on more mature hematopoietic cells committed to megakaryocytic lineage in these Tg mice. The administration of hG-CSF to the Tg mice increased the numbers of both platelets in peripheral blood and megakaryocytes in the spleen, indicating that hG-CSF stimulates megakaryopoiesis in the Tg mice in vivo. The stimulatory effect of hG-CSF was also supported by the results of studies in vitro. hG-CSF supported megakaryocyte colony formation in a dose-dependent fashion in clonal cultures of bone marrow cells derived from the Tg mice. Direct effects of hG-CSF on megakaryocytic progenitors in the Tg mice were confirmed by culture of single-cell sorted from bone marrow cells. hG-CSF showed a stronger effect on maturation of megakaryocytes in the Tg mice than that of IL-3 alone, but weaker than that of TPO alone. In addition, hG-CSF induced phosphorylation of STAT3 but not Jak2 or STAT5, while TPO induced phosphorylation of both. In contrast to TPO, hG-CSF did not enhance ADP-induced aggregation. Thus, hG-CSF has a wide variety of functions in megakaryopoiesis of hG-CSFR-Tg mice, as compared with other megakaryopoietic cytokines, but the activity of hG-CSF in megakaryocytes and platelets does not stand up to a comparison with that of TPO. Specific signals may be required for the full maturation and activation of platelets.

CD4+ and/or gammadelta+ T cells in the liver spontaneously produce IL-4 in vitro during the early phase of Leishmania major infection in susceptible BALB/c mice

Numerous studies on the cytokine production profile in Leishmania major infected susceptible and resistant mice have been carried out to elucidate the mechanisms of healing or non-healing of this infection. However, many methods may have failed to detect the actual cytokine production in the inflammatory foci. To overcome this problems, the ELISPOT assay was used to examine the spontaneous production of IL-4 and IFN-gamma in vitro by mononuclear cells from the spleen, lymph nodes and liver in L. major-infected susceptible BALB/c and resistant C57BL/6 mice. None of these mononuclear cells spontaneously produced IFN-gamma in either mouse strains in vitro in the absence of the corresponding antigen(s). However, liver mononuclear cells from infected BALB/c mice spontaneously produced IL-4 in vitro in as early as 2 weeks after the infection, but this was not observed in C57BL/6 mice. The IL-4 producing liver lymphocytes consisted of CD4+ and/or gammadelta+ T cells and uncharacterized cells. These results suggest that liver lymphocytes play some role in the establishment of Th2 prevalence in susceptible BALB/c mice, based on the importance of IL.4 production in the early phase of L. major infection in establishing Th2 dominance in this parasite susceptible mouse.

Functional interaction between Oct-1 and retinoid X receptor

The retinoid X receptor (RXR) is a member of the nuclear hormone receptor superfamily and heterodimerizes with a variety of other family members such as the thyroid hormone receptor (TR),1 retinoic acid receptor, vitamin D receptor, and peroxisome proliferator-activated receptor. Therefore, RXR is supposed to play a key role in a ligand-dependent regulation of gene transcription by nuclear receptors. In this study, we have identified the octamer-binding transcription factor-1 (Oct-1) as a novel interaction factor of RXR. In vitro pull-down assays using RXR deletion mutants showed that the interaction surfaces were located in the region encompassing the DNA binding domain (C domain) and the hinge domain (D domain) of RXR. We also showed that RXR interacted with the POU homeodomain but not with the POU-specific domain of Oct-1. Gel shift analysis revealed that Oct-1 reduced the binding of TR/RXR heterodimers to the thyroid hormone response element (TRE). In transient transfection assays using COS1 cells, Oct-1 repressed the T3-dependent transcriptional activity of TR/RXR heterodimers, consistent with in vitro DNA binding data; however, transcriptional activation by Gal4-TR(LBD) (LBD, ligand binding domain), which lacks its own DNA binding domain but retains responsiveness to T3, was not influenced by Oct-1. These results suggest that Oct-1 functionally interacts with RXR and negatively regulates the nuclear receptor signaling pathway by altering the DNA binding ability of the receptors.

Urease-positive thermophilic strains of Campylobacter isolated from seagulls (Larus spp.)

Three strains of urease-positive thermophilic Campylobacter (UPTC), designated A1, A2 and A3, were identified by biochemical characterization after isolation from faeces of seagulls in Northern Ireland in 1996. The biochemical characteristics of the strains were identical to those of strains described previously. Analysis by pulsed-field gel electrophoresis (PFGE) after separate digestion with ApaI and SmaI demonstrated that the respective PFGE profiles were indistinguishable. The PFGE analysis also suggested that the genomes were approximately 1810 kb in length. This is the first example of the isolation of UPTC from flying homoiothermal animals, i.e. from seagulls (Larus spp.).