Functional Kir7.1 channels localized at the root of apical processes in rat retinal pigment epithelium

1. The inwardly rectifying K+ channel current (IK(IR)) recorded from isolated retinal pigmented epithelial (RPE) cells showed poor dependence on external K+ ([K+]o) and low sensitivity to block by Ba2+. We examined the molecular identity and specific subcellular localization of the KIR channel in RPE cells. 2. The Kir7.1 channel current heterologously expressed in HEK293T cells (human embryonic kidney cell line) showed identical properties to those of the RPE IK(IR), i.e. poor dependence on [K+]o and low sensitivity to Ba2+ block. 3. Expression of Kir7.1 mRNA and protein was detected in RPE cells by RT-PCR and immunoblot techniques, respectively. 4. Immunohistochemical studies including electron microscopy revealed that the Kir7.1 channel was localized specifically at the proximal roots of the apical processes of RPE cells, where Na+,K+-ATPase immunoreactivity was also detected. 5. The middle-distal portions of apical processes of RPE cells in the intact tissue exhibited immunoreactivity of Kir4.1, a common KIR channel. In the isolated RPE cells, however, Kir4.1 immunoreactivity was largely lost, while Kir7.1 immunoreactivity remained. 6. These data indicate that the only IK(IR) recorded in isolated RPE cells is derived from the functional Kir7.1 channel localized at the root of apical processes. Co-localization with Na+,K+-ATPase suggests that the Kir7.1 channel may provide the pathway for recycling of K+ to maintain pump activity and thus is essential for K+ handling in RPE cells.

Localization of a mammalian homolog of diaphanous, mDia1, to the mitotic spindle in HeLa cells

mDia1 is a mammalian homolog of Drosophila diaphanous and works as an effector of the small GTPase Rho. It is a member of the formin homology (FH) proteins and contains the Rho-binding domain and an FH3 region in its N terminus, an FH1 region containing polyproline stretches in the middle and an FH2 region in the C terminus. Several lines of evidence indicate that mDia1 and diaphanous are essential in cytokinesis. mDia1 is present in a large amount in the cytoplasm of both interphase and mitotic cells. Using the instantaneous fixation method that preferentially extracts soluble components, we have analyzed localization of mDia1 in mitotic HeLa cells. Immunocytochemistry using polyclonal anti-mDia1 antibody revealed specific immunofluorescence localized to the mitotic spindle. This localization was seen from prophase to telophase. Western blot analysis also detected anti-mDia1 immunoreactivity in the mitotic spindle fraction isolated from mitotic HeLa cells. Consistently, expression of full-length mDia1 as a fusion protein with green fluorescence protein (GFP) revealed the GFP fluorescence again in the mitotic spindle in HeLa cells. Expression of GFP fusions of various truncated mutants of mDia1 identified that this localization is determined by a 173 amino acid-long sequence between the Rho-binding domain and the FH1 region, which contains the C-terminal part of the FH3 region. Point mutation analysis revealed that Leu(434) and Leu(455) in the FH3 region are essential in localization to the mitotic spindle. Neither electroporation of botulinum C3 exoenzyme nor microinjection of Val14RhoA into mitotic cells affected the localization of endogenous mDia1 to the mitotic spindle, suggesting that mDia1 localizes to the mitotic spindle independent of Rho activity. The present study has thus established the mDia1 localization in the mitotic spindle. This localization suggests a role of mDia1 in the spindle-cleavage furrow interaction during cell division.

Phase I/II study of cisplatin, ifosfamide and irinotecan with rhG-CSF support in patients with stage IIIB and IV non-small-cell lung cancer

PURPOSE

We conducted a phase I/II study in previously untreated patients with stage IIIB or IV non-small-cell lung cancer (NSCLC) to: (1) determine the maximum tolerated dose (MTD) of cisplatin combined with a fixed schedule of ifosfamide and irinotecan with rhG-CSF support; and (2) to determine the overall response rate and median survival of patients entered on this study.

METHODS

Ifosfamide (1.5 g/m2) and irinotecan (60 mg/m2) were administered at fixed doses on days 1-4 and on days 1, 8 and 15, respectively. Cisplatin was given on day 1 at 60 mg/m2 and was increased in 10-mg/m2 increments. This regimen was repeated every 4 weeks. rhG-CSF (nartograstim) was administered subcutaneously at a dose of 1 microg/kg on days 5-18 except on the day of irinotecan treatment.

RESULTS

Between June 1995 and April 1998, 46 patients were registered onto this phase I/II study. The MTD of cisplatin was defined according to toxicity and the dose during three courses was increased. Since at the 80 mg/m2 dose level more than one-third of the patients were treated with dose modification, the dose of 70 mg/m2 was recommended for phase II study. The dose-limiting toxicity was leukopenia. The overall response rate was 62.2% (95% CI 48.0-76.4%, the median response duration was 144 days, and the median survival time was 393 days.

CONCLUSION

For phase II study, we recommend doses of cisplatin 70 mg/m2 on day 1 combined with ifosfamide and irinotecan with rhG-CSF support. Both the response rate and preliminary survival data in this study suggest a high degree of activity of this combination in previously untreated NSCLC.

Combination chemotherapy in patients with malignant pleural effusions from non-small cell lung cancer : cisplatin, ifosfamide, and irinotecan with recombinant human granulocyte colony-stimulating factor support

OBJECTIVES

Malignant pleural effusions develop frequently in patients with non-small cell lung cancer (NSCLC), and the prognosis for these patients is very poor. We evaluated the role of systemic chemotherapy for patients with malignant pleural effusions from NSCLC.

METHODS

We analyzed 34 patients who were found to have malignant pleural effusions in the course of diagnosis of 118 patients enrolled in three consecutive clinical trials on advanced NSCLC assessing combination chemotherapy of cisplatin, ifosfamide, and irinotecan with recombinant human granulocyte colony-stimulating factor support. The objective response in the malignant pleural effusion was evaluated by CT scans every course with the response criteria of the Japan Lung Cancer Society.

RESULTS

All patients had adenocarcinoma. The pleural effusion showed a complete response in 13 patients, a partial response in 7 patients, and no response in 14 patients. In the assessment of the efficacy of the treatment for the measurable primary or metastatic lesions, there was a partial response in 25 patients, no change in 8 patients, and progressive disease in 1 patient. The response rate in pleural effusions was 58.8%, and overall response in mensurable lesions was 73.5%. The median time to response and duration of response for pleural effusions were 54 days and 151 days, respectively. The median survival time and 1-year survival rates were 362 days and 48.5%, respectively.

CONCLUSIONS

Both the response rate and survival data in this retrospective study suggest a high degree of activity of this combination chemotherapy in patients with malignant pleural effusions from NSCLC.

Surgical management of multidrug-resistant tuberculosis

We report surgical resections in 3 patients with active multidrug-resistant tuberculosis. All cases involved strains of Mycobacterium tuberculosis resistant to at least isoniazid and rifampin and patients who were poor candidates for medical therapy alone. We conducted pulmonary resections (partial resection in case 1, lobectomy in case 2, and segmentectomy in case 3). The optimum multiple-drug regimen, based on drug susceptibility studies, was used preoperatively and postoperatively. In all cases, sputum smears and cultures yielded negative results postoperatively, and continue to be negative for Mycobacterium tuberculosis to date. It is recommended that, if localized disease is present and medical treatment is likely to fail, pulmonary resection be conducted for multidrug-resistant Mycobacterium tuberculosis.

Multigenerational cortical inheritance of the Rax2 protein in orienting polarity and division in yeast

Diploid yeast cells repeatedly polarize and bud from their poles, probably because of highly stable marks of unknown composition. Here, Rax2, a membrane protein, was shown to behave as such a mark. The Rax2 protein itself was inherited immutably at the cell cortex for multiple generations, and Rax2 was shown to have a half-life exceeding several generations. The persistent inheritance of cortical protein markers would provide a means to couple a cell's history to the future development of a precise morphogenetic form.

Enhancement of peptone-induced gastric acid secretion in streptozotocin-induced diabetic rats

We compared the acid secretory response to peptone in normal and streptozotocin-induced diabetic rats. Animals were injected with streptozotocin and used after 5 weeks of diabetes with blood glucose levels of >350 mg/dl. Under urethane anesthesia, 2 ml peptone solution (2-8%) was instilled in the stomach through an acute fistula every 30 min. Peptone increased acid secretion in a concentration-dependent manner in normal rats, the maximal response being obtained at 8%. Likewise, the increased acid response was observed in diabetic rats, yet the maximal response observed at 4% was significantly greater than that in normal rats. In both cases, this response was inhibited potently by famotidine as well as YM-022 (a CCKB antagonist) and partially inhibited by atropine. Peptone increased luminal histamine and plasma gastrin levels in both normal and diabetic rats, and the former response was significantly greater in diabetic animals. The altered acid secretion and histamine output in diabetic rats were reverted by insulin treatment. Pentagastrin- but not histamine-induced acid secretion was also increased in diabetic rats. We conclude that peptone-induced acid secretion is increased in diabetic conditions. This phenomenon is insulin-dependent and associated with an enhanced release of histamine but not with an increased sensitivity of the parietal cells.

C-terminal tails of sulfonylurea receptors control ADP-induced activation and diazoxide modulation of ATP-sensitive K(+) channels

The ATP-sensitive K(+) (K(ATP)) channels are composed of the pore-forming K(+) channel Kir6.0 and different sulfonylurea receptors (SURs). SUR1, SUR2A, and SUR2B are sulfonylurea receptors that are characteristic for pancreatic, cardiac, and vascular smooth muscle-type K(ATP) channels, respectively. The structural elements of SURs that are responsible for their different characteristics have not been entirely determined. Here we report that the 42 amino acid segment at the C-terminal tail of SURs plays a critical role in the differential activation of different SUR-K(ATP) channels by ADP and diazoxide. In inside-out patches of human embryonic kidney 293T cells coexpressing distinct SURs and Kir6.2, much higher concentrations of ADP were needed to activate channels that contained SUR2A than SUR1 or SUR2B. In all types of K(ATP) channels, diazoxide increased potency but not efficacy of ADP to evoke channel activation. Replacement of the C-terminal segment of SUR1 with that of SUR2A inhibited ADP-mediated channel activation and reduced diazoxide modulation. Point mutations of the second nucleotide-binding domains (NBD2) of SUR1 and SUR2B, which would prevent ADP binding or ATP hydrolysis, showed similar effects. It is therefore suggested that the C-terminal segment of SUR2A possesses an inhibitory effect on NBD2-mediated ADP-induced channel activation, which underlies the differential effects of ADP and diazoxide on K(ATP) channels containing different SURs.

Phase I study of carboplatin, docetaxel and irinotecan with recombinant human granulocyte colony stimulating factor support in patients with advanced non-small cell lung cancer

A phase I study was conducted in patients with stage IIIB or IV non-small cell lung cancer to determine the maximum tolerated dose (MTD) of irinotecan combined with a fixed schedule of docetaxel and carboplatin with recombinant human granulocyte colony stimulating factor (rhG-CSF) (nartograstim) support. Docetaxel was given at 60 mg/m2 on day 1 with carboplatin. The dose of carboplatin was calculated using the Calvert formula to achieve an estimated AUC of 5.0 mg/ml x min. Irinotecan was administered at a starting dose of 40 mg/m2 on day 1 and increased in increments of 10 mg/m2. rhG-CSF was given at 1 microg/kg on days 5-15. Cycles were repeated every 3 weeks. Between February 1998 and March 1999, 22 patients were enrolled in this phase I study. Five patients were chemotherapy naive. The MTD of irinotecan was 60 mg/m2. Diarrhea was considered to be the dose-limiting toxicity. The irinotecan dose intensity of 16.7 mg/m2/week was low compared with other irinotecan-containing regimens. The overall response rate was 38.1% and median survival was 278 days. Irinotecan 50 mg/m2 in combination with 60 mg/m2 docetaxel and carboplatin on day 1 with rhG-CSF support is recommended for phase II study. The response rate and survival data in this phase I study are encouraging.

Combination chemotherapy of cisplatin, ifosfamide, and irinotecan with rhG-CSF support in patients with brain metastases from non-small cell lung cancer

BACKGROUND

Brain metastases develop frequently in patients with non-small cell lung cancer (NSCLC), and the prognosis for these patients is very poor. We evaluated the role of chemotherapy for patients with brain metastases from NSCLC.

METHODS

We analyzed 30 patients who were discovered to have brain metastases during the diagnosis of 121 patients enrolled in three consecutive clinical trials on advanced NSCLC assessing combination chemotherapy of cisplatin, ifosfamide and irinotecan with rhG-CSF support. Response in the brain lesions was evaluated by contrast-enhanced MRI scans after at least two courses.

RESULTS

Fourteen patients achieved a partial response (PR) but there was no change (NC) in 13 patients and progressive disease (PD) in 1. Among patients with extracranial lesions, 18 had a PR and 11 had NC. The response rate in brain metastases was 50.0%, and that in extracranial primary and metastatic lesions was 62.1%. The median duration of response for intra- and extracranial lesions was 140 and 147 days, respectively. After completing chemotherapy, Gamma Knife radiosurgery was performed on 2 patients in remission and 8 patients at disease progression. The median survival time and 1-year survival rate were 382 days and 56.1%, respectively.

CONCLUSIONS

Both the response rate and survival data in this retrospective study suggest a high degree of activity of this combination chemotherapy in patients with brain metastases from NSCLC.

Enzyme-linked immunosorbent assay for anti-tropomyosin antibodies and its clinical application to various heart diseases

Tropomyosin is one of the key proteins for muscle contraction. We developed an enzyme-linked immunosorbent assay for antibodies to porcine muscle tropomyosin and measured serum anti-tropomyosin antibodies in patients with heart diseases and in normal controls. The mean values of absorbance in the ELISA assay of patients with ischemic heart disease (n=36, P<0.001), dilated cardiomyopathy (n=28, P<0.005), valvular heart disease (n=27, P<0.05), and collagen disease (n=38, P<0.05) were significantly higher than those of normal controls (n=53), but the value in patients with hypertrophic cardiomyopathy (n=19) was not significantly different from that of normal controls. When the cut-off value was fixed at the mean+2 SD of absorbance in normal controls, positive reactions were found in 19.4%, 7.1%, 18.5% and 15.8% of patients with ischemic heart disease, dilated cardiomyopathy, valvular heart disease, and collagen disease, respectively. An inhibition study revealed that anti-tropomyosin antibodies were different from anti-myosin antibodies, but there was a partial cross-reactivity between the two. Thus, there was a weak correlation of the titers of the two types of antibody within the group of heart diseases. These data indicate that measurement of anti-tropomyosin antibodies by ELISA is helpful for detecting autoimmune abnormalities in various heart diseases.

Aggravation of ischemia/reperfusion-induced gastric lesions in streptozotocin-diabetic rats

We examined the influence of diabetes on ischemia/reperfusion-induced gastric damage in rats, in relation to the antioxidative system. Animals were injected with streptozotocin (STZ: 70 mg/kg, i.p.) and used after 5 weeks of diabetes with blood glucose levels of >350 mg/dl. Gastric mucosal blood flow (GMBF) was measured before, during and after 20 min of ischemia (1.5 ml bleeding per 100 g body weight from the carotid artery) followed by a 15-min reperfusion in the presence of acid (100 mM HCI). At the end of each experiment, gastric damage was observed macroscopically. GMBF was reduced by ischemia in all groups of rats, followed by a gradual return after reperfusion. Ischemia/reperfusion produced hemorrhagic lesions in normal rat stomachs in the presence of 100 mM HCl. These lesions were significantly aggravated when the animals were pretreated with diethyldithiocarbamate, an inhibitor of superoxide dismutase (SOD). Ischemia/reperfusion-induced damage was also markedly exacerbated in STZ-diabetic rats, but this aggravation was significantly suppressed by pretreatment with exogenous SOD or glutathione (GSH). Diabetic rat stomachs showed significantly less SOD activity as well as GSH content than normal rat stomachs. In addition, the deleterious influence of diabetes on the gastric ulcerogenic response to ischemia/reperfusion was significantly mitigated by decreasing the blood glucose levels by daily insulin treatment. These results suggest that the gastric mucosa of diabetic rats is more vulnerable to ischemia/reperfusion-induced injury, and the mechanism may be partly accounted for by impairment of the antioxidative system associated with a reduced SOD activity and GSH content.

Lack of gastric toxicity of nitric oxide-releasing aspirin, NCX-4016, in the stomach of diabetic rats

We compared the gastric toxic effect of aspirin (ASA) in both normal and diabetic rats, with that of NCX-4016, a derivative of ASA with nitric oxide (NO) releasing moiety. Animals were injected with streptozotocin and used after 5 weeks of diabetes with blood glucose levels of >350 mg/dl in the presence of omeprazole. Oral administration of ASA (with 150 mM HCl) did not produce damage at 30 mg/kg in the conscious rat but caused hemorrhagic gastric lesions in STZ-diabetic rats. By contrast, NCX-4016 even at 190 mg/kg (a dose equimolar to 100 mg/kg of ASA) did not cause damage in both normal and STZ-diabetic rat stomachs. Plasma salicylic acid levels were not different between normal and diabetic rats after administration of ASA or NCX-4016, though the latter gave significantly lower levels as compared to ASA. Intragastric application of ASA (80 mM in 50 mM HCl) for 30 min caused a reduction of transmucosal PD and increase of luminal H+ loss with a minimal effect on mucosal blood flow (GMBF) in both normal and diabetic rats, yet resulting in much severe damage in the stomach of the latter group. Mucosal application of NCX-4016, however, did not cause PD reduction and luminal H+ loss, but produced a marked hyperemia, resulting in no damage in the stomach of both normal and STZ-diabetic rats. The increased gastric toxicity of ASA in STZ-diabetic rats was significantly mitigated by co-application of a NO donor FK-409 together with ASA, with an increase of GMBF, despite similar degrees of PD reduction and luminal H+ loss being observed. We conclude that NCX-4016 does not have a toxic effect in either normal or diabetic rat stomachs, although the diabetic rat stomach is more vulnerable to ASA-induced damage. NCX-4016, though absorbed more slowly than ASA, counteracts the injurious effect of aspirin on the gastric mucosa, probably by increasing GMBF mediated by NO.

Alkali and alkaline-earth metal ketyl complexes: isolation, structural diversity, and hydrogenation/protonation reactions

The use of hexamethylphosphoric triamide (HMPA) as a stabilizing ligand allowed successful isolation of a series of structurally characterizable alkali metal and calcium ketyl complexes. Reaction of lithium and sodium with one equivalent of fluorenone and reaction of sodium with one equivalent of benzophenone in THF, followed by addition of two equivalents of HMPA, yielded the corresponding ketyl complexes 1, 2, and 11, respectively, as microketyl-bridged dimers. If one equivalent of HMPA was used in the reaction of sodium with fluorenone, a further aggregated complex, the mu3-ketyl-bridged tetramer 3, was isolated, whereas analogous reaction of benzophenone with sodium afforded the trimeric ketyl complex 13, rather than a simple benzophenone analogue of 3. In the reaction of potassium with fluorenone, the use of two equivalents of HMPA gave the tetramer 4, rather than a dimeric complex analogous to 1 or 2. Compared to the tetrameric sodium complex 3, there is an extra HMPA ligand that bridges two of the four K atoms in 4. When 0.5 equiv of HMPA was used in the above reaction, complex 5, a THF-bridged analogue of 4, was isolated. In the absence of HMPA, the reaction of sodium with an excess of fluorenone yielded the tetrameric ketyl complex 6, in which two of the four Na atoms are each terminally coordinated by a fluorenone ligand, and the other two Na atoms are coordinated by a THF ligand. Two bridging THF ligands are also observed in 6. Reaction of 1,2-bis(biphenyl-2,2'-diyl)ethane-1,2-diol (7) with two equivalents of LiN(SiMe3)2 or NaN(SiMe3)2 in the presence of four equivalents of HMPA easily afforded 1 or 2, respectively, via C-C bond cleavage of a 1,2-diolate intermediate. The reaction of calcium with two equivalents of fluorenone or benzophenone in the presence of HMPA gave the corresponding complexes that bear two independent ketyl ligands per metal ion. In the presence of 3 or four equivalents of HMPA, the fluorenone ketyl complex was isolated in a six-coordinate octahedral form (10), while the benzophenone ketyl complex was obtained as a five-coordinate trigonal bipyramid (13). The radical carbon atoms in both benzophenone ketyl and fluorenone ketyl complexes are still in an sp2-hybrid state. However, in contrast with the planar configuration of the whole fluorenone ketyl unit, the radical carbon atom in a benzophenone ketyl species is not coplanar with any of the phenyl groups; this explains why benzophenone ketyl is more reactive than fluorenone ketyl. Hydrolysis of 2 or 11 with 2N HCI yielded the corresponding pinacol-coupling product, while treatment of 2 or 11 with 2-propanol, followed by hydrolysis, gave the pairs fluorenone and fluorenol or benzophenone and benzhydrol, respectively. A possible mechanism for these reactions is proposed.

Serological diagnosis of idiopathic pulmonary alveolar proteinosis

Previously, we reported the specific occurrence of neutralizing autoantibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF) in the bronchoalveolar lavage fluid from 11 Japanese patients with idiopathic pulmonary alveolar proteinosis (I-PAP). The autoantibody was also detected in sera from all 5 I-PAP patients examined. To determine that the existence of the autoantibody is not limited to the Japanese patients, we examined sera from 24 I-PAP patients in five countries and showed that the autoantibody was consistently and specifically present in such patients. Thus, detection of the autoantibody in sera can be used for diagnosis of I-PAP. To establish a simple and convenient method for diagnosis of I-PAP, we developed a novel latex agglutination test using latex beads coupled with recombinant human GM-CSF. GM-CSF binding proteins isolated from the sera using the latex beads were identified as the autoantibodies of IgG(1) and IgG(2). The titer of the autoantibody determined by this test correlated with that determined by ELISA. Agglutination was positive in 300-fold diluted sera from all 24 I-PAP patients, but negative in sera from four secondary PAP patients, two congenital PAP patients, 40 patients with other lung diseases, and 38 of 40 normal subjects. These results establish that the latex agglutination test is a reliable method for serological diagnosis of I-PAP with high sensitivity (100%) and specificity (98%).

Combination of cisplatin, ifosfamide, and irinotecan with rhG-CSF support for the treatment of refractory or relapsed small-cell lung cancer

OBJECTIVE

This study was conducted in refractory or relapsed small-cell lung cancer to determine activity and toxicity of the combination of cisplatin, ifosfamide, and irinotecan with rhG-CSF support.

METHODS

Eighteen patients entered the trial. The median chemotherapy-free interval was 3.1 (range 1.0-14.5) months. Cisplatin (20 mg/m(2)) and ifosfamide (1.5 g/m(2)) were administered on days 1-4, and irinotecan (60 mg/m(2)) was administered on days 1, 8, and 15. In patients who experienced grade 4 hematological toxicity during the prior chemotherapy, the doses of cisplatin and irinotecan were reduced to 15 and 50 mg/m(2), respectively. After 10 patients were entered, cisplatin and irinotecan were administered at doses of 15 and 50 mg/m(2), respectively. This regimen was repeated every 4 weeks. rhG-CSF was administered subcutaneously at a dose of 50 microgram/m(2) from days 50 to 18, except on the day of irinotecan treatment.

RESULTS

All patients could be assessed for response and toxicity. There were 1 complete and 16 partial responses, and an overall response rate of 94.4%. The median survival time of all patients was 339 days, and the 1-year survival rate was 47.5%. Hematological toxicities were significant. Grade 4 neutropenia and thrombocytopenia were observed in 61 and 33% of the patients, respectively. Diarrhea was mild and transient. There was no treatment-related death.

CONCLUSION

The combination of cisplatin, ifosfamide, and irinotecan with rhG-CSF support was highly active for the treatment of refractory or relapsed small-cell lung cancer.

Acid secretory changes in streptozotocin-diabetic rats: different responses to various secretagogues

We examined gastric acid secretion in response to various stimuli in streptozotocin (STZ) induced diabetic rats and characterized the alteration of acid secretory responses in diabetic conditions. Animals were injected STZ (70 mg/kg, intraperitoneally) and used after five weeks of diabetes with blood glucose >350 mg/dl. Under urethane anesthesia, the experiment was performed in a chambered stomach or a whole stomach preparation, and the acid secretion was measured at pH 7.0 using a pH-stat method and by adding 100 mM NaOH. The acid secretion was stimulated by intravenous infusion of either histamine (4 mg/kg/hr), pentagastrin (60 microg/kg/hr), or carbachol (20 microg/kg/hr) or by intraluminal application of peptone solution (4%), or vagal electrical stimulation (2 msec, 3 Hz, 0.5 mA). In normal rats, acid secretion was increased in response to either histamine, pentagastrin, carbachol, peptone, or electrical vagal stimulation. In STZ diabetic rats, however, changes in acid secretion varied depending on the stimuli; the acid response to histamine remained unchanged, but the responses to vagal electrical stimulation or pentagastrin and carbachol were significantly decreased or enhanced, respectively, as compared to normal rats. Likewise, the acid response to peptone was also markedly enhanced in STZ-diabetic rats, and this response was significantly blocked by atropine and YM022 (a CCKB/gastrin antagonist) as well as famotidine in both normal and diabetic rats. Both pentagastrin and carbachol increased the luminal release of histamine in normal rats, and these responses were significantly augmented in STZ-diabetic rats. The altered acid response and histamine release induced by pentagastrin in STZ diabetic rats were partially reversed by daily injection of insulin. These results suggest that STZ-diabetic rats showed different changes in gastric acid secretion in response to various stimuli. The increased acid secretory response may be associated with an enhanced release of mucosal histamine, while the decreased response may be due to vagal neuropathy.

Inhibitory effects of vesnarinone on cloned cardiac delayed rectifier K(+) channels expressed in a mammalian cell line

Vesnarinone, a phosphodiesterase inhibitor, prolongs cardiac action potential duration by inhibiting the delayed rectifier K(+) current, I(K). We examined the effect of this agent on human ether-a-go-go related gene (HERG) and KvLQT1/minK K(+) channels heterologously expressed in human embryonic kidney 293T cells with the whole-cell patch-clamp technique. HERG channel current was inhibited by vesnarinone in a concentration-dependent manner, whereas KvLQT1/minK current was hardly affected by the drug. The inhibition of HERG current by vesnarinone became more prominent and faster as the membrane potential was more depolarized. The properties of inhibition could be described by a first order reaction between the drug and the channel that was apparently independent of HERG channel gating. Although the unbinding rate constant of the drug was constant, the apparent binding rate constant increased as the membrane was more depolarized and the drug concentration was raised. This model also could explain the fast recovery from the drug's effect at hyperpolarized potentials and its rate-dependent inhibition of HERG. Therefore, the effect of vesnarinone on the HERG-K(+) current could be adequately described by a simple kinetic model of drug-channel interaction.

Persimmon leaf extract and astragalin inhibit development of dermatitis and IgE elevation in NC/Nga mice

BACKGROUND

We previously found that persimmon leaf extract contains antiallergic substances that inhibit histamine release by human basophilic cell line KU812 in response to cross-linkage of FcepsilonRI.

OBJECTIVES

The purpose of this study was to identify substances in the persimmon leaf extract that are responsible for the effect and to examine their in vivo effects on the allergic mouse model.

METHODS

HPLC analysis of persimmon leaf extract was done to measure its content. Inhibitory activity of persimmon leaf extract or its major constituent of flavonoids (astragalin) on the histamine release by KU812 cells was examined. To investigate the effects of these substances in vivo, models of passive cutaneous anaphylaxis and atopic dermatitis mice (NC/Nga) were used.

RESULTS

Persimmon leaf extract or astragalin inhibited histamine release from KU812 in response to cross-linkage of FcepsilonRI. Oral intake of both substances dose dependently inhibited passive cutaneous reactions. Moreover, oral administration of these substances to NC/Nga atopic dermatitis-model mice led to a striking suppression of the development of dermatitis, scratching behavior, and serum IgE elevation. Histologic analyses revealed that infiltration of inflammatory cells, especially degranulated mast cells, thickening of the epidermis, and prominent hyperkeratosis, were significantly reduced. Immunologic studies showed that the capacity of spleen T cells to produce both IL-4 and IL-13, but not IFN-gamma, was downregulated by means of oral intake of these substances.

CONCLUSION

This study demonstrates a novel activity of astragalin and the dramatic effect of persimmon leaf extract and astragalin on atopic dermatitis-model mice.

Use of fusion images of I-131 metaiodobenzylguanidine, SPECT, and magnetic resonance studies to identify a malignant pheochromocytoma

Pheochromocytoma is a chromaffin tumor in which 10% are extra-adrenal and 10% are malignant. I-131 metaiodobenzylguanidine (MIBG) scintigraphy has an important role in the identification of these tumors and investigation of metastatic lesions. The authors describe a 36-year-old woman who underwent resection of a malignant left adrenal pheochromocytoma who was thought to have metastases in the liver and para-aortic lymph nodes. Fusion images of I-131 MIBG SPECT and magnetic resonance studies were obtained to properly identify the metastatic lesions. These fusion images helped greatly in subsequent surgery.

Polaprezinc exerts a salutary effect on impaired healing of acute gastric lesions in diabetic rats

We examined the influence of diabetes mellitus (DM) on the healing of HCl-induced gastric lesions and the healing promoting effect of polaprezinc [N-(3-aminopropionyl)-L-histidinato zinc] on these lesions. Studies were performed on rats injected intraperitoneally with streptozotocin (STZ, 70 mg/kg) five weeks prior to experiments. Diabetic rats had blood glucose levels (BGLs) higher than 350 mg/100 ml. Randomly chosen animals were treated subcutaneously with insulin (4 IU/day/rat) starting 1 week after STZ. Animals were given 1 ml of 0.6 N HCl by oral gavage (per os) following 18 hr of fasting; they were fed normally from 1 hr later and killed at various time points after HCl administration. Polaprezinc (3-30 mg/kg) or its components ZnSO4/7H2O and L-carnosine were given orally, twice daily for four days following HCl treatment. Gastric lesions induced by HCl healed macroscopically to quiescence within 10 days. DM and insulin did not affect the development of HCl-invoked gastric lesions, but the healing of such lesions was markedly impaired in animals with DM. Daily administration of insulin returned high BGLs to significantly lower ranges (190-208 mg/100 ml) and markedly antagonized the healing impairment. Polaprezinc (>10 mg/kg) significantly reversed the delay observed in diabetic rats without any notable effects on BGLs or acid secretion. Similar trends were observed with ZnSO4/7H2O or a mixture of ZnSO4/7H2O and L-carnosine, but not by L-carnosine alone. The mucosal expression of insulin-like growth factor-1 (IGF-I) mRNA was significantly lower in diabetic rats, a dysregulation partially corrected by insulin and polaprezinc. In addition, the delayed healing in diabetic rats was also significantly promoted by the repeated subcutaneous administration of rhIGF-I (>10 microg/kg, twice daily) without any notable effect on BGLs or acid secretion. These results suggest that DM exerted a deleterious influence on the healing of acute gastric lesions in both insulin- and zinc-sensitive manner. The salutary effects of polaprezinc on the impaired healing of gastric lesion in STZ-diabetic animals may at least be partly explained by enhancement of mucosal IGF-I mRNA expression in the stomach.

A simple method for detecting plasma propofol

IMPLICATIONS

We measured plasma propofol levels by head space-gas chromatography analysis using solid-phase microextraction. This method saves time, and does not require elimination of interfering substances in the plasma. The coefficient variation was +/-5% to +/-30%. The detection limit was 10 ng/mL.

SAP family proteins

Thus far, five members including Dlg, SAP97/hDlg, SAP90/PSD-95, SAP102, and PSD-93/chapsyn110 which belong to SAP family have been identified. Recent studies have revealed that these proteins play important roles in the localization and function of glutamate receptors and K(+) channels. Although most of them have been reported to be localized to the synapse, only one member, SAP97, is expressed also in the epithelial cells. In this review, we have summarized structural characters of SAP family proteins and discuss their functions in neurons and epithelial cells.

[A phase II study of irinotecan combined with cisplatin in non-small cell lung cancer. CPT-11 Lung Cancer Study Group]

Based upon the results of phase I study of irinotecan (CPT-11) combined with cisplatin (CDDP) on non-small cell lung cancer (NSCLC), a combination phase II study on NSCLC was carried out from Feb., 1992 to Sep., 1992. CPT-11 (60 mg/m2) and CDDP (80 mg/m2) were administered by i.v. drip infusion, with administration schedules of Days 1, 8, 15 and only Day 1, respectively. This therapy course was repeated every 4 weeks. Subjects were NSCLC patients of stage III B or IV disease. Those without prior chemotherapy (Group A) and those with prior therapy (Group B) were enrolled separately. Seventy patients were entered into Group A and 32 patients into Group B. One of the patients of Group A was ineligible. The characteristics of the eligible cases of Group A were: male/female, 51/18; median age, 61 years old; PS 0/1/2, 18/39/12; stage IIIB/IV, 26/43; and adeno/squamous/large, 51/15/3. Those of group B were: male/female, 20/12; median age, 62 years old; PS 0/1/2, 5/18/9; stage I/IIIB/IV, 1/7/24, adeno/squamous/large/ad-sq, 28/2/1/1. Thirty-three patients (47.8%) responded in Group A and B patients (25.0%) responded in Group B. Major adverse reactions (grade 3 or higher) of Group A/Group B were neutropenia (80.3%/73.3%), anemia (35.3%/34.4%), diarrhea (18.8%/28.1%) and nausea/vomiting (34.8%/34.4%). Median survival times for Group A and Group B were 308 and 295 days, respectively. CPT-11 in combination with CDDP is effective against NSCLC, suggesting that further studies are needed to determine the usefulness of this therapy.

Interpretation and enantiomer analysis of methamphetamine abusers' urine and illegally brewed methamphetamine crystals

This study deals with the high-performance liquid chromatographic identification of methamphetamine (MAMP) and amphetamine (AMP) enantiomers (d- and l-forms) in five illicit MAMP crystals and in urine specimens from 30 Japanese MAMP abusers. The analysis revealed that two of the types of crystals have a different optical purity ratio (l/d) and the other three have a single crystal of either the d- or l-enantiomer. The l/d ratios of two types of crystals were 0.04 and 49.4, and no racemic form (l/d = 1.00) was found. The urinary analysis showed that nonmetabolized MAMP and its demethylated metabolite, AMP, were present in urine specimens of all addicts. The stereoisomeric profiles in urine can be classified roughly into five groups according to the detected amount and the l/d ratio of MAMP and AMP enantiomers collected at one time point. In the first group, only d-MAMP and d-AMP were detected (in 16 cases). In the second group, only l-MAMP and l-AMP were detected (in one case). In the third group, the amount of the l-enantiomer detected, for both MAMP and AMP, was less than that of the d-enantiomer, and the l/d ratio was between 0.004 and 0.54 for MAMP and between 0.01 and 0.07 for AMP (in five cases). In the fourth group, the l-enantiomer of MAMP and AMP was found to be more abundant than the d-enantiomer, and the l/d ratio was between 2.63 and 30.11 for MAMP and between 1.23 and 31.30 for AMP (in four cases). In the fifth group, the amount of l-MAMP detected was greater than that of d-MAMP, and less l-AMP than d-AMP was detected. The l/d ratios were between 1.13 and 8.82 for MAMP and between 0.17 and 0.82 for AMP (in four cases). These results might be suitable for identification and the forensic toxicological investigation of AMP analogues.

[Efficacy and safety of cefozopran (CZOP) monotherapy and combination therapy with CZOP and amikacin (AMK) for infections accompanying hematological diseases]

We evaluated efficacy and safety of monotherapy with CZOP (1-2 g x 2/day) and combination therapy with CZOP (1-2 g x 2/day) and AMK (200 mg x 2/day) for infections in patients with hematological diseases. Efficacy was evaluated in 71 patients of monotherapy group and 70 patients of combination therapy group. Underlying diseases were mostly leukemia and lymphoma. Infections included sepsis, suspected sepsis, pneumonia and so on. Efficacy in CZOP monotherapy was excellent in 21 patients (31.3%), good in 23 patients (34.3%), fair in 5 patients (7.5%) and the efficacy rate was 65.7%. On the other hand, in combination therapy, each was 14 patients (21.2%), 23 patients (34.8%), 12 patients (18.2%) and the efficacy rate was 56.1%. Side effects such as eruption were noted in 2 patients. Abnormal laboratory findings were noted in 9 patients. All side effects as well as abnormal laboratory findings were minimal. It was concluded that CZOP monotherapy was effective in the treatment of various infections accompanying hematological diseases.

Exogenous insulin-like growth factor (IGF)-1 improves the impaired healing of gastric mucosal lesions in diabetic rats

BACKGROUND

We examined the influence of diabetes mellitus (DM) on the healing of HCl-induced gastric lesions and the healing promoting effect of IGF-1 on these lesions.

METHODS

Experiments were performed on rats injected with streptozotocin (STZ, 70 mg kg(-1), i.p.) 5 weeks prior to the experimental session. Diabetic animals had blood glucose levels (BGLs) higher than 350 mg dl(-1). Randomly chosen rats were treated with insulin (4 IU day(-1) rat(-1)) starting 1 week after STZ. Animals were given 1 ml of 0.6 m HCl by gavage following 18 h of fasting. Normal feeding was started 1 h later. Animals were killed at various time points after HCl. Recombinant human IGF-1 (rhIGF-1) at doses 10-400 microg kg(-1) was injected subcutaneously twice daily for 4 days following HCl treatment.

RESULTS

Gastric lesions induced by HCl healed macroscopically within 10 days. DM and insulin regimen did not affect the development of HCl-invoked gastric lesions. However, DM significantly delayed the healing of such lesions. Daily administration of insulin returned the high BGLs to significantly lower ranges (190-210 mg dl(-1)) and markedly antagonized the delayed healing. Likewise, the repeated administration of rhIGF-1 (>/=10 microg kg(-1)) significantly enhanced the healing of gastric lesions in diabetic rats, without any notable effect on BGLs or gastric acid secretion. The mucosal expression of IGF-1 mRNA was lower in diabetic rat stomachs as compared to normal rats, although the expression was apparently restored after insulin treatment.

CONCLUSION

These results suggest that DM has a deleterious influence on the healing of acute gastric lesions in both insulin- and IGF-1-sensitive manner. The systemic administration of rhIGF enhanced the rate of healing of gastric lesions observed in the healing-impaired STZ-diabetic animals.

Anchoring proteins confer G protein sensitivity to an inward-rectifier K(+) channel through the GK domain

Anchoring proteins cluster receptors and ion channels at postsynaptic membranes in the brain. They also act as scaffolds for intracellular signaling molecules including synGAP and NO synthase. Here we report a new function for intracellular anchoring proteins: the regulation of synaptic ion channel function. A neuronal G protein-gated inwardly rectifying K(+) channel, Kir3.2c, can not be activated either by M(2)-muscarinic receptor stimulation or by G(betagamma) overexpression. When coexpressed with SAP97, a member of the PSD/SAP anchoring protein family, the channel became sensitive to G protein stimulation. Although the C-terminus of Kir3. 2c bound to the second PDZ domain of SAP97, functional analyses revealed that the guanylate kinase (GK) domain of SAP97 is crucial for sensitization of the Kir3.2c channel to G protein stimulation. Furthermore, SAPAP1/GKAP, which binds specifically to the GK domain of membrane-associated guanylate kinases, prevented the SAP97-induced sensitization. The function of a synaptic ion channel can therefore be controlled by a network of various intracellular proteins.

Molecular aspects of ATP-sensitive K+ channels in the cardiovascular system and K+ channel openers

ATP-sensitive K+ (K(ATP)) channels are inhibited by intracellular ATP (ATPi) and activated by intracellular nucleoside diphosphates and thus, provide a link between cellular metabolism and excitability. K(ATP) channels are widely distributed in various tissues and may be associated with diverse cellular functions. In the heart, the K(ATP) channel appears to be activated during ischemic or hypoxic conditions, and may be responsible for the increase of K+ efflux and shortening of the action potential duration. Therefore, opening of this channel may result in cardioprotective, as well as proarrhythmic, effects. These channels are clearly heterogeneous. The cardiac K(ATP) channel is the prototype of K(ATP) channels possessing approximately 80 pS of single-channel conductance in the presence of approximately 150 mM extracellular K+ and opens spontaneously in the absence of ATPi. A vascular K(ATP) channel called a nucleoside diphosphate-dependent K+ (K(NDP)) channel exhibits properties significantly different from those of the cardiac K(ATP) channel. The K(NDP) channel has the single-channel conductance of approximately 30-40 pS in the presence of approximately 150 mM extracellular K+, is closed in the absence of ATPi, and requires intracellular nucleoside di- or triphosphates, including ATPi to open. Nevertheless, K(ATP) and K(NDP) channels are both activated by K+ channel openers, including pinacidil and nicorandil, and inhibited by sulfonylurea derivatives such as glibenclamide. It recently was found that the cardiac K(ATP) channel is composed of a sulfonylurea receptor (SUR)2A and a two-transmembrane-type K+ channel subunit Kir6.2, while the vascular K(NDP) channel may be the complex of SUR2B and Kir6.1. By precisely comparing the functional properties of the SUR2A/Kir6.2 and the SUR2B/Kir6.1 channels, we shall show that the single-channel characteristics and pharmacological properties of SUR/Kir6.0 channels are determined by Kir and SUR subunits, respectively, while responses to intracellular nucleotides are determined by both SUR and Kir subunits.

Gastric acid secretion in streptozotocin-diabetic rats--different responses to various secretagogues

We compared gastric acid secretion in response to various stimuli in normal and streptozotocin (STZ)-induced diabetic rats, in an attempt to characterize the alteration of acid secretory response in diabetic conditions. Animals were injected STZ (70 mg x kg(-1), i.p.) and used after 5 weeks of diabetes with blood glucose > 350 mg x dL(-1). Under urethane anesthesia, a rat stomach was mounted on an ex vivo chamber, perfused with saline and acid secretion was measured at pH 7.0 using a pH-stat method and by adding 100 mM NaOH. The acid secretion was stimulated by i.v. infusion of either histamine (4 mg x kg(-1) x h(-1)), pentagastrin (60 microg x kg(-1) x h(-1)) or carbachol (20 microg x kg(-1) x h(-1)) or i.v. injection of YM-14673 (0.3 mg x kg(-1)), an analog of thyrotropin-releasing hormone, or vagal electrical stimulation (2 ms, 3 Hz, 0.5 mA). In normal rats, gastric acid secretion was increased in response to either histamine, pentagastrin, carbachol, YM-14673 or electrical vagal stimulation. In STZ diabetic rats, however, changes in acid secretion varied depending on the stimuli; the acid secretory responses to histamine remained unchanged, those to YM-14673 and vagal electrical stimulation significantly decreased, but the responses to both pentagastrin and carbachol were significantly enhanced as compared to normal rats. Luminal release of histamine in response to both pentagastrin and carbachol was increased in STZ-diabetic rats as compared to normal animals. The altered acid secretory responses in STZ diabetic rats were partially reversed by daily injection of insulin with amelioration of high blood glucose levels. These results suggest that STZ-diabetic rats showed different changes in gastric acid secretory responses to various stimuli; no change in response to histamine, a decrease to both YM-14673 and vagal electrical stimulation and an increase to both pentagastrin and carbachol. The increased acid secretory response may be associated with an enhanced release of mucosal histamine, while the decreased response may be due to vagal neuropathy.

[Intrathoracic neurofibroma originating in the left vagus nerve]

A 20-year-old man was admitted because of an abnormal mass shadow on chest X-ray film. Computed tomography (CT) and magnetic resonance imaging (MRI) disclosed a mass lesion in the superior portion of the left mediastinum. CT scans showed a well-defined mass with low density. Axial MRI rendered the mass lesion with intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images. The preoperative diagnosis was bronchogenic cyst. Video-assisted thoracic surgery revealed that the tumor originated in the truncus of the left vagus nerve. The resected tumor was 90 x 24 x 18 mm in size. The postoperative course was uneventful and hoarseness did not develop. The pathologic diagnosis was benign mediastinal neurofibroma without von Recklinghausen's disease. Such cases are extremely rare in the Japanese literature.

Carotenoids and retinoids as suppressors on adipocyte differentiation via nuclear receptors

The adipocyte differentiation program is regulated by the sequential expression of transcriptional activators, mainly peroxisome proliferator activated receptor (PPAR) families. In the present study, we have decided to systematically examine the effects of vitamin A and its precursors, carotenoids and retinoids, on terminal differentiation from preadipocytes to adipocytes on the cellular and molecular aspects. The effects of active form of vitamin A, retinoic acid (RA), are believed to be mediated by specific nuclear receptor proteins [retinoic acid receptor (RAR)] which are members of the steroid and thyroid/retinoid receptor superfamily of ligand dependent transcriptional regulators, RARalpha, RARgamma, RXRalpha, and RXRbeta mRNA were abundant in adipose tissue and 3T3-L1 adipose cells. The autoregulated amplification of RARgamma mRNA was observed by these own ligands in 3T3-L1 cells. And, RA inhibited PPARgamma2 expression more effectively and caused concomitantly a greater inhibition of adipocyte differentiation. These results suggest that the inhibitory action of adipocyte differentiation by carotenoids and retinoids are exhibited through the RAR up-regulation and the suppression of PPARgamma2. The nature of the cross talk of vitamin A actions between the RARs, RXRs and PPARs via co-activator in adipose tissue will likely prove to be important for understanding the process of adipogenesis.

Ropporin, a sperm-specific binding protein of rhophilin, that is localized in the fibrous sheath of sperm flagella

The small GTPase Rho; functions as a molecular switch that regulates various cellular processes such as cell adhesion, motility, gene expression and cytokinesis. We previously isolated several putative Rho; targets including rhophilin which bound selectively to the GTP-bound form of Rho;. Rhophilin is expressed highly in testis and is localized specifically in sperm flagella. The presence of a PDZ domain at the carboxy terminus of rhophilin suggested that rhophilin works as an adaptor molecule. To test this hypothesis, we employed a yeast two hybrid system using the rhophilin PDZ domain as a bait, and screened a mouse testis cDNA library. We isolated several positive clones containing the same insert. The open reading frame of the cDNA encoded a novel protein of 212 amino acids designated as ropporin from a Japanese word ‘oppo’ (the tail). The amino-terminal 40 amino acid sequence of ropporin showed high homology to that of the regulatory subunit of type II cAMP-dependent protein kinase, which is involved in dimerization and binding to A-kinase anchoring proteins. Consistently, a yeast two hybrid assay and gel filtration of recombinant ropporin indicated that ropporin dimerizes through this domain. Deletion analysis indicated that the carboxy-terminal four amino acids are essential for binding of ropporin to rhophilin, and ropporin and RhoV14 coprecipitated in the presence of rhophilin in vitro. Northern blot analysis showed that ropporin is exclusively expressed in testis, and induced at the late stage of spermatogenesis. This induction paralleled that of rhophilin. Immunocytochemistry using anti-ropporin antibody showed that ropporin is localized in the principal piece and the end piece of sperm flagella. Electronmicroscopy revealed that ropporin is mostly localized in the inner surface of the fibrous sheath while rhophilin is present in the outer surface of the outer dense fiber. These results suggest that rhophilin and ropporin may form a complex in sperm flagella.

Molecular cloning and characterization of a novel splicing variant of the Kir3.2 subunit predominantly expressed in mouse testis

1. One of the features of weaver mutant mice is male infertility, which suggests that Kir3.2, a G-protein-gated inwardly rectifying K+ channel subunit, may be involved in spermatogenesis. Therefore, we have characterized the Kir3.2 isoform in mouse testis using immunological, molecular biological and electrophysiological techniques. 2. Testicular membrane contained a protein that was recognized by the antibody specific to the C-terminus of Kir3.2c (aG2C-3). Its molecular mass was approximately 45 kDa, which was smaller than that of Kir3.2c ( approximately 48 kDa). The immunoprecipitant obtained from testis with aG2C-3 contained a single band of the 45 kDa protein, which could not be detected by the antibody to the N-terminus common to the known Kir3.2 isoforms (aG2N-2). 3. A novel alternative splicing variant of Kir3.2, designated Kir3.2d, was isolated from a mouse testis cDNA library. The cDNA had an open reading frame encoding 407 amino acids, whose molecular mass was calculated to be approximately 45 kDa. Kir3.2d was 18 amino acids shorter than Kir3.2c at its N-terminal end, which was the only difference between the two clones. The 18 amino acid region possesses the epitope for aG2N-2. 4. In heterologous expression systems of both Xenopus oocytes and mammalian cells (HEK 293T), Kir3.2d either alone or with Kir3.1 exhibited G-protein-gated inwardly rectifying K+ channel activity. 5. Prominent Kir3.2d immunoreactivity in the testis was detected exclusively in the acrosomal vesicles of spermatids, while Kir3.1 immunoreactivity was diffuse in the spermatogonia and spermatocytes. These results indicate the possibility that the testicular variant of Kir3.2, Kir3. 2d, may assemble to form a homomultimeric G-protein-gated K+ channel and be involved in the development of the acrosome during spermiogenesis.

[Usefulness of tracheal tube with N2O gas-barrier cuff]

We evaluated three different tracheal tubes, Portex Profile Soft-Seal Cuff (PSSC), Portex Profile Cuff (PC) and Mallincrodt Lo-Contour (LC), when they are used in the artificial trachea and in anesthetized patients. When a cuff was inflated in the artificial trachea, PSSC with a cuff of high N2O gas-barrier property, and PC could achieve air-tight sealing with a smaller amount of injected air, compared with LC. This finding suggests that the inflated cuff-shape and cuff-fold formation are important to block the airway leakage with small volume of air. Either of three tubes was used randomly in thirty adult patients for general anesthesia using nitrous oxide 65%. Intracuff pressures were increased significantly with the passage of time. In PSSC group, however, intracuff pressure was 25 +/- 6 mmHg (mean +/- SD) at two hours, and in other two groups it was between 32 and 48 mmHg. The use of a tracheal tube with gas-barrier cuff is recommended to prevent a high tracheal wall pressure.

Expression of p16INK4A and p14ARF in hematological malignancies

The INK4A/ARF locus yields two tumor suppressors, p16INK4A and p14ARF, and is frequently deleted in human tumors. We studied their mRNA expressions in 41 hematopoietic cell lines and in 137 patients with hematological malignancies; we used a quantitative reverse transcription-PCR assay. Normal peripheral bloods, bone marrow and lymph nodes expressed little or undetectable p16INK4A and p14ARF mRNAs, which were readily detected in 12 and 17 of 41 cell lines, respectively. Patients with hematological malignancies frequently lacked p16INK4A expression (60/137) and lost p14ARF expression less frequently (19/137, 13.9%). Almost all patients without p14ARF expression lacked p16INK4A expression, which may correspond to deletions of the INK4A/ARF locus. Undetectable p16INK4A expression with p14ARF expression in 41 patients may correspond to p16INK4A promoter methylation or to normal expression status of the p16INK4A gene. All patients with follicular lymphoma (FL), myeloma or acute myeloid leukemia (AML) expressed p14ARF while nine of 23 patients with diffuse large B cell lymphoma (DLBCL) lost p14ARF expression. Patients with ALL, AML or blast crisis of chronic myelogenous leukemia expressed abundant p16INK4A mRNAs more frequently than patients with other diseases (12/33 vs 6/104, P < 0.01). Patients with FL and high p14ARF expression had a significantly shorter survival time while survival for patients with DLBCL and increased p14ARF expression tended to be longer. These observations indicate that p16INK4A and p14ARF expression is differentially affected among hemato- logical malignancies and that not only inactivation but also increased expression may have clinical significance.

[Levofloxacin concentrations in serum, sputum and lung tissue: evaluation of its efficacy according to breakpoint]

The levels of levofloxacin (LVFX) in the serum, sputum and lung tissue were measured by a high-performance liquid chromatography method, and the penetration ratio of LVFX into respiratory tissue was investigated. The subjects of this study were 23 patients under pulmonectomy or brochoscopy. LVFX at the dose of 200 mg was given orally and specimens were collected as follows; serum at 2, 3 and 5 hours after, sputum at 2 hours after, and lung tissue at 3 and 5 hours after the administration, respectively. The mean level of LVFX in lung tissue at 3 hours was 3.91 +/- 2.33 micrograms/g, and those in sputum and in serum at 2 hours were 0.71 +/- 0.63 and 2.08 +/- 1.01 micrograms/ml, respectively. A very strong correlation was demonstrated between the level of LVFX in lung tissue and that in serum (p < 0.0001), but correlation between those in sputum and in serum was not significant. The penetration ratio of LVFX into lung tissue was 217.2% and that into sputum was 4.05%. Based on the results of this study, the breakpoints (BPs) of LVFX for pneumonia and chronic respiratory tract infections were calculated to be 4 micrograms/ml and 1 microgram/ml, respectively. It was concluded that penetration of LVFX into lung tissue was satisfactory, and the tissue level of LVFX exceeded greatly the MIC90s against the typical pathogenic bacteria of respiratory tract infections. Taking the excellent BP for pneumonia, 4 micrograms/ml, into consideration, it was thought that LVFX is an effective antibacterial agent against pneumonia and other respiratory tract infections.

High-resolution immunogold cytochemistry indicates that AQP4 is concentrated along the basal membrane of parietal cell in rat stomach

Gastric parietal cells secrete hydrochloric acid in stomach. Because the secreted HCl solution is isotonic with the plasma fluid, it should accompany the water transport across the membranes of parietal cells. Aquaporins (AQPs) are water channel proteins that play the central role in the cellular handling of water in various mammalian tissues. Using immunocytochemistry, we found that AQP4 was expressed only in parietal cells of rat gastric mucosa. Immunogold electron microscopy study further demonstrated that AQP4 was mostly localized at the basal membrane of parietal cells. In the basal membrane, AQP4 was prominently enriched on the portion contacting with the basement membrane surrounding gastric glands. These results suggest that the contact between basement membrane and basal membrane may generate the signal involved in the targeting of AQP4 in gastric parietal cells.

Expression and polarized distribution of an inwardly rectifying K+ channel, Kir4.1, in rat retinal pigment epithelium

1. In the eye, different substances and ions including potassium (K+) are transported between neural retina and choroid via the subretinal space. Inwardly rectifying K+ channels (Kir) on the apical membrane of retinal pigment epithelial (RPE) cells are thought to play an essential role in K+ transport in the subretinal space. 2. Single-channel recordings from the apical membrane of RPE cells exhibited functional expression of a Kir channel with properties identical to those of Kir4.1, while recordings from the basolateral membrane showed no detectable Kir channel currents. 3. The expression of Kir4.1 mRNA in RPE cells was confirmed by RT-PCR analysis and in situ hybridization. Furthermore, using immunohistochemistry, we found that Kir4.1 was prominently expressed in RPE cells and localized specifically on the processes on their apical membrane. 4. Developmental studies revealed that expression of Kir4.1 started to appear 10 days or later after birth in RPE cells, in parallel with the maturation of retinal neuronal activity as represented by the a- and b-waves of the electroretinogram. 5. These data suggest that Kir4.1 is one of the Kir channels involved in RPE-mediated control of K+ ions in the subretinal space.

Expression of an inwardly rectifying K(+) channel, Kir4.1, in satellite cells of rat cochlear ganglia

Satellite cells are glial cells wrapped around somata of sensory and autonomic ganglion neurons. Neither their functional roles nor electrical properties have been fully clarified so far. Using immunohistochemistry, we found that inwardly rectifying K(+) channel subunit Kir4.1 (also called Kir1.2 or K(AB)-2) was expressed prominently in the satellite cells of cochlear ganglia. The Kir4.1 immunoreactivity was localized specifically at the myelin sheaths of satellite cells wrapping the somata of the ganglion neurons. Developmental expression of Kir4.1 in satellite cells paralleled development of the action potential in the auditory nerve. These results suggest that this channel in satellite cells may be responsible for the regulation of K(+) extruded from the ganglion neurons during excitation.

Effect of monochloramine on recovery of gastric mucosal integrity and blood flow response in rat stomachs--relations to capsaicin-sensitive sensory neurons

Gastric mucosal blood flow (GMBF) response and the recovery of gastric mucosal integrity were investigated in anesthetized rat stomachs after damage by monochloramine (NH2Cl), in comparison with 20 mM taurocholate Na (TC). A rat stomach was mounted in an ex-vivo chamber, and the mucosa was exposed to 50 mM HCl during a test period. Mucosal application of 20 mM TC for 10 min caused a marked reduction of transmucosal potential difference (PD), but the PD recovered rapidly without development of gross lesions 90 min later. In contrast, the exposure of the mucosa to NH2Cl (5 to approximately 20 mM) produced a concentration-dependent decrease in gastric PD, and the values remained lowered even 90 min after removal of the agent, resulting in severe hemorrhagic damage in the stomach. TC caused a considerable H+ back-diffusion, followed by an increase in the GMBF. In the mucosa damaged by NH2Cl, such GMBF responses were not observed, except for the temporal increase during the exposure, although similar degrees of H+ back-diffusion were observed following NH2Cl treatment. In addition, the prior exposure of the mucosa to NH2Cl significantly attenuated gastric hyperemic response induced by capsaicin but not by misoprostol (a PGE1 derivative) or NOR-3 (a NO donor). Chemical ablation of capsaicin-sensitive sensory neurons had no effect on the PD reduction caused by TC but totally attenuated the GMBF response, resulting in hemorrhagic damage in the stomach. These results suggest that NH2Cl delayed the recovery of the mucosal integrity in the stomach after damage, and this effect may be attributable, at least partly, to the impairment of gastric hyperemic response associated with H+ back-diffusion, probably due to dysfunction of capsaicin-sensitive sensory neurons.

Effect of lafutidine, a novel histamine H2-receptor antagonist, on monochloramine-induced gastric lesions in rats: role of capsaicin-sensitive sensory neurons

BACKGROUND

Lafutidine ((+/-)-2-(furfurylsulfinyl)-N-(4-(4-(piperidinomethyl)-2-pyr idyl)oxy-(Z)-2-butenyl)acetamide) is a novel histamine H2-receptor antagonist and has been shown to exhibit a potent gastroprotective activity in addition to its antisecretory action. In the present study, we examined the effects of lafutidine on the mucosal ulcerogenic and potential difference (PD) responses induced by monochloramine (NH2Cl) in rat stomachs.

METHODS

Oral administration of NH2Cl at 120 mmol/L produced haemorrhagic lesions in the stomach in unanaesthetized rats.

RESULTS

Lafutidine (3-30mg/kg), given p.o., showed a dose-dependent and significant inhibition against damage caused by NH2Cl: the effect was significant at 10 mg/kg or greater but disappeared almost totally in the sensory deafferented animals following capsaicin pretreatment. Likewise, capsaicin (10 mg/kg, p.o.), but not cimetidine (100 mg/kg, p.o.) exhibited a potent protection against NH2Cl-induced gastric lesions. Topical application of NH2Cl (10 mmol/L) reduced transmucosal PD in ex-vivo stomachs of anaesthetized rats, but this PD response was also prevented by pre-exposure to lafutidine, in a dose-dependent and sensory neuron-sensitive manner. Mucosal exposure to NH4OH (60 mmol/L) also caused PD reduction in ex-vivo stomachs made ischaemic by bleeding from the carotid artery (1 mL/100 g bodyweight), resulting in severe gastric lesions. These ulcerogenic and PD responses caused by NH4OH plus ischaemia were attenuated by prior application of lafutidine as well as taurine, a scavenger of NH2Cl. The former effect was, again, dependent on the sensory neurons. Intraluminal capsaicin but not cimetidine was also effective in preventing a PD response to NH2Cl.

CONCLUSIONS

These results suggest that lafutidine, but not cimetidine, protects the stomach against NH2Cl, whether occurring endogenously or administered exogenously and that this action may be mediated by capsaicin-sensitive sensory neurons.

Allergic bronchopulmonary aspergillosis due to Aspergillus niger without bronchial asthma

A 65-year-old woman was admitted to our hospital with a dry cough and pulmonary infiltrates. Chest radiograph and CT revealed mucoid impaction and consolidations. Peripheral blood eosinophilia and elevated serum IgE were observed. Aspergillus niger was cultured repeatedly from her sputum, but A. fumigatus was not detected. Immediate skin test and specific IgE (RAST) to Aspergillus antigen were positive. Precipitating antibodies were confirmed against A. niger antigen, but not against A. fumigatus antigen. She had no asthmatic symptoms, and showed no bronchial hyperreactivity to methacholine. Thus, this case was diagnosed as allergic bronchopulmonary aspergillosis (ABPA) without bronchial asthma due to A. niger, an organism rarely found in ABPA. The administration of prednisone improved the symptoms and corrected the abnormal laboratory findings.

Signaling from Rho to the actin cytoskeleton through protein kinases ROCK and LIM-kinase

The actin cytoskeleton undergoes extensive remodeling during cell morphogenesis and motility. The small guanosine triphosphatase Rho regulates such remodeling, but the underlying mechanisms of this regulation remain unclear. Cofilin exhibits actin-depolymerizing activity that is inhibited as a result of its phosphorylation by LIM-kinase. Cofilin was phosphorylated in N1E-115 neuroblastoma cells during lysophosphatidic acid-induced, Rho-mediated neurite retraction. This phosphorylation was sensitive to Y-27632, a specific inhibitor of the Rho-associated kinase ROCK. ROCK, which is a downstream effector of Rho, did not phosphorylate cofilin directly but phosphorylated LIM-kinase, which in turn was activated to phosphorylate cofilin. Overexpression of LIM-kinase in HeLa cells induced the formation of actin stress fibers in a Y-27632-sensitive manner. These results indicate that phosphorylation of LIM-kinase by ROCK and consequently increased phosphorylation of cofilin by LIM-kinase contribute to Rho-induced reorganization of the actin cytoskeleton.

Pineoblastoma showing unusual ventricular extension in a young adult--case report

A 19-year-old male presented with a 4-week history of headache. Neurological examination showed bilateral papilledema. Computed tomography revealed a pineal region mass with remarkable obstructive hydrocephalus. Magnetic resonance imaging showed a pineal region tumor continuously invading through the tectum into the cerebral aqueduct and the fourth ventricle with the preservation of the adjacent structures. The tumor appeared an iso- to hypointense mass on T1-weighted images, a heterogeneous iso- to hyperintense mass on T2-weighted images, and a heterogeneously enhanced mass after administration of contrast medium. Histological examination after endoscopic biopsy confirmed that the tumor was a pineoblastoma. Radiotherapy was given to the whole brain and the spinal cord, and magnetic resonance imaging showed complete remission of the tumor. Pineoblastomas are highly malignant tumors with seeding potential through the neighboring ventricle or along the meninges, and this type of tumor becomes larger with local extension. We found no previous reports of the continuous extension into the fourth ventricle. The present case showed ventricular extension with minimal mass effect to adjacent structures, and did not disturb ventricular configuration. According to the unusual finding of ventricular extension, this rare case of pineoblastoma requires adjuvant chemotherapy.