Influenza A virus infection increases IgE production and airway responsiveness in aerosolized antigen-exposed mice

BACKGROUND

Respiratory viral infection is known clinically to promote sensitization to antigen inhalation and the development of asthma.

OBJECTIVE

The purpose of this investigation was to determine whether influenza type A virus infection enhances inhalation sensitization and increases airway responsiveness in mice.

METHODS

Mice were infected by intranasal inoculation with influenza A viruses (strains: H1N1 and H3N2) or PBS. Animals were exposed to aerosols of ovalbumin on day 3. Two weeks after ovalbumin sensitization, mice were challenged with ovalbumin aerosols; 24 hours later, airway responsiveness (AR) to inhaled methacholine, levels of ovalbumin-specific IgE, and bronchoalveolar lavage fluid (BALF) were examined.

RESULTS

Neither influenza A virus (H1N1 nor H3N2) alone nor ovalbumin sensitization alone caused changes in AR or IgE. However, ovalbumin sensitization after inoculation with either influenza A virus increased AR and levels of ovalbumin-specific IgE. On BALF-cell analysis, ovalbumin sensitization after inoculation with influenza virus A increased the number of lymphocytes but not the number of eosinophils. No difference in AR or IgE levels was observed between the 2 strains of influenza A viruses. Immmunostaining of BALF cells showed an increase in T cells, especially CD8(+) cells, with ovalbumin sensitization after inoculation with influenza virus A.

CONCLUSION

Infection by influenza A virus enhances sensitization to inhaled antigens and airway responsiveness in mice by means of mechanisms including CD8(+) cells and antigen-specific IgE.

Shedding of the soluble IL-6 receptor is triggered by Ca2+ mobilization, while basal release is predominantly the product of differential mRNA splicing in THP-1 cells

The soluble IL-6 receptor (sIL-6R) is generated through either proteolytic shedding of the cognate receptor (PC-sIL-6R), or released as the product of differential mRNA splicing (DS-sIL-6R). Using monocytic THP-1 cells, we demonstrate that both mechanisms are independently regulated, and that each process contributes to sIL-6R production. Shedding of the IL-6R was activated by the Ca2+ ionophore, ionomycin, and inhibited by the TNF-alpha protease inhibitor (TAPI). In contrast, basal sIL-6R release was unaffected by Ca2+ depletion and largely insensitive to TAPI. Moreover, although IL-6R shedding was inactivated by serum starvation, non-stimulated production remained intact. Basal sIL-6R production via differential mRNA splicing was shown through the inhibitory action of brefeldin A and an enzyme-linked immunosorbent assay specific for DS-sIL-6R. Release of this isoform was unaffected by ionomycin or TAPI, indicating that Ca2+ mobilization activates PC-sIL-6R generation, but not DS-sIL-6R. The divergent control of these sIL-6R isoforms indicates that they may independently influence the inflammatory response.

High-level production of alternatively spliced soluble interleukin-6 receptor in serum of patients with adult T-cell leukaemia/HTLV-I-associated myelopathy

We have previously shown, using human T-cell lymphocytotrophic virus-I (HTLV-I)-infected cell lines, that soluble interleukin-6 receptor (sIL-6R) is generated through an alternative splicing mechanism. In this study, we examined human sera for the presence of alternatively spliced soluble IL-6R (AS-sIL-6R). We produced a monoclonal antibody (mAb) recognizing the unique sequence of AS-sIL-6R peptide, generated by an altered reading frame. We also made recombinant AS-sIL-6R protein in Spodoptera frugiperda-9 (Sf-9) cells carrying baculovirus, which encoded altered sIL-6R or conventional IL-6R cDNA. mAbs specifically recognized AS-sIL-6R, but not conventional IL-6R, as demonstrated by Western blot analyses, fluorescence-activated cell sorter, immunofluorescence analyses and enzyme-linked immunosorbent assay (ELISA). We adapted an ELISA system and used it for detection of altered sIL-6R in sera from 23 healthy persons, 12 patients with adult T-cell leukaemia (ATL) and 13 patients with HTLV-I-associated myelopathy (HAM). Serum levels of AS-sIL-6R were 6.4 or 6.1 times greater in ATL (28.7+/-20.4 ng/ml, P<0.0001) and in HAM patients (27.5+/-12.1 ng/ml, P<0.0001) than in healthy individuals (4.5+/-2.1 ng/ml). High levels of AS-sIL-6R were also observed in plasma from rheumatoid arthritis patients and in persons with elevated levels of alanine aminotransferase (ALT), antinuclear antibody (ANA), or alpha-fetoprotein (AFP). However, in human immunodeficiency virus-1 (HIV-1), hepatitis B virus (HBV) or hepatitis C virus (HCV)-infected individuals, AS-sIL-6R levels were not elevated. In this study, we confirmed that AS-sIL-6R is indeed present in human sera. These observations suggest that alternative splicing of IL-6R mRNA is of consequence in ATL, HAM and in some autoimmune diseases. The HTLV-I-infected T cells appeared to play an important role in AS-sIL-6R production.

In vitro characterization of rice importin beta1: molecular interaction with nuclear transport factors and mediation of nuclear protein import

We recently isolated two cDNAs encoding importin 3 homologues (rice importin beta1 and beta2), the first such homologues identified in plants. To address the function of rice importin beta1 in the process of nuclear import of proteins, we carried out in vitro binding and nuclear import assays. Recombinant protein of rice importin beta1 assembled a complex (PTAC) with rice importin alpha1 and NLS protein, and also bound to the nuclear envelope of tobacco BY-2 cells. Ran-GTP, but not Ran-GDP, interacted with rice importin beta1 and dissociated the heterodimer formed between rice importin alpha1 and rice importin beta1. An in vitro nuclear import assay using digitonin-permeabilized HeLa cells revealed that rice importin beta1 can mediate nuclear envelope docking of NLS proteins and their subsequent translocation into the nucleus. These data strongly suggest that rice importin beta1 functions as a component of the NLS receptor in plant cells.

A Gln747-->Pro substitution in the IIb subunit is responsible for a moderate IIbbeta3 deficiency in Glanzmann thrombasthenia

To clarify a molecular defect responsible for moderate alphaIIb beta3 deficiency, we examined two unrelated patients, MT and MS, suffering from type II and type I Glanzmann thrombasthenia (GT), respectively. Sequence analysis of polymerase chain reaction (PCR) fragments derived from platelet mRNA showed a single A-->C substitution at nucleotide (nt) 2334 leading to a Gln747--> Pro in alphaIIb in both patients. Allele-specific restriction enzyme analysis (ASRA) of genomic DNA demonstrated that patient MT was homozygous for the Gln747-->Pro substitution and patient MS was compound heterozygous for this substitution and for an RNA splice mutation at the consensus sequence of the splice acceptor site of exon 18 (AG-->AA). Furthermore, ASRA showed that, among 17 unrelated Japanese GT patients, this Gln747-->Pro substitution was detected in 4 patients, including MT and MS (homozygous, 2 patients; heterozygous, 2 patients). Cotransfection of Pro747alphaIIb and beta3 constructs into 293 cells resulted in moderate reduction in the amount of alphaIIb beta3 within the transfected cells as well as on the cell surface. However, Pro747alphaIIb beta3 bound the ligand mimetic monoclonal antibody (MoAb) PAC-1 after activation of alphaIIb beta3 by the MoAb PT25-2, suggesting that the mutant alphaIIb beta3 possesses the ligand-binding function. The association between the mutant proalphaIIb and beta3 was not disturbed. Surface labeling and pulse chase study showed that the Gln747-->Pro substitution moderately impaired both intracellular transport of the alphaIIb beta3 heterodimers to the Golgi apparatus and endoproteolytic cleavage of proalphaIIb into heavy and light chains. By contrast, replacement of Gln747 with Ala by mutagenesis did not impair alphaIIbbeta3 expression on the cell surface. These results suggest that the presence of Pro, rather than the absence of Gln, at amino acid residue 747 on alphaIIb is responsible for moderate alphaIIbbeta3 deficiency.

Coronary sinus pacing initiates counterclockwise atrial flutter while pacing from the low lateral right atrium initiates clockwise atrial flutter. Analysis of episodes of direct initiation of atrial flutter

INTRODUCTION

Rapid atrial pacing in sinus rhythm may directly induce atrial flutter without provoking intervening atrial fibrillation, or initiate atrial flutter indirectly, by a conversion from an episode of transient atrial fibrillation provoked by rapid atrial pacing. The present study was performed to examine whether or not the direct induction of clockwise or counterclockwise atrial flutter was pacing-site (right or left atrium) dependent.

METHODS AND RESULTS

We analyzed the mode of direct induction of atrial flutter by rapid atrial pacing. In 46 patients with a history of atrial flutter, rapid atrial pacing with 3 to 20 stimuli (cycle length = 500 - 170 ms) was performed in sinus rhythm to induce atrial flutter from 3 atrial sites, including the high right atrium, the low lateral right atrium, and the proximal coronary sinus, while recording multiple intracardiac electrograms of the atria. Direct induction of atrial flutter by rapid atrial pacing was a rare phenomenon and was documented only 22 times in 15 patients: 3, 11, and 8 times during stimulation, respectively, from the high right atrium, low lateral right atrium, and the proximal coronary sinus. Counterclockwise atrial flutter (12 times) was more frequently induced with stimulation from the proximal coronary sinus than from the low lateral right atrium (8 vs 1, P = .0001); clockwise atrial flutter (10 times) was induced exclusively from the low lateral right atrium (P = .0001 for low lateral right atrium vs proximal coronary sinus, P = .011 for low lateral right atrium vs high right atrium).

CONCLUSIONS

Direct induction of either counterclockwise or clockwise atrial flutter was definitively pacing-site dependent; low lateral right atrial pacing induced clockwise, while proximal coronary sinus pacing induced counterclockwise atrial flutter. Anatomic correlation between the flutter circuit and the atrial pacing site may play an important role in the inducibility of counterclockwise or clockwise atrial flutter.

Nine-year survivor after resection of cholangiocellular carcinoma with tumor thrombi in the main portal trunk

We report a patient with cholangiocellular carcinoma with tumor thrombi in the main portal trunk who has survived for 9.5 years after hepatic resection. A 57-year-old woman underwent an extended left lobectomy, and resection of the caudate lobe plus the main portal trunk for a liver tumor that had a portal tumor thrombus in the main portal trunk. The portal vein was reconstructed with an autologous vein graft obtained from the external iliac vein. Histological examination of the resected specimen revealed moderately differentiated tubular adenocarcinoma compatible with cholangiocellular carcinoma. Factors contributing to the patient's long-term survival are discussed. Aggressive surgical resection can be effective even for such an advanced case of cholangiocellular carcinoma.

Binding of HIV-2 envelope glycoprotein to CD8 molecules and related chemokine production

We recently found that human immunodeficiency virus (HIV)-2 envelope glycoprotein, but not that of HIV-1, could bind to CD4 and CD8 molecules on T cells, and that the binding site of HIV-2 envelope glycoprotein was located on the alpha-chain (but not the beta-chain) of CD8. This study showed that the binding of HIV-2 envelope glycoprotein could induce phosphorylation of protein tyrosine kinase p56lck in CD8+ T cells. We also found that production of beta-chemokines in response to HIV-2 envelope glycoprotein was significantly higher than that in response to HIV-1 envelope glycoprotein, and that CD8+ T cells were the main source of beta-chemokines production among the T-cell population. These findings indicate the possibility that the binding of envelope glycoprotein to CD8 molecules are related to signal transduction into CD8+ T cells and the resultant beta-chemokine production in HIV-2 infection. Our results may help to explain the differences in disease manifestations between HIV-1 and HIV-2, including the lower virulence of HIV-2 and the longer survival of HIV-2-infected individuals.

Balance of activities of alcohol acetyltransferase and esterase in Saccharomyces cerevisiae is important for production of isoamyl acetate

Isoamyl acetate is synthesized from isoamyl alcohol and acetyl coenzyme A by alcohol acetyltransferase (AATFase) in Saccharomyces cerevisiae and is hydrolyzed by esterases at the same time. We hypothesized that the balance of both enzyme activities was important for optimum production of isoamyl acetate in sake brewing. To test this hypothesis, we constructed yeast strains with different numbers of copies of the AATFase gene (ATF1) and the isoamyl acetate-hydrolyzing esterase gene (IAH1) and used these strains in small-scale sake brewing. Fermentation profiles as well as components of the resulting sake were largely alike; however, the amount of isoamyl acetate in the sake increased with an increasing ratio of AATFase/Iah1p esterase activity. Therefore, we conclude that the balance of these two enzyme activities is important for isoamyl acetate accumulation in sake mash.

Effects of single and concurrent intermittent administration of human PTH (1-34) and incadronate on cancellous and cortical bone of femoral neck in ovariectomized rats

The purpose of this study is to determine the efficacy of concurrent treatment with human parathyroid hormone, hPTH (1-34), and bisphosphonate (incadronate) in augmenting cortical and cancellous bone mass of femoral neck in ovariectomized (OVX) rats. Forty-eight 11-week-old female Sprague-Dawley rats were divided into eight groups (six animals in each group). The baseline control group was killed at the beginning of the experiment, at 11 weeks of age. An ovariectomy was performed in thirty rats and twelve rats were subjected to a sham surgery. OVX rats were untreated for the first four weeks of postsurgery to allow for the development of moderate osteopenia. These animals were then subjected to various treatments with either PTH, incadronate, or PTH+ incadronate for a period of 4 weeks. Right proximal femora (femoral necks) were used for bone histomorphometry. After OVX 8 weeks, there was a significant decrease in cancellous bone mass and cortical bone area of femoral neck in the OVX rats when compared to the sham control rats. In OVX rats treated with PTH alone or PTH+ incadronate were completely restored lost cancellous and cortical bone mass of femoral neck by increase bone formation. The bone formation parameters (OS/ BS, MS/BS) and bone turnover (BFR/BV) seen with PTH plus incadronate were similar to those seen with PTH treatment alone. This indicates that incadronate did not blunt the anabolic action of PTH when used concurrently. Our results suggest the followings: 1) the femoral neck of OVX rats is a suitable sample site for preclinical studies of the prevention of bone loss induced by estrogen depletion; 2) concurrent use of incadronate did not blunt the anabolic effect of PTH; 3) concurrent treatment showed the best results in restoring cancellous and cortical bone mass; and 4) it had additional benefits for bone strength independent of that achieved by the increase in bone mass.

Functional characterization of a plant importin alpha homologue. Nuclear localization signal (NLS)-selective binding and mediation of nuclear import of nls proteins in vitro

Nuclear import of most nuclear proteins is initiated by recognition of the nuclear localization signal (NLS) by importin alpha. We recently isolated an importin alpha homologue from rice (rice importin alpha1) and demonstrated that transcription of the gene is down-regulated by light in rice leaves. To address the function of rice importin alpha1 in the process of nuclear import of proteins, we performed in vitro binding and nuclear import assays. The rice importin alpha1 showed specific binding to fusion proteins containing either monopartite or bipartite NLSs, but not to a fusion protein containing a Matalpha-2-type NLS, suggesting that there exists selective binding of rice importin alpha1 to different plant NLSs. The rice importin alpha1 is also capable of forming a complex with mouse importin beta and NLS protein in vitro. An in vitro nuclear import assay using permeabilized HeLa cells revealed that rice importin alpha1, in conjunction with other vertebrate transport factors, mediates the nuclear envelope docking of NLS proteins and their subsequent translocation into the nucleus. These data provide strong, direct evidence suggesting that rice importin alpha1 functions as a component of the NLS receptor in plant cells.

Service use by family caregivers in Japan

This paper presents a conceptual framework for understanding how Japanese family caregivers make decisions about the use of formal services such as adult day care, short term hospital stays, and long-term institutionalization. Using grounded theory methodology, 26 Japanese daughters or daughters-in-law who were caring for an elderly demented parent or parent-in-law were interviewed. From these data, an overall process of "navigating among endorsed options" evolved. This process was set in motion when caregivers reached the limit of their tolerance, a point at which they felt they could not continue caregiving under the given arrangement. Caregivers then began to assess three issues which determined whether or not they used formal services: the availability of services; their authority level within the family; and whether or not they could justify their tolerance limit. The availability of a service was determined by the quality of the service, the distance to the service, the sanctions that would incur as a result of using the service, information about the service, and the quantity of the service. The caregivers' authority within the family varied depending on such factors as how much the caregiver was accepted by her married family or the type of family business. This authority level determined whether and how the caregivers could approach other family members in order to obtain their consent to use formal services. Finally, whether the caregivers could justify their tolerance limit depended on the internalization of the societal norm regarding family caregiving, attachment to the care recipient, and the caregiver's belief on how care should be given. Justification of their limit included re-prioritizing the needs of family members, acting in defiance of societal norm, and redefining reality. Each of the three issues was assessed in relation to the others with the final decision to use or not use formal services based on the balance of forces.

Human T-cell leukemia virus type I Tax transactivates human interleukin 8 gene through acting concurrently on AP-1 and nuclear factor-kappaB-like sites

The transactivator protein, Tax, from the human T-cell leukemia virus type I (HTLV-I) transactivates both viral and cellular genes. Previously, we had shown that interleukin 8 (IL-8) is constitutively expressed in HTLV-I-infected cells and in cells transiently expressing Tax. We show here that the IL-8 promoter is Tax responsive in Jurkat T cells. Furthermore, using several deletion and mutated plasmids of the 5'-flanking regulatory region of the IL-8 gene linked to the luciferase gene as a reporter and mutant tax gene expression vectors, we have established that both AP-1 at -126 to -120 and nuclear factor (NF)-kappaB-like cis-element at -80 to -71 are essential and sufficient for the induction of the IL-8 gene by HTLV-I Tax. In addition, overexpression of the dominant-negative mutants of NF-kappaB inhibitor molecules, IkappaBalpha and IkappaBbeta, abolished the Tax-induced activation of IL-8 gene. Gel mobility shift assays detected proteins specifically binding to the AP-1 and NF-kappaB-like sites in Tax-expressing T-cell lines infected with HTLV-I. Similarly, the nuclear translocation of proteins specifically bound to these two motifs was shown in JPX-9 cells, a subclone of Jurkat cells, carrying the Tax sequences under the control of an inducible promoter. Taken together, these results suggest that the cooperation of transcription factors NF-kappaB and AP-1 is essential for transactivation of IL-8 gene by HTLV-I Tax.

Caffeine-potentiated chemotherapy and conservative surgery for high-grade soft-tissue sarcoma

We report here the results of preoperative and postoperative caffeine-potentiated chemotherapy and limb-sparing surgery for soft-tissue sarcomas. Thirty-six patients with histologically high-grade soft-tissue sarcomas were treated with caffeine-potentiated chemotherapy and conservative surgery (25 cases of limb-sparing surgery and 11 of local tumor excision). There were 13 patients with malignant fibrous histiocytoma (MFH), eight with synovial sarcoma, five with liposarcoma, four with malignant schwannoma, four with epithelioid sarcoma, one with leiomyosarcoma and one with extraskeletal chondrosarcoma. Nine patients were at stage III with lung metastasis and the other 27 at stage IIB without metastasis; 22 were male and 14 female with a mean age of 48 years, ranging from 16 to 77. For intra-arterial preoperative chemotherapy, we administered 2-5 courses of cisplatin (120 mg/m2), doxorubicin (30 mg/m2 x 2 days), and caffeine (1.5 g/m2 x 3 days) to 18 patients, and cisplatin and caffeine to the other 18. Although 15 patients had already undergone unplanned tumor excision at other hospitals before preoperative chemotherapy, all patients underwent definitive limb-sparing surgery after the preoperative chemotherapy. Surgical margins were wide for 28 patients, marginal for three and intralesional for five. Local tumor recurrence was seen in one patient with MFH and one with epithelioid sarcoma. Of the 27 stage IIB patients, lung metastasis newly developed in one with MFH, three with synovial sarcoma, two with malignant schwannoma and one with leiomyosarcoma. As for the effects of preoperative chemotherapy in the 33 eligible cases, radiographically confirmed complete response was seen in two patients, partial response in 20 and no response in 11. Histological response to this preoperative chemotherapy consisted of grade I (no response) in 14, grade II (50-90% necrosis) in four, grade III (> 90% necrosis) in eight, and grade IV (no viable cells) in seven cases. An overall objective response rate of 73% was obtained. With the mean follow-up period of 58 months (5-101 months), the overall 5-year cumulative survival rate ascertained with the Kaplan-Meier method was 63% and that of stage II patients 81%. Eight of the nine stage III patients died of metastatic disease within two and a half years from the beginning of the treatment. In conclusion, caffeine-potentiated chemotherapy and limb-sparing surgery brought good results for stage II nonmetastatic soft-tissue sarcomas. The problem of treatment for stage III metastatic soft-tissue sarcomas, however, remains unsolved.

Nonfluoroscopic guidance for catheter placement into the coronary sinus under direct vision using a balloon-tipped cardioscope

The right atrial posterior septum, including the coronary sinus (CS) ostium, is an important landmark in radiofrequency catheter ablation therapy for supraventricular tachycardia or atrial flutter. The anatomical findings around the CS ostium would be useful to determine a target site or line during catheter ablation. The aim of the study was to test the ability of the imaging catheter to identify structures in the posterior septal area of the right atrium and to evaluate the feasibility of guidance for catheter placement in the CS using a cardioscope that we recently developed. In 12 anesthetized dogs, the cardioscope, consisting of a deflectable 7 Fr fiberoptic endoscope with an inflatable and transparent balloon, was introduced into the right atrium via the femoral vein. The cardioscope was manipulated to observe the right atrial posterior septum. A deflectable electrode catheter was inserted via the jugular vein and positioned in the CS under cardioscopic guidance. In 10 of 12 dogs, the right atrial posterior septum, including the CS ostium, and the tendon of Todaro could be anatomically identified by cardioscopy. It was possible to position an electrode catheter in the CS in all 10 dogs under direct vision without fluoroscopy. But the CS ostium could not be detected in the remaining two dogs, although the cardioscope was placed at as many sites as possible. No complication occurred. The balloon-tipped cardioscope appears to be useful in observing the right atrialposterior septum and in guiding an electrode catheter into the CS.

Effects of eicosapentaenoic acid and its 15-hydroperoxy and 15-hydroxy derivatives on glucosamine synthetase activity in rabbit gastric mucosa

The effects of eicosapentaenoic acid and its 15-hydroperoxy and 15-hydroxy adducts on the activity of glucosamine synthetase, the rate-limiting enzyme of mucus synthesis, in rabbit gastric antral mucosa were examined. 15-Hydroperoxy-eicosapentaenoic acid inhibited the glucosamine synthetase activity at concentrations of 10, 20 and 50 microM. The effect was concentration-dependent, and the concentration required for 50% inhibition was approximately 20 microM. Eicosapentaenoic acid and its 15-hydroxy adduct had no significant effect on the enzyme activity at the same concentration range. The experiment utilizing Fe2+ revealed that the inhibitory effect of 15-hydroperoxyeicosapentaenoic acid on the glucosamine synthetase activity is not due to hydroxy radical which is expected to be formed from the hydroperoxy adduct. These results suggest that 15-hydroperoxyeicosapentaenoic acid has the potential to reduce the synthesis of gastric mucus by inhibiting the glucosamine synthetase activity.

Induction of apoptosis in human tumour xenografts after oral administration of uracil and tegafur to nude mice bearing tumours

Various types of anti-neoplastic agents induce apoptosis in vitro, but less is known of the role of this mode of cell death in tumours treated in vivo. We examined the induction of apoptosis by oral anti-neoplastic agents, tegafur and uracil (UFT, a combined preparation of 1 mol tegafur and 4 mol uracil), and the relationship of effects on tumour growth. Seven different human gastrointestinal tumour xenografts were transplanted into nude mice, including two colon adenocarcinomas (KM20C and Col-1), three gastric carcinomas (SC-6, St-40 and 4-1ST) and two pancreatic carcinomas (PAN-4 and PAN-12), followed by oral administration of UFT (24 mg kg(-1) day(-1)) for 9 days. The percentage of apoptotic cells in each tumour was scored in histological sections, chronologically, using a molecular biological-histochemical system and growth inhibition was examined in each tumour. A significant growth inhibition by UFT was observed for all tumours, except PAN-12. In KM20C and SC-6, growth inhibition rates were 61.7% and 60.6% respectively. Quantitative assay for apoptosis showed a remarkable induction of apoptosis in KM20C (4.2%) and SC-6 (3.5%), which were relatively sensitive to UFT. In addition, KM20C and SC-6 showed a higher incidence of spontaneous apoptosis. In five other tumours, which responded to a lesser extent than KM20C and SC-6, UFT altered little the changes in apoptosis (less than 2%) and spontaneous apoptosis was relatively low. Thus, tumours with a higher apoptosis induced by UFT had a higher response to UFT. Apoptosis observed in tumours might serve as a predictor of a preferable response to UFT.

[Proliferation of corneal epithelial cells in diabetic rats]

In order to elucidate the mechanisms of diabetic corneal epitheliopathy, we investigated the proliferation of corneal epithelial cells of streptozotocin-induced diabetic rats in the 1st, 2nd, 3rd and 6th months after the onset of diabetes using 3H-thymidine autoradiography. After the 1st month in diabetic rats, histological examination revealed that corneal epithelial layer was thin, and proliferation of corneal epithelial cells was decreased compared with that of normal untreated rats. After the 2nd month, proliferation of corneal epithelial cells showed no difference from normal rats. After the 3rd month in diabetic rats, the attachment of the epithelial layer to the stroma was loose and proliferation of corneal epithelial cells was increased compared with that of normal untreated rats. After the 6th month, proliferation of corneal epithelial cells showed no difference between diabetic rats and normal rats. We suggest that increased turnover rate of corneal epithelial cells may account for increased proliferation of corneal epithelial cells in diabetic rats during the 3rd month.

Evolutionary origin of two genes for chloroplast small heat shock protein of tobacco

Two different cDNA clones for the chloroplast small heat shock protein (smHSP) were isolated from tobacco (Nicotiana tabacum cv. Petit Havana SR1). One of the cDNAs (type I) has a full-length open reading frame (ORF) of the smHSP of 26.6 kDa. By contrast, the other one (type II) contains an additional nucleotide that causes the frame shift inside a putative ORF for the smHSP. If this nucleotide is neglected, type II cDNA encodes the smHSP that is 89% identical to that encoded by type I cDNA. Southern blot and polymerase chain reaction (PCR) analyses with genomic DNA indicated that tobacco has two different smHSP genes while two ancestors of tobacco, N. sylvestris and N. tomentosiformis, have a single gene that each corresponds to one of the two genes of tobacco. It was also found that one of the tobacco genes has an ORF for the smHSP disrupted by nucleotide insertion in the same way as type II cDNA, while both ancestor genes have a functional ORF. These results suggest that the two smHSP genes of tobacco had been derived from the two ancestor species, and that one of the two genes had been disrupted by nucleotide insertion during the course of the evolution of tobacco. Northern blot and reverse transcription (RT)-PCR analyses demonstrated that both the tobacco genes are expressed upon heat stress, exhibiting different dependences on temperature.

Isolation and characterization of two importin-beta genes from rice

The nuclear transport of proteins is mediated by the complex of importin-alpha and importin-beta. We isolated two cDNAs encoding importin-beta from rice. A rice importin-beta was demonstrated to interact with rice GST-importin-alpha fusion proteins. The presence of two importin-beta genes was shown for the first time among a variety of eukaryotes.