Improved light extraction efficiency of InGaN-based multi-quantum well light emitting diodes by using a single die growth.

We have demonstrated that the light extraction efficiency of the InGaN based multi-quantum well light-emitting diodes (LEDs) can be improved by using a single die growth (SDG) method. The SDG was performed by patterning the n-GaN and sapphire substrate with a size of single chip (600 x 250 microm2) by using a laser scriber, followed by the regrowth of the n-GaN and LED structures on the laser patterned n-GaN. We fabricated lateral LED chips having the SDG structures (SDG-LEDs), in which the thickness of the regrown n-GaN was varied from 2 to 6 microm. For comparison, we also fabricated conventional LED chips without the SDG structures. The SDG-LEDs showed lower operating voltage when compared to the conventional LEDs. In addition, the output power of the SDG-LEDs was significantly higher than that of the conventional LEDs. From optical ray tracing simulations, the increase in the thickness and sidewall angle of the regrown n-GaN and LED structures may enhance photon escapes from the tilted facets of the regrown n-GaN, followed by the increase in light output power and extraction efficiency of the SDG-LEDs.

Total occlusion of left main coronary artery by dilated main pulmonary artery in a patient with severe pulmonary hypertension.

A 34-year-old woman was admitted to the hospital because of recently aggravated right heart failure without angina for 5 months. When she was 25 years old, patch repair with Polytetrafluoroethylene (PTFE) was performed for the secondum type of atrial septal defect (ASD) with moderate pulmonary hypertension. The chest PA, echocardiography and cardiac catheterization at current admission revealed Eisenmenger syndrome without intracardiac shunt. Chest CT scan with contrast revealed markedly dilated pulmonary trunk, both pulmonary arteries and concave disfigurement of the left side of the ascending aorta suggesting extrinsic compression, as well as total occlusion of the ostium of the left main coronary artery that was retrogradly filled with collateral circulation from the right coronary artery. The coronary angiography showed normal right coronary artery and the collaterals that come out from the conus branch to the mid-left anterior descending artery (LAD) and that from distal right coronary artery to the left circumflex artery (LCX) and to the distal LAD, respectively. On aortography, the left main coronary artery was not visualized with no stump, suggestive of total occlusion of the ostium of the left main coronary artery. From our experience, it is possible to say that the occlusion of the ostium of the left main coronary can be induced by the dilated pulmonary artery trunk due to ASD with pulmonary hypertension and that, if the ASD closure was too late, the narrowing or obstruction of the left coronary artery could not be resolved even after operation owing to irreversible pulmonary hypertension.

Inflammatory pseudotumor of urinary bladder.

A previously healthy 44-year-old male was admitted with the chief complaint of intermittent gross hematuria. On initial ultrasonographic and CT examination, a grossly protruding intravesical tumor was noted and, under the impression of a malignant bladder tumor, transurethral resection was performed. The histological findings were spindle cells with elongated cytoplasm with rare mitotic figures distributed in myxoid stroma, consistent with diagnosis of inflammatory pseudotumor of the bladder. The benign nature of this tumor warrants conservative surgical management, usually consisting of transurethral resection or partial cystectomy. No reports of metastasis have been reported following complete excision. Therefore, any suspicion and recognition of this entity is imperative to avoid performing an irreversible radical procedure.

Mixed hepatoblastoma in an adult--a case report and literature review.

Hepatoblastoma is thought to originate from embryonal hepatic tissue, and most of these tumors occur in children under the age of 2 years. Hepatoblastoma in adults is extremely rare, and the prognosis is much worse than the mixed hepatoblastoma of childhood. We experienced a case of mixed hepatoblastoma in a 51 year old female patient. She had been suffering from a mild pain and a palpable lump in the epigastric area. Serum AFP was 43,850 ng/ml. Computerized tomography and selective abdominal angiography showed a large low-density mass. With a suspicion of hepatocellular carcinoma of the left lobe, a left lateral segmentectomy was performed. The external surface showed a huge protruding mass and the capsule was previously ruptured. On section, the tumor was a 11 x 7 cm sized expanding mass which had a variegated surface composed of yellow-white friable tissue with multifocal hemorrhagic areas. Microscopic examination revealed a tumor consisted of epithelial and mesenchymal elements. The mesenchymal cells were spindle in shape and proliferated over the whole tumor with focal osteosarcomatous differentiation. The epithelial components showed well-differentiated hepatocellular carcinoma-like areas, poorly differentiated acinar or tubular structures.

Photoinactivation of virus infectivity by hypocrellin A.

We investigated the photoinactivation of virus infectivity by hypocrellin A and its mechanism. The titers of vesicular stomatitis virus (VSV) and human immunodeficiency virus type 1 (HIV-1), both of which are enveloped viruses, were reduced upon illumination with hypocrellin A in a concentration-dependent manner, whereas canine parvovirus, a nonenveloped virus, was not killed. The removal of oxygen or addition of sodium azide or beta-carotene both inhibited VSV inactivation. Mannitol and superoxide dismutase had no effect on VSV inactivation. These results indicate that singlet oxygen was involved in the process of VSV inactivation. Of the three major VSV membrane proteins, peripheral membrane protein M was most damaged by the hypocrellin A phototreatment.

Growth-blocking peptide titer during larval development of parasitized and cold-stressed armyworm.

Growth-blocking peptide (GBP) has been isolated for the first time from the haemolymph of the host armyworm Pseudaletia separata whose development was halted in the last larval instar stage by parasitization with the parasitoid wasp Cotesia kariyai. Recent studies demonstrated that GBP not only exists in the plasma (haemolymph without cells) of parasitized last instar larvae, but also in the plasma of nonparasitized penultimate (5th) instar larvae. Monoclonal antibodies were prepared to measure the titers of GBP in nonparasitized and parasitized larval plasma. One of three monoclonal antibodies raised against GBP, which is the most specific for GBP, was used to quantify the concentration of plasma GBP. As this antibody recognized two plasma peptides other than GBP in crude plasma fractions, each plasma peptide fraction was separated by a reversed phase HPLC, and then plasma GBP level was measured by ELISA. The highest level of plasma GBP detected on Day 0 of the penultimate instar larvae was gradually decreased throughout the larval growth except for the temporary increase on Day 0 of last larval instar. After parasitization on Day 0 of last larval instar, two peaks of plasma GBP titer were detected during the last larval instar, one day and six days after parasitization. This characteristic increase and decrease in plasma GBP level was also observed by transferring last instar larvae of the armyworm from 25 to 10 degrees C, as a result of which larvae delayed pupation by more than 15 days. From these results, it is reasonable to propose that plasma GBP in lepidopteran larvae might control certain upstream steps in a cascade of events leading to pupation; thus, an elevated level of plasma GBP interferes with normal metamorphosis from larvae to pupae.

[Epstein-Barr virus-specific immunity in asymptomatic carriers of human T-cell leukemia virus type 1].

Adult T-cell leukemia (ATL) patients are immunosuppressed as evidenced by anergy to recall antigens and the occurrence of opportunistic infections. The immunosuppression appears to be a critical factor or a predictive sign for the development of ATL in carriers of human T-cell leukemia virus type 1 (HTLV-1). This study was aimed at assessing the immune status of asymptomatic HTLV-1 carriers with the immunity specific to Epstein-Barr virus (EBV), a ubiquitous human herpesvirus with oncogenic potential. Forty-three asymptomatic HTLV-I carriers were examined for their EBV serology and EBV-specific cytotoxic T-cell (EBV-CTL) activity, in comparison with 10 HTLV-I-non-infected normal controls. Both carriers and controls were all positive for EBV capsid antigen (VCA) IgG. Significantly elevated titer of VCAIgG and lower titer of EBV-determined nuclear antigen (EBNA) antibodies were observed in asymptomatic HTLV-I carriers, suggesting reactivation of EBV. Among the HTLV-I carriers, 9 (20.9%) had reduced activity of EBV-CTL as revealed by lower incidence of regression of in vitro EBV-induced B-cell transformation. Accordingly, asymptomatic HTLV-I carriers were divided into three groups: the carriers with reduced EBV-specific cellular immunity (group I), the carriers showing normal cellular immunity but aberrant EBV-specific antibody titers (group II), and the carriers with normal EBV-specific cellular immunity and serology (group III). Higher positive rate of anti-HTLV-I Tax antibody was found in the former two groups (44.4% and 56.5%, respectively) compared with group III (18.2%). An immunosuppressive agent, 4-deoxyphorbol ester induced a remarkable decrease of EBV-CTL activity in the carriers of group II and III at the concentration that affected none of the normal controls. These findings indicate that asymptomatic HTLV-I carriers suffer stepwise impairment of EBV-specific immunities, which may be caused by HTLV-I infection.

Human cytomegalovirus DNA is not detectable with nested double polymerase chain reaction in healthy blood donors.

The PCR method was introduced to detect cytomegalovirus (CMV) DNA from 189 peripheral blood samples of volunteer donors. We adopted the nested double PCR method with primers specific for immediate early gene 1 followed by electrophoresis and ethidium bromide staining. This nested double PCR method was sensitive enough to detect approximately a single copy of CMV DNA. However, we failed to obtain positive amplification of CMV DNA from any of these donor samples. In contrast, CMV DNA could be detected in all 3 tested immunocompromised patients who had undergone bone marrow transplantation. These results support our previous report that the frequency of CMV DNA is of an order lower than 1 copy/10(5) leucocytes in the peripheral blood of healthy seropositive individuals.

Prevalence of human T-cell leukemia virus type 1 (HTLV-I) in general inhabitants in non-adult T-cell leukemia (ATL)-endemic Hokkaido, Japan.

In contrast to adult T-cell leukemia (ATL)-endemic southwestern Japan, the northernmost island Hokkaido has a small number of ATL patients annually. In this study, we surveyed 32,587 healthy inhabitants throughout Hokkaido for antibodies to human T-cell leukemia virus type 1 (HTLV-I). Only 244 individuals (0.8%) were seropositive as HTLV-I carriers; 0.6% (123 of 19,512) in males and 0.9% (121 of 13,075) in females. In some areas, however, the inhabitants had relatively high seropositivity (> 2%). The highest rate was 5.2% with a cluster of ATL patients in a certain town of the Hidaka area near the Pacific Ocean, in southeast Hokkaido.

A human monoclonal antibody to high-frequency red cell antigen Jra.

A human-mouse heterohybridoma (HMR0921) secreting human monoclonal IgG3, lambda antibody was produced from peripheral blood lymphocytes of a healthy blood donor with serum antibody to Jra, by EBV transformation and hybridization with mouse myeloma cell line P3X63Ag8.653. The reactivity of HMR0921 antibody was assessed by antiglobulin test with a panel of red cells including 14 different rare blood types. Only Jr(a-) red cells were negative. The strict specificity of this antibody to Jra antigen was further confirmed by absorption test with fluorescence flow cytometry. On screening of 28,744 blood donor samples by HMR0921 antibody, we detected 19 agglutination-negative samples, which were confirmed as Jr(a-) by conventional anti-Jra antisera. Therefore, our HMR0921 antibody is extremely useful for detecting rare Jr(a-) blood.

Oligo-2',5'-adenylate synthetase activity in cells persistently infected with human T-lymphotropic virus type I (HTLV-I).

Spontaneous production of interferon-gamma (IFN-gamma) was shown in several T-lymphoblastoid cell lines persistently infected with human T-lymphotropic virus (HTLV-1). However, the produced IFN-gamma was not always associated with the induction of the antivirus state. The induction of oligo-2',5'-adenylate synthetase (2-5AS) by IFN was studied in five human T-cell lines persistently infected with HTLV-I (MT-1, MT-2, SMT-1, HUT 102 and OKM-2). Four cell lines are able to produce IFN-gamma spontaneously, while the OKM-2 cell line is not. Poor induction of 2-5AS was recognized in three (MT-1, MT-2 and SMT-1) of the four cell lines producing IFN-gamma, though the poor induction was improved after long-term cultivation of cells with IFN-alpha. On the contrary, in the OKM-2 cell line, significant activity of the enzyme was induced by IFN-alpha. Induction of 2-5AS was not correlated with cell growth inhibition, but with the antivirus state. Furthermore, an inverse relationship between IFN-gamma production and 2-5AS induction was demonstrated in these cell lines with the exception of HUT 102 cells.

Evaluation of the human T-cell leukemia virus type I seropositivity of blood donors by the particle agglutination inhibition test.

In the HTLV-I seroscreening of blood donor sera by gelatin particle agglutination (PA), more than 50% (55.6%) of the PA-positive sera were negative by immunofluorescence assay (IF). However, when donors were divided into age groups, there were increasing numbers of IF-positive/PA-positive donors with age. Among the PA-positive donors in the 50-64 age group, 65.9% were IF-positive compared to 16.0% in the 16-19 age group. The serological specificities of the IF-negative/PA-positive specimens were tested by using a newly developed PA inhibition (PAI) test. The HTLV-I specificity of the PAI test was confirmed by the observation that agglutinations with anti-HTLV-I p19 and gp21 monoclonal antibodies as well as IF-positive sera were specifically inhibited with HTLV-I preparations or HTLV-I-positive cell extracts and not with HTLV-I-negative cell extracts. Sixty of the 104 specimens collected randomly from the IF-negative/PA-positive donors were PAI-positive. The majority (80%) of such PAI-positive sera showed more than two bands of HTLV-I gag-encoded polypeptide, p19, p24, p28 and p53 on Western blotting. Some of the PAI-positive sera were also positive by enzyme immunoassay. These results indicate that at least some of the IF-negative/PA-positive donors possess HTLV-I-specific antibody and may be potential HTLV-I carriers who will become IF-positive at a later age.

Preparation of virus-free pyridoxylated hemoglobin from the blood of HBV or HTLV-I healthy carriers.

One of our major aims was to find ways to utilize outdated or virus-contaminated blood. Pyridoxylated hemoglobin (PLP-Hb), a possible substitute for red cells as an artificial oxygen carrier was prepared from outdated human blood. By conjugation with polyethylene glycol (PEG), the biological half life was increased about 3 folds at 82% blood replacement in rats without significant side effects in vivo or in vitro. We next tried to prepare virus-free PEG-PLP-Hb from HBV or HTLV-I positive blood. A considerable amount of HBV (Dane particles) could be removed from HBV-positive red cells by washing and during the preparation of PEG-PLP-Hb. When the hemoglobin preparations containing Dane particles were filtered through a porous cellulose filter, BMM-30 (30 nm pore size, Asahi Chemical Industry Co., Ltd., Osaka, Japan), HBV-DNA in the filtered fractions became less than 0.33% of the initial amount. More than 96% of blood leukocytes could be removed with a leukocyte removal filter, Sepacell R-500 (Asahi Medical Co., Ltd., Tokyo, Japan). The leukocytes collected from filtrated fractions of HTLV-I positive blood did not survive beyond 3 days. Since transmission of HTLV-I occurs by cell to cell contact and is rare in cell-Free condition, it is unlikely that the PLP-Hb prepared from HTLV-I positive blood which is deprived of leukocytes transmits HTLV-I infection.

[Epidemiological studies of adult T-cell leukemia virus in patients with adult T-cell leukemia (ATL) and ATL-related diseases in Hokkaido District of Japan].

Sera and peripheral blood lymphocytes in 40 clinical cases of adult T-cell leukemia (ATL) and 66 cases of mature T-cell malignancies in Hokkaido district, the most northern part of Japan, were examined for the infection with ATL virus (ATLV). All of the 40 ATL patients (100%) had antibodies to ATLV-associated antigen (ATLA) and 13 (19.7%) of the 66 patients with mature T-cell malignancies other than ATL were also positive for anti-ATLA. When the peripheral ATL lymphocytes were assessed after short time cultivation, both ATLA antigen and C type virus particles were detectable. In contrast to the high prevalence of ATLV antibodies in these patients, the positivity in 30,000 control individuals in this district was 0.73%. It was calculated that 8 patients of a 40,000 seropositive population are diagnosed annually as ATL in this particular northern part of Japan.

[Prevalence of antibody to adult T-cell leukemia virus in Hokkaido District].

In order to investigate the spread of adult T-cell leukemia (ATL) virus in the inhabitants of ATL-non-endemic Hokkaido, we surveyed the antibodies to ATL-associated antigen (ATLA) in 29516 healthy individuals by indirect immunofluorescence test using MT-1 for target cell. Of the healthy inhabitants, only 219 individuals (0.74%) were anti-ATLA positive as carriers. Prevalence of anti-ATLA was 0.63% (111 of 17590) in males and 0.91% (108 of 11926) in females. This difference by sex is significant. In several regions, the inhabitants were found to show relatively high incidence (greater than 2%) of the antibodies, and these regions have a tendency to cluster around the western side of Hidaka mountains or Akan area. The highest rate (5.2%) of anti-ATLA positive carriers was shown in a certain town of Hidaka area.