Living-donor lobar lung transplantation from a hepatitis B surface antigen-positive donor to a negative recipient

A man in his 40s was diagnosed with interstitial pneumonia at another hospital. He was referred to our hospital for lung transplantation. His lung function was rapidly declining, necessitating semiurgent living-donor lobar lung transplantation (LDLLT). Although he was negative for hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (HBsAb), one of the candidate donors was proven HBsAg-positive. The risk of hepatitis B virus (HBV) infection at transplantation was considered high; however, after careful discussion about the safety of the recipient and donor, it was decided to conduct LDLLT. For prophylaxis, human anti-HBV surface immunoglobulin and entecavir were administered to the recipient. HBsAg and HBsAb were continuously monitored postoperatively and consistently negative, suggesting no signs of reactivation in the recipient, even after corticosteroid pulse treatment for acute cellular rejection. More than 6 months after LDLLT, there were no signs of HBV reactivation in either the recipient or donor.

Timeline of Oxygen Demand in Patients with COVID-19 Pneumonia

Objective In patients with coronavirus disease 2019 (COVID-19), understanding the timeline of oxygen demand and severe respiratory failure, such as intensive care unit (ICU) admission, may clarify the therapeutic window when home-care treatment is possible and help determine the timing of treatment in hospitalized patients to improve the respiratory status. We examined the timeline of respiratory status in hospitalized patients with moderate-to-severe COVID-19 in terms of oxygen demand and ICU admission. Methods We retrospectively assessed all patients with COVID-19 who were admitted to our hospital between February 2020 and February 2021 and required supplemental oxygen. This study included 66 patients who were transferred to the ICU (ICU patients) and 144 patients who were not transferred to the ICU (non-ICU patients). Results In the total cohort, the median duration from symptom onset to the need for supplemental oxygen was 8 [interquartile range (IQR) 6-10] days. This duration was significantly shorter in ICU patients than in non-ICU patients [8 (IQR 6-9) vs. 9 (IQR 6-10) days, p=0.02]. The median duration from symptom onset to ICU admission was 9 (IQR 8-11) days in severely ill patients. The median duration from the initiation of supplemental oxygen to ICU admission was 1.0 (IQR 1-2.75) days. Only 2 of 66 patients (3.0%) were admitted to the ICU six days or later after the initiation of supplemental oxygen. Conclusion Physicians should carefully monitor each patient's condition after eight days from symptom onset. New therapies and their early administration are needed to reduce the frequency of respiratory failure in COVID-19 patients.

Outcome of COVID-19 in interstitial lung disease patients treated with anti-inflammatory drugs and antiviral drugs

A recent study reported that patients with interstitial lung disease (ILD) are at increased risk of death from coronavirus disease 2019 (COVID-19). However, there are no studies on the outcome of COVID-19 patients with preexisting ILD treated with corticosteroids or antiviral drugs. We extracted 26 patients with preexisting ILD by medical records and HRCT pattern. Of 503 patients with COVID-19, we selected 52 patients as control matched for age and sex. Twenty out of the 26 ILD patients (76.9%) received corticosteroid therapy, and 23 patients (88.5%) also received antiviral treatment with remdesivir or favipiravir. Although no statistical difference was found, the proportion of severe patients in ILD group tended to be higher than in non-ILD group (23.1% vs. 42.3%; p = 0.114). Also, mortality rate in ILD group tended to be higher than in non-ILD patients (11.5% vs. 3.8%; p = 0.326). In univariate analysis to evaluate risk factors for severe condition, diagnosis of idiopathic pulmonary fibrosis, usual interstitial pneumonia pattern, and honeycomb lung were not risk factors of severe disease. Treatment with corticosteroids, antiviral drugs, and immunosuppressive agents may affect the outcome of COVID-19 patients with ILD.

Successful treatment with afatinib following the failure of osimertinib rechallenge with osimertinib-induced interstitial lung disease: A case report

Herein, we report the case of an 84-year-old woman with epidermal growth factor receptor (EGFR) mutation exon 19 deletion postoperative recurrent lung adenocarcinoma. Osimertinib was administered as a first-line treatment; however, she was urgently admitted to our hospital due to dyspnea on the 46th day. Chest computed tomography revealed bilateral diffuse ground-glass opacities (GGOs) suggestive of grade 3 osimertinib-induced interstitial lung disease (ILD). After discontinuation of osimertinib in combination with short-term corticosteroid therapy, widespread GGOs were promptly resolved. As the disease gradually deteriorated after discontinuation of osimertinib, we administered osimertinib (80 mg every other day) followed by careful observation. However, bilateral GGOs re-appeared on the 15th day, and the diagnosis of osimertinib-induced ILD was established. After the improvement in ILD following corticosteroid therapy, afatinib was administered as salvage therapy, resulting in desirable control of lung cancer without any relapse of ILD. Our results indicate that afatinib would be a promising alternative treatment option even in patients who develop osimertinib-induced ILD and experience failure of osimertinib rechallenge.

Serum Krebs von den Lungen-6 levels are associated with mortality and severity in patients with coronavirus disease 2019

Background

The serum Krebs von den Lungen-6 (KL-6) level is a predictive factor for acute respiratory distress syndrome (ARDS). The development of ARDS has been reported in patients with coronavirus disease 2019 (COVID-19). This study aimed to determine whether serum KL-6 levels are associated with mortality and severity in patients with COVID-19.

Methods

Among 361 Japanese patients with COVID-19 who were hospitalized at Kanagawa Cardiovascular and Respiratory Center between February 2020 and December 2020, 356 patients with data on serum KL-6 levels were enrolled and their medical records were retrospectively analyzed.

Results

A negative correlation was observed between KL-6 levels and the ratio of the arterial partial pressure of oxygen to the fraction of inspired oxygen on admission. The KL-6 levels on admission and the maximal KL-6 levels were higher in patients with severe disease (n = 60) than in those with nonsevere disease (n = 296). Furthermore, the maximal KL-6 levels were higher in nonsurvivors (n = 6) than in survivors (n = 350). In nonsurvivors, the KL-6 levels increased as the disease progressed. The optimal cutoff value of the maximal KL-6 level for discriminating between survivors and nonsurvivors was 684 U/mL, with a sensitivity of 83.3%, a specificity of 90.5%, and an area under the curve of 0.89.

Conclusions

The serum KL-6 level was associated with disease severity. Patients with KL-6 levels ≥684 U/mL had a significantly poorer outcome than those with KL-6 levels <684 U/mL.

Clinical characteristics of Japanese patients with moderate to severe COVID-19

INTRODUCTION

Although several reports on the risk factors for severe disease of COVID-19 already exist, reports on effective early indicators are still limited, especially from Japan. This study was conducted to clarify the patient's characteristics whose disease progressed to severe status.

METHODS

The medical records of all consecutive 300 Japanese patients hospitalized at our institution between February and November 2020 were retrospectively reviewed. The clinical characteristics were evaluated to compare between mild (no oxygen needed), moderate (oxygen needs of 1-4 L/min), and severe diseases (oxygen needs of 5 L/min or more).

RESULTS

The median age was 68 years old, with 123 (41.0%) males and 177 (59.0%) females. Of these, 199 patients (66.3%), 55 patients (18.3%), 46 patients (15.3%) patients were in the mild disease, moderate disease, severe disease groups, respectively. Patients with severe disease were more likely to be older, have more comorbidities, and tended to have higher body mass index. In laboratory data, lymphocyte count, levels of C-reactive protein (CRP), LDH, and AST on admission were significantly associated with the severity. In multivariate analysis, age and CRP were the independent risk factors for severe disease (OR = 1.050, 1.130, respectively). The optimal cut-off value for age was 74 years old and that for CRP was 3.15 mg/dL.

CONCLUSIONS

Age and CRP were independently associated with disease severity of COVID-19 in multivariate analysis. Additionally, the numbers of underlying disease, lymphocyte count, and inflammatory markers such as LDH and D-dimer may also be related to disease severity.

Pneumothorax in a COVID-19 Pneumonia Patient without Underlying Risk Factors

Coronavirus disease 2019 (COVID-19) has been recognized as a worldwide pandemic. However, the clinical course of COVID-19 remains poorly characterized. Although some cases of pneumothorax have been reported, they all had pulmonary complications or were managed with mechanical ventilation. We herein report a case of pneumothorax that developed even though the patient had no pulmonary underlying diseases and had never been managed with mechanical ventilation. In the present case, a lung bulla was found on chest computed tomography during treatment for COVID-19. We concluded that COVID-19 affected the formation of the lung bulla and induced the complication of pneumothorax.

Outcome of early-stage combination treatment with favipiravir and methylprednisolone for severe COVID-19 pneumonia: A report of 11 cases

Although the use of corticosteroids is not recommended in the World Health Organization statement for the treatment of coronavirus disease 2019 (COVID-19), steroid therapy may be indicated for critical cases in specific situations. Here, we report the successful treatment of 11 cases of severe COVID-19 pneumonia with favipiravir and methylprednisolone. All cases were severe and patients required oxygen administration or had a blood oxygen saturation ≤93% on room air. All were treated with favipiravir and methylprednisolone, and 10 of 11 patients responded well and required no further oxygen supplementation or ventilator management. This study shows the importance of the early-stage use of a combination of favipiravir and methylprednisolone in severe cases to achieve a favorable clinical outcome.

Five cases of BRAF V600E-mutant lung adenocarcinoma with high expression of programmed death ligand 1

We reported consecutive five patients with BRAF V600E-mutant recurrent or advanced non-small cell lung cancer who were identified between April 2016 and June 2019. All five patients had high programmed death ligand 1 (PD-L1) tumor proportion scores (50, 55, 75, 95 and 100%). Four of the five patients received regimens including pembrolizumab. Of them, one patient experienced a partial response, but two patients experienced progressive disease and one patient was not evaluable. Three of the four patients received regimens including pemetrexed were able to continue long-term treatment. The presence of a BRAF mutation may be associated with higher levels of PD-L1 expression. The effect of immune checkpoint inhibitors therapy in patients with BRAF mutation was similar to the previous reports in patients with previously treated advanced non-small cell lung cancer with PD-L1 tumor proportion score ≥50%. Chemotherapy regimens including pemetrexed may have a positive effect in patients with BRAF V600E-mutant lung adenocarcinoma. Accumulation of additional Case series is necessary to confirm our results.

Ultra-high-resolution computed tomography can demonstrate alveolar collapse in novel coronavirus (COVID-19) pneumonia

PURPOSE

To review the chest computed tomography (CT) findings on the ultra-high-resolution CT (U-HRCT) in patients with the Novel coronavirus disease 2019 (COVID-19).

MATERIALS AND METHODS

In February 2020, six consecutive patients with COVID-19 pneumonia (median age, 69 years) underwent U-HR CT imaging. U-HR-CT has a larger matrix size of 1024 × 1024 thinner slice thickness of 0.25 mm and can demonstrate terminal bronchioles in the normal lungs; as a result, Reid's secondary lobules and their abnormalities can be identified. The distribution and hallmarks (ground-glass opacity, consolidation with or without architectural distortion, linear opacity, crazy paving) of the lung opacities on U-HRCT were visually evaluated on a 1 K monitor by two experienced reviewers. The CT lung volume was measured, and the ratio of the measured lung volume to the predicted total lung capacity (predTLC) based on sex, age and height was calculated.

RESULTS

All cases showed crazy paving pattern in U-HRCT. In these lesions, the secondary lobules were smaller than those in the un-affected lungs. CT lung volume decreased in two cases comparing predTLC.

CONCLUSION

U-HRCT can evaluate not only the distribution and hallmarks of COVID-19 pneumonia but also visualize local lung volume loss.

A case of intrathoracic desmoid tumor with pulmonary Mycobacterium abscessus disease

A 68-year-old man who was on treatment for pulmonary Mycobacterium avium complex complained a worsening of sputum. Although he archived negative sputum culture two months ago, sputum culture tests revealed the newly isolation of Mycobacterium abscessus repeatedly. Chest computed tomography showed newly-appeared extra-pulmonary mass lesion in contact with a cyst at the bottom of his right lung. From the results of contrast-enhanced magnetic resonance imaging, we first suspected loculated pleural effusion due to Mycobacterium abscessus infection. A thoracoscopic examination was performed as the right pneumothorax developed, and the pleural lesion was successfully resected and diagnosed as an intrathoracic desmoid tumor. Intrathoracic desmoid tumor is very rare, and this is the first report of a case with pulmonary Mycobacterium abscessus disease.

Pembrolizumab-associated bronchiolitis in an elderly lung cancer patient required the treatment with an inhaled corticosteroid, erythromycin and bronchodilators

Immune checkpoint inhibitors (ICIs) have been used to treat lung cancer. Several types of ICI-related interstitial lung diseases have been reported, including organizing pneumonia, non-specific interstitial pneumonia, and diffuse alveolar damage. However, pembrolizumab-associated bronchiolitis requiring treatment for persistent cough has not yet been reported. Here, we describe a patient who developed dry cough while being treated with pembrolizumab for lung adenocarcinoma. Radiography and lung biopsy findings indicated bronchiolitis. His cough improved after the discontinuation of pembrolizumab and treatment with erythromycin, an inhaled corticosteroid, a long-acting muscarinic antagonist, and a long-acting β₂ agonist.

Experimental validation of the FLUKA Monte Carlo code for dose and [Formula: see text]-emitter predictions of radioactive ion beams

In the context of hadrontherapy, whilst ions are capable of effectively destroying radio resistant, deep seated tumors, their treatment localization must be well assessed to ensure the sparing of surrounding healthy tissue and treatment effectiveness. Thus, range verification techniques, such as online positron-emission-tomography (PET) imaging, hold great potential in clinical practice, providing information on the in vivo beam range and consequent tumor targeting. Furthermore, [Formula: see text] emitting radioactive ions can be an asset in online PET imaging, depending on their half-life, compared to their stable counterparts. It is expected that using these radioactive ions the signal obtained by a PET apparatus during beam delivery will be greatly increased, and exhibit a better correlation to the Bragg Peak. To this end, FLUKA Monte Carlo particle transport and interaction code was used to evaluate, in terms of annihilation events at rest and dose, the figure of merit in using [Formula: see text] emitter, radioactive ion beams (RI [Formula: see text]). For this purpose, the simulation results were compared with experimental data obtained with an openPET prototype in various online PET acquisitions at the Heavy Ion Medical Accelerator in Chiba (HIMAC), in collaboration with colleagues from the National Institute of Radiological Sciences' (NIRS) Imaging Physics Team. The dosimetry performance evaluation with FLUKA benefits from its recent developments in fragmentation production models. The present work estimated that irradiations with RI [Formula: see text], produced via projectile fragmentation and their signal acquisition with state-of-the-art PET scanner, lead to nearly a factor of two more accurate definition of the signals' peak position. In addition to its more advantageous distribution shape, it was observed at least an order magnitude higher signal acquired from ¹¹C and ¹⁵O irradiations, with respect to their stable counterparts.

Fine mapping of a major quantitative trait locus, qLG-9, that controls seed longevity in rice (Oryza sativa L.)

We fine-mapped a quantitative trait locus, qLG - 9, for seed longevity detected between Japonica-type and Indica-type cultivars. qLG - 9 was mapped in a 30-kb interval of the Nipponbare genome sequence. A quantitative trait locus, qLG-9, for seed longevity in rice has previously been detected on chromosome 9 by using backcross inbred lines derived from a cross between Japonica-type (Nipponbare) and Indica-type (Kasalath) cultivars. In the present study, the chromosomal location of qLG-9 was precisely determined by fine-scale mapping. Firstly, allelic difference in qLG-9 was verified by QTL analysis of an F2 population derived from a cross between Nipponbare and NKSL-1, in which a segment of Kasalath chromosome 9 was substituted in Nipponbare genetic background. Then, we selected F2 plants in which recombination had occurred near qLG-9 and performed F3 progeny testing on these plants to determine the genotype classes of qLG-9. Eventually, qLG-9 was mapped in a 30-kb interval (defined by two markers, CAPSb and CHPa12) of the Nipponbare genome sequence. This allowed us to nominate positional candidate genes of qLG-9. Additionally, we developed near-isogenic lines (NIL) for qLG-9 by marker-assisted selection. qLG-9 NIL showed significantly higher seed longevity than isogenic control of Nipponbare. These results will facilitate cloning of the gene(s) underlying qLG-9 as well as marker-assisted transfer of desirable genes for seed longevity improvement in rice.

A Ca(2+)-dependent protein kinase that endows rice plants with cold- and salt-stress tolerance functions in vascular bundles

A rice Ca(2+)-dependent protein kinase, OsCDPK7, is a positive regulator commonly involved in the tolerance to cold and salt/drought. We carried out in situ detection of the transcript and immunolocalization of the protein. In the wild-type rice plants under both stress conditions, OsCDPK7 was expressed predominantly in vascular tissues of crowns and roots, vascular bundles and central cylinder, respectively, where water stress occurs most severely. This enzyme was also expressed in the peripheral cylinder of crown vascular bundles and root sclerenchyma. Similar localization patterns with stronger signals were observed in stress-tolerant OsCDPK7 over-expressing transformants with the cauliflower mosaic virus 35S promoter. The transcript of a putative target gene of the OsCDPK7 signaling pathway, rab16A, was also detected essentially in the same tissues upon salt stress, suggesting that the OsCDPK7 pathway operates predominantly in these regions. We propose that the use of the 35S promoter fortuitously strengthened the localized expression of OsCDPK7, resulting in enhancement of the stress signaling in the inherently operating regions leading to improved stress tolerance.

Mapping of QTLs associated with cytosolic glutamine synthetase and NADH-glutamate synthase in rice (Oryza sativa L.)

Ninety-eight backcross inbred lines (BC1F6) developed between Nipponbare, a japonica rice, and Kasalath, an indica rice were employed to detect putative quantitative trait loci (QTLs) associated with the contents of cytosolic glutamine synthetase (GS1; EC 6.3.1.2) and NADH-glutamate synthase (NADH-GOGAT; EC 1.4.1.14) in leaves. Immunoblotting analyses showed transgressive segregations toward lower or greater contents of these enzyme proteins in these backcross inbred lines. Seven chromosomal QTL regions for GS1 protein content and six for NADH-GOGAT protein content were detected. Some of these QTLs were located in QTL regions for various biochemical and physiological traits affected by nitrogen recycling. These findings suggested that the variation in GS1 and NADH-GOGAT protein contents in this population is related to the changes in the rate of nitrogen recycling from senescing organs to developing organs, leading to changes in these physiological traits. Furthermore, a structural gene for GS1 was mapped between two RFLP markers, C560 and C1408, on chromosome 2 and co-located in the QTL region for one-spikelet weight. A QTL region for NADH-GOGAT protein content was detected at the position mapped for the NADH-GOGAT structural gene on chromosome 1. A QTL region for soluble protein content in developing leaves was also detected in this region. Although fine mapping is required to identify individual genes in the future, QTL analysis could be a useful post-genomic tool to study the gene functions for regulation of nitrogen recycling in rice.

High-resolution image reconstruction method for time-of-flight positron emission tomography

We present a new image reconstruction method for time-of-flight positron emission tomography (TOF-PET). The TOF-PET measurement system is modelled using the continuous-discrete mapping model, and images are reconstructed using an algebraic technique. The proposed method can produce images with better spatial resolution than conventional methods based on the filtered backprojection method. Numerical simulation results show that accurate modelling of the measurement system improves the spatial resolution and the contrast recovery, while the utilization of TOF information improves the signal-to-noise ratios of images.

AtPex14p maintains peroxisomal functions by determining protein targeting to three kinds of plant peroxisomes

We previously isolated an Arabidopsis: peroxisome-deficient ped2 mutant by its resistance to 2,4-dichlorophenoxybutyric acid. Here, we describe the isolation of a gene responsible for this deficiency, called the PED2 gene, by positional cloning and confirmed its identity by complementation analysis. The amino acid sequence of the predicted protein product is similar to that of human Pex14p, which is a key component of the peroxisomal protein import machinery. Therefore, we decided to call it AT:Pex14p. Analyses of the ped2 mutant revealed that AT:Pex14p controls intracellular transport of both peroxisome targeting signal (PTS)1- and PTS2-containing proteins into three different types of peroxisomes, namely glyoxysomes, leaf peroxisomes and unspecialized peroxisomes. Mutation in the PED2 gene results in reduction of enzymes in all of these functionally differentiated peroxisomes. The reduction in these enzymes induces pleiotropic defects, such as fatty acid degradation, photorespiration and the morphology of peroxisomes. These data suggest that the AT:Pex14p has a common role in maintaining physiological functions of each of these three kinds of plant peroxisomes by determining peroxisomal protein targeting.

Organ and cellular localization of asparagine synthetase in rice plants

DNA gel blot analysis suggested that asparagine synthetase (AS; EC 6.3.5.4) occurred as a single gene in rice. A fusion protein consisting of 17 kDa tagged-region from pET32a(+) expression plasmid and 42 kDa N-terminal region of rice AS was first expressed in Escherichia coli. The resulting polypeptide was purified and a mono-specific antibody for rice AS was prepared after affinity-purification with the antigen. Immunoblotting revealed a high content of AS protein in the leaf sheath at the second position from the fully expanded top leaf and in grains at the middle stage of ripening. Accumulation of mRNA for AS was also observed in these organs. During the ripening of the spikelets, the AS protein contents increased during the first 21 days after flowering, then declined rapidly. Immunolocalization analysis revealed signals for AS protein in the companion cells of vascular bundles of leaf sheath and phloem-parenchyma cells, nucellar projection, and nucellar epidermis of dorsal vascular bundles of grains.

Okadaic Acid Mimics Nitrogen-Stimulated Transcription of the NADH-Glutamate Synthase Gene in Rice Cell Cultures

Okadaic acid (OKA), a potent and specific inhibitor of protein serine/threonine phosphatases 1 and 2A, induced the accumulation of NADH-glutamate synthase (GOGAT) mRNA within 4 h in rice (Oryza sativa L.) cell cultures. In contrast to the transient accumulation of NADH-GOGAT mRNA by NH(4)(+), OKA caused a continuous accumulation for at least 24 h. The induction of NADH-GOGAT mRNA by OKA was not inhibited in the presence of methionine sulfoximine, which inhibited the NH(4)(+)-induced accumulation of mRNA. These results suggest that the OKA-sensitive protein phosphatase is involved in the regulation of NADH-GOGAT gene expression and probably plays a role in the signal transduction pathway downstream from NH(4)(+), although a signal transduction pathway other than that of nitrogen sensing could be responsible. Nuclear run-on assays demonstrated that the accumulation of NADH-GOGAT mRNA induced by the supply of either NH(4)(+) or OKA was mainly regulated at the transcription level. OKA effects were synergistic to the NH(4)(+)-induced expression of the NADH-GOGAT gene. In the presence of K-252a, a protein kinase inhibitor, the accumulation of NADH-GOGAT mRNA induced by either NH(4)(+) or OKA was reduced. The possible roles of protein phosphatases in the regulation of NADH-GOGAT gene expression are discussed.

Organization and structure of NADH-dependent glutamate synthase gene from rice plants

Genomic clones for NADH-dependent glutamate synthase (NADH-GOGAT; EC 1.4.1.14) were obtained from a genomic library of rice (Oryza sativa L. cv. Sasanishki). A genomic clone (lambdaOS42, 14 kb) covered an entire structural gene and a 3.7 kb 5'-upstream region from the first methionine. Another clone (lambdaOS23, 14 kb) contained a 2.8 kb 3'-downstream region from the stop codon. A 7047 bp long clone (lambdaOSR51) consisting of full length cDNA for NADH-GOGAT was isolated from a cDNA library prepared using mRNA from roots of rice seedlings treated with 1 mM NH4Cl for 12 h. The presumed transcribed region (11.7 kb) consisted of 23 exons separated by 22 introns. Rice NADH-GOGAT is synthesized as a 2166 amino acid protein with a molecular mass of 236.7 kDa that includes a 99 amino acid presequence. DNA gel blot analysis suggested that NADH-GOGAT occurred as a single gene in rice. Primer extension experiments map the transcription start of NADH-GOGAT to identical positions. The 3. 7 kb 5'-upstream region was able to transiently express a reporter gene in cultured rice cells. Putative motifs related to the regulation of NADH-GOGAT gene expression were looked for within the 5'-upstream region by database.

Expression of NADH-dependent glutamate synthase protein in the epidermis and exodermis of rice roots in response to the supply of ammonium ions

The mRNA and protein for NADH-dependent glutamate synthase (NADH-GOGAT; EC 1.4.1.14) in root tips of rice (Oryza sativa L. cv. Sasanishiki) plants increases dramatically within 12 h of supplying a low concentration (> 0.05 mM) of ammonium ions (T. Yamaya et al., 1995, Plant Cell Physiol 36: 1197-1204). To identify the specific cells which are responsible for this rapid increase, the cellular localization of NADH-GOGAT protein was investigated immunocytologically with an affinity-purified anti-NADH-GOGAT immunoglobulin G. When root tips (> 1 mm) of rice seedlings which had been grown for 26 d in water were immuno-stained, signals for the NADH-GOGAT protein were detected in the central cylinder, in the apical meristem, and in the primordia of the secondary roots, Signals for ferredoxin-dependent GOGAT (Fd-GOGAT; EC 1.4.7.1) protein were also seen in the same three areas. When the roots were supplied with 1 mM ammonium ions for 24 h, there were strong signals for the NADH-GOGAT protein in two cell layers of the root surface, i.e. epidermis and exodermis, in addition to the cells giving signals in the absence of ammonium ions. The supply of ammonium ions was less effective on the profile of signals for Fd-GOGAT. Although the supply of ammonium ions had less effect on the expression of cytosolic glutamine synthetase (GS; EC 6.3.1.2), this enzyme was also found to be located in the epidermis and exodermis, as well as in the central cylinder and cortex. The results indicate that NADH-GOGAT, coupled to the cytosolic GS reaction, is probably important for the assimilation of ammonium ions in the two cell layers of the root surface.

Changes in the Content of Two Glutamate Synthase Proteins in Spikelets of Rice (Oryza sativa) Plants during Ripening

Nitrogen accumulation in the apical spikelets on the primary branches of the main stem of rice plants have been studied during the ripening process (0-35 d after flowering). The level of NADH-dependent glutamate synthase (GOGAT) protein and activity increased 4- and 6-fold, respectively, in the first 15 d after flowering. Maximum levels of NADH-GOGAT were found at that time when the spikelets had just begun to increase in dry weight and to accumulate storage proteins. Subsequently, both the level of NADH-GOGAT protein and its activity in spikelets declined rapidly. Although changes in ferredoxin (Fd)-dependent GOGAT paralleled changes in NADH-GOGAT, the relative abundance of NADH-GOGAT protein in the spikelets was about 3 times higher than that of Fd-GOGAT from 5 to 15 d after flowering. When the chaff (lemma and palea) was separated from the spikelets 10 d after the flowering, 16% of the NADH-GOGAT protein was found in the chaff and 84% in the young grain tissues (endosperm, testae, aleurone tissues, and embryo). On the other hand, Fd-GOGAT protein was distributed 52% in the chaff and 48% in the young grain tissues in spikelets of the same age. Activity of NADP-isocitrate dehydrogenase, which may generate the 2-oxoglutarate required for the GOGAT reactions, was much higher than that of total GOGAT activities on a spikelet basis during the ripening process. These results suggest that in rice plants NADH-GOGAT is responsible for the synthesis of glutamate from the glutamine that is transported from senescing tissues to the spikelets.

Tissue Distribution of Glutamate Synthase and Glutamine Synthetase in Rice Leaves : Occurrence of NADH-Dependent Glutamate Synthase Protein and Activity in the Unexpanded, Nongreen Leaf Blades

To further explore the function of NADH-dependent glutamate synthase (GOGAT), the tissue distribution of NADH-GOGAT protein and activity was investigated in rice (Oryza sativa L.) leaves. The distributions of ferredoxin (Fd)-dependent GOGAT, plastidic glutamine synthetase, and cytosolic glutamine synthetase proteins were also determined in the same tissues. High levels of NADH-GOGAT protein (33.1 mug protein/g fresh weight) and activity were detected in the 10th leaf blade before emergence. The unexpanded, nongreen portion of the 9th leaf blade contained more than 50% of the NADH-GOGAT protein and activity per gram fresh weight when compared with the 10th leaf. The expanding, green portion of the 9th leaf blade outside of the sheath contained a slightly lower abundance of NADH-GOGAT protein than the nongreen portion of the 9th blade on a fresh weight basis. The fully expanded leaf blades at positions lower than the 9th leaf had decreased NADH-GOGAT levels as a function of increasing age, and the oldest, 5th blade contained only 4% of the NADH-GOGAT protein compared with the youngest 10th leaf blade. Fd-GOGAT protein, on the other hand, was the major form of GOGAT in the green tissues, and the highest amount of Fd-GOGAT protein (111 mug protein/g fresh weight) was detected in the 7th leaf blade. In the nongreen 10th leaf blade, the content of Fd-GOGAT protein was approximately 7% of that found in the 7th leaf blade. In addition, the content of NADH-GOGAT protein in the 10th leaf blade was about 4 times higher than that of Fd-GOGAT protein. The content of plastidic glutamine synthetase polypeptide was also the highest in the 7th leaf blade (429 mug/g fresh weight) and lowest in nongreen blades and sheaths. On the other hand, the relative abundance of the cytosolic glutamine synthetase polypeptide was the highest in the oldest leaf blade, decreasing to 10 to 20% of that value in young, nongreen leaves. These results suggest that NADH-GOGAT is important for the synthesis of glutamate from the glutamine that is transported from senescing source tissues through the phloem in the nongreen sink tissues in rice leaves.

Vascular bundle-specific localization of cytosolic glutamine synthetase in rice leaves

Tissue localizations of cytosolic glutamine synthetase (GS1; EC 6.3.1.2), chloroplastic GS (GS2), and ferredoxin-dependent glutamate synthase (Fd-GOGAT; EC 1.4.7.1) in rice (Oryza sativa L.) leaf blades were investigated using a tissue-print immunoblot method with specific antibodies. The cross-sections of mature and senescent leaf blades from middle and basal regions were used for tissue printing. The anti-GS1 antibody, raised against a synthetic 17-residue peptide corresponding to the deduced N-terminal amino acid sequence of rice GS1, cross-reacted specifically with native GS1 protein, but not with GS2 after transfer onto a nitrocellulose membrane. Tissue-print immunoblots showed that the GS1 protein was located in large and small vascular bundles in all regions of the leaf blade prepared from either stage of maturity. On the other hand, GS2 and Fd-GOGAT proteins were mainly located in mesophyll cells. The intensity of the developed color on the membrane for GS1 was similar between the two leaf ages, whereas that for GS2 and Fd-GOGAT decreased during senescence. The tissue-specific localization of GS1 suggests that this GS isoform is important in the synthesis of glutamine, which is a major form of nitrogen exported from the senescing leaf in rice plants.

Changes in Cytosolic Glutamine Synthetase Polypeptide and its mRNA in a Leaf Blade of Rice Plants during Natural Senescence

Changes in the levels of cytosolic glutamine synthetase (GS1) and chloroplastic glutamine synthetase (GS2) polypeptides and of their corresponding mRNAs have been investigated in segments of the 13th leaf of hydroponically grown rice (Oryza sativa L.) plants during natural senescence. The leaf blade on the main stem at early (0 day), middle (15 days), and late (25 days) stages of senescence was harvested and cut into 18 or 19 segments, 2 centimeters in length from the base to the tip. The amount of GS1 polypeptide, detected with specific antibody for the GS1, was greatest near the middle of the leaf blade (segments 11-13). There was little difference in the GS1 content between corresponding leaf segments obtained at the early and middle stages of senescence. At the late senescence stage, all segments had lost some GS1 polypeptide, but more than 50% of GS1 detected at both the early and middle stages was still detectable in segments. The relative content of mRNA for GS1 in the total RNA in all segments was very low during early senescence but increased in all leaf segments during later senescence. At the late stage of senescence, GS1 mRNA in the total RNA increased about 4.2- to 4.6-fold in segments 12 to 16 in the day-25 samples compared with those in the early stage. The content of the GS2 polypeptide, as well as ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) protein, was highest in segment 17 in the 0-day samples. During senescence, this peak became lower and broader, and finally disappeared, i.e. approximately 80% of GS2 polypeptide and Rubisco protein in segment 17 were lost by day 25. In contrast with GS2 polypeptide, the relative level of GS2 mRNA increased 1.8- to 2.9-fold in individual segments at the middle stage of senescence. Even at the late stage, the transcript signals remained slightly higher than those at the early stage in all segments. Thus, GS1 and GS2 polypeptides and corresponding mRNAs responded in a different manner within an attached rice leaf during natural senescence. The contents of GS1 and GS2 polypeptides were not simply determined by the abundance of their corresponding mRNAs in the rice leaf blades during natural senescence.

Purification, Characterization, and Immunological Properties of NADH-Dependent Glutamate Synthase from Rice Cell Cultures

To obtain a monospecific antibody against NADH-dependent glutamate synthase (NADH-GOGAT; EC 1.4.1.14), the enzyme was purified to homogeneity from cultured rice cells (Oryza sativa) with column chromatography using Butyl Toyopearl 650M, Sephacryl S-300, Blue Sepharose CL-6B, and Butyl Toyopearl 650S. The specific activity at the final stage of the purification was 9.8 micromoles of glutamate formed per minute per milligram of protein. The yield was 6.1% and purification was 815-fold. Analysis by denaturing gel electrophoresis revealed a single polypeptide with an apparent molecular weight of 196,000, similar to the value of 194,000 estimated for the native protein. Apparent K(m) values for l-glutamine, 2-oxoglutarate, and NADH were 811, 76, and 3.0 micromolar, respectively. Neither NADPH nor l-asparagine substituted for NADH and l-glutamine, respectively. The enzyme had its absorption maxima at 273, 373, and 440 nanometers with a shoulder at 475 nanometers, suggesting that the rice NADH-GOGAT is a flavoprotein. Monospecific antibody raised against NADH-GOGAT purified from the rice cells was obtained as the first instance for the enzyme in higher plants. Immunological analyses showed that the antibody for rice cell NADH-GOGAT reacted with only the enzyme in extracts from the cells. The anti-NADH-GOGAT antibody did not recognize the ferredoxin-GOGAT purified from rice leaves, and likewise the anti-rice leaf ferredoxin-GOGAT antibody did not react with the NADH-GOGAT purified from the cultured rice cells.

A Role for Glutamine Synthetase in the Remobilization of Leaf Nitrogen during Natural Senescence in Rice Leaves

Changes in the levels of cytosolic glutamine synthetase (GS1) and chloroplastic glutamine synthetase (GS2) polypeptides and of corresponding mRNAs were determined in leaves of hydroponically grown rice (Oryza sativa) plants during natural senescence. The plants were grown in the greenhouse for 105 days at which time the thirteenth leaf was fully expanded. This was counted as zero time for senescence of the twelfth leaf. The twelfth leaf blade on the main stem was analyzed over a time period of -7 days (98 days after germination) to +42 days (147 days after germination). Total GS activity declined to less than a quarter of its initial level during the senescence for 35 days and this decline was mainly caused by a decrease in the amount of GS2 polypeptide. Immunoblotting analyses showed that contents of other chloroplastic enzymes, such as ribulose-1,5-bisphosphate carboxylase/oxygenase and Fd-glutamate synthase, declined in parallel with GS2. In contrast, the GS1 polypeptide remained constant throughout the senescence period. Translatable mRNA for GS1 increased about fourfold during the senescence for 35 days. During senescence, there was a marked decrease in content of glutamate (to about one-sixth of the zero time value); glutamate is the major form of free amino acid in rice leaves. Glutamine, the major transported amino acid, increased about threefold compared to the early phase of the harvest in the senescing rice leaf blades. These observations suggest that GS1 in senescing leaf blades is responsible for the synthesis of glutamine, which is then transferred to the growing tissues in rice plants.

Treatment of myelodysplastic syndromes with orally administered 1-beta-D-arabinofuranosylcytosine-5'-stearylphosphate

1-beta-D-Arabinofuranosylcytosine-5'-stearylphosphate (fosteabine) was administered orally to patients with myelodysplastic syndromes (MDS); refractory anemia with excess of blasts (RAEB), RAEB in transformation, acute leukemia derived from RAEB and chronic myelomonocytic leukemia, in an early phase II study in a multi-institutional study. Among 62 evaluable patients, 2 patients achieved a complete remission, 6 a good response and 8 partial response by daily oral administration of 100-200 mg of fosteabine. The overall response rate was 25.8%. The response rates were almost the same among the four subtypes of MDS. Responses were reached 2-23 weeks (median, 8 weeks) after the start of therapy and continued for 3-50 weeks (median, 10 weeks). Major side effects were myelosuppression and gastrointestinal toxicities. In spite of the disadvantages, such as unpredictable absorption, this newly developed orally administrable cytarabine analogue will be a useful drug in the treatment of MDS.

A case of malignant histiocytosis successfully treated with combination interferon and etoposide therapy

A 66-year-old woman with malignant histiocytosis was treated with a combination of recombinant gamma interferon (GI-3) and etoposide. Following partial response to intravenous gamma interferon (9 x 10(6) units (U)/day) alone, the patient received an eight-months course of subcutaneous gamma interferon (0.5 x 10(6) U/day) and intravenous etoposide (100 mg/week). After two years, the patient remains in complete remission. The present case report discusses the successful use of combination gamma interferon and etoposide for the treatment of malignant histiocytosis.

[An intensification therapy of adults acute leukemia]

Between January 1980 and March 1983, a study was conducted on the effects of intensification therapy in 20 adult acute leukemia patients who had achieved complete remission with induction therapy. Intensification therapy consisted of cyclic administration of six combination therapies given at gradually longer intervals, using daunorubicin, cytosine arabinoside, 6-mercaptopurine and prednisolone (DCMP), cyclocytidine (DCyMP), vincristine (DCVP), behenoyl-ara-c (BHAC-DMP), aclacinomycin (BHAC-AMP) and (ACM-MP). Six combinations were given sequentially at one-month intervals, at 2-, 3-, 4-, 5- and eventually 6-month intervals, until 5-year survival. The median remission duration was 38 months for AML, and 17 months for ALL. The median survival was 66 months for AML, and 37 months for ALL. The five year survival rate was 50%. Nine of the 20 patients are still alive. Methotrexate and prednisolone were administered intrathecally for prophylaxis of CNS leukemia on Day 4 for each intensification therapy. There was no CNS leukemia. This intensification protocol was shown to be effective in improving the prognosis of adults acute leukemia.

Synthesis of [N]glutamate from [N]h(4) and [N]glycine by mitochondria isolated from pea and corn shoots

Metabolically competent mitochondria were isolated from pea and corn shoots on Percoll discontinuous density gradients. Rates of synthesis of [(15)N]glutamate were measured by gas chromatography-mass spectrometry after the incubation of mitochondria with either 2 millimolar [(15)N] H(4) (+) or [(15)N]glycine in the presence of 1 millimolar citrate as the respiratory substrate. When [(15)N]H(4) (+) was provided, mitochondria isolated from light-grown pea shoots synthesized [(15)N]glutamate with a rate of 2.64 nanomoles per hour per milligram mitochondrial protein. Corn mitochondria produced [(15)N]glutamate at a rate approximately 11 times greater than the pea mitochondria. Dark treatment during growth for the last 24 hours caused a slight reduction in the rate of synthesis in both species. When [(15)N]glycine was used, pea mitochondria synthesized [(15)N]glutamate with a rate of 6.32 nanomoles per hour per milligram protein. Rapid disappearance of [(15)N]glycine and synthesis of [(15)N]serine was observed with a molar ratio of 2 glycine to 0.78 serine. The rate of glutamate synthesis was only 0.2% that of serine, due in part to the dilution of [(15)N]H(4) (+) by the [(14)N]H(4) (+) pool in the mitochondria. The majority of the [(15)N]H(4) (+) released from glycine appears to have been released from or remains unmetabolized in the mitochondria. Corn mitochondria showed no apparent disappearance of [(15)N]glycine and little synthesis of [(15)N]serine, indicating that our preparation originated primarily from mesophyll cells. Under our conditions of glycine/serine conversion, [(15)N]glutatmate was synthesized at a rate of 7% of that of [(15)N]serine synthesis by corn mitochondria.

Characteristics of glutamate dehydrogenase in mitochondria prepared from corn shoots

The amination of alpha-ketoglutarate (alpha-KG) by NADH-glutamate dehydrogenase (GDH) obtained from Sephadex G-75 treated crude extracts from shoots of 5-day-old seedlings was stimulated by the addition of Ca(2+). The NADH-GDH purified 161-fold with ammonium sulfate, DEAE-Toyopearl, and Sephadex G-200 was also activated by Ca(2+) in the presence of 160 micromolar NADH. However, with 10 micromolar NADH, Ca(2+) had no effect on the NADH-GDH activity. The deamination reaction (NAD-GDH) was not influenced by the addition of Ca(2+).About 25% of the NADH-GDH activity was solubilized from purified mitochondria after a simple osmotic shock treatment, whereas the remaining 75% of the activity was associated with the mitochondrial membrane fraction. When the lysed mitochondria, mitochondrial matrix, or mitochondrial membrane fraction was used as the source of NADH-GDH, Ca(2+) had little effect on its activity. The mitochondrial fraction contained about 155 nanomoles Ca per milligram of mitochondrial protein, suggesting that the NADH-GDH in the mitochondria is already in an activated form with regard Ca(2+). In a simulated in vitro system using concentrations of 6.4 millimolar NAD, 0.21 millimolar NADH, 5 millimolar alpha-KG, and 5 millimolar glutamate thought to occur in the mitochondria, together with 1 millimolar Ca(2+), 10 and 50 millimolar NH(4) (+), and purified enzyme, the equilibrium of GDH was in the direction of glutamate formation.

Pectic polysaccharide breakdown of cell walls in cucumber roots grown with calcium starvation

Pectic polysaccharides from the roots of cucumber (Cucumis sativus L.) grown in liquid culture medium with or without calcium (1 mm CaCl(2)) were studied after extraction successively by hot water and Na hexametaphosphate solution. The Ca(2+) starvation-treatment caused a striking reduction in content of extracted pectic polysaccharide; from an equivalent weight of cell walls, only 33.1% of the control level was extracted from root cell walls of plants cultured under Ca(2+) deficiency. The extracted pectic polysaccharides were fractionated into neutral and acidic polymers by a DEAE-Sephadex column. The acidic polymers, which represented more than 76% of the yield, appeared to be a major fraction of extracted pectic polysaccharides. The changes of molecular size and glycosyl residue composition of this fraction were compared for the control and Ca(2+)-deprived samples. The results indicate that Ca(2+) deficiency caused structural changes which could involve both branching pattern and extent of contiguous galacturonosyl units in the water-solubilized pectic polysaccharides. Ca(2+) starvation also led to a notable decrease in molecular size of the hexametaphosphate-solubilized polysaccharides and, to a lesser extent, of the water-solubilized fraction as well. In addition, polygalacturonase activity in tissue homogenates increased remarkably with the Ca(2+) deficiency, whereas beta-galactosidase activity did not undergo a change. Thus, it appears that one major effect of Ca(2+) deprivation was to stimulate polygalacturonase activity, an effect which could be involved in the control of the breakdown of pectic polysaccharides in the cell walls.