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Biomedical subjects

Y Ohta

Publications and source records attributed to Y Ohta.

At least 91 records · Page 5Linked to original sources

Inhibitory action of Oren-gedoku-to extract on enzymatic lipid peroxidation in rat liver microsomes.

We examined the inhibitory action of the extract of Oren-gedoku-to, a traditional herbal medicine known to act as an antioxidant, on enzymatic lipid peroxidation in rat liver microsomes. Simultaneous addition of a spray-dried preparation of Oren-gedoku-to extract (Tsumura TJ-15) inhibited enzymatic lipid peroxidation induced by reduced beta-nicotinamide adenine dinucleotide phosphate (NADPH) and ADP/Fe3+ complex in liver microsomes in a dose-dependent manner. When the inhibition by TJ-15 of enzymatic lipid peroxidation in liver microsomes was kinetically analyzed, this medicine showed a competitive inhibition against NADPH or ADP/Fe3+ complex. TJ-15 inhibited the NADPH-driven enzymatic reduction of ADP/Fe3+ complex or cytochrome c in liver microsomes competitively. TJ-15 enhanced NADPH consumption by liver microsomes with ADP/Fe3+ complex. Treatment with TJ-15 after the onset of enzymatic lipid peroxidation in liver microsomes inhibited the progression of lipid peroxidation in a dose-dependent manner. The present results indicate that Oren-gedoku-to extract inhibits enzymatic lipid peroxidation in rat liver microsomes in the initiation and propagation steps in a dose-dependent manner. These results also suggest that Oren-gedoku-to extract inhibits enzymatic lipid peroxidation in rat liver microsomes not only through its antioxidant action but also through reduction of the supply of electrons derived from NADPH to ADP/Fe3+ complex in liver microsomes both in a competitive manner and through stimulation of NADPH oxidation.

Adenosine Diphosphate↗

Doppler echocardiography-derived index of myocardial performance (TEI index): comparison with brain natriuretic peptide levels in various heart disease.

Plasma brain natriuretic peptide (BNP) has diagnostic and prognostic value in heart failure. Cardiac dysfunction varies from systolic or diastolic dysfunction alone to the combination of both. In the present study, Doppler echocardiographic parameters, including the Doppler echocardiography-derived index (TEI index), were compared with plasma BNP levels in 74 patients with various heart diseases. Blood sampling was performed before an echocardiographic examination was conducted. The TEI index was defined as the summation of isovolumic contraction and relaxation time divided by ejection time. In patients with left ventricular (LV) systolic dysfunction (ejection fraction <50%), the TEI index and BNP were increased significantly compared with patients with normal LV systolic function (p<0.05). Patients with a TEI index > or =0.45 showed significantly increased BNP levels compared with patients with a TEI index <0.45, irrespective of LV systolic function (241.4+/-451.2 vs 65.9+/-81.8pg/ml; p<0.05). The TEI index was significantly higher in patients with a BNP > or =73pg/ml than in patients with BNP <73pg/ml (0.57+/-0.24 vs 0.46+/-0.17; p<0.05). Other echocardiographic parameters did not correlate significantly with levels of plasma BNP. Of the echocardiographic parameters, a simple Doppler index (TEI index) that combines systolic and diastolic function can detect LV dysfunction in patients with high levels of plasma BNP in various heart diseases.

Adolescent↗

Production of phytase in a low phosphate medium by a novel yeast Candida krusei.

A yeast strain producing high levels of phytase was isolated from soil and identified as Candida krusei. The phytase was located on the yeast cell wall and was a glucanase-extractable protein. The phytase production was controlled by the phosphate concentration in the medium used. The maximum production of phytase occurred in a medium containing 0.5 mg of phosphorus per 100 ml, and most of the cells were ellipsoid-shaped and did not exhibit budding. Increasing the concentration of phosphorus in the medium to more than 5 mg of phosphorus per 100 ml caused inhibition of phytase production and 90% of the cells exhibited budding. On the other hand, transferring cells grown in the high-phosphate medium into a phosphate-free one derepressed the phytase production. For example, transferring cells grown in 2 mg of phosphorus per 100 ml into the phosphate-free medium, enhanced the total phytase activity up to 5.5-fold that in the medium containing 0.5 mg of phosphorus per 100 ml. The phytase showed two optimum pHs of 2.5 and 5.5, an optimum temperature of 40 degrees C and the K(m) value for Na-phytate was 0.03 mM. Using in vitro experiments that simulated the conditions of the digestive tract, 50-80% phosphorus was liberated from different plant samples (wheat bran, rice bran and feeds) by the strain.

Journal Article↗

Trends in the pathophysiological characteristics of malignant hypertension.

The aim of the present study is to investigate the pathophysiological characteristics of a number of recent cases of malignant hypertension (MHT) and to compare them to the characteristics of earlier cases. Patients with MHT (age 25-76, mean 44+/-2 years) who were admitted to our hospital from 1984-1999 were retrospectively studied. All of the patients had either grade III or IV retinopathy and diastolic blood pressure levels higher than 120 mmHg. The observations in this study were compared to previously reported findings regarding 59 MHT patients who were admitted from 1971-1983. Of the 37 recent MHT patients, 20 had essential hypertension (EHT) as the underlying disease, 13 had chronic glomerulonephritis (CGN), and the remaining 4 presented with other diseases including pyelonephritis and renovascular hypertension. A positive family history of hypertension was more prevalent in the EHT patients than in other patients, and persistent proteinuria, microhematuria, and anemia were more prevalent in the CGN patients. These characteristics were similar between the recent and previous cases. Within 4 weeks after admission, hemodialysis was initiated in 3 of the 13 patients (23%) with CGN and 2 of the 20 (10%) patients with EHT. The prevalence of renal death at 1 year after admission was 30%, which was lower than the prevalence in the previous cases (42%). Grade IV retinopathy was seen in 45% of the patients admitted from 1984-1999, significantly less than in the patients admitted from 1971-1983 (66%, p<0.05). In addition, left ventricular hypertrophy was less frequently observed on electrocardiogram in the recent cases (67%) than in the previous cases (88%, p<0.05). Our results suggest that the recent cases of MHT demonstrate less severe organ damage.

Adult↗

Metallothionein expression and tumor growth in the transplantable pregnancy-independent mouse mammary tumor.

In various human tumors, a metal binding protein, metallothionein (MT) is reported to play an important role in carcinogenesis. In the present preliminary study, MT expression and tumor growth were investigated in transplantable pregnancy-independent mammary tumors (TPIMT) derived from pregnancy-independent mammary tumors (PIMT) in GR/A mice, in order to study the possible role of MT in mammary carcinogenesis. TPIMT as well as PIMT showed MT expression in tumor cells in all of the successive transplantations. A negative correlation was observed between MT expression in transplanted tumor tissues and their growth in the hosts (r=-0.53, p<0.05). The present study indicates that MT is a useful marker of tumor progression in TPIMT.

Animals↗

Size and composition changes in diaphragmatic fibers in rats exposed to chronic hypercapnia.

OBJECTIVE: To test the hypothesis that chronic hypercapnia changes the composition of the respiratory muscle by continuous augmentation of ventilation. MATERIALS AND METHODS: Eighteen male Wistar rats were housed in 10% CO(2) in air for 19 weeks, and their minute ventilation V(E) was measured every 6 weeks. The diaphragm, excited at 19 weeks of exposure, was classified as fiber type I, IIa, or IIb. Cross-sectional areas of individual fibers were measured. Fibers with a target-like appearance on reduced nicotinamide adenine dinucleotide-tetrazolium reductase (NADH-TR) stain also were counted. The data were compared with those of rats kept in room air. RESULTS: The mean (+/- SD) PaCO(2) after 19 weeks of sustained hypercapnia was 71.0 +/- 4.7 mm Hg. The V(E) remained at a high level until 12 weeks of exposure, and then it significantly decreased at week 18. In a comparison with the control rats, a larger number of type I fibers and a smaller number of type IIb fibers were found in the diaphragm of the chronically hypercapnic rats. In addition, the latter group's cross-sectional area revealed fibers of a significantly smaller diameter. Target-like fibers were observed in 5% of the NADH-TR-stained fibers in the chronically hypercapnic rats but were not seen in the control rats. CONCLUSION: By increasing the ratio of fatigue-resistant fibers, the diaphragm was able to adapt to a sustained load induced by hypercapnia. However, this adaptive process was accompanied by a degenerative change in the tissue.

Animals↗

Effect of diethylstilbestrol on cell proliferation and expression of epidermal growth factor in the developing female rat reproductive tract.

To evaluate mechanisms of cell proliferation in the fetal female rat reproductive tract, diethylstilbestrol (DES) effects on cell division and estrogen receptor (ER), epidermal growth factor (EGF) and EGF receptor (EGF-R) expressions were determined from gestational day (GD) 15.5 to 21.5. Reproductive tracts were evaluated within three regions along the Müllerian duct axis; these were proximal, middle and caudal, which differentiate into oviduct, uterus and upper vagina respectively. In fetuses from non-treated dams, epithelial and mesenchymal proliferation, as evaluated by 5-bromo-2'-deoxyuridine incorporation, was decreased with development in all regions of the Müllerian duct. EGF levels were determined by immunohistochemistry. Müllerian epithelial EGF immunoreactivity was intense in the proximal and middle regions on GDs 15.5 and 17.5. EGF staining remained intense only in the proximal epithelia by GD 19.5 and was weak in the caudal epithelium, but substantially reduced throughout epithelia in all regions by GD 21.5. Thus, decreased cell proliferation correlated with decreased EGF expression in the developing Müllerian duct. DES (100 microg/kg body weight) was injected from GD 15 to 19 and female fetuses were collected on GD 19.5. DES increased Müllerian duct cell proliferation in the proximal epithelium and mesenchyme but decreased it in the caudal epithelium compared with oil-treated controls. No proliferative DES effect was observed in any cell type in the middle region. Müllerian duct EGF immunoreactivity was suppressed by DES compared with oil. Competitive RT-PCR indicated DES also decreased mRNAs for EGF, ERbeta1 and ERbeta2, but not ERalpha and EGF-R. These results indicate EGF may be an important regulatory factor of Müllerian duct cell proliferation, and that DES may alter cell proliferation by disrupting normal EGF, ERbeta1 and ERbeta2 expression in the developing female rat reproductive tract.

Animals↗

Biological characteristics of carcinomatosa pleuritis in orthotopic model systems using immune-deficient rats.

We assessed the association of vascular endothelial growth factor (VEGF) on the formation of carcinomatosa pleuritis in orthotopic model systems. Immune-deficient rats were inoculated with PC-14 cells into i) a subpleural space of the parietal pleura after pneumonectomy or ii) into the thoracic cavity directly. The rats bearing tumor cells were randomly separated into two groups: non-treatment and treatment with anti-VEGF neutralizing antibody groups. At the time of the autopsy, all rats developed gross pleural dissemination with/without malignant effusions. In the first model, despite no significant difference in the mean volume of the subpleural tumors between the groups, the degree of dissemination was suppressed in the treatment group with less tumor vasculature and with reduced expression of autocrine motility factor receptor (AMFR) in tumor cells. In the second model, although the inhibitory effect on dissemination was not clear, the formation of pleural effusion was inhibited in the treatment group. In addition to the ability of vascular permeability, the results demonstrated here showed the possible association of VEGF with the development of pleural dissemination/metastasis in the context of blood/lymphatic routes and cancer cell motility affected by AMFR.

Adenocarcinoma↗

[Carinal resection for bronchogenic carcinoma].

The purpose of this study was to evaluate the results of carinal resection for bronchogenic carcinoma in our institute. From 1981 to 1999, 24 carinal resection were performed for squamous cell carcinoma (n = 19), adenoid cystic carcinoma (n = 2), small cell carcinoma (n = 1), adenocarcinoma (n = 1), and mucoepidermoid carcinoma (n = 1). Nineteen underwent sleeve pneumonectomy, 2 had carinal resection without lung resection, 2 had carinal resection with right middle and lower lobectomy, and 1 had wedge pneumonectomy. In the patients with sleeve or wedge pneumonectomy, there were 5 operative death and 3 patients had survived for more than 3 years. Two patients with low-grade malignant tumors underwent carinal resection without lung resection and survived more than 10 years. We believe that limited carinal resection for low-grade malignant tumors are safe and valuable procedure. Careful selection of patients with sleeve or wedge pneumonectomy is mandatory.

Adult↗

[Patient compliance and the quality of life are well maintained in weekly paclitaxel and carboplatin therapy for advanced gynecologic cancers in Japanese women].

OBJECTIVES: To assess patient compliance and efficacy of a combination chemotherapy consisting of weekly administration of paclitaxel and carboplatin for gynecologic malignancy in Japanese women. METHODS: Fourteen ovarian and three uterine cancer patients received 80 mg/m2 of paclitaxel (paclitaxel) and AUC 1.5 to 2.0 of carboplatin weekly. The toxicity was evaluated and patients' QOL was tested. RESULTS: Neutropenia higher than grade 3 were observed in 29.4%. Four patients received G-CSF support. Grade 1 neurotoxicity was seen in 76.5% of patients. Evaluation of QOL by EORTC-QLQC30 showed significantly better tolerance of a weekly than monthly regimen. Three out of four patients with lung metastasis showed complete disappearance of the lesions. One patient with stage IIIb cervical cancer underwent postchemotherapy-hysterectomy and a complete pathological response was confirmed. The overall response rate was 64.7% including patients previously treated with platinum based multidrug regimens. CONCLUSIONS: A weekly paclitaxel and carboplatin regimen was well tolerated by Japanese women. The regimen was active in over 60% of cases and it also appeared active in multidrug resistant cases.

Aged↗

Curative resection of both primary and second primary lung cancer.

Curative resection of a second primary lung cancer in a patient who survived small-cell lung cancer is reported. Small-cell cancer had been treated with chemotherapy followed by surgical resection 12 years before. The patient developed squamous cell cancer as the second primary tumor and underwent lobectomy with mediastinal node dissection. Patients who undergo two curative pulmonary resections of both primary and second primary lung cancer are extremely rare. The patient is alive 176 months after the initial diagnosis of small-cell lung cancer and 28 months after resection for his second primary lung cancer. Careful follow-up at an interval of 3-6 months beyond 10 years is very important because adequate treatments could lead to longer survival of patients with primary small-cell lung cancer.

Carcinoma, Small Cell↗

[Early replacement of intravenous aminophylline administration with oral theophylline in treating acute exacerbation of asthma].

Intravenous (i.v.) administration of aminophylline has been used to relieve acute exacerbation of bronchial asthma for almost a century. Despite confidence in its effectiveness, controversy has arisen about its efficacy. We currently use aminophylline in the routine treatment of asthma since the drug is essentially useful. Continuous aminophylline infusion tends to be used rather haphazardly in hospital wards, and the criteria for termination of an infusion have not been clarified. We therefore attempted to determine: 1) whether continuous aminophylline infusion is actually beneficial, 2) whether the TDM (treatment drug monitoring) system can be used to establish a protocol for prescribed dosing after an early switch from i.v. to oral administration, and 3) whether adherence to the protocol would contribute to decreases in the duration of hospitalization and in medical expenses. Seventeen patients with acutely exacerbated asthma were enrolled in this study. Nine patients were prescribed oral theophylline on the second hospital day (p.o. group), while eight received continuous i.v. aminophylline (i.v. group). The serum theophylline concentrations were maintained in the therapeutic range in both groups. Peak flow, symptom scores, and QOL scores showed significant improvements in the p.o. group on the third hospital day. It might therefore be possible, by using the TDM system, to set the dosage of theophylline so that hospitalization is shortened.

Administration, Oral↗

Drop in plasma brain natriuretic peptide levels after successful direct current cardioversion in chronic atrial fibrillation.

BACKGROUND: According to previous reports, plasma atrial natriuretic peptide levels increase in atrial fibrillation (AF) and decrease after successful direct current (DC) cardioversion, but there have been no reports on plasma brain natriuretic peptide (BNP). OBJECTIVE: To determine whether plasma BNP levels decrease after successful direct DC cardioversion in patients with chronic AF. PATIENTS AND METHODS: Twenty patients who remained in sinus rhythm for at least seven days after cardioversion, and 20 normal control subjects, were studied. Group A consisted of 10 patients with underlying heart disease, including dilated cardiomyopathy (n=2), hypertrophic cardiomyopathy (n=1), mitral valve disease (n=3), hypertensive heart disease (n=3) and status after atrial septal closure (n=1). Group B consisted of 10 patients with just AF. Group C (serving as controls) comprised 20 subjects with normal sinus rhythm and no risk factors. RESULTS: Before cardioversion, plasma BNP levels were higher in group A (176.7+/-128.1 ng/mL) and in group B (96.8+/-51.7 ng/ml) than in group C (6.3+/-3.8 ng/ml) (P<0.01 for all). After successful cardioversion, mean plasma BNP levels in groups A and B decreased from 136.8+/-105.5 ng/mL to 46.4+/-44.2 ng/mL (P<0.01). In group A, plasma BNP levels decreased from 176.7+/-128.1 ng/mL to 62.5+/-54.6 ng/mL (P<0.01), and in group B, plasma BNP levels decreased from 96.8+/-51.7 ng/mL to 30.3+/-23.8 ng/mL (P<0.01). CONCLUSIONS: Lone AF raises plasma BNP levels, which is more marked if there is underlying structural heart disease present, and cardioversion reduces plasma BNP levels. Therefore, high plasma BNP levels in patients with chronic AF are likely to be caused by AF and reflect cardiac overloading associated with, although contributed to in part by, underlying heart diseases.

Adult↗

[From the perspective of the Japan Association of Clinical Reagents Industries].

Simple testing conducted in the hospital laboratory and the Commercial Lab is not considered "time-consuming testing" but prompt testing that enables obtaining data near the patient. In the field of medical care, the need for POCT(Point-of-Care Testing) which can test in prompt and minimally invasive ways has been increasing. In a related move, new techniques are being developing one after another to meet those needs. In the future, we will need to appropriately provide intensive service at the central laboratory and prompt service at the bedside while increasing economic efficiency. Because the 21st century is being promoted as the age of self-responsibility, we need to create systems and an environment for patients to manage their own health. In terms of the reduction of medical service fees, it seems that the method of payment directs forward like DRG definitely. Therefore, cooperation among industry and academia is needed to promote OTC test agents as testing before getting a disease and take an active part enlightening the importance of home testing. Currently, long-term medication is administered for an increasing number of chronic ailments going with the aging population. It seems desirable to develop and popularize easy home tests for monitoring chronic ailment and easy test agents for the checking side effects by drug.

Drug Industry↗

[The new portable system for home enteral nutrition, Portermate, made a patient possible go out for a long time: report of a case].

The patient, who is received home enteral nutrition (HEN) for a long time in a day, has problems on moving all days. Now, we tried Portermate, which is new portable devices for HEN, in his clinical care. The patient is chronic pancreatitis, and his clinical problems becomes to be worse after he ate. He was under total enteral nutrition via jejunostomy. His clinical complications were almost controlled after HEN, but he has a few complains receiving enteral nutrition. He would not move easily, for an old HEN system was not compact to move. Portermate made him go everywhere he wanted any time. It extremely improved his QOL under HEN. He continues to use Portermate.

Activities of Daily Living↗

Surgical management of early stage central (hilar) and peripheral nonsmall cell lung carcinoma.

BACKGROUND: To the authors' knowledge, the definitions of early lung carcinoma used in Japan are not yet approved internationally. In the current study the diagnostic methods, pathology, and results of the surgical treatment of early hilar and peripheral nonsmall cell lung carcinoma cases defined by Japanese criteria are presented. METHODS: Between 1977 and 1998, 43 patients with early hilar lung carcinoma were encountered. These patients constituted 14.5% of 200 hilar lung carcinoma patients who underwent resection during the same period. Between 1973 and 1998, there were 174 early peripheral lung carcinomas, which comprised 14.8% of 1173 peripheral lung carcinoma patients who underwent resection during the same period. RESULTS: The 5-year and 10-year survival rates of the early hilar lung carcinoma were 100% and 96.9%, respectively. The majority of the patients underwent bronchoplastic surgery, such as sleeve lobectomy and parenchymal-sparing surgery including seven sleeve segmentectomies and two second carinal resections. The effectiveness of the parenchymal-sparing resections was assessed by the conventional pulmonary function test as well as perfusion and ventilation scanning. There were 174 cases of peripheral early lung carcinoma among the 218 cases of peripheral lung carcinoma with tumor dimensions of < or = 2 cm. The cell types were 142 (81.6%) cases of adenocarcinoma, 18 (10.3%) cases of squamous cell carcinoma, and 14 (8%) cases of other cell types. These 174 patients comprised 14.8% of 1173 patients with peripheral nonsmall cell lung carcinoma who underwent surgery during the same period. The 5-year and 10-year survival rates for adenocarcinoma were 89.6% and 86.8%, respectively. The 5-year and 10-year survival rates for other cell types were both 71.8%. The overall 5-year and 10-year survival rates were 86.8% and 84.6%, respectively. CONCLUSIONS: Early lung carcinoma in both the hilar and peripheral regions, is curable if it is properly diagnosed and treated.

Aged↗

Crystal structure of N-acyl-D-glucosamine 2-epimerase from porcine kidney at 2.0 A resolution.

The X-ray crystallographic structure of N-acyl-d-glucosamine 2-epimerase (AGE) from porcine kidney, which has been identified to be a renin-binding protein (RnBP), was determined by the multiple isomorphous replacement method and refined at 2.0 A resolution with a final R-factor of 16.9 % for 15 to 2.0 A resolution data. The refined structure of AGE comprised 804 amino acid residues (one dimer) and 145 water molecules. The dimer of AGE had an asymmetric unit with approximate dimensions 46 Ax48 Ax96 A. The AGE monomer is composed of an alpha(6)/alpha(6)-barrel, the structure of which is found in glucoamylase and cellulase. One side of the AGE alpha(6)/alpha(6)-barrel structure comprises long loops containing five short beta-sheets, and contributes to the formation of a deep cleft shaped like a funnel. The putative active-site pocket and a possible binding site for the substrate N-acetyl-d-glucosamine (GlcNAc) were found in the cleft. The other side of the alpha(6)/alpha(6)-barrel comprises short loops and contributes to the dimer formation. At the dimer interface, which is composed of the short loops and alpha-helices of the subunits, five strong ion-pair interactions were observed, which play a major role in the dimer assembly. This completely ruled out the previously accepted hypothesis that the formation of the RnBP homodimer and RnBP-renin heterodimer requires the leucine zipper motif present in RnBP.

Animals↗

Constitutive regulation of cardiac fatty acid metabolism through peroxisome proliferator-activated receptor alpha associated with age-dependent cardiac toxicity.

The peroxisome proliferator-activated receptor alpha (PPARalpha) is a member of the nuclear receptor superfamily and mediates the biological effects of peroxisome proliferators. To determine the physiological role of PPARalpha in cardiac fatty acid metabolism, we examined the regulation of expression of cardiac fatty acid-metabolizing proteins using PPARalpha-null mice. The capacity for constitutive myocardial beta-oxidation of the medium and long chain fatty acids, octanoic acid and palmitic acid, was markedly reduced in the PPARalpha-null mice as compared with the wild-type mice, indicating that mitochondrial fatty acid catabolism is impaired in the absence of PPARalpha. In contrast, constitutive beta-oxidation of the very long chain fatty acid, lignoceric acid, did not differ between the mice, suggesting that the constitutive expression of enzymes involved in peroxisomal beta-oxidation is independent of PPARalpha(.) Indeed, PPARalpha-null mice had normal levels of the peroxisomal beta-oxidation enzymes except the D-type bifunctional protein. At least seven mitochondrial fatty acid-metabolizing enzymes were expressed at much lower levels in the PPARalpha-null mice, whereas other fatty acid-metabolizing enzymes were present at similar or slightly lower levels in the PPARalpha-null, as compared with wild-type mice. Additionally, lower constitutive mRNA expression levels of fatty acid transporters were found in the PPARalpha-null mice, suggesting a role for PPARalpha in fatty acid transport and catabolism. Indeed, in fatty acid metabolism experiments in vivo, myocardial uptake of iodophenyl 9-methylpentadecanoic acid and its conversion to 3-methylnonanoic acid were reduced in the PPARalpha-null mice. Interestingly, a decreased ATP concentration after exposure to stress, abnormal cristae of the mitochondria, abnormal caveolae, and fibrosis were observed only in the myocardium of the PPARalpha-null mice. These cardiac abnormalities appeared to proceed in an age-dependent manner. Taken together, the results presented here indicate that PPARalpha controls constitutive fatty acid oxidation, thus establishing a role for the receptor in cardiac fatty acid homeostasis. Furthermore, altered expression of fatty acid-metabolizing proteins seems to lead to myocardial damage and fibrosis, as inflammation and abnormal cell growth control can cause these conditions.

Aging↗