Molecular-Sieving Separation of Methanol/Benzene Azeotrope by a Flexible Metal-Organic Framework

Separation of methanol/benzene azeotrope mixtures is very challenging not only by the conventional distillation technique but also by adsorbents. In this work, we design and synthesize a flexible Ca-based metal-organic framework MAF-58 consisting of cheap raw materials. MAF-58 shows selective methanol-induced pore-opening flexibility. Although the opened pores are large enough to accommodate benzene molecules, MAF-58 shows methanol/benzene molecular sieving with ultrahigh experimental selectivity, giving 5.1 mmol g-1 high-purity (99.99%+) methanol and 2.0 mmol g-1 high-purity (99.97%+) benzene in a single adsorption/desorption cycle. Computational simulations reveal that the preferentially adsorbed, coordinated methanol molecules act as the gating component to selectively block the diffusion of benzene, offering a new gating adsorption mechanism.

[Assessment of risk factors for bronchopulmonary dysplasia with pulmonary hypertension and construction of a prediction nomogram model]

Objective: To explore the risk factors of pulmonary hypertension (PH) in premature infants with bronchopulmonary dysplasia (BPD), and to establish a prediction model for early PH. Methods: This was a retrospective cohort study. Data of 777 BPD preterm infants with the gestational age of <32 weeks were collected from 7 collaborative units of the Su Xinyun Neonatal Perinatal Collaboration Network platform in Jiangsu Province from January 2019 to December 2022. The subjects were randomly divided into a training cohort and a validation cohort at a ratio of 8∶2 by computer, and non-parametric test or χ2 test was used to examine the differences between the two retrospective cohorts. Univariate Logistic regression and multivariate logistic regression analyses were used in the training cohort to screen the risk factors affecting the PH associated with BPD. A nomogram model was constructed based on the severity of BPD and its risk factors,which was internally validated by the Bootstrap method. Finally, the differential, calibration and clinical applicability of the prediction model were evaluated using the training and verification queues. Results: A total of 130 among the 777 preterm infants with BPD had PH, with an incidence of 16.7%, and the gestational age was 28.7 (27.7, 30.0) weeks, including 454 males (58.4%) and 323 females (41.6%). There were 622 preterm infants in the training cohort, including 105 preterm infants in the PH group. A total of 155 patients were enrolled in the verification cohort, including 25 patients in the PH group. Multivariate Logistic regression analysis revealed that low 5 min Apgar score (OR=0.87, 95%CI 0.76-0.99), cesarean section (OR=1.97, 95%CI 1.13-3.43), small for gestational age (OR=9.30, 95%CI 4.30-20.13), hemodynamically significant patent ductus arteriosus (hsPDA) (OR=4.49, 95%CI 2.58-7.80), late-onset sepsis (LOS) (OR=3.52, 95%CI 1.94-6.38), and ventilator-associated pneumonia (VAP) (OR=8.67, 95%CI 3.98-18.91) were all independent risk factors for PH (all P<0.05). The independent risk factors and the severity of BPD were combined to construct a nomogram map model. The area under the receiver operating characteristic (ROC) curve of the nomogram model in the training cohort and the validation cohort were 0.83 (95%CI 0.79-0.88) and 0.87 (95%CI 0.79-0.95), respectively, and the calibration curve was close to the ideal diagonal. Conclusions: Risk of PH with BPD increases in preterm infants with low 5 minute Apgar score, cesarean section, small for gestational age, hamodynamically significant patent ductus arteriosus, late-onset sepsis, and ventilator-associated pneumonia. This nomogram model serves as a useful tool for predicting the risk of PH with BPD in premature infants, which may facilitate individualized early intervention.

Heat-driven molecule gatekeepers in MOF membrane for record-high H2 selectivity

Hydrogen/carbon dioxide (H₂/CO₂) separation for sustainable energy is in desperate need of reliable membranes at high temperatures. Molecular sieve membranes take their nanopores to differentiate sizes between H₂ and CO₂ but have compromised at a marked loss of selectivity at high temperatures owing to diffusion activation of CO₂. We used molecule gatekeepers that were locked in the cavities of the metal-organic framework membrane to meet this challenge. Ab initio calculations and in situ characterizations demonstrate that the molecule gatekeepers make a notable move at high temperatures to dynamically reshape the sieving apertures as being extremely tight for CO₂ and restitute with cool conditions. The H₂/CO₂ selectivity was improved by an order of magnitude at 513 kelvin (K) relative to that at the ambient temperature.

Water-Stable Metal Azolate Frameworks Showing Interesting Flexibilities for Highly Effective Bioethanol Dehydration

The ethanol/water separation challenge highlights the adsorption capacity/selectivity trade-off problem. We show that the target guest can serve as a gating component of the host to block the undesired guest, giving molecular sieving effect for the adsorbent possessing large pores. Two hydrophilic/water-stable metal azolate frameworks were designed to compare the effects of gating and pore-opening flexibility. Large amounts (up to 28.7 mmol g-1) of ethanol with fuel-grade (99.5%+) and even higher purities (99.9999%+) can be produced in a single adsorption process from not only 95:5 but also 10:90 ethanol/water mixtures. More interestingly, the pore-opening adsorbent possessing large pore apertures showed not only high water adsorption capacity but also exceptionally high water/ethanol selectivity characteristic of molecular sieving. Computational simulations demonstrated the critical role of guest-anchoring aperture for the guest-dominated gating process.

[Myocardial biopsy of Liwen procedure: representability and etiological diagnostic value of cardiac samples obtained by a novel technique in patients with hypertrophic cardiomyopathy]

Objective: To investigate the representability and etiological diagnostic value of myocardium samples obtained from patients with hypertrophic cardiomyopathy (HCM) by transthoracic echocardiography-guided percutaneous intramyocardial septal biopsy (myocardial biopsy of Liwen procedure). Methods: This study was a retrospective case-series analysis. Patients with HCM, who underwent myocardial biopsy of Liwen procedure and radiofrequency ablation in Xijing Hospital, Air Force Military Medical University from July to December 2019, were included. Demographic data (age, sex), echocardiographic data and complications were collected through electronic medical record system. The histological and echocardiographic features, pathological characteristics of the biopsied myocardium of the patients were analyzed. Results: A total of 21 patients (aged (51.2±14.5) years and 13 males (61.9%)) were enrolled. The thickness of ventricular septum was (23.3±4.5)mm and the left ventricular outflow tract gradient was (78.8±42.6)mmHg (1 mmHg=0.133 kPa). Eight patients (38.1%) were complicated with hypertension, 1 patient (4.8%) had diabetes, and 2 patients (9.5%) had atrial fibrillation. Hematoxylin-eosin staining of myocardial samples of HCM patients before radiofrequency ablation evidenced myocytes hypertrophy, myocytes disarray, nuclear hyperchromatism, hypertrophy, atypia, coronary microvessel abnormalities, adipocyte infiltration, inflammatory cell infiltration, cytoplasmic vacuoles, lipofuscin deposition. Interstitial fibrosis and replacement fibrosis were detected in Masson stained biopsy samples. Hematoxylin-eosin staining of myocardial samples of HCM patients after radiofrequency ablation showed significantly reduced myocytes, cracked nuclear in myocytes, coagulative necrosis, border disappearance and nuclear fragmentation. Quantitative analysis of myocardial specimens of HCM patients before radiofrequency ablation showed that there were 9 cases (42.9%) with mild myocardial hypertrophy and 12 cases (57.1%) with severe myocardial hypertrophy. Mild, moderate and severe fibrosis were 5 (23.8%), 9 (42.9%) and 7 (33.3%), respectively. Six cases (28.6%) had myocytes disarray. There were 11 cases (52.4%) of coronary microvessel abnormalities, 4 cases (19.0%) of adipocyte infiltration, 2 cases (9.5%) of inflammatory cell infiltration,6 cases (28.5%) of cytoplasmic vacuole, 16 cases (76.2%) of lipofuscin deposition. The diameter of cardiac myocytes was (25.2±2.8)μm, and the percentage of collagen fiber area was 5.2%(3.0%, 14.6%). One patient had severe replacement fibrosis in the myocardium, with a fibrotic area of 67.0%. The rest of the patients had interstitial fibrosis. The myocardial specimens of 13 patients were examined by transmission electron microscopy. All showed increased myofibrils, and 9 cases had disorder of myofibrils. All patients had irregular shape of myocardial nucleus, partial depression, mild mitochondrial swelling, fracture and reduction of mitochondrial crest, and local aggregation of myofibrillary interfascicles. One patient had hypertrophy of cardiomyocytes, but the arrangement of muscle fibers was roughly normal. There were vacuoles in the cytoplasm, and Periodic acid-Schiff staining was positive. Transmission electron microscopy showed large range of glycogen deposition in the cytoplasm, with occasional double membrane surround, which was highly indicative of glycogen storage disease. No deposition of glycolipid substance in lysozyme was observed under transmission electron microscope in all myocardial specimens, which could basically eliminate Fabry disease. No apple green substance was found under polarized light after Congo red staining, which could basically exclude cardiac amyloidosis. Conclusion: Myocardium biopsied samples obtained by Liwen procedure of HCM patients are representative and helpful for the etiological diagnosis of HCM.

Single-crystal superprotonic conductivity in an interpenetrated hydrogen-bonded quadruplex framework

A proton-transporting pathway is crucial to the conduction mechanism in fuel cells and biological systems. Here, we report a novel 5-fold interpenetrated three-dimensional (3D) hydrogen-bonded quadruplex framework, which exhibits an ultrahigh single-crystal proton conductivity of 1.2(1) × 10^-2 S cm^-1 at 95 °C and 98% relative humidity, benefitting from the spiral H₃O⁺/H₂O chains in 1D pore channels studded with COOH/COO^- groups.

[Progress in diagnosis and treatment of rectal neuroendocrine neoplasms]

Neuroendocrine neoplasms (NENs) are relatively rare heterogeneous tumors that originate from peptidergic neurons and neuroendocrine cells and have been referred to as "carcinoids" in the past. Although this type of tumor had been previously considered to be indolent tumor with a low degree of malignancy, with the development of medicine and clinical study, researchers found that NENs had the potential to metastasize. They can occur in any part of the body where neuroendocrine cells are distributed and gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs) are the most common type of NENs.Due to the improvement of techniques such as endoscopy and imaging, the incidence of rectal neuroendocrine tumors(R-NENs) and the number of related clinical researches have both increased significantly in recent years. Although researches in Chinese and foreign medical centers are mostly retrospective studies of small samples and the efficacies of different treatment methods are still under debating and lack of sufficient medical evidence to support, the diagnosis and treatment of this disease is gradually becoming standardized according to the proposal of corresponding guidelines. The recent advances in the epidemiology, diagnosis and treatment of rectal neuroendocrine neoplasms are reviewed in this paper.

[Analysis of common gynecological diseases in 1142 married female workers]

Objective: To understand the prevalence of gynecologic diseases among married female workers. Methods: The data of married female workers who underwent occupational health examination in a physical examination center from January to December 2017 were collected. The relationship between the detection of common gynecological diseases, age and occupational types examined by gynecological routine, TCT, breast B-mode ultrasound, uterus and appendix B-mode ultrasound were analyzed. Results: Among the 1142 female workers, the total detection rate of reproductive tract infections was 67.25% (768/1142), the total detection rate of breast-related diseases was 75.22% (859/1142) ; the total detection rate of gynecological tumors and benign lesions was 14.71% (168/1142). The detection rate of breast hyperplasia was the highest 67.08% (766/1142), followed by vaginitis 51.66% (590/1142). Among the abnormalities detected in breast-related diseases, gynecological tumors and benign lesions, the highest detection rate was found in public institutions (85.66% and 27.13%), and the lowest was found in factory workers (70.24% and 7.89%). With the increase of age, the detection rate of breastrelated diseases (breast hyperplasia, breast cyst), gynecological tumors, benign lesions (uterine myoma), and Nessler's cyst abnormalities in married female workers increased (χ(2)(trend)=7.647、21.653、107.411、53.802, P<0.05), while the detection rate of columnar epithelium of cervix decreased (χ(2)(trend)=7.404, P<0.05). There was no significant difference in the total detection rate of reproductive tract infectious diseases (vaginitis, cervical polyps, cervical hypertrophy) among married famale workers of different ages (P<0.05) . Conclusion: The common gynecological diseases of married female workers are affected by many factors such as age and occupation. Health examination and health education should be carried out regularly to reduce the incidence of gynecological diseases among female workers according to different ages and occupations.

[Efficacy and safety of transthoracic echocardiography-guided percutaneous intramyocardial septal radiofrequency ablation for the treatment of patients with obstructive hypertrophic cardiomyopathy]

Objective: To investigate the safety and efficacy of transthoracic echocardiography-guided percutaneous intramyocardial septal radiofrequency ablation (PIMSRA) in patients with hypertrophic obstructive cardiomyopathy (HOCM). Methods: Nine HOCM patients with interventricular septal thickness ≥15 mm and ≤25 mm who were treated with PIMSRA between October 2016 to March 2017 in the Hypertrophic Cardiomyopathy Center of Xijing Hospital of Air Force Military Medical University were enrolled,and the clinical data were retrospectively analyzed.Interventricular septum thickness, left ventricular outflow tract diameter and maximum gradient were measured by transthoracic echocardiography immediately after procedure, at 1 month, 3 months and 6 months after operation.Symptoms and New York Heart Association (NYHA) functional class were assessed, and provoked left ventricular outflow tract gradient and exercise time were measured after 6 months. Results: The anterior interventricular septum ((21.5±2.6) mm vs. (24.7±2.7) mm, P<0.05) and posterior interventricular septum (21.1±2.5) mm vs. (22.6±3.3) mm, P<0.05) were significantly increased,left ventricular outflow tract diameter was widened ((8.2±3.4) mm vs. (4.8±2.2) mm, P<0.05), left ventricular outflow tract gradient ((26.8±19.6) mmHg (1 mmHg=0.133 kPa) vs. (83.3±32.4) mmHg, P<0.05) and mitral regurgitation (2.0±1.9) ml vs. (3.2±3.0) ml, P<0.05) were significantly decreased immediately after ablation compared with pre-operation values. Anterior interventricular septum, posterior interventricular septum and left ventricular outflow tract gradient further decreased after 1 month ((17.5±2.0) mm vs. (24.7±2.7) mm, P<0.05; (16.9±2.1) mm vs. (22.6±3.3) mm, P<0.05; (11.6±4.0) mmHg vs. (26.8±19.6) mmHg, P<0.05, respectively) compared with values immediately after ablation. Anterior interventricular septum and posterior interventricular septum decreased after 3 and 6 months ((14.8±1.7) mm and (13.4±2.0) mm vs. (17.5±2.0) mm, all P<0.05; (12.9±1.9) mm and (12.3±2.4) mm vs. (16.9±2.1) mm, all P<0.05, respectively) compared with values at 1 month after ablation.There were no significantly difference in left ventricular outflow tract gradient at 3 and 6 months post procedure compared with 1 month after ablation (all P>0.05). Compared with pre-operation, provoked left ventricular outflow tract gradient decreased ((25.5±11.4) mmHg vs. (147.8±58.0) mmHg, P<0.01), and total exercise time increased ((9.3±1.6) minutes vs. (6.7±1.6) minutes, P=0.03) at 6 months after operation.The symptoms were disappeared in 5 patients. There were 2 cases with NYHA class Ⅱ and 7 cases with NYHA class Ⅲ before operation,while there were 6 patients with NYHA classⅠ and 3 patients with NYHA class Ⅱ at 6 months after operation (P<0.01). Conclusion: Transthoracic echocardiography-guided PIMSRA is a safe and effective new treatment approach for patients with obstructive hypertrophic cardiomyopathy.

Effects of dietary Mn-methionine supplementation on the egg quality of laying hens

This study was conducted to investigate the effects of dietary manganese-methionine (Mn-Met) supplementation on the egg quality of laying hens. A total of 480 Jinghong-1 strain layers aged 53 wk were divided into 5 groups with 6 replicates of 16 layers. Birds in the control group were fed a diet supplemented with 60 mg Mn/kg in the form of MnSO4; the birds in other 4 experimental groups were fed a diet supplemented with 20, 40, 60, and 80 mg Mn/kg as Mn-Met, respectively. Dietary Mn-Met treatments significantly affected (P < 0.05) the albumen height, yolk color, and Haugh unit compared to those of the control diet. The Mn contents in the eggshell increased (P < 0.01) significantly by increasing the Mn-Met supplementation, whereas Mn content in eggshell was triple that in the yolk or albumen. Compared with the 60 mg/kg Mn-Met group, the transverse surface in the control group had (P < 0.01) a greater width of mammillary cones, and there were obvious cracks on the outer surface in the control. There was no difference (P > 0.05) in the eggshell gland (ESG) in the expression of calbindin-D28k (CaBP-D28k) mRNA in response to any diet treatment. In conclusion, dietary Mn-Met supplementation increased internal egg quality and the ultrastructure of the eggshell. Compared to the control, 60 mg/kg Mn-Met treatment resulted in improving egg quality, and 20 mg/kg Mn-Met treatment had similar effects the control treatment had on the egg quality. This indicates that the inorganic Mn can be replaced by the lower concentration of Mn-Met.

Effects of dietary L-arginine levels on small intestine protein turnover and the expression of genes related to protein synthesis and proteolysis of layers

The aim of this study was to test the effects of dietary L-arginine (Arg) levels on protein turnover in the small intestine and the expression of genes related to protein synthesis and proteolysis of laying hens. Xinyang Black commercial laying hens (n = 864, aged 217 d) were randomly distributed to 6 treatments with 4 replicates of 36 birds. The dietary treatments were corn-corn gluten meal based diets containing 0.64, 0.86, 1.03, 1.27, 1.42 and 1.66% L-Arg, respectively. Fractional protein synthesis rate (FSR) and fractional protein gain rate (FGR) in the jejunum were the highest in the 1.27% L-Arg group. The mRNA expression of target of rapamycin (TOR), ribosomal protein S6 kinase 1 (S6K1), and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) in the duodenum reached the highest in the 1.27% L-Arg group, while the mRNA expression of 20S proteasome (20S) was the lowest in the 1.27% L-Arg group. The mRNA abundances of TOR and S6K1 in the jejunum were the highest in the 1.27% L-Arg group, while the mRNA expression of 20S was the lowest in the 1.27% L-Arg group, and the protein expression and phosphorylation levels of TOR in the 1.27% L-Arg group were higher than those in the 0.64% L-Arg group. These results indicate that the action of an appropriate level of dietary L-Arg to improve the protein synthesis of the small intestine involves up-regulating the protein expression and phosphorylation level of TOR in the jejunum accompanied by inhibiting the mRNA expression of 20S of laying hens.

[Analysis of sonographic characteristics of thyroid nodules diagnosed as false positive or negative results in shear wave elastography]

Objective:In order to improve diagnostic accuracy, we study the characteristics of two dimensional ultrasound and shear wave elastography in the diagnosis of false negative or false positive thyroid nodules by shear wave elastography.Method:One hundred and eighty-nine nodules in 189 consecutive patients who had been determined by surgical operation and pathology. Conventional ultrasound features and SWE elasticity imaging characteristics and properties of the final postoperative pathology were recorded. A comparative study between true and false results of quantitative SWE elasticity imaging, and the corresponding conventional ultrasound nodule characteristics were compared.Result:Postoperative pathology showed 189 nodules, 74(39.2%) were benign and 115(60.8%) were malignant. The sensitivity, specificity of conventional ultrasound in the diagnosis of thyroid nodules were 56.5% and 81.1% respectively, and those of SWE were 60.9% and 85.1%. The false positive rate of shear wave elastography in diagnosing benign nodules and the false negative rate of malignant nodules were 14.9% and 39.1%, respectively. The false negative rate was higher than the false positive rate. A vertical growth (P< 0.01) and smaller diameter of the masses were significantly associated with false SWE findings (P< 0.01).Conclusion:The SWE imaging has important significance for differentiating benign and malignant thyroid nodules, but false results are inevitable, which requires clinicians conjunction with other test results to prevent errors judgment when reviewing the SWE imaging.

Effects of arsenic supplementation in feed on laying performance, arsenic retention of eggs and organs, biochemical indices and endocrine hormones

1. The primary objective of this experiment was to estimate the toxic effects of arsenic (As) supplementation in feed on laying performance, As retention by eggs and organs, serum biochemical indices and endocrine hormones in laying hens. 2. A total of 320 "Jinghong Number 1" hens, 56-week-old, were randomly allocated into four treatments of four replicates with 20 layers in each. Graded arsenical was added to the basal diet in the experimental diets at As levels of 0, 17, 34 and 51 mg/kg, respectively. The trial lasted for 9 weeks including 1 week for acclimatisation. 3. Supplementation of dietary As for eight weeks had no effect on laying performance. As retention in albumen, yolk, egg, liver and kidney increased as As levels increased The level of serum phosphorus (P) was minimised at the 17 mg As/kg group. The activity of serum glutamic oxaloacetic transaminase (GOT) increased linearly. No differences were observed for levels of serum calcium (Ca), alkaline phosphatase (AKP) and serum glutamic pyruvic transaminase (GPT). Concentrations of estradiol (E₂) and progesterone (PG) declined at 34 and 51 mg/kg As levels compared with the control group. As supplementation exerted no influence on levels of serum follicle stimulating hormone (FSH), luteinising hormone (LH), triiodothyronine (T₃), thyroxine (T₄) and the ratio between T₃ and T₄. 4. In conclusion, dietary As supplementation accelerated retention in tissues and eggs, and affected the laying rate by diminishing hormone levels of E2 and PG at 51 mg/kg.

CCAAT/enhancer-binding protein alpha antagonizes transcriptional activity of hypoxia-inducible factor 1 alpha with direct protein-protein interaction

Hypoxia-inducible factor 1 (HIF-1), a master heterodimeric transcriptional regulator consisting of HIF-1alpha and HIF-1beta subunits for cellular response to hypoxia, plays an important role in carcinogenesis, while CCAAT/enhancer-binding protein alpha (C/EBPalpha) is proposed to act as a tumor suppressor in C/EBPalpha-expressing tissues. Previously, we reported that ectopically expressed HIF-1alpha protein interacts with and enhances transcriptional activity of C/EBPalpha, which favors leukemic cell differentiation. Here we further showed that such an interaction also occurred in their endogenously expressing state of leukemic U937 cells. Glutathione S-transferase pull-down assay proposed that the protein-protein interaction was direct, and transactivation domains of C/EBPalpha and the basic helix-loop-helix domain of HIF-1alpha were essential for such an interaction. More intriguingly, we provided the first demonstration that C/EBPalpha competed with HIF-1beta for direct binding to HIF-1alpha protein. Correspondingly, C/EBPalpha overexpression significantly inhibited the DNA-binding ability of HIF-1 and expressions of hypoxia-responsive element-driven luciferase and HIF-1-targeted genes vascular endothelial growth factor, glucose transporter-1 and phosphoglycerate kinase 1. In parallel, suppression of C/EBPalpha expression by specific small hairpin RNA increased DNA-binding ability of HIF-1 and expression of these HIF-1-targeted genes in leukemic U937 cells. These results would provide new insights for antitumor potential of C/EBPalpha protein.

Analysis of the HFE gene (C282Y, H63D and S65C) mutations in a general Chinese Han population

Hereditary hemochromatosis (HH) is one of the most common autosomal recessive genetic disorders of iron metabolism in white populations, which leads to inappropriately high iron absorption. C282Y, H63D, and S65C are three major missense mutations of the hemochromatosis gene (HFE). In the present study, C282Y, H63D, and S65C mutations in 395 normal Chinese Han populations from Zhejiang province were investigated. No C282Y, S65C mutations, and H63D homozygote was observed, while the genotype frequency of H63D heterozygote was 4.6% and the allelic frequency 2.3% in this population. This was the first report to analyze the prevalence of C282Y, H63D, and S65C mutations in the HFE gene in a Chinese Han population. Low incidence of the HFE gene mutations could be a reason for the rarity of HH in the Chinese Han population studied.

14 bp deletion polymorphism in the HLA-G gene is a risk factor for idiopathic dilated cardiomyopathy in a Chinese Han population

Human leukocyte antigen (HLA) has been reported to be associated with the pathogenesis of autoimmune-associated idiopathic dilated cardiomyopathy (IDC). However, the HLA-G in this context is limited. In the current study, a total of 117 IDC patients and age and sex matched 401 unrelated healthy controls in a Chinese Han population were HLA-G genotyped for the 14 bp insertion and deletion polymorphism. IDC patients showed markedly increased frequencies of -14 bp/-14 bp genotype [Pc = 0.00049, odds ratio (OR) = 2.17] and -14 bp alleles (Pc = 4.1 x 10(-5), OR = 1.97) when compared with healthy controls. Whereas the frequencies of +14 bp/+14 bp genotype (Pc = 0.0036, OR = 0.35) and +14 bp alleles (Pc = 4.1 x 10(-5), OR = 0.51) were significantly lower in IDC. These data, for the first time, indicated that 14 bp insertion/deletion polymorphism in HLA-G gene could be a genetic risk factor for the susceptibility to IDC.

Physical and functional interaction of Runt-related protein 1 with hypoxia-inducible factor-1alpha

Angiogenesis and hematopoiesis are closely linked and interactive with each other, but few studies were given to identify possible links between angiogenesis-promoting proteins and hematopoiesis-related transcription factors. Here we investigated the potential relationship of oxygen-sensitive alpha-subunit of angiogenesis-related hypoxia-inducible factor-1alpha (HIF-1alpha) with Runt-related protein 1 (Runx1, also known as acute myeloid leukemia-1, AML-1), an important hematopoietic transcription factor. The results demonstrated that Runx1 and HIF-1alpha proteins directly interacted with each other to a degree, in which Runt homology domain of Runx1 was mainly involved. Leukemia-related abnormal Runx1 fusion protein AML1-ETO, which fuses the N-terminal 177 amino acid residues of the Runx1 protein in frame to ETO (eight-twenty-one) protein, also interacted with HIF-1alpha protein with greater ability than Runx1 itself. More intriguingly, Runx1 overexpression inhibited DNA-binding and transcriptional activity of HIF-1 protein with reduced expression of HIF-1-targeted genes such as vascular endothelial growth factor, while silence of Runx1 expression by specific small interfering RNA significantly increased transcriptional activity of HIF-1 protein, suggesting that Runx1 inhibited transcription-dependent function of HIF-1. Vice versa, HIF-1alpha increased DNA-binding ability and transcriptional activity of Runx1 protein. All these data would shed new insight to understanding Runx1 and HIF-1alpha-related hematopoietic cell differentiation and angiogenesis.

Association of the maternal 14-bp insertion polymorphism in the HLA-G gene in women with recurrent spontaneous abortions

Human leukocyte antigen (HLA)-G has been postulated as an important immunotolerant molecule in maintaining fetal-maternal relationship. Recent reports indicated that the 14-bp deletion/insertion polymorphism in exon 8 of HLA-G gene influences HLA-G mRNA stability and isoform splicing patterns, thus modulating the levels of HLA-G expression. This might play an immunomodulatory role of HLA-G during implantation and pregnancy. In the present study, 109 unrelated fertile control women and 79 women who had experienced recurrent spontaneous abortion (RSA) were genotyped for the 14-bp insertion/deletion polymorphism. No significant difference was observed in the distribution of 14-bp insertion/deletion genotype between controls and the RSA group. However, a greater number of 14-bp insertion alleles exist in the RSA group than in the controls.

Angiotensin stimulates the expression of interferon-inducible genes in H295R cells

Angiotensin-II (A-II) induces proliferation of zona glomerulosa cells and stimulates expression of cytochrome P-450 aldosterone synthase. The genes activated during this adrenal remodeling are not well defined. To clarify this mechanism, we sought to identify the genes whose expression is stimulated by A-II in the H295R cell line. Using a subtractive hybridization technique, we identified one clone whose expression was stimulated by A-II. The sequence of this gene was homologous to the human interferon-inducible genes, 9-27, 1-8D and 1-8U. The 5' portion of the gene was identical to the 1-8D gene product and the 3' was identical to the 9-27 gene product, but the existence of a transcript was not demonstrated by RT-PCR. The expression of these three genes was stimulated by A-II, with the 9-27 gene being most abundant. Potassium and forskolin also stimulated the expression of the 9-27 gene in the H295R cells, but not as effectively as did A-II or interferon-gamma.

[Expression of EGFR and PCNA, and DNA content in squamous cell carcinoma of larynx]

OBJECTIVE

To investigate the expression of epidermal growth factor (EGF), proliferating cell nuclear antigen (PCNA) and DNA index (DI) in laryngeal carcinoma, to analyse the correlation between these index and the biological characteristics of laryngeal carcinoma and their values of clinical prognosis.

METHOD

Immunohistochemical staining was used to detect the expression of EGFR and PCNA in laryngeal cancer and normal tissue, and with MIPS-I image analysis system DNA contents of cancer cell were measured and made out DNA index.

RESULT

The positive rate of EGFR in laryngeal carcinoma was 54.8%, and it was negative in all 10 normal laryngeal mucosa specimens (P < 0.01). The expression of EGFR did not correlate with histological grading and 5-years survival rate (P > 0.05), The positive expression of PCNA and DNA contents in the laryngeal carcinoma were increased with the decrease of tumorous differentiation (P < 0.05). With the increasing of PCNA positive expression and DI, the prognosis of the patients were poorer (P < 0.05).

CONCLUSION

EGFR may be related to the process of carcinogenesis in laryngeal carcinoma and was used as an early biomarker identifying premalignant lesions which had the greatest risk of carcinogenesis. PCNA and DI were simultaneously detected can be used as the prediction of tumor malignancy and prognosis.

An alternatively spliced rat mineralocorticoid receptor mRNA causing truncation of the steroid binding domain

We attempted to clone the putative 11-dehydrocorticosterone receptor by RT-PCR with two degenerate primers from highly homologous regions of the DNA and steroid binding domains of the receptor subfamily. In doing so, we have identified an alternatively spliced variant mRNA of the rat mineralocorticoid (MR) with a ten bp deletion in the C-terminal steroid binding domain. This deletion results in a truncated MR receptor of 807 amino acids in comparison to the wild type of 981 amino acids. The deletion variant was expressed in colon, kidney, heart, liver, aorta and brain tissues. The relative abundance of the deletion variant compared to the wild type MR was estimated to be 6% in rat kidney and 4% in hippocampus. This deletion was also detected in human kidney by RT-PCR. Site-directed mutagenesis was used to create the eukaryotic expression plasmid pCR3-rMRdel10 from the wild type for a transactivation assay using the luciferase reporter system in CV-1 cells. The deletion variant had the same baseline transactivation activity as the wild type MR, but did not respond to aldosterone or corticosterone stimulation. Co-transfection of MR with the deletion variant had no significant effect on transactivation activity of the MR, indicating that the deletion variant is unlikely to serve as a negative regulator of MR function.

Universal TA cloning

TA cloning is one of the simplest and most efficient methods for the cloning of PCR products. The procedure exploits the terminal transferase activity of certain thermophilic DNA polymerases, including Thermus aquaticus (Taq) polymerase. Taq polymerase has non-template dependent activity which preferentially adds a single adenosine to the 3'-ends of a double stranded DNA molecule, and thus most of the molecules PCR amplified by Taq polymerase possess single 3'-A overhangs. The use of a linearized "T-vector" which has single 3'-T overhangs on both ends allows direct, high-efficiency cloning of PCR products, facilitated by complementarity between the PCR product 3'-A overhangs and vector 3'-T overhangs. The TA cloning method can be easily modified so that the same T-vector can be used to clone any double-stranded DNA fragment, including PCR products amplified by any DNA polymerase, as well as all blunt- and sticky-ended DNA species. This technique is especially useful when compatible restriction sites are not available for the subcloning of DNA fragments from one vector to another. Directional cloning is made possible by appropriate hemi-phosphorylation of both the T-vectors and the inserts. With a single T-vector at hand, any DNA fragment can be cloned without compromising the cloning efficiency. The universal TA cloning method is thus both convenient and labor-saving.

Neutrophil inhibitory factor abrogates neutrophil adhesion by blockade of CD11a and CD11b beta(2) integrins

We studied the basis of inhibition of polymorphonuclear leukocyte (PMN) adhesion induced by neutrophil inhibitory factor (NIF), a 41-kDa CD11/CD18 beta(2) integrin-binding protein isolated from the canine hookworm (Ancylostoma caninum). NIF blocked PMN adhesion in a concentration-dependent manner with complete blockade occurring at approximately 10 nM NIF. Because CD11a and CD11b beta(2) integrins are functionally active on stimulated PMNs, and yet NIF is postulated to inhibit only CD11b integrin by binding to its I domain, we evaluated the contributions of CD11a and CD11b beta(2) integrins in the mechanism of inhibition of PMN adhesion to endothelial cells. We observed an additive inhibitory effect (>90% inhibition) of PMN adhesion to endothelial cells when NIF was used in combination with anti-CD11b monoclonal antibodies, which alone at saturating concentrations reduced PMN adhesion by only 50%. NIF also prevented aggregation of phorbol ester-stimulated JY lymphoblastoid cells that expressed only the functionally active CD11a, suggesting that NIF also can inhibit CD11a-dependent response. We transduced the NIF cDNA into human dermal microvessel endothelial cells in which NIF synthesis and release prevented PMN adhesion to the transduced human dermal microvessel endothelial cells. These data indicated that the potent antiadhesive effect of NIF may be the result of inhibition of CD11a and CD11b beta(2) integrins on PMNs. Moreover, the strategy of NIF release from transduced endothelial cells suggests the feasibility of blocking the CD11a- and CD11b beta(2) integrin-dependent PMN adhesion and PMN migration responses specifically at sites of endothelial cell activation.

[Study on the interaction between the 5' proximal region of mGAT-1 and nuclear proteins by the method of SPR]

The DNA fragment (named F182) corresponding the position of -1775(-)-1594 in the mouse GABA transporter 1 (mGAT-1) 5' proximal region was amplified by PCR. Then the DNA was immobilized to the surface of sensor chip SA5 via biotin-streptavidin linkage. The interaction between the F182 on SA5 and nuclear proteins from mouse liver and kidney was studied by the method of SPR with Biosensor of BIAcore-1000 respectively. The Binding between F182 and two nuclear proteins was definitely and specifically and both with the apparent dissociation rate of about 1.4E-5/s. Competitive experiment revealed that a conserved sequence within F182 had the main contribution to the binding event.

Requirement of Stat3 but not Stat1 activation for epidermal growth factor receptor- mediated cell growth In vitro

Stimulation of epidermal growth factor receptor (EGFR) by ligand(s) leads to activation of signaling molecules including Stat1 and Stat3, two members of the signal transducers and activators of transcription (STAT) protein family. Activation of Stat1 and Stat3 was constitutive in transformed squamous epithelial cells, which produce elevated levels of TGF-alpha, and was enhanced by the addition of exogenous TGF-alpha. Targeting of Stat3 using antisense oligonucleotides directed against the translation initiation site, resulted in significant growth inhibition. In addition, cells stably transfected with dominant negative mutant Stat3 constructs failed to proliferate in vitro. In contrast, targeting of Stat1 using either antisense or dominant-negative strategies had no effect on cell growth. Thus, TGF-alpha/EGFR-mediated autocrine growth of transformed epithelial cells is dependent on activation of Stat3 but not Stat1.

[Study on Trichosanthin induced apoptosis of leukemia K562 cells]

Trichosanthin (TCS), an eukaryotic ribosome-inactivating protein isolated from the root tuber of Trichosanthes plant, has various biological activities including abortion induction, antitumor, and anti-HIV. In this study, cultured human leukemia K562 cells treated with trichosanthin were examined. Analysis of the cells by single laser flow cytometry showed the sub-G1 peak. DNA extracted from these cells formed a characteristic "ladder" on agarose gel electrophoresis. Under electromicroscope, typical morphological changes of apoptosis were also observed. From all of these findings, we concluded that trichosanthin was able to induce apoptosis in K562 cells.

Myosin heavy chain isoform expression in rat smooth muscle development

Smooth muscle myosin heavy chains (MHCs), the motor proteins that power smooth muscle contraction, are produced by alternative splicing from a single gene. The smooth muscle MHC gene is capable of producing four isoforms by utilizing alternative splice sites located at the regions encoding the carboxy terminus and the junction of the 25- and 50-kDa tryptic peptides. These four isoforms, SM1A, SM1B, SM2A, and SM2B, are a combination of one of two heavy chains containing different carboxy-terminal tails (1 or 2) without (A) or with (B) an additional motif in the myosin head. In the present study, using RNA analysis and isoform-specific antibodies, we demonstrate the expression patterns of MHC isoforms during development in rat smooth muscle tissues. RNase protection analysis indicates that the mRNAs for SMA and SMB isoforms, which differ by a 21-nucleotide insertion in the region encoding the S1 head region of the myosin molecule, are differentially expressed during development in a highly tissue-specific manner. Smooth muscle MHC transcripts are first detectable in developing rat smooth muscle tissues at 17 days of fetal development. The SMB mRNA is shown to be expressed in smooth muscle from fetal bladder, intestine, and stomach and from neonatal aorta; however, it is not expressed in cultured smooth muscle cells from rat aorta. The SMA mRNA is also present at all stages of development in the smooth muscles examined; however, it is much less abundant than SMB mRNA in most fetal smooth muscles. We show here that the SMB isoform, which contains a unique seven-amino acid insertion at the junction of the 25- and 50-kDa tryptic peptides, is present in conjunction with SM1 and SM2 tails on immunoblots of smooth muscle from stomach, intestine, bladder, and uterus and is expressed during development in a pattern distinct from that of the SM1 and SM2 tail isoforms.

In vivo expression of neutrophil inhibitory factor via gene transfer prevents lipopolysaccharide-induced lung neutrophil infiltration and injury by a beta2 integrin-dependent mechanism

The binding of beta2 (CD18) integrins on PMN cell membrane to intercellular adhesion molecule (ICAM) counter-receptors on the surface of vascular endothelial cells mediates PMN adhesion to endothelial cells. Neutrophil inhibitory factor (NIF), a 41-kD glycoprotein isolated from the canine hookworm (Ancylostoma caninum), is a beta2 integrin antagonist that inhibits PMN adhesion to endothelial cells. We transferred the NIF gene into CD1 mouse lungs by intravenous injection of cationic liposomes to study the effects of in vivo NIF expression on LPS-induced lung PMN sequestration and the development of lung injury. RT-PCR and Northern blot analysis indicated the lung-selective expression of the NIF transgene, and immunocytochemistry showed prominent NIF expression in pulmonary microvessel endothelial cells. NIF staining was also observed in intraluminal leukocytes present in pulmonary microvessels. This may be the result of NIF binding to leukocytes after its secretion from the transduced lung cells, since there was no evidence of NIF gene expression in circulating leukocytes. Pulmonary vascular NIF expression abrogated the lung tissue PMN uptake and airspace migration of PMN and prevented lung vascular injury (as measured by the lung tissue uptake of [125I]labeled albumin) after the intraperitoneal LPS challenge (200 microg/mouse). Expression of a control protein, chloramphenicol acetyltransferase (CAT), by the same strategy, had no effect on these responses. In vitro studies showed that NIF prevented mouse PMN adhesion consistent with the inhibition of lung uptake after LPS challenge in NIF transgene-expressing mice. We conclude that pulmonary vascular expression of NIF, a specific beta2 integrin- binding protein, is a potentially useful gene transfer strategy in modulating the infiltration of PMN across the alveolar-capillary epithelial barrier and in preventing lung vascular endothelial injury.

Regulation of the 11 beta-hydroxysteroid dehydrogenase in the rat adrenal. Decrease enzymatic activity induced by ACTH

Patients with ectopic ACTH syndrome often develop hypertension and hypokalemic alkalosis with an abnormal increase in the ratio of plasma cortisol to cortisone, indicating that 11 beta-hydroxysteroid dehydrogenase (11 beta HSD) activity is inhibited. Inhibition of 11 beta HSD allows access of cortisol or corticosterone to the mineralocorticoid receptor where it act as a mineralocorticoid. Two isozymes, 11 beta HSD-1 and 11 beta HSD-2, have been cloned and characterized. The rat adrenal expresses the mRNAs for 11 beta HSD-2 and, in lesser amounts, 11 beta HSD-1. We investigated the effect of ACTH on the 11 11 beta HSD-2 activity in the rat adrenal. Rat adrenal cells zone fasciculata (ZF) were dispersed and incubated separately with increasing concentrations of ACTH for 90 min, and secretion of corticosterone (B) and 11-dehydrocorticosterone (A) in the media was measured by enzyme-linked immunoabsorbent assays (ELISA). The conversion of [3H]B to [3H]A in the presence of 0.5 mM NAD+ was evaluated in microsomes prepared from dispersed cells preincubated for 30 min with cyanoketone and metyrapone followed by incubation for 30 min with the same inhibitors, with and without 10 nM ACTH. The dispersed cells of the ZF produced significant amounts of A which increased with ACTH. The basal B/A ratio was 0.97 +/- 0.05. ACTH caused a concentration-dependent increase in the ratio of B/A with a maximum ratio of 9.58 +/- 0.20. ACTH also inhibited the conversion of [3H]B to [3H]A in microsomes in which endogenous B production was inhibited by cyanoketone and metyrapone. ACTH did not change the K(m) for B conversion, but the Vmax was reduced significantly (1.73 +/- 0.43 pmol/min. mg protein), indicating that ACTH suppressed the 11 beta HSD-2 in a noncompetitive fashion. Dibutyryl cyclic AMP (dcAMP) also produced a concentration-dependent increase in the B/A ratio, but various concentrations of calcium did not affect the enzyme activity. In summary, adrenal cells treated with ACTH results in a significant increase in the ratio of B/A in the ZF owing a noncompetitive inhibition of the 11 beta HSD-2 via the ACTH receptor.

Visualization of chromatin folding patterns in chicken erythrocytes by atomic force microscopy (AFM)

The organization of the higher order structure of chromatin in chicken erythrocytes has been examined with tapping-mode scanning force microscopy under conditions close to their native environment. Reproducible high-resolution AFM images of chromatin compaction at several levels can be demonstrated. An extended beads-on-astring (width of approximately 15-20 nm, height of approximately 2-3 nm for each individual nucleosome) can be consistently observed. Furthermore, superbeads (width of approximately 40 nm, height of approximately 7 nm) are demonstrated. Visualization of the solenoid conformation at the level of 30 nm chromatin fiber is attained either by using AFM or by using electron microscopy. In addition, tightly coiled chromatin fibers (approximately 50-60 nm and approximately 90-110 nm) can be revealed. Our data suggest that the chromatin in the interphase nucleus of chicken erythrocyte represents a high-order conformation and AFM provides useful high-resolution structural information concerning the folding pattern of interphase chromatin fibers.

Aldosterone biosynthesis in the rat brain

Messenger RNA (mRNA) for enzymes involved in adrenal steroid biosynthesis are expressed in the brain, and the coded enzymes have been shown to be active. The expression of mRNA for the cytochrome P-450 enzyme aldosterone synthase, crucial for the final step in the synthesis of aldosterone and the synthesis of aldosterone was studied in several anatomic areas of the rat brain. Expression of the mRNA for the aldosterone synthase was demonstrated by RT-PCR/Southern blot in adrenal, aorta, hypothalamus, hippocampus, amygdala, cerebrum, and cerebellum. Incubation of brain minces from intact and adrenalectomized rats demonstrated the synthesis of corticosterone and aldosterone from endogenous precursors. Incubations of brain minces with [1,2(3)H]-deoxycorticosterone, followed by extraction and three different successive TLCs, demonstrated the presence of labeled aldosterone, corticosterone, and 18-hydroxy-deoxycorticosterone. Incubation, in the presence of 10 microM cortisol or metyrapone, inhibited the synthesis of aldosterone or both aldosterone and corticosterone, respectively. These studies indicate that the rat brain has the enzymatic machinery for the synthesis of adrenal corticosteroids and is capable of synthesizing aldosterone. Aldosterone synthesized in the brain might play a paracrine role in the regulation of blood pressure.

Cloning of two alternatively spliced 21-hydroxylase CDNAs from rat adrenal

Interest in extra-adrenal corticosteroid synthesis has been revived by technological advances and the quest for answers to clinical problems. The cytochrome P450 21-hydroxylase converts progesterone to deoxycorticosterone, the obligatory substrate for the production of the main adrenal steroids aldosterone, cortisol and corticosterone. The rat P450 21-hydroxylase was cloned and two constructs, 21OH-5 and 21OH-6, sequenced. The constructs are similar, except that 21OH-6 has three additional major insertions of 64, 70 and 84 bp, a 3 bp deletion, and four extra base pairs immediately before the poly-A sequence. The entire coding region of 21OH-5 has 87 and 71% homology with the mouse and human 21-hydroxylase cDNA, respectively, whereas the encoded protein has 84 and 65% homology. Reverse transcriptase-polymerase chain reaction (RT-PCR) combined with Southern blot demonstrated expression of both transcripts in the kidney, aorta, liver, cerebellum, hypothalamus and brain stem, heart and cerebrum, but not the hippocampus, in addition to the adrenal. The entire coding region of 21OH-5 and the corresponding region of 21OH-6 including the three introns were cloned into pCR3 and the plasmids transiently transfected into COS-7 cells. Only 21OH-5 was translated into active protein, converting approximately 64% of 3H-progesterone to deoxycorticosterone in 2 h.

Inhibition of steroidogenesis in rat adrenal cells by 18-ethynyldeoxycorticosterone: evidence for an alternative pathway of aldosterone biosynthesis

The effect of the mechanism-based inhibitor 18-ethynyldeoxycorticosterone (18-E-DOC) on the late steps of the aldosterone biosynthetic pathway was examined in freshly isolated cells of the zona glomerulosa (ZG) and fasciculata (ZF) from rat adrenal glands. ZG synthesis of aldosterone was inhibited by 18-E-DOC in a time- and concentration-dependent manner with a Ki of approximately 0.05 microM. The maximal degree of inhibition of ZG production of aldosterone and 18-hydroxycorticosterone (18-OH-B) was approximately 80%. ZF cells, perhaps surprisingly, were found to secrete 18-OH-B at levels approximately one-third to one-fourth those of ZG cells and the Ki of 18-E-DOC inhibition of 18-OH-B secretion was approximately 10 microM for ZF cells, 200-fold higher than for ZG cells. The inhibitor had no effect on the secretion of corticosterone by either ZG or ZF, and the secretion of 18-hydroxydeoxycorticosterone (18-OH-DOC) by both the ZG and ZF was inhibited only to a minor degree. 18-E-DOC inhibited the biosynthesis of aldosterone by ZG cells incubated with 10 microM added DOC or 18-OH-DOC by approximately 75%, similar to the degree of inhibition of aldosterone biosynthesis from endogenous substrate, whereas ZF biosynthesis of 18-OH-B from either substrate was inhibited by less than 40%. ZF cells do not express aldosterone synthase, the only enzyme known to convert 18-OH-DOC into 18-OH-B. Incubation of MA-10 cells stably transfected with the cDNA of the rat aldosterone synthase with 18-E-DOC resulted in a complete inhibition of the conversion of DOC to aldosterone with a Ki of approximately 0.02 microM. In addition, transfected cells expressing 11beta-hydroxylase convert DOC to 18-OH-B in very small quantities only and cannot convert 18-OH-DOC to 18-OH-B. These data suggest that neither 11beta-hydroxylase nor aldosterone synthase are responsible for the biosynthesis of 18-OH-B by ZF cells from DOC or 18-OH-DOC, that 20% of aldosterone synthesis appears not to be attributable to the actions of aldosterone synthase and that an unknown CYP11B enzyme is also involved in the biosynthesis of 18-OH-B.

The sheep kidney contains a novel unidirectional, high affinity NADP(+)-dependent 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD-3)

The 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) enzymes convert corticosterone and cortisol to 11-dehydrocorticosterone and cortisone, and are thought to convey extrinsic specificity to the mineralocorticoid receptor by limiting access of the relatively more abundant glucocorticoids to it. Two different 11 beta-hydroxysteroid dehydrogenases (11 beta-HSD) have been described and cloned. The liver-type, NADP(+)-dependent 11 beta-HSD-1, has an affinity in the micromolar range and bidirectional activity. The NAD(+)-dependent 11 beta-HSD-2 has a higher affinity, in the nanomolar range, and exhibits only oxidase activity. 11 beta-HSD-2, because of its affinity and co-localization with the mineralocorticoid receptor, is likely to serve as the "gatekeeper" for the mineralocorticoid receptor in the kidney. Although the rat kidney expresses both isoforms, only the high-affinity, NAD(+)-dependent 11 beta-HSD-2 has been reported in the sheep kidney. We found both 11 beta-HSD NAD(+)- and NADP(+)-dependent activities in sheep kidney to be present. The NAD(+)-dependent activity exhibited a Km similar to that reported in the literature, 3.85 +/- 1.28 nM for corticosterone and 21.3 +/- 5.8 for cortisol, was distributed in approximately equal amounts between microsomes and nuclei, and was unidirectional, converting corticosterone to 11-dehydrocorticosterone. The enzyme exhibited prominent substrate inhibition. The NADP(+)-dependent activity had a Km for corticosterone of 4 +/- 1.3 nM for a Km for cortisol of 35.2 +/- 2 nM, 100-fold lower than that described for the 11 beta-HSD-1 in the liver of sheep and other species, and was more prevalent in the microsomes than the nuclei. This enzyme was not inhibited by its substrate. The NAD(+)-dependent activity was approximately 3-10 times greater than the NADP(+)-dependent activity when incubated with 5 nM corticosterone substrate, but had similar activity when incubated with 100 nM substrate concentrations. CHOP cells (a modified Chinese hamster ovary cell line) transiently transfected with the sheep 11 beta-HSD-2 plasmid exhibited a marked preference for NAD+ as co-factor. Oxidation of corticosterone by transfected cells in the presence of NADP+ was present, but minimal; NADP+ did not support the metabolism of cortisol, the primary glucocorticoid of sheep. These data suggest the existence of another NADP(+)-dependent enzyme, 11 beta-HSD-3, which, because of its high affinity and unidirectional oxidase activity, may play a physiological role in the modulation of glucocorticoid binding to both the mineralocorticoid and glucocorticoid receptors.

Effects of low-fat, high-carbohydrate diets on risk factors for ischemic heart disease in postmenopausal women

The effects of variations in dietary carbohydrate and fat on various aspects of carbohydrate and lipoprotein metabolism were evaluated in 10 healthy, postmenopausal women. The two diets were isoenergetic, assigned in random fashion, and consisted (as a % of total energy) of 15% protein, 60% carbohydrate, and 25% fat (60%-carbohydrate diet) or 15% protein, 40% carbohydrate, and 45% fat (40%-carbohydrate diet). Fasting plasma triacylglycerol, very-low-density-lipoprotein (VLDL) triacylglycerol, and VLDL-cholesterol concentrations were higher (P < 0.05-0.001) after the 60%-carbohydrate diet, whereas high-density-lipoprotein (HDL) cholesterol was lower (P < 0.05). Plasma insulin and triacylglycerol concentrations were also higher (P < 0.001) from 0800 to 0000 with the 60%-carbohydrate diet than with the 40%-carbohydrate diet. In addition, when vitamin A was given with the noon meal, the ensuing concentrations of retinyl palmitate were also higher after ingestion of the 60%-carbohydrate diet. Resistance to insulin-mediated glucose disposal, quantified at baseline by determining the steady state plasma glucose (SSPG) concentration at the end of a 180-min infusion of somatostatin, insulin, and glucose, correlated with the incremental increases in postprandial concentrations of plasma glucose (r = 0.68, P = 0.06), insulin (r = 0.82, P < 0.02), triacylglycerol (r = 0.77, P < 0.05), and retinyl palmitate (r = 0.68, P = 0.06) and with the Sf > 400 triacylglycerol (r = 0.77, P < 0.05), Sf 20-400 triacylglycerol (r = 0.72, P < 0.05), and Sf > 400 retinyl palmitate (r = 0.75, P < 0.01) lipoprotein fractions. Because all of these changes would increase risk of ischemic heart disease in postmenopausal women, it seems reasonable to question the wisdom of recommending that postmenopausal women consume low-fat, high-carbohydrate diets.

Corticosteroid synthesis in the central nervous system

The possibility that adrenocorticosteroids might be synthesized in the central nervous system was assessed by RT-PCR using primers for the CYP11B1 gene which codes for 11 beta-hydroxylase, the enzyme responsible for corticosterone and cortisol formation in the zona fasciculata, incubation of minces of several areas of the brain with 3H-DOC and measuring steroid metabolites, and determining the effect of the intracerebroventricular infusion of the 11 beta-hydroxylase mechanism-based inhibitor 19-ethynyldeoxycorticosterone upon the salt-induced increase in blood pressure in SS/jr rats. Significant, though small relative to the adrenal, amounts of mRNA for 11 beta-hydroxylase was found in the aorta, cerebrum, cerebellum, hippocampus, hypothalamus and amygdala, but not in the heart. Brain minces converted 3H-DOC to corticosterone and 11-dehydrocorticosterone to a greater degree than to 18-OH-DOC. The effect of 19-ethynyldeoxycorticosterone was dose dependent, with the lower doses preventing salt-induced hypertension and the higher doses having no effect or increasing the blood pressure.

High affinity NAD(+)-dependent 11 beta-hydroxysteroid dehydrogenase in the human heart

Receptor-ligand binding is an essential component of mineralocorticoid (MC) activity in target tissues. Detection of type 1 mineralocorticoid receptors (MR) in cardiac tissue is therefore suggestive that, like kidney, the heart is MC responsive. The presence of 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) within MC responsive tissue is essential to prevent saturation of MR by glucocorticoids. Using both high-performance liquid chromatography (HPLC) and thin layer chromatography (TLC), we have found that a high-affinity species of 11 beta-HSD predominates within human heart. Although two 11 beta-HSD isoforms were detected in human cardiac tissues, the activity of high-affinity (type 2) 11 beta-HSD was found to be at least twice that of low affinity (type 1) 11 beta-HSD. Human cardiac type 2 11 beta-HSD possesses characteristics identical to the high-affinity enzyme of distal renal tubules; 11 beta-dehydrogenation of corticosterone or cortisol to their 11-keto metabolites is NAD(+)-dependent and, with corticosterone as substrate, the enzyme has a nanomolar Km (15.1 nM as determined by Lineweaver-Burke analysis). Furthermore, its activity is unidirectional; corticosterone and cortisol are 11 beta-dehydrogenated to inactive 11-keto metabolites, whereas 11-oxoreductase activity (conversion of 11-dehydrocorticosterone and cortisone to corticosterone and cortisol, respectively) is absent. RT/PCR analysis, using primers complementary to the human renal type 2 11 beta-HSD sequence, demonstrated that the high-affinity species of 11 beta-HSD expressed in human heart is indeed the same enzyme as that produced in the kidney. These findings strongly suggest that, as is the case in the distal portion of the nephron, type 2 11 beta-HSD plays an important role in the human heart to promote glucocorticoid metabolism and to confer MC specificity upon MR.

Effect of variations in oral fat and carbohydrate load on postprandial lipemia

In this study we assessed the acute effects of the consumption of varying amounts of fat and fructose on the magnitude of postprandial lipemia. Subjects were studied after an overnight fast on four separate mornings, ingesting in random order 5, 40, or 80 g fat, or 5 g fat plus 50 g fructose. Vitamin A (36 mg, or 120,000 U retinol) was also given and blood was drawn at frequent intervals over the next 10 h for measurement of triacylglycerol and retinyl palmitate (RP) concentrations in plasma and the Sf > 400 and Sf 20-400 lipoprotein fractions. (Sf denotes flotation units.) In general, the postprandial triacylglycerol response increased in plasma and in both lipoprotein fractions as a function of both the baseline fasting triacylglycerol concentration and the amount of fat ingested. However, no matter how high the fasting plasma triacylglycerol concentration, there was no increase in the postprandial triacylglycerol concentration in plasma or either lipoprotein fraction after the 5-g oral fat load. The results of the measurements of RP concentration were somewhat similar in that there was a dose-dependent increase in the plasma and the Sf > 400 lipoprotein fraction in response to the higher fat loads. However, just the opposite was true in the Sf 20-400 lipoprotein fraction, for which the increase in RP concentration was inversely related to the size of the fat load.(ABSTRACT TRUNCATED AT 250 WORDS)

Cloning and expression of the rat adrenal cytochrome P-450 11B3 (CYP11B3) enzyme cDNA: preferential 18-hydroxylation over 11 beta-hydroxylation of DOC

The biosynthesis of glucocorticoids and mineralocorticoids in the rat adrenal cortex requires the action of two different cytochrome P450 11 beta-hydroxylases, CYP11B1 and CYP11B2, which are distributed in the zona fasciculata and glomerulosa, respectively. The existence of another cytochrome P450-11 beta gene, CYP11B3, was recently reported. Although CYP11B3 has similar gene structure and great homology to the CYP11B1 and -B2 genes, the CYP11B3 mRNA was not originally detected by reverse transcription-polymerase chain reaction (RT-PCR) and has only recently been cloned and detected from neonatal rat adrenals. Herein we demonstrate RT-PCR detection of CYP11B3 mRNA expressed in adult rat adrenal and brain tissues. The whole coding region of the CYP11B3 enzyme cDNA was cloned and sequenced. When transiently expressed in COS-7 cells the CYP11B3 converted deoxycorticosterone (DOC) to corticosterone and 18-hydroxydeoxycorticosterone, but not to 18-hydroxycorticosterone or aldosterone. It produced more 18-OH-DOC than corticosterone. A single mutation in CYP11B3 in which Gly-59 was replaced by Ser, reduced the enzymatic activity 5-6-fold. Furthermore, CYP11B3 mRNA expression is greater in neonatal, compared to adult rat adrenal glands.

Cloning, expression, and tissue distribution of the rat nicotinamide adenine dinucleotide-dependent 11 beta-hydroxysteroid dehydrogenase

A pcDNAI adult rat kidney complementary DNA (cDNA) library was screened using a sheep 11-hydroxysteroid dehydrogenase 2 (11 beta HSD-2) probe, and the isolated clones were sequenced. The 5'-end of the cDNA was determined by 5'-rapid amplification of cDNA ends. The rat 11 beta HSD-2 cDNA is 1864 base pair (bp) long. It consists of a 5'-untranslated region of 126 bp, an open reading frame of 1203 bp, and a 3'-untranslated region of 535 bp. The predicted protein contains 400 amino acid residues, with a calculated mol wt of 43,700. The rat 11 beta HSD-2 protein sequence is 85% homologous to human 11 beta HSD-2 and 76% to sheep 11 beta HSD-2. Expression of 11 beta HSD-2 messenger RNA by Northern blot and reverse transcription-polymerase chain reaction was high in kidney, distal colon, and adrenal and lower in the lung, hypothalamus, hippocampus, and midbrain. The rat 11 beta HSD-2 was transiently transfected into modified Chinese hamster ovary cells. Cells transfected with the 11 beta HSD-2 cDNA converted corticosterone into 11-dehydrocorticosterone. Conversion of corticosterone to 11-dehydrocorticosterone was NAD+ dependent and had a Km of 10.1 +/- 2.1 nM. In conclusion, we have cloned a rat NAD(+)-dependent 11 beta HSD with tissue distribution and kinetic characteristics suggesting that it could play a significant role in mineralocorticoid receptor selectivity.

[Intercellular relationship of notochord determination of Xenopus laevis]

During the process of determination, the presumptive notochord is situated beneath neuroepithelium, flanked at two sides by presumptive somites and underlain with archenteron roof ventrally. Among these neighbouring embryonic tissues, presumptive somites were found to exert the main influence on notochord determination. By electron microscopic observations, the presumptive notochord and somite cells were seen to situate either close to each other (plate I, Fig. 1) or connected by cytoplasmic processes forming intercellular lumen (plate I, Fig. 5). Coated pits and coated vesicles appeared at the outer surface of both types of cells (plate I, Figs. 1-4). For the presumptive somite cells, spherical bodies of different sizes and variable contents were observed either near or protruding from the outer surface (plate II, Figs. 6-10). The spherical bodies were also found in the intercellular lumen (plate III, Fig. 11). These spherical bodies were mainly composed of granules, loosely scattered or densely packed. The granules were of similar size and similar shade of electron staining as those of ribosomes of the presumptive somite cells. For the presumptive notochord cells, no spherical bodies of the above mentioned type were found, but phenomenon of engulfing luminal material was observed (plate III, Fig. 12). The significance of the appearance of these spherical bodies in the determination of notochord cells has been discussed.

Myosin heavy chain isoforms of human muscle after short-term spaceflight

The influence of microgravity on the myosin phenotype of skeletal muscle fibers in the vastus lateralis of eight crew members was studied before and after 5-day (n = 3) and 11-day (n = 5) spaceflights (space shuttle flights: STS-32, -33 and -34). Single-fiber electrophoresis analyses showed that the proportion of fibers expressing only slow (type I) myosin heavy chain (MHC) in the vastus lateralis was significantly lower after than before 11 days of spaceflight. Although the family of type II MHC isoforms was elevated post- compared with preflight, the distribution among the isoforms of type II MHC was not statistically different. Based on monoclonal and polyclonal antibodies specific for three adult MHC isoforms and single-fiber electrophoresis, approximately 3% of the fibers analyzed coexpressed all three adult MHC isoforms. The results from immunohistochemical staining with two different sets of antibodies indicate a reduction in the percentage of fibers expressing type I MHC as a result of spaceflight. The mean difference, however, was significant only when the fibers were categorized simply as type I or II. These changes appeared to be highly individualized among the astronauts. These results suggest that a rapid change in MHC isoform expression can occur in some muscle fibers after a relatively brief exposure to spaceflight.

Human fiber size and enzymatic properties after 5 and 11 days of spaceflight

Biopsies from the vastus lateralis muscle were obtained from three astronauts before and after two 5-day flights and from five astronauts before and after one 11-day flight (space shuttle flights: STS-32, -33, and -34). Muscle fibers from two separate samples from each biopsy were classified as type I and II or as type I, IIA, and IIB by using qualitative myofibrillar adenosinetriphosphatase (ATPase) staining. Cross-sectional area (CSA), number of capillaries per fiber, and the activities of succinate dehydrogenase (SDH), alpha-glycerophosphate dehydrogenase (GPD), and myofibrillar ATPase were determined from one sample of fibers of each myofibrillar ATPase type. Postflight biopsies had 6-8% fewer type I fibers than preflight. Mean fiber CSAs were 16-36% smaller after the 11-day flight with the relative effect being type IIB > IIA > I. Mean fiber CSAs were 11 and 24% smaller in type I and II fibers after 5 days of flight. Myofibrillar ATPase activities increased in type II but not in type I fibers after flight, whereas SDH activity was unaffected in either fast or slow fibers. GPD activity in type I fibers was approximately 80% higher (P > 0.05) postflight compared with preflight. Myofibrillar ATPase/SDH ratios in type II fibers were higher after than before flight, suggesting that some fast fibers were more susceptible to fatigue after flight. The GPD/SDH ratios were elevated in some type I fibers after spaceflight. The number of capillaries per fiber was 24% lower after than before flight, whereas the number of capillaries per unit CSA of muscle tissue was unchanged. These data suggest that adaptations in the size, metabolic properties, and vascularity of muscle fibers can occur rapidly in the space environment. These adaptations were qualitatively similar to those observed in animals after actual or simulated spaceflight conditions for short periods.

MRF4, Myf-5, and myogenin mRNAs in the adaptive responses of mature rat muscle

We studied the possible role of specific muscle regulatory factors (MRF) in the adaptive response to changes in contractile activity in mature skeletal muscle. The tibialis anterior muscle of anesthetized female rats was subjected to low-frequency stimulation, static stretch, or a combination of both. Message levels of MRF were observed after 2 h of activity, and the subsequent 20-h recovery period by slot blot and in situ hybridizations for MRF4, Myf-5, and myogenin. A combination of stimulation and stretch for 2 h increased MRF4 (11.6 +/- 5.3-fold) and Myf-5 (6.6 +/- 1.4-fold). In situ hybridization showed abundance in some regions of the muscle with positive staining near peripheral nuclei of both large and small fibers. Message levels remained high for 30 min and declined to near control levels by 20 h of recovery. Myogenin mRNA levels were unaffected by any manipulations. Neither stretch alone nor 10 Hz of electrical stimulation alone induced a significant increase in MRF. We conclude that myonuclei, and possibly activated myoblasts, increase expression of Myf-5 and MRF4 after a combination of both stimulation and stretch for 2 h.

Postprandial triglyceride and retinyl ester responses to oral fat: effects of fructose

It has been shown that addition of fructose to an oral fat load results in higher postprandial concentrations of triglyceride. The present study, performed in 11 healthy volunteers, was initiated to see whether the effect of fructose on fat-induced lipemia also involved changes in postprandial concentrations of triglyceride-rich lipoproteins of intestinal origin. Vitamin A was used to label intestinal lipoproteins, and the retinyl palmitate concentrations were determined in plasma and in the Sf > 400 and Sf 20-400 lipoprotein fractions (Sf denotes the Svedberg flotation index). Addition of fructose (50 g) to a standard (40-g oral) fat load resulted in higher postprandial concentrations of triglyceride and retinyl palmitate in plasma and the Sf > 400 lipoprotein fraction (P < 0.001, analysis of variance), and the higher the fasting plasma triglyceride concentration, the greater the magnitude of the fructose effect (r = 0.83, P < 0.002). These data show that triglyceride-rich lipoproteins of intestinal origin play a role in the fructose-induced accentuation of postprandial lipemia.

Relation between insulin resistance, hyperinsulinemia, postheparin plasma lipoprotein lipase activity, and postprandial lipemia

We examined the relation between insulin resistance, plasma glucose and insulin responses to meals, lipoprotein lipase (LPL) activity, and postprandial lipemia in a population of 37 healthy nondiabetic individuals. Plasma glucose and insulin concentrations were determined at frequent intervals from 8 AM through midnight (breakfast at 8 AM and lunch at noon); resistance to insulin-mediated glucose disposal was determined by measuring the steady-state plasma glucose (SSPG) concentration at the end of a 180-minute infusion of glucose, insulin, and somatostatin; LPL activity was quantified in postheparin plasma; and postprandial concentrations of triglyceride (TG)-rich lipoproteins were assessed by measuring the TG and retinyl palmitate content in plasma and the Svedberg flotation index (Sf) > 400 and Sf 20 to 400 lipoprotein fractions. Significant simple correlation coefficients were found between various estimates of postprandial lipemia and SSPG (r = .38 to .68), daylong insulin response (r = .37 to .58), daylong glucose response (r = .10 to .39), and LPL activity (r = -.08 to -.58). However, when multiple regression analysis was performed, only SSPG remained independently associated with both postprandial TG and retinyl palmitate concentrations. These data provide evidence that insulin resistance plays an important role in regulating the postprandial concentration of TG-rich lipoproteins, including those of intestinal origin.

Why do low-fat high-carbohydrate diets accentuate postprandial lipemia in patients with NIDDM?

OBJECTIVE

To understand why low-fat high-carbohydrate (CHO) diets lead to higher fasting and postprandial concentrations of triglyceride (TG)-rich lipoproteins in patients with non-insulin-dependent diabetes mellitus (NIDDM).

RESEARCH DESIGN AND METHODS

Patients with NIDDM were placed randomly on diets containing either 55% CHO, 30% fat, and 15% protein or 40% CHO, 45% fat, and 15% protein for 6 weeks, followed by crossover to the other diet. Test meals at the end of each diet period were consumed at 8:00 A.M. and 12:00 P.M. (noon) and contained 20 and 40% of daily calories, respectively. Vitamin A was also given at noon, and TG-rich lipoproteins of intestinal origin were identified by the presence of vitamin A esters. Frequent measurements were made throughout the 24-h study period of plasma glucose, insulin, and TG concentrations. Plasma samples obtained from 12:00 P.M. (noon) until 12 A.M. (midnight) were subjected to ultracentrifugation, and measurements were made of TG and vitamin A ester concentrations in plasma and in both the Svedberg flotation constant (Sf) > 400 (chylomicron) and Sf 20-400 (chylomicron remnant) lipoprotein fractions. In addition, very-low-density lipoprotein (VLDL)-TG turnover rate was estimated by following the decay of [3H]VLDL-TG. Finally, postheparin lipoprotein lipase and hepatic lipase activities were measured at the end of each dietary period.

RESULTS

Mean +/- SE hourly concentrations of glucose (8.0 +/- 0.8 vs. 7.5 +/- 0.7 mmol/l), insulin (184 +/- 26 vs. 158 +/- 19 pmol/l), and TG (2.8 +/- 0.2 vs. 2.1 +/- 0.2 mmol/l) were higher (P < 0.05-0.001) after the 55% CHO diet. The 55% CHO diet also led to an increase (P < 0.05-0.01) in the mean +/- SE hourly concentrations of vitamin A esters in plasma (2.3 +/- 0.3 vs. 1.6 +/- 0.1 mumol/l) and in both the chylomicron (2.0 +/- 0.3 vs. 1.4 +/- 0.1 mumol/l) and chylomicron remnant fractions (0.36 +/- 0.04 vs. 0.14 +/- 0.03 mumol/l). In addition, the VLDL-TG production rate was higher (17.2 +/- 1.4 vs. 12.8 +/- 1.0 mg.kg-1.h-1, P < 0.003) and the VLDL-TG fractional catabolic rate lower (0.22 +/- 0.02 to 0.28 +/- 0.02 l/h, P < 0.005) after the 55% CHO diet. Finally, there was an increase in lipoprotein lipase activity (7.0 +/- 0.8 to 8.1 +/- 0.7 mumol free fatty acids released .ml-1.h-1, P < 0.02) in response to the CHO-enriched diet.

CONCLUSIONS

A low-fat high-CHO diet in patients with NIDDM led to 1) higher day-long plasma glucose, insulin, and TG concentrations; 2) postprandial accumulation of TG-rich lipoproteins of intestinal origin; 3) increased production of VLDL-TG; and 4) increased postheparin lipoprotein lipase activity. These data provide a mechanism for the hypertriglyceridemic effect of CHO-enriched diets in patients with NIDDM and demonstrate that multiple risk factors for coronary heart disease are accentuated when these individuals consume diets recommended to reduce this risk.

Effect of metformin on postprandial lipemia in patients with fairly to poorly controlled NIDDM

OBJECTIVE

To quantify the effect of metformin on the metabolism of triglyceride (TG)-rich lipoprotein of intestinal origin in patients with non-insulin-dependent diabetes mellitus (NIDDM) who had responded to sulfonylurea but still had fasting hyperglycemia.

RESEARCH DESIGN AND METHODS

Sixteen patients with NIDDM who had demonstrated a fall in fasting plasma glucose concentration > 2.2 mmol/l in response to glipizide treatment but continued to have fasting plasma glucose concentrations > 8.3 mmol/l were studied. Fasting glucose, GHb, lipid and lipoprotein concentrations were determined, and resistance to insulin-mediated glucose disposal was estimated by measuring the steady-state plasma glucose (SSPG) concentration at the end of a 180-min infusion of somatostatin, glucose, and insulin. In addition, plasma glucose, insulin, and TG concentrations were measured at frequent intervals from 0800 to 2400, with patients eating breakfast at 0800 and lunch at 1200. Vitamin A was also given at lunch, and the retinyl ester content in plasma and in chylomicron (Svedberg flotation constant [Sf] > 400) and the chylomicron remnant (Sf 20-400) fractions were used to quantify the concentration of postprandial intestinal TG-rich lipoprotein from 1200 to 2400.

RESULTS

Fasting plasma glucose concentrations (6.8 +/- 0.4 vs. 10.5 +/- 0.4 mmol/l), GHb levels (7.9 +/- 0.3 vs. 10.8 +/- 0.5%), and day-long plasma glucose concentrations were all significantly lower after metformin treatment (P < 0.001), which was associated with a significant (P < 0.001) fall in SSPG concentration (11.0 +/- 0.9 to 9.6 +/- 0.6 mmol/l). In addition, postprandial concentrations of glucose, insulin, free fatty acids, and TG were lower (P < 0.001) following metformin treatment. Postprandial retinyl ester concentrations were also lower in plasma by 33 +/- 5.7% (P < 0.001) and in both the chylomicron (32 +/- 7.2%, P < 0.001) and chylomicron remnant (26 +/- 7.0%, P < 0.005) fractions.

CONCLUSIONS

Addition of metformin to sulfonylurea-treated patients with NIDDM with less than optimal glycemic control was associated with improved glycemic control, lower postprandial insulin and TG concentrations, and a decrease in postprandial concentration of TG-rich lipoproteins of intestinal origin. All of these changes might be expected to decrease risk of coronary heart disease.