Development of a convenient and effective hypertension risk prediction model and exploration of the relationship between Serum Ferritin and Hypertension Risk: a study based on NHANES 2017-March 2020

Background

Hypertension is a major public health problem, and its resulting other cardiovascular diseases are the leading cause of death worldwide. In this study, we constructed a convenient and high-performance hypertension risk prediction model to assist in clinical diagnosis and explore other important influencing factors.

Methods

We included 8,073 people from NHANES (2017-March 2020), using their 120 features to form the original dataset. After data pre-processing, we removed several redundant features through LASSO regression and correlation analysis. Thirteen commonly used machine learning methods were used to construct prediction models, and then, the methods with better performance were coupled with recursive feature elimination to determine the optimal feature subset. After data balancing through SMOTE, we integrated these better-performing learners to construct a fusion model based for predicting hypertension risk on stacking strategy. In addition, to explore the relationship between serum ferritin and the risk of hypertension, we performed a univariate analysis and divided it into four level groups (Q1 to Q4) by quartiles, with the lowest level group (Q1) as the reference, and performed multiple logistic regression analysis and trend analysis.

Results

The optimal feature subsets were: age, BMI, waist, SBP, DBP, Cre, UACR, serum ferritin, HbA1C, and doctors recommend reducing salt intake. Compared to other machine learning models, the constructed fusion model showed better predictive performance with precision, accuracy, recall, F1 value and AUC of 0.871, 0.873, 0.871, 0.869 and 0.966, respectively. For the analysis of the relationship between serum ferritin and hypertension, after controlling for all co-variates, OR and 95% CI from Q2 to Q4, compared to Q1, were 1.396 (1.176-1.658), 1.499 (1.254-1.791), and 1.645 (1.360-1.989), respectively, with P < 0.01 and P for trend <0.001.

Conclusion

The hypertension risk prediction model developed in this study is efficient in predicting hypertension with only 10 low-cost and easily accessible features, which is cost-effective in assisting clinical diagnosis. We also found a trend correlation between serum ferritin levels and the risk of hypertension.

Preliminary results of the 105 GHz collective Thomson scattering system on HL-2A

A 105 GHz collective Thomson scattering (CTS) diagnostic has been successfully developed for fast-ion measurements on the HL-2A tokamak, and it has been deployed during an experimental campaign. Enhanced signals exhibiting synchronous modulation characteristics have been observed across all CTS channels upon the launch of a modulated probe wave. Results show that the intensity of the CTS signal increases with Neutral Beam Injection (NBI) power and is proportional to neutron count, indicating that the scattering signal contains a contribution from fast ions. Compared with the signal without NBI, the enhanced scattering spectrum due to NBI is slightly wider than the predicted fast ion range. Such broadening might be attributed to the heating effects of the gyrotron.

Plasma position measurements by O-mode and X-mode reflectometry systems in tokamak plasmas

Plasma Position Reflectometry (PPR) is planned to provide plasma position and shape information for plasma operation in future fusion reactors. Its primary function is to calibrate the drift of the magnetic signals due to the integral nature of magnetic measurement. Here, we attempt to measure plasma position using ordinary mode (O-mode) and extraordinary mode (X-mode) reflectometry systems on two tokamaks. A new physical model based on the phase shift is proposed to deduce the relative movement of the cut-off layer without density inversion. We demonstrate the plasma position measurements by absolute measurement from density profile inversion and relative measurement from phase shift. The combination of X-mode and O-mode reflectometers can minimize the limitations of single polarization reflectometry and further increase the accuracy of plasma position measurement. These results could provide an important technical basis for the further development of a real-time control system based on PPR.

[Self-reported quality of life in patients with coronary heart disease and analysis of the associated factors]

Objective: To investigate the quality of life and associated factors in patients with coronary heart disease (CHD) in China. Methods: A cross-sectional study of 25 provinces and cities in China was performed from June to September 2020. A questionnaire was used to collect the socio-demographic and clinical information of patients with CHD, while the European Five-dimensional Quality of Life Scale (EQ-5D) was used to assess the quality of life. Multiple linear regression model was performed to analyze the associated factors. Results: The median age of the 1 075 responders was 60 (52, 67) years, and 797 (74.1%) were men. The EQ-5D and EQ-VAS indices were 0.7 (0.5, 0.8) and 60.0 (40.0, 80.0). Among the five dimensions in the quality of life scale, the frequency of anxiety/depression was the highest (59.8%), while problems in self-care was the lowest (35.8%). In the multiple linear regression model, female, increasing age, obesity, comorbidity(ies), anxiety/depression, social media channels, and receiving the CABG therapy were associated with the lower EQ-5D index (all P<0.05). In addition, increasing age, obesity, comorbidity (ies), depression, anxiety and depression, social media channels, and receiving the CABG therapy were associated with lower EQ-VAS index (all P<0.05). Conclusion: Over half of the patients with CHD in China have a low quality of life, which is related to gender, age, obesity, treatment pathway, the presence or absence of comorbidity (ies), and psychological state. In addition to managing the adverse effects of traditional socio-demographic factors on the quality of life, clinical practices should pay attention to the psychological state of patients. Moreover, establishing a WeChat group for doctor-patient communication could improve the quality of life of CHD patients.

[Correlation between heart rate index, SBPpeak-to-SBPrest ratio and peak oxygen consumption in patients with chronic heart failure]

Objective: To investigate the correlation between heart rate index (HRI), systolic blood pressure(SBP) peak-to-SBPrest ratio (SBPR) and peak oxygen consumption (peakVO₂) in patients with chronic heart failure (CHF), and discuss the possibility of using HRI and SBPR collected during exercise to assess the exercise tolerance of CHF patients in the absence of gas analysis. Methods: In this cross-sectional study, a total of 547 patients with CHF who underwent cardiopulmonary exercise test(CPET) in Tongji Hospital Heart Rehabilitation Center Affiliated to Tongji University from March 2007 to December 2018 were collected retrospectively, focusing on their clinical data including age, gender, type of heart failure,BMI as well as data collected during their CPETs, such as peakVO₂, HRI and SBPR. Spearman univariate correlation analysis was used for statistical analysis, to unveil the correlations between peakVO₂ and those parameters, and multiple linear regression analysis was also conducted. Results: A total of 547 CHF patients conducting CPET were included in this research, of which 447 were male, at age of 63(56, 69). Univariate analysis indicates that HRI, SBPR and peakVO₂ showed significant positive correlation (r=0.323, 0.263, respectively, all P<0.001); Age and peak VO₂ showed significant negative correlation(r=-0.207, P<0.001); Male patients showed peakVO₂ higher than female(r=-0.229, P<0.001); PeakVO₂ of heart failure with reduced ejection fraction(HFrEF) was lower than heart failure with mid-range ejection fraction(HFmrEF)and heart failure with preserved ejection fraction(HFpEF) (r=0.181, P<0.001). Body mass index (BMI) had no significant correlation with peakVO₂ (P>0.05). Multivariate linear regression analysis showed that the HRI, SBPR were positively correlated with peakVO₂(t=7.68, 5.08, respectively, all P<0.05), while age and BMI showed negative correlation with peakVO₂(t=-5.43, -0.31, respectively, all P<0.05). PeakVO₂ of male was higher than female(t=-6.03, P<0.05), and peakVO₂ of HFrEF was lower than those of HFmrEF and HFpEF(t=3.17, 4.48, respectively, all P<0.05). A linear equation (F=33.52, adjusted R²=0.29) could be constructed: peakVO₂=10.65(male) or 8.53(female)+4.26HRI+3.31SBPR-0.07age-0.13BMI+0(HFrEF) or 1.05 (HFmrEF) or 1.62(HFpEF). Conclusion: HRI and SBPR are positively correlated with peakVO₂. In the absence of gas analysis, it is possible to apply HRI and SBPR during exercise to predict exercise tolerance in patients with CHF.

[Clinical significance of the deep learning algorithm based on contrast-enhanced CT in the differential diagnosis of gastric gastrointestinal stromal tumors with a diameter ≤ 5 cm]

Objective: Contrast-enhanced CT is an important method of preoperative diagnosis and evaluation for the malignant potential of gastric submucosal tumor (SMT). It has a high diagnostic accuracy rate in differentiating gastric gastrointestinal stromal tumor (GIST) with a diameter greater than 5 cm from gastric benign SMT. This study aimed to use deep learning algorithms to establish a diagnosis model (GISTNet) based on contrast-enhanced CT and evaluate its diagnostic value in distinguishing gastric GIST with a diameter ≤ 5 cm and other gastric SMT before surgery. Methods: A diagnostic test study was carried out. Clinicopathological data of 181 patients undergoing resection with postoperative pathological diagnosis of gastric SMT with a diameter ≤ 5 cm at Department of Gastrointestinal Surgery of Renji Hospital from September 2016 to April 2021 were retrospectively collected. After excluding 13 patients without preoperative CT or with poor CT imaging quality, a total of 168 patients were enrolled in this study, of whom, 107 were GIST while 61 were benign SMT (non-GIST), including 27 leiomyomas, 24 schwannomas, 6 heterotopic pancreas and 4 lipomas. Inclusion criteria were as follows: (1) gastric SMT was diagnosed by contrast-enhanced CT before surgery; (2) preoperative gastroscopic examination and biopsy showed no abnormal cells; (3) complete clinical and pathological data. Exclusion criteria were as follows: (1) patients received anti-tumor therapy before surgery; (2) without preoperative CT or with poor CT imaging quality due to any reason; (3) except GIST, other gastric malignant tumors were pathologically diagnosed after surgery. Based on the hold-out method, 148 patients were randomly selected as the training set and 20 patients as the test set of the GISTNet diagnosis model. After the GISTNet model was established, 5 indicators were used for evaluation in the test set, including sensitivity, specificity, positive predictive value, negative predictive value and the area under the receiver operating curve (AUC). Then GISTNet diagnosis model was compared with the GIST-risk scoring model based on traditional CT features. Besides, in order to compare the accuracy of the GISTNet diagnosis model and the imaging doctors in the diagnosis of gastric SMT imaging, 3 radiologists with 3, 9 and 19 years of work experience, respectively, blinded to clinical and pathological information, tested and judged the samples. The accuracy rate between the three doctors and the GISTNet model was compared. Results: The GISTNet model yielded an AUC of 0.900 (95% CI: 0.827-0.973) in the test set. When the threshold value was 0.345, the sensitivity specificity, positive and negative predictive values of the GISTNet diagnosis model was 100%, 67%, 75% and 100%, respectively. The accuracy rate of the GISTNet diagnosis model was better than that of the GIST-risk model and the manual readings from two radiologists with 3 years and 9 years of work experience (83% vs. 75%, 60%, 65%), and was close to the manual reading of the radiologist with 19 years of work experience (83% vs. 80%). Conclusion: The deep learning algorithm based on contrast-enhanced CT has favorable and reliable diagnostic accuracy in distinguishing gastric GIST with a diameter ≤ 5 cm and other gastric SMT before operation.

[Jiangsu Diabetic Eye Disease Study：epidemiological survey of blindness and moderate or severe visual impairment in people with type 2 diabetes over 50 years old in Funing County]

Objective: To investigate the prevalence, causes and risk factors of moderate or severe visual impairment and blindness in people with type 2 diabetes over 50 years old in Funing County, Yancheng. Methods: This is a cross-sectional study. Using cluster random sampling, 84 survey sites were selected, and eye examination was performed on people with type 2 diabetes over 50 years old who were registered with the chronic disease information center of Funing County Center for Disease Control and Prevention in Yancheng, Jiangsu. The prevalence of moderate or severe visual impairment and blindness were calculated by different ages and genders. The causes of blindness and visual impairment were determined, and their influencing factors were analyzed by univariate and multivarite logistic regression. Results: A total of 2 067 people were investigated in this study, and 1 909 people were included. The response rate was 92.4%. Based on PVA, the prevalence of blindness and moderate to severe visual impairment was 5.29% (95%CI: 4.29%-6.30%) and 18.54% (95%CI: 16.80%-20.29%). The prevalence of blindness was related to age, marital status, education, duration of diabetes, history of diabetic nephropathy, systolic blood pressure and nuclear opacity. The prevalence of moderate or severe visual impairment was related to age, gender, educational level, diabetes treatment, exercise, and glycated hemoglobin. The prevalence of blindness and moderate to severe visual impairment was 3.67% (95%CI: 2.82%-4.51%) and 9.80% (95%CI: 8.46%-11.13%) based on BCVA. The prevalence of blindness was related to age, marital status, education, duration of diabetes, history of diabetic nephropathy, exercise and systolic blood pressure, while the prevalence of moderate or severe visual impairment was related to age, educational level, diabetes treatment and nuclear opacity. The primary cause of blindness and visual impairment is cataract, followed by diabetic retinopathy. Conclusions: The prevalence of moderate or severe visual impairment and blindness in people with type 2 diabetes in Funing County is relatively high. Attention should be paid to the prevention of blindness in this population. (Chin J Ophthalmol, 2020, 56: 593-599).

[Seroepidemiological investigation of hepatitis C virus in Zhejiang Province: a hospital-based study]

Objective: To study serum HCV antibody (anti-HCV) with geographic distribution characteristics in Zhejiang Province. Methods: A stratified random cluster sampling method was used. Serum samples of the surveyed population were collected from selected hospitals, anti-HCV antibodies were examined, then hepatitis C infection rates among different genders, regions and age groups were analyzed. The anti-HCV rate was compared using the χ (2) test. Results: The average anti-HCV positive rate in Zhejiang Province was 0.24% [95% confidence interval (CI): 0.16% ~ 0.32%]. The antibody positive rate in the plain area was 0.32% (95% CI: 0.19% ~ 0.45%), which was significantly higher than the coastal islands 0.05%(95% CI: 0.00% ~ 0.12%, χ (2) = 7.638, P < 0.05). There was no significant difference between plain area and hilly area 0.22% (95% CI: 0.03% - 0.41%). There was no statistically significant difference in anti-HCV positive rates between males and females (χ (2) = 2.238, P = 0.135). The highest positive rate of anti-HCV (0.93%) was in the population aged 56-60 years and the lowest in the population aged less than 20 years. Anti-HCV positive rate of all age groups in 2017 was lower than that of 2006 seroepidemiological study of hepatitis C. Conclusion: Zhejiang Province is a region with low anti-HCV positive rate and the disease prevalence further reduced than 10 years ago. The positive rate of anti-HCV in plain areas is higher than islands. Middle-aged and elderly people are the age group with high prevalence, and the anti-HCV positive rate in people under 20 years old is exceptionally low. Gender differences in anti-HCV positive rate have little effect.

Comparative analysis of phylogenetic relationships, morphologies, and pathogenicities among Curvularia lunata isolates from maize in China

To understand the effects of disease-resistant maize varieties and new cropping systems on the population of Curvularia lunata, 52 isolates of C. lunata were collected in China from 2011 to 2013. The isolates were analyzed in terms of phylogenetic relationships, morphology, and pathogenicity. Phylogenetic analysis showed that the 52 isolates clustered into 2 distinct clusters with further subdivisions, suggesting the emergence of new genetic divergence within C. lunata. Results of morphology and pathogenicity analyses demonstrated that there were significant differences among these isolates: 27 isolates were classified as fast growing, 5 as slow growing, and 20 as moderate growing. Three isolates had white-colored colonies, 13 had yellowish green-colored colonies, and the remaining isolates had dark green-colored colonies. Furthermore, conidiation rates were assessed: 30 isolates were characterized as having low conidiation rates, 15 as having medium conidiation rates, and the remaining 7 isolates as having high conidiation rates. Eleven of the isolates appeared to be strongly pathogenic against maize, 15 isolates proved to be weakly pathogenic against maize, and the remaining isolates were regarded to be moderately pathogenic. Interestingly, correlation analysis demonstrated a negative correlation between the growth rate and the pathogenicity of the isolates, while a positive correlation was observed between the conidiation rate and the pathogenicity. No correlation was observed between the colony color and the pathogenicity of the isolates.

Expression profiling analysis of hypoxic pulmonary disease

Exposure of humans to low levels of environmental oxygen results in alveolar hypoxia and normally causes chronic pulmonary hypertension and morphological alterations of precapillary pulmonary vessels. In this study, the microarray dataset GSE11341 was used to identify potential differentially expressed genes related with human lung microvascular endothelial cell hypoxia. In addition, gene ontology term enrichment analysis was performed to explore their underlying functions. In addition, we also investigated the small molecules by comparing with the Connectivity Map. We found that hypoxia samples of 3, 24, and 48 h relative to 0 h displayed 22, 21, and 29 differentially expressed genes, respectively. Among them, six genes (ADM, HMOX1, VEGFA, EGLN3, APOLD1, and ANGPTL4) were closely related to pulmonary microvascular endothelial cell hypoxia response. Three drugs (pindolol, sulfapyridine, and ciclopirox) were selected as candidates to treat hypoxia-related pulmonary diseases. In conclusion, our results provide some underlying drug targets for treatment of hypoxic pulmonary patients.

One-dimensional single-crystalline bismuth oxide micro/nanoribbons: morphology-controlled synthesis and luminescent properties

Based on a facile vapor-phase transport method without any catalyst and template, one-dimensional single-crystalline bismuth oxide (Bi2O3) micro/nanoribbons were fabricated on silicon substrates in large quantities and morphology-controlled fabrication of Bi2O3 was achieved from a single precursor. The widths of Bi2O3 ribbons varied from 0.2 to 20 microm depending on the deposition temperatures. The thickness was in the range of 0.1-2 microm and the length reached several hundred micrometers and even millimeter range. The detailed composition and structural analysis confirmed the single-crystalline nature of alpha-Bi2O3 micro/nanoribbons with monoclinic structure. The photoluminescence spectrum of a single Bi2O3 ribbon showed a broadband emission from 450 to 750 nm in the visible region, consisting two peaks located at 589 and 697 nm which were primarily originated from the impurity ions and crystal defects. A self-catalyzed vapor-solid model was proposed to account for the growth mechanism of Bi2O3 ribbons with different morphologies.

Loss of heterozygosity at 6p21.3 underlying HLA class I downregulation in gastric cancer

Human major histocompatibility complex (HLA), located on 6p21.3, encodes for genes involved in antigen processing and presentation. Loss of heterozygosity (LOH) at 6p21.3 may cause downregulated expression of HLA, thus provide tumor cells with an immune-escape tumor phenotype. In the present study, we detected HLA class I expression in gastric cancer and correlated it with LOH at 6p21.3. The expression of HLA class I antigen was analyzed by immunohistochemical procedure in 50 fresh surgically removed gastric cancers and corresponding normal tissues using 5 monoclonal antibodies (mAbs). LOH studies were detected by using 6 microsatellite markers located at 6p21.3, 1 marker located at 6q21 and 2 microsatellite markers flanking the beta2m gene. HLA class I complex was obviously downregulated in gastric cancer compared with corresponding normal tissues (t=4.00, p<0.01). The expression of beta2m gene was also downregulated in tumor, but not concordant with HLA class I surface downregulation. Out of the 50 tumors, 25 (50%) showed LOH of at least one STR marker at 6p21.3 while only 11 (22%) showed LOH of the two markers flanking the beta2m gene. The LOH frequency of D6S105, which is close to HLA-A gene, was the highest in all STR markers studied (34%). Downregulation of HLA class I expression was correlated with loss of chromosomal regions at 6p21.3 (chi-squared = 5.13, p<0.05). Our results suggested that LOH of 6p21.3 contributed to HLA class I downregulated expression in gastric cancer especially at HLA-A locus. LOH of HLA-A gene might be one of the mechanisms underlying the abnormal expression of HLA class I complex.

Brain interleukin asymmetries and paw preference in mice

The two sides of the brain are differently involved in the modulation of immune responses as demonstrated by lesion and behavioral approaches. To study the interactions between cerebral cortex cytokines and brain lateralization, three groups of BALB/c mice were selected on the basis of their performance in the paw preference test (left-pawed, ambidextrous and right-pawed) and the levels of interleukin-1beta and interleukin-6 were measured in the two cerebral cortices after an intraperitoneal saline or lipopolysaccharide. Generally, right cortices had higher interleukin-1beta and interleukin-6 levels than left cortices for both saline and lipopolysaccharide-treated mice. A strong correlation between the levels of interleukin-1beta and interleukin-6 in right and left cortices and behavioral lateralization was observed. For the saline-treated mice: in their left cortices, interleukin-1beta levels were higher for ambidextrous mice than for right-pawed mice (P<0.05); in their right cortices, interleukin-6 levels were higher for ambidextrous mice than for right-/left-pawed mice, and right-pawed mice have higher levels of interleukin-6 than left-pawed mice (P<0.01). In their left cortices, interleukin-6 levels are higher for left-pawed mice than for both ambidextrous and right-pawed mice (P<0.01). In their left cortices, interleukin-6 levels are higher for left-pawed mice than for both ambidextrous and right-pawed mice (P<0.01). The quadratic curve equations showed that the levels of interleukin-1beta and interleukin-6 in the right/left cortices had a highly significant correlation with paw preference scores in both normal and lipopolysaccharide-treated mice. In conclusion, the present report demonstrated that the basal levels of interleukin-1beta and interleukin-6 were higher in the right cortex than left cortex in mice. There was a strong correlation between the levels of interleukin-1beta and interleukin-6 and behavioral lateralization, and cytokine asymmetries had a strong correlation with the direction and the intensity of behavioral lateralization.

Structure of human muscle creatine kinase

The crystal structure of human muscle creatine kinase has been determined by the molecular-replacement method and refined at 3.5A resolution. The structures of both the monomer and the dimer closely resemble those of the other known structures in the creatine kinase family. Two types of dimers, one with a non-crystallographic twofold symmetry axis and the other with a crystallographic twofold symmetry axis, were found to exist simultaneously in the crystal. These dimers form an infinite "double-helix"-like structure along an unusual long crystallographic 3(1) axis.

Structure of apo-glyceraldehyde-3-phosphate dehydrogenase from Palinurus versicolor

d-Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) shows cooperative properties for binding coenzymes. The structure of apo-GAPDH from Palinurus versicolor has been solved at 2.0 A resolution by X-ray crystallography. The final model gives a crystallographic R factor of 0.178 in the resolution range 8 to 2 A. The structural comparison with holo-GAPDH from the same species reveals a conformational change induced by coenzyme binding similar to that observed in Bacillus stearothermophilus GAPDH but to a lesser extent. The differences in magnitude during the apo-holo transition between these two enzymes were analyzed with respect to the change of the amino acid composition in the coenzyme binding pocket. In the crystalline state of apo-GAPDH, the overall structures of the subunits are similar to each other; however, significant differences in temperature factors and minor differences in domain rotation upon coenzyme binding were observed for different subunits. These structural features are discussed in relation to the environmental asymmetry of crystallographically independent subunits.

Magnetometry of evoked fields from human peripheral nerve, brachial plexus and primary somatosensory cortex using a liquid nitrogen cooled superconducting quantum interference device

Superconducting Quantum Interference Devices (SQUIDs) can be used to detect neuromagnetic fields evoked in the peripheral and central nervous system. Up to now, such measurements had to be based on SQUIDs with a low critical temperature (Tc) requiring liquid helium cooling. Recent improvements in high-Tc SQUID technology relying on liquid nitrogen cooling led to a significant reduction in the system's noise level. Hare, first high-Tc recordings of weak neuromagnetic fields are demonstrated. In particular, along the entire somatosensory afferent pathway including peripheral nerves, brachial plexus and primary somatosensory neocortex evoked neuromagnetic activities were detected using conventional recording parameters for bandwidth and number of averages. This opens up a wide perspective for cost-effective high-Tc magnetometry in clinical neuroscience.

[Tumor infiltrating lymphocytes inhibit spontaneous lung metastasis of LA795 adenocarcinoma in mice]

Tumor Infiltrating Lymphocytes (TILs) isolated from LA795 lung adenocarcinoma in mice have a remarkable antitumor activity, by using T739 syngeneic mice. TILs cytolytic activity in vitro is higher than that of LAK cells. TILs significantly inhibit spontaneous lung metastasis in vivo. The results in experiment I showed the following: TILs injection in tail vein, the inhibitory rate is 73.3%; TILs injection at tumor, 79.9%. The results in experiment II are similar to these in experiment I, and TILs antitumor activity in vivo is as three times as that of LAK cells.

[Pharmacological study on spleen-stomach warming and analgesic action of Cinnamomum cassia Presl]

This study deals with the antiulcer effect of water extract and ether extract of Cinnamomum cassia on four types of experimental gastric ulcer and with the antidiarrhea effect on two types of medicine-induced diarrhea in mice. These extracts have choleretic effect in anesthetized rats, and are analgesic as well. This is the pharmacologic basis of spleen-stomach warming and analgesic action of Cinnamomum cassia.

[Modulatory role of the cerebellar cortex during the classically conditioned nictitating membrane response in rabbit]

Classical conditioning of the rabbit nictitating membrane(NM) response was accomplished by standard delay procedure of paired tone (CS) and airpuff (US) stimuli. Upon reaching a criterion of 90% conditioned responses (CRs) in 3 consecutive blocks, an electrolytic lesion was made at the hemicerebellar VI cortical lobule on the training side. Results showed that the learned response of the dentate-interpositus (D-I) nuclei and the conditioned NM response were completely or almost completely eliminated without affecting the unconditioned response. However, cerebellar cortical lesion performed on animals being over 1 week overtrained produced no effect on CRs and the learned response of the D-I nuclei. Meanwhile, the spontaneous activity of the D-I nuclei during consolidation reduced in frequency as a result of the cortical lesion at the early stage of learning. Our findings indicate that the cerebellar cortex plays a modulatory role in the generation of the conditioned NM response and the development of the learned response of the D-I nuclei at an early stage of learning. With consolidation, the D-I nuclei become free of control from the cerebellar cortex and serve as the essential component of the memory trace for this model system.

[Antidiarrheal and anti-inflammatory effects of berberine]

Berberine sulfate (Ber) 40 and 80 mg/kg ig reduced the purging effects of castor oil or Cassia angustifolia leaf in mice, but did not affect the gastrointestinal transport function of Chinese ink in normal mice. Ber 60 mg/kg ig significantly inhibited the increased vascular permeability induced by ip 0.7% acetic acid in mice. Ber 20 and 50 mg/kg sc markedly inhibited the increased vascular permeability induced by histamine 100 micrograms/0.1 ml ic in rats. Ber 4 and 8 mg/kg sc produced obvious inhibition in the xylene-induced swelling of mouse ear. The anti-inflammatory effects were enhanced in a dose-dependent manner. It is suggested that the antidiarrheal effect of Ber is relative to its restriction against exudative inflammation to a certain extent.

A simple and rapid chemical method for the determination of cephalosporins

A simple and rapid chemical assay for cephalosporins is described. It is a simple modification of the colorimetric determination of penicillins in which the narrow spectrum beta-lactamase (penicillinase) is replaced by a broad spectrum beta-lactamase (cephalosporinase) produced by Enterobacter cloacae. The method can be used for assay of fermentation broths as well as for pure cephalosporins.

Enzymatic conversion of the unnatural tripeptide delta-(D-alpha-aminoadipyl)-L-cysteinyl-D-valine to beta-lactam antibiotics

Incubation of the unnatural tripeptide delta-(D-alpha-aminoadipyl)-L-cysteinyl-D-valine (DLD-ACV) with a partially purified extract of Cephalosporium acremonium resulted in the production of deacetoxycephalosporin C. The extract contained isopenicillin N synthetase (cyclase) and deacetoxycephalosporin C synthetase (expandase) but no penicillin epimerase activity, and was incubated aerobically in the presence of the components of the cyclase and expandase reaction mixtures (Fe++, ascorbate, dithiothreitol, alpha-ketoglutarate and ATP). The reaction was sensitive to penicillinase, indicating penicillin N to be an intermediate. However, when ring expansion was prevented by omission of alpha-ketoglutarate and ATP, no penicillin N was detected.

A pure enzyme catalyzing penicillin biosynthesis

Isopenicillin N synthetase (cyclase) has been purified to homogeneity from Cephalosporium acremonium strain C-10. The enzyme has a molecular weight of 40,000 to 42,000 and yields a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme was purified in 10 percent yield by a combination of protamine sulfate and ammonium sulfate precipitations, gel filtration, and ion-exchange high-performance liquid chromatography. The purified enzyme can be stabilized with sucrose and stored at -20 degrees C for several weeks without any loss in activity.

Repression of beta-lactam production in Cephalosporium acremonium by nitrogen sources

A variety of inorganic and organic nitrogen sources were added to fermentation media to determine their regulatory effects on the production of beta-lactam antibiotics by Cephalosporium acremonium. (NH4)2SO4 at concentrations higher than 100 mM (1.3%) strongly inhibited beta-lactam production. L-Asparagine and L-arginine proved to be the best nitrogen sources tested for beta-lactam production. The optimum concentration of asparagine was 1.2%. Higher concentrations led to NH3 accumulation, increase in pH, and lower growth rates. Addition of tribasic magnesium phosphate [Mg3(PO4)2 X 8H2O] to the (NH4)2SO4-containing medium stimulated beta-lactam production markedly and ammonium repression of the ring-expansion enzyme was reversed. It appears that the ring-expansion step is a very sensitive part of beta-lactam biosynthesis in C. acremonium with respect to nitrogen source repression. Other enzymes may also be sensitive in view of the fact that nitrogen source derepression not only led to increases in cephalosporin C but, to a lesser extent, penicillin N and total beta-lactam titers.

Studies on the ring-cyclization and ring-expansion enzymes of beta-lactam biosynthesis in Cephalosporium acremonium

Micrococcus luteus was found to be very sensitive to isopenicillin N and was used as assay organism for purification of the enzyme isopenicillin N synthetase, which cyclizes delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine to isopenicillin N. Purification of the enzyme from the crude extract obtained by sonication of mycelia of Cephalosporium acremonium CW-19 was carried out by ammonium sulfate precipitation, desalting with Sephadex G-25, gel filtration on LKB ultrogel AcA44 or ion-exchange chromatography on DEAE-Sepharose. The cyclization enzyme was separated from the ring-expansion enzyme and was purified considerably more than 50-fold by this procedure. Using the purified enzyme, we found that the disulfide bis-delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine required reduction to delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine in order to behave as a substrate. The enzyme activity was stimulated by FeSO4 and ascorbate, but other cofactors, including alpha-ketoglutarate, were inactive. In addition to delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine, the enzyme converted adipyl-L-cysteinyl-D-valine, N-acetyl-delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine, and glycyl-delta-(L-alpha-aminoadipyl)L-cysteinyl-D-valine to penicillins. All of these latter peptides were competitive inhibitors of the cyclization reaction. The Km of the cyclization enzyme is 10 times higher than that of the ring-expansion enzyme, deacetoxycephalosporin C synthetase. The pH and temperature optima of the two enzymes were rather similar. Phosphate inhibited ring expansion, but not cyclization. Both enzymes appear to be soluble enzymes of about 31 000 molecular weight.