[Diffusion tensor imaging in quantitative evaluation on thigh muscle of male amateur marathon runners after running a half marathon].

Objective: To investigate the effect of half marathon on thigh muscle in male amateur marathon runners by diffusion tensor imaging (DTI). Methods: A total of 17 male amateur marathon runners aged from 27 to 57 (43.7±2.8) years were recruited from May to August 2020 in Hangzhou, Zhejiang Province. MRI examination of bilateral thigh muscles were performed before and 3 h, 3 d and 7 d after a half marathon. The fractional anisotropy (FA) values was obtained by DTI sequence. The FA values of rectus femoris, intermedius femoris, medial femoris, lateral femoris, biceps femoris longus, semitendinosus, semimembranosus, adductor magnus and adductor longus were measured on the horizontal axis of bilateral thigh muscles. Friedman M test was used to compare the changes of FA values of each muscle at each time point before and after running, and pairwise comparison of FA values of statistically significant muscles at 3 h, 3 d and 7 d after running was performed. Results: The overall FA value of thigh muscle group [M (Q1, Q3)] at 3 h after running was decreased compared to before running [0.24 (0.20, 0.28) to 0.25 (0.21, 0.29), P<0.001], and there was no significant difference between baseline values at 3 d and 7 d after running (all P>0.05). FA values of vastus intermedius, vastus medialis, semimembranosus and adductor magnus at 3 h after running were lower than those before running [(0.19 (0.18, 0.22) vs 0.21 (0.19, 0.24), 0.19 (0.17, 0.20) vs 0.21 (0.18, 0.23), 0.26 (0.24), 0.29) vs 0.27 (0.15, 0.30) and 0.20 (0.19, 0.22) vs 0.21 (0.20, 0.23), both P<0.05], and there was no statistical significance between 3 d and 7 d after running and those before running (all P>0.05). FA value of vastus lateralis muscle at 3 h after running decreased compared with that before running, but the difference was not statistically significant (P>0.05). FA value began to increase at 7 d after running, and the difference was statistically significant [0.24 (0.21, 0.27) vs 0.23 (0.19, 0.25), P = 0.002]. FA value of rectus femoris muscle at 3 h after running decreased compared with that before running, but the difference was not statistically significant (P>0.05), and began to increase at 3 d after running and the difference was statistically significant [0.29 (0.26, 0.34) vs 0.26 (0.23, 0.29), P=0.006]. FA value of adductor longus muscle increased at 3 h after running, but the difference was not statistically significant (P>0.05). FA value continued to increase at 3 d and 7 d after running, and the difference was statistically significant [0.23 (0.21, 0.25) vs 0.22 (0.19, 0.24), 0.23 (0.21, 0.26) vs 0.22 (0.19, 0.24), all P<0.05]. Conclusions: The change of FA value of thigh muscle after half marathon is reversible. At 3 h after half marathon, FA values of femoris intermedius, femoris medialis, semimembranosus muscle and adductor magnus muscle of amateur marathon runners decreased most obviously, which may be the dominant muscle group during running.

[Legionnaires' disease with pronounced cerebellar involvement: case report and literature review].

Objective: To summarize the clinical course, neuroimaging and cerebrospinal fluid (CSF) analyses of cerebellar dysfunction in Legionnaires' disease. Methods: A case of Legionnaires' disease with pronounced cerebellar involvement was reported. The related literatures published up to February 2019 were reviewed with "Legionella, legionellosis, legionnaires' disease, cerebellum, cerebellar" as the keywords in CNKI, Wanfang and PubMed databases. Results: A 69-year-old man complained of anorexia and diarrhea for several days. He was subsequently admitted to the hospital after he had fever, ataxia, dysarthria and involuntary tremor. Chest CT revealed right lower lobe pneumonia. Routine urinalysis showed hematuria and proteinuria. Serum alanine transaminase was 52 U/L, creatinine 137 µmol/L, sodium 128 mmol/L, and creatine kinase 6 893 U/L. Cranial CT was normal. Analysis of CSF showed mildly elevated total protein. Legionella colonies isolated from bronchoalveolar lavage fluid was positive by PCR. After initial treatment with moxifloxacin and azithromycin for 7 days, the fever and neurological symptoms persisted. Corticosteroid therapy was administered for 3 days, the fever resolved, whereas the neurological symptoms improved gradually and slowly by 4 weeks of antibiotic therapy. Finally, successive serological test confirmed Legionella pneumophila serogroups 6 and 7 by indirect immunofluorescence. Twenty-one literatures with 23 cases were reviewed, and plus our case, there were a total of 24 cases for analysis. There were 16 males and 8 females, aged from 22 to 71 years. Ataxia and dysarthria were the cerebellar symptoms most frequently reported, occurring in 22 and 18 cases, respectively. All patients had various central and peripheral neuropathies during their illness. Neuroimaging and analysis of CSF was reported in 21 cases. There were no abnormalities in 18 cases of cranial imaging, 1 case with slight hydrocephalus on cranial CT, and 3 cases with hyperintensity in the splenium of corpus callosum on cranial MRI. Eighteen cases of CSF analyses were normal, whereas 1 case with elevated lymphocytes and 3 cases with elevated proteins. Nine cases were eventually identified as Legionella pneumophila serotype 1 by urinary antigen detection, 1 case as Legionella pneumophila serogroups 6 and 7, while the remaining 14 were unknown serotype. Long-term neurologic follow-up showed that 3 cases recovered completely in the first week, while 19 cases improved slowly in the following 3 weeks, and 13 cases had persistent deficits of gait or speech after 3 months. Conclusions: Legionellosis with cerebellar insufficiency is rare. It may be misdiagnosed in the onset of illness. After treatment, there is a trend of slow recovery and neurological symptoms may persist in long-term follow-up.

[Metabolomics analysis identifies serum glycerophospholipid expression: a comparison between men and women with asthma].

Objective: To determine whether asthma has a different metabolic glycerophospholipid profile in serum between women and men with asthma. Methods: Fifty-one outpatients with asthma (17 men, 34 women) were enrolled from Peking University Third Hospital from Jan 2015 to Dec 2015. Clinical data such as gender, age, body mass index, pulmonary function were recorded. Glycerophospholipid profile were measured in serum using liquid chromatography-mass spectrometry (LC-MS)-based metabolomics analysis. Projections to latent structures-discriminate analysis (PLS-DA) was used to compare the differences of glycerophospholipid level between men and women. Receiver Operating Characteristic (ROC) Curve was established from men and women. Results: Significantly different glycerophospholipid level were confirmed quantitatively between women and men. Levels of phosphatidylethanolamine (PE), phosphatidylcholine acetal phospholipid (PCP), lysophosphatidyl ethanolamine (LPE), alkyl phosphatidylethanolamine [PE(O)] were significantly higher in women relative to men [PE36: 2, PCP32: 1, LPE18: 0, and PE(O40: 7) was 0.050 (0.037, 0.079) vs 0.043 (0.000, 0.071), 0.057 (0.035, 0.727) vs 0.034 (0.000, 0.057), 0.233 (0.129, 0.390) vs 0.126 (0.075, 0.212), 0.007(0.000, 0.041) vs 0.000 (0.000, 0.000), respectively, all P<0.05). Levels of lysophosphatidylcholine (LPC), lysophosphatidylserine (LPS), and lysophosphatidylphosphatidylcholine [LPC(O)] were significantly lower in women compared to men [Levels of LPS22: 6, LPS20: 4, and LPS18: 1 were 0.000(0.000, 0.003) vs 0.009(0.000, 0.012), 0.015(0.010, 0.026) vs 0.047(0.022, 0.081), 0.008(0.003, 0.179) vs 0.020(0.008, 0.040), respectively, all P<0.05]. Area Under ROC Curve (AUC) of LPS (LPS20: 4) was 0.814. Conclusions: Glycerophospholipid levels in serum are significantly different between women and men asthmatic patients. LPS may contribute to gender based differences in asthmatics.

[Airway inflammation and small airway wall remodeling in neutrophilic asthma].

OBJECTIVE: To investigate the distribution of airway inflammation phenotype in patients with bronchial asthma (asthma), and to analyze clinical characteristics, inflammatory cytokines, pulmonary small vessels remodeling and small airway wall remodeling in patients with neutrophilic asthma. METHODS: Sixty-three patients with asthma were enrolled from January 2015 to December 2015 in Peking University Third Hospital. Clinical data including gender, age, body mass index (BMI), pulmonary function tests (PFTs), asthma control test (ACT) were recorded. All the patients underwent sputum induction. The cellular composition of the sputum was evaluatedand the concentration of active MMP-9 in the sputum tested. Blood routine tests were done and the concentration of IgE, periostin, and TGF-beta1 levels were measured in serum by enzyme-linked immunosorbent assay (ELISA). Small airway wall remodeling was measured in computed tomography (CT) scans, as the luminal diameter, luminal area, wall thickness and wall area % adjusted by body surface area (BSA) at the end of the 6th generation airway, in which the inner diameter was less than 2 mm. Small vascular alterations were measured by cross-sectional area (CSA), and the total vessel CSA < 5 mm2 was calculated using imaging software. RESULTS: The distributions of airway inflammatory phenotypes of the asthmatic patients were as follows: neutrophilic asthma (34.9%, 22/63), eosinophilic asthma (34.9%, 22/63), mixed granulocytic asthma (23.8%, 15/63), and paucigranulocytic asthma (6.3%, 4/63). The neutrophilic subtype patients had a significantly higher active MMP-9 level in sputum compared with the eosinophilic phenotypepatuents, as 179.1 (74.3, 395.5) vs. 50.5 (9.7, 225.8), P<0.05. Sputum neutrophil count was negatively correlated with FEV1%pred (r=-0.304,P<0.05), and positively correlated with active MMP-9 level in sputum (r=-0.304, P<0.05), and positive correlation trend with airway wall thickness (r=0.533, P=0.06). There was a significantly negative correlation of active MMP-9 level in sputum with FEV1%pred (r=-0.281, P<0.05), in positive correlation with small airway wall area (%)(r=0.612, P<0.05), and inpositive correlation trend with airway wall thickness (r=0.612, P=0.06). Neutrophils count in peripheral blood was positively correlated with neutrophil counts in sputum. CONCLUSION: Neutrophil count in airway is related to lung function in asthmatic patients. Neutrophils may accelerate small airway wall remodeling through the release of active MMP-9. Neutrophil count in peripheral blood is related to neutrophils count in sputum, which may be used as a substitute for evaluating inflammatory phenotype.

[Bronchial adenoid cystic carcinoma masquerading as bronchial asthma: a case report].

Here we reported a case of bronchial adenoid cystic carcinoma from Peking University Third Hospital. A 40-year-old female presented with dry cough for 1 year and nocturnal paroxysmal attacks of wheezing for 4 months. She was a non-smoker, and did not have past histories of asthma or allergy. On physical examination, no stridor, wheezing and cyanosis were present and the general appearance was good. The results of the laboratory analysis, including blood eosinophils count, immunoglobulin E level and chest X-ray were normal. Spirometry revealed reversible airflow obstruction, and post-bronchodilator forced expiratory volume in one second (FEV1) showed an increase of 12% and 230 mL from baseline. Bronchial asthma was diagnosed, however, she responded poorly despite the adequate anti-asthma therapy including high dose inhaled corticosteroid plus long-acting beta2-agonist, theophylline and montelukast. Then chest computed tomography (CT) was performed which showed a polypoid mass occupying the lumen of left main bronchus. Then the bronchoscopy revealed a polypoid endo-bronchial mass arising from the left main bronchus, causing subtotal obstruction of the lumen. Biopsy was carried out through the bronchoscopy, the pathological findings showed characteristic cribriform and tubular pattern which was formed by two-layered cells with ductal and myoepithelial phenotypes, which were consistent with adenoid cystic carcinoma. Re-examining the patient, the lung was clear without any wheeze when she was seated. However, inspiratory wheeze was heard in her left upper lung when she was supine, and disappeared after sitting up again. Subsequently the patient underwent a resection surgery. At the operational site, the tumor was seen on the anterolateral wall of the left main bronchus, without submucosally expanding histologically. Therefore, a sleeve resection surgery of the left main bronchus was performed. Following surgery, chest CT scan revealed complete resolution of the tumor. Her symptoms improved significantly, as did her pulmonary function tests, although all the medicines for asthma were stopped. Now, two years after the operation, the patient remained asymptomatic, and spirometry was performed again which showed normal completely. The presenting case report emphasizes the fact that not all wheezes and reversible airflow obstruction are asthma. It is critical to bear in mind that if a "difficult asthma" patient does not respond to appropriate anti-asthma therapy; localized obstructions should be differentiated.

Identification and functional characterization of microRNAs reveal a potential role in gastric cancer progression.

PURPOSE: To investigate the potential candidate microRNA (miRNA) biomarkers for the clinical diagnosis, classification, and prognosis of gastric cancer (GC). METHODS: We use bioinformatics overlapping subclasses analysis to find the tumor grade and lymphatic metastasis-related GC specific miRNAs from the Cancer Genome Atlas (TCGA) database. Then, we further investigated these GC specific miRNAs distributions in different GC clinical features and their correlations overall survival on the basis of GC patients' information and their related RNA sequencing profile from TCGA. Finally, we randomly selected some of key miRNAs use qRT-PCR to confirm the reliability and validity. RESULTS: 22 GC specific key miRNAs were identified (Fold-change >2, P < 0.05), 11 of them were discriminatively expressed with tumor size, grade, TNM stage and lymphatic metastasis (P < 0.05). In addition, nine miRNAs (miR-196b-5p, miR-135b-5p, miR-183-5p, miR-182-5p, miR-133a-3p, miR-486-5p, miR-144-5p, miR-129-5p and miR-145-5p) were found to be significantly associated with overall survival (log-rank P < 0.05). Finally, four key miRNAs (miR-183-5p, miR-486-5p, miR-30c-2-3p and miR-133a-3p) were randomly selected to validation and their expression levels in 53 newly diagnosed GC patients by qRT-PCR. Results showed that the fold-changes between TCGA and qRT-PCR were 100 % in agreement. We also found miR-183-5p and miR-486-5p were significantly correlated with tumor TNM stage (P < 0.05), and miR-30c-2-3p and miR-133a-3p were associated with tumor differentiation degree and lymph-node metastasis (P < 0.05). These verified miRNAs clinically relevant, and the bioinformatics analysis results were almost the same. CONCLUSION: These key miRNAs may functions as potential candidate biomarkers for the clinical diagnosis, classification and prognosis for GC.

[The clinical significance of increased neutrophils in bronchoalveolar lavage fluid in sarcoidosis].

Objective: To investigate the clinical implications of increased neutrophils in bronchoalveolar lavage fluid (BALF) in sarcoidosis. Methods: A retrospective analysis was performed for 72 cases of histologically diagnosed, treatment-näive sarcoidosis admitted to Peking University Third Hospital from January 2000 to October 2014. The patients included 18 men and 54 women, 26 to 75 years of age [(50±10) years], with the disease course 0.5 month to 12 years (median disease course, 3 months). Results of cell count and differentials of BALF were analyzed and the patients were grouped based on the percentage of neutrophils: those with increased neutrophils (>3%) and those without (≤3%). Clinical manifestations, pulmonary function tests, radiological features, bronchoscopic findings, and other laboratory data were compared between the 2 groups. Finally 67 patients were followed for 6 to 240 months (median 36 months). The subsequent changes of radiological manifestations and relapses after therapy were recorded and compared. Results: There were 72 patients in the study, including 16 with increased BALF neutrophils(stage Ⅰ/Ⅱ/Ⅲ, 4/10/2) and 56 without(stage Ⅰ/Ⅱ/Ⅲ, 9/45/2). Compared with patients without increased neutrophils, those with increased neutrophils had more reticular changes in the lungs(6/16, 8/56), more common diffusion dysfunction (7/13, 11/46) with lower DLCO% [(70±19)% vs (89±23)%], higher percentage of CD8＋ lymphocytes [(19±4)% vs (11±4)%, P<0.05] in BALF. Sixteen (stage Ⅰ/Ⅱ/Ⅲ, 4/10/2) and 51 (stage Ⅰ/Ⅱ/Ⅲ, 9/41/1) patients with and without increased neutrophils were followed respectively. Compared with patients without increased neutrophils, those with increased neutrophils tended to deteriorate and relapse despite corticosteroid therapy. Conclusions: Sarcoidosis patients with BALF neutrophilia had more severe pulmonary fibrosis and diffusion dysfunction, poorer response to corticosteroid therapy and higher relapse rate. These patients, therefore, should be monitored more closely during therapy or follow-up.

[Reversed halo sign: chest CT findings in 5 patients and cause analysis].

Objective: To describe diseases that may present with the reversed halo sign (RHS) on high-resolution CT, and therefore to improve the recognition of this thoracic radiological feature. Methods: We retrospectively reviewed the HRCT scans and medical records of 5 patients who presented with RHS on chest CT from Peking University Third Hospital. With "reversed halo sign, fairy ring, atoll sign" as the Chinese and English keywords, 420 cases from the literatures were also reviewed through PubMed, Wanfang and CNKI databases until August 2015. Results: The 5 patients were all males, aging 19-55 years. The diagnosis of the diseases included cryptogenic organizing pneumonia (patient 1), pulmonary tuberculosis (patient 2), pulmonary infarction (patient 3), pulmonary edema (patient 4) and mycoplasma pneumonia (patient 5). Literature review showed that RHS was observed in 206 cases of infectious pulmonary diseases and 219 cases of noninfectious pulmonary diseases. Invasive fungal infection (including 59 cases of mucormycosis and 27 aspergillosis) and pulmonary tuberculosis (79 cases) predominated in infectious pulmonary diseases. However, in non-infectious pulmonary diseases, RHS was most frequently observed in organizing pneumonia (66%), sarcoidosis, lung cancer, pulmonary infarction, pulmonary edema and other interstitial lung diseases. There were some differences in the morphologic findings of RHS among invasive fungal infection, pulmonary tuberculosis and organizing pneumonia. In addition, our patient with mycoplasma pneumonia was the first case reported to present with RHS on HRCT. Conclusions: Although a wide spectrum of pulmonary diseases may present with RHS on chest CT, this sign is still a characteristic thoracic radiological feature, which is more commonly found in organizing pneumonia, pulmonary tuberculosis and invasive fungal infection, and is helpful in differential diagnosis.

[Analysis of correlative factors of serum leptin levels in asthmatic patients].

Objective: To analysis the correlative factors that probably affect serum leptin levels in asthmatic patients. Methods: Seventy-eight patients with asthma and 29 health controls who were admitted into outpatient clinic of Peking University Third Hospital from April 2014 to December 2015 were consecutively enrolled in our study prospectively. Serum leptin level was measured by enzyme-linked immunosorbent assay (ELISA). The sex, body mass index (BMI), onset age of asthma, allergen detection test, induced sputum cell count and classification, lung function test and asthma control level were recorded. Asthmatic patients were further divided into groups according to these factors and serum leptin levels were compared among groups. Results: Serum leptin levels were not different between asthmatic patients and health controls [(15.0±10.4) vs (15.2±11.7) µg/L, P=0.939]. Female asthmatic patients had significantly higher serum leptin levels than male [(18.2±10.7) vs (7.9±4.8) µg/L, P<0.001]. Asthmatic patients with obesity had significantly higher serum leptin levels than asthmatic patients with overweight, with normal BMI, with underweight and health controls [(29.7±10.8) vs (17.1±11.1), (11.8±7.7), (9.1±0.96), (15.2±11.7) µg/L, all P<0.01]. Serum leptin level was positively related to percentage of induced sputum eosinophil in female asthmatic patients (r=0.331, P=0.032). Onset age of asthma, positive allergen detection, airflow limitation or asthma control level did not affect serum leptin level. Conclusion: Sex and BMI are important factors affecting serum leptin levels in patients with asthma.

Analysis of FOS, BTG2, and NR4A in the function of renal medullary hypertension.

The aim of this study was to identify differentially expressed genes (DEGs) in renal medullary hypertension and reveal their pathogenic mechanisms. We downloaded the gene expression profile of GSE28360 from the Gene Expression Omnibus database. The profile included 14 samples (5 normal and 9 hypertension). The DEGs in normal and disease samples were distinguished with a false-discovery rate threshold of <0.05 and a fold-change value of >2 or <-2. We put the selected genes into the online program String 8.3 to obtain the protein-protein interaction network and selected the hub proteins. These hub proteins were then placed in the PANTHER database to determine hub protein-related pathways and explain their functions. Finally, we cleared up the single-nucleotide polymorphisms (SNPs) of the hub genes via combing with the National Center for Biotechnology SNP database. A total of 13 genes were identified as DEGs between normal and disease samples. Five selected hub proteins, B-cell translocation gene 2 (BTG2), FBJ murine osteosarcoma viral oncogene homolog (FOS), nuclear receptor subfamily 4, group A, member 1 (NR4A1), NR4A member 2 (NR4A2), and NR4A member 3 (NR4A3), were mainly related to angiogenesis and B-cell activation. After SNP analysis, 103, 103, 595, 150, and 493 SNPs were found to correspond to BTG2, FOS, NR4A1, NR4A2, and NR4A3, respectively. Our results suggest that pathways of angiogenesis and B-cell activation may involve in the progression of renal medulla hypertension.

Early clinical characteristics and pregnancy outcomes of patients with influenza A (H1N1) infection requiring mechanical ventilation during pregnancy.

The early clinical characteristics and pregnancy outcomes of H1N1-infected pregnant women with or without mechanical ventilation were compared. In H1N1-infected pregnant women with mechanical ventilation, the gestational age was greater, the early oxygenation index was lower and early-stage pneumonic lesions were wider than patients without mechanical ventilation. Moreover, compared with the non-mechanical ventilation group, the incidence of the adverse pregnancy outcomes was higher in the mechanical ventilation group.

Expression of chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase in Escherichia coli.

Chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase was expressed in E. coli by using a pET3a T7 RNA polymerase-based expression system and was purified to homogeneity. The kinase and bisphosphatase of the expressed bifunctional enzyme had kinetic properties identical to those of the native chicken liver enzyme. However, the kinase activity of the chicken liver enzyme was 7-fold higher, while the bisphosphatase activity was 50 percent lower than those of the rat liver enzyme. Cys-256 of the rat liver bisphosphatase domain is not conserved in the chicken liver enzyme. A site-directed mutation was engineered at Cys-256 of the rat liver enzyme and the results indicate that the variation of this residue is not responsible for the difference in fructose-2,6-bisphosphatase activity between the rat and chicken liver enzymes. It is postulated that the difference in the kinase/bisphosphatase activity ratios of these two enzymes results from differences in their NH2-terminal regions.

[Comparative analysis of PD25-V50 and PD20-FEV1 as a judgement of bronchial provocation test].

PD25-V50 as a judgement of bronchial provocation test was compared with PD20-FEV1. Both PD25-V50 and PD20-FEV1 showed linear correlation, but PD25-V50 was more sensitive than PD20-FEV1 for the diagnosis of bronchial asthma, and had higher specificity and sensitivity, and lower false-negative and false-positiverate. Moreover PD25-V50 provided the advantages of shorter period of histamine provocation and lower dose of inhaled histamine, so that avoided the side effects of higher dose of histamine.

[Pulmonary changes in progressive systemic sclerosis].

The pulmonary changes of progressive systemic sclerosis in 8 cases were reported. The major clinical complaints were unproductive cough and exertional dyspnea. Pulmonary function tests showed restrictive ventilatory defects and impaired diffusing capacity in most of the cases examined. On chest X-rays, diffuse mottling and linear densities were seen in lungs, predominately in the basal regions. On pathological examinations, pulmonary interstitial fibrosis occurred in early stage of the disease. The results showed that pulmonary involvement may be an early event in progressive systemic sclerosis.

Lipogenesis stimulatory and inhibitory activities of the insulin mediators.

Incubating plasma membranes prepared from pig liver with varying concentrations of insulin (50-1000 microU/ml) resulted in the release of at least two insulin chemical mediators. One of them was fraction 1 of insulin mediator (M. W. 3700-4000 daltons) which had a significant lipogenesis-stimulating activity. The other was fraction 2 of insulin mediator (M. W. about 1000 daltons) which exhibited a lipogenesis-inhibitory activity. The ratio of yield between the two mediators produced from the membranes was not only dependent on the concentration but also on the potency of insulin and its analogs added. The result showed that there was more production of fraction 2 than fraction 1 with the inducer at low concentration (100 microU/ml), while the production of fraction 1 from the plasma membranes incubated with high concentration of insulin (300 microU/ml) was higher than fraction 2. On the other hand, insulin and its analogs which have different biological activities and receptor binding activities have been used to induce the insulin mediators. The results obtained were similar to those mentioned above. This suggested that the generation of the mediators was dependent on the biological potences but not the binding activities.

Adenylate cyclase-modulating mediators of insulin.

Plasma membranes prepared from pig liver incubated with insulin (50-300 microU/ml) resulted in the release of at least two insulin chemical mediators. They appeared to modulate the activity of adenylate cyclase in liver plasma membranes of pig. One of them was fraction 1 of insulin mediator (M. W. about 3700-4000 dalton) which markedly stimulated the activity of the enzyme, the other was fraction 2 of insulin mediator (M. W. about 1000 dalton) which inhibited the enzyme activity. The results showed that the inhibitor of fraction 2 generated was significantly higher than that of fraction 1 when the membranes were incubated with insulin of low concentration (50-100 microU/ml). On the other hand, the generation of stimulator of fraction 1 from plasma membranes incubated with insulin of high concentration (200 microU/ml) was higher than that of fraction 2. So the ratio of yield between two mediators produced from the membranes was dependent on the concentration of insulin added. The results also showed that the effect of fraction 1 of insulin mediator on adenylate cyclase activity in liver cell plasma membranes was biphasic while fraction 2 of insulin mediator showed an inhibitory effect only even though it was at very high concentration. The results that both mediators combined with Gpp(NH)p and forskolin to affect the enzyme activity show that the action of insulin mediators likely resides in the GTP regulatory component of adenylate cyclase.

The role of insulin mediators in regulation of cAMP and lipogenesis as well as in diabetes.

Plasma membranes prepared from pig, mouse and rat liver incubated with insulin resulted in the release of at least two insulin chemical mediators. These mediators, identified as fractions 1 and 3, were found to inhibit cAMP level in response to lipolytic hormone and forskolin and to enhance lipogenesis in adipocytes of rat. Fractions 1 and 3 have been estimated to have molecular weights of 3700-4000 and 1000-1500 dalton, respectively. This initial report will focus on fraction 1. Interestingly, liver membranes from diabetic animals were found not to release mediators in the presence of insulin. However, following in vivo treatment of diabetic animals with insulin, the liver membranes appeared to restore its ability in generating chemical mediators in response to insulin.