[Clinical outcome of posterior lumbar interbody fusion combined with Ponte osteotomy for reconstruction of coronal sagittal plane balance in degenerative scoliosis].

Objective: To evaluate the clinical efficacy of posterior lumbar interbody fusion combined with Ponte osteotomy in the treatment of patients with degenerative scoliosis. Methods: The medical records and imaging data of degenerative scoliosis in department of orthopedics, Peking Union Medical College Hospital from 2013 to 2022 were retrospectively collected, and the shortest follow-up time was 1 year. A total of 38 patients were included, including 13 males and 25 females, aged 50-87(65.6±10.9) years old.The follow-up was12-119(43±20) months. Standing position full spine anteroposterior lateral X-ray examinations were performed on all patients preoperatively, postoperatively, and at latest follow-up. The length of hospital stay, complications, operation time, blood loss, instrumented segment, fusion segmen were recorded. The clinical scores and coronasagittal imaging indicators at three time points were compared. Results: The operation time was (274.5±70.5)min, and intraoperative blood loss was (619.2±93.5)ml. The coronal vertical axis was improved from (2.9±1.8)cm preoperatively to (1.2±1.0)cm postoperatively. The preoperative coronal Cobb angle was 16.6°±9.9° and the immediate postoperative correction was 6.4°±4.0°(t=-6.83, P<0.001). The difference was statistically significant (t=-6.12, P<0.001). The coronal Cobb Angle at the last follow-up was 5.7°±3.7°, and there was no significant orthopaedic loss at the last follow-up (t=-6.12, P<0.001).The sagittal vertical axis decreased from (5.6±3.9)cm preoperatively to (3.2±2.5) cm immediately after operation (t=-6.83,P<0.001), and was well maintained at the last follow-up[(2.7±1.8) cm,t=-7.77,P<0.001]. Lumbar lordosis increased from 21.8°±10.2° preoperatively to 35.8°±8.3° postoperatively(t=12.01, P<0.001)and 40.1°±8.6° at last follow-up(t=-10.21, P<0.001). Oswestry disability score (ODI score), visual analogue score (VAS) low back pain score and VAS leg pain score were also lower after surgery than before surgery (all P<0.05). Conclusion: Posterior lumbar interbody fusion combined with Ponte osteotomy can significantly improve the coronal and sagittal plane deformity and postoperative functional score in adult patients with degenerative scoliosis.

[Comparison of the therapeutic effects of optic nerve sheath fenestration and medication on papilledema due to cerebral venous thrombosis].

Objective: To compare the therapeutic effects of optic nerve sheath fenestration (ONSF) and medication on papilledema induced by cerebral venous thrombosis (CVT). Methods: Patients with papilledema induced by CVT in Beijing Tiantan Hospital and Xuanwu Hospital from January 2017 to July 2022 were retrospectively enrolled and were divided into two groups according to the treatment strategies they underwent, with 76 cases (107 eyes) in ONSF group and 35 cases (69 eyes) in medication group. The degree of papilledema was evaluated by the modified Frisén's grading (grade 0-1 was defined as mild, grade 2-3 was moderate, and grade 4-5 was severe edema). The mean defect (MD) of visual field, the degree of papilledema, and the mean retinal nerve fiber layer (RNFL) thickness in different subgroups were compared between baseline versus 1 month after ONSF or medication. Results: There were 76 cases in ONSF group (26 males and 50 females), and aged (35.3±11.4) years. Meanwhile, there were 35 cases in medication group (22 males and 13 females), and aged (35.2±11.0) years. Compared with baseline, MD were improved in both moderate [(-8.4±6.6) vs (-11.8±8.6) db, P=0.021] and severe [(-8.1±5.3) vs (-11.4±6.9) db, P<0.001] papilledema subgroups after ONSF, while there was an improvement in mild papilledema subgroup [(-1.5±5.3) vs (-3.4±5.1) db, P<0.001] after medication. The papilledema (Frisén's scores) in both ONSF group (P<0.001) and medication group (P=0.010) was improved. Compared with baseline, the mean RNFL decreased in mild [(78.5±13.5) vs (91.0±17.4) µm, P=0.002], moderate [(126.6±67.6) vs (154.8±77.9) µm, P=0.011] and severe [(179.0±70.9) vs (230.6±89.7) µm, P=0.001] papilledema subgroups after ONSF, while the mean RNFL decreased [(142.0±29.3) vs (158.8±22.7) µm, P=0.020] in moderate papilledema subgroup after medication. Conclusions: ONSF might attenuate CVT-mediated papilledema, and improve the visual function in patients with moderate and severe papilledema. Likewise, patients with mild papilledema could also get benefit from medication.

[The role of Keap1/Nrf2/HO-1 signal pathway in liver injury induced by rare earth neodymium oxide in mice].

Objective: To investigate the role of Keap1/Nrf2/HO-1 signaling pathway in liver injury induced by neodymium oxide (Nd(2)O(3)) in mice. Methods: In March 2021, forty-eight SPF grade healthy male C57BL/6J mice were randomly divided into control group (0.9% NaCl), low dose group (62.5 mg/ml Nd(2)O(3)), medium dose group (125.0 mg/ml Nd(2)O(3)), and high dose group (250.0 mg/ml Nd(2)O(3)), each group consisted of 12 animals. The infected groups were treated with Nd(2)O(3) suspension by non-exposed tracheal drip and were killed 35 days after dust exposure. The liver weight of each group was weighed and the organ coefficient was calculated. The content of Nd(3+) in liver tissue was detected by inductively coupled plasma mass spectrometry (ICP-MS). HE staining and immunofluorescence was used to observe the changes of inflammation and nuclear entry. The mRNA expression levels of Keap1, Nrf2 and HO-1 in mice liver tissue were detected by qRT-PCR. Western blotting was used to detect the protein expression levels of Keap1 and HO-1. The contents of catalase (CAT), glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD) were detected by colorimetric method. The contents of interleukin 1ß (IL-1ß), interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) were determined by ELISA. The data was expressed in Mean±SD. Two-independent sample t-test was used for inter-group comparison, and one-way analysis of variance was used for multi-group comparison. Results: Compared with the control group, the liver organ coefficient of mice in medium and high dose groups were increased, and the Nd(3+) accumulation in liver of mice in all dose groups were significantly increased (P<0.05). Pathology showed that the structure of liver lobules in the high dose group was slightly disordered, the liver cells showed balloon-like lesions, the arrangement of liver cell cords was disordered, and the inflammatory exudation was obvious. Compared with the control group, the levels of IL-1ß and IL-6 in liver tissue of mice in all dose groups were increased, and the levels of TNF-α in liver tissue of mice in high dose group were increased (P<0.05). Compared with the control group, the mRNA and protein expression levels of Keap1 in high dose group were significantly decreased, while the mRNA expression level of Nrf2, the mRNA and protein expression levels of HO-1 were significantly increased (P<0.05), and Nrf2 was successfully activated into the nucleus. Compared with the control group, the activities of CAT, GSH-Px and T-SOD in high dose group were significantly decreased (P<0.05) . Conclusion: A large amount of Nd(2)O(3) accumulates in the liver of male mice, which may lead to oxidative stress and inflammatory response through activation of Keap1/Nrf2/HO-1 signal pathway. It is suggested that Keap1/Nrf2/HO-1 signal pathway may be one of the mechanisms of Nd(2)O(3) expose-induced liver injury in mice.

[Complications of chronic cough].

Chronic cough is a common complaint, which may cause various complications involving many organ systems, including respiratory system, circulatory system, digestive system, urinary system, reproductive system, skeletal movement system, nervous system, etc. Cough and its complications are associated with an adverse impact on the work and quality of life in the huge population with chronic cough, and lead to an increased healthcare resource utilization. In this paper, we review the common complications of chronic cough by organ system classification.

[Updated key points of Chinese Consensus for the Diagnosis and Treatment of Acromegaly (2021 edition)].

Led by the China Pituitary Adenoma Specialist Council, the Chinese Consensus for the Diagnosis and Treatment of Acromegaly (2021 Edition) is developed combined with the research progress of pituitary growth hormone (GH)-secreting adenoma both at home and abroad, evidence-based evidence of the diagnosis and treatment of acromegaly, and China's national conditions. Based on the guideline for acromegaly (2013 Edition), the new version of consensus emphasizes the importance of multidisciplinary team (MDT) and individual therapy. The criteria for control of acromegaly is discussed. Pathological criteria for the diagnosis of pituitary GH-secreting adenoma is updated. New developments in surgery, drug and radiotherapy are introduced. Meanwhile, the diagnosis and treatment of acromegaly patients concurrent with other particular scenarios, including pregnancy and refractory pituitary GH-secreting adenoma is suggested. This article aims to describe the updated key points of the new version of the consensus, and thus facilitate the clinical implementation of standardized diagnosis and treatment for acromegaly patients.

Dunye Guanxinning Improves Acute Myocardial Ischemia-Reperfusion Injury by Inhibiting Neutrophil Infiltration and Caspase-1 Activity.

Acute myocardial infarction is the most serious manifestation of cardiovascular disease, and it is a life-threatening condition. Dunye Guanxinning (DG) is a protective traditional Chinese patent herbal medicine with high clinical efficacy and suitable for the treatment of myocardial infarction. However, the mechanism through which it is beneficial is unclear. In this study, we hypothesized that DG improves acute myocardial ischemia-reperfusion injury by inhibiting neutrophil infiltration and caspase-1 activity. We found that DG administration decreased infarct size and cardiomyocyte apoptosis and improved left ventricular ejection fraction, fractional shortening, end-systolic volume index, end-systolic diameter, and carotid arterial blood flow output in rats. DG administration also improved hemorheological parameters, myocardial damage biomarkers, and oxidative stress indexes. The findings showed that DG administration inhibited neutrophil infiltration and reduced the serum interleukin-1 beta (IL-1ß) level and myocardial IL-1ß maturation. Moreover, DG administration inhibited caspase-1 activity and activated adenosine monophosphate-activated protein kinase (AMPK) phosphorylation in rat hearts. These results suggested that DG administration inhibits inflammasome activity and IL-1ß release through the AMPK pathway. Our findings support the clinical efficacy of DG and partially reveal its mechanism, which is beneficial for understanding the therapeutic effects of this protective traditional Chinese patent drug.

Metallophthalocyanines as triplet sensitizers for highly efficient photon upconversion based on sensitized triplet-triplet annihilation.

Soluble palladium and platinum phthalocyanines with coumarin moieties were synthesized with Q bands in the red and near-IR regions, in which the molar extinction coefficients were up to 1.01 × 10(5) cm(-1) mol(-1). These metallophthalocyanines were coupled with rubrene and applied in photon upconversion systems based on triplet-triplet annihilation. The highest upconversion efficiency of the palladium phthalocyanine was 5.6%, which is higher than that of the platinum phthalocyanine-rubrene system. The larger molar extinction coefficient resulted in high upconversion capability (>10(5) cm(-1) mol(-1)) and low saturation incident power (<20 mW cm(-2)).

Changes in skinfold thickness and body composition among children and adolescents in Shandong, China from 1995 to 2010.

BACKGROUND: There is strong evidence of a upward secular trend in skinfold thickness (SFT) and the prevalence of obesity has increased substantially over recent decades in developed countries. However, no studies on this trend have been reported in Shandong Province, China. The present study aimed to assess the decennial change in SFT and body composition among children and adolescents in Shandong Province during the past 15 years (1995-2010). METHODS: Data were obtained from two national surveys on student's constitution and health carried out by the government in 1995 and 2010 in Shandong Province, China. A total of 14 780 (7198 in 1995 and 7582 in 2010) students aged 7-18 years participated in the present study. Weight and SFT of all subjects were measured. Percentage body fat (%FM) was estimated by SFT, and fat mass (FM) and fat-free mass (FFM) were calculated from: FM (kg) = %FM × weight (kg)/100; FFM (kg) = weight (kg)-FM(kg). The range of differences of weight, SFT, FM and FFM over the different age groups between the 1995 and 2010 samples were calculated. RESULTS: In the past 15 years, mean values of SFT have increased. The mean (range) increments of SFT were 6.28 (2.91-11.22) mm for boys and 3.29 (2.22-4.29) mm for girls, demonstrating a mean increase of 32% for boys and 14% for girls. The mean (range) increments of weight, FM and FFM were 7.26 (4.41-10.82) kg, 3.70 (1.47-6.58) kg and 3.56 (1.24-5.27) kg, at rates of 18%, 47% and 10% for boys, respectively, and 4.14 (2.78-5.64) kg, 1.68 (1.02-2.27) kg and 2.46 (1.52-3.49) kg, at rates of 11%, 20% and 8% for girls, respectively. CONCLUSIONS: The mean values of SFT, FM and FFM have increased over time. Rates of increase were greater for FM than FFM.

Weighted gene co-expression network analysis of key targets and interventional mechanism of Milkvetch root in diabetic nephropathy.

OBJECTIVE: This work aimed to explore the key targets and intervention mechanisms of Huangqi (Astragalus membranaceus) in diabetic nephropathy using weighted gene co-expression network analysis (WGCNA). The findings will provide references for identifying critical therapeutic targets for diabetic nephropathy. MATERIALS AND METHODS: The GSE1009 dataset was selected from the Gene Expression Omnibus (GEO) database of the National Center for Biotechnology Information (NCBI) for analysis. WGCNA network was constructed to identify differentially expressed genes (DEGs). Gene ontology (GO) and pathway enrichment analysis were performed on the DEGs. RESULTS: There were 752 downregulated DEGs and 1,547 upregulated DEGs in the diabetic nephropathy samples. Genes such as PLCE1, CLIC5, PTPRO, HSPA12A, AIF1, GMDS, and SEMA5A were significantly suppressed in the diabetic nephropathy samples, while genes such as CEP152, LUNAR1, and SLC9A1 were significantly upregulated. The optimal soft threshold for the WGCNA network was determined as 12. Hierarchical clustering analysis was conducted to detect co-expression modules with corresponding color assignments, and a total of 9 modules were identified. Clinical characteristics showed a high correlation with the gray, blue, green, and brown modules of the WGCNA. GO analysis and KEGG pathway enrichment analysis revealed that the blue module DEGs were mainly enriched in immune response, inflammatory response, signal transduction, plasma membrane, extracellular region, cell surface, extracellular matrix, and proteinaceous extracellular matrix. The green module DEGs were mainly enriched in mitochondrial elongation, mitochondrial mutation termination, translation, mitochondrial inner membrane, mitochondrion, ATP biosynthetic process, mitochondrial large ribosomal subunit, mitochondrial intermembrane space, nucleolus, and ribosome. Visualization analysis of the bioactive components of Huangqi showed compounds such as quercetin, resveratrol, 7-O-methylisomucronulatol, and isoquercetin, which had more targets. CONCLUSIONS: Differentially expressed genes in diabetic nephropathy were mainly enriched in immune response and inflammatory response. Various components of Huangqi have positive application value in the treatment of diabetic nephropathy and can be considered for clinical promotion.

Comparative molecular analysis of meticillin-resistant Staphylococcus aureus isolates from children with atopic dermatitis and healthy subjects in Taiwan.

BACKGROUND: Children with atopic dermatitis (AD) are more frequently colonized by Staphylococcus aureus than healthy children. OBJECTIVES: To assess whether any relationship exists between nasal meticillin-resistant S. aureus (MRSA) colonization and subsequent skin and soft-tissue infections (SSTI). PATIENTS AND METHODS: From 2005 through 2006, comparative molecular analyses of 23 MRSA-colonizing isolates from 133 children with AD, 44 MRSA-colonizing isolates from 490 healthy controls, and 12 MRSA-infecting isolates from 20 children with AD and concurrent SSTI were conducted. RESULTS: Nasal MRSA colonization in children with AD was significantly higher compared with normal individuals (17.3% vs. 9.0%; P = 0.01). The molecular characteristics differed significantly between the MRSA isolates from children with AD and the MRSA-colonizing isolates from healthy controls. The clone characterized as sequence type (ST)59 (338)/pulsotype B/staphylococcal cassette chromosome mec (SCCmec) V(T)/Panton-Valentine leucocidin (PVL)-positive/staphylococcal enterotoxin B (SEB)-positive accounted for half of the MRSA isolates from children with AD, and another clone, characterized as ST59/pulsotype A/SCCmec IV/PVL-negative/SEB-positive accounted for 61% of the MRSA-colonizing isolates from healthy controls. CONCLUSIONS: We found MRSA colonizing the anterior nares of a large number of Taiwanese children, especially among those with AD. Analysis of our data provides evidence that links MRSA-colonizing isolates to MRSA-infecting isolates from concurrent SSTI in children with AD.

SP1-induced lncRNA LINC00689 overexpression contributes to osteosarcoma progression via the miR-655/SOX18 axis.

OBJECTIVE: Many findings have demonstrated long noncoding RNAs (lncRNAs) as crucial regulatory molecules in the progression of osteosarcoma. The aim of this study was to explore the roles and mechanisms of LncRNA LINC00689 (LINC00689) in osteosarcoma. PATIENTS AND METHODS: Differential levels of LINC00689 and miR-655 in osteosarcoma samples and cell lines were analyzed by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The associations between LINC00689 expression and prognostic significance of osteosarcoma patients were analyzed using a series of statistical assays. Loss-of-function and gain-of-function assays were performed to investigate the role of LINC00689 in proliferation and metastasis in vitro. Bioinformatic assays, Luciferase report assays, and rescue assays were applied to illustrate the ceRNA mechanism network of LINC00689/miR-655/SOX18. RESULTS: We found that LINC00689 expression was distinctly upregulated in osteosarcoma specimens and cell lines. MiR-655 displayed a trend of remarkably decreased expression in osteosarcoma tissues. In addition, we showed that LINC00689 could specifically interact with the promoter of SP1 and activate LINC00689 transcription. Further clinical studies indicated that higher levels of LINC00689 were associated with advanced clinical stage, positively distant metastasis, and unfavorable clinical outcome. Functional studies revealed that the knockdown of LINC00689 suppressed the proliferation, migration, and invasion of osteosarcoma cells, and promoted apoptosis. Final mechanistic investigations confirmed that upregulation of LINC00689 competitively bound to miR-655 that prevented SOX18 from miRNA-mediated degradation, thus facilitating osteosarcoma progression. CONCLUSIONS: All our findings suggested that SP1-induced upregulation of LINC00689 promoted osteosarcoma progression by regulating miR-655/ SOX18 axis, which provided a novel insight for osteosarcoma tumorigenesis.

Circular RNA circ_0103552 promotes the invasion and migration of thyroid carcinoma cells by sponging miR-127.

OBJECTIVE: The aim of this study was to examine the regulatory role of circ-0103552 in the procession of thyroid carcinoma (TC) and the related underlying mechanisms. PATIENTS AND METHODS: The tissues were obtained from 56 patients diagnosed with TC in our hospital. Nthy-ori3-1 cell line and TC cell lines (TPC-1, SW579, 8505C) were purchased from American Type Culture Collection (ATCC). Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was conducted to analyze the expression of circ-0103552 in TC tissues and cell lines. Inhibition of circ-0103552 was achieved by circ-0103552 siRNA. Dual-Luciferase report assay was performed to confirm the potential target miRNA of circ-0103552. The transwell assay and wound-healing assay were designed to examine the invasion and migration ability of TC cells, respectively. RESULTS: Circ-0103552 was detected to be upregulated in TC tissues, as well as in TC cell lines, including TPC-1, SW579, and 8505C. The knockdown of circ-0103552 significantly reduced the invasion and migration ability in TC cells. It was predicted using the circular RNA database that microRNA-127 (miR-127) was a target miRNA of circ-0103552, which was confirmed by the Dual-Luciferase assay. Further studies revealed that circ-0103552 was involved in the invasion and migration of TC by sponging miR-127. CONCLUSIONS: The present study demonstrated that circ-0103552 acts as a regulator in the invasion and migration of TC by sponging miR-127.

[Diagnostic value of ultrasonic elastic strain ratio and elasticity score for thyroid micronodules of TI-RADS 4].

Objective: To investigate diagnostic value of ultrasonic elastic strain ratio and elasticity score for thyroid micronodules of TI-RADS 4. Method: In total, 211 consecutive patients with 225 thyroid micronodules were enroled in the study, all the nodules were evaluated by TI-RADS criteria before and all of them were examined by elastic imaging. We set the histology as the reference standard. The elastic strain ratio and elasticity score values, as well as their diagnostic threshold and efficiency, were compared and analyzed by the receiver operating characteristic(ROC) curve. Result: Statistically significant differences(P<0.05) in both elastic strain ratio and elasticity score values were detected among the thyroid microcarcinoma and benign groups. The area under the ROC curve of elastic strain ratio was significantly greater than that of elasticity score(0.935 and 0.825, respectively; P<0.05). Using elastic strain ratio ≥3.45 and elasticity score ≥3.00 as diagnostic threshold values, the diagnostic sensitivity, specificity, and accuracy of elastic strain ratio for differentiating benign and malignant nodules were 86.51%, 90.32%, and 87.56%, respectively, whereas those of elasticity score were 80.98%, 79.03% and 80.44%, respectively. Conclusion: Ultrasonic elastic strain ratio and elasticity score have very high diagnostic value for the thyroid micronodules of TI-RADS 4, and strain ratio has more advantages.

Trends in atmospheric particles and their light extinction performance between 1980 and 2015 in Beijing, China.

This study explored the interdecadal variations and their horizontal and vertical light extinction performances of atmospheric particulate matter with aerodynamic diameters ≤2.5 µm (PM2.5), particulate matter with aerodynamic diameters ≤ 10 µm (PM10), and total suspended particulates (TSPs) in Beijing from 1980 to 2015, using data available from historical publications. Prominent declines of PM2.5, PM10, and TSPs were detected with long-term linear trends of -6.7, -4.3, and -1.9 µg m-3 yr-1, respectively. Generally, on the annual scale during the studied period, it was found that PM2.5 displayed negative correlation (R2 = 0.38, p < 0.01) with visibility and positive correlation (R2 = 0.41, p < 0.01) with aerosol optical depth (AOD). Comparably, PM10 exhibited robust negative correlation (R2 = 0.61, p < 0.01) with visibility and positive correlation (R2 = 0.82, p < 0.01) with AOD. The complicated interdecadal variations and light extinction performances of PM2.5 were found, suggesting the changes on particle composition and vertical distribution of PM2.5 in the atmosphere.

Beneficial effect of recombinant human growth hormone on the intestinal mucosa barrier of septic rats.

The objective of the present study was to investigate the effects of recombinant human growth hormone (rhGH) on the intestinal mucosa barrier of septic rats and explore its possible mechanism. Female Sprague-Dawley rats were randomized into three groups: control, Escherichia coli-induced sepsis (S) and treatment (T) groups. Groups S and T were subdivided into subgroups 1d and 3d, respectively. Expression of liver insulin-like growth factor-1 (IGF-1) mRNA, Bcl-2 and Bax protein levels and the intestinal Bax/Bcl-2 ratio, and plasma GH and IGF-1 levels were determined. Histological examination of the intestine was performed and bacterial translocation was determined. rhGH significantly attenuated intestinal mucosal injuries and bacterial translocation in septic rats, markedly decreased Bax protein levels, inhibited the decrease of Bcl-2 protein expression and maintained the Bax/Bcl-2 ratio in the intestine. rhGH given after sepsis significantly improved levels of plasma GH (T1d: 1.28 +/- 0.24; T3d: 2.14 +/- 0.48 microg/L vs S1d: 0.74 +/- 0.12; S3d: 0.60 +/- 0.18 microg/L; P < 0.05) and IGF-1 (T1d: 168.94 +/- 65.67; T3d: 201.56 +/- 64.98 microg/L vs S1d: 116.72 +/- 13.96; S3d: 107.50 +/- 23.53 microg/L; P < 0.05) and expression of liver IGF-1 mRNA (T1d: 0.98 +/- 0.20; T3d: 1.76 +/- 0.17 vs S1d: 0.38 +/- 0.09; S3d: 0.46 +/- 0.10; P < 0.05). These findings indicate that treatment with rhGH had beneficial effects on the maintenance of the integrity of the intestinal mucosa barrier in septic rats.

Adsorption of ionized and neutral pentachlorophenol to phosphatidylcholine membranes.

We have studied adsorption of pentachlorophenol (PCP) to phosphatidylcholine (PC) membranes by measuring the electrophoretic mobility of multilayered lipid vesicles in PCP solutions. PC vesicles become negatively charged due to the adsorption of ionized PCP, and we have found that their zeta potential depends upon the ionic strength and pH of the aqueous suspension. We have shown that the experimental results can be adequately accounted for in terms of a two-component Langmuir-Stern-Grahame adsorption model assuming that the 'PCP adsorption sites' are occupied either by the neutral (HA) or the ionized (A-) species. The characteristics of adsorption isotherms of the PCP - PC membrane are as follows: the association constants are KA = 55,000 dm3/mol, KHA = 279,000 dm3/mol; 4.3 PC molecules make up each PCP adsorption site at saturation; the linear partition coefficients are beta HA = (15.5 +/- 0.7) x 10(-5) m and beta A = (3.0 +/- 0.3) x 10(-5) m. The properties of PCP adsorption isotherms for PC membranes predict an increased pKa value of membrane-bound PCP, which has been observed in related studies.

Regulation of HMG-CoA reductase, apoprotein-B and LDL receptor gene expression by the hypocholesterolemic drugs simvastatin and ciprofibrate in Hep G2, human and rat hepatocytes.

The comparative effects of simvastatin (a competitive inhibitor of HMG-CoA reductase) and ciprofibrate (another inhibitor of cholesterogenesis) on the incorporation of [14C]acetate and [3H]mevalonate into cholesterol HMG-CoA reductase activity, apo-B synthesis, LDL receptor, and their corresponding mRNAs, have been studied in the human hepatoma cell line Hep G2 and in human and rat hepatocytes in primary culture. Incubation of Hep G2 with simvastatin (0.01-1.5 microM) or ciprofibrate (25-100 microM) produced not only a marked inhibition of cholesterogenesis from [14C]acetate but also from [3H]mevalonate, an intermediate downstream of the HMG-CoA reductase reaction. However, in human and rat hepatocytes, cultured in similar conditions, simvastatin inhibited only the cholesterol synthesis from [14C]acetate, as expected. HMG-CoA reductase activity was greatly induced in Hep G2 and rat hepatocytes after incubation with simvastatin (up to 400% of controls), but not with ciprofibrate. Increased enzyme activity was accompanied by a higher cell content of reductase mRNA. Apo-B concentration in the medium of Hep G2 cells was 31% lower after 31 h incubation with simvastatin than in controls. However, neither simvastatin nor ciprofibrate modified the synthesis rate of apo-B or its mRNA level. Both LDL-receptor and its mRNA levels were raised by simvastatin at concentrations inhibiting cholesterol synthesis. Our data show that, in this human hepatoma cell line, HMG-CoA reductase competitive inhibition by simvastatin triggers a coordinate regulation of the expression of genes coding for reductase and LDL receptor but not for apo-B. Ciprofibrate, though efficient in inhibiting cholesterogenesis, did not induce the same regulatory reactions. The reason for this discrepancy is unknown.

Lipid and lipoprotein metabolism in Hep G2 cells.

Lipid composition, lipid synthesis and lipoprotein secretion by the Hep G2 cell line have been studied with substrate and insulin supplied under different conditions. The lipid composition of Hep G2 cells was close to that of normal human liver, except for a higher content in sphingomyelin (P less than 0.005) and a lower phosphatidylcholine/sphingomyelin ratio. Most of the [14C]triacylglycerols secreted into the medium were recovered by ultracentrifugation at densities of 1.006 to 1.020 g/ml. The main apolipoproteins secreted were apo B-100 and apo A-I. Hep G2 mRNA synthesized in vitro the pro-apolipoproteins A-I and E. Triacylglycerol secretion was 7.38 +/- 1.04 micrograms/mg cell protein per 20 h with 5.5 mM glucose in the medium and increased linearly with glucose concentration. Oleic acid (1 mM) increased the incorporation of [3H]glycerol into the medium and cell triacylglycerols by 251 and 899%, with a concomitant increment in cell triacylglycerols and cholesterol ester. Insulin (1 mU or 7 pmol/ml) inhibited triacylglycerol secretion and [35S]methionine incorporation into secreted protein by 47 and 28%, respectively, with a corresponding increase in the cells. Preincubation of cells with 2.5-10 mM mevalonolactone decreased the incorporation of [14C]acetate into cholesterol 6.2-fold, indicating an inhibitory effect on HMG-CoA reductase. It is concluded that in spite of some differences between Hep G2 and normal human hepatocytes, this line offers an alternative and reliable model for studies on liver lipid metabolism.

Lipid and lipoprotein synthesis in isolated and cultured hepatocytes from lean and obese Zucker rats.

Hepatocytes were isolated by EDTA perfusion of livers from lean (Fa/-) and obese (fa/fa) Zucker rats. Triacylglycerol (TG) and sn-glycerol 3-phosphate were increased in fa/fa hepatocytes, but free fatty acids, cholesterol and phospholipid concentrations were similar in both groups. In spite of an identical fatty acid uptake rate, glycerolipid synthesis was higher in obese compared to lean rat hepatocytes, and this difference remained for at least 2-3 days of culture. Triacylglycerol mass secretion was 2-fold higher in obese than in lean rat hepatocytes. This was confirmed by the higher incorporation of labeled glycerol and oleic acid into the medium TG fraction floating at density 1.006 g/ml. Density gradient ultracentrifugation of [14C]oleate-labeled lipoproteins showed that fa/fa hepatocytes secreted more TG-rich lipoproteins, and that 87% of the label was in the VLDL fraction compared with 67% in the medium of Fa/- hepatocytes. Decreased utilisation of leucine for protein synthesis in obese rat compared to lean rat hepatocytes was associated with enhanced leucine oxidation to CO2. [35S]Methionine incorporation showed an identical cell protein synthesis rate. Autoradiography after PAGE separation of secreted apolipoproteins (apoBh, Bl, apoA-VI, apoE, apoA-I, apoC) showed an identical pattern in both cell types.