[Risk factors for mortality in pediatric acute respiratory distress syndrome requiring extracorporeal membrane oxygenation support]

Objective: To explore the risk factors for mortality in pediatric acute respiratory distress syndrome (PARDS) requiring extracorporeal membrane oxygenation (ECMO) support. Methods: Clinical data of 109 patients with severe PARDS supported by ECMO, who were hospitalized in 6 ECMO centers in China from September 2012 to February 2020, were retrospectively analyzed. They were divided into survival group and death group according to the prognosis. Chi-square test and rank sum test were used to compare the variables between the two groups, including the demographic data, laboratory examination results, clinical data before and after ECMO, and other supportive treatment. Univariate and multivariate Logistic regression models were used to analyze the prognostic risk factors. Results: In these 109 cases, 54 died and 55 survived. Compared with the survival group, the death group had higher incidences of acute kidney injury (AKI) (48.1% (26/54) vs. 21.8% (12/55), χ²=8.318, P=0.004) and coagulation dysfunction (22.2% (12/54) vs. 7.3% (4/55), χ²=4.862, P=0.027), and higher rate of renal replacement therapy (48.1% (26/54) vs. 21.8% (12/55), χ²=9.694, P=0.008) during ECMO support. Logistic regression analysis showed that continuous renal replacement therapy (CRRT) and AKI were independent risk factors for death in patients with severe PARDS requiring ECMO support (HR=3.88,95%CI 1.04-14.52, HR=4.84,95%CI 1.21-19.46, both P<0.05). Conclusion: AKI and CRRT are independent risk factors for predicting mortality in patients with severe PARDS requiring ECMO support.

[Interfacility transport with extracorporeal membrane oxygenation in pediatric patients: a multicenter study in China]

Objective: To investigate application and safety of pediatric interfacility-transport with extracorporeal membrane oxygenation (ECMO) in China. Methods: The data of 48 patients transported inter-hospital from February 2016 to May 2018 were collected from the following 4 centers: pediatric intensive care unit (PICU) of Bayi Children's Hospital Affiliated to the 7th Medical Center of PLA General Hospital, Pediatric Hospital of Fudan University, Henan Provincial People's Hospital and Children's Hospital of Zhejiang University School of Medicine. The data of patients' characteristics, ECMO mode and wean rate, and mortality were reviewed, which was further compared with the data of 57 compatible inner-hospital ECMO cases with t test, Rank sum test or chi-square test. Results: All the 48 interfacility-transports were accomplished by ambulance on land, with an average transfer distance of (435±422) km. The incidence of ECMO complications was 13% (6 case), without death. There were no significant differences in lactic acid, PaO(2) or SaO(2) before and after transport (4.0 (2.0, 7.5) vs. 3.0 (1.5, 6.0) mmol/L, Z=-1.579, P>0.05; 112(47, 405) vs. 166(122, 240) mmHg (1 mmHg=0.133 kPa), Z=-0.104, P>0.05; 0.97±0.02 vs. 0.96±0.03, t=1.570, P>0.05). Instead, PaCO(2) and pH were significantly different ((47±8) vs. (42±5) mmHg, t=2.687, P<0.05; 7.3±0.2 vs. 7.5±0.2, t=3.379, P<0.05). The total ECMO weaned rate was 73% (35/48) and the survival rate was 67% (32/48). No significant differences in demographic characteristics, ECMO mode or duration, transport distance or duration, or complications existed between the survival group and the death group (7/25 vs. 2/14, χ(2)=0.615, P>0.05; 4/28 vs. 2/14, χ(2)=0, P>0.05; (405±404) vs. (493±465) km, t=0.525, P>0.05; (5±4) vs. (5±5) h, t=0.388, P>0.05; 166 (128, 239) vs. 187(52, 405) h, Z=-0.104, P>0.05; 3/32 vs. 3/16, χ(2)=0.734, P>0.05). The lowest lactate value in survival group before ECMO transport was significantly lower than that in the death group ((5±5) vs. (8±6) mmol/L, t=2.151, P<0.05). There were neither significant differences in age, ECMO mode or support pattern (9/39 vs. 15/42, χ(2)=0.845, P>0.05; 6/42 vs. 7/50, χ(2)=0.001, P>0.05; 29/19 vs. 38/19, χ(2)=0.441, P>0.05), nor in ECMO weaned rate, survival rate or complications between interfacility-transport group and inner-hospital group (35/48 vs. 37/57, χ(2)=0.775, P>0.05; 32/48 vs. 35/57, χ(2)=0.313, P>0.05; 20/48 vs. 22/57, χ(2)=0.102, P>0.05). Conclusion: With appropriate transport equipment and mature teams who handle problems timely during the transport, critically ill children could be safely transported to the destination with ECMO.

[Study on radiation dose in different field of views of oral and maxillofacial cone-beam CT]

Objective: To analyze the absorptive radiation dose of non-target sensitive organs under the NewTomVGi oral and maxillofacial cone-beam CT scanning in different view fields. Methods: The thermoluminescence dosimeter chip was placed in the non-target sensitive organ of the simulated radiology head model, and 6 scanning fields were measured and analyzed (standard resolution: scanning range was 15 cm×15 cm, 15 cm×12 cm, 12 cm×8 cm, 8 cm×8 cm respectively). High definition resolution: the radiation absorption dose of thermoluminescence with the scanning range of 12 cm×8 cm, 8 cm×8 cm, respectively. Results: Under the same resolution, the absorptive dose increased with the expansion of scanning field, and the amount of absorbent during high resolution scanning was higher than that during the standard resolution with the same scanning field. Conclusions: New TomVGi oral and maxillofacial cone-beam CT has sighificant difference in radiation dose in different view fields. The appropriate view field should be selected according to the patient's clinical needs, so as to reduce unnecessary radiation dose during medical imaging examination.

[Four cases of acute respiratory distress syndrome patients transported with veno-venous extracorporeal membrane oxygenation]

Objective: To retrospectively review 4 cases diagnosed with pediatric acute respiratory distress syndrome (ARDS) who were transported with veno-venous (V-V) extracorporeal membrane oxygenation (ECMO) from April 2016 to March 2017. Methods: Four patients were transported to Bayi Children's Hospital Afflicted to the PLA Army General Hospital, with V-V ECMO. Their vital signs, blood-gas analysis and chest X-ray before and after transportation were compared. The length of ECMO, pediatric intensive care unit (PICU) stay and hospitalization, and the prognosis were analyzed. Results: All the four cases were transported to our hospital successfully from distances between 1 000 km to 1 210 km. The 4 cases were 4 to 6 years old with the body weight of 19 to 35 kg, of whom 3 were boys and 1 was girl. The catheters were inserted in the right jugular vein and femoral vein. The vital signs and blood-gas analysis after transportation did not change significantly compared to baseline. The length of ECMO for the four patients were 48, 754, 157 and 438 hours. They stayed in the PICU for 10, 32, 14 and 19 days, respectively. At last, 2 of them were successfully discharged from hospital without any complications; however, the other 2 died of multiple organ failure. Conclusion: Transporting ARDS patients with a satisfactory cardiac function under VV-ECMO by an experienced ECMO team is safe.

Clinical analysis of cases of neonatal Streptococcus agalactiae sepsis

With the advent of antibiotic resistance, pathogenic bacteria have become a major threat in cases of neonatal sepsis; however, guidelines for treatment have not yet been standardized. In this study, 15 cases of neonatal Streptococcus agalactiae sepsis from our hospital were retrospectively analyzed. Of these, nine cases showed early-onset and six cases showed late-onset sepsis. Pathogens were characterized by genotyping and antibiotic sensitivity tests on blood cultures. Results demonstrated that in cases with early-onset sepsis, clinical manifestations affected mainly the respiratory tract, while late-onset sepsis was accompanied by intracranial infection. Therefore, we suggest including a cerebrospinal fluid examination when diagnosing neonatal sepsis. Bacterial genotyping indicated the bacteria were mainly type Ib, Ia, and III S. agalactiae. We recommend treatment with penicillin or ampicillin, since bacteria were resistant to clindamycin and tetracycline. In conclusion, our results provide valuable information for the clinical treatment of S. agalactiae sepsis in neonatal infants.

Aldehyde dehydrogenase 1 activity in the developing human pancreas modulates retinoic acid signalling in mediating islet differentiation and survival

AIMS/HYPOTHESIS

Aldehyde dehydrogenase 1 (ALDH1), a human stem-cell marker, is an enzyme responsible for converting retinaldehydes to retinoic acids (RAs) to modulate cell differentiation. However, data on expression levels and functional roles of ALDH1 during human fetal pancreatic development are limited. The focus of this study was to characterise ALDH1 expression patterns and to determine its functional role in islet cell differentiation.

METHODS

The presence of ALDH1 in the human fetal pancreas (8-22 weeks) was characterised by microarray, quantitative RT-PCR, western blotting and immunohistological approaches. Isolated human fetal islet-epithelial cell clusters were treated with ALDH1 inhibitors, retinoic acid receptor (RAR) agonists and ALDH1A1 small interfering (si)RNA.

RESULTS

In the developing human pancreatic cells, high ALDH1 activity frequently co-localised with key stem-cell markers as well as endocrine transcription factors. A high level of ALDH1 was expressed in newly differentiated insulin(+) cells and this decreased as development progressed. Pharmacological inhibition of ALDH1 activity in human fetal islet-epithelial cell clusters resulted in reduced endocrine cell differentiation and increased cell apoptosis, and was reversed with co-treatment of RAR/RXR agonists. Furthermore, siRNA knockdown of ALDH1A1 significantly decreased RAR expression and induced cell apoptosis via suppression of the phosphoinositide 3-kinase (PI3K) pathway and activation of caspase signals.

CONCLUSIONS/INTERPRETATION

Our findings indicate that ALDH1(+) cells represent a pool of endocrine precursors in the developing human pancreas and that ALDH1 activity is required during endocrine cell differentiation. Inhibition of ALDH1-mediated retinoid signalling impairs human fetal islet cell differentiation and survival.

Critical role of c-Kit in beta cell function: increased insulin secretion and protection against diabetes in a mouse model

AIMS/HYPOTHESIS

The receptor tyrosine kinase, c-Kit, and its ligand, stem cell factor, control a variety of cellular processes, including pancreatic beta cell survival and differentiation as revealed in c-Kit ( Wv ) mice, which have a point mutation in the c-Kit allele leading to loss of kinase activity and develop diabetes. The present study further investigated the intrinsic role of c-Kit in beta cells, especially the underlying mechanisms that influence beta cell function.

METHODS

We generated a novel transgenic mouse model with c-KIT overexpression specifically in beta cells (c-KitβTg) to further examine the physiological and functional roles of c-Kit in beta cells. Isolated islets from these mice were used to investigate the underlying molecular pathway of c-Kit in beta cells. We also characterised the ability of c-Kit to protect animals from high-fat-diet-induced diabetes, as well as to rescue c-Kit ( Wv ) mice from early onset of diabetes.

RESULTS

c-KitβTg mice exhibited improved beta cell function, with significantly improved insulin secretion, and increased beta cell mass and proliferation in response to high-fat-diet-induced diabetes. c-KitβTg islets exhibited upregulation of: (1) insulin receptor and IRSs; (2) Akt and glycogen synthase kinase 3β phosphorylation; and (3) transcription factors important for islet function. c-KIT overexpression in beta cells also rescued diabetes observed in c-Kit ( Wv ) mice.

CONCLUSIONS/INTERPRETATION

These findings demonstrate that c-Kit plays a direct protective role in beta cells, by regulating glucose metabolism and beta cell function. c-Kit may therefore represent a novel target for treating diabetes.

[The experimental study on protective effects and its mechanisms of interleukin-1 receptor antagonist on isolated swine kidney with ischemia/reperfusion]

AIM

To observe the protective effects and approach its mechanisms of interleukin-1 receptor antagonist (IL-1ra) on the isolated swine kidney with ischemia/reperfusion (IR).

METHODS

Thirty two swine were divided randomly into control group (n = 11), IR group (n = 11) and IL-1ra treatment group (IL-1ra group, n = 10) in the study. All swine were electrified. The kidneys were removed and put in ice-box immediately for detecting in control group. In IR group and IL-1ra group, reperfusion pressure and flow rate were both observed once every 30 minutes, the urine at the time of reperfusion 2 hours and the renal cortex at the time of reperfusion 2 hours and 30 minutes were taken for detecting.

RESULTS

The resistance of perfusion in IL-1ra group was much lower than that in the IR group during reperfusion except start of reperfusion, there was a significant difference between IR group and IL-1ra group (P < 0.05, under the same). The content of MDA,TNF-alpha and IL-8 in the renal cortex in IR group were higher and the activities of SOD and Na(+) -K(+) -ATPase were lower than those in control group, In IL-1ra group, the content of MDA and the activity of SOD in renal cortex was respectively higher or lower than that in control group. Compared with IR group, the content of MDA and TNF-alpha and IL-8 in the renal tissues and urine protein were lower and the activities of SOD and Na(+) -K(+) -ATPase were higher in IL-1ra group. The serious degeneration and necrosis of renal tissue were observed in IR group under light microscope and electron microscope, but there was only slight degeneration in IL-1ra group.

CONCLUSION

The results indicated that IL-1ra were effective in protecting the isolated swine kidney from IR injury.

[Expression and characterization of human pulmonary surfactant-associated protein A1 in Saccharomyces cerevisiae]

The cDNA encoding pulmonary surfactant-associated protein A1 (SP-A1) derived from healthy adult's lung was cloned into the pVT102U/alpha, expression vector of Saccharomyces cerevisiae, which contains the yeast alpha-factor signal sequence, leading to the secretion of expressed protein, and then transformed into Saccharomyces cerevisiae S-78 (leu2, ura3, rep4) by electroporation. After 2-3 days culture in adequate pH, the expressed SP-A1 accumulated up to 400 mg/L in supernatant. The pure proteins were obtained by Sephadex G-25, G-75, Sepharose 4B. The expressed recombinant products, 62 kD and 32 kD, reacted to specific antibody using ELISA and Western blot. The SP-A1 protein expressed in Saccharomyces cerevisiae was efficient in enhancing the phagocytosis of E. coli J5 by alveolar macrophages.

Internal atomic distortion and layer roughness of epitaxial SiC thin films studied by short wavelength X-Ray diffraction

Epitaxial silicon carbide thin films grown on a silicon substrate were examined by short wavelength ( 0.71 A from a molybdenum anode) x-ray diffraction to study their atomic distortion and internal layer roughness. Up to 5 order Bragg peaks along (100) were measured and crystallographic structure factors were obtained. Electron density distributions along the surface normal were reconstructed via Fourier transform. In comparing to the ideal situation, it was found that, due to the lattice mismatch, the silicon atoms are no longer fixed on the same atomic plane, thus the corresponding electron distribution maxima were broadened. Also, the maxima for carbon atoms are flattened, indicating the randomized locations.

Spatial stability of extracellular potassium ion and blood flow distribution in rat cerebral cortex after permanent middle cerebral artery occlusion

Extracellular potassium ion activity ([K+]o) increases precipitously during brain ischemia when blood flow falls below threshold values less than approximately 15 mL/100 g/min. This flow threshold for increase of [K+]o occurs also in focal ischemia producing gradient from ischemic core to adjacent normally perfused brain. In this study we investigated the spatial and temporal stability of extracellular potassium ion and blood flow gradients after permanent middle cerebral artery occlusion (MCAO) in rats. [K+]o and regional CBF were measured, respectively, with K+-sensitive and polarographic hydrogen-sensitive microelectrodes at different cortical locations in the middle cerebral artery distribution region. Spatial assessment of [K+]o and regional CBF was conducted at 30, 90, and 180 minutes after MCAO. [K+]o in the more lateral cortex (core) increased from near 3 mmol/L before MCAO to greater than 50 mmol/L and was associated with flow values less than 25% of pre-ischemic levels. Measurements medial to the core (penumbra) indicated progressively decreasing levels of [K+]o and improvement of CBF. There was a tendency for [K+]o in penumbral zones to decrease toward normal levels with time, but there was little dissipation of [K+]o in core regions. In contrast, the spatial CBF profile remained remarkably constant for the entire recording period. Thus, unlike infarction which has been reported to expand with time after focal ischemia, the spatial [K+]o disturbance tends to contract primarily due to decreasing [K+]o with time in the penumbra. Thus, steady state levels of [K+]o after focal ischemia may not be a valuable predictor of cell viability.

Pendelluft flow in symmetric airway bifurcations

We propose a mathematical model for pendelluft flow in a single airway bifurcation. The model is motivated by an apparatus used in an experimental study of the pendelluft by Ultman et al. (1988). We derive differential equations governing the fluid flow, which directly connect physiological parameters to the variables determining the pendelluft; this approach allows us to include nonlinearity in the model. If nonlinearity is neglected, our model is identical to the R-I-C circuits used by previous investigators. If nonlinearity is retained, we show that pendelluft can occur even in perfectly symmetric airway bifurcations. For the specific apparatus used in the experiments of High et al. (1991), we demonstrate that two qualitatively different pendelluft flows can occur in the system.

Oxygen sensitivity of mitochondrial redox status and evoked potential recovery early during reperfusion in post-ischemic rat brain

Inspired oxygen (FiO2) was manipulated during the early reperfusion period after global cerebral ischemia (four-vessel occlusion of 20 or 30 min duration) in anesthetized rats. The goal was to determine whether oxygen availability during the early reperfusion period alters recovery of mitochondrial redox state and evoked electrical activity. The effectiveness of post-ischemic oxygen treatment was monitored at the tissue level with oxygen sensitive microelectrodes, and at the mitochondrial level by reflection spectrophotometry of the redox state of cytochrome oxidase. Transiently decreasing FiO2 from 0.3 to 0.15 limited reperfusion-induced hyperoxygenation and post-ischemic mitochondrial hyperoxidation (PIMHo). Evoked potential recovery was improved by this treatment after 20 min ischemia but not after 30 min ischemia. Increasing FiO2 from 0.3 to 1.0 exacerbated PIMHo and tissue hyperoxygenation. Transient elevation of tissue oxygen tension after 30 min of global ischemia inhibited recovery of evoked potentials. These data suggest that a period of heightened vulnerability to oxidative stress occurs within the first 10 min of reperfusion after global ischemia. This period is characterized by tissue hyperoxygenation and mitochondrial hyperoxidation. Limiting oxygen availability during this period may improve the outcome while conversely elevating oxygenation may be detrimental.

Raman scattering as a characterization tool for epitaxial GaN thin films grown on sapphire by turbo disk metal-organic chemical vapor deposition

Thin layers of GaN, a few micrometers thick, grown on sapphire substrate, are the basic structure in the rapidly developing GaN-based blue optoelectronics devices. We are looking for nondestructive, effective, and convenient characterization tools for GaN/sapphire. Ordinary Raman scattering measurements have limited use because strong Raman signals from the sapphire substrate overwhelm the GaN Raman features. We describe two techniques for making commercial laser Raman systems serve as convenient characterization tools for GaN/sapphire. One uses a near right-angle laser beam incidence, and the other uses microscope lens focusing. In these two ways the detected GaN Raman signals are much stronger than sapphire features, and correct assignments can be made quickly.

Waveguide study and refractive indices of GaN:Mg epitaxial film

Waveguide TE and TM modes in a GaN:Mg epitaxial crystalline film were studied in a wide spectral range (457.9-1053 nm). The refractive indices n(e) and n(o) were accurately determined by TM and TE mode measurements at six different wavelengths (457.9, 514.5, 632.8, 724.3, 855.1, and 1053 nm). Dispersive curves of n(e) versus lambda and no versus lambda were obtained. It was found that bireferingence slightly increases (n(e) - n(o) = 0.033-0.038) from 1053 to 457.9 nm.

Influence of age on the clearance of K+ from the extracellular space of rat hippocampal slices

We examined the hypotheses that aging alters the capacity of brain tissue to regulate extracellular K+ activity (K+o), and that age-related decreases in glucose metabolism may underlie these alterations. Hippocampal slices from young adult (6-9 months old), middle-aged (16-19 months old), and aged (26-29 months old) Fischer 344 rats were exposed to physiological solutions containing 5-20 mM glucose maintained at 36-37 degrees C. Schaffer collaterals in each slice were stimulated at 40 Hz for 2 s, and the resulting changes in K+o were recorded with K+o-sensitive microelectrodes placed in stratum pyramidale of hippocampal subfield CA1. We found that K+ clearance from the extracellular space of hippocampal slices was significantly slowed in the middle-aged group compared with the young adult group in physiological solutions containing 5 and 10 mM glucose. Age-related differences in K+o clearance disappeared in 20 mM glucose. Also, the rate of K+o clearance was modified by glucose concentration. These results suggest that K+ transport rates are modified by age, and that age-related alterations in glucose metabolism may be involved.

Rapid isolation of large amount of plasma VLDL and LDL by a two step ultracentrifugation

A rapid method to obtain large amount of VLDL and LDL by ultracentrifugation is described. The mixture of VLDL and LDL was isolated and concentrated from plasma by an ultracentrifugation at 265 000 g for 2 h. VLDL and LDL were separated and purified by a further ultracentrifugation at 265 000 g for 3 h. This method combines the advantages of both sequential flotation ultracentrifugation and density gradient ultracentrifugation. It can process a large volume of plasma in a short time. The purity of isolated VLDL and LDL was confirmed by the lipoprotein electrophoresis on agarose gel and PAGE and by the apolipoprotein electrophoresis on SDS-PAGE. This rapid economical method is of great value in practical application.

Oxidatively modified very low density lipoprotein enhances monocyte adhesion to endothelial cells

Very los density lipoprotein (VLDL) was incubated with CuCl2(10 mumol/L) at room temperature for 24 hours. The thiobarbituric acid reactive substance (TBARS) was much higher and the electrophoretic mobility was much faster in VLDL after incubation with CuCl2 than that in VLDL without incubation with CuCl2. It demonstrated that VLDL was oxidatively modified by Cu2+. Endothelial cells were pretreated with normal VLDL (N-VLDL) and oxidatively modified VLDL (O-VLDL) and then the adhesion of monocyte to endothelial cells was assayed. We observed that O-VLDL at all the concentrations used enhanced monocyte adhesion to endothelial cells significantly. The results suggest that oxidative modification of VLDL may play a role in the early stage of atherogenesis by increasing monocyte adhesion to endothelial cells.

Mitochondrial hyperoxidation signals residual intracellular dysfunction after global ischemia in rat neocortex

Reperfusion after global ischemia (10-60 min in duration) in rat neocortex most commonly provoked transient hyperoxidation of mitochondrial electron carriers, tissue hyperoxygenation, and CBF hyperemia. These responses were normally accompanied by recovery of K+ homeostasis and EEG spike activity. Goals of this research were to understand putative relationships among these postreperfusion events with special emphasis on determining whether mitochondrial hyperoxidation results from intracellular changes that may modulate residual damage. The amplitude of postischemic mitochondrial hyperoxidation (PIMHo) did not increase when CBF increased above an apparent threshold during reperfusion, and tissue hyperoxygenation was not required for PIMHo to occur or to continue. These findings suggest that PIMHo is not merely a response to increased CBF and tissue hyperoxygenation; rather, PIMHo is modulated, at least in part, by residual intracellular derangements that limit mitochondrial electron transport. This suggestion was supported by observations that NAD became hyperoxidized after reoxygenation in anoxic hippocampal slices. Also, PIMHo occurred and subsequently resolved in many animals, but K+o never was cleared fully to baseline and/or EEG spike activity never was evident. One suggestion is that PIMHo signals or initiates residual intracellular derangements that in turn impair electrical and metabolic recovery of cerebral neurons after ischemia; an alternative suggestion is that PIMHo and tissue hyperoxygenation are not the sole factors modulating the immediate restoration of electrical activity after ischemia. Present data also support the following: Decreased oxygen consumption, despite adequate oxygen delivery, likely contributes to tissue hyperoxygenation after ischemia; and mitochondrial hyperoxidation is modulated by a limitation in the supply of electrons to the mitochondrial respiratory chain.

Photothrombotic infarction triggers multiple episodes of cortical spreading depression in distant brain regions

The purposes of this study were to determine whether cortical spreading depression occurs outside of the infarct produced by photothrombotic vascular occlusion, and also the direction of spreading. Focal cerebral thrombotic infarction was produced by irradiating the exposed skull of anesthetized rats with green light (560 nm) following systemic injection of rose bengal dye. At proximal sites (approximately 2 mm anterior to the infarct border), transient, severe hyperemic episodes (THEs) lasting 1-2 min were intermittently recorded. THE frequency was greatest in the first hour and declined over a 3-h period. THEs were accompanied (and usually preceded) by a precipitous rise in [K+]0 (from approximately 3 to > 40 mM) and were associated with increases in local tissue oxygen tension (tPO2). Following the rise in [K+]0, clearance of [K+]0 to its pre-THE baseline preceded baseline recovery of CBF. These data indicate that THEs were reactive to physiologic events resembling cortical spreading depression (CSD), which provoked increased demand for oxygen and blood flow, and which spread from proximal sites to areas more distal (approximately 4 mm) from the rim of the evolving infarct. MK-801 (1 mg/kg, i.v.) inhibited subsequent CSD-like episodes. We conclude that photothrombosis-induced ischemia provoked CSD which was triggered either within the infarct core or in the infarct rim and spread to more distal sites. Whether multiple episodes of CSD during infarct generation are responsible for the remote consequences of focal brain injury remains to be determined.

Lipoprotein receptor activity of peritoneal macrophages from insulin-deficient mice

Binding, uptake and degradation of 125I-labeled normal very low density lipoprotein (125I-n-VLDL) from normal swine plasma and 125I-labeled beta-migrating VLDL (125I-beta-VLDL) from hypercholesterolemic rabbit plasma by peritoneal macrophages of mice rendered insulin-deficient by streptozotocin (250 mg/kg) were studied. It was found that the amount of binding, uptake and degradation of 125I-n-VLDL by macrophages from the diabetic mice was 2-fold or 2.5-fold higher than by macrophages from normal mice, resulting from an increase in the binding capacity of VLDL receptors on the macrophages from the insulin-deficient rodents. In contrast, the binding, uptake and degradation of 125I-beta-VLDL by macrophages from diabetic mice were reduced to only about 45% of normal levels because of a decrease in the number and affinity of the receptors for beta-VLDL. These experimental results indicate that n-VLDL is more important than beta-VLDL in the pathogenesis of atherosclerosis in insulin-dependent diabetes.

Relationship of VLDL receptor and LPL in metabolism of VLDL by macrophage

Macrophages were incubated with 125I-VLDL for 5 h in presence or absence of lipoprotein lipase (LPL) inhibitor, benzene boronic acid (BBA). Both the uptake and degradation of 125I-VLDL by macrophages were saturable, and the uptake and degradation curves were virtually identical. When macrophages were incubated with 125I-VLDL for 10 h in presence of BBA, the uptake and degradation of 125I-VLDL were still saturable. However, in absence of BBA, the uptake and degradation were no longer saturable. The results suggest that with macrophages incubated with VLDL for a shorter period, VLDL was taken up predominantly via receptor pathway, with a longer period of incubation, LPL played a striking role in uptake of VLDL.

Socioeconomic differences in cardiovascular risk factors in China

Socioeconomic conditions are important in explaining variation in cardiovascular morbidity in advanced societies. To analyse whether cardiovascular risk factors vary according to socioeconomic status in a developing country, and more specifically, in an urban area of China, we compared data from structured interviews and cardiovascular screenings in a group of 1169 male workers (45-65 years). These men participated in the five-year follow-up of a prospective investigation started in 1982/83 in several plants in Wuhan. Unhealthy behaviours such as heavy cigarette smoking and alcohol consumption were significantly more prevalent among men with low educational attainment and with jobs characterized by heavy physical workload, noise and heat. Men paid according to a new, highly demanding salary system exhibited significant increases in total cholesterol and systolic blood pressure from first to second screening. In conclusion, our findings show significant socioeconomic variation in cardiovascular risk factors among middle-aged male workers in China.

Extracellular pH and suppression of electrical activity during anoxia in turtle and rat brain

To evaluate the contribution of extracellular H+ activity toward depression of brain electrical activity during anoxia, extracellular pH (pHe) and field potentials were measured in turtle and rat olfactory bulbs with ion-selective microelectrodes. This study tests the hypothesis that unique regulation of pHe contributes to the remarkable tolerance of turtle brain to prolonged anoxia. Hypercapnea (20% CO2 ventilation) depressed olfactory bulb evoked potentials 25-30% in both rat and turtle. During anoxia, evoked potentials were completely abolished within 1 min in rat olfactory bulb but decreased to only 40% of control after 4 h in the turtle despite similar changes in brain pHe. Anoxia-induced acidification of turtle brain was exacerbated by hypercapnea and was attenuated by hypocapnea or by hypocapnea plus intravenous infusion of sodium bicarbonate. However, these manipulations of pHe during anoxia in turtle brain had little effect on depression of evoked potentials. We conclude that energy failure, rather than extracellular acidification, is the major contributor toward suppression of electrical activity in mammalian brain and that preservation of energy balance, rather than unique pH regulation, is responsible for protection of turtle brain during anoxia.

Energy metabolism, ion homeostasis, and evoked potentials in anoxic turtle brain

Unlike the mammalian brain, the turtle brain maintains ion homeostasis and avoids anoxic depolarization during prolonged anoxia. The mechanisms by which turtle brains avoid and recover from anoxic depolarization were investigated by relating changes in cellular ATP levels to extracellular K+ (K+o) and evoked potential activities after 6 h of anoxia and during anoxic depolarization induced by superfusion of the brain surface with iodoacetate during anoxia. ATP levels were maintained during 6 h of anoxia despite marked decreases in energy production, but ATP was lowered during inhibition of both oxidative phosphorylation and glycolysis. K+o activity was unchanged during 6 h of anoxia but increased when ATP levels decreased. Ion homeostasis in the turtle brain appears to be linked to ATP levels but is unaffected by rate of energy production. In contrast, amplitudes of evoked potentials decreased when ATP levels were maintained, but rate of energy production declined. ATP and K+o levels recovered after anoxic depolarization, but evoked potential activity was not restored. These data suggest that the basic strategy for turtle brain to survive anoxia is to avoid anoxic depolarization by maintaining ATP levels.

Diagnostic and therapeutic hysteroscopy for traumatic intrauterine adhesion. Clinical analysis of 70 patients

This paper presents the results of diagnostic and therapeutic hysteroscopy in 70 patients with traumatic intrauterine adhesions. In all the patients, the diagnoses and types of intrauterine adhesions were confirmed by hysteroscopy. In 68 out of the 70 patients (97.14%) intrauterine adhesions were released successfully after 1-3 times of surgery. Of the 64 patients with amenorrhea or hypomenorrhea before treatment, 54 (84.38%) had regular menstruation. In 35 patients who desired to have a child and were followed up more than 6 months after the withdrawal of contraception, 30 (85.71%) had intrauterine pregnancies. Among the 30 patients, 17 had full-term pregnancies, 12 were in progress and 1 had early spontaneous abortion. The postpartum course was uneventful in the 17 patients with term delivery. We conclude that hysteroscopy is of value in the diagnosis and treatment of traumatic intrauterine adhesions.

The effect of high cholesterol, high fat diet on rabbit plasma beta-VLDL and its interaction with macrophage

Rabbits were fed on 1% cholesterol and 10% rape seed oil (group A) or lard (group B). Plasma cholesterol and triglyceride level of group A was strikingly lower than that of group B. No difference was found in the lipid composition of beta-VLDLs between both groups. However, apo E content of beta-VLDL from group A was higher and apo B (higher molecular weight) was lower than that of group B respectively. beta-VLDL of group A caused greater accumulation of cholesterol in mouse peritoneal macrophage than that of group B. Therefore, we assume that the good effect of poly-unsaturated fatty acid on atherosclerosis results not from decreasing accumulation of cholesterol in macrophages but from enhancing elimination of beta-VLDL by the liver.

The role of lipoprotein lipase in metabolism of normolipidemic very low density lipoprotein by macrophages

It was demonstrated by using lipoprotein lipase (LPL) inhibitor benzene boronic acid (BBA) that LPL played a major role in the accumulation of triglycerides (TG) in mouse peritoneal macrophages exposed to rabbit normal very low density lipoproteins (N-VLDL). There wwere less free fatty acids (FFA) and much more N-VLDL-TG left in the media containing BBA than in the controls. TG accumulation in the cells was greatly diminished or even prohibited by BBA. Thus, we obtained direct evidence that LPL played a more important role than the receptor did in the uptake of N-VLDL-TG by mouse macrophages. The mechanisms of LPL action were discussed.

Metabolism of n-VLDL and beta-VLDL in peritoneal macrophages from diabetic mice

Peritoneal macrophages were harvested from both healthy mice and mice with diabetes induced by intravenous injection of streptozotocin. After incubation with normal plasma very low density lipoprotein (n-VLDL) from swine for 24 h, the content of triglyceride (TG) in macrophages from diabetic mice was higher than that in the controls, and it was the same with the concentration of free fatty acid (FFA) in medium. The basic concentration of cholesterol ester (ChE) in macrophages from diabetic mice was also higher than that of the controls. After incubation with beta-VLDL from hypercholesterolemic rabbit for 48 h, no alteration in ChE content was found in the cells. On the contrary, the content of ChE in the cells from the controls was accumulated by saturating. The levels of FFA in the medium of the diabetic group were still higher than those of the controls. These results demonstrated that the metabolic function of peritoneal macrophages in diabetic mice was altered. The uptake and degradation of n-VLDL and the endogenous cholesterol synthesis were increased, but the uptake of beta-VLDL was lower. In this paper, the possible mechanism and the relationship between atherosclerosis and diabetes are discussed.

Suppression of evoked potentials with continued ion transport during anoxia in turtle brain

A key to turtle brain survival during anoxia is continued ion transport and avoidance of anoxic depolarization. Previous findings that ATP concentration remained constant during prolonged anoxia and calculations that ATP production decreased indicate that compensatory processes, other than consumption of energy stores or increased anaerobic glycolysis, must also contribute to ion homeostasis and brain survival. To determine whether preservation of ion transport is associated with changes in electrophysiology during loss of oxidative metabolism, the brains of pentobarbital sodium-anesthetized turtles were electrically stimulated 1) to provoke measurable increments in extracellular K+ activity (a degrees k) for determination of rates of K+ reaccumulation at the stimulus site and 2) to elicit polysynaptic extracellular field potentials (evoked potentials) recordable in the olfactory bulb. During anoxia, base-line a degrees k rose only a few millimolar, and rates of reaccumulation of K+, incremented by stimulation were slightly but not significantly slowed. In contrast, postsynaptic orthodromic responses of olfactory bulb granule cells were markedly depressed by anoxia. Monosynaptic responses of granule cells to antidromic stimulation of the lateral olfactory tract were less affected, and compound action potentials in the olfactory nerve were unchanged by anoxia. These data suggest that synaptic transmission in turtle brain, as in that of mammal, is highly dependent on oxidative metabolism and that the turtle brain may effectively conserve energy for ion transport during anoxia by depression of electrical activity.

Orthodromic field potentials and recurrent inhibition during anoxia in turtle brain

Recent evidence suggests that suppression of electrical activity, with the likely reduction of energy use, provides a necessary strategy for prolonged anoxic tolerance of turtle brain. The present study was aimed toward defining mechanisms underlying anoxia-induced suppression of electrical activity in turtle brain. Goals were to determine whether effects of anoxia were selective to excitatory or inhibitory processes and to test the hypothesis that enhanced inhibition underlies suppression of orthodromic field potentials in olfactory bulb. Amplitudes of "conditioning" and "test" responses, provoked by pairs of stimulus pulses to the olfactory nerve, were evaluated before, during, and after anoxic insults in the brains of turtles anesthetized with pentobarbital sodium. Suppression of conditioning responses was proportionally greater than that of test responses, indicating that inhibition was decreased and that enhanced inhibitory activity is not responsible for suppression of field potentials in turtle olfactory bulb during anoxia. When normoxia was restored, conditioning responses recovered but test responses remained suppressed. These data confirm that the inhibitory effect of a conditioning pulse on responses to a second pulse of stimulation results from a recurrent circuit and suggest that anoxia-induced changes in field potentials are independent of this recurrent circuit. Enhanced inhibition during the early period of recovery after anoxic insults may provide advantages for restoring energy status and cell physiology by suppressing electrical activity and energy use.

Depth profile of local oxygen tension and blood flow in rat cerebral cortex, white matter and hippocampus

Microregional oxygenation and blood flow were measured in rat cerebral cortical lamina, subcortical white matter and hippocampus. This was done to examine relationships between oxygenation and blood flow at a local level, to determine effects of craniotomy, and to consider whether flow/oxygenation relationships might be predictive of selective vulnerability known to accompany anoxia or ischemia. Blood flow and oxygen tension were measured with closely apposed polarographic microelectrodes. Oxygen tension was highest in white matter, lower in the region of cortical laminae IV-V and lowest in the hippocampus. Blood flow in the hippocampus was higher than that in white matter or laminae IV-V of cerebral cortex. Ratios of blood flow to oxygenation were similar throughout the cortex, higher in white matter but oxygenation in hippocampus was significantly less than expected from measurement of hippocampal blood flow reflecting increased oxygen consumption or relative hypoxia due to increased diffusion distances for oxygen in hippocampus. Comparison of data from closed vs opened skull animals indicated that diffusion of oxygen and hydrogen influenced data to approximately 1000 micron below the cerebral surface.

Immunoglobulin allotypes in a Chinese population: comparison of haplotype frequencies with other Asian groups

Two groups of Chinese individuals of the city of Wuhan in the People's Republic of China, consisting of 98 blood bank donors and 278 workers in a steel factory, respectively, have been typed for G1m, G2m, G3m, A2m and Km allotypes. The Gm-A2m haplotype frequencies as well as the Km gene frequencies appeared to be quite similar in these two groups of people, the main haplotypes being Gmaf;n;b A2m2 and Gmza;..;g A2m1. After joining the data of the two groups, the frequencies of the main Gm haplotypes and the A2m and Km gene frequencies have been compared with those of six other Asian populations. In Asia, going from the south to the north, an increasing frequency of Gmza;..;g and a decreasing frequency of Gmaf;n;b were observed. The frequencies found in the investigated Chinese population lie between the frequencies found in the Chinese from Taiwan and the Japanese.

Very low density lipoproteins promote triglyceride accumulation in macrophages

Incubation of mouse peritoneal macrophages with very low density lipoproteins (VLDL) from normal rats or rhesus monkeys markedly increased the levels of intracellular triglycerides by 10- to 56-fold and was accompanied by the production of oil red O positive vacuoles. The stimulation of triglyceride accumulation in macrophages was time- and concentration-dependent and was specific for VLDL. Three possible mechanisms for the VLDL-stimulated triglyceride accumulation in macrophages were explored: receptor-mediated uptake, action of lipoprotein lipase, and phagocytosis. Macrophage uptake and degradation of 125I-monkey and rat VLDL demonstrated saturable and nonsaturable components. Uptake of 125I-VLDL could be inhibited by unlabeled normal VLDL, although hyperlipemic VLDL was more effective. HDL did not compete to a significant extent. Heparin released lipoprotein lipase-like activity from peritoneal macrophages. Addition of heparin with VLDL resulted in a greater, more rapid elevation in intracellular triglycerides, which was partially inhibited by albumin. Free fatty acid and Intralipid also produced triglyceride accumulation in macrophages. The data showed that all three of the mechanisms examined could contribute to the metabolism of VLDL by macrophages and cause the production of triglyceride-rich cells with a "foamy" appearance, although the evidence suggested that the action of lipoprotein lipase was probably the most important in this process.