[Properties of gelatin-polyethylene glycol hydrogel loaded with silver nanoparticle Chlorella and its effects on healing of infected full-thickness skin defect wounds in mice]

Objective: To explore the properties of gelatin-polyethylene glycol hydrogel loaded with silver nanoparticle (AgNP) Chlorella (hereinafter referred to as the composite hydrogel) and its effects on healing of infected full-thickness skin defect wounds in mice. Methods: The research was an experimental research. The simple gelatin-polyethylene glycol hydrogel (hereinafter referred to as the simple hydrogel) and the composite hydrogel were prepared, and the appearance and injectability of the two hydrogels were observed at 55 and 37 ℃, and under the irradiation of 808 nm near-infrared light, respectively. An electronic universal testing machine was employed to assess the tensile and compressive stress-strain properties of both types of hydrogels at room temperature. Additionally, the cyclic compressive stress-strain properties of the composite hydrogel were examined at 80% of the maximum compressive stress. Staphylococcus aureus or Escherichia coli solution was added to phosphate buffer solution (PBS), simple hydrogel, and composite hydrogel, respectively. The part of composite hydrogel containing Staphylococcus aureus or Escherichia coli solution was irradiated with near-infrared light for 5 minutes. After each sample was incubated for 6 h, the dilution plating method was used to detect and calculate the mortality rates of the two bacteria at 24 h of culture (n=5). The discarded foreskin tissue was taken from a 6-year-old healthy boy admitted to the Department of Urology of the First Affiliated Hospital of Naval Medical University for circumcision. Primary human fibroblasts (HFbs) were isolated using the enzyme extraction method, routinely cultured to the 3rd to 6th passages for subsequent cellular experiments. Composite hydrogel extracts with final mass concentrations of 100.0, 50.0, 25.0, 12.5, and 0 mg/mL were respectively prepared and used to culture HFbs, and the cell proliferation after 24 h of culture was detected using a cell counting kit 8 (n=3). A total of twenty 6-8 weeks old C57BL/6J female mice were utilized, and a full-thickness skin defect was surgically created on the back of each mouse. The wounds were infected with Staphylococcus aureus solution. The infected mice were divided into blank control group, simple hydrogel group, composite hydrogel group, and combined treatment group according to the random number table, and the wounds were treated with PBS, simple hydrogel, composite hydrogel, and composite hydrogel+light irradiation (under the irradiation of 808 nm near-infrared light for 5 min), respectively, with 5 mice in each group. On post injury day (PID) 0 (immediately after the first wound treatment), 3, 7, and 14, an overall assessment of wound exudation and healing were conducted, and the wound healing rates on PID 7 and 14 were calculated (n=5). On PID 14, hematoxylin-eosin staining was performed to observe histopathological changes in the mouse wound. Results: Both simple hydrogel and composite hydrogel were in a solution state at 55 ℃ and transition to a gel state when cooling to 37 ℃. After the two hydrogels were irradiated by near-infrared light, only the composite hydrogel reheated up and returned to the solution state again with injectability. The maximum tensile stress of the composite hydrogel was up to 301.42 kPa, with a corresponding strain of 87.19%; the maximum compressive stress was up to 413.79 kPa, with a corresponding strain of 91.67%, which was similar to the tensile and compressive properties of the simple hydrogel. After 10 compression cycles, the maximum compressive stress of the composite hydrogel still reached 84.1% of the first compressive stress. After 24 h of culture, the mortality rate of Staphylococcus aureus treated with simple hydrogel was significantly higher than that treated with PBS (P<0.05); the mortality rates of Escherichia coli and Staphylococcus aureus treated with composite hydrogel alone were significantly higher than those treated with simple hydrogel (P<0.05); the mortality rates of Escherichia coli and Staphylococcus aureus treated with composite hydrogel+light irradiation were significantly higher than those treated with composite hydrogel alone (P<0.05). After 24 h of culture, compared with that cultured in composite hydrogel immersion solution with final mass concentration of 0 mg/mL, the proliferation activity of HFbs cultured in composite hydrogel immersion solution with final mass concentrations of 25.0 and 50.0 mg/mL was significantly enhanced (P<0.05), while the proliferation activity of HFbs cultured in composite hydrogel immersion solution with final mass concentration of 100 mg/mL was significantly decreased (P<0.05). On PID 0 and 3, more purulent secretions were seen in the wounds of mice in blank control group and simple hydrogel group, while only a small amount of exudate was observed in the wounds of mice in composite hydrogel group, and no obvious infection was observed in the wounds of mice in combined treatment group. On PID 7 and 14, the wound healing rates of mice in simple hydrogel group were significantly higher than those in blank control group (P<0.05); the wound healing rates of mice in composite hydrogel group were significantly higher than those in simple hydrogel group (P<0.05); the wound healing rates in combined treatment group were significantly higher than those in composite hydrogel group (P<0.05). On PID 14, the wounds of mice in blank control group exhibited a high infiltration of inflammatory cells with no new epithelial layer observed; the wounds of mice in simple hydrogel group displayed a short length of newly formed epithelium with a small amount of inflammatory cells; the wounds of mice in composite hydrogel group exhibited continuous formation of new epithelium and a large amount of immature granulation tissue; the wounds of mice in combined treatment group showed continuous epithelialization with less immature granulation tissue. Conclusions: The prepared composite hydrogel exhibits excellent thermosensitivity, photothermal properties, and injectability, as well as excellent mechanical properties, antibacterial properties, and biocompatibility, and can promote the healing of infected full-thickness skin defect wounds in mice.

Endoscopic palliative resection of a giant 26-cm esophageal tumor: A case report

BACKGROUND

Esophageal carcinosarcoma, usually presenting as a pedunculated polypoid mass, is a rare malignancy with coexisting sarcomatoid and carcinomatous components. Its imaging and endoscopic characteristics are similar to those of leiomyosarcoma, liposarcoma and so forth. The diagnosis needs histological confirmation. Surgical resection is the traditional therapy. Endoscopic resection is minimally invasive but still controversial. This paper reports the case of a patient with a giant esophageal carsinosarcoma who underwent a palliative endoscopic resection.

CASE SUMMARY

A 55-year-old male patient presented with dysphagia and weight loss for 1 mo. Imaging and endoscopy showed a gray-white, polypoid, stalk-like mass, with a bulky pedicle located in the middle and lower esophagus. The mass almost filled the whole esophageal lumen, but the endoscope could still pass through. Despite the suspicion of a malignancy, repeated biopsies indicated necrosis and inflammation. After multidisciplinary team consultation, an endoscopic resection to diagnose and relieve the obstruction was recommended. The pedicle of the mass was cut off, the bleeding was stopped, and the mass was cut into pieces and pulled out. The mass was 26 cm × 5 cm × 4 cm in size. The final diagnosis was esophageal carcinosarcoma. No postoperative complications occurred. After 1 mo, the patient gained 6 kg and endoscopic reexamination revealed no obstruction. Radical surgery with lymph node dissection was carried out successfully. This lesion was the largest endoscopically resected esophageal carcinosarcoma reported to date.

CONCLUSION

Endoscopic palliative resection can help obtain adequate tissue for diagnosis and relieve obstructions in patients with giant esophageal carcinosarcoma.

[Current situation and related policies on the implementation and promotion of influenza vaccination among health care workers]

Health care workers have higher risk of influenza infection because of their occupational exposure to infected patients. Infection of the health care workers may not only result in the increasing risk of the nosocomial infection and family transmission, but also disrupt the health services due to absence from work. Health care workers were recommended as a priority group of influenza vaccinationin more than 40 countries and regions in the world. In recent years, domestic surveys show that the influenza vaccine coverage among health care workers was low. This paper outlines the current status and related policies of influenza vaccination among health care workers in China and global. Additionally, we analyzed and discussed the proper immunization strategy of influenza vaccine for medical staff in China.

Consensus on the digestive endoscopic tunnel technique

With the digestive endoscopic tunnel technique (DETT), many diseases that previously would have been treated by surgery are now endoscopically curable by establishing a submucosal tunnel between the mucosa and muscularis propria (MP). Through the tunnel, endoscopic diagnosis or treatment is performed for lesions in the mucosa, in the MP, and even outside the gastrointestinal (GI) tract. At present, the tunnel technique application range covers the following: (1) Treatment of lesions originating from the mucosal layer, e.g., endoscopic submucosal tunnel dissection for oesophageal large or circular early-stage cancer or precancerosis; (2) treatment of lesions from the MP layer, per-oral endoscopic myotomy, submucosal tunnelling endoscopic resection, etc.; and (3) diagnosis and treatment of lesions outside the GI tract, such as resection of lymph nodes and benign tumour excision in the mediastinum or abdominal cavity. With the increasing number of DETTs performed worldwide, endoscopic tunnel therapeutics, which is based on DETT, has been gradually developed and optimized. However, there is not yet an expert consensus on DETT to regulate its indications, contraindications, surgical procedure, and postoperative treatment. The International DETT Alliance signed up this consensus to standardize the procedures of DETT. In this consensus, we describe the definition, mechanism, and significance of DETT, prevention of infection and concepts of DETT-associated complications, methods to establish a submucosal tunnel, and application of DETT for lesions in the mucosa, in the MP and outside the GI tract (indications and contraindications, procedures, pre- and postoperative treatments, effectiveness, complications and treatments, and a comparison between DETT and other operations).

[DS2, a newly synthetic ent-kaurane diterpenoid analog, inhibits proliferation and migration of human gastric cancer cell]

Objective: To investigate the effects and the underlying mechanism of DS2, a newly synthetic analog of natural ent-kaurane diterpenoid, on the proliferation and migration capabilities of human gastric cancer cells. Methods: MTT assay, colony formation assay and flow cytometry were used to measure the effects of DS2 on growth, apoptosis and cell cycle of several human gastric cancer cell lines. The function of DS2 in the migration was further detected by wound healing and transwell assays. The expression of migration related proteins were determined by western blot. Results: DS2 inhibited the growth of MGC-803, SGC-7901 and HGC-27 cells in a dose dependent manner. After treatment of DS2 at a concentration of 6.25 μmol/L for 24 h, the survival rates of MGC-803, SGC-7901 and HGC-27 cells were 53.87±3.05%, 55.91±6.97% and 32.41±2.64%, respectively. However, for the normal gastric epithelial cell GES-1, no obvious growth inhibition was observed. In addition, DS2 caused significant G(2)/M arrest and induced apoptosis in MGC-803 cells. Furthermore, compared with the negative control, the colony formation, wound healing rate as well as the number of migrating cells of MGC-803 were significantly decreased in a dose dependent manner after DS2 treatment. DS2 induced the expression of E-cadherin, whereas β-catenin and N-cadherin levels were downregulated in MGC-803. Conclusion: The new compound DS2 has a strong anti-cancer activity, and this study will help us to design and synthesize better diterpenoids derivatives.

[Effects of acute hypoxia on telomere length of rat gastric mucosa tissue and underlying mechanism]

The present study was aimed to investigate the effect of acute hypoxia on telomere length of rat gastric mucosa tissue and possible mechanism. Forty male Wistar rats were randomly divided into control group (resided in Lanzhou, 1 500 m) and experimental group (hypoxia chamber, 5 000 m). The experimental group was further divided into 3 subgroups and exposed to hypoxia for 1, 3, 7 d (n = 10), respectively. The morphological changes of the gastric mucosa tissue were observed by HE staining. By means of real-time PCR, ELISA and chemical immunofluorescence methods, the telomere length, the mRNA and protein levels of telomerase reverse transcriptase (TERT), hypoxia-inducible factor 1α (HIF-1α) and HIF-2α, and reactive oxygen species (ROS) level in gastric mucosa tissue were measured, respectively. The results showed that, with the extension of hypoxia-exposure time, the injury in gastric mucosa cells progressively became worse, and telomere length was increased gradually, along with intracellular ROS generation. The changes of TERT and HIF-1α expressions induced by acute hypoxia were in the same trend as that of telomere length. There were positive correlations between TERT mRNA expression and telomere length and between TERT and HIF-1α expressions, but not between TERT and HIF-2α mRNA expressions. These results suggest that under acute severe hypoxia environment, ROS could damage the gastric mucosa tissue cells, meanwhile the expressions of TERT and telomerase activity may be up-regulated by HIF-1α, which can elongate the telomere length and protect gastric mucosa tissue against fatal injury.

[Jaridonin, a new diterpenoid from Isodon rubescens, induces cell cycle arrest in gastric cancer cells through activating ataxia telangiectasia mutated kinase]

OBJECTIVE

To study the effects of Jaridonin, a novel diterpenoid from isodon rubescens, on the cell cycle of human gastric cancer cells and its molecular mechanism of action.

METHODS

Flow cytometry was used to analyze the cell cycle distribution and expression of ataxia telangiectasia mutated kinase (ATM) after Jaridonin treatment. Western blot was performed to detect the expression of cell cycle-related proteins.

RESULTS

The results of flow cytometry showed that the percentages of MGC-803 cells in G(2)/M phase at 6 hours after 0, 10, 20 μmol/L Jaridonin-treatment were (10.8±2.2)%, (18.2±2.5)%, (27.3±3.2)%, respectively; those at 12 hours after Jaridonin-treatment were (12.0±1.5)%, (24.1±2.0)% and (39.7±5.2)%, respectively, indicating a G2/M phase arrest of MGC-803 cells was resulted in a time- and dose-dependent manner. The expressions of ATM, Chk1, Chk2, phosphorylated Cdc2 and CDK2 were up-regulated in the MGC-803 cells after Jaridonin treatment, while the levels of Cdc2 and CDK2 were decreased. KU-55933, an inhibitor of ATM, reversed the expression of relevant proteins and G(2)/M phase arrest induced by Jaridonin.

CONCLUSIONS

Jaridonin can significantly induce G(2)/M arrest in gastric cancer MGC-803 cells. Its mechanism may be related to the activation of ATM and Chk1/2, and inactivation of Cdc2 and CDK2 phosphorylation.

Mesalazine in combination with Danshen injection for treatment of ulcerative colitis: Curative efficacy and effect on inflammatory factors and coagulation parameters

AIM: To investigate the clinical effects of mesalazine in combination with Danshen injection in the treatment of ulcerative colitis (UC) and its effects on inflammatory factors and coagulation parameters.

METHODS: One hundred cases of UC treated at our hospital from January 2013 to December 2014 were included and randomly divided into two groups equally. Besides conventional treatments, the control group was additionally given mesalazine, while the observation group was additionally given mesalazine in combination with Danshen injection. The curative efficacy, levels of inflammatory factors and coagulation parameters were compared. After 6-month follow-up, recurrence rates of UC between the two groups were compared. Adverse reactions were also observed and compared.

RESULTS: The total response rate of the observation group was statistically higher than that of the control group (94.5% vs 80.0%, P < 0.05). In comparison with the control group after treatment, tumor necrosis factor α (TNF-α), interleukin (IL)-6, and IL-8 in the observation group were statistically lower (P < 0.05 for all). As to coagulation parameters, in comparison with the control group after treatment, the observation group had statistically lower levels of plasma fibrinogen (FIB), platelet count (PLT) and higher level of mean platelet volume (MPV) (P < 0.05 for all). At the 6-month follow-up, the recurrence rate of UC in the observation group was statistically lower than that in the control group (5.4% vs 20.0%, P < 0.05). During the treatment, incidence of adverse reactions in the observation group and the control group was 10.9% and 7.3%, respectively, with no statistical difference (P > 0.05).

CONCLUSION: Combined treatment of mesalazine and Danshen injection is effective for UC, which can significantly increase curative efficacy, alleviate inflammatory reaction, improve coagulation parameters and decrease recurrence rate with minor adverse reactions.

Differential gene expression profiling of gastric intraepithelial neoplasia and early-stage adenocarcinoma

AIM: To investigate the differentiated whole genome expression profiling of gastric high- and low-grade intraepithelial neoplasia and early-stage adenocarcinoma.

METHODS: Gastric specimens from an upper magnifying chromoendoscopic targeted biopsy were collected from March 2010 to May 2013. Whole genome expression profiling was performed on 19 low-grade intraepithelial neoplasia (LGIN), 20 high-grade intraepithelial neoplasia (HGIN), 19 early-stage adenocarcinoma (EGC), and 19 chronic gastritis tissue samples using Agilent 4 × 44K Whole Human Genome microarrays. Differentially expressed genes between different types of lesions were identified using an unpaired t-test and corrected with the Benjamini and Hochberg false discovery rate algorithm. A gene ontology (GO) enrichment analysis was performed using the GeneSpring software GX 12.6. The differentially expressed gene was verified using a real-time TaqMan^® PCR assay with independent tissue samples, including 26 LGIN, 15 HGIN, 14 EGC, and 20 chronic gastritis. The expression of G₀S₂ were further validated by immunohistochemical staining (IHC) in 24 LGIN, 40 HGIN, 30 EGC and 61 chronic gastritis specimens.

RESULTS: The gene expression patterns of LGIN and HGIN tissues were distinct. There were 2521 significantly differentially expressed transcripts in HGIN, with 951 upregulated and 1570 downregulated. A GO enrichment analysis demonstrated that the most striking overexpressed transcripts in HGIN compared with LGIN were in the category of metabolism, defense response, and nuclear factor κB (NF-κB) cascade. While the vast majority of transcripts had barely altered expression in HGIN and EGC tissues, only 38 transcripts were upregulated in EGC. A GO enrichment analysis revealed that the alterations of the immune response were most prominent in the progression from HGIN to EGC. It is worth noting that, compared with LGIN, 289 transcripts were expressed at higher levels both in HGIN and EGC. A characteristic gene, G₀/G₁ switch 2 (G₀S₂) was one of the 289 transcripts and related to metabolism, the immune response, and the NF-κB cascade, and its expression was validated in independent samples through real-time TaqMan^® PCR and immunohistochemical staining. In real-time PCR analysis, the expression of G₀S₂ was elevated both in HGIN and EGC compared with that in LGIN (P < 0.01 and P < 0.001, respectively). In IHC analysis, G₀S₂ immunoreactivity was detected in the cytoplasmic of neoplastic cells, but was undetectable in chronic gastritis cells. The G₀S₂ expression in HGIN was higher than that of LGIN (P = 0.012, χ² = 6.28) and EGC (P = 0.008, χ² = 6.94).

CONCLUSION: A clear biological distinction between gastric high- and low-grade intraepithelial neoplasia was identified, and provides molecular evidence for clinical application.

Clinical epidemiology of gastric cancer in Hehuang valley of China: A 10-year epidemiological study of gastric cancer

AIM: To investigate the clinical epidemiological characteristics of gastric cancer in the Hehuang valley, China, to provide a reference for treatment and prevention of regional gastric cancer.

METHODS: Between February 2003 and February 2013, the records of 2419 patients with gastric cancer were included in this study. The patient’s characteristics, histological and pathological features, as well as the dietary habits of the patients, were investigated.

RESULTS: The clinical data showed that adenocarcinoma was the leading histological type of gastric cancer in this area. Characteristics of gastric cancer in different ethnic groups and age showed that the 60.55-65.50 years group showed the high incidence of gastric cancer in all ethnic groups. There were more male gastric cancer patients than female. Intestinal was the most common type of gastric cancer in the Hehuang valley. There was no significant difference in the proportion of sex in terms of Helicobacter pylori infection. The impact of dietary habits on gastric cancer showed that regular consumption of fried or grilled food, consumption of high-salt, high-fat and spicy food and drinking strong Boiled brick-tea were three important factors associated with gastric cancer in males and females.

CONCLUSION: Differences existed in race, sex, and age of patients according to the epidemiology of gastric cancer in the Hehuang valley. Moreover, dietary habits was also an important factor contributing to gastric cancer.

Out-of-plane temperature-dependent resistivity studies on Tl-based superconductors

Temperature-dependent resistivities in the ab-plane and c-axis of Tl-based cuprates have been measured. Unlike the ab-plane properties, which are metallic, c-axis transport is semiconductor-like in the normal state for Tl(2)Ba(2)Ca(2)Cu(3)O(x) (Tl-2223) and Tl(2)Ba(2)CaCu(2)O(x) (Tl-2212). In contrast, for Tl(2)Ba(2)CuO(x) (Tl-2201), transport is metal-like in both the in-plane and the c-axis. For multi-layered cuprates, transport properties along the c-axis could be described by a tunnelling model, whereas for single-layered compound Tl-2201 it would be easier for the out-of-plane transport behaviour to be coherent since the there are no insulating Ca layers in its structure. Moreover, combining the studies on Bi-2201, which has an insulating behaviour for the out-of-plane resistivity, we suggest that the Tl-O layers in Tl-based superconductors could be conducting, unlike the weakly correlated Bi-O layers in Bi-based cuprates.

Infrared probe of the electronic structure and charge dynamics of Na0.7CoO2

We present measurements of the optical spectra on Na(0.7)CoO(2) single crystals. The optical conductivity shows two broad interband transition peaks at 1.6 eV and 3.1 eV, and a weak midinfrared peak at 0.4 eV. The intraband response of conducting carriers is different from that of a simple Drude metal. A peak at low but finite frequency is observed, which shifts to higher frequencies with increasing temperature, even though the dc resistivity is metallic. The origin of the interband transitions and the low-frequency charge dynamics have been discussed and compared with other experiments.

Low-dose alemtuzumab (Campath®) in myeloablative allogeneic stem cell transplantation for CD52-positive malignancies: decreased incidence of acute graft-versus-host-disease with unique pharmacokinetics

Alemtuzumab is effective in reducing the risk of acute graft-versus-host disease (GVHD) after allogeneic stem cell transplantation (ASCT). Alemtuzumab may also delay immune reconstitution and reduce graft-versus-leukemia effects. The optimal dose has not been established. We investigated engraftment, acute GVHD incidence and severity, and pharmacokinetics of alemtuzumab associated with the use of low-dose alemtuzumab/cyclophosphamide/total body irradiation and ASCT for patients with aggressive CD52-positive hematologic malignancies. In all, 12 patients were treated. Alemtuzumab 10 mg daily on days -7 to -3 was given intravenously. Tacrolimus and methotrexate were used for GVHD prophylaxis. Alemtuzemab was not detected in any of the 36 sequential serum samples tested between days -1 and +21 of transplant. All patients engrafted rapidly; the median time to an absolute neutrophil count >0.5 x 10(9)/l was 14 days (range 11-17 days), and the median time to a platelet count >20 x 10(9)/l was 16 days (range 6-30 days). By 1 month after transplant, nine patients had 100% donor chimerism, while three had mixed donor chimerism. At 3 months, 11 had achieved 100% donor chimerism. No cases of grade III/IV acute GVHD occurred. At a median follow-up interval of 14.7 months (range 4-24), seven patients remained alive, and five remained free of disease.

Novel regulation and function of Src tyrosine kinase

Src tyrosine kinase is a critical signal transducer that modulates a wide variety of cellular functions. Misregulation of Src leads to cell transformation and cancer. Heterotrimeric guanine-nucleotide-binding proteins (G proteins) are another group of signaling molecules that transduce signals from cell-surface receptors to generate physiological responses. Recently, it was discovered that G alpha s and G alpha i could directly stimulate Src family tyrosine kinase activity. This novel regulation of Src tyrosine kinase by G proteins provides insights into the adenylyl cyclase-independent signaling mechanisms involved in ligand-induced receptor desensitization, internalization and other physiological processes.

RGS-PX1, a GAP for GalphaS and sorting nexin in vesicular trafficking

Heterotrimeric GTP-binding proteins (G proteins) control cellular functions by transducing signals from the outside to the inside of cells. Regulator of G protein signaling (RGS) proteins are key modulators of the amplitude and duration of G protein-mediated signaling through their ability to serve as guanosine triphosphatase-activating proteins (GAPs). We have identified RGS-PX1, a Galpha(s)-specific GAP. The RGS domain of RGS-PX1 specifically interacted with Galpha(s), accelerated its GTP hydrolysis, and attenuated Galpha(s)-mediated signaling. RGS-PX1 also contains a Phox (PX) domain that resembles those in sorting nexin (SNX) proteins. Expression of RGS-PX1 delayed lysosomal degradation of the EGF receptor. Because of its bifunctional role as both a GAP and a SNX, RGS-PX1 may link heterotrimeric G protein signaling and vesicular trafficking.

Urinary thiodiglycolic acid levels for vinyl chloride monomer-exposed polyvinyl chloride workers

Thiodiglycolic acid (TdGA) is the major metabolite of vinyl chloride monomer (VCM) detected in human urine. Although urinary TdGA has been reported to be associated with ambient VCM exposure, the relationship between urinary TdGA and a low level of air VCM is not clear. Questionnaires were administered to 16 polyvinyl chloride manufacturing workers to obtain a detailed history of occupation and lifestyle. For each worker, personal air monitoring for VCM was performed and a time-weighted average for VCM exposure was calculated. The urinary TdGA levels at the end of a work shift, and at the commencement of the next shift, were also assessed for each worker. Urine analysis revealed that TdGA levels at the beginning of the next shift were higher than those at the end of that shift. Workers experiencing a VCM exposure greater than 5 ppm in air revealed a urinary TdGA level significantly greater than those experiencing a VCM exposure of less than 5 ppm (P < 0.05). The best fit of regression for urinary TdGA on air VCM was Y = 1.06 + 0.57X for urine collected at the commencement of the following work shift, where X is the air VCM concentration and Y is the urinary TdGA concentration (r2 = 0.65, P < 0.01). We conclude that the urinary TdGA level is best detected at the commencement of the next shift and that it can be used as an exposure marker for polyvinyl chloride workers when the air VCM level to which they are exposed is greater than 5 ppm.

Src tyrosine kinase is a novel direct effector of G proteins

Heterotrimeric G proteins transduce signals from cell surface receptors to modulate the activity of cellular effectors. Src, the product of the first characterized proto-oncogene and the first identified protein tyrosine kinase, plays a critical role in the signal transduction of G protein-coupled receptors. However, the mechanism of biochemical regulation of Src by G proteins is not known. Here we demonstrate that Galphas and Galphai, but neither Galphaq, Galpha12 nor Gbetay, directly stimulate the kinase activity of downregulated c-Src. Galphas and Galphai similarly modulate Hck, another member of Src-family tyrosine kinases. Galphas and Galphai bind to the catalytic domain and change the conformation of Src, leading to increased accessibility of the active site to substrates. These data demonstrate that the Src family tyrosine kinases are direct effectors of G proteins.

Apoptotic signaling through the beta -adrenergic receptor. A new Gs effector pathway

Stimulation of beta-adrenergic receptor normally results in signaling by the heterotrimeric G protein G(s), leading to the activation of adenylyl cyclase, production of cAMP, and activation of cAMP-dependent protein kinase (PKA). Here we report that cell death of thymocytes can be induced after stimulation of beta-adrenergic receptor, or by addition of exogenous cAMP. Apoptotic cell death in both cases was observed with the appearance of terminal deoxynucleotidyl transferase-mediated UTP end labeling reactivity and the activation of caspase-3 in S49 T cells. Using thymocytes deficient in either Galpha(s) or PKA, we find that engagement of beta-adrenergic receptors initiated a Galpha(s)-dependent, PKA-independent pathway leading to apoptosis. This alternative pathway involves Src family tyrosine kinase Lck. Furthermore, we show that Lck protein kinase activity can be directly stimulated by purified Galpha(s). Our data reveal a new signaling pathway for Galpha(s), distinct from the classical PKA pathway, that accounts for the apoptotic action of beta-adrenergic receptors.

Identification of the binding site for Gqalpha on its effector Bruton's tyrosine kinase

Heterotrimeric G proteins and tyrosine kinases are two major cellular signal transducers. Although G proteins are known to activate tyrosine kinases, the activation mechanism is not clear. Here, we demonstrate that G protein Gqalpha binds directly to the nonreceptor Bruton's tyrosine kinase (Btk) to a region composed of a Tec-homology (TH) domain and a sarcoma virus tyrosine kinase (Src)-homology 3 (SH3) domain both in vitro and in vivo. Only active GTP-bound Gqalpha, not inactive GDP-bound Gqalpha, can bind to Btk. Mutations of Btk that disrupt its ability to bind Gqalpha also eliminate Btk stimulation by Gqalpha, suggesting that this interaction is important for Btk activation. Remarkably, the structure of this TH (including a proline-rich sequence) -SH3 fragment of the Btk family of tyrosine kinases shows an intramolecular interaction. Furthermore, the crystal structure of the Src family of tyrosine kinases reveals that the intramolecular interaction of SH3 and its ligand is the major determining factor keeping the kinase inactive. Thus, we propose an activation model that entails binding of Gqalpha to the TH-SH3 region, thereby disrupting the TH-SH3 intramolecular interaction and activating Btk.

Effect of docosahexaenoic acid on the synthesis of phosphatidylserine in rat brain in microsomes and C6 glioma cells

Docosahexaenoic acid (22:6n-3) is the major polyunsaturated fatty acid (PUFA) in the CNS and accumulates particularly in phosphatidylserine (PS). We have investigated the effect of the 22:6n-3 compositional status on the synthesis of PS. The fatty acid composition of brain microsomes from offspring of rats artificially reared on an n-3-deficient diet showed a dramatic reduction of 22:6n-3 content (1.7 +/- 0.1%) when compared with control animals (15.0 +/- 0.2%). The decrease was accompanied by an increase in docosapentaenoic acid (22:5n-6) content, which replaced the 22:6n-3 phospholipids with 22:5n-6 molecular species, as demonstrated using HPLC/electrospray mass spectrometry. The n-3 deficiency did not affect the total amount of polyunsaturated phospholipids in brain microsomes; however, it was associated with a decrease in the total polyunsaturated PS content and with increased levels of 1-stearoyl-2-docosapentanoyl (18:0/22:5n-6) species, particularly in phosphatidylcholine. Incorporation of [3H]serine into PS in rat brain microsomes from n-3-deficient animals was slightly but significantly less than that of the control animals. Similarly, C6 glioma cells cultured for 24 h in 22:6n-3-supplemented media (10-40 microM) showed a significant increase in the synthesis of [3H]PS when compared with unsupplemented cells. Our data show that neuronal and glial PS synthesis is sensitive to changes in the docosahexaenoate levels of phospholipids and suggest that 22:6n-3 may be a modulator of PS synthesis.

[Effect of norepinephrine on the thermosensitive neurons in preoptic area of hypothalamus tissue slices in cold acclimatized rats]

In this work, single unit firing activities were recorded in the preoptic anterior hypothalamus (POAH) brain slices of cold acclimatized and room-temperature housed rats (CR and RR) and the effects of NE on the neuronal discharges were observed. The neurons of POAH in CR became much more sensitive to NE than that in RR (the threshold concentration of NE of CR became significantly lowered). In comparison with RR, the percentage of warm sensitive neurons that could be excited by NE was decreased and some of them even showed inhibitory responses. On the other hand, the percentage of cold sensitive neurons that could be inhibited by NE was decreased and some of them even showed excitatory responses. The percentage of thermo-insensitive neurons that could be either excited or inhibited by NE were increased.

[Adaptive changes of preoptic thermosensitive neurons in hypothalamic tissue slices of rats after long-term exposure to cold environmental temperature]

In the present work, thermosensitivity and spontaneous firing rate of 86 preoptic neurons in hypothalamic tissue slices from 20 cold acclimated rats (CR, at 5 +/- 1 degrees C for more than 3 weeks) and 127 neurons from 35 warm acclimated rats (WR, at 20 +/- 3 degrees C for the same period) were recorded and compared. The results showed that: (1) The percentage of cold-sensitive neurons in CR were higher than that in WR, the critical temperature and the lowest temperature of the spontaneous firing activity of cold-sensitive neurons in CR were also lower than that in WR. (2) Thermosensitivity and critical temperature of the warm-sensitive neurons in CR were remarkably decreased, and spontaneous firing rate under 37 degrees C was increased. (3) Spontaneous firing rate (37 degrees C) of temperature insensitive neurons in CR were conspicuously increased and the lowest temperature extended downward. These profound changes in response to long-term cold exposure suggested that plasticity of preoptic neurons was involved in the thermoregulation in cold adaptation.

Spontaneous rectus sheath hematoma during treatment of pulmonary embolism with warfarin: report of a case

We present a case of a patient suffering from acute abdomen with a palpable mass on the left lower quadrant of the abdominal wall. The clinical manifestations and plain abdomen gave the misleading diagnosis of a ventral hernia. A review of the patient history revealed the use of anticoagulants for pulmonary embolism, and as a result computed tomography (CT) was performed which provided an accurate diagnosis of rectus sheath hematoma. The probable pathogenesis is discussed.

Cloning of a cDNA encoding the small subunit of cytochrome b558 (cybS) of mitochondrial fumarate reductase (complex II) from adult Ascaris suum

Complex II in the mitochondria of the adult parasitic nematode, Ascaris suum, exhibits high fumarate reductase activity in addition to succinate dehydrogenase activity and plays a key role in the anaerobic energy metabolism of the worm. In this study, the amino acid sequence of the small subunit of cytochrome b558 (cybS) in adult complex II was deduced from the cDNA isolated by immunoscreening an A. suum muscle cDNA library. Histidine residues, which are possible heme axial ligands in cytochrome b558, were found in the second transmembrane segment of the subunit. This is the first report of the primary structure of the small subunit in the two-subunit cytochrome b in mitochondrial complex II from a multicellular eukaryote.

Specificity of polyunsaturated fatty acid release from rat brain synaptosomes

Release of specific polyunsaturated fatty acids for cell membranes may have a significant implication in biological function, considering the involvement of various fatty acids in cell signal transduction. In the present study, release of polyunsaturated fatty acids from rat brain synaptosomes by endogenous synaptosomal lipase activity was examined in comparison to that by cobra venom phospholipase A2 (Naja naja naja). Cobra venom phospholipase A2 (Naja naja naja) preferentially hydrolyzed docosahexaenoic acid (22:6n-3) from both synaptosomes and lipid mixtures containing similar classes of lipids commonly found in the brain. Arachidonic acid (20:4n-6) and oleic acid (18:1n-9) were also hydrolyzed; however, monoene species was hydrolyzed slower than were polyenoic species in synaptosomes. Phosphatidylethanolamine was the most preferred phospholipid class for release of 22:6n-3 fatty acid from both lipid mixtures and synaptosomes. In contrast to hydrolysis by cobra venom phospholipase A2, endogenous synaptosomal lipase activity preferentially hydrolyzed 20:4n-6 from rat brain synaptosomes, despite the high abundance of 22:6n-3 in synaptosomal membranes. Preferential release of 20:4n-6 was observed over a wide range of pH values and calcium concentrations. Synaptosomal 22:6 species appeared to be resistant to hydrolysis even after stimulation with various agents such as phorbolmyristate, suggesting that physiological importance of 22:6n-3 in neuronal membranes may not be as the release fatty acid.

Retroperitoneal lipoblastoma: report of one case

A one-year-old boy presented with progressive distension of the abdomen occurring over a few months. Computed tomography (CT) scan demonstrated a large, well-defined retroperitoneal mass with heterogeneous attenuation appearance and areas of low density showing as fatty substance. Slight enhancement of the soft tissue components was also noted. Reviewing of the literature indicates an accurate preoperative diagnosis of such fatty tumor is allowed by analysis of patient's age, tumor location, and characteristic CT pictures.

Development of the on-line high-performance liquid chromatography/thermospray mass spectrometry method for the analysis of phospholipid molecular species in rat brain

An on-line thermospray liquid chromatography/mass spectrometry method was developed to rapidly analyze phosphoglyceride molecular species in biological fluid. After total lipid extraction, the extract was subjected to the analysis using on-line reversed-phase high-performance liquid chromatography (HPLC) and filament-on thermospray mass spectrometry. Using nonconventional HPLC conditions, partial separation of individual phospholipid class (phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine, and phosphatidylcholine) and partial separation of molecular species within each class were achieved. In addition, good peak shape was maintained throughout the analysis. By monitoring characteristic fragment ions (diacylglycerol ions) formed in the filament-on thermospray process and according to the retention time, individual molecular species in each phospholipid class can be identified. Using this method, we observed significant differences in the molecular species composition of each phospholipid class in rat whole-brain lipid. Although nonlinear calibration curves were observed for all the diacylglycerol ions monitored, even in the presence of internal standard, semiquantitative and quantitative results still could be obtained for a mixture of phospholipids.

Malignant hemangioendothelioma presenting as omental masses in a child

Malignant hemangioendothelioma is an uncommon lesion of the omentum in children. Multiple foci of malignant hemangioendothelioma is even more rare in the omentum. In the present case, a computed tomography scan of the abdomen showed multiple enhanced nodular lesions. To our knowledge, this is the first report of this tumor occurring in a child.

[Angiography for the management of poorly controlled gastrointestinal hemorrhage--20 cases clinical observation]

Diagnostic and therapeutic angiography has demonstrated an important role in gastrointestinal hemorrhage. During the past 2 years, we performed angiography in the management of 20 patients with uncontrolled gastrointestinal bleeding. Conservative management including medication and transfusion would not appear to suffice in these patients and most patients had been evaluated to have a high operative risk in our series. Ten of the 20 patients had renal dysfunction (creatinine > 1.7 mg/dl) before angiography. The role of angiography in the management of patients with renal dysfunction remains controversial because angiography is likely to produce acute renal failure. We performed angiography to stop bleeding in these patients with renal dysfunction because they could die of blood loss. In our 20 cases, bleeding sites were identified in 14 patients. The detection rate was 70%. Thirteen of the 14 with the use of either vasopressin infusion or arterial embolization showed complete cessation of bleeding in 10 patients. Three cases failed to be controlled. One received an operation after a bleeding site was located by angiography. In our study, sepsis with renal failure was the leading cause of mortality (6 cases). Ten patients with pre-existing renal dysfunction had angiography performed and only one showed abrupt elevation of creatinine levels after angiography. He also developed sepsis. Deterioration of renal function was possibly due to angiography or more likely due to sepsis and hypovolemia. Six patients died of sepsis after angiography although 4 of these patients showed cessation of bleeding. Four cases with pre-existing renal dysfunction and without evidence of infection survived after angiographic management.(ABSTRACT TRUNCATED AT 250 WORDS)

Liquid chromatography/mass spectrometry of phospholipids using electrospray ionization

An improved technique for phospholipid molecular species analysis was developed using high-performance liquid chromatography/mass spectrometry with the electrospray interface. Using the 0.5% ammonium hydroxide in a water-methanol-hexane mixture and a C-18 column, complex mixtures of phospholipid molecular species were separated and detected mainly as protonated or natriated molecular species. The response was linear over 2 orders of magnitude, allowing quantification of each molecular species. In comparison to the existing LC/MS techniques, marked improvement in sensitivity was observed. The present quantification limit is approximately 0.5 pmol before split (5 fmol after 1/100 split). The relative responses were more dependent on the head group identity rather than fatty acyl composition within a phospholipid class. In general, phosphatidylcholine (PC) species are most sensitively detected followed by phosphatidylethanolamine (PE) species. The sensitivity of phosphatidylserine (PS) in the positive ion mode is approximately 20 times less in comparison to PC under our condition.

Use of computed tomography to detect hepatic portal venous gas and intestinal intramural gas: a case report

Hepatic portal venous gas and intestinal intramural gas were demonstrated by computed tomography (CT) in a case of ischemic bowel disease. The patient died on the day following the examination.

Non-surgical retrieval of intravascular foreign body: experience of 12 cases

An intravascular foreign body is an iatrogenic complication that occurs during arterial or venous catheterization or interventional procedures. The foreign body could either be a catheter fragment, a dislodged coil, or a steel guide wire. From January 1987 to December 1992, 12 cases of intravascular foreign-body removals were performed by a percutaneous method at Mackay Memorial Hospital. Of the 12 cases, five were dislodged steel guide wires, four were broken CVP catheters, two were dislodged coils, and one was Port-A fragment. The techniques we used were the loop-snare technique (two cases) and stone basket retriever (10 cases). Eleven cases of intravascular foreign bodies were removed by non-surgical percutaneous retrieval but one case was a failure due to improper extraction of a dislodged steel guide wire. The patient received surgical extraction by regional venotomy finally. No major complications were noted during or after these procedures.

Small cell carcinoma of the stomach. Case report

Small cell carcinoma of the stomach is a rare neoplasm. We report the barium meal and computed tomography findings of a 70-year-old man who presented with a long history of postprandial abdominal pain.

Characterization of cDNA clones for the 2-methyl branched-chain enoyl-CoA reductase. An enzyme involved in branched-chain fatty acid synthesis in anaerobic mitochondria of the parasitic nematode Ascaris suum

The 2-methyl branched-chain enoyl-CoA reductase plays a pivotal role in the reversal of beta-oxidation operating in anaerobic mitochondria of the parasitic nematode Ascaris suum. An affinity-purified polyclonal anti-serum against the reductase was used to screen a cDNA library constructed in lambda gt11 with poly(A)+ RNA from adult A. suum muscle. A 1.2-kilobase partial cDNA clone was isolated, subcloned, and sequenced in both directions. Additional sequence at the 5' end of the mRNA was determined by the RACE (rapid amplification of cDNA ends) procedure. Nucleotide sequence analysis of the cDNAs revealed the 22-nucleotide trans-spliced leader sequence characteristic of many nematode mRNAs, an open reading frame of 1236 nucleotides and a 3'-untranslated sequence of 109 nucleotides including a short poly(A) tail 14 nucleotides from a polyadenylation signal (AATAAA). The open reading frame encoded a 396-amino acid sequence (M(r) 43,046) including a 16-amino acid leader peptide. Two-dimensional gel electrophoresis of the purified reductase yielded multiple spots with two distinct but overlapping amino-terminal amino acid sequences. Both sequences overlapped with the sequence predicted from the mRNA, and one of the sequences was identical to the predicted sequence. Comparison of the ascarid sequence with that of mammalian acyl-CoA dehydrogenases revealed a high degree of sequence identity, suggesting that these enzymes may have evolved from a common ancestral gene even though the ascarid enzyme functions as a reductase, not as a dehydrogenase. Immunoblotting of A. suum larval stages and adult tissues with antisera that cross-reacted with each of the spots separated on two-dimensional gels suggested that the reductase was only found in adult muscle. Northern blotting using the partial cDNA revealed a hybridization band of about 1.5 kilobases and also suggested that the enzyme was tissue-specific and developmentally regulated in agreement with the results of the immunoblotting.

Purification and characterization of electron-transfer flavoprotein: rhodoquinone oxidoreductase from anaerobic mitochondria of the adult parasitic nematode, Ascaris suum

Electron-transfer flavoprotein:rhodoquinone oxidoreductase (ETF-RO) was purified to homogeneity from anaerobic mitochondria of the parasitic nematode, Ascaris suum. The enzyme has a subunit molecular mass of 64.5 kDa and is similar in many respects to the electron-transfer flavoprotein:ubiquinone oxidoreductase (ETF-UO) characterized in mammalian tissues. EPR spectroscopy of the purified enzyme revealed signals at g = 2.076, 1,936, and 1.883, arising from an iron-sulfur center, as well as signals attributable to a flavin semiquinone. Potentiometric titration on the enzyme with dithionite yielded an oxidation-reduction midpoint potential (Em) for the iron-sulfur center of +25 mV at pH 7.4. The reduction of flavin occurred in two distinct steps, with a flavin semiquinone radical detected as an intermediate. The Em values for the two steps in the complete reduction of flavin were +15 mV and -9 mV, respectively. Physiologically, the ascarid ETF-RO accepts electrons from a low potential quinone, rhodoquinone, and functions in a direction opposite to that of the ETF-UO. Incubations of A. suum submitochondrial particles with NADH, 2-methylcrotonyl-CoA, purified A. suum electron-transfer flavoprotein and 2-methyl branched-chain enoyl-CoA reductase resulted in significant 2-methylbutyryl-CoA formation, which was inhibited by both rotenone and antisera to the purified ETF-RO. Quinone extraction of the submitchondrial particles with dry pentane resulted in almost the complete loss of 2-MBCoA formation by the system. However, the reincorporation of rhodoquinone, but not ubiquinone restored over 50% of the NADH-dependent 2-MBCoA formation.

Declining blood lead levels and cognitive changes in moderately lead-poisoned children

OBJECTIVE

To determine whether chelation therapy or biochemical changes during a lead-lowering intervention was associated with changes in cognitive functioning of moderately lead-poisoned children. It was hypothesized that cognitive performance would improve as blood lead level declined over time.

DESIGN

Short-term intervention study with measures obtained before and after intervention.

SETTING

Hospital specialty clinic and university research center.

PATIENTS

A total of 154 previously untreated children referred to clinic with blood lead levels between 1.21 and 2.66 mumol/L (25 and 55 micrograms/dL) at time of enrollment. Ages ranged from 13 to 87 months.

INTERVENTION

Enrolled children were treated with edetate calcium disodium (EDTA) if eligible and/or with orally administered iron supplement if iron deficient. For all children, housing inspections and abatement procedures were performed as necessary.

MAIN OUTCOME MEASURES

Score on Bayley Mental Development Scale or Stanford-Binet Intelligence Scale (4th edition).

RESULTS

There was no effect of edetate calcium disodium treatment per se. In the short term (7 weeks), changes in blood lead levels were not related to changes in cognitive scores. In the long term (6 months), however, changes in performance were significantly related to changes in blood lead level, even after controlling for confounding variables. The standardized score increased 1 point for every decrease of 0.14 mumol/L (3 micrograms/dL) in blood lead level.

CONCLUSION

The results suggest an association between decreases in blood lead level and cognitive improvements in moderately lead-poisoned children.

Electron-transfer complexes of Ascaris suum muscle mitochondria. III. Composition and fumarate reductase activity of complex II

Complex II of the anaerobic respiratory chain in Ascaris muscle mitochondria showed a high fumarate reductase activity when reduced methyl viologen was used as the electron donor. The maximum activity was 49 mumol/min per mg protein, which is much higher than that of the mammalian counterpart. The mitochondria of Ascaris-fertilized eggs, which require oxygen for its development, also showed fumarate reductase activity with a specific activity intermediate between those of adult Ascaris and mammals. Antibody against the Ascaris flavoprotein subunit reacted with the mammalian counterparts, whereas those against the Ascaris iron-sulfur protein subunit did not crossreact, although the amino acid compositions of the subunits in Ascaris and bovine heart were quite similar. Cytochrome b-558 of Ascaris complex II was separated from flavoprotein and iron-sulphur protein subunits by high performance liquid chromatography with a gel permeation system in the presence of Sarkosyl. Isolated cytochrome b-558 is composed of two hydrophobic polypeptides with molecular masses of 17.2 and 12.5 kDa determined by gradient gel, which correspond to the two small subunits of complex II. Amino acid compositions of these small subunits showed little similarity with those of cytochrome b-560 of bovine heart complex II. NADH-fumarate reductase, which is the final enzyme complex in the anaerobic respiratory chain in Ascaris, was reconstituted with bovine heart complex I, Ascaris complex II and phospholipids. The maximum activity was 430 nmol/min per mg protein of complex II. Rhodoquinone was essential for this reconstitution, whereas ubiquinone showed no effect. The results clearly indicate the unique role of Ascaris complex II as fumarate reductase and the indispensability of rhodoquinone as the low-potential electron carrier in the NADH-fumarate reductase system.