Stanniocalcin 2: characterization of the protein and its localization to human pancreatic alpha cells

Stanniocalcin (STC) is a hormone that was originally identified in fish, where it inhibits calcium uptake by the gills and gut and stimulates phosphate adsorption by the kidney. Recently, two mammalian homologues of stanniocalcin were identified. The first (STC1) shows 61% identity to the fish stanniocalcins and appears to have a function similar to that of the fish stanniocalcins. The second homologue (STC2) is 30-38% identical to the fish stanniocalcins, and is characterized by unique cysteine and histidine motifs that are not found in the other stanniocalcins. We purified both the native hamster and recombinant human STC2 proteins and obtained a partial amino acid sequence of the hamster protein. Both proteins behave as a disulfide bonded homodimer, which undergoes post-translational modification(s). The STC2 gene was localized to human chromosome 5q35. Northern blot analysis revealed that the primary site of human STC2 production is the pancreas, and immunostaining localized the STC2 protein to a subpopulation of cells in the islet. Double immunostaining for STC2 and either insulin or glucagon revealed that STC2 protein is found in the alpha cells, but not the beta cells. We speculate that STC2 may play a role in glucose homeostasis.

Thoracoscopic procedure for intrathoracic diseases: current status in mainland China

One hundred and five patients underwent a procedure of video-assisted thoracoscopic surgery (VATS) during a period of 5 years, in the Department of Cardiothoracic Surgery, Peking Union Medical College Hospital, Beijing, China. Among them, there were 36 cases suffering from spontaneous pneumothorax, 24 having a nodule of the lung, nine intrathoracic multiple nodules, 10 undefined pleural effusions, eight mediastinal mass, 15 interstitial fibrosis, two pericardial effusion, and one severe emphysema. In all patients of this series, the diagnosis was demonstrated and the suitable management was performed.

[Expression of HBsAg by using various eukaryotic expression vectors]

OBJECTIVE

To establish efficient eukaryotic expression system of HBsAg and its variants.

METHODS

A series of expression vectors were constructed by cloning HBV S gene and its mutant genes from recombinant vector pBluescript pBKS(+)-HBs containing S gene and its mutant genes into eukaryotic expression vectors: pMEP4, pCEP4, pLXSN, PXT1, pcDNA3. These recombinant eukaryotic expression vectors were transfected into human hepatocellular carcinoma cells (HepG2).

RESULTS

The cell lines expressing recombinant proteins were stably established.

CONCLUSION

All expression vectors could express HBsAg and its variants, but their transfecting efficiency, expressing efficiency and stability of expression were different. The establishment of highly efficient expression system in this study paves the way for further study on biologic characters of HBsAg variants, genetic immunization and genetic therapy.

Enzyme-linked immunoelectrotransfer blotting analysis of human serologic responses to infective hookworm larval antigen

OBJECTIVE

To explore the possibility of using specific antigens for immunodiagnosis of hookworm disease in endemic area.

METHOD

Infective third-stage larvae of the canine hookworm, Ancylostoma caninum (A. caninum), were prepared as the source of antigen. Enzyme-linked immunoelectrotransfer blotting (EITB) was employed as an immunodiagnostic method.

RESULTS

Two immunodominant bands of hookworm antigens (42 kDa and 55 kDa) were recognized by the sera of hookworm-infected patients (serum dilution 1:200; antigen centrifuged at 36,000 r/m for 20 minutes, but not by sera from negative controls.

CONCLUSION

The 42 kDa and 55 kDa A. caninum antigens might be the specific antigens that could be used for immunodiagnosis of hookworm disease in endemic area.

[Humoral and cell mediated immunity induced by HBV-S gene recombinant retroviral vector]

OBJECTIVE

To investigate the effectiveness of recombined retrovirus vector in gene therapy.

METHODS

The retroviral vector PLXSN-S was constructed and transferred into PA317 by means of electroporation, then HepG2, P815, and EL4 cells were infected with the pseudovirus produced from PA317. In the meantime the gene immunization of PLXSN-S was also studied.

RESULTS

HBsAg was expressed variously in the eukaryotic cells mentioned above and successfully evoked antibody response and CTL response to HBsAg after gene immunization.

CONCLUSION

Intramuscular DNA immunization represents an efficient technique for priming CTL and antibody response to HBsAg. PLXSN may be used as an effective vector to carry genes of interest to target cells and immunization with it's DNA vaccine might be clinically useful for gene therapy.

[Management of thoracic esophageal perforation]

OBJECTIVE

To compare surgical management of esophageal perforation on thoracic portion with nonoperative management.

METHODS

Seventeen patients were treated for thoracic esophageal perforation at our department between 1962 and 1996. Among them, seven patients underwent nonoperative management. The remaining 10 had operative procedures (primary repair in 5, esophagostomy in 3, and drainage alone in 2 cases).

RESULTS

Postoperative leakage occurred in 2 patients; among the two leakages, 1 required cervical esophagostomy, and 1 became a controlled fistula needed pleural drainage and feeding jejunostomy. One patient had anastomotic narrowing after esophagostomy. Of patients with nonoperative management, five survived (with 28% in-hospital mortality rate), Whereas only one patient, who was treated by surgical procedure, died (with 10% inhospital mortality rate). The mean hospital stay in nonoperative and operative group were (28.3 +/- 12.9) days and (57.6 +/- 52.7) days respectively.

CONCLUSIONS

The clinical observation suggested that rapid diagnosis of thoracic esophageal perforations is essential and once the diagnosis of esophageal perforation is established, a appropriate management must be selected promptly.

[Expression of recombinant inserting mutants of HBsAg in vitro and its antigenic analysis]

OBJECTIVE

To study the immunological characteristics of two inserting variants of HBsAg as further to elucidate the role of inserting mutants in the development of HBsAg-negative chronic hepatitis B.

METHODS

The inserting mutants of HBsAg were constructed by PCR-mediated mutagenesis in vitro. Epstein-Barr virus vector pCEP4 and retrovirus vector PXT1 carrying the mutant genes of HBsAg were transfected into mammalian cells. The affinity of polyclonal and monoclonal antibodies against HBsAg for mutant antigens were studied by ELISA and western blot.

RESULTS

Two insertions were introduced into s gene, and a six nucleotide insertion introduced two aminoacids (Arg and Ala) between codons 122 and 123 of the s polypeptide, whereas a nine nucleotide insertion introduced three aminoacids(Arg, Gly and Ala) between codons 123 and 124. These s genes were subcloned into two eukaryotic expression vectors (pCEP4 and PXT1), and the recombinant eukaryotic expression plasmids had been constructed, which could express s polypeptide in mammalian cells. Cell lines expressing wild-type or mutant-type HBsAg stably were obtained after transfection of these vectors into mammalian cells. Two two inserting variants failed to react with polyclonal and monoclonal antibodies against HBsAg by ELISA and Western blot.

CONCLUSION

The insertions may result in a conformational change of the s protein, and affect its antigenicities, suggesting that the inserting mutations may be critical for immunoescape of HBV and in part responsible for chronicity of HBsAg-negative patients.

Dexamethasone stimulates human A1 adenosine receptor (A1AR) gene expression through multiple regulatory sites in promoter B

The expression of the human A1 adenosine receptor gene is controlled by two promoters, promoters A and B, and they are located 600 base pairs apart. The characteristics of the two promoters differ by the activity of expression, tissue specificity, and the potential regulatory elements around them. Promoter A is more active but its expression is observed only in selected tissues, whereas promoter B is constitutively expressed but at much reduced levels. In Chinese hamster ovary (CHO) cells transiently transfected with plasmids containing either promoter linked to a reporter gene, dexamethasone (dex) can stimulate (or enhance) the expression of promoter B much more effectively than that of promoter A. Mutation and deletion studies on plasmids containing promoter B have shown that the stimulation is mediated through multiple regulatory sites, including a serum response element, AP1, and TATA box. However, a single-glucocorticoid response element monomer-binding site between promoters A and B does not have significant contribution to dex-regulated expression. The interactions between glucocorticoid receptor (GR) and some regulatory sites are probably occurring via this protein (GR) interacting with other DNA-binding proteins because there is no GR DNA-binding sequence in the sites studied. The stimulation can be eliminated by mifepristone, an antagonist of GR, indicating the involvement of GR in gene regulation. In addition, dex treatment also stimulated the expression of A1 adenosine receptors in CHO cells transfected with the plasmids containing contiguous genomic sequences of promoter B or promoters A and B linked to the receptor-coding sequence. When promoter A is active and both promoter A and B are present in a construct, dex treatment induced a much smaller percentage of stimulation.

[Open lung biopsy in diagnosis of interstitial lung disease]

OBJECTIVE

To evaluate the role of open lung biopsy in diagnosis of interstitial lung disease.

METHODS

24 patients with interstitial lung disease who underwent open lung biopsy from 1993 to June 1998 were reviewed.

RESULTS

The documented pathologic diagnosis in 24 patients with interstitial lung disease who underwent open lung biopsies were: 7 IPF (UIP), 1 acute interstitial pneumonia (AIP), 3 BOOP, 2 DPB, 3 sarcoidosis, 2 tuberculosis, 1 histiocytosis-X and 1 lung cancer. Most of these patients did not definitely diagnosed through their clinical evaluation including history, chest X-ray, pulmonary function tests and TBLB.

CONCLUSIONS

Open lung biopsy, is a useful method, as it is sensitive and specific in diagnosis of interstitial lung disease. It is helpful in defining the site and extent of interstitial lung disease and diagnosing rare and atypical interstitial lung disease.

Role of Helicobacter pylori infection in pathogenesis of gastric adenocarcinoma

To study the effect of Helicobacter Pylori (Hp) on the process of gastric carcinogenesis, 35 cases of chronic gastritis, 20 cases of gastric adenocarcinoma were studied by use of transmission electron microscopy, immunohistochemical and molecular biological technique. The results showed that 24 of 35 cases of chronic gastritis were positive for Hp, 11/20 cases of gastric adenocarcinoma were Hp positive. PCNA positive cell labeling index (LI) in Hp-associated chronic gastritis (LI = 20.6 +/- 4.7) was higher than that in Hp negative chronic gastritis (LI = 11.3 +/- 5.2) (P < 0.05). HSP70 expression of gastric adenocarcinoma tissues in Hp-infected patients were lower than that of non-Hp-infected gastric cancer. p53 gene mutation was found in gastric adenocarcinoma with positive Hp. It was suggested that Hp may enhance gastric cell proliferation, decrease the expression of HSP70 which induces p53 mutation.

A clinicopathological study of Alport syndrome and detection of type IV collagen chains in Alport patients

OBJECTIVE

To summarize the clinical and pathological findings of Alport syndrome (AS), detect the distribution of type IV collagen within basement membrane of patients with AS and evaluate the diagnostic value of indirect immunofluorescence (iIF) study of type IV collagen in AS.

METHODS

Fourteen patients belonging to 12 families were collected from January 1990 to June 1996. The clinical examinations include biochemical examination, audiometry and ocular examination. IIF technique was used to detect the location of chains of type IV collagen in 6 renal and 5 skin specimens from 8 Alport patients.

RESULTS

Among fourteen patients, 11 were male and 3 female (mean age 29.4 years). Microscopic hematuria was found in 13 patients, and recurrent gross hematuria in 7. All had proteinuria. Three patients presented nephrotic syndrome. Slowly progressive renal failure occurred in 10 of 11 males (11-39 years) and 1 female (40 years). Sensorineural deafness was observed in 9 patients particularly high frequency sound. Anterior lenticonus were presented in 2. Five families transmitted as X-linked dominant (XD) trait and 3 autosomal dominant, 3 autosomal recessive inheritance. In 7 renal biopsies, the findings by light microscopy mostly revealed focal and segmental sclerosis glomerulonephritis (4/7). The results of IF were negative in 4. Ultrastructural studies showed variable thickening, thinning of glomerular basement membrane (GBM) in 7 specimens with lamellation and basket wearing of GBM in 1. Using the iIF technique, the alpha 3, 4, 5 (IV) chains were observed to be absent within both GBM and EBM of 4 male XD-AS patients. Six patients were treated with hemodialysis, 2/6 with transplantation.

CONCLUSION

Alport syndrome (AS) is a heterogeneous hereditary disease characterized by progressive hematuric nephritis with or without sensorineural hearing loss and ocular defects. Ultrastructural alterations of GBM are helpful to the diagnosis of AS. IIF study suggests that type IV collagen in basement membrane of AS was abnormal and iIF study of type IV collagen chains distribution is useful for confirming the diagnosis of AS.

Herbimycin A enhances apoptotic effect of chemotherapeutic drugs on K562 cells

OBJECTIVES

To explore the anti-apoptotic mechanism and the effective apoptosis-inducing method in chronic myelogenous leukemia (CML) cells.

METHODS

K562 cell line was used to observe the effect of combination of herbimycin A (HMA), a tyrosine kinase inhibitor, and chemotherapeutic agents on the induction of apoptosis.

RESULTS

HMA or chemotherapeutic agents could inhibit the proliferation but not significantly induce apoptosis of K562 cells. However, HMA significantly enhanced apoptosis when combined with chemotherapeutic agents. Addition of sulfhydryl compound to the cultures to conjugate HMA completely abrogated this enhancing effect on K562 cells.

CONCLUSIONS

HMA increases the sensitivity of CML cells to chemotherapeutic agents by inactivating tyrosine kinase activity. It is promising that combination of HMA with conventional chemotherapeutic drugs may be a new strategy in the treatment of CML.

[Diagnosis and treatment of thoracic outlet syndrome]

OBJECTIVE

Thoracic outlet syndrome (TOS) is clinically common, but liable to be misdiagnosed. We would like to emphasize the recognition of TOS, and through thorough examination for a complete relief from indicated operation.

METHODS

13 cases receiving surgical operations in PUMC hospital from 1982 to 1996 are reported and discussed the cause of misdiagnosis, investigate the various kinds of abnormalities and compare the result of operation.

RESULTS

92% of the patients had experence of being misdiagnosed for other diseases, the history may be as long as 10 years. In the operations we found 8 kinds of anatomic abnormalities that cause the symptoms and complete relief is satisfactory.

CONCLUSIONS

We have to emphasize the recognition of TOS. The thorough physical examination is important to diagnosis. Patients with typical and apparent symptoms need an operation to relieve the thoracic outlet through the transaxillary approach.

Recent developments in DNA electrophoretic separations

DNA electrophoresis is now a fairly mature technology. Nevertheless, as we approach the 21st century, new ideas are frequently suggested that could lead to a revolution for DNA sequencing and mapping. Here, we review some of the novel concepts that have been studied since ca. 1990. Our review focuses on new separation mechanisms, new sieving matrices and recent conceptual advances.

[Subxiphoid pericardial window drainage in the management of large pericardial effusions]

OBJECTIVE

To choose a safe, effective, minimum invasive procedure for treatment of patients with a large pericardial effusion and cardiac tamponade.

METHODS

Retrospective analysis of 30 cases with large pericardial effusion or cardiac tamponade diagnosed by echocardiography during four years (1993-1997). The subxiphoid pericardial window drainage and pericardial tissue biopsy was performed.

RESULTS

The symptoms were improved immediately following the drainage. The drainage volume during operation was 200-2,000 ml, and postoperation was 0-2,000 ml. The drainage tube was kept in position for average of 5.6 days. With the echocardiography follow up, the pericardial effusion disappeared or remained only minimum fluid in 96.7% of the patients. The complications happened in 6 cases. The 30-days mortality was 6.7%.

CONCLUSIONS

The subxiphoid pericardial window drainage procedure is the first choice for a safe, effective, minimal invasive and easy to do procedure for the patients with a large pericardial effusions or cardiac tamponade.

Cutaneous and subcutaneous granulomata formation in mice immunized and challenged with third-stage infective hookworm (Ancylostoma caninum) larvae

To determine the inflammatory and immunological mechanisms associated with live third-stage (L3) hookworm larval vaccines, mice were immunized either subcutaneously or orally with three doses of 500 L3 of Ancylostoma caninum at 2-week intervals, and then challenged percutaneously (via abdominal skin) with 500 L3. Non-immunized mice served as negative controls. Skin was excised from post-challenge mice at intervals between 6 h and 28 days, and then examined by light microscopy. In non-immunized mice the L3 exhibited no structural damage and infiltrating inflammatory cells were absent from the surrounding tissues. There were no changes in the cutaneous architecture. In contrast, skin recovered from the immunized mice was edematous and exhibited marked inflammatory changes with resultant destruction of the challenge L3. At 6 h post-challenge the L3 exhibited cuticular swelling and damage; the surrounding tissue was infiltrated by polymorphonuclear inflammatory cells. By 24 h granulomata in the dermis, subcutaneous tissues and underlying abdominal muscles were first observed surrounding dead L3. The number of granulomata peaked at 72 h, with the majority distributed in the subcutaneous tissues. Plasma cells predominated in the early granulomata, but by 3-7 days post-challenge foreign body giant cells began to appear. In some cases, intact and presumably living L3 were noted in the abdominal muscles 14-28 days post-challenge, which suggested that protection against larval challenge was not absolute. Granuloma formation appears to be a major component of the post-vaccination murine host immune response against challenge larvae. The observation generates several hypotheses to investigate the mechanisms of protection afforded by living helminth vaccines.

Oxidative stress increases A1 adenosine receptor expression by activating nuclear factor kappa B

The A1 adenosine receptor (A1AR) contributes to the cytoprotective action of adenosine under conditions known to generate reactive oxygen species (ROS). Pharmacological manipulation of A1AR expression has been shown to modulate this cytoprotective role. In this study, we provide evidence that ROS generated could increase the expression of the A1AR and thereby offset the detrimental effects of ROS. Incubation of DDT1MF-2 smooth muscle cells with ROS-generating chemotherapeutic agents, such as cisplatin (2.5 microM) or H2O2 (10 microM), elicited an increase in A1AR expression within 24 hr. The induction by H2O2 was reduced by the ROS scavenger catalase but not superoxide dismutase. Inhibition of nuclear factor kappa B (NF kappa B) by pyrrolidine dithiocarbamate (200 microM), dexamethasone (100 nM), or genistein (1 microM) abrogated the cisplatin-mediated increase in A1AR. Cisplatin promoted rapid translocation of NF kappa B (but not AP-1) to the nucleus, as detected by electrophoretic mobility shift assays and by Western blotting. A putative NF kappa B sequence in the A1AR promoter effectively competed with labeled kappa B probe for binding in nuclear preparations derived from DDT1MF-2 cells. Transient transfection of DDT1MF-2 cells with the A1AR promoter coupled to firefly luciferase reporter gene led to cisplatin-inducible and pyrrolidine dithiocarbamate-sensitive luciferase activity, suggesting the presence of functional NF kappa B binding site(s) in the A1AR promoter sequence. Treatment of cells with (R)-phenylisopropyladenosine (1 microM), an agonist of the A1AR, reduced cisplatin-mediated lipid peroxidation, which was reversed after blockade of the A1AR. These data suggest that ROS can increase the expression of the A1AR by activating NF kappa B regulatory site(s) on this gene and thereby enhance the cytoprotective role of adenosine.

[Polymerase chain reaction associated with dig-labelled DNA hybridization of mip gene to identify new isolated Legionella pneumophila strains]

OBJECTIVE

By testing mip gene, one highly conservative virulence gene of Legionella pneumophila (Lp), as targets of polymerase chain reaction (PCR) and Digoxin-labelled probe hybridization to establish a rapid, specific and sensitive gene analysis method that can identify new isolated suspected bacteria strains as Lp.

METHOD

Abstracting all the CDC reference Lp strains' and none-Lp Legionella strains' DNA, as well as the domestic isolated Lp strains' and some non-Legionella control bacteria's DNA as templates, then were processed. All the positive PCR products(if no PCR amplicons were available, the original whole DNA should be detected) were hybridized with Digoxingen-labelled mip gene probe in dot-blot procedure.

RESULT

All the tested Lp strains had positive PCR and hybridization results, at the same time, all none-Legionella bacteria and none-Lp Legionella strains got negative results. 6 of 26 isolates were identified as Lp strains by this method.

CONCLUSION

Such a Lp strain identification procedure shows high specificity and sensitivity (nearly 100%, in this study), and mean-while can be completed in a relative short time. Surely, this method can be largely available and has a potential value in diagnosis of clinical Legionellosis cases and pursuing the pathogen during Legionnaires' disease outbreaks.

Adenosine A1 receptor and bipolar affective disorder: systematic screening of the gene and association studies

In the present study we sought to identify genetic variation in the adenosine A1 receptor (A1AR) gene on chromosome 1q31-32.1, which through alteration of protein function or level of expression might contribute to the genetic predisposition to bipolar affective disorder. We performed a systematic mutation scan of the whole coding sequence as well as 5' and 3' untranslated regions by means of single-strand conformation analysis. The region upstream to the coding sequence we investigated contains two functional promoters. Screening 42 patients with bipolar affective disorder, we detected 11 DNA sequence variants (48T/A, 267 + 275C/T, 805T/G, 1777C/A, 1827C/T, 1904C/T, 2126G/T, 2294insT, 2776C/T, 2777del36, 2819T/G). Determining the frequency of these variants in 42 anonymous blood donors, we observed a non-significant (P < 0.06) trend towards an underrepresentation of the 2126T variant in patients when compared to controls. On the other hand, the 2777del36 and the 2819G variant were not found among the controls. These findings were followed up in a large independent replication sample. However, we were not able to confirm the initial findings in the second sample. Our data suggest that genetically determined variation of the A1AR and its two promoters do not play a major role in the development of bipolar affective disorder.

[Simultaneously monitoring end tidal CO2 and other parameters versus anesthesia management]

OBJECTIVE

To investigate the significance of end tidal CO2(ETCO2) combined with other techniques in anesthesia management.

METHODS

Twenty two patients undergoing general anesthesia were monitored with electromyocardiogram (ECG), invasive arterial blood pressure (IABP), plethysmogram and capnography simultaneously. Ten patients undergoing epidural anesthesia and cervical plexus block were monitored with ETCO2.

RESULTS

During general anesthesia the depth of general anesthesia, status of ventilation and the degree of muscle relaxation could be grossly evaluated by simultaneously monitoring ETCO2, capnography, plethysmogram, ECG and IABP. ETCO2 could also provide an objective standard for the assessment of respiratory function during spontaneous ventilation.

CONCLUSIONS

ETCO2 combined with other monitoring techniques can increase the safety of anesthesia and the accuracy of anesthesia management.

[Renal aquaporin-2 water channel expression in congestive heart failure rat]

OBJECTIVE

To study aquaporin-2 (AQP2) that mediates vasopressin-regulated collecting duct water permeability.

METHODS

Male Sprague-Dawley rats (200-250 g) underwent either a left coronary artery ligation, a model of CHF, or a shamoperation (Sham-Op). Five weeks after surgery, mean blood pressure (MBP) and cardiac output (CO) were measured by catheterization in the conscious animal. The rats were sacrificed 24 hours later. Left ventricular myocardial infarction size (LVMI) was estimated and the rats were divided into two groups according to the size of infarction. Total RNA and protein were extracted from whole kidney. AQP2 and GAPDH mRNA were measured by Northern blot and AQP2 protein expression by Western blot.

RESULTS

AQP2/GAPDH mRNA densities of Sham-Op, LVMI < 20% rats and LVMI > or = 20% rats were 1.385 +/- 0.023, 1.523 +/- 0.036, and 1.779 +/- 0.072 (P < 0.01). AQP2 protein Western blot densities were 100% +/- 10%, 157% +/- 13% and 202% +/- 25% (P < 0.01).

CONCLUSION

Both mRNA and protein of AQP2 gene expression are increased in CHF rat and this upregulation is present in the compensated (LVMI < 20% rats) and decompensated (LVMI > or = 20% rats) stage of CHF. This contributes to water retention associated with CHF.

A single-stranded DNA binding site in the human A1 adenosine receptor gene promoter

Human A1 adenosine receptor gene expression is controlled by two independent promoters. The upstream promoter, promoter A, is subject to tissue specific regulation because not all cells express the mRNA associated with this promoter. One potential regulatory sequence located downstream of the TATA box is an AGG element appearing in a tandem repeat. In a previous study, transient transfection assays showed that mutations made in those AGG elements substantially reduced promoter activity. In the current study, DNase I footprinting indicated nuclear protein binding to this sequence between the TATA box and transcriptional start site. Electrophoretic mobility shift assay confirmed further the presence of an AGG element binding protein (AGBP) in human brain nuclear protein extracts. This binding protein has much higher affinity for single-stranded than for double-stranded DNA, and the binding is sequence specific. A series of assays also showed that AGBP is not related to the nuclear factor SP1 and the binding does not require metal cofactors. Therefore, AGBP is likely to be a specific single-stranded DNA binding protein that is required for the full expression of A1 adenosine receptor gene and particularly abundant in brain tissue.