The effects of transcription and RNA processing on the initiation of chloroplast DNA replication in Chlamydomonas reinhardtii

In Chlamydomonas reinhardtii, the origin for chloroplast DNA replication, Ori A, overlaps the coding region for the chloroplast ribosomal protein Rpl16. In an in vitro DNA replication system that uses cloned Ori A as template, alteration of transcription across rpl16 affects replication activity. S1 nuclease protection mapping of cellular RNA derived from this region revealed multiple 5' and 3' ends, and several 3' ends were mapped within mini Ori A (224 bp), the core region for replication initiation. We also demonstrated that the protein fraction used in the in vitro DNA replication system contained an RNA processing activity responsible for the generation of multiple 3' ends. The 3' ends of some of the processed RNA species coincided with those of the cellular transcripts. Initiation of DNA replication in the in vitro system changed the abundance of some of the processed RNA species, and the S1 nuclease protection pattern generated by the 3' ends now mimicked that of the in vivo transcripts. We also monitored the pattern of 3' ends in cellular transcripts from the rpl16 region during gametogenesis--when the chloroplast DNA is under-replicated--and detected a change in transcript abundance that correlated with that seen in the in vitro study. Measurements of the template activity of mutants with targeted sequences change near the sites of processing also supported the notion that the processed transcripts play an important role in DNA replication.

An in vitro monitoring system for simulated thermal process in cryosurgery

This paper describes a new in vitro experimental model that records temperature changes over a culture plate, which then can be used to assess the biological effects of cryosurgery. A cryoprobe and 16 thermocouples set up by a computer control system were used to monitor the temperature changes during freezing and thawing in a culture plate, and the data were used to create a temperature profile of the entire plate. Location of the thermocouples was confirmed by a digital camera viewing from under the plate, and temperature changes at any point in the interpolated areas were estimated using a curve fitting method. The estimated temperature was checked by sampling with four additional randomly placed thermocouples. Linear regression analysis showed that the estimated temperature and measured temperature were very close (correlation coefficients 0.98-0.99). MBT-2 tumor cells were cultured and then subjected to simulated cryosurgery. The surviving cells were stained with crystal violet and the cell death boundary was detected by image processing. Temperature history at the cell death boundary was retrieved and analyzed. With this system it is possible to recreate the temperature changes that result in a certain biological effect (such as cell death) during the process of simulated cryosurgery.

Antibiotic treatment of orbital cellulitis: an analysis of pathogenic bacteria and bacterial susceptibility

The proper choice of effective antibiotics is a mainstay for the treatment of orbital cellulitis. The lack of native data regarding the microorganism causing the infection and its antibiotic sensitivity prompted us to conduct this study. We retrospectively collected 29 cases of orbital cellulitis admitted to Chung-Ho Memorial Hospital of Kaohsiung Medical College from January 1994 to September 1998. The effectiveness of antibiotics with bacterial susceptibility was analyzed. Of the 29 cases, fifteen were male and fourteen female. The patients ranged in age from 7 months to 79 years (mean, 37.6 years). Sinusitis (9 cases, 31.0%) is the most common etiology. Fourteen cases received both medical and surgical treatments. Eighteen cases had purulent discharge from the infection areas sent for culture isolation of the microorganism. The culture positive rate was 50% (9 in 18 cases). The Staphylococcus aureus (5 cases) was the most common pathogen. The bacterial susceptibility test showed drug resistance of 100% for penicillin G (seven out of seven cases; 7/7), 100% for ampicillin (10/10), and 0% for amikacin (0/3) and vancomycin (0/7). Penicillin and ampicillin are not effective for those isolated bacteria. Oxacillin and gentamicin, frequently used in first line treatment, might encounter drug resistance in some cases. Amikacin and vancomycin, without any resistance in bacterial susceptibility tests, could be used in vision-threatening, critical, and intractable cases.

Composite graft tear and aortico-left ventricular tunnel after aortic root replacement using Cabrol's technique

Woven graft tera is a very rare complication after aortic root replacement using Cabrol's technique. In this report, we present a 40-year-old man with aortic annular ectasia and severe aortic regurgitation who underwent four revisional aortic valve operations because of recurrent paravalvular leakage after valve repair and/or replacement. The Bentall operation with translocated aortic valve and Cabrol's coronary artery anastomosis were performed in the fifth operation, because of progressive dilatation of the aortic root and ascending aorta. Unfortunately, aortico-ventricular tunnel developed 2 years after aortic root replacement using Cabrol's technique. Graft tear and proximal anastomotic leakage were found to be the cause of the tunnel during the sixth operation. The patient died of myocardial failure 8 days after the seventh aortic root replacement operation. The devastating result of this complication should alert cardiovascular surgeons to the possibility of graft failure after the Bentall operation.

Three-dimensional ultrasound in the assessment of fetal cerebellar transverse and antero-posterior diameters

Fetal cerebellum scanning by prenatal ultrasound (US) is very important for early detection of fetal central-nervous-system anomaly, as well as for the determination of gestational age (GA). Due to the small organ size and the unique shape of the fetal cerebellum (CL), accurate measurement of the dimensions of CL by two-dimensional (2-D) US is not easy if the appropriate plane cannot be reached. With the advent of three-dimensional (3-D) US, the disadvantages of 2-D US in assessing the fetal CL dimensions can be avoided. The purpose of this study was to assess the fetal cerebellar transverse diameter (CTD) and cerebellar antero-posterior diameter (CAD) using 3-D US. First, we compared the reproducibility of 2-D and 3-D US on the assessment of fetal cerebellar dimensions. Second, we prospectively measured CTD and CAD in 223 healthy fetuses using a cross-sectional design with an attempt to establish the normal growth charts of fetal CL. Our results showed 3-D US is superior to 2-D US in the reproducibility test of fetal cerebellar dimensions. In addition, with GA as the dependent variable, polynomial regression analysis showed that the best-fit equations for both CTD vs. GA and CAD vs. GA were the first-order. The best-fit predictive equation of GA by CTD was GA (week) = 9.0281 + 0. 58533 x CTD (mm) (r = 0.95, n = 223, SE = 1.82 weeks, p < 0.0001), and the best-fit predictive equation of GA by CAD was GA (week) = 10. 855 + 1.1672 x CAD (mm) (r = 0.82, n = 223, SE = 3.41 weeks, p < 0. 0001). Furthermore, all the correlation coefficients of CTD or CAD vs. the common fetal growth indexes were also highly significant (all p < 0.0001). In conclusion, our data of fetal CL dimensions assessed by 3-D US may serve as a useful reference in assessing fetal CL growth, dating GA or detecting fetal CL anomalies.

Cloning, sequencing, heterologous expression, purification, and characterization of adenosylcobalamin-dependent D-lysine 5, 6-aminomutase from Clostridium sticklandii

D-Lysine 5,6-aminomutase from Clostridium sticklandii catalyzes the 1,2-shift of the epsilon-amino group of D-lysine and reverse migration of C5(H). The two genes encoding 5,6-aminomutase have been cloned, sequenced, and expressed in Escherchia coli. They are adjacent on the Clostridial chromosome and encode polypeptides of 57. 3 and 29.2 kilodaltons. The predicted amino acid sequence includes a conserved base-off 5'-deoxyadenosylcobalamin binding motif and a 3-cysteine cluster in the small subunit, as well as a P-loop sequence in the large subunit. Activity of the recombinant enzyme exceeds that of the 5,6-aminomutase purified from C. sticklandii by 6-fold, presumably due to the absence of bound, inactive corrinoids in the recombinant enzyme. The K(m) values for adenosylcobalamin and pyridoxal 5'-phosphate are 6.6 and 1.0 microM, respectively. ATP does not have a regulatory effect on the recombinant protein. The rapid turnover associated inactivation reported for the enzyme purified from Clostridium is also seen with the recombinant form. Aminomutase activity does not depend on structural or catalytic metal ions. Electron paramagnetic resonance experiments with [(15)N-dimethylbenz-imidazole]adenosylcobalamin demonstrate base-off binding, consistent with other B(12)-dependent enzymes that break unactivated C-H bonds.

Upregulation of L-plastin gene by testosterone in breast and prostate cancer cells: identification of three cooperative androgen receptor-binding sequences

L-Plastin is normally a leukocyte-specific actin-binding protein; it is also expressed in the majority of human cancer cell lines that are derived from many types of solid tumors. We have previously reported the isolation of the L-plastin gene promoter, in which we identified several potential steroid receptor-binding sequences. We now obtained evidence that L-plastin gene expression was positively regulated by testosterone in androgen receptor (AR)-positive prostate and breast cancer cells. DNase I footprint analysis identified three AR-binding elements (ARE) located in a 545-bp region approximately 1.1 kb upstream from the transcription initiation site. However, each of these three AREs exhibited very little testosterone/AR-responsive enhancer activities toward a test promoter (of the thymidine kinase gene) when tested in MCF-7 breast cancer cells. Their testosterone/AR responsiveness became evident only when two or three of them were combined. In PC-3 prostate cancer cells, cooperation among L-plastin AREs was still evident although individually they had moderate levels of testosterone/AR responsiveness. Thus, the three L-plastin AREs, despite their imperfect sequences compared with the consensus ARE, could cooperate with each other to become a potent testosterone/AR-responsive unit, which was likely responsible for the inducibility of the L-plastin gene by testosterone.

Relapsing pancreatitis in a child duplication in an aberrant pancreatic lobe

An aberrant pancreatic lobe associated with an enteric duplication cyst is a rare cause of relapsing pancreatitis in childhood. We present an 8-year-old boy with relapsing pancreatitis caused by this rare congenital foregut anomaly. The computed tomography (CT) findings revealed an unusually long segment of aberrant pancreatic lobe arising from the pancreatic neck, projecting anteriorly at a distance to a cystic duodenal duplication and appearing as an inflammatory mass. There has been no previous report of this unusual appearance on CT. Appreciation of the relevant anatomy provided by CT led to the successful management of this surgically-treatable cause of relapsing pancreatitis.

Cholesterol crystal embolization causing acute renal failure

Acute renal failure due to cholesterol embolization is a complication of severe generalized arteriosclerotic disease. It occurs spontaneously, or more often, as a complication of major medical or surgical procedures such as angiography and vascular surgery. The demonstration of characteristic cholesterol crystals in tissue biopsy specimens is a pathognomonic finding. However, renal cholesterol embolism may be clinically diagnosed when renal failure develops after known inciting factors or together with systemic manifestations of atheromatous embolization such as lower extremity livedo reticularis and focal digital ischemia. We report two cases of acute renal failure in which cholesterol embolization was found in skin and renal biopsies. One patient's renal function stabilized, but not to the basal level and the other patient developed end-stage renal disease.

Blunt trauma-induced internal thoracic artery injury: case report

We report the case of a 54-year-old male motorcyclist with an apparent grade IV liver injury and life-threatening hemomediastinum and right hemothorax following blunt deceleration trauma. Massive hemothorax and an unstable hemodynamic status even under copious blood volume replacement made emergent surgical intervention mandatory. A midline laparotomy was performed at first to rule out abdominal bleeding accompanied by a diaphragmatic tear, but the procedure was soon converted to a thoracotomy after finding an intact diaphragm and persistent bleeding from the chest tube. An isolated internal thoracic artery (ITA) transection was identified. It was actively bleeding and causing a huge anterior mediastinal hematoma and had ruptured into the right pleural cavity. The bleeder was controlled with suture ligation and the hemodynamic status was soon stabilized. The patient recovered without significant sequelae. The rarity of this kind of presentation is discussed, including both the ITA injury mechanism and the problems posed in making an early and correct diagnosis.

Purification of two secretin-releasing peptides structurally related to phospholipase A2 from canine pancreatic juice

We previously showed that canine pancreatic juice contains a secretin-releasing factor activity. In this study, we carried out isolation of two secretin-releasing peptides (SRPs) from canine pancreatic juice. Through ultrafiltration, anion and cation exchange, and reverse-phase high-performance liquid chromatography (HPLC) steps and an in vitro bioassay in STC-1 cells, two SRPs, SRP-1 and SRP-2, were isolated and purified to homogeneity. Both SRPs dose-dependently stimulated secretin release from STC-1 cells. The results of mass spectral analysis indicated that SRP-1 and SRP-2 had molecular masses of 14,061 Da and 14,053 Da, respectively. N-terminal amino acid sequence analysis indicated that SRP-1 was identical to canine pancreatic PLA2 in the 25 residues determined; whereas SRP-2 had 71% sequence homology to the enzyme in the first 21 residues. Commercially available porcine pancreatic PLA2 dose-dependently stimulated secretin release from STC-1 cells. Porcine pancreatic PLA2 also stimulated secretin release from a secretin-producing cells-enriched preparation isolated from rat duodenal mucosa. These results suggest that pancreatic PLA2 and its related peptide may participate in regulation of secretin secretion.

Video-assisted endoscopic removal of infected endocardial pacemaker lead with large floating vegetation

The best management of pacemaker lead related endocarditis is complete surgical or percutaneous removal of the pacemaker system. Although the traditional surgical approach is via median sternotomy, we present two cases in which the lead and vegetations were removed using a video-assisted endoscopic technique through a limited right submammary incision. In each case the patient was supported by partial extracorporeal perfusion. Additional tricuspid valve repair and atrial septal defect closure was performed in one case. The postoperative courses were uneventful, illustrating that, when compared to the conventional open heart surgical approach, the less invasive approach can be a safe and effective way to remove an infected foreign body from the right heart with increased comfort, fast recovery, and a better cosmetic result.

Thoracoscopic surgery for spontaneous pneumothorax

Spontaneous pneumothorax in apparently healthy individuals is a relatively common occurrence. The management of patients with spontaneous pneumothorax remains controversial. With the advances in thoracoscopic techniques and instrumentation, video-assisted thoracic surgery (VATS) is now accepted by many as the procedure of choice for surgical treatment of spontaneous pneumothorax. We report our combined experience with 757 patients who suffered from recurrent or persistent spontaneous pneumothorax treated by VATS over a 5-year period. Surgical indications included persistent air leak (n = 165), recurrence (n = 325), radiologically demonstrated huge bulla (n = 12), spontaneous hemopneumothorax (n = 13), incomplete expansion of the lung (n = 212), and bilateral involvement (n = 30). Several surgical procedures were undertaken, based on the thoracoscopic findings: endoscopic stapled bullectomy (n = 312), argon beam coagulation (n = 6), endoscopic suturing (n = 52), and endoloop ligation (n = 352). In 49 cases, mechanical or chemical pleurodesis was the only procedure performed. There were no mortalities or intraoperative hazards. Complications consisted of wound infections (n = 16), localized empyema (n = 2), chest wall bleeding (n = 1), and persistent air leaks (bulla type III) (n = 31). The median duration of the operation was 55 minutes (15-160 minutes), and the average postoperative hospital stay was 4.5 days (range 0-27 days). There were 16 recurrences (2.1%), after a mean follow-up of 30 months (range 1-60 months). Seven patients had recurrence from 9 to 17 months after stapled bullectomy. All the remaining patients had recurrence after failed pleurodesis. On the basis of our results, we conclude that video-assisted thoracoscopic management allows effective, safe performance of standard surgical procedures, avoiding a formal thoracotomy incision. We consider thoracoscopy the treatment of choice for patients with pneumothorax requiring surgical therapy.

The use of multiplane transesophageal echocardiography to evaluate residual patent ductus arteriosus during video-assisted thoracoscopy in adults

BACKGROUND

Video-assisted thoracoscopic surgery (VATS) has emerged as an innovative and popular procedure for interruption of patent ductus arteriosus (PDA), while intraoperative transesophageal echocardiography (TEE) has proven to be an effective monitor in the evaluation of residual patency. Previous reports on the adequacy of surgical interruption of PDA under VATS and TEE are available for pediatric patients, but only limited information is available for adults with PDA. MATEIALS AND METHODS: Between August 1995 and October 1997, we monitored 35 adult patients undergoing PDA interruption via VATS with Hewlett-Packard color Doppler multiplane TEE throughout the procedure. The average PDA diameter was 10.2 +/- 1.8 mm. All the PDA were completely ligated.

RESULTS

Thirty-two patients showed no ductal flow after double ligation. In the other three patients, residual flow was detected intraoperatively after double ligation, but it was quickly abolished by the third ligation. One patient showed faint ductal flow by transthoracic echocardiography at postoperative follow-up, but no reintervention was needed.

CONCLUSIONS

Our study showed that, with the refinement of adult PDA interruption via VATS, intraoperative multiplane TEE provides higher resolution for direct evaluation of the entire course of PDA ligation without interrupting the surgical procedure and minimizes the incidence of complications.

In vivo screening of haloalkane dehalogenase mutants

Haloalkane dehalogenase (Dh1A) from Xanthobacter autotrophicus GJ10 catalyzes the dehalogenation of short chain primary alkyl halides. Due to the high Km and low turnover, wild type Dh1A is not optimal for applications in bioremediation. We have developed an in vivo screen, based on a colorimetric pH indicator, to identify Dh1A mutant with improved catalytic activity. After screening 50,000 colonies, we identified a Dh1A mutant with a lower pH optimum. Sequence analysis of the mutant revealed a single substitution, alanine 149 to threonine, which is located close to the active site of Dh1A. Replacement of alanine 149 via site-directed mutagenesis with threonine, serine or cysteine retained the mutant phenotype. Other substitutions at position 149 show little or no activity.

Tuberculous pseudoaneurysm of the femoral artery: a case report

Pseudoaneurysm of the femoral artery is an extremely rare complication of tuberculosis. We present a case of tuberculous femoral pseudoaneurysm that was successfully treated with resection, direct anastomosis, and postoperative antituberculous chemotherapy.

The anti-inflammatory and hepatoprotective effects of fractions from Cudrania cochinchinensis var. gerontogea

Various fractions of the ethanol extract from the root wood of Cudrania cochinchinensis var. gerontogea (Moraceae) were evaluated for their anti-inflammatory effects on carrageenan-induced edema and hepatoprotective activities on carbon tetrachloride (CCl4)-induced and D-galactosamine-(D-GalN) induced acute hepatotoxicity in rats. The fractions (n-hexane, CHCl3, EtOAc, n-BuOH, and H2O) displayed significant inhibitory activity against carrageenan-induced edema, and the active anti-inflammatory components were further localized in the n-BuOH fraction, which exhibited the greatest anti-inflammatory effect, an effect 5% greater than indomethacin (which was used as a standard reference substance). Each fraction exerted a significant hepatoprotective effect by reducing enzymatic alteration (sGOT and sGPT) and by improving hepatic lesions, including liver centrilobular inflammation, cell necrosis, fatty change, ballooning degeneration in CCl4-induced acute hepatitis; and necrosis of the portal area in D-GalN-induced acute liver injury. The n-BuOH and EtOAc fractions had the greatest hepatoprotective effects on CCl4-induced liver injury; in contrast, the CHCl3 fraction was most potent against D-GalN intoxication, which is comparable to silymarin, as a recognized hepatoprotective drug.

Emphysema surgery--loop ligation approach

OBJECTIVES

To demonstrate the efficacy of using thoracoscopic endoloop ligation of bullae in patients with bullous emphysema.

METHODS

From 1992 to 1997, 93 advanced age (mean age, 66 years) and oxygen dependency patients underwent thoracoscopic procedure using endoloop ligation for treatment of bullous emphysema. Clinical data were collected from chart review. Thoracoscopic loop ligation of bulla was carried out under general anesthesia with double lumen endotracheal tube and single lung ventilation.

RESULTS

Eighty-two patients (88%) exhibited subjective improvement in their symptom status at 3-month follow-up (from grade 2 or 3 to grade 1 or 2) according to the modified Medical Research Council dyspnea scale. The mean duration of chest drainage was 7.5 days (range, 4-19 days). Average hospital stay was 9.5 (range, 5-26) days. There was no post-operative death. A comparison of pre-operative and post-operative functional evaluation was available in 27 patients who showed an average increase in FEV1 (from 0.89 to 1.12 l) and declined in residual volume after operation. Complications include persistent airleak over 10 days in nine patients (9.7%), wound infection in three patients and localized empyema in five patients. There was no recurrent after a mean follow-up of 37 months.

CONCLUSION

Thoracoscopic loop ligation of bulla has proven to be a safe, reliable and cost effective means of technique for bullous emphysema.

Blunt trauma with flail chest and penetrating aortic injury

Blunt chest trauma with flail chest is common. The mortality attributes initially to the associated pulmonary contusion, massive hemothorax and later to the occurrence of adult respiratory distress syndrome. We report a case of flail chest with segmental fractures near the costovertebral junction and delayed hemothorax attacked 14 h later. The final diagnosis of the penetrating aortic injury by detached rib fragment was appreciated by aortogram. Unfortunately, active aortic hemorrhage made prompt thoracotomy in vain for life salvage.

HIV protease drug resistance and its impact on inhibitor design

The primary cause of resistance to the currently available HIV protease inhibitors is the accumulation of multiple mutations in the viral protease. So far more than 20 substitutions have been observed in the active site, dimer interface, surface loops and flaps of the homodimer. While many mutations reduce the protease's affinity for inhibitors, others appear to enhance its catalytic efficiency. This high degree of genetic flexibility has made the protease an elusive drug target. The design of the next generation of HIV protease inhibitors will be discussed in light of the current structural information.

"I" ministernotomy for aortic valve replacement

BACKGROUND

Minimally invasive surgical approaches have been applied recently in the management of valvular heart disease. In this report, we reviewed our preliminary experience of minimally invasive aortic valve replacement.

METHODS

Eighteen patients were operated on by means of an "I" ministernotomy, and 16 patients were operated on by means of a full median sternotomy during the same period. There was no difference between these two groups in term of age, sex, and preoperative left ventricular ejection fraction. In patients of the ministernotomy group, the operations were approached through an "I" median sternal split, from the second to the fifth intercostal space, 8 to 10 cm in length, with transverse division. Cardiopulmonary bypass was established through aorto-right atrial cannulation with aortic cross-clamping and antegrade or retrograde delivery of blood cardioplegia.

RESULTS

Under direct vision, aortic valve replacement was performed successfully in patients of both groups. The duration of cardiopulmonary bypass time and aortic cross-clamp time was significantly longer in the ministernotomy group than in the full sternotomy group. However, the length of incision, duration of endotracheal intubation, intensive care unit stay, pain score, postoperative length of stay, and return to normal activity interval were significantly shorter and lower in patients of the ministernotomy group than in those of the full sternotomy group. All patients recovered from the operation rapidly. Follow-up was complete in all patients with no late complications. Echocardiographic examination showed good function of aortic prostheses.

CONCLUSIONS

Our experience demonstrates that the "I" ministernotomy provides good exposure, reduced wound pain, enhanced recovery, shortened hospital stay, and good cosmetic healing. It may be a good alternative for surgical correction of aortic valve lesions.

Exon 4-encoded acidic domain in the epithelium-restricted Ets factor, ESX, confers potent transactivating capacity and binds to TATA-binding protein (TBP)

The Ets gene family has a complex evolutionary history with many family members known to regulate genetic programs essential for differentiation and development, and some known for their involvement in human tumorigenesis. To understand the biological properties associated with a recently described epithelium-restricted Ets factor ESX, an 11 kb fragment from the 1q32.2 genomically localized human gene was cloned and analysed. Upstream of the ESX promoter region in this genomic fragment lies the terminal exon of a newly identified gene that encodes a ubiquitin-conjugating enzyme variant, UEV-1. Tissues expressing ESX produce a primary 2.2 kb transcript along with a 4.1 kb secondary transcript arising by alternate poly(A) site selection and uniquely recognized by a genomic probe from the 3' terminal region of the 11 kb clone. Endogenous expression of ESX results in a 42 kDa nuclear protein having fivefold greater affinity for the chromatin-nuclear matrix compartment as compared to other endogenous transcription factors like AP-2 and the homologous Ets factor, ELF-1. Exon mapping of the modular structure inferred from ESX cDNA and construction of GAL4(DBD)-ESX expression constructs were used to identify a transactivating domain encoded by exon 4 having comparable potency to the acidic transactivation domain of the viral transcription factor, VP16. This exon 4-encoded 31 amino acid domain in ESX was shown by mutation and deletion analysis to possess a 13 residue acidic transactivation core which, based on modeling and circular dichroism analysis, is predicted to form an amphipathic alpha-helical secondary structure. Using recombinant GST-ESX (exon 4) fusion proteins in an in vitro pull-down assay, this ESX transactivation domain was shown to bind specifically to one component of the general transcription machinery, TATA-binding protein (TBP). Transient transfection experiments confirmed the ability of this TBP-binding transactivation domain in ESX to squelch heterologous promoters independent of any promoter binding as efficiently as the transactivation domain from VP16.

Sensitization of stereotyped behavior to amphetamine is context and response dependent

The present study was designed to determine whether the environmental context in which amphetamine is administered plays a role in the development of sensitization to the stereotyped behavioral effects of amphetamine in mice. In male CF-1 mice, the dose-response curve for stereotyped behavior elicited by amphetamine was shifted 1.9-fold to the left 48 h after pretreatment with 14 mg/kg amphetamine. Behavioral sensitization only developed in mice that were pretreated in the same or a similar environment as that of the test environment. In addition, when mice were placed in an environment that attenuated the acute expression of stereotyped behavior elicited by the pretreatment dose of amphetamine, sensitization never developed. A further experiment showed that 96% of the mice that expressed stereotypy after the ED50 pretreatment dose of 10 mg/kg amphetamine showed a stereotyped behavioral response to the lesser dose of 7 mg/kg 48 h later, indicating sensitization. In contrast, mice that did not express stereotypy after the ED50 dose of amphetamine failed to show a significant stereotyped behavioral response to amphetamine challenge compared to vehicle-pretreated controls. Therefore, the results indicate that preexposure to a single high dose of amphetamine produces context- and response-dependent sensitization to amphetamine-induced stereotyped behavior.

Automatic finite element mesh generation for maxillary second premolar

Developing three dimensional finite element mesh models for irregular geometric objects requires a large amount of manual efforts, hence limiting the three dimensional approach for dental structure analyses. An automatic procedure which can be used to generate a three dimensional finite element mesh for the maxillary second premolar was developed in this study. Firstly, a embedded second premolar was sliced and scanned parallel to the occlusal surface. A self-developed image processing system was employed to detect the boundaries of different materials within each section. An automatic mesh generation program was used on these boundaries to create tetrahedral elements based on moving nodes of uniform cube approach. Six mesh models of the second premolar with different element sizes using linear and quadratic elements were analyzed. Strain energy and von Mises stresses were reviewed for convergence in the crown regions.

Immature teratomas of the genital tract in older women

We report the clinicopathologic features of three women, 40 years of age or older, with malignant genital tract immature teratomas. All had FIGO stage III, grade II or grade III tumors. One tumor arose from the fallopian tube, the second from the ovary, and the third involved the cortical surfaces of both ovaries with minimal parenchymal involvement. The tumors weighed 1700, 5660, and 330 g and had histologic features similar to those generally seen in younger women. Two of the women died within 1 year of diagnosis. Interval growth of tumor after treatment with chemotherapy was documented in the third patient; she was reexplored and all of the excised tumor was composed of mature tissues. These cases affirm that, although rare, malignant germ cell tumors can occur in older peri- or postmenopausal women.

Haloalkane dehalogenases: steady-state kinetics and halide inhibition

The substrate specificities and product inhibition patterns of haloalkane dehalogenases from Xanthobacter autotrophicus GJ10 (XaDHL) and Rhodococcus rhodochrous (RrDHL) have been compared using a pH-indicator dye assay. In contrast to XaDHL, RrDHL is efficient toward secondary alkyl halides. Using steady-state kinetics, we have shown that halides are uncompetitive inhibitors of XaDHL with 1, 2-dichloroethane as the varied substrate at pH 8.2 (Cl-, Kii = 19 +/- 0.91; Br-, Kii = 2.5 +/- 0.19 mM; I-, Kii = 4.1 +/- 0.43 mM). Because they are uncompetitive with the substrate, halide ions do not bind to the free form of the enzyme; therefore, halide ions cannot be the last product released from the enzyme. The Kii for chloride was pH dependent and decreased more than 20-fold from 61 mM at pH 8.9 to 2.9 mM at pH 6.5. The pH dependence of 1/Kii showed simple titration behavior that fit to a pKa of approximately 7.5. The kcat was maximal at pH 8.2 and decreased at lower pH. A titration of kcat versus pH also fits to a pKa of approximately 7.5. Taken together, these data suggest that chloride binding and kcat are affected by the same ionizable group, likely the imidazole of a histidyl residue. In contrast, halides do not inhibit RrDHL. The Rhodococcus enzyme does not contain a tryptophan corresponding to W175 of XaDHL, which has been implicated in halide ion binding. The site-directed mutants W175F and W175Y of XaDHL were prepared and tested for halide ion inhibition. Halides do not inhibit either W175F or W175Y XaDHL.

Porcine pancreatic phospholipase A2 stimulates secretin release from secretin-producing cells

We have isolated, from canine pancreatic juice, two 14-kDa proteins with secretin-releasing activity that had N-terminal sequence homology with canine pancreatic phospholipase A2 (PLA2). In this study we have obtained evidence that secretin-releasing activity is an intrinsic property of pancreatic PLA2. Porcine pancreatic PLA2 from Sigma or Boehringer Mannheim was fractionated into several peaks by reverse phase high performance liquid chromatography. They were tested for stimulation of secretin release from murine neuroendocrine intestinal tumor cell line STC-1 and secretin cells enriched mucosal cell preparations isolated from rat upper small intestine. Each enzyme preparation was found to contain several components of secretin-releasing activity. Each bioactive fraction was purified to homogeneity by rechromatography and then subjected to mass spectral analysis and assays of PLA2 and secretin-releasing activities. It was found that the fraction with highest enzymatic activity also had the highest secretin-releasing activity and the same Mr as porcine pancreatic PLA2. Moreover, it also had the same N-terminal amino acid sequence (up to 30 residues determined) as that of porcine pancreatic PLA2, suggesting that it was identical to the enzyme. Purified porcine pancreatic PLA2 also stimulated secretin release concentration-dependently from both STC-1 cells and a mucosal cell preparation enriched in secretin-containing endocrine cells isolated from rat duodenum. Abolishment of the enzymatic activity by pretreatment with bromophenacyl bromide did not affect its secretin-releasing activity. The stimulatory effect of purified pancreatic PLA2 on secretin secretion from STC-1 cells was inhibited by an L-type Ca2+ channel blocker, by down-regulation of protein kinase C or by pretreatment of the cell with pertussis toxin. It is concluded that porcine pancreatic PLA2 possesses an intrinsic secretin-releasing activity that was independent of its enzymatic activity. This action is pertussis toxin-sensitive and is in part dependent on Ca2+ influx through the L-type channel and activation of protein kinase C.

Pancreatic infiltration but not diabetes occurs in the relative absence of MHC class II-restricted CD4 T cells: studies using NOD/CIITA-deficient mice

The NOD (nonobese diabetic) mouse is a good animal model for human IDDM. MHC class II-restricted CD4 T cells are necessary for the onset of diabetes in NOD mice. Here, we demonstrate that NOD mice lacking the CIITA (class II transactivator) molecule, and hence deficient in MHC class II expression and peripheral CD4 T cells, show significant pancreatic infiltration but do not develop diabetes. CD4 T cell deficiency, then, does not prevent initial pancreatic infiltration, but does stop progression to insulitis. Adoptive transfer studies show that the paucity of CD4 T cells in NOD-CIITA knockout mice is responsible for the absence of diabetes, since the CD8 T cell and B cell compartments are functional. An autoaggressive CD8+ T cell clone can, however, transfer diabetes in CIITA knockout recipient mice without CD4 T cell help, albeit with some delay compared with that in CIITA-sufficient recipients. This highlights the fact that a high number of in vitro activated autoaggressive CD8 T cells can over-ride the requirement for CD4 T cell help for the onset of diabetes.

Microvascular prefabricated free skin flaps for esophageal reconstruction in difficult patients

BACKGROUND

Reconstruction of the esophagus for complicated benign stricture or after resection of malignant lesion is still a challenge for surgeons. When abdominal viscera cannot be used, skin flaps are selected for esophageal reconstruction. However, skin flaps for esophageal reconstruction are notorious for leakage, and have not been widely accepted. Prefabrication before microvascular transfer to its final site can improve the result of esophageal reconstruction when skin flaps are used.

METHODS

Eight patients with complicated corrosive esophagitis had been treated with prefabricated skin flaps for esophageal reconstruction. The procedures are described in detail.

RESULTS

All patients healed well without leakage. The barium study showed smooth passage. There was no dysphasia or regurgitation after education. Pulmonary complication happened in only 1 patient. Revision for the distal anastomosis was required in 1 patient due to narrowing. When the skin tube is long, the patients need water (or soup) to facilitate swallowing and occasionally use their hand to help the food passage. This method has the following advantages: (1) healing of the long suture line before transfer to withstand the intestinal juice; (2) reliable viability in the distal part of the flap, especially when an extended length of the flap is required; (3) more length of stable tissue for two-layered, tension-free anastomosis at the junction of skin and gastrointestinal mucosa to prevent leakage; and (4) the flap can be placed in the substernal position to meet the aesthetic requirement of young patients. The disadvantage was the staged operations. However, after prefabrication the transfer becomes safe and free of leakage. The overall morbidity is minimal.

CONCLUSIONS

In rare situations when skin flaps are used for esophageal reconstruction, prefabrication provides advantages over conventional one-stage methods, although it needs additional procedures. This method is a combination of conventional technique and microsurgery.

Crystallization and preliminary X-ray diffraction data of the complex of recombinant tick anticoagulant peptide (rTAP) and bovine factor Xa

The complex of bovine factor Xa and recombinant tick anticoagulant peptide (rTAP) was crystallized in two different crystal forms using polyethylene glycol as a precipitant. Form I belongs to space group P42212 with unit-cell dimensions a = b = 133.1, c = 68.8 A. It contains one complex per asymmetric unit and diffracts to 3.0 A resolution. Form II belongs to P41212 (or P43212) with dimensions a = b = 126.5, c = 146.7 A; it contains two complexes per asymmetric unit and diffracts to 2.5 A. The crystals of both forms consist of factor Xa (MW = 45.3 kDa) and rTAP (MW = 6.7 kDa).

Kimura's disease of bilateral upper eyelids: a case report

We present a rare case of Kimura's disease of bilateral upper eyelids. A 41-year-old Chinese male had multiple masses over retroauricular, submandibular regions and bilateral upper eyelids since 13 years previously. Tumor recurred after each surgical excision, chemotherapy and Co 60 radiotherapy. Eosinophilia and elevation of blood immunoglobulin E (IgE) were noted in this admission. We operated on left upper eyelid to relieve the blocking of vision. A diffuse infiltration with numerous fibrotic bands was noted. Histological section showed a lymphoid hyperplasia, remarkable infiltration of eosinophils and proliferation of capillaries. Oral prednisolone 60 mg was given postoperatively. The patient had a satisfactory appearance and a relief of visual block.

Pharmacology of LY315920/S-5920, [[3-(aminooxoacetyl)-2-ethyl-1- (phenylmethyl)-1H-indol-4-yl]oxy] acetate, a potent and selective secretory phospholipase A2 inhibitor: A new class of anti-inflammatory drugs, SPI

LY315920 is a potent, selective inhibitor of recombinant human, group IIA, nonpancreatic secretory PLA2 (sPLA2). In a chromogenic isolated enzyme assay, LY315920 inhibited sPLA2 activity with an IC50 of 9 +/- 1 nM or 7.3 x 10(-6) mole fraction, which approached the stiochiometric limit of this assay. The true potency of LY315920 was defined using a deoxycholate/phosphatidylcholine assay with a mole fraction of 1.5 x 10(-6). LY315920 was 40-fold less active against human, group IB, pancreatic sPLA2 and was inactive against cytosolic PLA2 and the constitutive and inducible forms of cyclooxygenase. Human sPLA2-induced release of thromboxane A2 (TXA2) from isolated guinea pig lung bronchoalveolar lavage cells was inhibited by LY315920 with an IC50 of 0.79 microM. The release of TXA2 from these cells by N-formyl-methionyl-leucyl-phenylalanine or arachidonic acid was not inhibited. The i.v. administration of LY315920, 5 min before harvesting the bronchoalveolar lavage cells, resulted in the inhibition of sPLA2-induced production of TXA2 with an ED50 of 16.1 mg/kg. Challenge of guinea pig lung pleural strips with sPLA2 produced contractile responses that were suppressed in a concentration-dependent manner by LY315920 with an apparent KB of 83 +/- 14 nM. Contractile responses induced by arachidonic acid were not altered. Intravenous or oral administration of LY315920 to transgenic mice expressing the human sPLA2 protein inhibited serum sPLA2 activity in a dose-related manner over a 4-h time course. LY315920 is a potent and selective sPLA2 inhibitor and represents a new class of anti-inflammatory agent designated SPI. This agent is currently undergoing clinical evaluation and should help to define the role of sPLA2 in various inflammatory disease states.

A novel role for the major histocompatibility complex class II transactivator CIITA in the repression of IL-4 production

Class II transactivator (CIITA) is known as a coactivator for MHC class II gene expression in antigen-presenting cells. Surprisingly, when CIITA-/- CD4 T cells were stimulated in the presence of IL-12, they produced not only IFNgamma but also high levels of IL-4. The IL-4 production is due to the accumulation of IL-4 gene transcripts in Th1 cells. This transcriptional control is observed in T cells differentiating to the Th1 but not Th2 lineage, consistent with induction of expression of the CIITA gene in T cells by IFNgamma. Thus, in addition to its role in transactivation of genes involved in antigen presentation, CIITA plays a critical role during the T cell differentiation by negatively regulating the IL-4 gene transcription.

Thoracoscopic retrieval of foreign body after penetrating chest injury: report of two cases

Video-assisted thoracic surgery has proved to be valuable in many settings in thoracic surgery. The use of video-assisted thoracic surgery in trauma has recently rapidly increased. It is useful in acute or delayed management of patients with blunt and penetrating chest trauma. It is safe for removal of clotted hemothorax, treatment of thoracic empyema, treatment of persistent pneumothorax, treatment of chylothorax, and for diagnosis of diaphragmatic injury. We report two cases using thoracoscopy to remove intrathoracic metal fragments and avert the need for thoracotomy. In the first patient, a metal fragment injury was sustained via a penetrating wound from the supraclavicular notch to the right upper lung. The metal fragment was retrieved and the lung was repaired thoracoscopically using conventional suturing techniques. A second patient sustained a broken pin injury to the left upper mediastinum via a low neck wound. The pin was successfully removed under videothoracoscopy. Both patients recovered uneventfully and had shortened hospital stays. We feel that thoracoscopy offers a therapeutic as well as diagnostic benefit in stable patients with penetrating chest trauma.

Effects of hyperoxia on nitric oxide synthase expression, nitric oxide activity, and lung injury in rat pups

Although hyperoxic exposure is an important contributor to the development of bronchopulmonary dysplasia and nitric oxide (NO) has been implicated in the pulmonary response to oxygen, the role of NO in mediating chronic neonatal lung injury is unclear. Therefore, rat pups were exposed to normoxia or hyperoxia (>95% O2) from d 21 to 29. After the rats were killed, their lungs were removed for analysis of nitric oxide synthase (NOS) expression, NO activity as measured by 3',5'-cyclic guanosine monophosphate (cGMP) assay, and lung pathology. Hyperoxia caused 5-fold and 2-fold increases in inducible (i) NOS and endothelial (e) NOS levels, respectively. NO activity was assessed by measuring cGMP levels after normoxic or hyperoxic exposure in the presence and absence of NOS blockade with either aminoguanidine (AG) or Nomega-nitro-L-arginine (L-NNA). cGMP levels were elevated in hyperoxic versus normoxic rats (287+/-15 versus 106+/-9 pmol/mg protein, respectively, p < 0.001), and this increase in cGMP was attenuated after NOS blockade with either AG or L-NNA. Hyperoxic exposure significantly increased lung/body weight ratios and induced histologic changes of interstitial and alveolar edema; however, these hyperoxia-induced histologic changes were not altered by NOS blockade with AG or L-NNA. We conclude that hyperoxic exposure of rat pups up-regulated both iNOS and eNOS and increased NO activity as measured by cGMP levels derived from both iNOS and eNOS. Blockade of NOS reduced cGMP levels in the hyperoxic rat pups; however, it did not seem to reverse the pathologic consequences of hyperoxic exposure.

Symptom patterns of premenstrual dysphoric disorder as defined in the Diagnostic and Statistical Manual of Mental Disorders-IV

Premenstrual dysphoric disorder was included in an appendix of DSM-III-R (revised third edition of the Diagnostic and Statistical Manual of Mental Disorders) and DSM-IV to facilitate systematic research. Items contained in its set of research criteria were considered tentative. Only one previous study of premenstrual symptoms specifically addressed symptoms of premenstrual dysphoric disorder, and it did not use DSM-IV criteria. In the present study, prospectively measured symptoms of 99 women were analyzed using exploratory principal components analysis with orthogonal rotation on all 24 items derived from the 11 symptoms listed in DSM-IV. Variation was found across phases of cycle and groups, with five factors predominating: (1) anger/irritability, (2) depressed mood, (3) anxiety/tension, (4) decreased energy and interest with physical symptoms, and (5) eating problems.

Korean Nationwide Surveillance of Antimicrobial Resistance of bacteria in 1997

Antimicrobial-resistant bacteria are known to be prevalent in tertiary-care hospitals in Korea. Twenty hospitals participated to this surveillance to determine the nationwide prevalence of resistance bacteria in 1997. Seven per cent and 26% of Escherichia coli and Klebsiella pneumoniae were resistant to 3rd-generation cephalosporin. Increased resistance rates, 19% of Acinetobacter baumannii to ampicillin/sulbactam, and 17% of Pseudomonas aeruginoa to imipenem, were noted. The resistance rate to fluoroquinolone rose to 24% in E. coli, 56% in A. baumannii and 42% in P. aeruginosa. Mean resistance rates were similar in all hospital groups: about 17% of P. aeruginosa to imipenem, 50% of Haemophilus influenzae to ampicillin, 70% of Staphylococcus aureus to methicillin, and 70% of pneumococci to penicillin. In conclusion, nosocomial pathogens and problem resistant organisms are prevalent in smaller hospitals too, indicating nosocomial spread is a significant cause of the increasing prevalence of resistant bacteria in Korea.

HLA-DRB1*0701 and DRB1*1401 are associated with genetic susceptibility to psoriasis vulgaris in a Taiwanese population

We analysed the allelic frequencies of class II human leucocyte antigen (HLA)-DRB1, DQA1, DQB1 and DPB1 by polymerase chain reaction/sequence-specific oligonucleotide probe hybridization typing in 76 Taiwanese psoriasis vulgaris (PSV) patients and 238 Taiwanese non-psoriatic controls. The analysis revealed the following: (i) the DRB1*0701 allele was positively associated with PSV (relative risk, RR = 6.4, corrected P-value, Pc < or = 0.001); (ii) the DRB1*1401 allele was positively associated with type I PSV (age at onset < 40 years) (RR = 3.5, Pc < or = 0.001); (iii) the DQA1*0501 allele was negatively associated with PSV (RR = 0.4, Pc < or = 0.001); (iv) there was no significant association of HLA-DP genes with PSV; and (v) there was a strong association of beta-chain phenylalanine at position 37 (Phe 37) and glutamate or glutamine at position 74 (Glu 74/Gln 74) with PSV (RR = 3.5, Pc < or = 0.001 for the association of Phe 37 with PSV: RR = 2.2, Pc < or = 0.001 for the association of Glu 74/Gln 74 with PSV). The positive association between PSV and the DRB1*0701 allele is consistent with previous reports. The negative association of the DQA1*0501 allele is reported only in Finland, whereas the positive association between PSV and the DRB1*1401 allele has never been described before. Trans-racial studies may shed further light on the association of class II HLA alleles or other closely linked genes with the development of PSV. Phe 37 (a large, non-polar amino acid) and Glu 74/Gln 74 (both negatively charged amino acids) were the polymorphic residues in pockets 9 and 4, respectively, of the beta-chain, which may have increased their affinity for the small non-polar amino acids and basic amino acids of the psoriatic antigen peptide, thereby activating the T lymphocytes. This finding may facilitate the identification of a psoriatic antigen.

Mice lacking the transcription factor CIITA--a second look

We have generated a second line of mice lacking a transcription factor thought to be a critical regulator of MHC class II gene expression, CIITA (for class II transactivator). Our and the previously published lines differ in the deletion that was engineered and by the fact that we removed the neomycin-resistance promoter and structural gene via the cre-loxP recombination system. Characterization of our line led to two new findings. First, a substantial number of cells can express class II molecules in the absence of CIITA, albeit at 5-fold reduced levels, most notably dendritic cells in s.c. lymph nodes; therefore, the CIITA gene cannot be an absolute 'master gene' controlling the expression of class II molecules, as had been thought. Second, in contrast to recent results on human cell lines, CIITA is not critically involved in the IFN-gamma-induced up-regulation of MHC class I genes.

Stimulation of membrane-bound guanylate cyclase activity by 17-beta estradiol

Estrogen is known to exert both long-term genomic and short-term nongenomic actions. The long-term genomic actions of estrogen are mediated by the binding of estrogen to its cytoplasmic/nuclear receptor that subsequently triggers the transcription of target genes. In contrast, little is known about the molecular basis of the nongenomic actions of estrogen. We have found that 17-beta estradiol activates membrane-bound guanylate cyclase and enhances atrial natriuretic factor (ANF)-stimulated guanylate cyclase activity in PC12 cell membranes. Membrane-bound guanylate cyclase, GC-A, contains an extracellular ANF-binding domain and an intracellular kinase-like domain plus catalytic domain. The kinase-like domain plus the catalytic domain of guanylate cyclase (GC-kc) can be expressed in E. Coli and functionally renatured. 17-beta estradiol also activates the bacteria expressed GC-kc, indicating that 17-beta estradiol can directly interact with membrane-bound guanylate cyclase. These results demonstrate that 17-beta estradiol exerts a non-genomic action on membrane-bound guanylate cyclase.

Oxidant stress impaired DNA-binding of estrogen receptor from human breast cancer

Full-length (67 kDa) immunoreactive estrogen receptor (ER) extracted from a third of untreated ER-positive primary breast tumors appears unable to bind to its cognate estrogen response element (ERE). We have observed partial reversibility of this ER DNA-binding defect upon treatment of these tumor extracts with excess thiol reducing agent (DTT), suggesting that ER DNA-binding is subject to redox modulation as is reported for other zinc-finger proteins and transcriptional activators. Treatment of recombinant ER DNA-binding domain (ER-DBD) or ER-enriched extracts from CHO(ER) and MCF-7 cells with thiol-reacting oxidants (diamide, iodosobenzoate, H2O2) or alkylator (iodoacetamide) produces a dose-dependent loss in ER DNA-binding capacity. Thiol-specific oxidative loss in ER DNA-binding is fully reversible by DTT reduction, unlike the defect caused by thiol-specific alkylation. Circular dichroism spectrometry shows that both forms of treatment substantially modify ER secondary structure, inducing loss of alpha-helical content within the ER-DBD that is reversible after thiol oxidation but not after thiol alkylation. Oxidant (H2O2, menadione) exposure of cultured CHO(ER) or MCF-7 cells impairs the ability of endogenous ER to bind DNA and transactivate an ER-responsive reporter gene (ERE-tk-CAT), demonstrating that extracellular redox stress can modulate intracellular ER function. Since these thiol-specific oxidant and alkylator treatments have no significant effect on either recombinant ER ligand-binding or intracellular immunoreactive ER content, our findings suggest that DNA-binding and transactivation are the most sensitive intracellular ER functions impaired by oxidant stress in some ER-positive human breast tumors.

Central retinal vein occlusion associated with cryofibrinogenemia in a young adult--study of skin dynamic capillaroscopy

A 26-year-old woman presented with a 2-month history of intermittent dim vision in her right eye and a diagnosis of central retinal vein occlusion (CRVO) was made. Investigations revealed Raynaud's phenomenon and cryofibrinogenemia. Skin capillaroscopy revealed tortuous vessels and decreased capillary blood-cell velocity in the capillaries of her finger nail fold which coincided with the CRVO attack. After treatment with oral aspirin for 3 months, the CRVO subsided, the capillary blood-cell velocity in the nail fold improved, and serum cryofibrinogen was undetectable. The time course of the cryofibrinogenemia and skin capillaroscopic findings correlated well with her ocular presentations. Study of cryofibrinogen should be included in the evaluation of young adults with CRVO.