Oxidative stress promotes autophagic cell death in human neuroblastoma cells with ectopic transfer of mitochondrial PPP2R2B (Bbeta2)

Background

The multifunctional protein phosphatase 2A (PP2A) is a heterotrimeric serine/threonine protein phosphatase composed of a scaffolding, catalytic and regulatory subunits. By modifying various downstream signal transducers, the aberrant expression of the brain-targeted regulatory subunit PPP2R2B is associated with the onset of a panel of neuronal disorders. The alternatively splicing of PPP2R2B encodes two regulatory subunit isoforms that determine cellular distribution of the neuron-specific holoenzyme to mitochondria (Bβ2) and cytoplasm (Bβ1), respectively.

Results

Human neuroblastoma cells were transfected with PPP2R2B constructs encoding the complete sequences of Bβ2 and Bβ1, respectively. The colonies with antibiotic resistance were selected as stable cell lines. Both ectopic Bβ1 and Bβ2 clones exhibited characteristics of autophagy. To test how cells respond to reactive oxygen species generators, the cells were treated with either hydrogen peroxide or t-butyl hydroperoxide and Bβ2 clones induced cell death. Suppression of autophagy using either RNA interference of the essential autophagy gene or pharmacological inhibitor rescued cell death caused by oxidative stress.

Conclusions

Cells with ectopically expressed mitochondria-targeted regulatory subunit PPP2R2B of the holoenzyme PP2A were shown predisposed to autophagy and oxidative stress induced cell death that is related to apoptosis. The results promised a model for studying the mechanism and function of aberrant PPP2R2B expression in neuronal cells. The work provided a new target for understanding and prevention of neuropathogenesis.

Human gastric cells resistant to (−)-epigallocatechin gallate show cross-resistance to several environmental pollutants

After a long-term culture in (-)-epigallocatechin gallate (EGCG, 20 microM), a major constituent of green tea, human gastric AGS cells developed 2.2-fold resistance to EGCG. The resistant AGS (AGS-R) cells were cross-resistant to several N-methylcarbamate insecticides, which are among the major control agents for pest insects in Taiwan. The AGS-R cells also showed protective effects against both the cytotoxicity and DNA damage induced by one of the mutagenic derivatives of N-methylcarbamate insecticide, N-nitroso methomyl, which is known to target the mammalian gastric tract. Therefore, acquisition of resistance by AGS cells through chronic exposure to EGCG implies that the tea-drinking habit of the Taiwanese is probably beneficial for the health of the gastric tract. In addition, AGS-R cells were cross-resistant to sodium arsenite and hydrogen peroxide, indicating that tolerance to oxidative stress might play a role in the development of resistance described in this investigation.

Effective Structure Factor of Osmotically Deformed Nanoemulsions

Extreme osmotic compression of nanoemulsion droplets, achieved by ultracentrifugation, can create solidlike biliquid foams without causing significant droplet coalescence. Using small-angle neutron scattering (SANS), we probe the structure of a uniform silicone oil-in-water nanoemulsion stabilized by sodium dodecyl sulfate over a wide range of volume fractions, phi, up to and beyond the limit associated with maximal random jamming of spheres, phiMRJ = 0.64. Although some features in the structure can be understood at lower phi using simple predictions for hard spheres, the anionic repulsion and deformability of the droplet interfaces creates departures from these predictions at higher phi. For phi near and beyond phiMRJ, the effective structure factor, Seff, as a function of wavenumber, q, exhibits a primary peak that is subunity. We speculate that this striking feature is due to the deformation of the droplets into nonspherical shapes as the system begins to approach the limit of a random array of nanoscopic thin films, Plateau borders, and vertexes characteristic of a polyhedral foam.

Dense cluster formation during aggregation and gelation of attractive slippery nanoemulsion droplets

Using time-resolved small angle neutron scattering, we have measured the wave-number-dependent structure factor S(q) of monodisperse nanoemulsions that aggregate and gel after we suddenly turn on a strong, short-range, slippery attraction between the droplets. At high q, peaks in S(q) appear as dense clusters of droplets form, and S(q) increases strongly toward low q, as these dense clusters become locked into a rigid gel network, despite the fluidity of the films between the droplets. The long-time high-q structure of nanoemulsion gels formed by slippery diffusion-limited cluster aggregation is universal in shape and remarkably independent of the droplet volume fraction, phi.

Structure of concentrated nanoemulsions

We use extreme shear to create a dispersion of nanoscale droplets of silicone oil in an immiscible water phase containing an anionic surfactant sodium dodecylsulfate. Using centrifugal size fractionation, we obtain nanoemulsions having a well-defined average radius of a=75 nm. We measure the structure of concentrated nanoemulsions over a wide range of volume fractions, 0<phi<0.6, using small angle neutron scattering, and we determine the structure factor S(q) of disordered glassy dispersions of uniform deformable droplets interacting through screened surface charge repulsions. Although the low-q behavior of S(q,phi) resembles that predicted for hard spheres, the height of the primary peak does not. Instead, it exhibits a maximum as phi is increased. This difference cannot be explained solely by the droplet size polydispersity and is likely related to the deformability of the droplets that have been locked into a glassy structure.

Density profiles of temperature-sensitive microgel particles

We have performed small angle neutron scattering measurements (SANS) on dilute aqueous dispersions of polymer microgel particles as a function of temperature, T . The microgel particles are spherical crosslinked assemblies of a loose gel network of a poly-N-isopropylacrylamide (NIPAM) polymer. When the temperature is raised beyond a critical temperature, T(lc) approximately 32 degrees C , the polymer becomes more strongly attracted to itself than the solvent, and the microgel particles contract. The measured form factor, F (q) , for dilute suspensions of uniform microgel particles exhibits many peaks that are characteristic of solid polymer nanospheres. The position and amplitude of the peaks as a function of wave number, q , provide insight into the density profile of poly-NIPAM within the microgels. These peaks can be described well over a wide range of temperature by a model of the polymer density within the particles that is constant up to an inner radius, R1 , and decreases linearly to zero at an outer radius, R2 .

Genetic diversity and biogeography of Cunninghamia konishii (Cupressaceae), an island species in Taiwan: a comparison with Cunninghamia lanceolata, a mainland species in China

Luanta-fir (Cunninghamia konishii), an endemic to Taiwan, is an outcrossing, long-lived conifer. Populations of C. konishii are generally fragmented due to a once high intensity of timber exploitation. C. konishii and Cunninghamia lanceolata are two sibling taxa constituting derivative-progenitor species relationship. The amount of genetic variations within and between 11 and 10 populations of C. konishii and C. lanceolata, respectively, were assessed using amplified fragment length polymorphism (AFLP) markers in this report. Three AFLP primer pairs generated a total of 357 and 226 markers for C. konishii and C. lanceolata samples, of which 56.1 and 65.3% are polymorphic, respectively. Analysis of molecular variance indicates a 4.78% variation between C. konishii and C. lanceolata. A relatively high value of genetic variation (24.60%) was apportioned between the populations of C. konishii. In contrast, a lower divergence value (12.21%) between populations was found for C. lanceolata. The population with the highest genetic diversity was found in Nantou County, which concurred with the results of many other tree species investigated in Taiwan. The estimates of the number of migrants between populations (Nm), obtained from population pair-wise PhiST, suggest that gene flow in C. konishii is efficient in some adjacent populations but is restricted in the rest. Individual UPGMA tree, generated based on AFLP markers, suggests six evolutionary lineages for C. konishii. All evolutionary lineages of C. konishii were derived from C. lanceolata. In conclusion, the migration patterns of Cunninghamia from mainland China may have been established following multiple sources, migrant-pools, long-distance dispersal events, and via different directions.

Asphaltene nanoparticle aggregation in mixtures of incompatible crude oils

We study the structure and phase behavior of asphaltenes comprised of large polyaromatic molecules in blends of naturally occurring crude oils using small angle neutron scattering (SANS). When two compatible oils are blended together, the asphaltenes remain dispersed as colloidal nanoparticles; however, when two incompatible oils are blended together, these asphaltene nanoparticles can aggregate to form microscale structures. We show that SANS directly probes asphaltene aggregation in unmodified (i.e., nondeuterated) crude oil mixtures due to a significant neutron scattering length density difference between the hydrogen-poor asphaltenes and the surrounding oil. Moreover, the small length scales probed by SANS are ideally suited for studying asphaltene aggregation: SANS simultaneously provides the average size and concentration of nanoscale asphaltene particles and also the volume fraction of microscale asphaltene aggregates. These discoveries yield a practical means for directly assessing the compatibility of crude oils and for diagnosing refinery fouling problems resulting from blending incompatible oils.

Thoracic empyema in children: early surgical intervention hastens recovery

The optimal management of thoracic empyema in children is still controversial. In this retrospective study, we analyze our six-year experience in the management of empyema. From April 1995 to December 2001, 39 patients under age 6 years were admitted with the diagnosis of empyema. These patients were assigned by the method of empyema management to one of two groups (either the conservatively treated or surgically treated group). The surgical patients were divided on the basis of the timing of surgical intervention into either the early (within 8 hospital days) or late (beyond 8 hospital days) surgical group. There was no difference in total hospital stay between those treated conservatively (24.3 +/- 11.6 days) and surgically (24.5 +/- 7.9 days). Among the surgically treated patients, recipients of early surgical intervention had significantly shorter hospital stay (20.2 +/- 5.9 days) than those receiving late surgical intervention (30.1 +/- 6.5 days). Early surgical intervention in cases of thoracic empyema in young children can shorten hospitalization. These children should undergo surgery if their clinical course does not improve within one week.

Increase of viability of entrapped cells of Lactobacillus delbrueckii ssp. bulgaricus in artificial sesame oil emulsions

A technique was developed to protect lactic acid bacteria (Lactobacillus delbrueckii ssp. bulgaricus) against simulated gastrointestinal conditions by encapsulation of bacterial cells within artificial sesame oil emulsions. Purified sesame oil bodies consisting of approximately 99% oil, 0.5% phospholipid, and 0.5% protein were decomposed by heating at 70 degrees C for 1 h. The bacteria cultured in nonfat milk were encapsulated in artificial oil emulsions constituted with decomposed sesame oil bodies and excess sesame or vegetable cooking oil. Viability of bacteria in storage at 4 degrees C for 16 d was substantially elevated from 0.023 to 5.45% after encapsulation. Compared with free cells, the entrapped bacteria demonstrated a significant increase (approximately 10(4) times) in survival rate when subjected to simulated high acid gastric or bile salt conditions. The results indicate that artificial sesame oil emulsion may serve as an effective biocapsule for encapsulation of bacteria in dairy products.

Immunohistochemical analysis of epidermal growth factor receptor family members in stage I non-small cell lung cancer

BACKGROUND

To elucidate the relationship between the expression of epidermal growth factor receptor family members (ErbB-1, neu/ErbB-2, ErbB-3, and ErbB-4) and tumor recurrence.

METHODS

We used immunohistochemistry to examine the expression of four epidermal growth factor receptor family members in 73 patients with stage I non-small cell lung cancer.

RESULTS

Using Cox univariate analysis, we determined that angiolymphatic tumor emboli and non-well-differentiated tumor cells were two significant conventional pathologic predictors of tumor recurrence, and that ErbB-1 and ErbB-3 were also significant predictors. Co-expression of ErbB-1+, -3+, or expression of three or more epidermal growth factor receptor family members had a significant effect on lung cancer recurrence. A stepwise multivariate Cox proportional hazards regression analysis provided a predictive model for tumor recurrence.

CONCLUSIONS

The present study shows that in patients with a non-well-differentiated tumor, overexpression of ErbB-3 is a useful marker for predicting tumor recurrence. The present study also confirmed that ErbB-1 expression increased in proportion to the loss of tumor differentiation. The correlation between ErbB-3 and distant metastasis was good.

Molecular characterization of Newcastle disease viruses isolated from recent outbreaks in Taiwan

A reverse transcription-polymerase chain reaction (RT-PCR) was described which amplified a portion of the F and HN genes of Newcastle disease virus (NDV) isolated from recent outbreaks in Taiwan. The F protein plays an important role in determining the virulence of NDV strains. Sequencing of a region specifying the F protein cleavage site was therefore undertaken and this verified the correlation between deduced amino sequences and pathogenicity. Analysis of the deduced amino acid sequences of the F protein cleavage site showed that all recent Taiwanese isolates in 1999 were velogenic viruses. All the virulent viruses have the amino acid sequence 112RRQKR116 for the C-terminus of the F2 protein and phenylanine (F) at the N-terminus of the F1 protein, residue 117. A phylogenetic tree based on the nucleotide sequences of the F gene revealed that recent Taiwanese NDV isolates responsible for recent outbreaks were classified into two distant genotypes (VI and VII). Genotype VI virus is the first finding in Taiwan and has a highly genetic similarity to European isolates, suggesting that they might have originated from a common ancestor.

Molecular characterisation of very virulent infectious bursal disease viruses in Taiwan

The very virulent infectious bursal disease virus (vv IBDV) RNA in the bursa of Fabricius and spleen from experimentally infected chickens or field samples was detected by in situ hybridisation (ISH) with subsequent reverse transcription (RT)-polymerase chain reaction (PCR) and sequence analysis. The VP 2 gene of vv IBDV was detected by ISH in infected chicken tissues with a cloned digoxigenin (DIG)-labelled cDNA probe. To verify ISH, RT - PCR was used to amplify two 643- and 500-base pair fragments on the VP 2 gene of IBDV in the bursa of Fabricius. With all isolates, two c DNA fragments of 643 and 500 bp long, respectively, were generated as expected and further confirmed the specificity of ISH. Analysis of the hypervariable region (HVR) of the VP 2 gene revealed that a serine-rich heptapeptide SWSASGS located at amino acids 326-332 was conserved in recent Taiwanese strains, and two amino acid substitutions were found in the classical Taiwanese strains at positions 330M and 331W. Three amino acids were unique to the vv strains at positions 222A, 256I and 294I, compared with classical and variant strains. Sequence and phylogenetic analysis showed that the recent Taiwanese strains were closely related, very similar to vv IBDV s from Europe, China, Japan, and Africa, and distantly related to the Taiwanese classical strains.

Attrition of bystander CD8 T cells during virus-induced T-cell and interferon responses

Experiments designed to distinguish virus-specific from non-virus-specific T cells showed that bystander T cells underwent apoptosis and substantial attrition in the wake of a strong T-cell response. Memory CD8 T cells (CD8(+) CD44(hi)) were most affected. During acute viral infection, transgenic T cells that were clearly defined as non-virus specific decreased in number and showed an increase in apoptosis. Also, use of lymphocytic choriomeningitis virus (LCMV) carrier mice, which lack LCMV-specific T cells, showed a significant decline in non-virus-specific memory CD8 T cells that correlated to an increase in apoptosis in response to the proliferation of adoptively transferred virus-specific T cells. Attrition of T cells early during infection correlated with the alpha/beta interferon (IFN-alpha/beta) peak, and the IFN inducer poly(I:C) caused apoptosis and attrition of CD8(+) CD44(hi) T cells in normal mice but not in IFN-alpha/beta receptor-deficient mice. Apoptotic attrition of bystander T cells may make room for the antigen-specific expansion of T cells during infection and may, in part, account for the loss of T-cell memory that occurs when the host undergoes subsequent infections.

Pathogenicity and drug susceptibility of the Pasteurella anatis isolated in chickens in Taiwan

A strain of Pasteurella anatis (PA) was isolated from the sinus of an adult leghorn laying chicken with sinusitis, nasal discharge, drop in egg production, and low mortality, symptoms initially thought to indicate infectious coryza. The tiny, smooth, whitish colonies were identified as PA. To compare its pathogenicity with that of commercial broilers, nine groups, 10 birds per group, of 10-day-old broilers were individually inoculated with the strain of PA, Pasteurella multocida (PM), or Escherichia coli (EC) by intravenous, intraperitoneal, intramuscular, or subcutaneous inoculation. The PA was determined to cause the signs, lesions, and septicemic death, which are similar to the symptoms of PM or EC infection. At 1 wk postinfection (PI), the mortality rate was between that of PM and EC infection at 1 wk PI. Twenty antimicrobial-containing discs were evaluated, and the isolate was highly sensitive to cetiofer, amoxicillin, lincopectin, and furazolidone. Furthermore, it was moderately sensitive to tetracycline and enrofloxacin and only slightly sensitive to cephalothin, chloramphenicol, flumequine, nalidixic acid, neomycin, oxolinic acid, streptomycin, and trimethoprim. The PA infection was treated successfully with amoxicillin.

Redoing reconstruction of the esophagus using remnants of the ileo-left colon aided by microvascular anastomosis

Theoretically, the jejunum, fasciocutaneous or myocutaneous flap is recommended as an esophageal substitute in redoing reconstruction of the esophagus after a second incidence of corrosive injury. However, other esophageal substitutes should also be considered. We present a case of a 42-year-old woman who underwent esophageal reconstruction using an ileocolon graft for corrosive esophageal stricture ten years before. The patient ingested caustic drain cleaner again and underwent resection of the ileocolon graft secondary to corrosive necrosis. Two and a half months after the second incidence of corrosive injury, reconstruction of the esophagus was again performed using a graft of remnant ileo-left colon aided by microvascular anastomosis. The patient was able to swallow a regular diet after the procedure. Remnant ileo-left colon is a good alternative esophageal substitute in cases of repeated corrosive injury.

Esophageal reconstruction for hypopharyngoesophageal strictures after corrosive injury

OBJECTIVE

To evaluate the surgical outcome of patients with caustic stricture of the hypopharyngoesophagus.

MATERIALS AND METHODS

During a 25-year period, we performed esophageal reconstruction in 152 patients with diffuse or multiple caustic esophageal stricture. Of them, esophageal substitute was pulled up and anastomosed to the hypopharynx in 50 (33%) patients, and anastomosed to the cervical esophagus in the other 102 (67%) patients. Patients whose esophageal substitute anastomosed to the hypopharynx were enrolled to the present study. Among these 50 study patients, 13 underwent ablation of damaged organs and feeding jejunostomy in acute stage of corrosive injury, and the remaining 37 patients were initially organ preserved with or without feeding gastrostomy or jejunostomy. Six patients had respiratory distress caused by laryngotracheal stricture. The ileocolon (28/50) was commonly used as an esophageal substitute in reconstruction and most substitutes (43/50) went through the substernal route.

RESULTS

There was one operative death. Eight (16%) patients had major early postoperative complications. Six patients underwent revision for late stenosis of hypopharyngeal anastomosis, and one redoing reconstruction using the jejunum because of failure of the transplanted ileocolon. Postoperatively, swallow function and maintaining body weight were considered good in 42 patients (84%) after an average of 8 months follow-up. Five of six patients who underwent concomitant tracheostomy or laryngosurgery for laryngotracheal stricture got unsatisfactory result. The surgical outcome of the study patients was worse than that in patients with esophageal substitute anastomosed to a healthy cervical esophagus. In the later group of patients, 95/102 (93%) had good swallow function and only 7/102 (6.8%) had major early complications.

CONCLUSION

Caustic stricture of the hypopharyngoesophagus is a challenging reconstructive problem. A successful reconstruction requires a correct hypopharyngeal opening and anastomosis, a good esophageal substitute, and a patent esophageal route and airway.

Ventilator-associated pneumonia with circuit changes every 2 days versus every week

BACKGROUND

Frequent ventilator circuit changes are expensive and sometimes unnecessary. Following the worldwide trend to lengthen the intervals for ventilator circuit change from 2 days to 1 week, this study aims to assure that low rate of ventilator-associated pneumonia (VAP) can be maintained with cost containment.

METHODS

Ventilator circuits were routinely changed every 7 days in the study period for 2 years and every 2 days during the historical control period of another 2 years. Pediatric patients (age less than 15 years) were not included. Nosocomial pneumonia was diagnosed by the criteria of the Centers of Disease Control and Prevention (CDC) of the United States (US). VAP was identified by combining and comparing 2 databases from the Respiratory Therapy Department and the Infection Control Unit of our hospital.

RESULTS

In the study group, 225 episodes of pneumonias were observed in 7,068 patients and 87,338 ventilator days. The rate of VAP was 2.58 per 1,000 ventilator days. There were 174 episodes of pneumonia in 6,213 patients and 65,467 ventilator days of the control group. The rate of VAP was 2.66 per 1,000 ventilator days. The difference between both groups was not significant (p = 0.803). Yet, the cost curbed was around 80,000 US dollars per year.

CONCLUSIONS

Extending ventilator circuit change interval from 2 days to 7 days do not increase the risk for VAP, but the cost savings for labor and supply are substantial.

Surgery for lung abscess in immunocompetent and immunocompromised children

PURPOSE

The aim of this study was to evaluate the surgical management results of lung abscess in immunocompetent and immunocompromised children.

METHODS

Surgery was performed on 30 children with lung abscess or necrotizing pneumonia refractory to medical treatment in a 12-year period. Of them, 23 were immunocompetent, and 7 were immunocompromised. Pulmonary resection was performed including unilateral lung in 28, bilateral in 2, and 2 lobes in 6. Concomitant decortication was performed in 18 (78.2%) immunocompetent patients.

RESULTS

Increased incidence of surgery for lung abscess was caused mainly by drug-resistant and fungal infection. Surgery was performed commonly for bacterial lung abscess on patients less than 5 years old and fungal lung abscess on adolescence. A multiple small abscess was the predominant type of abscess in immunocompetent patients, whereas 2-lobe involvement tended to occur in immunocompromised patients. Fungal lung abscess tended to occur on left lung and in female patients. Left lower lobe was involved most commonly in both groups of patients in which majority need lobectomy. Immunocompromised patients required a more extensive pulmonary resection. There were 3 postoperative complications (morbidity of 10.2%) with no postoperative mortality. Length of postoperative hospital stay ranged from 6 to 85 days with average of 18.4 days.

CONCLUSIONS

The incidence and pattern of lung abscess that required surgery between immunocompetent and immunocompromised children were different. A more aggressive, extensive surgical procedure is preferable for immunocompromised patients, and the surgical results were comparatively excellent to immunocompetent patients. However, the prognosis of immunocompromised children depends on their underlying disease process.

Fetal thymi from diabetes-prone but not diabetes-resistant BB/Wor rats fail to generate mature ART2+ T-cells in organ culture

Diabetes-prone (BBDP) BB rats develop spontaneous autoimmune diabetes mellitus. They are lymphopenic and severely deficient in ART2+ T-cells. Diabetes-resistant BB (BBDR) rats do not develop spontaneous diabetes and have normal numbers of ART2+ T-cells. T-cell lymphopenia in BBDP rats results from hematopoietic stem cell defects leading to abnormal intrathymic T-cell maturation. To study this process, we established rat fetal thymic organ cultures (FTOC). Like mouse FTOC, cultures of BBDR rat thymi yielded approximately 10(5) cells per lobe. The majority of cells were CD8+ART2+ T-cells. In contrast, BBDP rat FTOC yielded 60% fewer cells (approximately 0.3 x 10(5)/lobe), a smaller percentage of CD8+ and TcRalphabeta+ T-cells, and almost no detectable ART2+ T-cells. ART2 mRNA was detectable in BBDR but not BBDP FTOC. In contrast, expression of mRNAs encoding bcl-2 and a panel of cytokines was comparable in BBDP and BBDR FTOC. Addition of anti-ICAM-1 (CD54) antibody reduced T-cell number in BBDR rat FTOC by approximately 70%, but addition of IL-7 or IL-1beta had no effect. The data demonstrate that BBDP thymocytes fail to generate mature ART2+ T-cells in rat FTOC, a system that can now be used to study the mechanism of this process.

Cutting edge: two distinct mechanisms lead to impaired T cell homeostasis in Janus kinase 3- and CTLA-4-deficient mice

Cytokine receptor signaling and costimulatory receptor signaling play distinct roles in T cell activation. Nonetheless, deficiencies in either of these pathways lead to seemingly similar phenotypes of impaired T cell homeostasis. A dramatic expansion of CD4(+) peripheral T cells with an activated phenotype has been observed in both Janus kinase (Jak) 3-deficient and CTLA-4-deficient mice. Despite these similarities, the mechanisms driving T cell expansion may be distinct. To address this possibility, we examined the TCR repertoire of peripheral T cells in Jak3(-/-) and CTLA-4(-/-) mice using complementarity-determining region 3 spectratype analysis. Interestingly, a restricted and highly biased TCR repertoire was observed in the Jak3(-/-) T cells, strongly supporting a role for foreign Ag in the activation and expansion of these cells. In contrast, CTLA-4(-/-) T cells had a diverse and unbiased TCR repertoire, suggestive of a universal, Ag-independent mechanism of activation and expansion. These findings provide insight into the diverse mechanisms controlling T cell homeostasis.

Intrathoracic muscle flap transposition in the treatment of fibrocavernous tuberculosis

BACKGROUND AND OBJECTIVE

Conventionally, pulmonary resection with thoracoplasty is used to treat fibrocavernous complication of pulmonary tuberculosis. This operation is usually bloody, time-consuming with complicated postoperative course. To prevent massive blood loss and preserved pulmonary function, a more simplified operative procedure, cavernostomy combined intrathoracic muscle flap transposition was used and the outcome was evaluated in this study.

DESIGN

Retrospective review.

METHODOLOGY

Between December 1989 and June 1996, a total of ten patients with fibrocavernous pulmonary tuberculosis were managed using cavernostomy combined with intrathoracic muscle flap transposition. Five of them had concomitant aspergilloma within the cavity while three had multiple drug resistant pulmonary tuberculosis. The muscle flap was used to plombage the cavity and reinforce the closure of bronchopleural fistula after cavernostomy.

RESULTS

Six postoperative complications occurred in five patients, including reformation of cavity (2), bronchopleurocutaneous fistulae (3), and postoperative bleeding (1). The success or failure of intrathoracic muscle flap transposition on patients with fibrocavernous tuberculosis was significantly correlated with the size of the cavity (194.0+/-11.2 vs. 283.0+/-44.6 cm(3), P=0.016) and the number of bronchopleural fistulae (1.6+/-0.4 vs. 4.0+/-0.4, P=0.008). There was no operative death and in long term follow-up, there was no recurrence of hemoptysis or deterioration of pulmonary function in the successful group of patients.

CONCLUSIONS

Cavernostomy combined with intrathoracic muscle flap transposition can be used to treat well-selected fibrocavernous pulmonary tuberculosis patients, except on patients with large size cavity, multiple bronchopleural fistulae or multiple drug resistance tuberculosis.

The virus-specific and allospecific cytotoxic T-lymphocyte response to lymphocytic choriomeningitis virus is modified in a subpopulation of CD8(+) T cells coexpressing the inhibitory major histocompatibility complex class I receptor Ly49G2

The role of negatively signaling NK cell receptors of the Ly49 family on the specificity of the acute CD8(+) cytotoxic T-lymphocyte (CTL) response was investigated in lymphocytic choriomeningitis virus (LCMV)-infected C57BL/6 mice. Activated CD8(+) T cells coexpressing Ly49G2 expanded during LCMV infection, and T-cell receptor analyses by flow cytometry and CDR3 spectratyping revealed a unique polyclonal T-cell population in the Ly49G2(+) fraction. These cells lysed syngeneic targets infected with LCMV or coated with two of three LCMV immunodominant peptides examined. Transfection of these sensitive targets with H2D(d), a ligand for Ly49G2, inhibited lysis. This was reversed by antibody to Ly49G2, indicating effective negative signaling. LCMV characteristically induces an anti-H2(d) allospecific T-cell response that includes T-cell clones cross-reactive between allogeneic and LCMV-infected syngeneic targets. The CD8(+) Ly49G2(+) population mediated no allospecific killing, nor was any NK-like killing observed against YAC-1 cells. This study shows that CD8(+) Ly49G2(+) cells participate in the virus-induced CTL response but lyse a more restricted range of targets than the rest of the virus-induced CTL population.

Antioxidative effect of intestinal bacteria Bifidobacterium longum ATCC 15708 and Lactobacillus acidophilus ATCC 4356

The antioxidative effect of intact cells and intracellular cell-free extracts of intestinal lactic acid bacteria B. longum (ATCC 15708) and L. acidophilus (ATCC 4356) was investigated. Both intact cells and intracellular cell-free extracts of 10(9)cells of B. longum and L. acidophilus demonstrated antioxidative activity, inhibiting linoleic acid peroxidation by 28-48%. This indicated that these two strains demonstrated excellent antioxidative activity. B. longum and L. acidophilus also showed the ability to scavenge alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) free radical, scavenging 21-52%. The intact cells of these two intestinal bacteria demonstrated a high inhibitory effect on the cytotoxicity of 4-nitroquinoline-N-oxide (4NQO). Cytotoxicity of 4NQO was reduced by L. acidophilus by approximately half and by almost 90% by B. longum. Nevertheless, no inhibition of cytoxicity observed for intracellular cell-free extracts of 10(9) cells of B. longum and L. acidophilus. The effect of B. longum and L. acidophilus on inhibiting plasma lipid peroxidation was also evaluated. The results showed that both intestinal strains were able to protect plasma lipid from oxidation at different degrees. The inhibition rates on plasma lipid peroxidation ranged from 11 to 29% for 10(9) cells of B. longum and L. acidophilus. Generally speaking, B. longum demonstrated better antioxidative ability than L. acidophilus in this study.

Evolution of the CD8 T-cell repertoire during infections

CD8 T cells exist in a dynamic network whose repertoire remains static in the absence of infection but changes in the presence of foreign antigens. Individuals each have unique T-cell repertoires that continually evolve in the presence of antigen and of cross-reactive heterologous antigens, and homeostatic forces drive deletions in T-cell memory pools to accommodate the entry of new memory cells into a finite immune system.