Histological improvement of long-term antiviral therapy in chronic hepatitis B patients with persistently normal alanine aminotransferase levels

The aim of this study was to evaluate the histological outcomes of chronic hepatitis B (CHB) patients with persistently normal alanine aminotransferase (ALT) levels after long-term antiviral therapy. Paired liver biopsies before and after lamivudine (LAM) treatment in CHB patients with normal and elevated ALT levels were compared. Histological response was defined as a 1-point decrease according to the Scheuer scoring system, without worsening of fibrosis between pretreatment and posttreatment biopsies. Among the 48 patients who underwent paired liver biopsies, 17 had persistently normal baseline ALT level and 31 had elevated ALT level. The median age of the patients was 44 years and 72.9% of the patients were male. The median duration of antiviral treatment was 44.5 months (range 14-104). Long-term follow-up of liver biopsies revealed that 82.4% of patients in the normal ALT group and 61.3% in the elevated ALT group had a baseline fibrosis score of 4, which was reduced to 17.6% and 38.7% after long-term therapy, respectively, indicating reversal of cirrhosis in a large proportion of both groups, especially in patients with normal baseline ALT levels. Long-term antiviral treatment could achieve significant histological improvement in CHB patients with fibrosis or cirrhosis, regardless of ALT level.

Evaluation of the GenoType® MTBDRplus assay and identification of a rare mutation for improving MDR-TB detection

OBJECTIVE

To assess the new GenoType® MTBDRplus assay for the rapid detection of multidrug-resistant tuberculosis (MDR-TB) in comparison with DNA sequencing to identify drug resistance mutation profiles in China.

DESIGN

Using MTBDRplus, drug susceptibility testing (DST) and DNA sequencing, 237 Mycobacterium tuberculosis strains were tested.

RESULTS

The sensitivity of MTBDRplus was 75.0% (126/168) for isoniazid (INH) resistant strains, and 93.5% (157/168) for rifampicin (RMP) resistant strains. It correlated well with sequencing, with 94.9% and 99.6% agreement for each strain category and 100% specificity for all categories. The two most common rpoB mutations were S531L (53.6%, 90/168) and D516G (17.3%, 29/168) in RMP-resistant strains. INH resistance was dominated by the katG 315 locus (S to T, N, R, I) mutation (73.7%, 124/168), and a rare katG mutation, S315N (6.5%, 11/168), not covered by MTBDRplus was identified. The mutation combination inhA-15/inhA-8 and katG315 (34 strains) was characteristically displayed in MDR-TB strains (23.5%), but not in INH-monoresistant strains.

CONCLUSIONS

Although Genotype MTBDRplus is a rapid and reliable molecular test for detecting MDR-TB, a significant proportion of strains in China contain a rare katG S315N mutation that would be missed by the assay. Further improvements may be achieved by incorporating this mutation into the assay to increase sensitivity in detecting INH resistance in China.

EGFR tyrosine kinase mutation testing in the treatment of non-small-cell lung cancer

BACKGROUND

Non-small-cell lung cancer (nsclc) tumours with activating mutations of the epidermal growth factor receptor (efgr) tyrosine kinase are highly sensitized to the effects of oral tyrosine kinase inhibitors such as gefitinib and erlotinib, suggesting the possibility of targeted treatment of nsclc based on EFGR mutation status. However, no standardized method exists for assessing the EGFR mutation status of tumours. Also, it is not known if available methods are feasible for routine screening. To address that question, we conducted a validation study of methods used for detecting EGFR mutations in exons 19 and 21 at molecular laboratories located in five specialized Canadian cancer centres.

METHODS

The screening methods were first optimized using cell lines harbouring the mutations in question. A validation phase using anonymized patient samples followed.

RESULTS

The methods used at the sites were highly specific and sensitive in detecting both mutations in cell-line dna (specificity of 100% and sensitivity of at least 1% across all centres). In the validation phase, we observed excellent concordance between the laboratories for detecting mutations in the patient samples. Concordant results were obtained in 26 of 30 samples (approximately 87%). In general, the samples for which results were discordant were also less optimal, containing small amounts of tumour.

CONCLUSIONS

Our results suggest that currently available methods are capable of reliably detecting exon 19 and exon 21 mutations of EFGR in tumour samples (provided that sufficient tumour material is available) and that routine screening for those mutations is feasible in clinical practice.

Ex vivo expansion of natural killer cells with high cytotoxicity by K562 cells modified to co-express major histocompatibility complex class I chain-related protein A, 4-1BB ligand, and interleukin-15

A large number of natural killer (NK) cells with high function are expected to generate especially in tumor adoptive immunotherapy. Here K562 cells were genetically modified to co-express major histocompatibility complex class I chain-related protein A (MICA), 4-1BB ligand, and IL-15, called K562-MICA-4-1BBL-IL-15. The modified K562 cells not only promoted activation, proliferation, and survival of NK cells, but also enhanced NK cell cytotoxicity. In long-term culture tests, K562-MICA-4-1BBL-IL-15 cells stimulated NK cell to expand mean 550 folds in 24-day culture and to cover from 14.8% of total peripheral blood monoclonal lymphocytes on day 1 to 86.7% on day 24. Prevalent NK cells after expansion enhanced the ability of killing targets and producing interferon gamma (IFN-γ), and kept high expression of activating receptors. The results indicated that K562-MICA-4-1BBL-IL-15 cells would be developed for expansion of NK cells ex vivo and may have important implications for clinical immunotherapy.

Verbal memory retrieval engages visual cortex in musicians

As one major line of research on brain plasticity, many imaging studies have been conducted to identify the functional and structural reorganization associated with musical expertise. Based on previous behavioral research, the present study used functional magnetic resonance imaging to identify the neural correlates of superior verbal memory performance in musicians. Participants with and without musical training performed a verbal memory task to first encode a list of words auditorily delivered and then silently recall as many words as possible. They performed in separate blocks a control task involving pure tone pitch judgment. Post-scan recognition test showed better memory performance in musicians than non-musicians. During memory retrieval, the musicians showed significantly greater activations in bilateral though left-lateralized visual cortex relative to the pitch judgment baseline. In comparison, no such visual cortical activations were found in the non-musicians. No group differences were observed during the encoding stage. The results echo a previous report of visual cortical activation during verbal memory retrieval in the absence of any visual sensory stimulation in the blind population, who are also known to possess superior verbal memory. It is suggested that the visual cortex can be recruited to serve as extra memory resources and contributes to the superior verbal memory in special situations. While in the blind population, such cross-modal functional reorganization may be induced by sensory deprivation; in the musicians it may be induced by the long-term and demanding nature of musical training to use as much available neural resources as possible.

ERCC1 polymorphism in patients with locally advanced head and neck squamous cell carcinoma treated with concomitant chemoradiation: Prevalence and impact on treatment efficacy

6032

Background: Excision repair cross-complementation group 1 (ERCC1) is a gene coding for the nucleotide excision repair complex. Its increased expression and polymorphism at codon 118 have been linked to poor response to chemotherapy or chemoradiation in several types of cancer. ERCC1 removes the cisplatin adducts on the DNA of cells and its polymorphism appears to be a marker of chemotherapeutic resistance to platinum-based therapy. Objectives: To determine the prevalence of the polymorphism of ERCC1 (codon 118) in patients with locally advanced HNSCC treated with concomitant platinum-based chemoradiation therapy with or without prior surgery, and its effect on eficacy evaluated by locoregional control, disease-free survival and overall survival. Methods: Prospective data on efficacy was available on 460 consecutive patients treated with concomitant chemoradiation in our institution with a minimal follow-up of 2 years. Of these, 230 fixed and paraffin embedded biopsies or surgical specimens were collected. DNA was extracted from specimens and polymorphism of codon 118 was determined using a PCR technique. All analysis were performed using Kaplan-Meier survival curves, Fisher's test for categorical data and log-rank statistics for failure times. Results: DNA extraction was successful in 222 patients. Polymorphism mapping was possible in 178 specimens. Genotypic distribution in the population was the following : AAT/AAT:40% (Gr1), AAC/AAT: 48%(Gr2), AAC/AAC: 12% (Gr3). At 3 years, evaluation of efficacy for Gr1, Gr2, and Gr3 was determined. Locoregional control was respectively 77%, 83%, and 67% (p = NS), DFS was 58%, 68% and 55% (p=NS), and OS was 70%, 69%, and 70% (p = NS). Conclusions: ERCC1 polymorphism did not have an impact in our population on response to chemoradiation therapy. It can be postulated that ERCC1 does not seem to discriminate patients for whom another treatment option should be sought for patients with locally advanced SCCHN. Further data will be presented at the meeting including a multivariate analysis using different markers tested in our laboratory (KRAS, MGMT methylation, etc).

No significant financial relationships to disclose.

[Dynamic changes in the expression of type VI collagen in mice with schistosomal liver fibrosis]

AIM

To clarify the dynamic changes in type VI procollagen mRNA expression and collagen content in mice with schistosomal liver fibrosis.

METHODS

Northern blot hybridization and immunohistochemical technique.

RESULTS

The expression of alpha 1(VI) procollagen mRNA measured by Northern blot hybridization in the liver of schistosome infected mice was elevated significantly at 8 wk post infection, peaked at 10 wk pi, slightly decreased at 12-16 wk pi, and sustained at high levels until 20 wk pi. Immunohistochemical assay revealed that the staining pattern of type VI collagen first appeared in the walls of central veins and liver sinusoids at 8 wk pi, then extended gradually to the egg granuloma and the portal tract, within and surrounding the egg granuloma to form dense reticular septum at the 12, 16 and 20 wk pi, respectively. The VI collagen content as indicated by the intensity of stain peaked at 16 wk pi.

CONCLUSION

Both the expression of alpha 1(VI) procollagen and the content of collagen VI were significantly increased in the liver of mice with early schistosomal fibrosis, suggesting that the type VI collagen detection might be of importance for evaluating the intensity of schistosomal liver fibrosis.

Use of body mass index to identify obesity-related metabolic disorders in the Chinese population

OBJECTIVE

To identify the body mass index (BMI; in kg/m2) cutoff that predicts the risk for obesity-related metabolic disorders for the Chinese population.

DESIGN

Community-based cross-sectional survey.

SETTING

Rural regions of Jiangxi and Anhui provinces and an urban community of Jing'an District of Shanghai, China.

SUBJECTS

Five hundred and twenty-nine non-pregnant, non-lactating urban and rural adults, aged 20-64 years without diagnosed diabetes.

RESULTS

Subjects were divided into two groups: with or without obesity-related metabolic disorders, which was defined as having at least one of the following: hypertension, insulin resistance, high plasma triacylglycerol, low-density lipoprotein-cholesterol or glucose. Gender-specific multiple logistic regression analysis demonstrated a significant dose-response relationship between BMI and obesity-related metabolic disorders, after adjusting for potential confounders. The lowest BMI interval associated with significant risk for both men and women (odds ratios of 2.67 and 3.46, respectively) was that of 22.5-24.4. Receiver-operating characteristic (ROC) curve analysis indicated that a BMI cutoff of 23 had the best combination of sensitivity and specificity and the shortest distance in the ROC curve, with positive and negative predictive values of 0.6-0.7 in both genders.

CONCLUSIONS

A BMI cutoff of 23 might be appropriate for use in identification of high risk of obesity-related metabolic disorders and serve as a public health action threshold in the Chinese population.

SPONSORSHIP

Center of a Livable Future, John Hopkins Bloomberg School of Public Health.

High-resolution crystals and preliminary X-ray diffraction studies of a catalytic RNA

High-resolution single crystals of a catalytic RNA molecule derived from the sequence of the satellite RNA of tobacco ringspot virus have been obtained. The unit-cell volumes of the RNA crystals vary depending on the crystallization conditions and temperature. The best crystal form, when flash frozen, has space group P1 with unit-cell dimensions a = 53.08, b = 71.81, c = 28.03 A, alpha = 98.43, beta = 104.32 and gamma = 74.54 degrees. This form diffracts to a resolution of 2.4 A. A heavy-atom derivative search is in progress.

[Experimental study on detection of Schistosoma japonicum 5D gene by using PCR]

AIM

To search for an effective method to diagnose the schistosomiasis and evaluate the effect of treatment.

METHODS

A PCR protocol was designed to detect the Schistosoma japonicum 5D gene encoding an immunogenic miracidial antigen in cercariae, eggs and adult worms.

RESULTS

Specific amplification of a 262 bp DNA fragment was achieved by using PCR and a 165 bp DNA fragment by using nest-PCR in cercariae, adult worms and eggs of Schistosoma japonicum. After 40 cycles by PCR, the product could be detected by agarose gel electrophoresis. This PCR protocol was able to detect as few as a single cercariae, a single egg or a pinpoint-sized tissue of adult S. japonicum. Nest-PCR and oligonucleotide probe hybridization could further increase the sensitivity. No specific PCR product was obtained with DNA from human leucocyte, Escherichia coli, Bacillus proteus vulgaris, Streptococcus faecalis and Salmonella typhi.

CONCLUSION

The sensitivity and specificity of this PCR protocol are satisfactory.

The pathogenicity of human immunodeficiency virus (HIV) type 1 Nef in CD4C/HIV transgenic mice is abolished by mutation of its SH3-binding domain, and disease development is delayed in the absence of Hck

The human immunodeficiency virus type 1 (HIV-1) Nef protein is an important determinant of AIDS pathogenesis. We have previously reported that HIV-1 Nef is responsible for the induction of a severe AIDS-like disease in CD4C/HIV transgenic (Tg) mice. To understand the molecular mechanisms of this Nef-induced disease, we generated Tg mice expressing a mutated Nef protein in which the SH3 ligand-binding domain (P(72)XXP(75)XXP(78)) was mutated to A(72)XXA(75)XXQ(78). This mutation completely abolished the pathogenic potential of Nef, although a partial downregulation of the CD4 cell surface expression was still observed in these Tg mice. We also studied whether Hck, one of the effectors previously found to bind to this PXXP motif of Nef, was involved in disease development. Breeding of Tg mice expressing wild-type Nef on an hck(-/-) (knockout) background did not abolish any of the pathological phenotypes. However, the latency of disease development was prolonged. These data indicate that an intact PXXP domain is essential for inducing an AIDS-like disease in CD4C/HIV Tg mice and suggest that interaction of a cellular effector(s) with this domain is required for the induction of this multiorgan disease. Our findings indicate that Hck is an important, but not an essential, effector of Nef and suggest that another factor(s), yet to be identified, may be more critical for disease development.

[Further study on cyclin D1 expression and function in human nasopharyngeal carcinoma cell line]

OBJECTIVE

In the present study, we tried to further elucidate the expression and function of cyclin D1 in human nasopharyngeal carcinoma (NPC) cell line.

METHODS

Western blot was used in the analysis of D-type cyclin expression profile. The distribution of this protein was determined in the double parameter flow cytometry (FCM). The function of cyclin D1 in nasopharyngeal carcinoma cell line was determined in the antisense-oligonucleotied-cyclin D1 and antibody mediated knock-out experiments.

RESULTS

The immunoblot analysis of two NPC cell lines showed that the spectra of D-type in NPC cell lines founded their expressions in D1, D2, and D3. It also suggested that the overexpression of cyclin D1 could lead to deregulation of G1/S control. An additional double parameter FCM showed a characteristic variation in HNE1 which was consistent with the cell-cycle oscillation and the peak level expressed in G0/G1 phase and the lowest level in the S-phase. Two experimental approaches aimed at specific functional knock-out of cyclin D1 were employed; the cyclin D1-ASPODN experiment showed an inhibition of cyclin D1 expression at mRNA level and a down-regulated cyclin D1 partial inhibition of progression into S phase, resulting in cell growth arrest while the electroporation of neutralizing antibodies demonstrated a specific delay of S-phase entry in HNE1 and the requirement for the cyclin D1 in cell cycle progression of HNE1 cell line in regulation of G1/S.

CONCLUSION

These data reveal that the cell-cycle regulatory function of cyclin D1 is essential for cell cycle progression in the G1 of nasopharyngeal carcinoma cell line and suggest that cyclin D1 play an important role in NPC carcinogenesis.

The AIDS disease of CD4C/HIV transgenic mice shows impaired germinal centers and autoantibodies and develops in the absence of IFN-gamma and IL-6

The mechanisms responsible for degeneration of germinal centers (GC) and follicular dendritic cell (FDC) networks during progression to AIDS remain elusive. Here, we show that CD4(+) T cells from CD4C/HIV-1 Tg mice, which develop a severe AIDS-like disease, express low levels of CD40 ligand. Accordingly, GC formation, FDC networks, and immunoglobulin isotype switching are impaired in these animals. However, Tg B cells respond to in vitro CD40 stimulation. Total serum IgG levels are reduced in Tg mice, whereas total IgM levels are increased with a significant amount showing DNA specificity. IFN-gamma- and IL-6-deficient CD4C/HIV Tg mice also develop the AIDS-like disease and produce auto-Ab. Thus, CD4C/HIV Tg mice have immune dysfunction accompanied by autoimmune responses.

Efficacy of continuous tracheal gas insufflation in spontaneously breathing canine with acute lung injury

OBJECTIVE

To investigate the effects of continuous tracheal gas insufflation (CTGI) combined with biphasic intermittent positive airway pressure (BIPAP) ventilation on dogs with spontaneous breathing.

METHODS

Eight canine models with oleic acid induced lung injury and spontaneous breathing were ventilated in a random order by Evita 2 (Drager Inc., Germany) in modes of BIPAP (BIPAP group) and BIPAP with CTGI flow rate of 3, 6 and 9 L/min (T3, T6 and T9 groups), respectively. The setting parameters of BIPAP were fiction of inspired oxygen 60%, inspiratory to expiratory ratio 1:1, respiratory rate 20 and positive end expiratory pressure 5 cm H2O. Arterial and mixed venous blood gas, lung mechanics, systemic and pulmonary hemodynamics status were monitored at the same level of PaCO2 obtained by adjusting peak inspiratory pressure of BIPAP.

RESULTS

Peak inspiratory pressure in the T6 group (14 +/- 4 cm H2O) and in the T9 group (11 +/- 3 cm H2O) were significantly lower than that of BIPAP (20 +/- 5 cm H2O, P < 0.01), but there was no significant difference among the T3, T6 and T9 groups or between the T3 and BIPAP groups. PaO2, mean artery blood pressure, mean pulmonary artery pressure, pulmonary artery wedge pressure, cardiac output, oxygen delivery and oxygen consumption all remained unchanged in four different conditions.

CONCLUSIONS

Using BIPAP combined with CTGI does not cause asynchrony between ventilator and spontaneous breathing, but significantly decreases airway pressure with no influence on hemodynamics and oxygenation. Therefore, BIPAP with CTGI may be a useful support technique, especially in cases where the airway pressure should be limited.

[The effects of extrinsic positive end-expiratory pressure on work of breathing in patients with chronic obstructive pulmonary disease]

OBJECTIVE

To study the effect of extrinsic positive end-expiratory pressure(PEEPe) on work of breathing in chronic obstructive pulmonary disease (COPD) patients and its mechanism.

METHODS

10 ventilated patients [4 males and 6 females with mean age of (70.1 +/- 5.5) years] with exacerbation of COPD were admitted into the study. All the patients' cardiopulmonary functions were stable, and they could receive pressure support ventilation (PSV). Patients with sever heart dysfunction, hepatic dysfunction, renal dysfunction or fever were ruled out. Each patient had an esophagus balloon pressure sensor inserted, and the esophagus balloon was properly positioned using "occlusion test". Flow sensor was placed at the end of tracheal tube opening. Then esophagus balloon pressure sensor and flow sensor were connected with Bicore CP-100 pulmonary monitor. Dynamic intrinsic positive end-expiratory pressure (PEEPi, dyn), difference of esophagus pressure (dPes), work of breathing patient (WOBp), work of breathing ventilator (WOBv), pressure time product (PTP), tidal volume (Vt), respiratory rate (RR), minute ventilation (MV), peak inspiratory flow rate (PIFR), peak expiratory flow rate (PEFR), expiratory airway resistance (Rawe), fraction of inspiration (Ti/Ttot) and so on were measured. PEEPi,dyn was measured by esophagus balloon technique. Electrocardiogram and noninvasive blood pressure modes were added to HP M1165A monitor. Heart rate (HR) and blood pressure (BP) were also measured. Arterial blood was analyzed to measure pH, partial pressure of oxygen in arterial blood (PaO(2)), partial pressure of carbon dioxide in arterial blood (PaCO(2)) and saturation of arterial blood oxygen (SaO(2)). At first, PEEPi, dyn was measured when PEEPe was zero, which was called PEEPi, dynz and was set as baseline. Then PEEPe was set randomly, which was 0%, 40%, 60%, 80% and 100% of PEEPi, dynz respectively. Other parameters remained stable. All the indexes were measured 30 minutes after the level of PEEPe was changed.

RESULTS

WOBp decreased as PEEPe increased, from (1.08 +/- 0.49) J/L of PEEPe-0% of PEEPi,dynz to (0.57 +/- 0.32) J/L of PEEPe-100% of PEEPi, dynz, and significant difference was found between each level of PEEPe and the baseline (P < 0.01). But we didn't find significant difference between PEEPe-80% of PEEPi,dynz and PEEPe-100% of PEEPi, dynz. WOBv increased significantly as PEEPe increased, from (1.50 +/- 0.47) J/L of PEEPe-0% of PEEPi, dynz to (1.82 +/- 0.56) J/L of PEEPe-80% of PEEPi, dynz and (1.85 +/- 0.48) J/L of PEEPe-100% of PEEPi,dynz(P < 0.01). The total WOB (WOBp + WOBv) remained steady. PTP trended to decrease, from (153.6 +/- 76.8) cm H(2)O x s x m(-1) of PEEPe-0% of PEEPi, dynz to (86.9 +/- 45.9) cm H(2)O x s x m(-1) of PEEPe-100% of PEEPi, dynz; the difference of PTP between PEEPe-40% of PEEPi,dynz and PEEPe-0% of PEEPi, dynz was significant(P < 0.05), the differences between other levels of PEEPe and PEEPe-0% of PEEPi, dynz were very significant (P < 0.01), but no significant difference was found between PEEPe-80% of PEEPi, dynz and PEEPe-100% of PEEPi, dynz. PEEPi,dyn also decreased significantly as PEEPe increased, from (7.70 +/- 1.42) cm H(2)O of PEEPe-0% of PEEPi, dynz to (2.10 +/- 0.57) cm H(2)O of PEEPe-100% of PEEPi, dynz, very significant differences were found between each level of PEEPe and the baseline (P < 0.01). Significant positive linear correlation was found between DeltaWOBp and DeltaPEEPi, dyn were(r = 0.609, P < 0.01, n = 10). dPes decreased as PEEPe increased, from (15.20 +/- 4.16) cm H(2)O of PEEPe-0% of PEEPi, dynz to (8.20 +/- 4.13) cm H(2)O of PEEPe-100% of PEEPi, dynz, and very significant differences were found between each level of PEEPe and the baseline (P < 0.01). But the difference between PEEPe-80% of PEEPi, dynz and PEEPe-100% of PEEPi, dynz wasn't significant, even dPes of PEEPe-100% of PEEPi, dynz was higher than that of PEEPe-80% of PEEPi, dynz. Vt didn't change markedly. RR, MV and f/Vt increased slightly. Both PIFR and PEFR didn't change markedly. At the same time, HR, BP and blood gas analysis were investigated, but no significant change was found.

CONCLUSION

PEEPe can reduce WOBp significantly and improve the coordination between the patient and ventilator. It is shown that decrement of pressure difference between alveolar and central airway leads to decrement of WOBp.

Three-dimensional correction of scoliosis using TSRH instrumentation

OBJECTIVE

To evaluate the results of TSRH instrumentation in the correction of coronal, sagittal and rotational deformity of scoliosis.

METHODS

From January 1998 to December 1999, thirty-two consecutive patients (6 males, 26 females)with scoliosis underwent anterior or posterior spinal instrumentation and fusion using TSRH instrumentation. Of these cases, 21 were idiopathic scoliosis and 11 were congenital scoliosis. The average age at surgery was 16.4 years (range, 11 approximately 45 years). The mean Cobb angle at surgery was 71.2 degrees range, 44 degrees approximately 125 degrees) in the coronal plane, and 49. degrees range, 16 degrees aprroximately 67degrees in the sagittal plane. Rotational deformity (Nash-Moe) ranged from I to III degree. Preoperative apical translation averaged 4.8 cm (range, 3 approximately 9 cm).

RESULTS

The average follow-up duration was 13.3 months (range, 10 approximately 24 months). At the final follow-up, the mean Cobb angle in the coronal plane was 26.6 (range, 10 degrees approximately 73 degrees), with a 63.8% of improvement. Sagittal alignment was well maintained with a mean Cobb angle of 28 degrees (range, 10 degrees approximatelky 45 degrees). The average correction of rotation of the apical vertebra was I degree. The average apical translation was 1.6 cm (range, 0.5 approximately 5.0 cm) representing a correction rate of 66, 7%. Complication was noted in two cases with an incidence of 3.1%, one case had superficial infection and the other one had lower hook dislocation. There was no neurologic deficit and pseudoarthrodesis in this series.

CONCLUSION

TSRH instrumentation is an effective and convenient three-dimensional correction system with a lower rate of complication, which can not only correct the coronal and rotational deformity, but maintain the sagittal alignment as well.

[Detection of telomerase activity and its clinical significance in colonic cancers by PCR-ELISA]

Using the recently developed telomerase PCR-ELISA detection kit, the authors detected the telomerase activity in 12 paired colonic cancer biopsies. It was found that strong telomerase activity was detected in all of the 12 colonic cancer tissues but not in adjacent non-cancerous tissues. These results suggest that the detection of telomerase activity by the PCR-ELISA assay could be used as a supplementary means for the diagnosis of colonic cancer.

[A study on the pathogenesis of Streptococcus mitis exotoxin]

OBJECTIVE

To study the isolation, purification and pathogenesis of Streptococcus mitis pyrogenic exotoxin causing toxic shock syndrome.

METHODS

Streptococcus mitis isolated from patients' throat were shaking cultivated. After being centrifuged, the supernatant fluid of the culture was precipitated with 20%, 40%, 60%, 80% (NH(4))(2)SO(4) respectively and the fast protein liquid chromatography(FPLC) was used for the final step of purification. Rabbits receiving subcutaneous injection with respective purified proteins were monitored daily for fever. The ability of the purified proteins to enhance the susceptibility of the rabbits to lethal Escherichia coli endotoxin shock is recorded, when the endotoxin was injected intravenously 4 hours after administration of 10 microg Streptococcus mitis exotoxin.

RESULTS

Only the protein precipitated by 20% (NH(4))(2)SO(4) (molecular weight is 34,000) from culture supernatant fluid was pyrogenic for rabbits (average temperature increase near 1 degrees C), and it can also cause the proliferation of rabbit splenocytes (mitogenicity). All the animals receiving subcutaneous injection of exotoxin containing purified proteins precipitated with higher concentrations of (NH(4))(2)SO(4) died within 16 approximately 29 hours after intravenous injection of the Escherichia coli endotoxin, demonstrating the enhanced susceptibility of the animals to lethal endotoxin shock. The control rabbits displayed none of these effects.

CONCLUSION

Streptococcus mitis exotoxin is a novel streptococcal pyrogenic exotoxin.