The promoter region of the CTLA4 gene is associated with type 1 diabetes mellitus

The CTLA4 (cytotoxic T lymphocyte associated antigen-4) gene encodes the T cell receptor involved in the control of T cell proliferation and mediates T cell apoptosis. C-T polymorphism is present at position -318 from the ATG start codon in the promoter region of the gene. We report a study on the polymorphism in 347 unrelated children with type 1 diabetes mellitus (DM) (age at diagnosis 7.2+/-3.8 years) and their 260 healthy siblings as controls. Genotype C/C conferred a risk of type 1 DM (RR = 2.02, 95% CI 1.32-3.10, pc = 0.0033). The gene frequency of the C allele was higher in patients (RR = 1.91, 95% CI 1.28-2.84, pc = 0.0026). The gene frequency and phenotype frequency of the T allele were negatively associated with type 1 DM (RR = 0.52, 95% CI 0.35-0.78, pc = 0.0026 and RR = 0.49, 95% CI 0.32-0.76, pc = 0.0022, respectively). The frequency of genotype C/T was lower in patients (RR = 0.50, 95% CI 0.32-0.78, pc = 0.0051). This study demonstrates that nucleotide -318 C-T polymorphism of the CTLA4 gene is associated with type 1 DM. The promoter allele -318 C confers a risk of type 1 DM but allele -318 T confers protection against this disease.

Mitogen-stimulated TIS21 protein interacts with a protein-kinase-Calpha-binding protein rPICK1

TIS21 is induced transiently by PMA and a number of extracellular stimuli. Yeast two-hybrid screening has identified three TIS21 interacting clones from a rat cDNA library [Lin, Gary, Yang, Clarke and Herschman (1996) J. Biol. Chem 271, 15034-15044]. The amino acid sequence deduced from clone 5A shows 96.9% identity with the murine PICK1, a protein kinase Calpha (PKCalpha)-binding protein postulated to act as an intracellular receptor for PKC. A fusion protein of glutathione S-transferase and rPICK1 associates with the TIS21 translated in vitro, suggesting a direct physical interaction between these two proteins. TIS21 and rPICK1 are co-immunoprecipitated from NIH 3T3 cells overexpressing these two proteins. This indicates that the interaction also occurs in mammalian cells. Deletion of the PDZ domain at the N-terminus of rPICK1 abolishes its interaction with TIS21. A putative carboxylate-binding loop required for PICK1 to bind PKCalpha [Staudinger, Lu and Olson (1997) J. Biol. Chem 272, 32019-32024] is within this deleted region. Our results suggest a potential competition between TIS21 and PKC for binding to PICK1. We show that recombinant TIS21 is phosphorylated by PKC in vitro. The catalytic activity of PKC towards TIS21 is significantly decreased in the presence of rPICK1, whereas phosphorylation of histone by PKC is not affected. rPICK1 seems to modulate the phosphorylation of TIS21 through specific interactions between these two proteins. TIS21 might have a role in PKC-mediated extracellular signal transduction through its interaction with rPICK1.

Sequences at the 3' untranslated region of bamboo mosaic potexvirus RNA interact with the viral RNA-dependent RNA polymerase

The 3' untranslated region (UTR) of bamboo mosaic potexvirus (BaMV) genomic RNA was found to fold into a series of stem-loop structures including a pseudoknot structure. These structures were demonstrated to be important for viral RNA replication and were believed to be recognized by the replicase (C.-P. Cheng and C.-H. Tsai, J. Mol. Biol. 288:555-565, 1999). Electrophoretic mobility shift and competition assays have now been used to demonstrate that the Escherichia coli-expressed RNA-dependent RNA polymerase domain (Delta 893) derived from BaMV open reading frame 1 could specifically bind to the 3' UTR of BaMV RNA. No competition was observed when bovine liver tRNAs or poly(I)(C) double-stranded homopolymers were used as competitors, and the cucumber mosaic virus 3' UTR was a less efficient competitor. Competition analysis with different regions of the BaMV 3' UTR showed that Delta 893 binds to at least two independent RNA binding sites, stem-loop D and the poly(A) tail. Footprinting analysis revealed that Delta 893 could protect the sequences at loop D containing the potexviral conserved hexamer motif and part of the stem of domain D from chemical cleavage.

Congenital lactic acidosis: evaluation of the properties of the a199t natural variant of human pyruvate dehydrogenase e1alpha by in vitro mutation

One cause of congenital lactic acidosis is a mutation in the E1 alpha-subunit of the pyruvate dehydrogenase multienzyme complex. Little is known about the consequences of these mutations at the enzymatic level. Here we study the A199T mutation by expressing the protein in Escherichia coli. The specific activity is 25% of normal and the K(m) for pyruvate is elevated by 10-fold. Inhibitors of lactate dehydrogenase might be a useful therapy for patients with such mutations.

Overexpression of copper-zinc superoxide dismutase attenuates acute activation of activator protein-1 after transient focal cerebral ischemia in mice

BACKGROUND AND PURPOSE

Reactive oxygen species (ROS) have been implicated in reperfusion injury after focal cerebral ischemia (FCI). ROS are known to regulate the activity of transcription factors such as activator protein-1 (AP-1), which is a dimer consisting of members of the Jun and Fos families. We investigated the role of ROS in AP-1 activity after FCI using transgenic mice that overexpressed copper-zinc superoxide dismutase (SOD1) and that had reduced infarction volume after FCI.

METHODS

The SOD1 transgenic mice and their wild-type littermates were subjected to middle cerebral artery occlusion and reperfusion by intraluminal suture blockade. After 60 minutes of middle cerebral artery occlusion, mice were allowed to recover for 1, 2, and 4 hours before euthanasia. Protein expression of c-Jun and c-Fos was examined by immunohistochemistry and Western blotting. AP-1 DNA-protein binding activity was assessed by electrophoretic mobility shift assays.

RESULTS

In wild-type mice, immunohistochemistry demonstrated acute c-Jun and c-Fos activation in ischemic cortex and its outer boundary. Expression of both was reduced in SOD1 transgenic mice. Western blotting confirmed that SOD1 overexpression was associated with reduced c-Jun and c-Fos protein levels in ischemic brain. Electrophoretic mobility shift assays revealed that the ischemia-enhanced DNA binding activity observed in wild-type mice was reduced in SOD1 transgenic mice. Supershift assays indicated that c-Jun participated in the bound AP-1 complex.

CONCLUSIONS

SOD1 overexpression prevents early activation of AP-1 after transient FCI in mice. This may block the expression of downstream target genes that are injurious, thereby reducing the infarction volume after transient FCI in mice.

Metabolic disturbance in obese children: glucose, insulin levels and lipid profile

Obesity is a common nutritional disorder among children and adolescents. The purpose of this study was to investigate the biochemical changes in obese children in Taiwan, in comparison with those observed by other authors. Children with weights above 120 percent of ideal body weight were considered obese. Serum glucose, insulin, uric acid, and creatinine levels and lipid profiles of 298 obese children (mean age 11.3 +/- 2.4 years, 158 boys) and 60 controls (mean age 11.6 +/- 2.2 years, 38 boys) were determined using accepted procedures. Demographic and serum biochemical characteristics were compared between obese and control groups overall and by gender. Serum glucose, insulin, cholesterol, and triglyceride levels, known risk factors for coronary heart disease, were higher in the obese patients than in the control group. Early treatment and prevention of childhood obesity may keep the metabolic disturbance from deteriorating and becoming risk factors for coronary heart disease.

Intra-thoracic failure pattern and survival status following 3D conformal radiotherapy for non-small cell lung cancer: a preliminary report

BACKGROUND

To study the intra-thoracic failure pattern, clinical target volume (CTV) and survival status following 3D conformal radiotherapy (3DCRT) boost for non-small cell lung cancer (NSCLC).

METHODS

From May 1994 through June 1998, 33 patients (26 male, seven female) with NSCLC were treated with a complete course of radiotherapy (RT) in our institute. Group A included 10 patients receiving radical operation and adjuvant postoperative RT. The other 23 patients (groups B and C) received definitive radiotherapy as local treatment. Among them there were seven cases as group B (stage I-II) and 16 cases as group C (stage III). Fifteen (15/33) patients received chemotherapy. The radiotherapy strategy constituted conventional AP/PA radiotherapy (RT) 19.8-45 Gy (median 39.6 Gy) plus 3DCRT boost 6-34.2 Gy (median 20 Gy). The median total tumor dose was 59.6 Gy (ranging from 39.8 to 64.8 Gy). Patients were followed up regularly (6/33) or until their death (27/33). Nineteen patients received follow-up chest computed tomography (CT). The relationship between intra-thoracic failure found by chest CT and the initial RT and boost RT fields was analyzed. Local failure was defined as one of the following: clinical disease progression, CXR progression or relapse noted by CT. The overall survival (OS) and local failure free survival (LFF) were obtained using the Kaplan-Meier method.

RESULTS

Sixteen intra-thoracic failures were noted in 15 follow-up chest CT examinations, which included nine in-field relapses, three partial in-field relapses and four out-field relapses. The 2-year OS and LFF for groups A, B and C were 78.8/59.2, 14.2/16.7 and 6.2/7.1% respectively. RTOG grade III/IV complications included one pneumothorax (RTOG grade III).

CONCLUSION

Our retrospective study showed that selective omission of contralateral mediastinal lymph node station irradiation may be appropriate in RT for NSCLC. Chest wall and pleural relapses may not be a negligible cause of intra-thoracic failure after RT for NSCLC.

Effect of percent free prostate-specific antigen measurement on improving the specificity of serum prostate-specific antigen testing in Taiwanese patients

BACKGROUND AND PURPOSE

Measurement of percent free prostate-specific antigen (fPSA) has been shown to enhance the diagnostic performance of traditional serum PSA determination. We sought to determine whether measurement of percent fPSA could improve the specificity of serum total PSA testing in the detection of prostate cancer in Taiwanese patients with intermediate serum PSA concentrations.

METHODS

The medical records of 211 patients examined from March 1998 through March 2000 were analyzed retrospectively; all had a serum total PSA concentration of between 4.1 and 20.0 ng/mL and negative digital rectal examination (DRE) findings, and had undergone a prostate biopsy. Biopsy results were correlated with the serum total PSA concentration and percent fPSA, which were determined using a microparticle enzyme immunoassay. Percent fPSA was calculated as the ratio of fPSA to total PSA multiple by 100. The sensitivity and specificity were calculated and the receiver operating characteristic (ROC) curves were generated from different cutoff values of percent fPSA and total PSA.

RESULTS

Thirty-four patients (16.1%) had positive biopsy results (prostate cancer). Patients with positive biopsy results had significantly lower percent fPSA values than those with negative results (11.7% vs 16.0%, p < 0.001). Patients with a lower percent fPSA (< 10%) had a higher probability of a positive biopsy result than those with a high percent fPSA (> 20%) (positive biopsy rate, 29% vs 10%, p < 0.05). Using a cutoff value of 25% fPSA or below, the sensitivity, specificity, and positive predictive value in differentiating patients with positive biopsy results from those with negative results were 97%, 13%, and 18%, respectively. Consequently, 27 unnecessary biopsies could have been avoided at the cost of missing one cancer. The area under the ROC curve was 0.68 for percent fPSA and 0.63 for total PSA (p > 0.05).

CONCLUSIONS

For Taiwanese patients with a serum PSA concentration of between 4.1 and 20.0 ng/mL, the incidence of prostate cancer is relatively low; measurement of percent fPSA only weakly enhances the specificity of serum PSA testing in detecting prostate cancer.

Clinical and histopathological characteristics of primary cutaneous amyloidosis in 794 Chinese patients

BACKGROUND

Primary cutaneous amyloidosis (PCA) is not uncommon in Chinese patients. The disease is usually persistent and quite pruritic. Patients who suffer from this disease usually respond poorly to conventional treatment. We thus reviewed our cases of PCA to discuss the clinical and pathological characteristics.

METHODS

Seven hundred and ninety-four Chinese patients with PCA who visited the Department of Dermatology, Taipei Veterans General Hospital during the last 26-year period were examined and retrospectively studied. The diagnosis in these patients was confirmed by histopathological studies.

RESULTS

Among the many types of PCA, lichen amyloidosis was the most common clinical variant (67%). Pure cases of macular amyloidosis accounted only 8% and were often associated with lichenoid lesions to form biphasic amyloidosis, which was composed of 25% in our series. Other rare types of PCA, such as nodular, anosacral, and vitiliginous amyloidosis, always required a careful differential diagnosis clinically from other similar skin disorders. In addition, 56 familial cases were found. Histopathologically, the most common epidermal findings of PCA were hyperkeratosis, irregular acanthosis with thinning of rete ridges, and expansion of dermal papillae by amyloid deposition. Special histochemical stains were helpful for confirming the existence of amyloid.

CONCLUSIONS

Our study represents the largest number of cases of PCA collected to date. Based on the data, most cases are sporadic, except 56 familial cases which may suggest the possible genetic role. Rare types of PCA, such as anosacral and vitiliginous amyloidosis which need special attention, compose a diagnostic challenge to a dermatologist. Histochemically, H&E stain can give a primary clue for the diagnosis of amyloidosis and crystal violet stain is a very simple and sensitive method to detect the existence of amyloid.

SOD1 down-regulates NF-kappaB and c-Myc expression in mice after transient focal cerebral ischemia

Reactive oxygen species (ROS) are implicated in reperfusion injury after focal cerebral ischemia (FCI). Reactive oxygen species regulate activity of transcription factors like NF-kappaB. The authors investigated the role of ROS in NF-kappaB activity after FCI using transgenic mice that overexpressed human copper/zinc-superoxide dismutase (SOD1) and that had reduced infarction volume after FCI. Superoxide dismutase transgenic and wild-type mice were subjected to 1 hour of middle cerebral artery occlusion (MCAO) and subsequent reperfusion. Immunohistochemistry showed SOD1 overexpression attenuated ischemia-induced NF-kappaB p65 immunoreactivity. Colocalization of NF-kappaB and the neuronal marker, microtubule-associated proteins (MAPs), showed that NF-kappaB was up-regulated in neurons after FCI. Electrophoretic mobility shift assays showed that SODI overexpression reduced ischemia-induced NF-kappaB DNA binding activity. Supershift assays showed that DNA-protein complexes contained p65 and p50 subunits. Immunoreactivity of c-myc, an NF-kappaB downstream gene, was increased in the ischemic cortex and colocalized with NF-kappaB. Western blotting showed that SOD1 overexpression reduced NF-kappaB and c-Myc protein levels in the ischemic brain. Colocalization of c-Myc and TUNEL staining was observed 24 hours after FCI. The current findings provide the first evidence that SOD1 overexpression attenuates activation of NF-kappaB after transient FCI in mice and that preventing this early activation may block expression of downstream deleterious genes like c-myc, thereby reducing ischemic damage.

Final height of children with type 1 diabetes: the effects of age at diagnosis, metabolic control, and parental height

Normal growth is one of the major goals in the treatment of children with type 1 diabetes. We prospectively monitored the linear growth and metabolic control of 44 children (13 boys) with type 1 diabetes from the time of diagnosis to the attainment of adult height and analyzed the relationship between the height and the age at diagnosis, metabolic control, and genetic target height. At diagnosis, girls at puberty were taller (height in standard deviation score: 0.60 +/- 0.94, p = 0.022), while boys (-0.03 +/- 0.67) and prepubertal girls (0.24 +/- 0.86) were similar to the age-controlled children. During the following years, they lost height compared to their height at diagnosis (p = 0.009), but they still attained an average final height (-0.13 +/- 0.66 in boys, -0.05 +/- 0.86 in girls) correlated with their height at diagnosis (r = 0.37, p = 0.014), as well as their genetic target height (r = 0.78, p < 0.005). The final height as well as the reduction in height was not linearly correlated with the age at diagnosis. The mean HbA1c level of the 44 children was 10.33 +/- 1.74%, boys had better control compared with girls (mean HbA1c 9.45 +/- 1.28 v.s. 10.71 +/- 1.78%, p = 0.013). The final height or the reduction in height was not linearly correlated with the mean HbA1c level.

Piroxicam and NS-398 rescue neurones from hypoxia/reoxygenation damage by a mechanism independent of cyclo-oxygenase inhibition

We studied whether NS-398, a selective cyclo-oxygenase-2 (COX-2) enzyme inhibitor, and piroxicam, an inhibitor of COX-2 and the constitutively expressed COX-1, protect neurones against hypoxia/reoxygenation injury. Rat spinal cord cultures were exposed to hypoxia for 20 h followed by reoxygenation. Hypoxia/reoxygenation increased lactate dehydrogenase (LDH) release, which was inhibited by piroxicam (180-270 microM) and NS-398 (30 microM). Cell counts confirmed the neuroprotection. Western blotting revealed no COX-1 or COX-2 proteins even after hypoxia/reoxygenation. Production of prostaglandin E2 (PGE2), a marker of COX activity, was barely measurable and piroxicam and NS-398 had no effect on the negligible PGE2 production. Hypoxia/reoxygenation increased nuclear factor-kappa B (NF-kappaB) binding activity, which was inhibited by piroxicam but not by NS-398. AP-1 binding activity after hypoxia/reoxygenation was inhibited by piroxicam but strongly enhanced by NS-398. However, both COX inhibitors induced activation of extracellular signal-regulated kinase (ERK) in neurones and phosphorylation of heavy molecular weight neurofilaments, cytoskeletal substrates of ERK. It is concluded that piroxicam and NS-398 protect neurones against hypoxia/reperfusion. The protection is independent of COX activity and not solely explained by modulation of NF-kappaB and AP-1 binding activity. Instead, piroxicam and NS-398-induced phosphorylation through ERK pathway may contribute to the increased neuronal survival.

Carcinosarcoma of ovary associated with previous radiotherapy

Carcinosarcoma is a rare neoplasm which, in the female genital tract, arises mainly in the endometrium. Although the pathogenesis remains obscure, there is an apparent association between pelvic irradiation and uterine sarcomas. There have been sporadic case reports of the development of carcinosarcomas of the cervix, vagina, and extragenital areas, but not of the ovary, after previous pelvic irradiation. We describe a case of ovarian carcinosarcoma arising in a 74-year-old female who had pelvic irradiation 33 years previously. Exploratory laparotomy showed a 25 x 18 x 9 cm left ovarian tumor with adjacent organ invasion including peri-uterine serosa and rectum. The patient was treated by optimal cytoreduction, followed by chemotherapy with adriamycin and cisplatin. However, acute hepatitis caused by reactivation of hepatitis B virus infection developed just before the fifth course of chemotherapy. She died of hepatic failure two weeks later.

Alteration in the expression of protein kinase C isoforms in human hepatocellular carcinoma

This study was designed to investigate the alterations of individual protein kinase C (PKC) isoforms in human liver cancer. Surgical specimens of hepatocellular carcinoma and adjacent normal tissues were extracted into cytosolic and membranous fractions. The level of membrane-bound PKCalpha in the cancer tissue was significantly lower than that in the adjacent normal tissue and consistent with the change in PKC activity. In addition, there was a significant negative correlation between PKCalpha and tumor size. In both cytosolic and membrane fractions, levels of PKCdelta and PKCzeta was significantly higher in the cancer tissue than those in the adjacent normal liver tissue. The alterations in the PKC isoforms signify their roles in the hyperproliferation in liver cancer.

Anosacral cutaneous amyloidosis: a study of 10 Chinese cases

BACKGROUND

Primary cutaneous amyloidoses are rare in Western countries, but are relatively common in Taiwan. Anosacral cutaneous amyloidosis is a rare type of primary cutaneous amyloidoses, first reported in Japanese patients.

PATIENTS/METHODS

In the present study, we investigated the age of onset, sites of involvement, associated systemic diseases, and histopathological findings in 10 cases of anosacral cutaneous amyloidosis seen during the past 27 years.

RESULTS

In previous reports the aetiology of anosacral cutaneous amyloidosis was thought to be a senile change, but half of our patients developed the disease before the age of 60 years. Based on our histopathological findings, apoptosis may be the initial event causing amyloid deposition, although the precise mechanism causing apoptosis needs further investigation. Three patients were found to have diabetes mellitus, but any relationship to anosacral cutaneous amyloidosis is unclear.

CONCLUSIONS

No cases of this cutaneous disorder have been reported in the Western literature; there seems to be a racial difference accounting for the disease, although the precise factor is not clarified yet. The disease could easily be misdiagnosed as lichen simplex chronicus, postinflammatory hyperpigmentation or tinea cruris; therefore, a thorough history, a careful physical examination and a skin biopsy is needed to establish a firm diagnosis.

Virulence of Vibrio parahaemolyticus isolated from cultured small abalone, Haliotis diversicolor supertexta, with withering syndrome

Outbreaks of mass mortality among cultured small abalone Haliotis diversicolor supertexta with withering syndrome occurred in May and September 1998 in Kao-Hsiung, Taiwan. Bacterial strains CH-1 and B4 were isolated from the haemolymph of the moribund small abalone using tryptic soy agar supplemented with 3% NaCl and/or thiosulphate citrate bile salt sucrose agar. These two strains were characterized and identified as Vibrio parahaemolyticus on the basis of various biochemical tests. The B4 strain and its extracellular products were virulent to small abalone with LD(50) values of 1.6 x 10(5) colony-forming units and 7.58 microg protein g-1 body weight, respectively.

Effects of repetitive subfailure strains on the mechanical behavior of the inferior glenohumeral ligament

The mechanical response of the inferior glenohumeral ligament to varying subfailure cyclic strains was studied in 33 fresh frozen human cadaver shoulders. The specimens were tested as bone-ligament-bone preparations representing the 3 regions of the inferior glenohumeral ligament (superior band and anterior and posterior axillary pouches) through use of uniaxial tensile cycles. After mechanical preconditioning, each specimen was subjected to 7 test segments, consisting of a baseline strain level L1 (400 cycles) alternating with either 1 (group A, 10 shoulders), 10 (group B, 13 shoulders), or 100 (group C, 10 shoulders) cycles at increasing levels (L2, L3, L4) of subfailure strain. Cycling to higher levels of subfailure strain (L2, L3, L4) produced dramatic declines in the peak load response of the inferior glenohumeral ligament for all specimens. The group of ligaments subjected to 100 cycles of higher subfailure strains demonstrated a significantly greater decrease in load response than the other 2 groups. Ligament elongation occurred with cyclic testing at subfailure strains for all 3 groups, averaging 4.6% +/- 2.0% for group A, 6.5% +/- 2.6% for group B, and 7.1% +/- 3.2% for group C. Recovery of length after an additional time of nearly 1 hour was minimal. The results from this study demonstrate that repetitive loading of the inferior glenohumeral ligament induces laxity in the ligament, as manifested in the peak load response and measured elongations. The mechanical response of the ligament is affected by both the magnitude of the cyclic strain and the frequency of loading at the higher strain levels. The residual length increase was observed in all of the specimens and appeared to be largely unrecoverable. This length increase may result from accumulated microdamage within the ligament substance, caused by the repetitively applied subfailure strains. The clinical relevance of the study is that this mechanism may contribute to the development of acquired glenohumeral instability, which is commonly seen in the shoulders of young athletes who participate in repetitive overhead sports activities.

Characterization of chemoresistance mechanisms in a series of cisplatin-resistant transitional carcinoma cell lines

We explored the mechanisms of cisplatin resistance in a series of bladder transitional carcinoma cells that are either sensitive or progressively resistant to cisplatin. Resistant lines were raised by chronic exposure of the parental cells to progressively increased concentrations of cisplatin. The cisplatin IC50s of the sensitive and the three resistant cells were 4.3, 25.0, 40.4, and 52.2 microM, respectively. The expressions of glutathione S-transferase pi (GST-pi) and multidrug resistance-associated protein (MRP) were enhanced in a dose-response manner as cells acquired progressive cisplatin resistance. Expression of mdr-1 transcript was detected in the three resistant lines but not in the sensitive line. Glutathione contents were increased in resistant cells, yet the trend of increase did not reach statistical significance (p = 0.061). In conclusion, transitional carcinoma cells may gain cisplatin resistance through multiple pathways including up-regulation of GST-pi, MRP and possibly mdr-1. Glutathione contents may play a less significant role in cisplatin chemoresistance.

Hydrogen peroxide induces apoptosis in human hepatoma cells and alters cell redox status

Direct exposure of human hepatoma cell line SMMC-7721 to hydrogen peroxide (H2O2) can induce apoptosis. Apoptosis induced by H2O2 was inhibited by cycloheximide, actinomycin D, 3-aminobenzamide, EGTA or Zn2+. H2O2 can increase the level of intracellular Ca2+, downregulate GSH levels, slightly induce lipid peroxidation, and lead to change in the ratio of reduced ion components to oxidized ion components of cells. Analysis of flow cytometry indicates that H2O2 decreases the level of Bcl-2. The data indicate that H2O2-induced apoptosis requires new mRNA and protein syntheses; H2O2 can activate Ca2+/Mg2+-dependent endonuclease leading to internucleosomal DNA fragmentation and activation of poly (ADP-ribose) polymerase interfering with the energy metabolism of the cell. The H2O2 downregulation of GSH may be more important for apoptosis than H2O2 induction of lipid peroxidation, and the H2O2 induced changes in redox status of the cell may be among the original events which lead up to other biochemical changes.

Development of brain injury in mice by Angiostrongylus cantonensis infection is associated with the induction of transcription factor NF-kappaB, nuclear protooncogenes, and protein tyrosine phosphorylation

Eosinophilic meningitis or meningoencephalitis caused by Angiostrongylus cantonensis is endemic to the Pacific area of Asia, especially Taiwan, Thailand, and Japan. Although eosinophilia is an important clinical manifestation of A. cantonensis infection, the role of eosinophils in the progress of the infection remains to be elucidated. In this experiment, we showed that A. cantonensis-caused eosinoplia and inflammation might lead to the induction of NF-kappaB and protooncogene expression via activation of the tyrosine phosphorylation signal pathway. After mice were infected daily with 30 third-stage larvae of A. cantonensis by oral adminstration for 6 weeks, no significant differences PKC-alpha, MEK-1, ERK-2, JNK, and p38 protein expression were found between the control and infected mice. However, the protein tyrosine phosphorylation levels, NF-kappaB, and iNOS protein products were significantly increased by 3.5-, 3.3-, and 6.3-fold, respectively, after 3 weeks of A. cantonensis infection. The same pattern was found for c-Myc, c-Jun, and c-Fos proteins, which were elevated by 3.2-, 2.3-, and 3.4-fold, respectively, compared to control animals after 3 weeks. The expression potency of these proteins started increasing in week 1, reaching maximal induction in week 3, and then declining in week 5 after A. cantonensis infection. Another consistent result was noted in the pathological observations, including eosinophilia, leukocyte infiltration, granulomatous reactions, and time responses in brain tissues of infected mice. These data suggest that the development of brain injury by eosinophlia of A. cantonensis infection is associated with NF-kappaB and/or nuclear protooncogenes expression, which is activated by the tyrosine phosphorylation pathway.

Clinical experience in using polymerase chain reaction for rapid diagnosis of pulmonary tuberculosis

BACKGROUND

Polymerase chain reaction (PCR) techniques have revolutionized the diagnosis of tuberculosis (TB). PCR has significantly improved the sensitivity and specificity of existing diagnostic methods. In this study, we report our experience using a modified IS6110-based nested PCR assay for rapid diagnosis of pulmonary TB.

METHODS

A total of 327 respiratory specimens from 275 patients suspected of having pulmonary TB at Taipei Veterans General Hospital were tested using the nested PCR assay, acid-fast smear and culture for the presence of Mycobacterium tuberculosis complex (MTB). Nested PCR was performed with IS6110-based primers specific for MTB. We reviewed the medical records of patients and analyzed the clinical features. The PCR results were compared with the final clinical diagnosis.

RESULTS

We identified MTB in 167 of 327 samples by the nested PCR assay. No non-tuberculous Mycobacterium (NTM) was identified among the clinical samples. Diagnosis by PCR took about 6 hours in this study. The sensitivity and specificity compared with culture were 94.7% and 100%, respectively for the smear-positive, culture-positive samples, and 76.7% and 98.6% for the smear-negative, culture-positive samples. The overall sensitivity, specificity, positive and negative predictive values, compared with culture results, were 91.7%, 98.6%, 98.8% and 90.6%, respectively. Two specimens positive by PCR and negative by culture were taken from patients on anti-TB drug therapy. These specimens were culture-positive before anti-TB drug therapy. After resolution of the discrepancies by studying the patients' clinical data, both specificity and positive predictive value reached 100%.

CONCLUSIONS

The results indicated that this in-house nested PCR assay is a rapid and sensitive method for diagnosing pulmonary TB. It is also good for excluding infections caused by NTM.

A unified sampling approach for multipoint analysis of qualitative and quantitative traits in sib pairs

Recent advances in molecular biology have enhanced the opportunity to conduct multipoint mapping for complex diseases. Concurrently, one sees a growing interest in the use of quantitative traits in linkage studies. Here, we present a multipoint sib-pair approach to locate the map position (tau) of a trait locus that controls the observed phenotype (qualitative or quantitative), along with a measure of statistical uncertainty. This method builds on a parametric representation for the expected identical-by-descent statistic at an arbitrary locus, conditional on an event reflecting the sampling scheme, such as affected sib pairs, for qualitative traits, or extreme discordant (ED) sib pairs, for quantitative traits. Our results suggest that the variance about tau&d4;, the estimator of tau, can be reduced by as much as 60%-70% by reducing the length of intervals between markers by one half. For quantitative traits, we examine the precision gain (measured by the variance reduction in tau&d4;) by genotyping extremely concordant (EC) sib pairs and including them along with ED sib pairs in the statistical analysis. The precision gain depends heavily on the residual correlation of the quantitative trait for sib pairs but considerably less on the allele frequency and exact genetic mechanism. Since complex traits involve multiple loci and, hence, the residual correlation cannot be ignored, our finding strongly suggests that one should incorporate EC sib pairs along with ED sib pairs, in both design and analysis. Finally, we empirically establish a simple linear relationship between the magnitude of precision gain and the ratio of the number of ED pairs to the number of EC pairs. This relationship allows investigators to address issues of cost effectiveness that are due to the need for phenotyping and genotyping subjects.

Polymorphism in the transmembrane region of the MICA gene and type 1 diabetes

Although MHC class II genes have a stronger association with type 1 diabetes than MHC class I genes, studies have shown that MHC class I molecules play an independent role in the etiology of type 1 diabetes, and the existence of susceptibility genes within a segment of MHC between the HLA-B and TNF genes has been predicted, where MHC class I chain-related gene A (MICA) resides. MICA has a triplet repeat polymorphism in the transmembrane region consisting of five alleles. We analyzed this polymorphism in 162 unrelated children (82 boys) with type 1 diabetes (age at diagnosis 7.01 +/- 3.76 yr) and 154 randomly selected unrelated children (87 boys), age 2.81 +/- 2.12 yr. Phenotype frequency of allele A9 in children with type 1 diabetes was significantly higher than in controls (RR = 2.42, 95% CI = 1.52-3.85, p = 0.000162, pc = 0.00081). Gene frequency of allele A9 was also significantly higher in children with type 1 diabetes when compared with control children (RR = 2.73, 95% CI = 1.85-4.03, p = 2.62 x 10(-7), pc = 1.31 x 10(-6)). This study demonstrates that MICA allele A9 confers risk of type 1 diabetes.