High sensitivity photoconductivity based measurement setup for the determination of effective recombination lifetime in silicon wafers

We describe a high sensitivity measurement setup for the determination of recombination parameters in semiconductors at low levels of carrier injection. The setup is based on a lock-in amplifier and on a commercially available contactless conductivity detector. The information on recombination is extracted through the analysis, assuming quasi-steady-state conditions, of the low frequency, sinusoidally modulated photoconductivity signal induced by the illumination of a 950 nm light emitting diode array. Experimental results show a substantial increase in sensitivity with respect to traditional transient or quasi-steady-state techniques based on the same detection principle. The sensitivity bonus can be exploited for the extension of the carrier injection range for which effective recombination lifetime is measurable, both in the case of p-type and n-type wafers.

Regulation of the hTERT promoter activity by MSH2, the hnRNPs K and D, and GRHL2 in human oral squamous cell carcinoma cells

Higher expression of human telomerase reverse transcriptase (hTERT) and subsequent activation of telomerase occur during cellular immortalization and are maintained in cancer cells. To understand the mode of hTERT expression in cancer cells, we identified cancer-specific trans-regulatory proteins that interact with the hTERT promoter, using the promoter magnetic precipitation assay coupled to mass spectrometry (PMS-MS). The identified proteins include MutS homologue 2 (MSH2), heterogeneous nuclear ribonucleoprotein (hnRNP) D, hnRNP K, and Grainyhead-like 2 (GRHL2). We noticed higher expression of these proteins in human oral squamous cell carcinoma (OSCC) cells than in normal cells, which do not exhibit telomerase activity. Knockdown of MSH2, hnRNP D and GRHL2 resulted in notable reduction of the hTERT promoter activity in tested cancer cells. Silencing of the above genes resulted in the significant reduction of telomerase activity in OSCC cells. Interestingly, among the four identified genes, silencing of GRHL2 was essential in reducing telomerase activity and viability of tested cancer cells. These results suggest a possible role of GRHL2 in telomerase activation during cellular immortalization.

High affinity Fc receptor binding and potent induction of antibody-dependent cellular cytotoxicity (ADCC) in vitro by anti-epidermal growth factor receptor antibody cetuximab

3041

Background: Cetuximab is an IgG1 monoclonal antibody specific for human epidermal growth factor receptor (EGFR). Cetuximab acts as a functional antagonist by blocking ligand (EGF and TGFa) binding to EGFR and, therefore, inhibits EGFR activation and downstream signaling in tumor cells. Methods: In the present study, we analyzed the binding activity of cetuximab to human Fc receptors and tested whether cetuximab can elicit antibody-dependent cellular cytotoxicity (ADCC) in vitro using tumor cell lines expressing various levels of EGFR. Results: Cetuximab bound to human FcRI and FcRIII with high affinity (EC50 of 0.13 nM and 6 nM, respectively), whereas an aglycosylated form of cetuximab or an IgG2 antibody to EGFR (panitumumab) did not bind to FcRI and FcRIII. A panel of head and neck, colon, and breast tumor cell lines were tested for cetuximab-mediated ADCC using human peripheral blood mononuclear cells (PBMC) from normal donors as effector cells. We found that cetuximab-induced ADCC to these tumor cell lines ranging from 20–90% specific killing. Interestingly, the extent of ADCC induced by cetuximab correlated with the level of EGFR expression on cell surface. The aglycosylated form of cetuximab or panitumumab, did not elicit ADCC of EGFR expressing tumor cells, even though cetuximab and panitumumab bind to EGFR with similar affinity (Kd=87 pM and 83 pM, respectively). To identify the immune cell population responsible for ADCC, NK cells were isolated from PBMC and tested in an ADCC assay. Purified NK cells elicited high levels of specific killing of cetuximab bound tumor cells, suggesting that NK cells are one of effector cell populations in human PBMCs responsible for the observed ADCC activity. Conclusions: Thus, cetuximab can effectively link effector cells to EGFR expressing tumor cells and mediate potent ADCC against EGFR-expressing human tumors.

[Table: see text]

Protective effects of Ginkgo biloba extract on paraquat-induced apoptosis of PC12 cells

Previous studies have suggested that Ginkgo biloba extract (EGb761) has a protective potentiality against apoptosis of neurons or neuron-like cells induced by MPTP. In this study, the effects of EGb761 on PC12 cells injured by paraquat (PQ), a neurotoxin, were tested. The results showed that after incubation of PC12 cells with EGb761 prior to PQ exposure, the PQ-induced decrease of cell viability was significantly reversed, the collapse of mitochondrial membrane potential (MMP) was attenuated and the percentage of apoptotic cells was reduced. Moreover, EGb761 pretreatment evidently increased the numbers of tyrosine hydroxylase (TH) positive and bcl-2 positive cells and degraded the number of caspase-3 positive cells in PQ-injured PC12 cells, in comparison to the treatment with PQ alone. This study indicates that EGb761 has a neuroprotective effect on paraquat-induced apoptosis of PC12 cells. The mechanism underlying the protective effects of EGb761 in PQ-injured PC12 cells might be related to the increase of bcl-2 activation, maintenance of MMP stability and decrease of caspase-3 activation through mitochondria-dependent pathway. The results from this study provide an experimental basis for the potential use of EGb761 in treatment of Parkinson's disease.

Differentiation-dependent regulation of the cyclooxygenase cascade during adipogenesis suggests a complex role for prostaglandins

AIM

A thorough understanding of the mechanisms of adipocyte differentiation and metabolism is important for the prevention and/or treatment of obesity and its complications, including type 2 diabetes mellitus. A complex role for prostaglandins (PGs) in adipogenesis is suggested. We examined the expression and cellular localization of enzymes in the cyclooxygenase (COX) cascade that synthesize PGs as well as the PG profile as a function of differentiation status in 3T3-L1 cells.

METHODS

Murine 3T3-L1 preadipocytes were used as a model for studies of adipocyte differentiation induced by a hormone cocktail and compared with the parental fibroblastic line NIH 3T3. Both cell lines were incubated in maintenance medium or differentiation medium. Nine days after differentiation, the expression of enzymes in the COX cascade was evaluated by immunoblot analysis, reverse transcriptase-polymerase chain reaction (RT-PCR) and immunocytochemistry, and PG formation was examined using enzyme immunoassay.

RESULTS

A differentiation-dependent diminution of COX-1 and COX-2 mRNA and cognate proteins in 3T3-L1 cells was observed. PG release, including PGE(2), 6-keto PGF(1alpha), PGD(2) and 15d-PGJ(2), significantly decreased following differentiation in 3T3-L1 cells (anova/Tukey, p < 0.05). However, microsomal PGE synthase (mPGES) and lipocalin-type PGD synthase (L-PGDS) were selectively upregulated. Immunocytochemistry revealed that COX-1 and COX-2 became intracellularly more diffuse upon differentiation, whereas mPGES was redistributed to the nuclear compartment.

CONCLUSIONS

Regulation of PG formation and COX-2 expression in 3T3-L1 cells is differentiation-dependent and involves changes in the levels of gene expression of the individual isoforms as well as redistribution of the enzymes within cellular compartments.

Telomerase activity and the subunit of telomerase in hydatidiform mole and their relationship with the development of postmolar tumor

OBJECTIVES

To investigate the pattern of telomerase activity and the subunit of telomerase in normal placentae and GTD, and to determine the prognostic significance of telomerase activity and the subunit of telomerase in GTD.

METHODS

Telomerase activity human telomerase (hTERT) and human telomerase (hTR) expression were analyzed in the initial uterine evacuation specimen of 63 hydatidiform moles (HMs), 42 normal human placental tissues, 17 malignant gestational trophoblastic tumors, primary cultures of normal villi and JAR cell lines by use of the polymerase chain reaction-based telomeric repeat amplification protocol (TRAP) assay and reverse transcription-polymerase chain reaction (RT-PCR) methods.

RESULTS

Telomerase activity was 100% in primary cultures of normal villi and JAR cell lines and in less than 60-day early placental villi, while only 9.1% in greater than 60-day placental villi, 27% in HMs and 58% in malignant trophoblastic tumors. High levels of hTR could be found in all groups. hTR expression was detected in all cases of < 60-day placental villi, in 72.7% > 60-day placental villi, in 87.3% in HMs and 100% in malignant trophoblastic tumors. Telomerase activity and hTERT expression had significant differences among the groups. Telomerase activity was associated with serum hCG levels but not related to other clinical risk factors.

CONCLUSIONS

Telomerase activity may be correlated with the development of trophoblastic tumors, and hTERT may be a useful diagnostic marker for detecting the existence of malignant trophoblastic cells.

Antiangiogenic activity of BAI1 in vivo: implications for gene therapy of human glioblastomas

Glioblastomas are the most common primary brain tumors in adults. These tumors exhibit a high degree of vascularization, and malignant progression from astrocytoma to glioblastoma is often accompanied by increased angiogenesis and the upregulation of vascular endothelial growth factor and its receptors. In this study, we investigated the in vivo antiangiogenic and antitumor effects of brain-specific angiogenesis inhibitor 1 (BAI1) using human glioblastoma cell lines. Glioblastoma cells were transduced with an adenoviral vector encoding BAI1 (AdBAI1), and Northern and Western blot analyses, respectively, demonstrated BAI1 mRNA and protein expression in the transduced tumor cells. Using an in vivo neovascularization assay, we found that angiogenesis surrounding AdBAI1-transduced glioblastoma cells transplanted into transparent skinfold chambers of SCID mice was significantly impaired compared to control treated cells. Additionally, in vivo inoculation with AdBAI1 of established subcutaneous or intracerebral transplanted tumors significantly impaired tumor growth and promoted increased mouse survival. Morphologically, the tumors exhibited signs of impaired angiogenesis, such as extensive necrosis and reduced intratumoral vascular density. Taken together, these data strongly indicate that BAI1 may be an excellent gene therapy candidate for the treatment of brain tumors, especially human glioblastomas.

Effective transduction and stable transgene expression in human blood cells by a third-generation lentiviral vector

Difficulty in gene transduction of human blood cells, including hematopoietic stem cells, has hampered the development of gene therapy applications for hematological disorders, encouraging the development and use of new gene delivery systems. In this study, we used a third-generation self-inactivating (SIN) lentiviral vector system based on human immunodeficiency virus type 1 (HIV-1) to improve transduction efficiency and prevent vector-related toxicity. The transduction efficiency of the HIV-1-based vector was compared directly with the Moloney murine leukemia virus (MLV) SIN vector in human leukemia cell lines. Initial transduction efficiencies were almost 100% for the HIV and less than 50% for the MLV vectors. Similar results were observed in 11 types of primary cells obtained from leukemia or myeloma patients. Transgene expression persisted for 8 weeks in cells transduced with the HIV vector, but declined with the MLV vector. In addition, resting peripheral blood lymphocytes and CD34(+) hematopoietic cells were transduced successfully with the HIV vector, but not with the MLV vector. Finally, we confirmed vector gene integration in almost all colony-forming cells transduced with the HIV vector, but not with the MLV vector. In conclusion, this lentiviral vector is an excellent gene transduction system for human blood cells because of its high gene transduction and host chromosome integration efficiency.

Quantitative analysis of regional motion and thickening by gated myocardial perfusion SPECT: normal heterogeneity and criteria for abnormality

Quantitation of regional myocardial function is valuable in patients with coronary artery disease. This study assessed normal heterogeneity and developed and validated normal limits for quantitative regional motion and thickening by gated myocardial perfusion SPECT.

METHODS

Patients underwent rest (201)Tl/exercise (99m)Tc-sestamibi gated SPECT. Reference values of motion and thickening for 20 myocardial segments were obtained in 105 patients with <5% likelihood of coronary disease (low-likelihood group). Criteria for abnormality of motion and thickening were defined for each segment, using receiver operator characteristic analysis, in 101 patients with coronary disease (training group). Semiquantitative visual interpretation was used as the gold standard. These criteria were prospectively validated in 100 patients (validation group). Criteria for grading motion and thickening abnormalities by severity levels were also defined and validated.

RESULTS

Normal thickening decreased substantially along the longitudinal axis of the left ventricle, from 69% +/- 13% at the apex to 25% +/- 11% at the basal segments, whereas normal motion varied within the same ventricular plane. Validation of the criteria for abnormality yielded high accuracy in the detection of motion abnormalities (sensitivity, 88%; specificity, 92%) and thickening abnormalities (sensitivity, 87%; specificity, 89%). Quantitative motion and thickening segmental scores showed good agreement with visual scores.

CONCLUSION

Normal regional myocardial contraction by gated myocardial perfusion SPECT is characterized by a substantial apex-to-base decline in thickening and by circumferential heterogeneity in endocardial motion. The assignment of segment-specific threshold values for defining motion and thickening abnormalities provided reasonably accurate identification and grading of regional myocardial dysfunction.

Expression of the Huntington's disease transgene in neural stem cell cultures from R6/2 transgenic mice

Huntington's disease (HD) is an inherited neurodegenerative disorder resulting in neuronal cell death in discrete brain regions due to an expanded CAG repeat of the huntingtin gene. The transgenic mouse model R6/2 expresses exon 1 of the human huntingtin gene with >150 CAG repeats, which produces mutant HD protein with an expanded poly-glutamine tract. We have established a neuronal stem cell system deriving from transgenic HD R6/2 neonatal brains as a renewable source for neurons and glia to facilitate studies of HD neuropathology and therapies. These R6/2 stem cell cultures can be cryopreserved and revived. Thawed neural progenitors can be expanded, established as continuous cell lines, and induced to differentiate into glia and neurons. Using standard culture conditions, there was no detectable morphological difference between wild type and HDR6/2 cells. Western analysis reveals that R6/2, but not wild type neurospheres, express the expanded repeat transgenic protein. Immunocytochemistry reveals that at a higher antibody concentration, huntingtin can be localized in the nucleus and the cytoplasm of wild type and R6/2 cells. We conclude that the R6/2 neuronal stem cell culture is a valuable tool for investigating HD pathogenesis and potential genetic or pharmacological interventions.

Hydrodynamic characteristics and mixing behaviour of Sclerotium glucanicum culture fluids in an airlift reactor with an internal loop used for scleroglucan production

The filamentous fungus, Sclerotium glucanicum NRRL 3006, was cultivated in a 0.008 m(3) airlift bioreactor with internal recirculation loop (ARL-IL) for production of the biopolymer, scleroglucan. The rheological behaviour of the culture fluid was characterised by measurement of the fluid consistency coefficient (K) and the flow behaviour index (n). Based on these measurements, the culture fluid changed from a low viscosity Newtonian system early in the process, to a viscous non-Newtonian (pseudoplastic) system. In addition, reactor hydrodynamics and mixing behaviour were characterised by measurement of whole mean gas hold-up (epsilon(g)), liquid re-circulation velocity (U(ld)) and mixing time (t(m)). Under identical process conditions, the effects of the viscosity of the culture fluid and air flow rate on epsilon(g), U(ld) and t(m) were examined and empirical correlations for epsilon(g), U(ld) and t(m) with both superficial velocity U(g) and consistency coefficient K were obtained and expressed separately. The correlations obtained are likely to describe the behaviour of real fungal culture fluids more accurately than previous correlations based on Newtonian or simulated non-Newtonian systems.

Controlled nucleation and growth of surface-confined gold nanoparticles on a (3-aminopropyl)trimethoxysilane-modified glass slide: a strategy for SPR substrates

The thickness of the gold film and its morphology, including the surface roughness, are very important for getting a good, reproducible response in the SPR technique. Here, we report a novel alternative approach for preparing SPR-active substrates that is completely solution-based. Our strategy is based on self-assembly of the gold colloid monolayer on a (3-aminopropyl)trimethoxysilane-modified glass slide, followed by electroless gold plating. Using this method, the thickness of films can be easily controlled at the nanometer scale by setting the plating time in the same conditions. Surface roughness and morphology of gold films can be modified by both tuning the size of gold nanoparticles and agitation during the plating. Surface evolution of the Au film was followed in real time by UV-vis spectroscopy and in situ SPRS. To assess the surface roughness and electrochemical stability of the Au films, atomic force microscopy and cyclic voltammetry were used. In addition, the stability of the gold adhesion is demonstrated by three methods. The as-prepared Au films on substrates are reproducible and stable, which allows them to be used as electrodes for electrochemical experiments and as platforms for studying SAMs.

Serial changes on quantitative myocardial perfusion SPECT in patients undergoing revascularization or conservative therapy

BACKGROUND

Little is known about changes of myocardial perfusion in patients undergoing coronary revascularization or medical therapy. The purpose of this observational study was to assess the long-term effects of revascularization or conservative therapy on serial quantitative myocardial perfusion single photon emission computed tomography (SPECT).

METHODS AND RESULTS

The study population consisted of 421 patients who underwent serial rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion SPECT with at least a 1-year interval between the 2 studies and who had abnormal quantitative scan results on the first stress SPECT. The mean interval between scans was 32.7 +/- 15.9 months. Patients were divided into 3 groups according to stress defect extent: group 1 had small stress defects (4%-10%, n = 145), group 2 had intermediate stress defects (>10%-20%, n = 144), and group 3 had extensive stress defects (>20%, n = 132) at baseline. Forty patients in group 1, 44 in group 2, and 54 in group 3 underwent coronary revascularization between 2 SPECT studies; the others had conservative therapy. In group 3 patients with revascularization, stress defect extent and reversible defect extent were remarkably reduced (14.5% +/- 13.6% and 13.1% +/- 12.5%, respectively; both P <.0001), with greater improvement in those patients reporting increased use of cardiac medications; resting defect extent was slightly reduced (1.9% +/- 6.4%, P <.05). In group 3 patients with conservative therapy, a small reduction in stress defect extent was noted (2.3% +/- 8.3%, P <.05). In group 2, there were modest, similar reductions in reversible defect extent in both the patients with revascularization (2.7% +/- 7.7%, P <.05) and those with conservative therapy (1.8% +/- 7.3%, P <.05), as well as a small but significant reduction in stress defect extent in those with conservative therapy (2.1% +/- 8.2%, P <.05). In group 1 patients, no significant changes in stress, rest, or reversible defect extent were found with either therapy.

CONCLUSIONS

The findings of this study show that improvement in quantitative myocardial perfusion abnormalities over time occurs in some patients with either revascularization or conservative therapy and suggest that, in patients with extensive defects, greater improvement may be seen in those who undergo revascularization.

Prediction of myocardial infarction versus cardiac death by gated myocardial perfusion SPECT: risk stratification by the amount of stress-induced ischemia and the poststress ejection fraction

The combination of myocardial perfusion and poststress ejection fraction (EF) provides incremental prognostic information. This study assessed predictors of nonfatal myocardial infarction (MI) versus cardiac death (CD) by gated myocardial SPECT and examined the value of integrating the amount of ischemia and poststress EF data in risk stratification.

METHODS

We identified 2,686 patients who underwent resting (201)Tl/stress (99m)Tc-sestamibi gated SPECT and were monitored for >1 y. Patients who underwent revascularization < or = 60 d after the nuclear test were censored from the prognostic analysis. Visual scoring of perfusion images used 20 segments and a scale of 0--4. Poststress EF was automatically generated.

RESULTS

Cox regression analysis showed that after adjusting for prescan data, the most powerful predictor of CD was poststress EF, whereas the best predictor of MI was the amount of ischemia (summed difference score [SDS]). Integration of the EF and SDS yielded effective stratification of patients into low-, intermediate-, and high-risk subgroups. Patients with EF >50% and a large amount of ischemia were at intermediate risk (2%--3%), whereas those with mild or moderate ischemia were at low risk of CD (<1%/y). Patients with EF between 30% and 50% were at intermediate risk even in the presence of only mild or moderate ischemia. In patients with EF <30%, the CD rate was high (>4%/y) irrespective of the amount of ischemia.

CONCLUSION

Poststress EF is the best predictor of CD, whereas the amount of ischemia is the best predictor of nonfatal MI. Integration of perfusion and function data improves stratification of patients into low, intermediate, and high risk of CD.

[Study of Newcastle disease virus in the treatment of human laryngeal squamous carcinoma]

OBJECTIVE

To explore the biological value of newcastle disease virus in the therapy of human laryngocarcinoma.

METHODS

Nude mice model bearing laryngocarcinoma were established using human laryngeal squamous carcinoma cell line (Hep-2). Large amounts of Newcastle disease virus(NDV) were injected into the tumor. Changes in carcinoma administrated with the NDV were observed under light and electron microscopes. Isolation of NDV was attempted and sera were examined using the method of enzyme-linked immunosorbent assay (ELISA).

RESULTS

The difference between experimental and control groups was statistically significant, including the average weight of the mice: t' = 2.397 (P < 0.05), the average weight of the tumor tissue: t' = 2.852 (P < 0.05) and the average volume of the tumor tissue: t' = 6.058 (P < 0.01). In the experimental group, the NDV was isolated in the tumor tissue and ELISA was positive. The necrosis of the tumor cell and inflammatory cellular infiltration were found under light and electron microscopes.

CONCLUSION

These results indicated that NDV was effective in the treatment of laryngocarcinoma and had no damage to normal tissue.

When to stress patients after coronary artery bypass surgery? Risk stratification in patients early and late post-CABG using stress myocardial perfusion SPECT: implications of appropriate clinical strategies

OBJECTIVES

The study compared the prognostic significance of myocardial perfusion single-photon emission computed tomography (SPECT) (MPS) in patients early and late after coronary artery bypass graft surgery (CABG).

BACKGROUND

The long-term effectiveness of CABG is limited by graft stenosis. The greatest incidence of graft occlusion occurs between five and eight years after surgery. However, little is known regarding the appropriate time to stress patients post-CABG with respect to risk stratification.

METHODS

We identified 1,765 patients, who underwent MPS 7.1 +/- 5.0 years post-CABG. All patients underwent rest T1-201/stress Tc-99m sestamibi MPS and were followed up > or =1 year after testing. Patients with early CABG or PTCA (<60 days after MPS) were censored. The prognostic population consisted of 1,544 patients. A semiquantitative visual analysis employing a 20-segment model was used to define summed stress score (SSS), summed rest score (SRS), summed difference score (SDS), and the number of nonreversible segments (NRS).

RESULTS

During follow-up, 53 cardiac deaths (CD) occurred. There was a significant increase in annual CD rates as a function of SSS. A multivariate analysis identified age, ischemia (SDS), and infarct size (NRS) as independent predictors of CD. Nuclear variables added incremental value to prescan information. The annual CD rate was relatively low (1.3%) in patients < or =5 years post-CABG. In this subgroup only age and infarct size (NRS) were predictive of CD.

CONCLUSION

MPS is strongly predictive of subsequent CD in post-CABG patients and adds incremental value over clinical and treadmill test information. Our data suggest that symptomatic patients < or =5 years and all patients >5 years post-CABG may benefit from testing.

Analysis of the measurement precision of arterial lumen and wall areas using high-resolution MRI

High-resolution MRI may be used to monitor the progression of human carotid atherosclerosis by measuring the lumen and wall area changes over time. The purpose of this study was to analyze the precision of quantitative measurements of lumen and wall areas. Two independent MR scans near the carotid bifurcation were conducted on eight patients within 2 weeks. The error of lumen area measurement was 6. 2%, 9.2%, and 9.7% for T(1), proton density, and T(2)-weighted images, respectively, and the error of wall area measurement was 10. 8%, 10.9%, and 12.0%. The precision of area measurement correlates strongly with image quality.

Control of transcription in the RORa-staggerer mutant mouse cerebellum: glutamate receptor delta2 mRNA

The staggerer (transcription factor RORa-deleted) mutation blocks cerebellar Purkinje cell development shortly after birth. In double mutants, the homozygous staggerer mutation can 'rescue' Purkinje cells carrying a channel-opening mutation in the Glutamate receptor delta2 (Lurcher) from apoptotic death during the third and fourth postnatal weeks. Transcript levels for the glutamate receptor delta2, a channel subunit that is found at both climbing fiber and parallel fiber synapses on cerebellar Purkinje cells, are higher in the staggerer mutant cerebellum than in the wild-type cerebellum at age 14 days. By 21 days, the wild-type level is higher, having increased tremendously while the staggerer increase is modest. The results imply that the mechanism protecting Purkinje cells in staggerer-Lurcher double mutants operates by blocking mutant receptor protein localization, rather than mRNA transcription. Between the ages 10 and 14 days, the climbing fiber innervation of Purkinje cells is known to switch from multiple to single in wild-type, but not in the staggerer mutant. Therefore, the results also suggest that the multiple innervation and the level of the receptor message are coordinated, either directly or indirectly.

Molecular cloning and protein expression of EC1-2 and EC3-4 epitopes of pemphigus vulgaris antigen

OBJECTIVE

To clone and express EC1-2 and EC3-4 epitopes of PVA (pemphigus vulgaris antigen, desmoglein-3) in order to diagnose pemphigus and study the relationship between epitopes of PVA and anti-PVA antibody.

METHODS

RNA was extracted from keratinocytes and the cDNA of epitopes EC1-2 and EC3-4 was synthesized by reverse transcription. Amplified genes of EC1-2 and EC3-4 were inserted into the expression plasmid, PGEX-4T-1, and transformed into E. coli BL21 by electric transduction. Recombinant fusion proteins of EC1-2 and EC3-4 epitopes were expressed by IPTG induction. These proteins were separated on SDS-PAGE gels and electroblotted to nitrocellulose to detect the anti-PVA antibody.

RESULTS

The sequences of cloned EC1-2 and EC3-4 genes were identical to the sequence registered in PC/GENE. Expressed recombinant proteins reacted only to sera from patients with pemphigus vulgaris, not to sera from patients with bullous pemphigoid, systemic lupus erythematosus or normal persons.

CONCLUSIONS

These recombinant proteins are very specific in antigenicity. This may provide a new method for the diagnosis of pemphigus vulgaris (PV) or the differential diagnosis of other bullous cutaneous diseases via patient sera. It is also helpful in understanding the relationship between adhesion molecules and the pathogenic mechanism of pemphigus vulgaris.

Decreased luteinizing hormone receptor mRNA expression in human ovarian epithelial cancer

OBJECTIVES

The objective of this study was to examine the distribution and cellular localization of luteinizing hormone receptor (LHR) in ovarian epithelial tumors (OETs) and their presumed precursor lesions-ovarian epithelial inclusions (OEIs). The clinicopathologic correlation of the receptor expression in OET was also examined.

METHODS

Fifteen microdissected samples of ovarian surface epithelium (OSE), 20 OEIs from benign ovaries, and 141 OETs, including 48 cystadenomas, 33 borderline tumors, 60 carcinomas, and 5 metastatic cancers, were examined for LHR expression by using reverse transcription polymerase chain reaction and in situ hybridization. LHR expression in tumor epithelium and tumor stroma was analyzed separately. The clinicopathologic correlation data were analyzed by standard analysis of variance and contingency table methods.

RESULTS

LHR expression was identified in the majority of OSE and OEI samples. In OETs, LHR positivity was found in the epithelial cells in 27% of cases and in the stromal compartment in 37% of cases. LHR-positive stromal cells were mainly luteinized cells. Within the tumor epithelium, LHR expression was detected in 42% of benign, 24% of borderline, and 17% of malignant OETs. LHR expression in tumor stroma showed a similar trend of reduction from benign to malignant OETs. Within the 17 carcinomas, LHR was expressed in the epithelium in 47% of grade 1, 12% of grade 2, and only 5% of grade 3 cancers. The mean age of the LHR-positive group was younger than that of the receptor-negative patients. Compared with mucinous and other types of OETs, serous OETs showed higher LHR expression in the epithelium. Compared with the OETs removed in the different menstrual phases, OETs in the secretory phase showed higher LHR in the tumor stroma than in the proliferative phase. No receptor mRNA was detected in the epithelium of five carcinomas metastatic to the ovary. LHR transcription splicing variants from a single previous report were confirmed in this study.

CONCLUSIONS

Malignant OETs have significant reduction of LHR expression compared with precursor lesions and benign and borderline OETs. LHR expression shows a steady decline from low-grade to high-grade ovarian cancer. The presence of LHR receptor in tumor epithelium suggests that luteinizing hormone in serum may have direct influence on tumor growth, whereas the receptor in tumor stroma may be indicative of a paracrine function of LH in the development of OETs.

Enhanced prognostic stratification of patients with left ventricular hypertrophy with the use of single-photon emission computed tomography

BACKGROUND

Patients with left ventricular hypertrophy (LVH) are at increased risk of future cardiovascular events. Little is known about risk stratification of these patients with the use of myocardial perfusion imaging. This study sought to assess the prognostic stratification of patients with LVH by using myocardial perfusion single-photon emission computed tomography (SPECT).

METHODS AND RESULTS

We studied 633 consecutive patients with electrocardiographic evidence of LVH who underwent dual isotope myocardial perfusion SPECT (rest thallium 201/stress technetium 99m sestamibi) and were followed up for a mean period of 22 +/- 7 months. During the follow-up period, 67 events (35 cardiac deaths and 32 nonfatal myocardial infarctions) occurred (6% annual event rate). The results of the perfusion scan significantly risk-stratified the population; patients with normal scans had a low rate of nonfatal myocardial infarction and cardiac death (<1% per year of follow-up). The rates of cardiac events increased significantly as a function of the scan result: 4.9% in patients with mildly abnormal scans and 10. 3% in moderately to severely abnormal scans. Cox proportional hazards analysis demonstrated that after adjusting for pretest likelihood of coronary artery disease (the most predictive clinical variable; chi(2) = 15.5, P <.001), summed stress score (the most predictive nuclear variable; chi(2) = 18, P <.0001) added significant incremental prognostic information (global chi(2) increased from 15.5 to 36; P <.001).

CONCLUSIONS

In patients with LVH with an overall high cardiac event rate, SPECT provided enhanced stratification by adding significant incremental prognostic information over clinical and historic variables.

High-performance chromatofocusing using linear and concave pH gradients formed with simple buffer mixtures. II. Separation of proteins

The separation of proteins using high-performance chromatofocusing with linear or concave pH gradients formed using simple mixtures of buffering species in the elution buffer is investigated experimentally. The separation achieved is comparable to that using polyampholyte elution buffers with these types of systems. More specifically, protein band widths at one half of the band height in the range between 0.1 and 0.025 pH units were observed, and good resolution was achieved of protein variants differing by a single amino acid residue in separation times of 30 min or less. An especially useful elution buffer is investigated that contains only four buffering species and that produces a linear pH gradient in the range between pH 9.5 and 6.0 when used together with a particular high-performance column packing made specifically for chromatofocusing. This elution buffer and column packing combination is evaluated by using it for the chromatofocusing of equine myoglobin and human hemoglobin variants. Additional applications are described in which a polyethyleneimine derivatized silica column packing and a pH gradient that is concave in shape are used for the separation of proteins in an E. coli cell lysate.

High-performance chromatofocusing using linear and concave pH gradients formed with simple buffer mixtures. I. Effect of buffer composition on the gradient shape

Numerical calculations together with simplified analytical relations based on local equilibrium theory are used to determine the factors which govern the shape of the gradient formed during chromatofocusing when simple mixtures of buffering species are employed to produce linear or concave pH gradients. The numerical and analytical development is also used to determine the relation between the gradient shape and the buffering capacities of the adsorbed and liquid phases. Experiments which verify the theoretical methods are described where internally generated, retained pH gradients of various shapes are formed using high-performance chromatography columns. The resulting experimental and theoretical basis can be employed as means for the selection of the buffer composition for use in chromatofocusing.

A new algorithm for the quantitation of myocardial perfusion SPECT. II: validation and diagnostic yield

This study validates a new quantitative perfusion SPECT algorithm for the assessment of myocardial perfusion. The algorithm is not based on slices and provides fully 3-dimensional sampling and analysis independent of assumptions about the geometric shape of the left ventricle.

METHODS

Radiopharmaceutical- and sex-specific normal limits and thresholds for perfusion abnormality in 20 segments of the left ventricle were developed for separate, dual-isotope rest 201Tl-exercise 99mTc-sestamibi SPECT in 36 patients with <5% before-scanning likelihood of coronary artery disease (CAD) (group 1) and 159 patients with perfusion abnormalities (group 2). These thresholds were validated in 131 patients (group 3) by comparison with expert visual interpretation. Thresholds for automatic segmental scores were developed and validated for groups 2 and 3, respectively. The accuracy of CAD detection was assessed in 94 patients, who underwent coronary angiography (group 4).

RESULTS

Overall sensitivity for detection of stress and rest segmental perfusion abnormality was 91% and 96%, respectively, for men and 89% and 79%, respectively, for women. Overall specificity for stress and rest was 87% and 90%, respectively, for men and 88% and 90%, respectively, for women. Agreement between automatic and visual scores was good (weighted K of 0.71 and 0.60 for stress and rest images, respectively). Sensitivity and specificity were 88% for the detection of > or =70% stenosis. For the detection of left anterior descending, left circumflex, and right coronary artery stenosis, sensitivity was 84%, 86%, and 88%, respectively, and specificity was 84%, 88%, and 81%, respectively.

CONCLUSION

The new quantitative perfusion SPECT approach is highly sensitive and specific for the detection and localization of CAD, provides accurate automatic scores for the assessment of regional perfusion, and overcomes the low-specificity limitations of previous quantitative algorithms.

Comparative localization of myocardial ischemia by exercise electrocardiography and myocardial perfusion SPECT

BACKGROUND

Prior angiographic study has shown that the patterns of ST-segment depression during exercise do not provide localizing information of the responsible coronary lesion. However, little is known regarding the ability of exercise-induced ST-segment displacement to localize myocardial perfusion defects.

METHODS AND RESULTS

We studied 552 consecutive patients without prior myocardial infarction who had reversible perfusion defect in one vascular territory on rest 201Tl/exercise 99mTc-labeled sestamibi dual-isotope myocardial perfusion single photon emission computed tomography (SPECT) and ischemic ST depression or elevation during exercise. Of these, 192 patients had angiographically documented coronary artery disease (CAD). Two hundred thirty-two patients had maximal ST depression in anterior leads, 247 patients had maximal ST depression in inferior leads, and 45 patients had similar maximal ST depression in both anterior and inferior leads. Twenty-eight (5%) patients had ST elevation with absent Q waves. In patients with maximal ST depression in anterior leads, perfusion defects were found in the territory of the left anterior descending coronary artery (LAD) in 30%, in the territory of the right coronary artery (RCA) in 52%, and in the territory of the left circumflex coronary artery (LCX) in 18%. In patients with maximal ST depression in inferior leads, perfusion defects were found in RCA territory in 44%, in the LAD territory in 42%, and in the LCX territory in 14%. Compared with exercise ST depression, the less common finding of ST elevation did provide accurate localization of perfusion defects. When ST elevation was greatest in the anterior leads, 96% of patients had LAD territory defects. When ST elevation was most prominent in the inferior leads, 100% patients had RCA territory defects. Data of coronary angiograms demonstrated that myocardial perfusion SPECT correctly identified the most stenotic coronary disease for LAD (94%), LCX (72%), and RCA (75%).

CONCLUSIONS

The findings of this study indicate that the site of maximal ST-segment depression does not identify the localization of myocardial perfusion defects. However, the less common finding of exercise-induced ST-segment elevation does predict localization of myocardial ischemia.

p53 as a significant prognostic marker in endometrial carcinoma

Although several studies have reported that p53 overexpression is associated with poor survival from endometrial cancer, this relationship might be confounded by a number of possible factors. The objective of this study was to examine the prognostic role of p53 overexpression in endometrial cancer when a panel of well-selected potential confounding factors were controlled. One hundred and twenty-five endometrial cancers were examined for p53 overexpression by immunohistochemistry (IHC). Demographic and clinical data, including age at diagnosis, race, residence, tumor grade, surgical stage, and other possible confounding factors for endometrial cancer such as diabetes, family history of cancer, hypertension, hormone replacement therapy (HRT), and obesity were collected from medical charts and pathologic reports. Survival status was determined at the end of follow-up. The Kaplan-Meier method was used to derive the survival curve, while the log-rank test was used to compare curves for two or more groups of patients. The proportional hazards regression model was used to obtain maximum likelihood estimates of relative risks (RR) and their 95% confidence intervals. Compared to the p53 nonaltered group, the presence of p53 overexpression in endometrial carcinoma was related to significantly decreased patient survival. High nuclear grade and high FIGO stage were associated with poor survival. No obvious association was found between survival and study site, race, age, and other potential risk factors of endometrial cancer. Only two variables (p53 and stage) were significantly associated with poor survival in the multivariate proportional hazards analysis. Overexpression of p53 was found to be the most significant predictor of specific survival. The relative risk for p53 overexpression was 7.46 (95% CI: 4.26-13.1) and for late stage was 4.35 (95% CI: 1.91-9.92). We conclude that p53 overexpression is the most important predictor for patient survival when a panel of well-selected potential confounding factors are taken into account. Patients with endometrial cancers who have p53 overexpression have a seven-fold higher risk of dying from disease compared to those without p53 overexpression. Whether detection of p53 alteration may serve as an indicator of high-risk patients for whom more aggressive adjuvant chemotherapy may be considered needs to be explored in the future.

Incremental prognostic value of myocardial perfusion single photon emission computed tomography in patients with diabetes mellitus

BACKGROUND

Previous studies have shown that myocardial perfusion single photon emission computed tomography (SPECT) provides incremental prognostic information in the general population, but the prognostic efficacy of nuclear testing in patients with diabetes mellitus is unclear.

METHODS

We conducted a study with 1271 consecutively registered patients with diabetes and 5862 patients without diabetes with known or suspected coronary artery disease undergoing rest thallium 201/stress technetium 99m sestamibi dual-isotope myocardial perfusion SPECT with exercise or adenosine pharmacologic testing. Patients were followed up for at least 1 year. The successful follow-up rate was 92.4% for patients with diabetes and 94.0% for subjects without diabetes. The mean follow-up period was 23.7 +/- 7.7 months for the former group and 21.5 +/- 6.1 months for the latter.

RESULTS

Over the follow-up period, patients with diabetes had significantly higher rates of hard events (cardiac death or nonfatal myocardial infarction) (4.3% per year versus 2.3% per year, P <.001) and higher total event rates (hard events and late revascularization) (9.0% per year versus 5.3% per year, P <. 001) compared with rates among patients without diabetes. Cox proportional hazards analysis revealed that nuclear testing added incremental value over clinical and historical variables among patients with diabetes (global chi(2) increased 46% for the exercise group [n = 619] and 88% for the adenosine group [n = 461]; both P <. 001). The event rates rose significantly as a function of summed stress score and summed difference score among both patients with diabetes and patients without diabetes (P <.001). The patients with diabetes with normal scans had relatively low hard event rates (1% to 2% per year), those with mildly abnormal scans had intermediate hard event rates (3% to 4% per year), and those with moderately to severely abnormal scans had relatively high hard event rates (>7% per year).

CONCLUSIONS

The results of this study indicated that exercise and adenosine stress myocardial perfusion SPECT are valuable for risk stratification and management of patients with diabetes.

[A clinicopathologic study on eight cases of cystic and solid tumors of pancreas]

OBJECTIVE

To study the clinicopathologic characteristics, differentiation patterns and histogenesis of cystic and solid tumors of the pancreas (CSTP).

METHODS

8 cases of CSTP were studied using histologic (HE and PAS), immunohistochemical (S-P method) and electron microscopic techniques.

RESULTS

All the patients were adolescent and young adult females, 14-33 years in age (mean 25.3 years) without recurrence after tumor resection. The mean diameter of tumors was 9.6 cm, all encapsulated. Histological examination showed presence of solid sheets, pseudopapillary, in all of the cases. Hemorrhage, foam cells, and cholesterol crystals were often found. Immunohistochemically, 8 cases were positive for alpha(1)-AT and lysozyme; 6 cases expressed vimentin, 2 cases expressed actin, and CgA-positive cells found in the tumor cell nests in one case. All of the cases showed PR, and 4 cases showed ER positive immunoreactivity in the majority of tumor cells, but negative for CK AE1, CK AE3, EMA, Synaptophysin, ACTH, gastrin, somatostatin, insulin, and glucogan in all the cases. Electron microscopy of 3 cases showed evidences of polymorphism in differentiation of the tumor cells, including the transitional appearance into ducts, acinus, and endocrine cells. Weibel-Palade body found in tumor cells in one out of 8 cases.

CONCLUSIONS

(1) CSTP is a distinct clinicopathologic entity in young female patients with a benign clinical course. (2) CSTP develops from primitive pancreatic cells, with the potentiality of developing into ducts, acinus, and endocrine cells.

In vitro translation in a cell-free system from Trypanosoma brucei yields glycosylated and glycosylphosphatidylinositol-anchored proteins

African trypanosomes escape many cellular and unspecific immune reactions by the expression of a protective barrier formed from a repertoire of several hundred genes encoding immunologically distinct variant surface glycoproteins (VSGs). All mature VSGs are glycosylphosphatidylionositol-anchored and N-glycosylated. To study trypanosome-specific post-translational modifications of VSG, a cell-free system capable of in vitro translation, translocation into the rough endoplasmic reticulum, N-glycosylation and glycosylphosphatidylinositol-anchor addition was established using lysates of the bloodstream form of Trypanosoma brucei. Monitoring protein synthesis by [35S]methionine incorporation, labeled protein bands were readily detected by fluorography following SDS/PAGE. Appearance of these bands increased during a time-course of 45 min and was sensitive to cycloheximide but not chloramphenicol treatment. Efficiency of this system, in terms of incorporation of radiolabeled amino acids into newly formed proteins, is similar to reticulocyte lysates. The system does not, however, allow initiation of protein synthesis. Depending on the clone used, immunoprecipitation revealed one or two newly formed VSG bands. Upon digestion with N-glycosidase F these bands resulted in a single band of a lower apparent molecular mass, indicating that newly synthesized VSG underwent translocation and glycosylation in the cell-free system. Biotinylation of VSG and a combination of precipitation with immobilized avidin and detection of VSG using antibodies specific for clones and cross-reacting determinants revealed that newly formed VSG contained the glycosylphosphatidylinositol anchor.

Role of heme in structural organization of cytochrome c probed by semisynthesis

The heme prosthetic group of cytochrome c is covalently attached to the protein through thioether bonds to two cysteine side chains. The role of covalent heme attachment to cytochrome c is not understood, and most heme proteins bind the prosthetic group by iron ion ligation and tertiary interactions only. A two-armed attachment seems redundant if the role of covalent connection is to limit heme group orientation or to decouple heme affinity from redox potential. These considerations suggested that one role for covalent attachment of the rigid planar heme might be in organizing the cytochrome c protein structure. Indeed, porphyrin cytochrome c (in which the heme iron ion has been removed) is substantially more ordered than apocytochrome c, having characteristics consistent with a molten globule state. To assess the importance of planar rigidity in ordering this protein, semisynthesis was used to substitute porphyrin by two hydrophobic surrogates, one based on biphenyl and the other on phenanthrene, which have different degrees of planarity and rigidity. The expected two-armed covalent attachment of each surrogate was confirmed in the protein products by a variety of methods including mass spectrometry and NMR. Despite being only about half the size of the porphyrin macrocycle, and lacking any possibility for ligation or polar group interactions with the surrounding protein, the two surrogates confer helix contents that are comparable to that of the molten globule formed by porphyrin cytochrome c under similar solution conditions. The pH titrations of the derivatives monitored by circular dichroism exhibit reversible, bell-shaped folding and unfolding transitions, implying that charge group interactions in the protein are involved in stabilizing the helical structures formed. The thermal transitions of the two derivatives at neutral pH are cooperative, with similar midpoints. The similarity of helical content and structural stability in the two derivatives indicates that the increase in conformational freedom by the biphenyl surrogate does not substantially reduce protein structural stability. The similarity of the two derivatives to porphyrin cytochrome c suggests that the common feature among the three covalently attached groups-their hydrophobicity-is by far the dominant factor in organizing stable structures in the protein.

Effects of overlapping parametric resonances on the particle diffusion process

The evolution of the beam distribution in a double-rf system with a phase modulation on either the primary or secondary rf cavity was measured. We find that the particle diffusion process obeys the Einstein relation if the phase space becomes globally chaotic. When dominant parametric resonances still exist in the phase space, particles stream along the separatrices of the dominant resonance, and the beam width exhibits characteristic oscillatory structure. The particle-tracking simulations for the double-rf system are employed to reveal the essential diffusion mechanism. Coherent octupolar motion has been observed in the bunch beam excitation. The evolution of the longitudinal phase space in the octupole mode is displayed.

Strand interruptions confer strand preference during intracellular correction of a plasmid-borne mismatch in Saccharomyces cerevisiae

Site-directed mutagenesis was used to construct yeast centromere plasmids in which a strand nick or gap could be placed 5' or 3', on either strand, to a reporter gene (SUP4-o) carrying defined base mismatches. The plasmids were then transformed into yeast cells and the direction and efficiency of mismatch repair were assayed by scoring colouring of the transformant colonies. Strands that were nicked were consistently corrected more often than intact strands, but the effect was very small. However, placement of a small gap at the same positions as the nicks resulted in a marked increase in selection for the gapped strand and an enhanced efficiency of mismatch repair. Both the preference for the gapped strand and correction of the mismatch were offset by deletion of the mismatch repair gene PMS1. Together, the results suggest that strand interruptions can direct intracellular mismatch correction of plasmid-borne base mispairs in yeast.

Comparative ability of myocardial perfusion single-photon emission computed tomography to detect coronary artery disease in patients with and without diabetes mellitus

BACKGROUND

Diabetics generally have more frequent and extensive silent myocardial ischemia than nondiabetics, increasing the importance of noninvasive detection of coronary artery disease (CAD) in this cohort. However, little is known regarding the diagnostic accuracy of myocardial perfusion single-photon emission computed tomography (SPECT) in patients with diabetes. This study was undertaken to compare the diagnostic value of rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion SPECT in patients with and without diabetes.

METHODS

Of the 203 patients with diabetes and 260 patients without diabetes who underwent dual-isotope myocardial perfusion SPECT with exercise or pharmacologic stress testing, 138 diabetics (12% type 1 diabetics) and 188 nondiabetics had coronary angiography within 6 months of the nuclear test, and 65 diabetics and 72 nondiabetics had a low likelihood (<10%, mean 6% +/- 3% and 6% +/- 3%) of CAD.

RESULTS

The angiographic data showed that patients with diabetes had less incidence of 1-vessel disease and a higher incidence of 3-vessel/left main artery disease than patients without diabetes (P <.05). The overall sensitivity and specificity, respectively, of SPECT for detecting CAD with the criterion of >/=50% diameter stenosis were 86% (95 of 111) and 56% (15 of 27) in diabetics, 86% (122 of 142) and 46% (21 of 46) in nondiabetics (P = not significant). With the criterion of >/=70% diameter stenosis the corresponding results were 90% (86 of 96) and 50% (21 of 42) in diabetics, and 91% (108 of 119) and 43% (30 of 69) in nondiabetics, respectively (P = not significant). The normalcy rate for low likelihood patients was 89% (58 of 65) in diabetics and 90% (65 of 72) in nondiabetics (P = not significant). The sensitivity and specificity for individual vessel detection were also similar in patients with and without diabetes (P = not significant) except for a lower sensitivity and a higher specificity for detecting left anterior descending coronary artery disease in the diabetic group (P <.05).

CONCLUSION

Dual-isotope myocardial perfusion SPECT has comparable accuracy for the diagnosis of CAD in diabetic and nondiabetic patients.

[Direct, rapid detection for rifampin susceptibility to M. tuberculosis]

OBJECTIVE

To evaluate the use of molecular biotechnology for direct, rapid detection of rifampicin-resistance mutations in M. tuberculosis.

METHODS

45 M. tuberculosis clinical isolates and 70 sputum samples were tested by polymerase chain reaction-single stranded conformation polymorphism (PCR-SSCP) technique. M. tuberculosis strain H37Rv was used as control and compared with the result of susceptibility test. DNA sequencing was also performed in some of the strains.

RESULTS

All tested susceptible isolates displayed identical SSCP patterns. Of 29 RFP resistance strains, 26(90%) had distinct mobility shifts that can be discriminated from susceptible isolates. 9 sputum samples which were succeasfully evaluated by PCR-SSCP showed concordant result acquired from BACTEC 460 method. As the result of DNA sequencing, it was observed that seven RFP-resistance phenotype of M. tuberculosis strains had missense mutation, in which 5 isolates displayed TCG-->TTG or CAG mutations at codon 531.2 had CAC-->TAC mutation at codon 526. On the other hand, one strain which was susceptible to rifampin exhibited identical nucleotide alignment to the sequence of rpoB gene.

CONCLUSIONS

PCR-SSCP could be used as a method for simple, rapid, and reliable detection of rifampicin-resistance mutations in clinical samples of M. tuberculosis.

Structural organization in peptide fragments of cytochrome c by heme binding

Prosthetic groups are often important structural organizers of proteins as well as essential functional components. Insertion of prosthetic groups is usually spontaneous, and implies an apoprotein that is partially preorganized to provide a recognition surface for specific binding. Cytochrome c is distinguished by having its heme attached by a dedicated heme lyase through thioether links to cysteine side-chains, and the apoprotein shows no evidence of preorganization under physiological conditions. Nevertheless, addition of heme to two short fragments of cytochrome c enhances helical structure substantially (from approximately 8% to approximately 22%), an effect that depends on iron ligation but not thioether linkage. The helical segments in the corresponding parts of the native holoprotein have little contact surface with heme, implying that the increased helical structure in the fragment complex may depend on tertiary interactions. The absence of the intervening polypeptide chain suggests that the complex represents a relatively independent folded subdomain.

Identification of new melanoma epitopes on melanosomal proteins recognized by tumor infiltrating T lymphocytes restricted by HLA-A1, -A2, and -A3 alleles

To isolate melanoma Ags recognized by T cells, cDNA libraries made from melanoma cell lines were screened with four CTLs derived from tumor infiltrating lymphocytes (TIL) that were able to recognize melanoma cells in a HLA-A1, -A2, or -A3 restricted manner. Although cDNAs encoding the previously identified melanoma Ags, tyrosinase and gp100, were isolated, these TIL were found to recognize previously unidentified peptides. An HLA-A1-restricted CTL, TIL1388, was found to recognize a tyrosinase peptide (SSDYVIPIGTY), and an HLA-A3-restricted CTL, TIL1351, recognized a gp100 peptide (LIYRRRLMK). CTL clones isolated from the HLA-A2-restricted TIL1383 recognized a gp100 peptide (RLMKQDFSV). HLA-A2-restricted CTL, TIL1200, recognized a gp100 peptide (RLPRIFCSC). Replacement of either cysteine residue with alpha-amino butyric acid in the gp100 peptide, RLPRIFCSC, enhanced CTL recognition, suggesting that the peptide epitope naturally presented on the tumor cell surface may contain reduced cysteine residues. Oxidation of these cysteines might have occurred during the course of the synthesis or pulsing of the peptide in culture. These modifications may have important implications for the development of efficient peptide-based vaccines. These newly identified peptide epitopes can extend the ability to perform immunotherapy using synthetic peptides to a broader population of patients, especially those expressing HLA-A1 or HLA-A3 for whom only a few melanoma epitopes have previously been identified.

Comparative prognostic value of automatic quantitative analysis versus semiquantitative visual analysis of exercise myocardial perfusion single-photon emission computed tomography

OBJECTIVES

The purpose of this study was to determine the prognostic value of automatic quantitative analysis in exercise dual-isotope myocardial perfusion single-photon emission computed tomography (SPECT) and to compare the prognostic value of quantitative analysis to semiquantitative visual SPECT analysis.

BACKGROUND

Extent, severity and reversibility of exercise myocardial perfusion defects have been shown to correlate with prognosis. However, most studies examining the prognostic value of SPECT in chronic coronary artery disease (CAD) have been based on visual analysis by experts.

METHODS

We studied 1,043 consecutive patients with known or suspected CAD who underwent rest Tl-201/exercise Tc-99m sestamibi dual-isotope myocardial perfusion SPECT and were followed up for at least 1 year (mean 20.0+/-3.7 months). After censoring 59 patients with early coronary artery bypass grafting or percutaneous transluminal coronary angioplasty, <60 days after nuclear testing, the final population consisted of 984 patients (36% women, mean age 63+/-12 years).

RESULTS

During the follow-up period, 28 hard events (14 cardiac deaths, 14 nonfatal myocardial infarctions) occurred. Patients with higher defect extent (>10%), severity (>150) and reversibility (>5%) by quantitative SPECT defect analysis, as well as those with an abnormal scan (>2 abnormal segments, summed stress score >4 and summed difference score >2) by semiquantitative visual SPECT analysis, had a significantly higher hard event rate compared to patients with a normal scan (p < 0.001). With both visual and quantitative analyses, hard event rates of approximately 1% with normal scans and 5% with abnormal scans (p > 0.05) were observed over the 20-month follow-up period. A Cox proportional hazards regression model showed that chi-square increased similarly with the addition of quantitative defect extent and visual summed stress score variables after considering both clinical and exercise variables (improvement chi-square = 11 for both, p < 0.0007). There were no significant differences in the areas under receiver operating characteristic curves between quantitative and visual analysis (p > 0.70). Linear regression analysis also indicated that quantitative assessments correlated well with visual semiquantitative assessments.

CONCLUSIONS

The findings of this study indicate that automatic quantitative analysis of exercise stress myocardial perfusion SPECT is similar to semiquantitative expert visual analysis for prognostic stratification. These findings may be of particular clinical importance in laboratories with less experienced visual interpreters.

Exercise tolerance in asymptomatic elderly men with fluoroscopically detected coronary artery calcification

STUDY OBJECTIVE

The value of detecting coronary artery calcification (CAC), by cardiac imaging, for the diagnosis of coronary artery disease (CAD) in asymptomatic middle-aged men has been demonstrated. However, the incidence of CAC increases with age. The functional significance of CAC remains unknown in asymptomatic elderly men. The purpose of this study is to explore whether CAC in asymptomatic aging men signifies the presence of cardiovascular dysfunction during exercise.

DESIGN

This study was designed to address whether elderly asymptomatic men, selected because they have CAC, have reduced exercise tolerance due to functionally significant CAD.

PARTICIPANTS AND SETTING

Thirty-eight asymptomatic male volunteers (ages 50 to 75 years, mean [+/-SD] 64+/-7 years) with a normal resting ECG and at least one coronary risk factor, in a population study. Nineteen subjects had CAC detected by digital subtraction fluoroscopy in at least two major coronary arteries, and 19 subjects had no identifiable CAC.

METHODS AND RESULTS

Each subject underwent a symptom-limited incremental exercise test with 12-lead ECG monitoring and respiratory gas analysis. Four indexes of exercise oxygen transport were evaluated: peak oxygen uptake (VO2), lactic acidosis threshold, peak VO2/heart rate ratio, and VO2 relative to a work rate increase. Eleven of 38 subjects (28%) were found to have reduced oxygen transport, which was defined as an abnormal reduction in more than two of the above four indexes of oxygen transport. Five of the 11 subjects with reduced oxygen transport had CAC, and 6 subjects did not (not significant). Only one subject with CAC had exercise ST depression.

CONCLUSION

Significant CAC in asymptomatic men over age 50 does not signify exercise limitation due to CAD.

[The development of a new laryngoscope]

A new type of laryngoscope, with powerful cold beam and fiber optic bundle, has been developed. It is a reliable aid of intubates during the field of emergency treatment and the foging anaesthesia can be done at the same time. The waterproof handle can be immersed in special liquids for thorough, effective cleaning and sterilization.

[Detection and identification of the DNA between Mycobacterium tuberculosis and Mycobacterium nontuberculosis by triplex polymerase chain reaction technique]

OBJECTIVE

To improve the specificity and sensitivity of polymerase chain reaction (PCR) technique for detecting and identification of DNA of M. tuberculosis and M. nontuberculosis.

METHOD

Three pairs of oligonucleotide primer were used in triplex-PCR. A 383 bp DNA fragment encoding part of the 65,000 mycobacterial surface antigen, a 123 bp fragment corresponding to a specific M. tuberculosis complex sequence which was the insertion sequence 6110 (IS 6110) and a 268 bp fragment for human beta-globin were amplified by triplex-PCR respectively.

RESULT

The sensitivity of the triplex-PCR-electrophoresis for the DNA of mycobacterium was 0.6 pg. The specific bands of 383 bp and 123 bp among the amplified DNA from M. hominis, M. bovis, BCG and M. simiae were present in the agarose gel. By contrast, only a band of 383 bp was found among the M. nontuberculosis which contained M. avium, M. chelonae, M. scrofulaceum, M. xenopi, M. kansasii, M. intracellulare and M. smegmatis. Compared with the standard strains, there was an additional 268 bp band in simulated clinical samples infected by Mycobacterium. The above 3 specific bands were found neither in other 15 bacterial species tested nor in Mycoplasma pneumoniae. 182 clinical samples were examined by culture, smear and triplex-PCR. 72 nontuberculous clinical samples were all negative. In 110 tuberculosis clinical samples, the positive rates were 2.7%, 13.6% and 32.7%, respectively.

CONCLUSION

The triplex-PCR possesses a high specificity and sensitivity. This method could detect and identify the DNA of M. tuberculosis and M. nontuberculosis except M. simiae. It is a valuable tool for early diagnosis and differentiation for infection of M. tuberculosis and M. nontuberculosis.

[Determination enzyme protein of CK-MB m-AST and ChE by immunological methods and survey of its applying values]

In recent decades, because considerable progress has been made due to rapid developments in basic theory and techniques in molecular biology and immunology, the determination of trace enzyme proteins is not difficult. We measured the serum concentration of Creatine kinase-MB (CK-MB) mitochondria aspartate aminotransferase (m-AST) and cholinesterase (ChE) immunologically and compared these findings with those of an assay of enzyme activity. Purification of enzyme protein and preparation of serum antibodies monoclonal antibodies established the immunological assay methods. Equipment and reagents for enzyme activity test use 7150 Biochemical Analyzer. CK-NAC AST and ChE were produced by trace kits (Australia). CK-MB and m-AST use immunological inhibition method. CK-MB m-AST ChE of protein determination used immunological turbidimetry. The normal group included 150 cases and the 1990 patient group. Results of the two methods did not significantly differ for normal controls, but were significantly different in the patient group. These results demonstrated that the two methods differ, although each may have specific clinical significance. How to evaluate these differences needs to be studied further, but immunological assay uses higher values for clinical diagnosis than enzyme activity assay.

The use of melanosomal proteins in the immunotherapy of melanoma

Clinical observations in the interleukin (IL) 2-based immunotherapies suggest that T cells play a central role in the rejection of melanoma. Using cDNA expression cloning, we have isolated genes encoding melanoma antigens recognized by tumor-infiltrating T lymphocytes. These antigens are categorized as (a) melanocyte-specific melanosomal proteins (MART-1/melan A, gp100, tyrosinase, TRP-1, and TRP-2), (b) tumor-specific mutated proteins (beta-catenin), and (c) others (p15). A variety of mechanisms has been identified for the generation of T cell epitopes on tumor cells. Some of the HLA-A2 binding epitopes from the melanosomal antigens appear to be subdominant self-determinants with relatively low major histocompatibility complex binding affinity. The effectiveness of adoptive transfer into patients of cytotoxic T lymphocytes recognizing the melanosomal antigens, the significant correlation between vitiligo development and clinical response in patients receiving IL-2-based immunotherapies, and the sporadic tumor regressions observed in some patients following immunization with the MART-1 or gp100 peptides in incomplete Freund's adjuvant or recombinant viruses expressing the MART-1 antigen suggest that these epitopes may represent tumor rejection antigens. Phase I immunization trials using peptides or recombinant viruses containing genes encoding the melanosomal antigens MART-1 or gp100, with or without co-administration of cytokines such as IL-2, IL-12, or granulocyte-macrophage colony-stimulating factor, are being conducted in the Surgery Branch of the National Cancer Institute. These studies may demonstrate the feasibility of using melanosomal proteins for the immunotherapy of patients with melanoma.

Study on the transmission threshold value of bancroftian filariasis

OBJECTIVE

To elucidate the transmission dynamic and epidemic trend of bancroftian filariasis occurred under the condition with no control measure taken 5 years after elimination of filariasis.

METHODS

A 10-year longitudinal observation (from 1984 to 1994) was made in Huayuan Village in Shengli Township of Tancheng County, which used to be a high bancroftian filariasis-endemic area in southern part of Shandong Province.

RESULTS

The microfilarial rate decreased from 0.56% before the study to 0.12% after the study and 8 out of the 9 previous microfilaria-positive cases became negative gradually. During the study period, 6 new microfilaremia cases were detected, 5 of which became negative naturally within 3 to 4 years. Eighty-eight point eight nine per cent of the detected patients with microfilaremia converted into IgG4-negative after 10 years. The natural infective rate of vectors decreased year by year and became zero by the tenth year of the study, the annual transmission potency decreased also from 3.47 to zero by the tenth year.

CONCLUSIONS

It showed that under the local natural environment the biting rate representing the vector density which was obtained by capture method was from 24.1 to 52.5 person/night among the residents who did not use mosquito nets, and 13.5 to 21 person/night among the residents who used mosquito nets. The microfilarial rate of 0.56% in population with the average microfilarial density of 6.6 to 20.7 capita/60 microliters ear blood of residual microfilaria-positive patients might be considered as the terminal threshold of transmission.

Sequence of a 131-kb region of 5q13.1 containing the spinal muscular atrophy candidate genes SMN and NAIP

The spinal muscular atrophies (SMA), which are characterized by motor neuron loss and progressive paralysis, are among the most common autosomal recessive disorders. The SMA region of chromosome 5q13.1 is distinguished by variable amplification of genomic sequence incorporating a number of genes and pseudogenes. Recently, two SMA candidate genes mapping to this area were identified: survival motor neuron (SMN) and neuronal apoptosis inhibitory protein (NAIP). The telomeric copy of SMN (SMNtel) is deleted in over 95% of cases of SMA, with NAIP deletions primarily seen in type I SMA. We present here 131 kb of genomic sequence from 5q13.1 incorporating both NAIP and SMNtel in addition to revisions of the original NAIP cDNA sequence. The Alu-rich NAIP-SMNtel interval contains the microsatellite polymorphisms that are deleted in as many as 80% of type I SMA chromosomes, focusing attention on this region in the pathogenesis of type I SMA.