Hepatoma Derived Growth Factor (HDGF) Targeting as a Therapeutic Approach for Radio-Naive and Radioresistant Hepatocellular Carcinoma

PURPOSE/OBJECTIVE(S)

The role of radiotherapy in treating hepatocellular carcinoma (HCC) has gained importance. Hepatoma-derived growth factor (HDGF) is a nuclear growth factor involved in the development of HCC and its overexpression has been linked to tumor progression and radiation treatment failure. The aim of this study is to investigate the potential therapeutic benefits of HDGF-targeting treatment in combination with or without radiation for both radio-naive and radioresistant HCC cells.

MATERIALS/METHODS

A series of radiation doses (2Gy, 4Gy, 8Gy, 12Gy, and 20Gy in one fraction) were administered to Huh7 human HCC cells. The gene expression profiles of radiation-treated Huh7 cells were analyzed. The radioresistant Huh7 cell line (Huh7-IR) was established by repeatedly irradiating with 2-week intervals with 8 Gy of X-ray to a total dose of 80 Gy. After acquiring radioresistance, the expression levels of HDGF, cancer stem cell (CSC) markers, and epithelial-mesenchymal transition (EMT) factors were validated. The pShuttle-shHDGF plasmid with adenovirus vector was generated for HDGF targeting treatment (HDGF knockdown). The effect of the HDGF targeting treatment on tumorigenic processes and cell cycle distribution in the radio-naive and radioresistant cells with or without irradiation were explored.

RESULTS

After radiation treatment, qPCR analysis showed that the mRNA expression of HDGF, CSC markers (CD133, CD44, and ABCG2), and EMT markers (TWIST and SNAIL) increased over time, with the most significant upregulation observed between 48-72 hours. In the radioresistant Huh7-IR cells, HDGF, CSC markers (CD133 and CD44), and the EMT transcriptional factor (TWIST) were significantly higher than in the parental Huh7 cells. The Huh7-IR cells also showed a significant arrest in the G0/G1 phase. X-ray radiation alone significantly reduced cell proliferation and invasion in the Huh7 cells compared to the control group. The HDGF targeting treatment significantly enhanced the X-ray-mediated inhibition of colony formation and cell invasion in both the Huh7 and Huh7-IR cells. Targeting HDGF leads to cell cycle arrest (G2/M phase) in Huh7 and Huh7-IR cells. The HDGF targeting treatment in combination with X-ray irradiation results in extensive G2/M phase arrest.

CONCLUSION

These results indicate the crucial role of HDGF in radiation therapy for radio-naive and radioresistant HCC cells. Targeting HDGF effectively suppressed colony formation and invasion, and enhanced cell cycle arrest in the G2/M phase in combination with radiation. HDGF may serve as a promising therapeutic target for improving HCC management strategies. Further investigation is required to fully comprehend the role of HDGF in improving radiation therapy efficacy for HCC.

Optimizing Radiation Therapy for Brain Metastasis Patients: A Comparative Study of Knowledge-Based Treatment Planning with HyperArc

PURPOSE/OBJECTIVE(S)

The purpose of this study is to examine the benefits of using a knowledge-based treatment planning (KBP) model in treating brain metastasis patients with HyperArc (HA) automated non-coplanar stereotactic radiosurgery (SRS).

MATERIALS/METHODS

Treatment plans of the 113 patients with either single or multiple brain metastases treated with HA were enrolled in the study. The eighty-two treatment plans with 190 metastatic brain lesions were used to construct the training model using the DVH estimation algorithm. The model was then validated on the remaining 31 patients' treatment plans with 56 metastatic brain lesions. Two corresponding HA plans were manually generated for these 31 patients using the two optimization algorithms (SRS NTO and ALDO). The SRS NTO plan generates a rapid dose falloff and prevents dose bridging of adjacent disparate targets, while the ALDO plan can cover the target with the prescribed dose but may create a high inhomogeneous dose within the target. The dosimetric outcomes were compared between the KBP, SRS NTO, and ALDO plans.

RESULTS

The KBP, SRS NTO, and ALDO plan consistently showed CTV and PTV coverage levels of over 99%. The KBP plans resulted in similar doses to the organs at risk compared to the SRS NTO plans, but significantly reduced doses to the brainstem and optic apparatus (lens, eyes, optic nerves, and optic chiasma) by 17% to 67% compared to the ALDO plans (P = 0.003 for brainstem and P < 0.001 for optic apparatus). The mean brain dose was not significantly different between the three plans (P = 0.694 for KBP vs. SRS NTO and P = 0.381 for KBP vs. ALDO). However, the ALDO plans showed a statistically better brain V12 Gy than the KBP plans (P = 0.009), with a difference of less than 2 c.c. that was deemed not clinically significant. The ALDO plans also had a significantly better intermediate dose spillage, gradient radius, and conformity index than the KBP plans. The KBP plans showed a significantly faster gradient index and intermediate dose spillage compared to the SRS NTO plans.

CONCLUSION

This study demonstrates the ability of the KBP model (RapidPlan) to generate accurate DVH predictions for use with HA in generating SRS plans that achieve optimal sparing of organs at risk while maintaining dose falloff. The KBP plans showed balanced dosimetric results compared to the SRS NTO and ALDO optimization algorithms.

Pharmacokinetics/pharmacodynamics of antipseudomonal bacteriophage therapy in rats: a proof-of-concept study

OBJECTIVES

Pan-drug-resistant (PDR) Pseudomonas aeruginosa is one of the three top-priority pathogens identified by the WHO, and bacteriophages have been investigated as an alternative therapy. However, knowledge on the pharmacokinetics/pharmacodynamics (PK/PD) of phage therapy is sparse, limiting its clinical applications. This study aimed to evaluate the PK/PD of the antipseudomonal phage øPEV20 in vivo following intravenous administration.

METHODS

Healthy Sprague-Dawley rats were given øPEV20 as a single intravenous bolus of ~6, 9 and 11-log₁₀PFU/rat. Arterial blood was sampled over 72 h. At 72 h, the animals were killed and multiple tissues were harvested for biodistribution studies. A PK model was developed using the importance sampling algorithm and deterministic simulations with a PD model were performed.

RESULTS

A three-compartment model with non-linear clearance described the exposure of øPEV20 in blood. Model evaluation indicated that the model was robust and parameter estimates were accurate. The median (standard error) values of model-predicted PK parameters for V_C, V_P1, V_P2, Q₁, Q₂, V_m and K_m were 111 mL/rat (8.5%), 128 mL/rat (4.97%), 180 mL/rat (4.59%), 30.4 mL/h/rat (19.2%), 538 mL/h/rat (4.97%), 4.39 × 10¹⁰ PFU/h/rat (10.2%) and 1.64 × 10⁷ PFU/mL/rat (3.6%), respectively. The distribution of øPEV20 was not homogeneous; there was preferential accumulation in the liver and spleen. Deterministic simulations with a PD model confirmed the importance of the host immune system in facilitating phage-mediated bacterial elimination.

CONCLUSIONS

We developed a robust PK model to describe the disposition of phages in healthy rats. This model may have significant potential in facilitating future preclinical and clinical PK/PD investigations.

First Report of Cucumber mosaic virus in Desert Rose in Taiwan

Desert rose (Adenium obesum (Forssk.) Roem. & Schult, family Apocynaceae) is native to southeastern Africa, and is a perennial potted ornamental with colorful flowers that are popular in Taiwan. Symptoms of mosaic and chlorotic ringspots and line patterns on leaves were observed in July 2010, on all eight plants in a private garden in Potzu, Chiayi, Taiwan. Spherical virus particles with a diameter of approximately 28 nm were observed in crude sap prepared from symptomatic leaves. Virus culture was established by successive local lesion isolation in Chenopodium quinoa and was maintained in the systemic host Nicotiana tabacum van Hicks. The virus was mechanically transmissible to indicator plants and induced symptoms similar to those incited by Cucumber mosaic virus (CMV). Observed symptoms included local lesions on inoculated leaves of C. amaranticolor and systemic mosaic in Cucumis sativus, Lycopersicon esculentum, N. benthamiana, N. glutinosa, and N. rustica. On N. tabacum, necrotic ringspots developed on inoculated leaves followed by systemic mosaic. Serological tests using ELISA assays and western blotting indicated that the virus reacted positively to a rabbit antiserum prepared to CMV (4). Amplicons of an expected size (1.1 kb) were obtained in reverse transcription-PCR with primers specific to the 3'-half of CMV RNA 3 (3) using total RNA extracted from infected desert rose and N. tabacum. The amplified cDNA fragment was cloned and sequenced (GenBank Accession No. AB667971). Nucleotide sequences of the coat protein open reading frame (CP ORF) (657 nt) had 92 to 96% and 76 to 77% sequence identity to those of CMV in subgroups I (GenBank Accession Nos. NC_001440, D00385, M57602, D28780, and AB008777) and II (GenBank Accession Nos. L15336, AF127976, AF198103, and M21464), respectively. Desert roses infected by Tomato spotted wilt virus (TSWV) (1) and CMV (2) have been reported previously. In spite of the plants showing mosaic symptoms similar to that caused by CMV (2) and chlorotic ringspots and line patterns caused by TSWV (1), only CMV was detected in and isolated from these infected desert roses. However, the possibility of mixed infection of CMV and other viruses were not excluded in this research. To our knowledge, this is the first report of CMV infection in desert rose plants occurring in Taiwan. References: (1) S. Adkins and C. A. Baker. Plant Dis. 89:526, 2005. (2) C. A. Baker et al. Plant Dis. 87:1007, 2003. (3) Y. K. Chen et al. Arch. Virol. 146:1631, 2001. (4) Y. K. Chen and C. C. Yang. Plant Dis. 89:529, 2005.

Crumpling wires in two dimensions

An energy-minimal simulation is proposed to study the patterns and mechanical properties of elastically crumpled wires in two dimensions. Our aim is to describe the behavior at the intermediate occupancy of the cavity so that its radius of gyration is varied up to one twentieth of the wire length. We tuned the bending rigidity and stretching modulus to measure the energy allocation, size-mass exponent, and the stiffness exponent. The mass exponent is shown to be constant at value D_{M}=1.33 , so is the stiffness exponent alpha=-0.25 . But the latter varies with the plasticity parameters s and theta_{p} . These numerical findings agree excellently with the experimental results.

NUP98-HOX translocations lead to myelodysplastic syndrome in mice and men

The myelodysplastic syndromes (MDS) are a group of clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis, peripheral blood cytopenias, dysplasia, and a propensity for transformation to acute myeloid leukemia (AML). A wide spectrum of genetic aberrations has been associated with MDS, including chromosomal translocations involving the NUP98 gene, most commonly leading to fusions of NUP98 with abd-b group HOX genes, including HOXD13. We used vav regulatory elements to direct expression of a NUP98-HOXD13 (NHD13) fusion gene in hematopoietic tissues. NHD13 transgenic mice faithfully recapitulate all the key features of MDS, including peripheral blood cytopenias, bone marrow dysplasia and apoptosis, and transformation to acute leukemia. The MDS that develops in NHD13 transgenic mice is highly lethal; within 14 months, 90% of the mice died of either leukemic transformation or severe anemia and leukopenia due to progressive MDS. These mice provide a preclinical model that can be used for the evaluation of MDS therapy and biology.

N-glycosylation and residues Asn805 and Asn890 are involved in the functional properties of type VI adenylyl cyclase

In this study, we demonstrate that type VI adenylyl cyclase (ACVI) is glycosylated in vivo. Treating HEK293 cells expressing ACVI with tunicamycin to block the addition of N-linked oligosaccharide or removing the N-linked oligosaccharide by in vitro peptidyl-N-glycosidase F digestion reduced the molecular mass of ACVI. Furthermore, tunicamycin treatment suppressed the forskolin-stimulated activity of ACVI. Mutation of either one or both potential N-glycosylation sites (Asn(805) and Asn(890), located on extracellular loops 5 and 6, respectively) also reduced the molecular mass of ACVI. Therefore, ACVI was glycosylated at both Asn(805) and Asn(890). Confocal analysis indicated that glycosylation was not required for the delivery of ACVI to the cell surface. Although no significant alterations in K(m) values for ATP or sensitivity to divalent cations were detected, the glycosylation-deficient ACVI mutant N805Q/N890Q-ACVI exhibited much lower forskolin-, Mn(2+)-, and Mg(2+)-stimulated cyclase activities than did wild-type ACVI. By contrast, the Galpha(s)-stimulated cyclase activities of wild-type ACVI and N805Q/N890Q-ACVI were indistinguishable. Furthermore, compared with wild-type ACVI, N805Q/N890Q-ACVI was less sensitive to inhibition mediated by dopamine D2 receptors or by protein kinase C. Collectively, glycosylation of ACVI not only affected its catalytic activity in an activator-dependent manner, but also altered its ability to be regulated by a Galpha(i) protein-coupled receptor or by protein kinase C.

[Hematopoietic stem cell transplantation with busulfanthiotepa-cyclophosphamide conditioning for pediatric patients with high-risk acute lymphoblastic leukemia]

Twelve children with high-risk acute lymphoblastic leukemia underwent stem cell transplantation (SCT) with a conditioning regimen consisting of busulfan, cyclophosphamide and thiotepa. Eight of them underwent SCT while in complete remission (CR) and the other 4 while not in CR. Three children underwent HLA-matched related bone marrow transplantation (BMT), 7 HLA-matched unrelated BMT, 1 HLA one-locus-mismatched unrelated cord blood cell transplantation, and 1 autologous peripheral blood stem cell transplantation. Grade II-IV acute GVHD was observed in 3 of the 11 allo-SCT cases, while chronic GVHD was seen in 3 of 9 evaluable cases. None of the 12 cases showed thrombotic microangiopathy, and veno-occlusive disease (VOD) was observed in 3. Nine of the patients are alive and disease-free 6-45 months after diagnosis. The event-free survival rate at 3 years was 72.2% for the 12 patients, including 8 of the 9 who received SCT during CR, and 2 of the 4 who did so while not in CR. The other 3 patients died: 2 of disease progression and 1 of VOD with pneumonia. All of those who died had undergone unrelated BMT.

Preparation and use of specific antibodies to the beta-I and beta-II subunits of gonadotropic hormone from Fundulus heteroclitus pituitary

Fundulus heteroclitus naturally spawns with a semilunar periodicity throughout most of the year in its southernmost habitat, an activity that can be maintained in the laboratory. The alpha and two beta subunits comprising F. heteroclitus gonadotropic hormones (GtHs) I and II have been sequenced, and antibodies have been raised against unique peptides found in each of the two beta subunits. On immunoblots of pituitary proteins, each antibody recognizes a single band with a molecular mass of 16-17 kDa, somewhat larger than the deduced sizes (11-13 kDa) of the unglycosylated subunits. Each antibody also recognizes a different subset of pituitary cells in the central (GtH I) and peripheral (GtH II) proximal pars distalis, regions that display the typical tinctorial properties of gonadotrops. The distribution and distinct separation of cells containing GtH beta subunits I and II thus differ from those found for previously described teleost species, most of which are salmonids that engage in a single spawning episode during the year. The availability of these antibodies thus makes F. heteroclitus an inexpensive, easily manipulated model system for studies on the hormonal regulation of fractional spawning common to a large class of commercially important species other than salmonids.

Cutaneous nerve terminal degeneration in painful mononeuropathy

Nociceptive nerves innervate the skin and play an important role in the generation of neuropathic pain. However, it remains elusive whether and how nociceptive nerve terminals degenerate in neuropathic pain conditions. To address this issue, we investigated cutaneous innervation in a model of painful mononeuropathy, the chronic constriction injury (CCI). The hind paws of rats were immunocytochemically stained with a pan-axonal marker, protein gene product 9.5 (PGP 9.5). Within 2 days after CCI, rats exhibited thermal hyperalgesia, and there was a partial depletion of epidermal nerves. The extent of reduction in epidermal nerves after CCI was variable with an epidermal nerve density of 3.65 +/- 1.97 fibers/mm (compared to 15.39 +/- 1.58 fibers/mm on the control side, P < 0.02). There was a mild but concomitant increase in PGP 9.5 (+) Langerhans cells in the epidermis of the skin with CCI (10.19 +/- 1.99 vs 7.75 +/- 1.36 cells/mm, P < 0.05). In the skin denervated by tight ligation of the sciatic nerve, epidermal nerves were completely depleted (0 fibers/mm vs. 12.26 +/- 1.44 fibers/mm on the control side, P < 0.001). Animals with tight ligation of the sciatic nerve exhibited thermal anesthesia. These findings suggest that the epidermis is partially denervated in CCI, and that a partial injury of nerves is correlated with the development of neuropathic pain.

Repetitious appearance and disappearance of different kinds of clonal cytogenetic abnormalities after allogeneic bone marrow transplantation

We report a childhood case that showed the repeated appearance and disappearance of various kinds of cytogenetic abnormalities (CA) for 5.5 years after allogeneic bone marrow transplantation (BMT). The patient underwent allogeneic BMT from an HLA-matched unrelated donor during the second complete remission of acute lymphoblastic leukemia. The conditioning regimen for BMT consisted of etoposide, cyclophosphamide, anti-human thymocyte immunoglobulin, and total body irradiation. There were no leukemic relapses or secondary acute myeloid leukemia/myelodysplastic syndrome (AML/MDS) since the BMT. The CA occurred from residual recipient cells, which were damaged by chemotherapy or radiation prior to BMT. Although previous studies about post-BMT CA had reported the continuous emergence of identical clones, the present case showed the appearance of one different type of clone after another. Although the appearance of different types of CA may mean that these clones did not obtain any growth advantages, it may be a sign of genomic instability, which is probably a risk factor for the development of secondary AML/MDS.

Deletion mapping of chromosome 16q24 in hepatocellular carcinoma in Taiwan and mutational analysis of the 17-beta-HSD gene localized to the region

Human chromosome band 16q24 commonly undergoes loss of heterozygosity (LOH) in human hepatocellular carcinoma (HCC). To further localize the region of deletion on 16q24 and to evaluate the genetic role of 17-beta-HSD, which is near 16q24, in HCC, we examined the pattern of loss of heterozygosity in 88 HCC patients. DNAs from 88 pairs of HCCs and corresponding non-tumor parts were prepared. Loss of heterozygosity on chromosomes 16q24 was investigated by 11 sets of microsatellite markers. Mutation analysis of type II 17-beta-HSD was performed by automatic sequencing. LOH on 16q24 for at least 1 locus was found in 43 of the 88 tumor DNAs (49%). Three non-overlapping regions of frequent LOH were defined in these 43 tumors with partial deletions. The first region was between D16S516 loci and D16S507, encompassed by a 1-cM region, defined by the D16S504. The second region was defined by the 17HSDB2 locus between D16S505 and D16S422, encompassed approximately by a 1-cM region. The third region was between D16S520 and D16S413, defined by D16S3048, encompassed approximately by a 4-cM region. Homozygous deletions of any exons in 17HSDB2 gene were identified in 7 of 27 cases (26%). Automated sequencing analysis of 17HSDB2 failed to demonstrate mutations in any of these specimens. Our data suggest that the 17HSDB2 locus is a frequent target of deletion in HCC but the inactivation of 17HSDB2 may not involve sequence mutations. Furthermore, the presence of the other 2 frequent LOH regions suggest that the putative tumor suppressor genes at these locations might be involved in the development of HCC.

Activation of protein kinase A and atypical protein kinase C by A(2A) adenosine receptors antagonizes apoptosis due to serum deprivation in PC12 cells

We found in the present study that stimulation of A(2A) adenosine receptors (A(2A)-R) prevents apoptosis in PC12 cells. This A(2A)-protective effect was blocked by protein kinase A (PKA) inhibitors and was not observed in a PKA-deficient PC12 variant. Stimulation of PKA also prevented apoptosis, suggesting that PKA is required for the protective effect of A(2A)-R. A general PKC inhibitor, but not down-regulation of conventional and novel PKCs, readily blocked the protective effect of A(2A)-R stimulation and PKA activation, suggesting that atypical PKCs (aPKCs) serve a critical role downstream of PKA. Consistent with this hypothesis, stimulation of A(2A)-R or PKA enhanced nuclear aPKC activity. In addition, the A(2A)-protective effect was blocked by a specific inhibitor of one aPKC, PKCzeta, whereas overexpression of a dominant-positive PKCzeta enhanced survival. In contrast, inhibitors of MAP kinase and phosphatidylinositol 3-kinase did not modulate the A(2A)-protective effect. Dominant-negative Akt also did not alter the A(2A)-protective effect, whereas it significantly reduced the protective action of nerve growth factor. Collectively, these data suggest that aPKCs can function downstream of PKA to mediate the A(2A)-R-promoted survival of PC12 cells. Furthermore, the results indicate that different extracellular stimuli can employ distinct signaling pathways to protect against apoptosis induced by the same insult.

Correlation of histologic subtypes and replication error phenotype with comparative genomic hybridization in gastric cancer

To characterize phenotypic and genotypic changes in gastric cancer (GC), DNA copy number aberrations (CNAs) were assessed in 53 tumors using comparative genomic hybridization (CGH) and correlated with clinicopathologic characteristics and status of TP53 and replication error (RER). The number of CNAs per tumor was 6.8 (gain 5.3, loss 1.5), and the number of changes was significantly higher in tumors with advanced stage, TP53 mutation, and without RER than in those with early stage (7.7 vs. 3.0), no TP53 mutations (12.4 vs. 4.8) or RER phenotype (8.2 vs. 2.6). Frequent abnormalities included gains on chromosomal arms 8q (43%), 6q (26%), 11q (26%), 13q (24%), 7p (23%), 17q (23%), and 20q (23%), and losses on chromosomal arms 16q (26%), 19p (23%), 5q (19%), 3p (15%), 4q(15%), and 1p (15%). Advanced GC demonstrated a higher prevalence of gains of 8q (51% vs. 10%, P < 0.05) and loss of 16q (33% vs. 0%, P < 0.05) than early GC. Gains on 8q (64% vs. 20%, P < 0.05), 17q (39% vs. 4%, P < 0.05) and losses on 3p (25% vs. 4%, P = 0.05) and 5q (32% vs. 4%, P < 0.05) were higher in intestinal GC than in diffuse GC. On the other hand, gains on 13q were more common in the diffuse type (40% vs. 11%, P < 0.05). As compared with noncardia cancer, cardia cancer showed more gains on 7p (58% vs. 12%, P < 0.05) and 20q (58% vs. 12%, P < 0.05) and more losses on 4q (50% vs. 5%, P < 0.05). The finding of histology-related aberrations and the combination of CGH and molecular data thus provide additional evidence suggesting genetic heterogeneity of GC.

[Childhood t(8;21) acute myelocytic leukemia: a comparison of clinical features and risk factors with adult cases]

Despite the abundance of reports describing adult cases of t(8;21) acute myelocytic leukemia (AML), childhood cases have received little attention. We retrospectively investigated 14 childhood cases of t(8;21) AML, and compared their clinical characteristics with those of adult cases, focusing on the risk factors for poor prognosis. Seventy-one percent of the patients had fever. Their mean leukocyte count was 12,700/microliter, and they showed decreased NAP activity. The cell surface showed positivity for CD13, 33, 19, 34, and HLA-DR. The complete remission rate was 100%, and relapse was observed in three of the patients. Bone marrow eosinophilia was present in a smaller proportion of the childhood cases than in the adult cases. Although an increased leukocyte count, tumor formation, and other risk factors have been reported in adults, there was no correlation between these factors and prognosis in our childhood cases. As children who showed AML relapse had TdT-positive blasts, detectable blast TdT activity may be a risk factor for relapse in childhood cases of t(8;21) AML. However, to confirm this, a study with a larger subject base should be conducted.

Correlation of histologic subtypes and replication error phenotype with comparative genomic hybridization in gastric cancer

To characterize phenotypic and genotypic changes in gastric cancer (GC), DNA copy number aberrations (CNAs) were assessed in 53 tumors using comparative genomic hybridization (CGH) and correlated with clinicopathologic characteristics and status of TP53 and replication error (RER). The number of CNAs per tumor was 6.8 (gain 5.3, loss 1.5), and the number of changes was significantly higher in tumors with advanced stage, TP53 mutation, and without RER than in those with early stage (7.7 vs. 3.0), no TP53 mutations (12.4 vs. 4.8) or RER phenotype (8.2 vs. 2.6). Frequent abnormalities included gains on chromosomal arms 8q (43%), 6q (26%), 11q (26%), 13q (24%), 7p (23%), 17q (23%), and 20q (23%), and losses on chromosomal arms 16q (26%), 19p (23%), 5q (19%), 3p (15%), 4q(15%), and 1p (15%). Advanced GC demonstrated a higher prevalence of gains of 8q (51% vs. 10%, P < 0.05) and loss of 16q (33% vs. 0%, P < 0.05) than early GC. Gains on 8q (64% vs. 20%, P < 0.05), 17q (39% vs. 4%, P < 0.05) and losses on 3p (25% vs. 4%, P = 0.05) and 5q (32% vs. 4%, P < 0.05) were higher in intestinal GC than in diffuse GC. On the other hand, gains on 13q were more common in the diffuse type (40% vs. 11%, P < 0.05). As compared with noncardia cancer, cardia cancer showed more gains on 7p (58% vs. 12%, P < 0.05) and 20q (58% vs. 12%, P < 0.05) and more losses on 4q (50% vs. 5%, P < 0.05). The finding of histology-related aberrations and the combination of CGH and molecular data thus provide additional evidence suggesting genetic heterogeneity of GC.

Regulated workplace ketones and their interference in the PFBHA method for aldehydes

Ketones are the major positive interferences for an aldehyde dynamic air sampler that consists of 200-mg 20 percent (w/w) O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) on Tenax TA contained in a Pyrex tube 7-mm OD, 5-mm ID, and 70-mm in length, that utilizes a personal battery-powered pump at 10-50 mL/min. The ketone O-oxime derivatives were synthesized to allow absolute quantitation of O-oximes formed during sampling. Wet spiking allowed ketone recoveries to be found. Ketone vapors of known concentrations were generated statically in Tedlar gas bags. The O-oximes were desorbed with hexane, and an aliquot injected for gas chromatographic analysis on a nonpolar capillary column with mass spectrometric or electron capture detection. Gas phase recoveries up to 200 ppm-hour loadings exceeded 75 percent at 25 degrees C for chloroacetone, cyclohexanone, diacetone alcohol, diethyl ketone, dipropyl ketone, ethyl butyl ketone, methyl amyl ketone, methyl butyl ketone, 2-methylcyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, methyl isopropyl ketone, and methyl propyl ketone. The recoveries for acetophenone, 2-chloroacetophenone, and ethyl amyl ketone were lower than 75 percent, and were caused by steric hindrance. Sampling for both aldehydes and ketones is recommended at 10 mL/min for TLV concentrations.

Cancer chemotherapy and somatic cell mutation

The occurrence of a second neoplasm is one of the major obstacles in cancer chemotherapy. The elucidation of the genotoxic effects induced by anti-cancer drugs is considered to be helpful in identifying the degree of cancer risk. Numerous investigations on cancer patients after chemotherapy have demonstrated: (i) an increase in the in vivo somatic cell mutant frequency (Mf) at three genetic loci, including hypoxanthine-guanine phosphoribosyl-transferase (hprt), glycophorin A (GPA), and the T-cell receptor (TCR), and (ii) alterations in the mutational spectra of hprt mutants. However, the time required for and the degree of such changes are quite variable among patients even if they have received the same chemotherapy, suggesting the existence of underlying genetic factor(s). Accordingly, some cancer patients prior to chemotherapy as well as patients with cancer-prone syndrome have been found to show an elevated Mf. Based on the information obtained from somatic cell mutation assays, an individualized chemotherapy should be considered in order to minimize the risk of a second neoplasm.

A more efficient method of texture use in surgical robot simulation

Texture mapping is a crucial supplement to modeling in 3D graphic simulation technology. Relatively small objects in a simulation environment can be represented with textures rather than by modeling, which helps economize on precious data storage space. Textures also lend some surfaces a more realistic appearance, both for the user and the viewer. The production of a texture, however, is a very complex process of repeated trial-and-error approximations. This inspired the idea of using mathematical formulas to determine the optimal texture so that the desired simulation environment is achieved with maximum effect and efficiency. In this paper the mathematical formulas for producing optimal texture are described. The results are presented as applied in a surgical robot simulation environment in an operating room.

Molecular genetic study of Pompe disease in Chinese patients in Taiwan

Pompe disease is caused by mutations in the acid alpha-glucosidase (GAA) gene. Multiple kinds of mutations in the GAA gene have been reported worldwide. In order to elucidate the molecular basis of the disease in Taiwanese patients of Chinese origin, we have recruited 11 unrelated families who had at least one member with Pompe disease for study. We used 16 pairs of oligonucleotide primers to amplify all the coding regions from exon 2 to 20 in the family members. The coding regions were sequenced on both the sense and antisense strands. We identified 7 different mutations in 17 alleles but failed to identify the defects in the other 5 alleles. The most common defect was D645E (Asp645Glu), accounting for 36% (8/22 alleles) of mutations, followed by G615R (Gly615Arg) (3 alleles); 1411del4 (Glu471-shift) (2 alleles); and one allele each of R600H (Arg600His); deltaN675 (deltaAsn675); 2380delC (Arg794-shift) and 2815delGT (Val939-shift). The molecular defects of Pompe disease are highly heterogeneous in Chinese. Characterization of the molecular defects of the disease is useful for a genotype-phenotype correlation and for genetic counseling and prenatal diagnosis.

Hemophagocytosis by leukemic blasts in 7 acute myeloid leukemia cases with t(16;21)(p11;q22): common morphologic characteristics for this type of leukemia

BACKGROUND

In a previous study of a case of acute megakaryoblastic leukemia with t(16;21)(p11;q22), which displayed hemophagocytosis by leukemic blasts, the authors mentioned that the same type of morphology had been cited in the literature for 4 other cases of acute myeloid leukemia (AML) with the same translocation. This observation prompted the authors to examine more cases of AML with t(16;21)(p11;q22) for this morphology.

METHODS

The authors reviewed bone marrow smears for the presence of hemophagocytosis in 7 patients with AML identified as having t(16;21)(p11;q22).

RESULTS

The leukemias belonged to the FAB-M1/M7 (n = 5), M5b (n = 2), and contained phagocytic blasts in various percentages (< 0.2-36.7%). The blasts contained either single or multiple cytoplasmic vacuoles, in some of which the phagosomes were visible. The engulfed hemopoietic cells (red cells, erythroblasts, lymphocytes, and thrombocytes) were also noted in their cytoplasm. These observations confirmed that hemophagocytosis by leukemic blasts is a common and characteristic feature of this type of leukemia.

CONCLUSIONS

The study of 12 cases (the 7 cases described here and the previous 5 cases) strongly supports the hypothesis that hemophagocytosis by leukemic blasts is common and characteristic in this type of leukemia, which may be related to the specific chromosome aberration of t(16;21)(p11;q22).

[Three pediatric cases of erythroleukemia: review of the literature on prognostic factors]

We encountered 3 patients with erythroleukemia who showed differing outcomes. The first patient was an 11-year-old girl who was treated with an ANLL 91 national protocol followed by bone marrow transplantation from an HLA-identical brother. She is still in complete remission after 6 years. The second patient was a 15-year-old girl. Treatment with low dose Ara-C was effective. She experienced a relapse once, but achieved her second remission with low dose-Ara-C plus vitamin D. Up to the present, she has maintained remission for 5 years. The third patient was a 1-month-old girl who initially presented with an increase of proerythroblasts with infiltration to the liver. Although her response to Ara-C and etoposide was favorable, she died of a generalized fungal infection in the leukopenic phase. Chromosomal analyses of bone marrow cells were normal for patients 1 and 2, but patient 3 had an abnormal complex karyotype. We think the prognosis for erythroleukemia in childhood is not necessarily poor in all cases. Appropriate treatment should be based on the patient's age, the proportion of proerythroblasts, and the presence of chromosomal abnormalities.

Loss of heterozygosity at chromosome 13q in hepatocellular carcinoma: identification of three independent regions

Loss of heterozygosity (LOH) on chromosome 13q is one of the most common genetic alterations in hepatocellular carcinoma (HCC) and might be involved in liver cancer development through inactivation of tumour suppressor genes. In order to narrow down the region of 13q loss, we examined the pattern of loss of heterozygosity (LOH) in tumours from 88 HCC patients, using 18 microsatellite markers on 13q. Thirty-eight of the 88 tumours (43%) showed LOH for at least one marker. Of these, two tumours (5%) showed 13q whole arm allelic loss, while the remaining 36 tumours (95%) had partial allelic loss. The LOH pattern defined by the 36 tumours suggested the existence of at least three different smallest common deleted regions which might be involved in the carcinogenesis of HCC. The first, the most centromeric in the 13q12.3 is, close to the BRCA2 gene, defined by D13S171; the second, the most telomeric region in the 13q31-32 band, is defined by D13S154 and D13S157; the third, the intermediate region at 13q14.3, which is near the RB gene, is defined by loci D13S268. The rate of LOH at 13q31-32 was significantly higher in Hepatitis B-surface antigen (HBsAg)-positive patients than HBsAg-negative HCC patients, pointing to a candidate gene related to the development of HBsAg-positive HCCs.

Characterization of selective resistance to insulin signaling in the vasculature of obese Zucker (fa/fa) rats

Both insulin resistance and hyperinsulinemia have been reported to be independent risk factors for cardiovascular diseases. However, little is known regarding insulin signaling in the vascular tissues in insulin-resistant states. In this report, insulin signaling on the phosphatidylinositol 3-kinase (PI 3-kinase) and mitogen-activated protein (MAP) kinase pathways were compared in vascular tissues of lean and obese Zucker (fa/fa) rats in both ex vivo and in vivo studies. Ex vivo, insulin-stimulated tyrosine phosphorylation of insulin receptor beta subunits (IRbeta) in the aorta and microvessels of obese rats was significantly decreased compared with lean rats, although the protein levels of IRbeta in the 2 groups were not different. Insulin-induced tyrosine phosphorylation of insulin receptor substrates 1 and 2 (IRS-1 and IRS-2) and their protein levels were decreased in the aorta of obese rats compared with lean rats. The association of p85 subunit to the IRS proteins and the IRS-associated PI 3-kinase activities stimulated by insulin in the aorta of obese rats were significantly decreased compared with the lean rats. In addition, insulin-stimulated serine phosphorylation of Akt, a downstream kinase of PI 3-kinase pathway, was also reduced significantly in isolated microvessels from obese rats compared with the lean rats. In euglycemic clamp studies, insulin infusion greatly increased tyrosine phosphorylation of IRbeta- and IRS-2-associated PI 3-kinase activity in the aorta of lean rats, but only slight increases were observed in obese rats. In contrast, insulin stimulated tyrosine phosphorylation of MAP kinase (ERK-1/2) equally in isolated microvessels of lean and obese rats, although basal tyrosine phosphorylation of ERK-1/2 was higher in the obese rats. To our knowledge, these data provided the first direct measurements of insulin signaling in the vascular tissues, and documented a selective resistance to PI 3-kinase (but not to MAP kinase pathway) in the vascular tissues of obese Zucker rats.

Inhibitory action of the gonadopeptide inhibin on amphibian (Rana pipiens) steroidogenesis and oocyte maturation

In view of recent reports on the production of inhibin- and activin-like proteins in lower vertebrates and their important role during development, we have examined the effects of the gonadopeptide inhibin in the process of oocyte maturation using amphibian (Rana pipiens) fully grown preovulatory ovarian follicles cultured in vitro. In the presence of frog pituitary homogenate (FPH), which stimulates progesterone (P4) levels and the subsequent germinal vesicle breakdown (GVBD), purified porcine inhibin (35-50 IU) inhibited both of these responses in a dose-dependent manner. Inhibin also blocked GVBD initiated by exogenously added P4 in intact as well as denuded oocytes. Thus, inhibin seems to act at the follicle (granulosa) cells because it blocked steroidogenesis and at the oocyte because it altered the steroid-induced oocyte maturation. The P4-treated follicles were susceptible to the inhibin action during the first 3 hr of steroid stimulation, which indicates that inhibin affects some early events during the process of GVBD. Maximum inhibitory effect was observed when P4 and inhibin were added simultaneously at the beginning of the incubations. Moreover, the inhibitory effect on GVBD caused by the gonadopeptide was dependent on the length of exposure of the follicles to inhibin. The continuous presence of inhibin in the culture was required to block GVBD efficiently. Data also indicate that the inhibitory effect of inhibin was reversible. Taken together, results from this study present evidence that inhibin may be a relevant paracrine/autocrine regulator of ovarian functions.

Acute pure red cell aplasia associated with allopurinol therapy

Several investigators have reported patients with acute pure red cell aplasia (PRCA) caused by anticonvulsants, antibiotics, or antithyroid agents. Allopurinol is known to be a causative agent of aplastic anemia, but there have been few reports of acute PRCA induced by allopurinol. We describe here a 15-year-old boy who suffered from anemia 6 weeks after initiation of allopurinol therapy; his anemia immediately improved after cessation of the drug. His bone marrow showed severe erythroid hypoplasia with a myeloid/erythroid ratio of 18.6 and low expression of glycophorin A detected on cell-surface antigen analysis. No morphological abnormalities were observed in myeloid series and megakaryocytes. The prolonged plasma iron disappearance rate and the decreased plasma iron turnover rate also indicated erythroid hypoplasia. He had been free from any infections, including parvovirus B19, before manifestation of PRCA. Taken together, these results suggest a diagnosis of acute PRCA. This side effect of allopurinol should be taken into consideration.

Loss of heterozygosity and microsatellite instability in hepatocellular carcinoma in Taiwan

Elucidation of the basic genetic changes of human hepatocellular carcinoma is important for the understanding and treatment of this cancer. We used microsatellite polymorphism markers to study 30 cases of hepatocellular carcinoma (34 tumours) on all human chromosomes. DNA from 34 pairs of hepatocellular carcinomas and corresponding non-tumour parts was prepared. Loss of heterozygosity (LOH) and microsatellite instability on 23 chromosomes were investigated by 231 sets of microsatellite markers. More than 20% LOH was shown for loci on 16q (47.1%), 13q (32.4%), 17p (32.4%), 5q (26.5%), 11p (23.5%) and 9p (20.6%). The commonly affected regions were mapped to 16q12.1, 16q12.2, 16q24, 13q12.1-32, 17p13, 5q32, 5q34, 5q3, 11p15, 11q23-24 and 9p21. Hepatitis B virus carriers had a significantly higher frequency of LOH on chromosomes 5q, 11p and 16q. Furthermore, larger tumour size tended to have higher frequency of LOH at D16S409 locus (16q12.1). Microsatellte instability was only found in 12 of 231 markers and the frequency is very low. These data suggest that the chromosomes 16q, 13q, 17p, 5q, 11p and 9p might participate in hepatocarcinogenesis. However, microsatellite instability might play little role in the development of this cancer in Taiwan.

Glove permeation tests using novel microchemical techniques for 2, 4-dichlorophenoxyacetic acid (2,4-D) derivatives

The aim was to assess the permeation of different herbicide emulsion concentrate formulations of 2,4-dichlorophenoxyacetic acid (2,4-D) as 60.8 and 83.5% butoxyethyl ester (BEE) and 46.8% dimethyl amine salt (DMAS) through four types of glove materials (lined unsupported nitrile, unlined unsupported butyl, Silver Shield laminate, and Viton). This entailed the development of new microchemical techniques to allow sensitive capillary gas chromatography/mass spectrometry (GC/MS) of the permeated herbicide. The 2,4-D DMAS was esterified to the methyl ester by boron trifluoride-methanol complex with 99.2 +/- 3.7% efficiency using microwave heating to minimize reaction time and to process microsamples. The GC/MS detection limit was 5 ng/ml (ppb) of 2,4-D DMAS in the collection medium. The permeates from the ester formulations were analyzed directly for the ester above the detection limit of 9 ng/ml (ppb) BEE. The permeation investigations utilized the American Society for Testing Materials (ASTM)-type permeation cells with liquid collection media. The results showed that these gloves could provide at least 6 h protection for these formulations.

Chromosomal abnormality in hepatocellular carcinoma by comparative genomic hybridisation in Taiwan

The elucidation of the genetic changes of hepatocellular carcinoma (HCC) is very important for understanding the molecular mechanism of liver carcinogenesis. In order to identify the gains or losses in DNA sequence copy number in HCC, we used comparative genomic hybridisation to study 40 cases (44 tumours) of HCC. Tumour DNA and DNA from non-neoplastic liver tissue were labelled with different fluorochromes and then simultaneously hybridised to normal metaphase spread chromosomes. An image acquisition system was used to quantitate signal intensities contributed by tumour and reference DNA along the entire length of each chromosome. Regions of amplification and deletion were demonstrated as quantitative alterations. Losses were prevalent on chromosome regions 16q (43%), 17p (20%), 13q (20%), 4q (15%) and 8p (15%). Gains frequently occurred on 8q (30%), 1q (20%), 6p (20%) and 17q (18%). Hepatitis B virus carriers had a significantly higher frequency of losses on chromosome 16q. Furthermore, the minimal region of losses was narrowed down to 16q11-q22. This study confirms the presence of previously known chromosomal aberrations in HCC and highlights a new significant correlation between losses on chromosome 16q and hepatitis B virus carriers.

Biomarkers in long survivors of pediatric acute lymphoblastic leukemia patients: late effects of cancer chemotherapy

In order to elucidate the late effects of cancer chemotherapy, mutant frequencies (Mfs) at the hypoxanthine phosphoribosyl transferase (hprt) locus were evaluated in pediatric patients with early pre-B acute lymphoblastic leukemia (ALL). Hprt-Mfs were measured at least 2 years after completion of chemotherapy. Ten out of 15 patients were found to have hprt-Mfs exceeding the 99% confidence limits as calculated from observations of healthy controls. Although there was some intraindividual variation, serial measurements of hprt-Mfs with intervals of more than 6 months revealed that hprt-Mfs were fairly stable. Patients with high Mfs tended to have sibling clones as detected by clonality analysis using the T-cell receptor (TCR) rearrangement pattern, but clonality did not have a major effect on the Mfs. On the other hand, Mfs at the TCR locus and sister chromatid exchange frequency were within the normal range in all patients. These data suggest that chemotherapy can cause persistent genotoxicity in vivo in a subset of pediatric ALL patients and that the hprt-Mf is a useful method for measuring such an effect.

Analysis of mutations at the DNA repair genes in acute childhood leukaemia

Deficiency in DNA repair capability is considered to be responsible for oncogenesis. Hereditary and sporadic cancers in various tissues have been reported to have mutations at the DNA repair genes. In this study we analysed two excision repair genes (ERCC1 and XPCC) and two mismatch repair genes (hMSH2 and hMTH1) in the leukaemic blasts of newly diagnosed paediatric patients by use of reverse transcriptase (RT)-polymerase chain reaction (PCR). Analysis of the leukaemic blasts from 15 patients demonstrated no alterations at the XPCC, hMSH2 or hMTH1 genes. Blasts from one patient with acute mixed lineage leukaemia revealed an abnormally migrated product of the ERCC1 gene by RT-PCR. His leukaemic blasts showed a reduced expression of ERCC1 protein by Western blotting. Since bone marrow cells at remission showed only normally migrated product, the ERCC1 gene mutation was considered to be specific for the leukaemic blasts. This is the first report describing a mutation at the ERCC1 gene in acute childhood leukaemia.

Telomerase activity and telomere length in human hepatocellular carcinoma

Telomerase activity is activated and telomere length altered in various types of cancers, including hepatocellular carcinoma (HCC). A total of 39 HCC tissues and the corresponding non-tumour livers were analysed and correlated with clinical parameters. Telomere length was determined by terminal restriction fragment assay, and telomerase activity was assayed by telomeric repeat amplification protocol. Telomerase activity was positive in 24 of the 39 tumour tissues (1.15-285.13 total product generated (TPG) units) and in six of the 39 non-tumour liver tissues (1.05-1.73 TPG units). In the 28 cases analysed for telomere length, telomere length was shortened in 11 cases, lengthened in six cases, and unaltered in 11 cases compared with non-tumour tissues. Neither telomere length nor telomerase activity was correlated to any clinical parameters.

Infrequent mutations and no methylation of CDKN2A (P16/MTS1) and CDKN2B (p15/MTS2) in hepatocellular carcinoma in Taiwan

CDKN2A (p16INK4A/MTS1) and CDKN2B (p15INK4B/MTS2) have recently been shown to be potent inhibitors of the cyclin D/cyclin-dependent kinase-4 complex. Both genes are candidates for the putative tumour suppressor genes located at chromosome 9p21 and are frequently inactivated in many human cancers through homozygous deletion. More recently, another reported pathway of inactivation involves loss of transcription associated with de novo methylation of the 5' CpG island of p16/MTS1 and p15/MTS2 in human cancers. We examined a total of 34 tumours from 30 hepatocellular carcinoma (HCC) patients for deletion, mutation and DNA methylation of these two genes by polymerase chain reaction (PCR) amplification, sequence analysis and Southern blot. Homozygous deletions of P16/MTS1 exon 1 were only identified in 1 of 30 cases (3%). Homozygous deletions of p15 exon 1 or exon 2 were found in 7 of 30 cases (13%). Automated sequencing analysis of p16 exon 1 and 2 and p15 exon 1 and 2 failed to demonstrate mutations in either p16 or p15 in any of these specimens. No aberrant 5' CpG island hypermethylation of p16 or p15 was found in any of the primary tumours by Southern blot. These data suggest that the p16/MTS1 gene has a limited role in HCC. However, deletions of the p15/MTS2 gene are found in 13% HCC and might be involved in a subset of HCC.

Prospective study of mutant frequencies at the hprt and T-cell receptor gene loci in pediatric cancer patients during chemotherapy

Mutant frequencies (MFs) at the hypoxanthine phosphoribosyl transferase gene and the T-cell receptor (TCR) gene loci were evaluated in nine pediatric cancer patients before and during anticancer chemotherapy. The study population consisted of three patients with Hodgkin's disease, four patients with neuroblastoma, and two patients with Wilms' tumor. Except for one patient with neuroblastoma and one patient with Wilms' tumor, MFs at the hypoxanthine phosphoribosyl transferase locus tended to increase during the early cycles of treatment. The elevation was most striking and persistent in patients with Hodgkin's disease. The clonal relationship was determined in mutant cells derived from Hodgkin's disease patients by TCR-gamma gene rearrangement pattern and showed that the elevation of MFs resulted from increased mutational events rather than from clonal expansion of mutants. An increase in TCR MF was also found during chemotherapy in most patients, but the time of TCR MF elevation was variable among patients. Among the chemotherapeutic agents used in this study, cyclophosphamide was considered to be the most mutagenic. Our present study clearly demonstrates that anticancer chemotherapy can induce mutagenesis in vivo in various pediatric cancer patients.

Simultaneous gas chromatographic-mass spectrometric quantitation of the alkylbenzene inert components, pesticide manufacturing by-products and active ingredient in two malathion formulations

A rapid, reliable and effective method for direct determination of the inert components, manufacturing by-products of the pesticide, and active ingredient in two malathion formulations has been established using capillary gas chromatography-mass spectrometry (GC-MS) with the internal standard method. The C2-, C3-, and C4-alkylbenzenes, the major pesticide manufacturing by-products (O,O,S-trimethylthionophosphate, diethyl maleate and O,O,O-trimethylthionophosphate), and malathion were resolved, and quantified in the same chromatogram. Structural identification was based on MS total ion current data, comparison of GC retention times with those of authentic standards, and retention indices. O,O,S-Trimethylthionophosphate was quantified at 3.57 +/- 0.31% (w/w) in one malathion formulation. While the malathion contents were within specifications for both formulations, the total alkylbenzene contents were not.

Second malignancy following treatment of acute lymphoblastic leukemia in children

Second malignancy is one of the serious late effects among long-term survivors of acute lymphoblastic leukemia (ALL) in children. Of 83 newly diagnosed pediatric ALL patients at our hospital between January 1980 and December 1995, four patients were found to have second malignancies. These included MDS/AML after B-ALL, rhabdomyosarcoma after early pre-B ALL, ependymoma after B-ALL, and astrocytoma after early pre-B ALL. The mean duration from initial ALL to second malignancy was 5.2 years. The possible causes of second malignancy in these patients are discussed in this report, along with a review of recent literature.

Measurement of mutation frequency at the HPRT locus in peripheral lymphocytes. Is this a good method to evaluate a cancer risk in pediatric patients?

Validity of measurement of somatic cell mutation frequency (Mf) at the hprt locus for evaluating cancer risk of the given individual was determined in pediatric patients. Peripheral lymphocytes (PL) from patients with various diseases, including acute lymphoblastic leukemia (ALL) and Hodgkin's disease (HD), DNA repair deficient syndromes or short stature receiving growth hormone (GH), were isolated through Ficoll-Hypaque sedimentation with informed consent. Mf at the hprt locus of PL was determined by limiting dilution assay using 6-thioguanine (6-TG). Results were as follows. (1) ALL patients after chemotherapy had higher Mf than that of age-matched controls. (2) Patients with HD tended to have higher Mf after chemotherapy. (3) Among DNA-repair deficient syndromes, diseases which are susceptible to cancer (Xeroderma pigmentosum, Ataxia telangiectasia) have high Mf, but those without any cancer disposition (Cockayne syndrome, Rothmund-Thomson syndrome) have normal Mf. (4) GH-receiving patients have normal Mf, regardless of total doses of GH. Measurement of Mf at HPRT locus may be useful for evaluating cancer risk of pediatric patients.

Gas-phase postderivatization following solid-phase microextraction for determining acidic herbicides in water

This study analyzes acidic herbicides from an aqueous sample by developing a methylated postderivatization on the fiber following solid-phase microextration (SPME) with diazomethane gas procedure combined with GC/MS. Analysis results indicate that a silica fiber coated with polyacrylate (PA) yields a higher extraction efficiency than that obtained with poly(dimethylsiloxane) (PDMS) using the SPME technique. Detection limits are achieved at the level of 10-30 ng/L. Linearity is obtained over a wide range, with precision below 12% RSD. In addition, the significant reduction in extraction efficiency is attributed to the concentration of humic acids exceeding 5 mg/L. Various degradation compounds of acidic herbicides in basic solution are also detected, including 2,4-dichlorophenol, 2,4,5-trichlorophenol, 4-chloro-3-methylphenol, pentachlorinated biphenyl, and tetrachlorinated biphenyl. Moreover, the amount of pentachlorinated biphenyl and tetrachlorinated biphenyl increases over time.

Fluorescence microsatellite analysis to study the parental origin of the supernumerary chromosome in Down's syndrome

OBJECTIVE

Down's syndrome (DS) is an important cause of mental retardation. This study investigated the parental origin of the extra chromosome 21 in DS patients.

METHODS

Fourteen families each with a DS patient were recruited for analysis of nine microsatellite markers on chromosome 21. We collected DNA from both parents and the patient and used polymerase chain reaction to amplify nine segments on chromosome 21: D21S1435, D21S1436, D21S1437, D21S1446, D21S156, D21S258, D21S263, D21S265 and D21S270. One of each pair of DNA primers was labeled with a fluorescence dye. The amplified products were subjected to electrophoresis in a semi-automated DNA sequencer and then analyzed with Genescan software to determine the origin of the extra chromosome 21.

RESULTS

The extra chromosome 21 originated from the mother in 13 (93%) patients and from the father in one (7%) patient.

CONCLUSIONS

Our findings were compatible with those from Caucasian patients. A great majority of Down's syndrome cases resulted from meiotic errors in the eggs.

Evaluation of mutant frequencies at the hprt and the T-cell receptor loci in pediatric cancer patients before treatment

Mutant frequencies (Mfs) at the two genetic loci, the hypoxanthine phosphoribosyl transferase (hprt) gene and the T-cell receptor (TCR) gene were evaluated in pediatric cancer patients before starting chemotherapy or radiotherapy. The study population consisted of 27 patients with various solid tumors (mean age +/- SD; 5.5 +/- 5.1 years, range; 0.2-14.5 years), 5 patients with acute leukemia (10.3 +/- 6.1, 1.3-17.0 years), and 26 healthy controls (11.6 +/- 4.0, 4.4-22.2 years). Although the age distributions were different, the mean Mf values of the hprt and the TCR loci were comparable among these three groups. On an individual basis taking the age factor into consideration, the hprt-Mfs of 3 patients with solid tumors, i.e., two patients with Hodgkin's disease and one patient with Askin tumor, were found to be well above the 95% confidence limit. There were no patients with a TCR-Mf exceeding the 95% confidence limit. These data suggest the possibility that some patients with solid tumors may be predisposed to mutational susceptibility before treatment. The assay of the hprt-Mf appears more sensitive than the TCR-Mf assay in distinguishing these patients.

Molecular characterization and PCR diagnosis of Thailand deletion of alpha-globin gene cluster

Thailand deletion of alpha-Thalassemia (thal) 1 involves the zeta2-, phi zeta1-, alpha2-, alpha1-, and theta1-globin genes. In Southeast Asians and Taiwanese, this mutation is the second most common long-segment deletion of two alpha-globin genes, after the Southeast Asian deletion. To define the Thailand deletion breakpoints, we used polymerase chain reaction (PCR) to amplify the normal-sequence DNA fragments across the breakpoints. The amplified products were sequenced directly or after cloning into pGem-3Z or pCR2.1 vectors. Comparison of the normal and mutant sequences revealed that the 5' breakpoint lies between nucleotides 1,269 and 1,290 upstream of the initiator codon adenine of the zeta2-globin gene, and the 3' breakpoint lies between nucleotides 29,387 and 29,408 downstream of it. A total of 30,677 nucleotides were deleted. Both breakpoints mentioned above lie within the Alu repetitive sequences and an extensive sequence homology is present around the two breakpoints. These findings suggest that homologous recombination is the mechanism by which the deletion occurs. Based on our data, we used three oligonucleotide primers to amplify the regions across the deletion and its corresponding normal sequence. The feasibility of PCR diagnosis was confirmed in 20 carriers with this deletion.

Role of protein tyrosine phosphorylation in etoposide-induced apoptosis and NF-kappa B activation

When a human myeloid cell line, U937, was incubated with etoposide (10 micrograms/mL), morphologically apoptotic cells first appeared at 3 hr and increased with time to 50% at 6 hr. Pretreatment of U937 cells for 30 min with a potent tyrosine kinase inhibitor, herbimycin A (10 microM), significantly suppressed the appearance of apoptotic morphological changes. Concomitantly, herbimycin A pretreatment prevented both high molecular weight and internucleosomal DNA fragmentation induced by etoposide. Two major bands at 30 and 66 kDa with enhanced tyrosine phosphorylation inhibited by herbimycin A were detectable after 30 min of incubation with etoposide. In addition, herbimycin A prevented etoposide-induced NF-kappa B activation. The expressions of Bcl-2 and Bax, on the other hand, were not affected by herbimycin A pretreatment. Herbimycin A was also found to inhibit 1-beta-D-arabinofuranosylcytosine-induced apoptotic changes and NF-kappa B activation. These results suggest that activation of tyrosine kinase(s) may play an important role in apoptotic processes induced by a variety of anti-cancer drugs.

NADH dehydrogenase deficiency in an apoptosis-resistant mutant isolated from a human HL-60 leukemia cell line

An apoptosis-resistant mutant (VC-33) was selected from HL-60 by alternating exposure to camptothecin and etoposide. VC-33 cells demonstrated resistance to apoptosis as induced not only by camptothecin and etoposide but by a variety of other agents as well, including 1-beta-D-arabinofuranosylcytosine, hydroxyurea, calcium ionophore (A23187), cycloheximide, and UV irradiation. In an effort to identify the mechanism of such apoptosis resistance, a mRNA differential display analysis was used. Among a total of 12 bands with reduced expression in VC-33 cells, 1 cDNA clone was isolated that was hybridized to the wild-type transcript but not to the VC-33 transcript on Northern blotting. Partial sequence of this gene revealed 98% homology to mitochondrial NADH dehydrogenase subunit 5. When cell growth and intracellular ATP levels under glucose starvation were measured, VC-33 cells were found to be more sensitive than wild-type cells. Thus, NADH dehydrogenase deficiency may contribute, at least in part, to the mechanism of resistance to apoptosis in VC-33 cells.

Biometric study of acute primary angle-closure glaucoma

We investigated the biometric characteristics of acute primary angle-closure glaucoma (PACG) patients and sought guidelines to predict subjects at high risk of acute attack. We enrolled 80 patients who suffered acute attack of angle-closure glaucoma and 60 nonglaucoma subjects. The biometric data, measured with A scan ultrasonography, and the outcomes after various treatments were analyzed. Six patients were excluded because they were lost to follow-up. In the acute PACG patients, the axial length (mean +/- standard deviation) was 22.25 +/- 0.77 mm, the anterior chamber depth (corneal thickness included) was 2.28 +/- 0.23 mm, and the lens thickness was 4.94 +/- 0.28 mm. In the nonglaucoma subjects, the axial length was 23.26 +/- 0.76 mm, the anterior chamber depth (corneal thickness included) was 3.11 +/- 0.25 mm, and the lens thickness was 4.48 +/- 0.30 mm. An anterior chamber depth of less than 2.70 mm was the most sensitive (94%) and specific (94%) parameter to differentiate acute PACG patients from nonglaucoma subjects. The intraocular pressure was controlled within the satisfactory range in 58 patients by laser iridectomy, with or without antiglaucoma medication. Eight patients needed additional gonioplasty and eight required filtering surgery to control the intraocular pressure. Our findings provide useful information about the biometric data of eyes of patients with acute angle-closure glaucoma and offer a useful guide to predict those patients at high risk of acute attack.

Inhibition of superoxide production and chemotaxis by methotrexate in neutrophils primed by TNF-alpha or LPS

We have demonstrated recently that methotrexate (MTX) inhibits superoxide generation and chemotaxis induced by N-formylmethionyl-leucyl-phenylalanine (fMLP) in neutrophils primed by granulocyte colony-stimulating factor (G-CSF). To extend these observations, we examined the in vitro effect of MTX on fMLP-stimulated superoxide generation and chemotaxis in neutrophils primed by either tumor necrosis factor alpha (TNF-alpha) or bacterial lipopolysaccharide (LPS). MTX inhibited superoxide generation and chemotaxis more efficiently in TNF-alpha- or LPS-primed neutrophils than in unprimed neutrophils. When either hypoxanthine or guanosine was added to the culture medium, the effects of MTX were partially counteracted. Furthermore, MTX caused a significant inhibition of both superoxide production induced by phorbol 12-myristate-13-acetate and chemotaxis induced by interleukin 8 in G-CSF-primed neutrophils. These results may support the hypothesis that neutrophils primed by different stimuli are more susceptible to the inhibitory effects of MTX on superoxide generation and chemotaxis irrespective of chemoattractants. Such an effect can be partly attributed to the perturbation of purine nucleotide biosynthesis.

Apoptosis-resistant phenotype selected by alternating exposure to camptothecin and etoposide

We selected an apoptosis-resistant subline (VC-33) in a human promyelocytic leukemia cell line, HL-60, by alternating exposure to camptothecin (CPT) and etoposide (VP-16). When wild-type (WT) and VC-33 cells were incubated with various concentrations of either CPT or VP-16 for 4 h, VC-33 showed several-fold resistance to apoptosis induced by these agents in comparison with WT cells. VC-33 cells also exhibited cross-resistance to apoptosis induced by 1-beta-d-arabinofuranosylcytosine, hydroxyurea, a calcium ionophore (A23187), cycloheximide, or UV irradiation. The levels of protein-DNA cross-linking induced by CPT or VP-16, and the amounts of ara-CTP generation, tended to be smaller in VC-33 cells, but the difference was not sufficient to explain the difference in the sensitivity to apoptosis. The initial rise of intracellular calcium ions with A23187 and the expression of P-glycoprotein, Bcl-2, and Bcl-Xl were comparable between WT and VC-33 cells. This mutant may represent a new phenotype of resistance to apoptosis induced by a variety of agents, and may thus be useful in the study of the mechanisms of apoptosis.

Constitutive endonuclease to induce high molecular weight or internucleosomal DNA fragmentation in freshly isolated leukemia cells

Using an autodigestion method, we investigated endogenous endonuclease(s) in leukemia cells freshly obtained from pediatric patients with various types of leukemia. Endonucleolytic activity was found to cause both high molecular weight and internucleosomal DNA fragmentation at a neutral pH in whole cell lysates of all common acute lymphoblastic leukemia (cALL) blasts, which was Mg2+-dependent and Ca2+-independent. Whole lysates from most acute myeloblastic leukemia (AML) cells possessed similar endonuclease activity, but both Mg2+ and Ca2+ were required for the activity. Our results suggest that leukemia cells of different lineages have distinct constitutive endonucleases, which may play a role in the occurrence of apoptosis in these cells.

Characterization of protein kinase C beta isoform activation on the gene expression of transforming growth factor-beta, extracellular matrix components, and prostanoids in the glomeruli of diabetic rats

Induction of protein kinase C (PKC) pathway in the vascular tissues by hyperglycemia has been associated with many of the cellular changes observed in the complications of diabetes. Recently, we have reported that the use of a novel, orally effective specific inhibitor of PKC beta isoform (LY333531) normalized many of the early retinal and renal hemodynamics in rat models of diabetes. In the present study, we have characterized a spectrum of biochemical and molecular abnormalities associated with chronic changes induced by glucose or diabetes in the cultured mesangial cells and renal glomeruli that can be prevented by LY333531. Hyperglycemia increased diacylglycerol (DAG) level in cultured mesangial cells exposed to high concentrations of glucose and activated PKC alpha and beta1 isoforms in the renal glomeruli of diabetic rats. The addition of PKC beta selective inhibitor (LY333531) to cultured mesangial cells inhibited activated PKC activities by high glucose without lowering DAG levels and LY333531 given orally in diabetic rats specifically inhibited the activation of PKC beta1 isoform without decreasing PKC alpha isoform activation. Glucose-induced increases in arachidonic acid release, prostaglandin E2 production, and inhibition of Na+-K+ ATPase activities in the cultured mesangial cells were completely prevented by the addition of LY333531. Oral feeding of LY333531 prevented the increased mRNA expression of TGF-beta1 and extracellular matrix components such as fibronectin and alpha1(IV) collagen in the glomeruli of diabetic rats in parallel with inhibition of glomerular PKC activity. These results suggest that the activation of PKC, predominately the beta isoform by hyperglycemia in the mesangial cells and glomeruli can partly contribute to early renal dysfunctions by alteration of prostaglandin production and Na+-K+ ATPase activity as well as the chronic pathological changes by the overexpression of TGF-beta1 and extracellular matrix components genes.