A new method of quantification of pipemidic-acid by capillary zone electrophoresis with end-column amperometric detection

Capillary zone electrophoresis was employed for the determination of pipemidic acid using an end-column amperometric detection with a carbon fiber microdisk array electrode, at a constant potential of -1.10 V vs. saturated calomel electrode. The optimum conditions of separation and detection were 1.2 x 10(-4) mol/LNaOAc - 8.8 x 10(-4) mol/ LHOAc for the buffer solution, 20 kV for the separation voltage, 5 kV and 10 s for the injection voltage and the injection time. The limit of detection was 1.05 x 10(-7) mol/L or 189 amol (S/N=3). The relative standard deviation was 0.31% for the migration time and 2.0% for the electrophoretic peak current. The method was applied to determining pipemidic acid in human serum.

[An establishment of murine drug-resistant cell line transfected with human MDR-1 gene.]

BACKGROUND

To investigate the relationship between MDR-1 gene expression and drug resistance in lung cancer cells.

METHODS

The multidrug resistant cell line (3LL-MDR-1) was established by transfecting human MDR-1 gene expressing vector into a murine Lewis lung cancer cell line (3LL) . Drug resistance and the effect of valapamil (VLP) on the resistance were evaluated by MTT assay. The expression of MDR-1 gene product , P-gp , was measured immunohistochemically. The influx and efflux of Rhodamine 123 was tested with flow cytometry.

RESULTS

The MDR cell line expressing P-gp was established , which exhibited a typical drug resistance to vincristine (VCR) , vindesin (VDS) , etoposide (VP-16) , mitomycin (MMC) , taxol and navelbine (NOR) . Valapamil was able to reverse the resistance of the gene-transfected cells and the reversion was dose-dependent. Flow cytometric analysis showed that the resistant cells had much higher ability to export Rhodamine 123 than the parent cells did. The expression of P-gp protein was visualized immunohistochemically.

CONCLUSIONS

The results indicate that drug resistance in lung cancer cells is closely related to the MDR-1 gene expression.

Quality of nucleic acids extracted from fresh prostatic tissue obtained from TURP procedures

PURPOSE

The molecular genetic study of benign prostatic hyperplasia (BPH) requires high quality nucleic acids from BPH tissue. It has been generally assumed, but not experimentally proven, that the diathermy used in trans-urethral resection of the prostate (TURP) damages nucleic acids.

MATERIALS AND METHODS

Total RNA, polyA+ RNA and genomic DNA isolated from fresh tissue obtained from TURP procedures were compared with those isolated from tissue obtained from open prostatectomy.

RESULTS

On a formaldehyde agarose gel, there was an increase in low molecular weight RNA in the TURP derived samples, in comparison to that in the open prostatectomy derived samples. The 28S and 18S rRNA were present in all TURP specimens and although the two bands were reduced in some samples, there were samples in which the 2 bands were indistinguishable from the open prostatectomy derived samples. Low molecular weight fragments seen in total RNA were reduced greatly in polyA+ RNA and the difference in polyA+ RNA between the TURP and open prostatectomy derived samples was significantly diminished. RT-PCR of two ubiquitously expressed gene transcripts (Galpha11, 256 bp and HPRT, 847 bp) yielded products of similar size and intensity between TURP and open prostatectomy derived samples. Genomic DNA obtained from TURP derived specimens showed no difference in size or enzyme digestibility in comparison to that from open prostatectomy.

CONCLUSIONS

Nucleic acids extracted from fresh prostatic tissue derived from TURP procedures can be used as readily as any other fresh tissue for RT-PCR based molecular genetic studies, although polyA+ RNA isolation is recommended if degradation-free RNA is required.

CT scanning and arthroscopic evaluation of patellofemoral malalignment

OBJECTIVE

To determine the pattern of malalignment and the extent of chondral damage, the patellofemoral joint was evaluated by CT scanning and the findings were proved by arthroscopic examination.

METHODS

In 20 cases, 40 knees were examined by CT scanning with and without quadriceps contraction in order to differentiate between static and dynamic abnormalities. The CT images were analyzed. The arthroscopic examination was carried out for 27 knees in 20 cases.

RESULTS

Ten knees had static patellar lateral subluxation and 16 knees dynamic lateral subluxation. Eleven knees had static patellar lateral tilt, and 7 knees dynamic tilt. All of the 27 knees showed arthroscopic patellar maltracking and chondral damage.

CONCLUSIONS

The patellofemoral alignment, affection of quadriceps, and the extent of tight retinaculum may be precisely evaluated by CT measurement and proved by arthroscopic examination.

Quantitation of caffeine by capillary zone electrophoresis with end-column amperometric detection at a carbon microdisk array electrode

Capillary zone electrophoresis is employed for the determination of caffeine using end-column amperometric detection with a carbon fiber microdisk array electrode at a constant potential of 1.45 V versus a saturated calomel electrode. The optimum conditions of separation and detection are 0.1 52mM NaH2PO4-0.648mM Na2HPO4 for the buffer solution, 20 kV for the separation voltage, 5 kV for the injection voltage, and 10s for the injection time. The limit of detection is 2.9 x 10(-4)mM or 1.2 fmol (signal-to-noise ratio = 2). The relative standard deviation is 0.68% for the migration time and 2.3% for the electrophoretic peak current. The method is applied to determining caffeine in human serum and a cola drink.

[The effect of vasectomy on spermatogenesis and proliferation of rat spermatogenic cell]

In order to explore the effect of vasectomy on spermatogenesis and proliferation of rat spermatogenic cell, we detected the DNA content of rat spermatogenic cells by flow cytometry at 4 weeks and 8 weeks after vasectomy. The results showed that the percentages of 1C cell group (spermatid and sperm) in the two experimental groups were apparently lower than that of the two control groups respectively (P < 0.05), but the percentage of 2C cell group (spermatogonium and spermotocyte) in the two experiment groups were much higher than those of the two control groups respectively (P < 0.05); The proliferation index (PI) of experimental groups was significantly lower than that of control groups (P < 0.05) and most of the cells in the experimental groups were on G0/G phase. The percentage of S-phase cell in the 8 weeks experimental group was obviously lower than that of the 4 weeks experimental group. These findings suggest that vasectomy in rat may affect many stages in spermatogenesis and delay the proliferation of spermatogenic cell.

[Surface-enhanced Raman spectroscopy of riboflavin in silver colloids using 1 064 nm excitation]

Surface-enhanced Raman spectra (SERS) of riboflavin in silver colloids, using near-infrared (NIR) laser operating at 1 064 nm wavelength, were obtained. The enhancement factor was further increased by improving the preparation of silver colloid and with the addition of a small amount of NaOH. The detection limit was lower than 3.2 x 10(-10) mol x L(-1). It is concluded that the larger and aggregated silver particles were more efficient for the electromagnetic enhancement of NIR-SERS. Flavin ring was absorbed on the colloidal silver methal surface, standing on oxygens of C(20)=O) and C(4)=O.

Surfactant protein D stimulates phagocytosis of Pseudomonas aeruginosa by alveolar macrophages

Surfactant protein (SP)-D is an oligomeric glycoprotein belonging to the family of collagen-like lectins known as collectins, which have previously been shown to stimulate phagocytosis and other immune cell functions. The hypothesis investigated in this study was that SP-D would stimulate the phagocytosis of an important pulmonary pathogen, Pseudomonas aeruginosa. SP-D, isolated from the lavage fluid of silica-treated rats, significantly enhanced the uptake of three of six strains of P. aeruginosa by rat alveolar macrophages as analyzed by both fluorescence and electron microscopy. SP-D had only minimal effects on phagocytosis of Haemophilus influenzae. SP-D bound to live P. aeruginosa, and binding was inhibited by chelation of calcium and by a competing saccharide, inositol. In vitro killing assays demonstrated that macrophage-mediated killing of one of the mucoid strains of P. aeruginosa was modestly enhanced by SP-D. P. aeruginosa was not measurably aggregated by SP-D either macroscopically or microscopically. Further, SP-D does not appear to act as an activation ligand because adherence of macrophages to SP-D- coated slides did not stimulate the uptake of P. aeruginosa. These findings suggest that SP-D may be important in controlling the pathogenesis of P. aeruginosa in the lung.

Dynamic DNA hybridization on a chip using paramagnetic beads

Dynamic DNA hybridization is presented as an approach to perform gene expression analysis. The method is advantageous because of its dynamic supplies of both DNA samples and probes. The approach was demonstrated on a microfluidic platform by incorporating paramagnetic beads as a transportable solid support. A glass chip was fabricated to allow simultaneous interrogation of eight DNA target samples by DNA probes. DNA targets were immobilized on beads via streptavidin-biotin conjugation or base pairing between oligonucleotide residues. The DNA/bead complex was introduced into the device in which hybridization took place with a complementary probe. The hybridized probe was then removed by heat denaturation to allow the DNA sample to be interrogated again by another probe with a different sequence of interest. A pneumatic pumping apparatus was constructed to transport DNA probes and other reagents into the microfluidic device while hydrostatic pumping was used for the introduction of paramagnetic beads with samples. After investigating three types of paramagnetic beads, we found Dynabeads Oligo(dT)25 best suited this application. Targets on the beads could be sequentially interrogated by probes for 12 times, and the hybridization signal was maintained within experimental variation. Demonstration of specific hybridization reactions in an array format was achieved using four synthesized DNA targets in duplicate and five probes in sequence, indicating the potential application of this approach to gene expression analysis.

Diagnosis of renal vascular disease with MR angiography

Renal magnetic resonance (MR) angiography allows accurate evaluation of patients suspected to have renal artery stenosis without the risks associated with nephrotoxic contrast agents, ionizing radiation, or arterial catheterization. Other applications of renal MR angiography are mapping the vascular anatomy for planning renal revascularization, planning repair of abdominal aortic aneurysms, assessing renal bypass grafts and renal transplant anastomoses, and evaluating vascular involvement by renal tumors. A variety of pulse sequences provide complementary information about kidney morphology, arterial anatomy, blood flow, and renal function and excretion. Three-dimensional gadolinium-enhanced MR angiography can be combined with several other sequences to produce a comprehensive approach to renal MR angiography. This comprehensive approach is designed to allow hemodynamic characterization of renal artery stenosis with a single MR imaging examination that can be easily completed in 1 hour. Three-dimensional gadolinium-enhanced MR angiography demonstrates the renal arteries along with the abdominal aorta, iliac arteries, and mesenteric arteries in a 20-30-second acquisition that can be performed during breath holding. Numerous projections are reconstructed from a single three-dimensional volume of data acquired with a single injection of contrast material to obtain perpendicular and optimized views of each renal artery.

MR angiography after renal revascularization: spectrum of expected anatomic results and postintervention complications

The use of magnetic resonance (MR) angiography in screening for renal artery stenosis has been extensively evaluated. However, the MR angiographic findings after renal artery revascularization are not as well characterized. The renal artery and parenchyma can be evaluated after revascularization with a comprehensive MR imaging protocol that includes T1- and T2-weighted spin-echo sequences, three-dimensional (3D) gadolinium-enhanced MR angiography, and 3D phase-contrast MR angiography. Because surgical techniques for revascularization vary, knowledge of the surgical procedure is necessary to ensure inclusion of the pertinent anatomy at 3D gadolinium-enhanced MR angiography and to define appropriate 3D phase-contrast MR angiography volumes. The 3D gadolinium-enhanced MR angiography volume can be manipulated to view relevant vascular anatomy at the optimal obliquity and section thickness. This protocol allows robust, noninvasive evaluation of the expected arterial anatomy after revascularization, including renal artery endarterectomy, aortorenal bypass grafts, and extraanatomic reconstructions. In cases of suspected postrevascularization complications, gadolinium-enhanced MR angiography is useful because of its lack of nephrotoxicity and radiation exposure. Immediate complications of renal revascularization include renal artery thrombosis, renal infarction, and perinephric hemorrhage. Long-term complications include aneurysms of bypass grafts and recurrent stenosis of the renal artery.

Surfactant protein A enhances alveolar macrophage phagocytosis of a live, mucoid strain of P. aeruginosa

In this study, we investigate the interaction between surfactant protein A (SP-A) and a live, mucoid strain of Pseudomonas aeruginosa and identify a mechanism of clearance of this organism by alveolar macrophages. (125)I-labeled SP-A bound live, but not heat-killed, P. aeruginosa organisms in a concentration-dependent manner. Unlabeled SP-A bound live bacteria, protein isolated from whole organisms, and specific proteins of the P. aeruginosa outer membrane. The binding of SP-A to P. aeruginosa and outer membrane components was inhibited by either EDTA or mannose. Phagocytosis assays with fluorescent microscopy demonstrated that the percentage of macrophages with internalized FITC-labeled P. aeruginosa was increased 1.8-fold (19 vs. 35%) by pretreating the live bacteria with SP-A. This finding was confirmed by direct visualization of ingested bacteria by electron microscopy. Adhering macrophages to SP-A-coated surfaces attenuated the increased uptake of P. aeruginosa pretreated with SP-A, suggesting that SP-A acts as an opsonin to stimulate macrophage phagocytosis of this strain of P. aeruginosa.

Magnetic resonance imaging in renal transplantation

End stage renal disease is common and can result from a variety of diseases. The expense and morbidity of dialysis has made renal transplantation the preferred treatment when it is available. In the United States, 11,000 renal transplants are performed annually. Because of the limited supply of donor organs, every effort is made to salvage the transplanted kidney that has began to fail. Imaging modalities that are currently used to evaluate transplanted kidneys are ultrasound (US), computed tomography (CT), scintigraphy, intravenous urography (IVU), contrast angiography, and magnetic resonance imaging (MRI). MRI offers multiple advantages. MRI provides cross sectional and vascular information without the risks of ionizing radiation, iodinated contrast, or arterial catheterization. This article describes the role of MR imaging in renal transplantation, technical aspects of image acquisition, and MR findings of post-transplantation complications.

MRA contrast bolus timing with ultrasound bubbles

The purpose of this study was to determine the feasibility of using an ultrasound contrast agent test bolus to determine optimum bolus timing for three-dimensional (3D) gadolinium (Gd)-enhanced magnetic resonance angiography (MRA). Small test doses of ultrasound contrast agent (0.3 ml Optison) were injected intravenously followed immediately by a 20 ml saline flush. Arrival of the contrast agent was detected by spectral Doppler ultrasound (US). This technique was implemented in patients undergoing peripheral vascular MRA and carotid MRA. Arrival of the US contrast agent test bolus was readily detected by the change in amplitude of the Doppler spectrum and by a huge increase in the audio signal amplitude. This contrast travel time measurement accurately guided bolus timing for 3D Gd MRA. Bolus timing for 3D contrast-enhanced MRA can be performed using US, thereby eliminating the problems and MR scanner time required for injecting a test bolus of Gd contrast.

[Changes of blood circulation, muscle and skeletal systems in 30 d tail-suspended [correction of tail-suspented] rats]

OBJECTIVE

To confirm the tail-suspended rat model for the study of countermeasures against weightlessness.

METHOD

The changes of blood circulation, muscle and skeletal systems in control group rats (n = 15) and 30 d tail-suspended rats (n = 15) were compared.

RESULT

Compared with the control group, the hemorrheology and erythrocyte deformability decreased significantly, muscle-fiber atrophy, muscle contraction function decreased, the type I muscle fibers transformed to the type II muscle fibers, bone-mineral content of L3 and load capacity of femur declined, bone metabolism changed in the suspended rats.

CONCLUSION

The tail-suspended rat is a suitable animal model for the study of countermeasures against weightlessness.

[Clinical observation on treatment of 304 patients suffered from acute myocardial infarction with integrated Traditional and Western Medicine]

OBJECTIVE

To make a retrospective survey study on clinical effect and regular pattern of TCM treatment based on Syndrome Differentiation in treating patients of acute myocardial infarction (AMI), admitted in Xiyuan Hospital from January 1978 to December 1997 with integrated traditional Chinese and western medicine.

METHODS

Statistical analysis was made in the following items of 304 patients: age, sex, location of infarction, complication, cause of death, mortality, as well as TCM Syndrome, principle of treatment, prescription and medicinal herbs used.

RESULTS

The incidences of complications in this group for arrhythmia, pump failure, thrombosis were 68.75%, 36.84% and 0.66% respectively, while those in patients treated with western medicine reported by literature in China were 86%-100%, 50% and 2% respectively. Mortality in this group after using thrombolytic therapy was reduced from 17.32% (35/202) to 10.78% (11/102). Types of disease, according to Syndrome Differentiation of TCM, were mainly the Qi-deficiency type, blood stasis type and turbid-phlegm type. And the principle of TCM treatment was mainly to supplement Qi, activate blood circulation and resolve phlegm.

CONCLUSION

Integrated traditional Chinese and western medicine treatment of AMI could reducing incidence of complications, such as arrhythmia, pump failure and thrombosis, and thrombolytic therapy could reduce mortality of patients. The frequently encountered TCM Syndrome types and the corresponding therapeutic methods and prescriptions used in treating AMI have also been summarized in this paper.

IL-9 induces chemokine expression in lung epithelial cells and baseline airway eosinophilia in transgenic mice

Recent data have identified IL-9 as a key cytokine in determining susceptibility to asthma. These data are supported by the finding that allergen-exposed IL-9-transgenic mice exhibit many features that are characteristic of human asthma (airway eosinophilia, elevated serum IgE and bronchial hyperresponsiveness) as compared to the background strain. A striking feature of these animals is a robust peribronchial and perivascular eosinophilia after allergen challenge, suggesting that IL-9 is a potent factor in regulating this process. In an attempt to gain insights into the molecular mechanism governing IL-9 modulation of lung eosinophilia, we investigated the ability of this cytokine to induce the expression of CC-type chemokines in the lung because of their effect on stimulating eosinophil chemotaxis. Here we show that IL-9-transgenic mice in contrast to their congenic controls exhibit baseline lung eosinophilia that is associated with the up-regulation of CC-chemokine expression in the airway. This effect appears to be through a direct action of IL-9 because the addition of recombinant IL-9 to primary epithelial cultures and cell lines induced the expression of these chemokines in vitro. These data support a mechanism for IL-9 in regulating the expression of eosinophil chemotactic factors in lung epithelial cells.

[A clinical research for eosinophilic meningoencephalitis caused by angiostrongyliasis]

OBJECTIVE

To improve the awareness of angiostrongyliasis.

METHODS

The clinical and laboratory data as well as the epidemiological informations of 18 patients with eosinophilic meningoencephalitis caused by Angiostrongylus cantonensis were analyzed.

RESULTS

All the patients had a history of eating raw fresh water snail (Ampularium canaliculatus) before the onset of the disease. Incubation period ranged from 1 to 25 days. The major symptoms of the patients were severe headache and pain in the trunk and limbs. Peripheral blood eosinophilia was noted together with increased eosinophilic count in cerebrospinal fluid. With ELISA sera from patients were specifically IgG-antibody positive against Angiostrongylus cantonensis antigen, but were negative against other parasitic antigens such as Paragonimus westermani, Cysticercus, Cellulosae hominis, Echinococcus granulosus and Trichinella spiralis. Abnormal spot signal was found in 2 cases with brain magnetic resonance imaging. Electroencephalogram showed slow alpha rhythm. All the patients were effectively treated with good combined administration of albendazole and dexamethasone.

CONCLUSION

Angiostrongyliasis is one of the common causes leading to eosinophilic meningoencephalitis. To our knowledge, Wenzhou is the first small outbreak site discovered of angiostrongyliasis in mainland China.

Magnetic resonance imaging of the aorta and branch vessels

Magnetic resonance imaging (MRI) can provide a comprehensive evaluation of the aorta and its major branches. T1-weighted spin-echo images and cine-MRI have long been known to be useful for the evaluation of congenital aortic anomalies, aortic aneurysms, and aortic dissections. Gadolinium (Gd)-enhanced three-dimensional magnetic resonance angiography (MRA) is a more recent development that affords better spatial resolution. This technique can be performed during an individual breath-hold and does not require electrocardiographic gating. The data from Gd-enhanced three-dimensional MRA, furthermore, can be used both for projectional angiographic viewing and for multiplanar reformation. In this article, MRI of the aorta and its major branches will be reviewed, with emphasis on the newer technique of Gd-enhanced three-dimensional MRA.

[Leukocyte glucocorticoid receptor and its mRNA levels in leukemia patients]

OBJECTIVE

To explore factors for differentiating non-Hodgkin's lymphoma cell leukemia (NHLCL) and acute lymphoblastic leukemia (ALL).

METHODS

Leukocyte glucocorticoid receptor (GR) and GR mRNA levels were measured in 22 NHLCL, 18 ALL, 10 chronic lymphocytic leukemia (CLL) patients and 6 healthy subjects by using radio-ligand binding assay and molecular hybridization using GR cDNA as the probe.

RESULTS AND CONCLUSIONS

The leukocyte GR and GR mRNA levels were significantly different between NHLCL and ALL(P < 0.01), and could be used as parameters for differential diagnosis of these two types of leukemia.

[Effects of 7 d head down tilt on cardiopulmonary circulation during orthostasis]

Objective. To accumulate data for further studies on the mechanisms of the decrease of cardiovascular function after weightlessness. Method. Cardiopulmonary circulatory function under supine position and head up tilting (HUT) for 20 min before and after exposure to 7 d 6 degrees head down tilt (HDT) in 6 healthy adults who aged 19-21 were measured with a XXH-2000 lesser (pulmonary) circulation and cardiac function instrument. Result. The 7 d HDT resulted in orthostatic intolerance of the subjects; the reduction of RVET (j-z) and the elevation of RPEP [RVET(Q-j)/(j - z)] indicated a decrease of the right heart function. An obvious decrease of the right heart reserves was also observed under HUT after HDT. Conclusion. hc and hc/hz were demonstrated to be useful parameters to evaluate orthostatic tolerance or to forecast orthostatic syncope. The lesser (pulmonary) circulation and cardiac function testing methods are valuable in evaluating the cardiopulmonary circulatory function during HUT.

Negative regulation of myeloid cell proliferation and function by the SH2 domain-containing tyrosine phosphatase-1

The SH2 domain containing tyrosine phosphatase SHP-1 has been implicated in the regulation of a multiplicity of signaling pathways involved in hemopoietic cell growth, differentiation, and activation. A pivotal contribution of SHP-1 in the modulation of myeloid cell signaling cascades has been revealed by the demonstration that SHP-1 gene mutation is responsible for the overexpansion and inappropriate activation of myelomonocytic populations in motheaten mice. To investigate the role of SHP-1 in regulation of myeloid leukocytes, an HA epitope-tagged dominant negative (interfering) SHP-1 (SHP-1C453S) was expressed in the myelo-monocytic cell line U937 using the pcDNA3 vector. Overexpression of this protein in SHP-1C453S transfectants was demonstrated by Western blot analysis and by detection of decreased specific activity. Growth, proliferation, and IL-3-induced proliferative responses were substantially increased in the SHP-1C453S-overexpressing cells relative to those in control cells. The results of cell cycle analysis also revealed that the proportion of cells overexpressing SHP-1C453S in S phase was greater than that of control cells. The SHP-1C453S-expressing cells also displayed diminished rates of apoptosis as detected by flow cytometric analysis of propidium iodide-stained cells and terminal deoxynucleotidyltransferase-mediated fluorescein-dUTP nick end-labeling assay. While motility and phagocytosis were not affected by SHP-1C453S overexpression, adhesion and the oxidative burst in response to PMA were enhanced in the SHP-1C453S compared with those in the vector alone transfectants. Taken together, these results suggest that SHP-1 exerts an important negative regulatory influence on cell proliferation and activation while promoting spontaneous cell death in myeloid cells.

Cloning, gene structure and genomic localization of an orphan transporter from mouse kidney with six alternatively-spliced isoforms

Two genes were identified and characterized that express cDNAs related to previously identified neurotransmitter and/or osmolyte transporters, but which are expressed specifically in the kidney. RNA transcribed from one of these two genes (XT2) was found to undergo an extensive degree of alternative splicing to generate six distinct isoforms. The intron-exon structure of the XT2 gene and the sites of alternative splicing were identified. Expression of the second gene (XT3) was found to be conserved in human kidney, and partial sequence was obtained from a human cDNA library. The expressions of both XT2 and XT3 RNAs were determined in mouse and human tissues, respectively, and the locations of the two genes within the mouse genome were identified. Screening experiments to identify the substrate(s) of these proteins failed to identify specific uptake with any of the tested compounds; however, immunofluorescent microscopy demonstrated that epitope-tagged variants of the protein products of the XT2 and XT3 cDNAs were present on the plasma membrane of transfected cells.

Modulation of cyclophosphamide activity by O6-alkylguanine-DNA alkyltransferase

PURPOSE

The human medulloblastoma cell line D283 Med (4-HCR), a line resistant to 4-hydroperoxycyclophosphamide (4-HC), displays enhanced repair of DNA interstrand crosslinks induced by phosphoramide mustard. D283 Med (4-HCR) cells are cross-resistant to 1,3-bis(2-chloroethyl)- -nitrosourea, but partial sensitivity is restored after elevated levels of O6-alkylguanine-DNA alkyltransferase (AGT) are depleted by O6-benzylguanine (O6-BG). Studies were conducted to define the activity of 4-HC and 4-hydroperoxydidechlorocyclophosphamide against D283 Med (4-HCR) after AGT is depleted by O6-BG.

METHODS

Limiting dilution and xenograft studies were conducted to define the activity of 4-HC and 4-hydroperoxydidechlorocyclophosphamide with or without O6-BG.

RESULTS

The activity of 4-HC and 4-hydroperoxydidechlorocyclophosphamide against D283 Med (4-HCR) was increased after AGT depletion by O6-BG preincubation. Similar studies with Chinese hamster ovary cells, with or without stable transfection with a plasmid expressing the human AGT protein, revealed that the AGT-expressing cells were significantly less sensitive to 4-HC and 4-hydroperoxydidechlorocyclophosphamide. Reaction of DNA with 4-HC, phosphoramide mustard, or acrolein revealed that only 4-HC and acrolein caused a decrease in AGT levels.

CONCLUSIONS

We propose that a small but potentially significant part of the cellular toxicity of cyclophosphamide in these cells is due to acrolein, and that this toxicity is abrogated by removal of the acrolein adduct from DNA by AGT.

Multiple DNA repair mechanisms and alkylator resistance in the human medulloblastoma cell line D-283 Med (4-HCR)

PURPOSE

We have previously reported preferential repair of DNA interstrand crosslinks in the 4-hydroperoxycyclophosphamide-resistant human medulloblastoma cell line D-283 Med (4-HCR). We now report further studies that explored the potential mechanisms underlying this repair.

METHODS

Limiting dilution assays and Western, Southern, and Northern blots were used to compare specific differences between D-283 Med (4-HCR) and its parental line D-283 Med.

RESULTS

D-283 Med (4-HCR) was cross-resistant to melphalan and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), with O6-alkylguanine-DNA alkyltransferase (AGT) levels of 466+/-164 fmol/mg protein; AGT levels in the parental line, D-283 Med, were 76+/-96 fmol/mg. The increase in AGT activity was not a result of gene amplification. Depleting AGT with O6-benzylguanine partially restored sensitivity to BCNU. Both cell lines were deficient in the human mismatch protein MutLalpha. ERCC4 mRNA and poly(ADP-ribose) polymerase levels were similar in both cell lines, and ERCC1 mRNA levels were 2- to 2.5-fold lower in D-283 Med (4-HCR). Topoisomerase I levels were 2- to 2.5-fold higher in D-283 Med compared with D-283 Med (4-HCR).

CONCLUSION

These results, while illustrating the multiple differences between D-283 Med and D-283 Med (4-HCR), do not explain the enhanced DNA interstrand crosslink repair seen in D-283 Med (4-HCR).

The role of income and education in food consumption and nutrient intake in a Chinese population

The purpose of this study was to investigate the role of socio-economic status in the transition of food consumption and nutritional status in a Tianjin population and to identify some related underlying nutritional problems in this population. A random representative sample of appproximately nine million people in Tianjin was obtained using the stratified multistage cluster sampling method. A total of 2236 eligible subjects (1096 men and 1140 women) aged between 15 and 64 years were enrolled in the autumn of 1992. Food weighing plus a three-day food record method were used to assess food consumption and nutrient intakes. The population was categorized into four income groups by average per capita income and three educational groups by years of education. There were marked differences in daily mean consumption of foods among groups with different income levels and educational attainment after adjustment for confounding factors. The low income and/or least education group consumed more cereals while the high income and/or most educated group consumed more fruit, milk and meat. Due to the differences in food consumption, intakes of protein, fat, riboflavin, calcium, selenium, zinc and vitamin E increased while intakes of carbohydrate and manganese decreased with increasing levels of income and education. Vitamin A, calcium and riboflavin intakes were low in all groups classified by either income or education. Vitamin A intake was lower in the low income group than in the other three groups but intakes of calcium and riboflavin were higher in the high income and/or the most educated group than in the other groups. Socio-economic status plays an important role in food consumption and nutritional status in this population. Low intakes of vitamin A, calcium and riboflavin exist in all socio-economic groups. However, higher income and/or educational attainment contribute to increased intakes of calcium and riboflavin. Higher income also relates to an increased intake of vitamin A.

A cross-cultural study of family and peer correlates of adolescent misconduct

Participants were 4 groups of early adolescents from middle-class backgrounds (European and Chinese Americans in southern California and Chinese in Taipei, Taiwan, and Beijing, China). The 591 adolescents (M age = 13.8 years) completed questionnaires about their involvement in misconduct and about family and peer characteristics. Mothers of a subsample of adolescents (n = 405) also completed a questionnaire about their relationships with their adolescents. The 4 groups of adolescents reported significantly different mean levels of family and peer correlates but showed strikingly similar levels and patterns of self-reported misconduct. Structural equation models revealed that 2 latent variables (family relationships and peer sanctions) accounted for more variance in misconduct among European and Chinese American adolescents (51%-62%) than among the 2 Chinese groups (15%-24%), mainly because of a greater contribution of peer factors in the former groups.

Renal anatomic changes on magnetic resonance imaging and gadolinium-enhanced magnetic resonance angiography after renal revascularization. Original investigation

RATIONALE AND OBJECTIVES

The anatomic and hemodynamic renal changes after renal arterial revascularization (RAR) were investigated.

METHODS

Thirty-seven kidneys and 40 renal arteries were evaluated in 20 patients by using magnetic resonance imaging/magnetic resonance angiography (MRI/MRA) to assess pre- and post-RAR renal length and mass, parenchymal thickness, renal enhancement, renal artery caliber, poststenotic dilation, and signal dephasing on 3D phase contrast (PC). The kidneys and renal arteries were segregated into three groups. Group 1 included 16 patients who benefited from RAR (defined as clinical improvement based on decreased serum creatinine or fewer number of antihypertensive medications) in whom 26 renal arteries in 25 kidneys were studied. Intervention included renal artery endarterectomy (n = 20); aortorenal bypass (n = 3); renal artery reimplantation (n = 3); and percutaneous transluminal angioplasty (PTA; n = 1). A total of 27 interventions was performed, as PTA failed for one patient who subsequently underwent aortorenal bypass before reimaging. Group 2 included four patients who did not clinically benefit. A total of eight revascularized arteries were studied in seven kidneys. In group 3, six renal arteries in five kidneys from groups 1 and 2 without RAS/RAR were analyzed as an internal control.

RESULTS

Technical success (defined as increased vessel caliber after intervention) was achieved in 33 of the 34 revascularized arteries. A statistically significant increase in renal length occurred regardless of clinical outcome (pre-RAR, 9.5 cm; post-RAR, 10.5 cm; P < 0.0001). Parenchymal thickness and renal mass, however, improved only in patients who benefited clinically from RAR. Parenchymal enhancement was unchanged in any of the groups studied. No significant morphologic changes were detected in the control group.

CONCLUSIONS

Magnetic resonance imaging and Gd-MRA detect anatomic and hemodynamic changes that occur with renal revascularization.

Magnetic resonance angiography with gadomer-17. An animal study original investigation

RATIONALE AND OBJECTIVES

Our purpose was to investigate a "blood pool" contrast agent for abdominal and thoracic MR angiography by comparison with standard ionic and nonionic gadolinium-based contrast agents, which redistribute into the extracellular fluid compartment.

METHODS

Abdominal and thoracic MR angiography was performed in three adult dogs using a three-dimensional spoiled gradient echo pulse sequence before and after intravenous administration of one of three gadolinium-based contrast agents (gadopentetate dimeglumine, gadobutrol, and gadomer-17). Each compound was tested at five different doses in all three dogs. Quantitative analysis of signal-to-noise ratio (SNR) was performed in the aorta, inferior vena cava (IVC), liver, spleen, kidney (medulla and cortex), fat, and muscle.

RESULTS

Gadomer-17 improved visualization of vascular anatomy at doses of 0.025, 0.05, 0.1, and 0.2 mmol/kg with three-fold greater aorta SNR during the arterial phase and more than four-fold greater aorta and IVC SNR during the equilibrium phase, in comparison with gadopentetate dimeglumine and gadobutrol at equal doses.

CONCLUSIONS

Gadomer-17 is a promising contrast agent for both arterial phase and equilibrium phase MR angiography.

Gadolinium-enhanced magnetic resonance venography of the portal venous system prior to transjugular intrahepatic portosystemic shunts and liver transplantation. Original investigation

RATIONALE AND OBJECTIVES

The accuracy of gadolinium-enhanced magnetic resonance venography (GdMRV) in identifying visceral venous abnormalities was assessed in patients before they underwent transjugular intrahepatic portosystemic shunt (TIPS) or orthotopic liver transplantation (OLT).

METHODS

Twenty-seven patients with portal hypertension underwent GdMRV and transcatheter venography prior to OLT or TIPS. The gadolinium dose was 0.5 mL/kg (0.25 mmol/kg), administered by rapid hand injection. Coronal 3D spoiled gradient-echo GdMRV was performed in a single breath-hold. Four blinded reviewers retrospectively evaluated coronal maximum intensity projection (MIP) images, while two reviewers evaluated the MIPs and multiplanar reconstructions. Abnormalities that could affect transjugular intrahepatic portosystemic shunt or transplantation were noted and compared with the results of corresponding catheter venograms read by a separate blinded reviewer.

RESULTS

Abnormalities were identified by GdMRV with a sensitivity and specificity of 83% and 97% for the right hepatic vein, 86% and 100% for the main portal vein (MPV), 42% and 99% for the right portal vein, 54% and 94% for the left portal vein, 61% and 96% for the superior mesenteric vein, and 74% and 91% for the splenic vein. Varices and shunts were correctly identified with a sensitivity of 96%. Multiplanar reconstruction increased MPV sensitivity to 100%.

CONCLUSION

Vascular abnormalities that affect TIPS and OLT can be identified by GdMRV. Multiplanar reconstruction increased the accuracy to 100% for the MPV.

[A comparison study on the sensitivity of lung tumor short-term induction test in three strains of mice]

To compare the sensitivities of lung tumor short-term induction in different strains of mice, the carcinogenicity risk was evaluated with the incidence rate and the average number of tumors. Three different strains of mice (KM, BALB/c and A/J) were injected with a single different dose of urethane i.p. The results demonstrated that the lowest dose for increasing tumor risk was 100 mg/kg in KM, 200 mg/kg in BALB/c, and lower than 25 mg/kg in A/J strain. So, the sensitivity of A/J strain is the highest and that of BALB/c is the lowest.

[Changes in cerebral circulation function during head down bed rest for 7 days]

To further understand the effects and regulation of brain circulation before, during and after short-term -6 degrees head down bed rest (HDT), 6 healthy young men aged 19-21 years, were subjected to HDT for 7 d. Cerebral blood flow velocity in the middle cerebral arteries of both sides was measured with a TC2000TCD instrument in 6 young adults before, during, and after 7d HDT. The results showed that cerebral blood flow velocity in the middle cerebral arteries increased throughout HDT, the increase was obvious in 24 h. They reached the highest value at the 4th hour and the lowest value on the 5 th day, and then, there were a tendency to rise on the 6th day and 7th day. The changes were about the same on both sides.

A cross-cultural study of family and peer correlates of adolescent misconduct

Participants were 4 groups of early adolescents from middle-class backgrounds (European and Chinese Americans in southern California and Chinese in Taipei, Taiwan, and Beijing, China). The 591 adolescents (M age = 13.8 years) completed questionnaires about their involvement in misconduct and about family and peer characteristics. Mothers of a subsample of adolescents (n = 405) also completed a questionnaire about their relationships with their adolescents. The 4 groups of adolescents reported significantly different mean levels of family and peer correlates but showed strikingly similar levels and patterns of self-reported misconduct. Structural equation models revealed that 2 latent variables (family relationships and peer sanctions) accounted for more variance in misconduct among European and Chinese American adolescents (51%-62%) than among the 2 Chinese groups (15%-24%), mainly because of a greater contribution of peer factors in the former groups.

[A survey of prostate symptoms in old male population]

To know well the prostate symptoms in old men, the prostate symptom scores of 412 male residents over 60 years of age in Chengdu area (116 in city and 296 in countryside) were investigated by using I-PSS. The results showed that there was a significant difference between the city and countryside in terms of symptoms score(P < 0.05) and quality of life scores (P < 0.05). No significant difference was noted among the three age groups (P > 0.05). However, the mean score and the percentage of high score section in the elder group were higher than those in the younger group. The prevalence of benign prostate hypertrophy (BPH) and the demands on quality of life in city were different from those in countryside, and the prevalence rate of BPH increased with age.

[Effect of 7 d head down bed rest on cardiopulmonary circulation in human]

Changes of cardiopulmonary circulation in 6 healthy young men during 7 d head down bed rest (-6 degrees HDT) were observed with the XXH-2000 lesser circulation and cardiac function instrument. Decrease of Q-j and Q-j/j-z, increase of hz, hc, and hc/hz were found during the initial 24 h. After 24 h, j-z decreased and Q-j/j-z increased. The results showed that increased pulmonary arterial pressure, increased preload of left and right heart, increased right myocardial contractility and congestion of the lungs appeared during 24 h bed rest, after which right myocardial contractility decreased. It suggests that the lesser circulation and cardiac function testing is a sensitive method for evaluating the cardiopulmonary circulation function during HDT.

Vascular complications of liver transplantation: evaluation with gadolinium-enhanced MR angiography

PURPOSE

To evaluate use of gadolinium-enhanced magnetic resonance (MR) angiography in detection of vascular complications of liver transplantation.

MATERIALS AND METHODS

Thirteen liver transplant recipients suspected to have vascular complications were evaluated with gadolinium-enhanced MR angiography by using a three-dimensional spoiled gradient-echo breath-hold technique during the arterial and venous phases of a high-dose (42 mL) bolus injection of gadolinium contrast material. Conventional angiography (n = 11) and surgery (n = 3) were used as the standard of reference. The transplant hepatic artery, celiac trunk, superior mesenteric artery, portal vein, superior mesenteric vein, splenic vein, hepatic veins, and inferior vena cava (IVC) were evaluated for thrombosis or stenosis by two radiologists.

RESULTS

Ten vascular complications were identified with conventional angiography or surgery: transplant hepatic artery thrombosis (n = 3) or stenosis (n = 3), portal vein stenosis (n = 1) or occlusion (n = 2), and suprahepatic IVC stenosis (n = 1). All 10 complications were correctly diagnosed with MR angiography. There was agreement between results of MR angiography and conventional angiography or surgery in 58 of 62 vessels evaluated (94%). There was minor disagreement in four vessels (6%).

CONCLUSION

Three-dimensional gadolinium-enhanced MR angiography may have the potential to enable accurate diagnosis of vascular complications of liver transplantation.

A potential approach to antifertility vaccine by expression of sperm membrane peptide in Salmonella

A synthetic oligonucleotide, HSD-2a, encoding a peptide segment of the extracellular domain of a human sperm membrane protein, YWK-II, was inserted by blunt-end ligation at the EcoRV site in the hypervariable, antigenically determinant region IV of Salmonella flagellin gene fliC (d). The recombinant plasmid (pLS408-H1) was transferred into the nonpathogenic aroA live vaccine Salmonella dublin strain SL5928, which is flagellin-negative. Location of the HSD-2a protein on the surface of the flagella was demonstrated by ELISA and by immunogold-labeling electron microscopy using mouse anti-YWK-II antiserum. A 60 kD protein, corresponding to the chimeric flagellin, was isolated from the recombinant S. dublin and found to contain the expressed HSD-2a peptide determined by Western blot analysis using anti-YWK-II antiserum. The Salmonella strain carrying the recombinant plasmid-pLS408-H1 may thus be a potential source of antifertility vaccine.

Prognostic factors for survival of patients treated systemically for disseminated melanoma

PURPOSE

The current American Joint Commission on Cancer (AJCC) staging system distinguishes between soft tissue and visceral metastases in advanced (stage IV) melanoma. We sought to verify these staging criteria and to identify prognostic variables that could be used to evaluate the impact of systemic therapy on long-term survival during the prior decade.

PATIENTS AND METHODS

We conducted a retrospective study of patients with advanced cutaneous melanoma enrolled in clinical trials between 1979 and 1989 at The University of Texas M.D. Anderson Cancer Center. Pretreatment age, sex, number of organs with metastases, serum levels of lactate dehydrogenase (LDH) and albumin, and period of enrollment were analyzed using a Cox proportional hazards model of survival.

RESULTS

In univariate and multivariate analyses that involved 318 stage IV patients, normal serum levels of LDH and albumin, soft tissue and/or single visceral organ metastases (especially lung), female sex, and enrollment late in the decade were independent positive predictors for survival. In multivariate analyses, the current AJCC criteria did not significantly predict outcome. Systemic treatment response did not bias these results, and only 4% of patients had a complete response. Patients who lived more than 2 years (11%) had a mix of favorable prognostic characteristics and a high frequency of systemic or surgically induced complete response.

CONCLUSION

This study supports the use of stratification parameters that reflect the favorable prognostic impact of soft tissue or single visceral organ metastases and normal serum levels of LDH and albumin at time of enrollment in advanced melanoma trials. Improved survival over the prior decade probably reflects advances in diagnostic and palliative interventions.

Degradation of surfactant protein D by alveolar macrophages

Surfactant protein (SP) D is a pulmonary surfactant-associated protein that may function in lung host defense. SP-D is produced by alveolar type II cells and nonciliated bronchiolar epithelial (Clara) cells of the airway and is secreted into the air space. Here we investigated whether alveolar macrophages degraded SP-D in vitro. We also examined the effects of SP-A and lipids on SP-D metabolism. The results showed that alveolar macrophages bound and degraded SP-D in a time- and temperature-dependent fashion. After 100 min of incubation, the formation of trichloroacetic acid-soluble degradation products increased 4-fold in the medium and 30-fold in the cells. The degradation of SP-D was via a cell-associated process because SP-D was not degraded when incubated in medium previously conditioned by alveolar macrophages. Gel autoradiography of cell lysate samples after incubation with 125I-labeled SP-D demonstrated an increase in degradation products, further confirming the degradation of SP-D by alveolar macrophages. In addition, the degradation of SP-D was not affected by coincubation with SP-A or surfactant-like liposomes containing either phosphatidylglycerol or phosphatidylinositol. In conclusion, alveolar macrophages rapidly degrade SP-D and may play an important role in SP-D turnover and clearance.

Effect of retinol in preventing squamous cell skin cancer in moderate-risk subjects: a randomized, double-blind, controlled trial. Southwest Skin Cancer Prevention Study Group

We conducted a randomized, double-blind, controlled trial to examine the efficacy of retinol supplementation on the incidence of first new nonmelanoma skin cancer in moderate-risk subjects. A total of 2297 free-living subjects were enrolled; subjects resided in Arizona (median age, 63 years) and had a history of more than 10 actinic keratoses and at most 2 squamous cell carcinoma (SCC) or basal cell carcinoma (BCC) skin cancers. Subjects were randomly assigned to receive oral retinol (25,000 IU) or placebo supplementation daily for up to 5 years. The primary end points for the trial were time to first new SCC or BCC. During a median follow-up time of 3.8 years, we found that 526 subjects had a first new skin cancer. Comparing retinol-supplemented subjects with placebo-supplemented subjects showed a hazard ratio for first new SCC of 0.74 (95% confidence interval, 0.56-0.99; P = 0.04). The hazard ratio of first new BCC for the retinol-supplemented subjects compared with those receiving placebo was 1.06 (95% confidence interval, 0.86-1.32; P = 0.36). Potentially adverse symptoms that were judged to be associated with retinol were rare (approximately 1% higher in the retinol group than in the control group). Therefore, we concluded that daily supplementation with 25,000 IU of retinol was effective in preventing SCC, although it did not prevent BCC.

[Effect of Helicobacter pylori on gastric epithelial apoptosis]

To investigate the mechanisms by which Helicobacter pylori (Hp) induces gastric mucosal damage, gastric epithelial apoptotic index (AI) of normal gastric mucosa and Hp positive gastritis before and after anti-Hp treatment was studied with the method of terminal transferase mediated dUTP nick end labeling. The results showed that AI in Hp positive gastritis was higher than that in normal mucosa (P < 0.001). After the eradication of Hp, AI fell significantly to the normal level (P < 0.001). AI in persisting Hp positive gastritis had no statistically significant decrease after the anti-Hp treatment. There was no correlation between AI and the severity of gastritis. These results indicated that Hp could induce gastric epithelial apoptosis, which may be an important mechanism involved in gastric mucosal damage.

Trial of retinol and isotretinoin in skin cancer prevention: a randomized, double-blind, controlled trial. Southwest Skin Cancer Prevention Study Group

The objective of this study was to examine the effect of retinol and isotretinoin on the incidence of nonmelanoma skin cancer in high-risk subjects. A total of 525 participants with a history of at least four basal cell carcinomas (BCCs) and/or cutaneous squamous cell carcinomas (SCCs) were entered into a randomized, double-blind, placebo-controlled trial, performed in free-standing study clinics. Participants were randomly assigned to receive oral retinol (25,000 units), isotretinoin (5-10 mg), or placebo supplementation daily for 3 years. The time to first new occurrence of BCC or cutaneous SCC was used as the outcome measure. During the study period, 319 BCCs and 125 cutaneous SCCs were diagnosed clinically and pathologically. There were no differences between those who received retinol, isotretinoin, or the placebo, with regard to the time to first occurrence or to the total number of tumors noted. No beneficial effects were noted with regard to the prevention of nonmelanoma skin cancer with either retinol or isotretinoin.

Erythrocyte deformation in simulated weightless human and rabbits

Effect and mechanism of simulated weightlessness (SWL) in humans and rabbits erythrocyte deformation were studied. Erythrocyte deformation and membrane fluidity in humans and rabbits, and erythrocyte morphology and hemorreology indices in control and HDT rabbits were measured. The results were a decrease in erythrocyte deformation and membrane fluidity in humans and rabbits during SWL, a significant increase in abnormal erythrocyte, blood viscosity, hematocrit, fibrinogen, and red blood cell aggregation index in HDT rabbits. These results show that the changes in erythrocyte shape, increase of erythrocyte internal viscosity and changes in erythrocyte visco-elasticity may be causing the decrease of erythrocyte deformation in SWL humans and rabbits.

[Experimental study on supraeruption of the unopposed miniature pig molars]

Supraeruption of the molars in the absence of antagonist molars or without occlusal contacts was observed in a miniature pig. Tetracycline was used to label the new regenerated cementum and alveolar bone associated with the supraeruption. The results showed that the molar through root canal treatment migrated the same level as the molars with pulp, which means that the hydrodynamic and hydrostatic forces arising from the blood in pulp vessels look doubtful. Cementum and alveolar bone deposition was seen around the apical, cervical regions and under the furcation area. The thickness of the deposition layers was almost the same as the supraerupted volume from the model measurement.

[Primary study on the sensitivity of cytokinesis blocked micronucleus assay in CHL cells]

Studies were performed to determine the cytochalasin B induced binucleated cell percentage influenced by clastogens and aneuploidgens and to compare the efficacy of cytokinesis blocked binucleated cells for scoring micronuclei with that of the conventional mononucleated method following the treatment with mitomycin C, methyl methanesulforate, colchicin and chloral hydrate. The results showed that mitomycin C decreased the binucleated cell percentage induced by cytochalasin B, whereas colchicin increased the frequencies of binucleated cells. The frequencies of micronuclei in binucleated cells were not significantly higher than those in the conventional mononucleated cells. The results suggest that cytokinesis blocked method is not more sensitive than the conventional method for scoring micronuclei. The factors that may influence the cytokinesis blocked micronucleus assay have been discussed.

Effects of simulated weightlessness on erythrocyte deformability in rats

In order to investigate the mechanism of space anemia, the erythrocyte deformability membrane fluidity and cell shape in 7, 15, 30 day tail-suspended rats were observed. The results were: (1) erythrocyte deformability (DImax and IDI) in suspended rats was significantly lower than that in the control on the 7th day (P<0.05), and had a further decrease on the 15th day (P<0.01), but a recovery was found on the 30th day (P<0.05). (2) membrane fluidity in suspended rats was markedly lower than that in the control group on the 15th and 30th day, degrees of fluorescence polarization was increased (P<0.01), but there was no change on the 7th day. (3) percentage of erythrocytes with abnormal shape in suspended rats was higher than that in the control group during the whole experimental period. The results indicate that the changes of rheological and morphological properties of red cell were induced by simulated weightlessness (SWL), which may be an important cause of space anemia.

Methylator resistance mediated by mismatch repair deficiency in a glioblastoma multiforme xenograft

A methylator-resistant human glioblastoma multiforme xenograft, D-245 MG (PR), in athymic nude mice was established by serially treating the parent xenograft D-245 MG with procarbazine. D-245 MG xenografts were sensitive to procarbazine, temozolomide, N-methyl-N-nitrosourea, 1,3-bis(2-chloroethyl)-1-nitrosourea, 9-aminocamptothecin, topotecan, CPT-11, cyclophosphamide, and busulfan. D-245 MG (PR) xenografts were resistant to procarbazine, temozolomide, N-methyl-N-nitrosourea, and busulfan, but they were sensitive to the other agents. Both D-245 MG and D-245 MG (PR) xenografts displayed no O6-alkylguanine-DNA alkyltransferase activity, and their levels of glutathione and glutathione-S-transferase were similar. D-245 MG xenografts expressed the human mismatch repair proteins hMSH2 and hMLH1, whereas D-245 MG (PR) expressed hMLH1 but not hMSH2.

Age and gender differences in the self-esteem of Chinese children

A Chinese version of the Self-Description Questionnaire 1 (SDQ-1; Marsh, 1988) was used to investigate age and gender differences in a sample of 303 male and 296 female 10-year-old children and 116 male and 116 female 13-year-old children attending typical Beijing public schools. Significant Age x Gender interaction effects were found on all 8 SDQ-1 scales. Main effects for age were found on the Physical Abilities, Reading, and School subscales and for gender on the same three subscales plus Peer Relations. Further analysis indicated that the older girls tended to report significantly lower self-esteem than both the younger girls and older boys in the areas of physical abilities, reading, mathematics, and general self-concept. The boys reported more positive self-perceptions on most nonacademic self-scales, but both the older boys and older girls reported less favorable self-esteem than their younger peers on the scales for reading and school in general.