The development and characterization of an HEK293-derived cell line for use in an intratumoral cytokine delivery system

As part of ongoing work to develop a method of cytokine delivery for use as an intratumoral depot, we noted that HEK293 cells, encapsulated in alginate, died within 24-48 h after in vivo, intratumoral implantation. We hypothesized that the highly hypoxic and acidic conditions found inside the tumor was the cause of the cells' premature demise. Therefore, we set out to develop a cell line, derived from HEK293, that would survive these hostile conditions. The HEK293 line was selected in 0.3-0.5% oxygen conditions over several weeks, followed by a further 6-week period of culture in alternating hypoxic and normoxic conditions. The most rapidly growing clones were selected and grown in normoxic conditions for several weeks to ensure their stability. The clones were then compared to the original line in terms of cell proliferation in normoxia and hypoxia, colony-forming efficiency, and morphological characteristics. The resulting line was able to proliferate in the harshest of conditions and continues to release its biological payload after alginate microencapsulation.

Comparative evaluation of the cerebral state index and the bispectral index during target-controlled infusion of propofol

BACKGROUND

Cerebral state index (CSI) has recently been introduced as an intra-operative monitor of anaesthetic depth. We compared the performance of the CSI to the bispectral index (BIS) in measuring depth of anaesthesia during target-controlled infusion (TCI) of propofol.

METHODS

Twenty Chinese patients undergoing general anaesthesia were recruited. CSI and BIS, and predicted effect-site concentration of propofol were recorded. The level of sedation was tested by Modified Observer's Assessment of Alertness/Sedation Scale (MOAAS) every 20 s during stepwise increase (TCI, 0.5 microg ml(-1)) of propofol. The loss of verbal contact (LVC) and loss of response (LOR) were defined by MOAAS values of 2-3 and less than 2, respectively. Baseline variability and the prediction probability (P(K)) were calculated for the BIS and CSI. The values of BIS(05) and CSI(05), BIS(50) and CSI(50), BIS(95) and CSI(95) were calculated at each end-point (LVC and LOR).

RESULTS

Baseline variability of CSI was more than that of BIS. Both CSI and BIS showed a high prediction probability for the steps awake vs LVC, awake vs LOR, and LVC vs LOR, and good correlations with MOAAS values.

CONCLUSION

Despite larger baseline variation, CSI performed as well as BIS in terms of P(K) values and correlations with step changes in sedation.

Highly photoluminescent multilayer QD-glass films prepared by LbL self-assembly

A novel and facile preparation method for layer-by-layer (LbL) self-assembled films incorporating quantum dots (QDs) and having intense photoluminescence (PL) from blue to red is presented. Functional sol-gel-derived glass layers prepared by the hydrolysis of 3-aminopropyltrimethoxysilane (APS) or 3-mercaptopropyltrimethoxysilane (MPS) have been used as a linkage between QD layers. Absorption, PL spectroscopy, transmission electron microscopy, and atomic force microscopy were employed for characterization, which revealed that the QDs in the prepared films had a nearly close-packed coverage and were not aggregated. The PL efficiencies of the QDs (CdTe or ZnSe, both are thioglycolic acid-stabilized) dispersed in the films were roughly half that of the initial colloidal solutions but reached 24% before a refractive index correction. The thickness of the red-emitting film with 10 CdTe QD layers was approximately 50 nm. The concentration of QDs in the film derived from the first absorption peak was approximately 0.01 M. Because the PL starts to show a red shift, the obtained concentration is practically the ultimate one in the glass matrix. The mercapto, amino, and carboxyl groups play important roles in LbL self-assembling processes.

Quantitative Analysis of the Photodegradation of Emitting CdTe Nanocrystals Dispersed in Glass Films

CdTe nanocrystals (NCs, green- and red-emitting) prepared by an aqueous method were embedded into transparent glass films (15-20 microm thick) using a sol-gel method. Photodegradation of the NCs in the films due to UV irradiation (365 nm) was investigated quantitatively by measuring the PL efficiency as a function of the irradiation time for various irradiation intensities at several temperatures. Since CdTe NCs prepared by an aqueous method incorporate sulfur atoms from the surfactant (thioglycolic acid) during prolonged reflux in an alkaline region, the surface of red-emitting NCs (3.9 nm phi) is much more sulfur rich than that of green-emitting ones (2.6 nm phi), as previously reported. Due to this composition difference, the degradation behaviors of the two types of NCs differ significantly. The photodegradation of green-emitting glass films depended linearly on the irradiation intensity, whereas that of red-emitting ones showed a quadratic dependence. The activation energies of the photodegradation for both types of films were similar, 304 +/- 9 and 288 +/- 7 meV/particle, respectively. The NCs in the film were more than 2 orders of magnitude more robust than those in colloidal solutions. Comparison of the degradation of the glass films in air and in an Ar atmosphere revealed that the main mechanism of the photodegradation of the green-emitting NCs was oxidization from the first electronically excited state. The mechanism of the red-emitting NCs was not oxidization but a surface change probably related to a surfactant reaction.

Enhanced oral bioavailability of breviscapine after encapsulation in a liposomal formulation

This report firstly describes the pharmacokinetic study of liposomal breviscapine (LB) after oral administration in rats. The mean Cmax and AUC(0-->t) of LB were 3.3 and 3.1-fold higher than those of breviscapine solution (BS). The oral absorption of breviscapine was significantly increased after encapsulation in the liposomal formulation.

A comparison of urinary albumin excretion rate and microalbuminuria in various glucose tolerance subjects

AIMS

To investigate the difference of urinary albumin excretion rate (UAER) and microalbuminuria (MAU) in various glucose tolerance subjects, especially between isolated-impaired glucose tolerance subjects and isolated-impaired fasting glycaemia subjects.

METHODS

A total of 2934 subjects were divided into five groups with various glucose tolerances, based on a 75-g oral glucose tolerance test. Microalbuminuria was defined when urinary albumin excretion rate was between 20 and 200 microg/min.

RESULTS

(i) The UAER in the newly diagnosed Type 2 diabetes mellitus group, impaired glucose tolerance/impaired fasting glycaemia group and isolated-impaired glucose tolerance group were all higher than that in the isolated-impaired fasting glycaemia group and normal glucose tolerance group, but it was comparable between isolated-impaired fasting glycemia group and normal glucose tolerance group. The prevalence of MAU and the odds ratio for MAU with adjustment for age and sex in various glucose tolerance groups showed the same trend as the UAER. (ii) After adjusting for age and sex, there is a significant association between logUAER and independent risk factors (partial correlation coefficients: r = 0.26 for 2-h post-challenge blood glucose, r = 0.26 for systolic blood pressure, r = 0.27 for diastolic blood pressure, r = 0.27 for body mass index and r = -0.13 for high density lipoprotein-cholesterol, all P < 0.001). The risks for MAU were 2-h post-challenge blood glucose, body mass index and diastolic blood pressure, while high density lipoprotein-cholesterol was protective.

CONCLUSIONS

The urinary albumin excretion rate and prevalence of microalbuminuria were higher in isolated-impaired glucose tolerance subjects than those in isolated-impaired fasting glycaemia subjects. At early abnormal glucose tolerance stage, the increasing post-challenge glycaemia might be a more important risk factor for urinary albumin excretion rate and microalbuminuria than increasing fasting glycaemia.

Sentinel lymph node biopsy in breast cancer patients after overnight migration of radiolabelled sulphur colloid

OBJECTIVE

To evaluate the performance and feasibility of sentinel lymph node biopsy in breast cancer patients using technetium-99m (99mTc) sulphur colloid and gamma probe.

METHODS

From May 2000 to March 2001, 70 patients with a tumour less than 5 cm with clinically negative axillary lymph nodes underwent sentinel node biopsy followed by standard axillary dissection. 99mTc sulphur colloid was injected around the primary tumour the day before surgery and a gamma probe was used to detect the sentinel lymph node during the surgical procedure. Sentinel lymph node biopsy was compared with standard axillary dissection for its ability to accurately reflect the final pathological status of the axillary nodes.

RESULTS

The sentinel lymph node was successfully identified in 67 of 70 patients (95.71%). The number of sentinel lymph nodes ranged from 1-5 (mean 1.5) and non-sentinel nodes ranged from 5-22 (mean 13.3). Of the 67 patients with successfully identified sentinel lymph nodes, 43.28% (29/67) were histologically positive. Sensitivity of the sentinel lymph node to predict axilla was 82.75%; specificity was 100%. Positive and negative predictive values were 100% and 88.3% respectively. The sentinel lymph node was falsely negative in five patients, yielding an accuracy of 92.53%. Sentinel lymph node biopsy was more accurate for T1 tumours than for T2 tumours.

CONCLUSIONS

The gamma probe guided method after overnight migration of 99mTc sulphur colloid is technically feasible for detecting sentinel lymph nodes in most breast cancer patients, accurately predicting the axillary lymph node status, and appears more accurate for T1 lesions than for larger lesions. This minimally invasive axillary staging procedure represents a major advance in the surgical treatment of breast cancer.

Ciliary neurotrophic factor injected icv induces adipose tissue apoptosis in rats

Recent findings show that ciliary neurotrophic factor (CNTF) and leptin have similar effects on food intake and body weight, suggesting possible overlapping mechanisms. Intracerebroventricular (icv) injection of leptin results in adipose tissue apoptosis. To determine if CNTF has similar activity, male Sprague Dawley rats implanted with lateral cerebroventricular cannulas were randomly assigned to four treatment groups ( N = 8), including control (aCSF), 10 microg/day leptin, 1 microg/day CNTF, and 5 microg/day CNTF. Rats received daily icv injections for 4 successive days. Both leptin and CNTF (5 microg) decreased BW (8.6% and 11.77%, respectively, p <.05) and cumulative food intake was decreased 43% by leptin ( p <.05). Leptin and CNTF (5 microg) reduced adipose tissue mass in epididymal adipose (Epi) by 30 and 33.5%, ( p <.05), in inguinal adipose (Ing) by 51 and 55% ( p <.05), in retroperitoneal adipose (Rp) by 65 and 64% ( p <.05), and in intrascapular brown adipose (iBAT) by 34 and 25% ( p <.05), respectively. Gastrocnemius muscle was not affected. Leptin and CNTF (5 microg) increased apoptosis in Epi by 84 and 150%, respectively ( p <.05) and in Rp by 121 and 146%, respectively ( p <.05). Loss of adipocytes by apoptosis may provide an explanation for the unexpected delay in return to initial energy status following CNTF treatments.

Anatomical study on the morphology and blood supply of the falciform ligament and its clinical significance

The purpose of this study was to understand the clinical significance of the morphology and blood supply of the falciform ligament in laparoscopic surgery. The structure, blood vessel distribution and anastomoses of the falciform ligament were observed in 20 cases of living laparoscopy, 30 cadaveric specimens injected with latex and five cadaveric specimens with Indian ink and hyaline. The falciform ligament was formed by two sides of peritoneum and its length, largest and smallest width were 8.3+/-1.6 cm, 4.9+/-0.8 cm and 1.1+/-0.3 cm, respectively. The left inferior phrenic artery and middle segment artery of the liver formed a vessel that arched and gave off 6-12 branches to the falciform ligament. The veins of the falciform ligament drained into the left inferior phrenic vein, and were not accompanied by any artery. In conclusion, the vessels of the falciform ligament anastomose with multiple vessels and form a significant pathway of the collateral circulation in the liver. The falciform ligament is an important landmark in laparoscopic surgery.

[Clonning and identification of the gene encoding specific IgE antibody-related antigen of Schistosoma japonicum]

OBJECTIVE

To obtain the gene encoding specific IgE-related antigen of Schistosoma japonicum from the cDNA library of adult Schistosoma japonicum.

METHODS

The pooled sera from 15 individuals with high levels of specific IgE antibody against SWAP were absorbed with Protein-G and used for screening of IgE-related antigen from the adult worm cDNA library of Schistosoma japonicum. The inserted cDNA was amplified by PCR and sequenced. According to the first reading frame of the sequence, a pair of new probes, in which EcoR I and Not I sites were incorporated respectively, were designed and used to amplify the target gene. Then, the gene was cloned into vector pGEM-T and subcloned into expression vector pGEX-6p-1. The fusion protein was expressed, analysed by SDS-PAGE and identified by Western blotting with the specific IgE antibody, respectively.

RESULTS

The inserted cDNA fragment from the positive clone was about 1,200 bp, with the ORF of 507 bp which encoded 169 amino acids. The deduced molecular weight of the recombinant protein was 19.3 kDa. The homology between the target gene (Sj43B) and other known DNA sequences was less than 40%. The fusion protein expressed by the recombinant vector pGEX-6p-1/Sj43B could be recognized by schistosome specific IgE antibody.

CONCLUSION

Sj43B may encode the specific IgE-related antigen of Schistosoma japonicum. The successful construction of recombinant plasmid pGEX-6p-1/Sj43B lay the groundwork for further studies on immunological characteristics and protection immunity of the recombinant protein.

Bone marrow-derived stem cells and "plasticity"

Studies describing plasticity of somatic stem cells have become a focus of interest because clinical applications in the treatment of degenerative diseases would be at hand. In particular, bone marrow-derived cells and their potential to contribute to skeletal and cardiac muscle, liver, neurons and epithelium have recently been studied extensively. Nevertheless, results of these studies have not always been consistent with each other, and yet it remains to be resolved whether plasticity of adult stem cells truly exists. This review will discuss the role of bone marrow-derived stem cells in the field of experimental and clinical plasticity studies. Observations compatible with the concept of stem cell plasticity will be weighed against limitations of the experimental systems employed.

A role for CCN3 (NOV) in calcium signalling

AIMS

In animals and humans increased expression of CCN3 (NOV) is detected in tissues where calcium is a key regulator, such as the adrenal gland, central nervous system, bone and cartilage, heart muscle, and kidney. Because the multimodular structure of the CCN proteins strongly suggests that these cell growth regulators are metalloproteins, this study investigated the possible role of CCN3 in ion flux and transport during development, control of cell proliferation, differentiation, and pathobiology.

METHODS

The isolation of CCN3 partners was performed by means of the two hybrid system. Yeasts were cotransfected with an HL60 cDNA library fused to the transactivation domain of the GAL4 transcription factor, and with a plasmid expressing CCN3 fused to the DNA binding domain of GAL4. Screening of the recombinant clones selected on the basis of leucine, histidine, and tryptophan prototrophy was performed with a beta-galactosidase assay. After the interaction between CCN3 and its putative partners was checked with a GST (glutathione S-transferase) pull down assay, the positive clones were identified by cloning. To establish whether the CCN3 protein affected calcium ion flux, a dynamic imaging microscopy system was used, which allowed the fluorometric measurement of the intracellular calcium concentration. The proteins used in the assays were GST fused with either CCN3 or CCN2 (CTGF) and GST alone as a control.

RESULTS

The two hybrid system identified the S100A4 (mts1) calcium binding protein as a partner of CCN3 and the use of the GST fusion proteins showed that the addition of CCN3 and CCN2 to G59 glioblastoma and SK-N-SH neuroblastoma cells caused a pronounced but transient increase of intracellular calcium, originating from both the entry of extracellular calcium and the mobilisation of intracellular stores.

CONCLUSIONS

The interaction of CCN3 with S100A4 may account, in part, for the association of CCN3 with carcinogenesis and its pattern of expression in normal conditions. The increased intracellular calcium concentrations induced by CCN3 and CCN2 both involve different processes, among which voltage independent calcium channels might be of considerable importance in regulating the calcium flux associated with cell growth control, motility, and spreading. These observations assign for the first time a biological function to the CCN3 protein and point out a broader role for the CCN proteins in calcium ion signalling.

[Analysis of succeed percentage on sequencing ESTs and construction of porcine muscle cDNA library]

Using Longissimus Dorsi muscle as material and Lambda ZAP II as Vector, Xiang Pig Longissimus Dorsi muscle cDNA library has been constructed in our study. The results showed that the titration of the library was 3.4 x 10(7) pfu/ml, the recombinant percentage was 94%, and the fragment length of inserted average cDNA were 1.5 kb. The study pointed out that the more than 30 T insertion is the major factor for low percentage if sequencing the 3'-end.

Identification and characterization of mutations underlying Sanfilippo syndrome type A (mucopolysaccharidosis type IIIA)

Sanfilippo syndrome type A (mucopolysaccharidosis type IIIA; MPS IIIA) is caused by a deficiency of the lysosomal enzyme haparan N-sulphatase (NS). The genomic DNA segments of the NS gene from two Chinese patients with MPS IIIA were amplified by polymerase chain reaction, followed by DNA sequencing to study the molecular lesions. Four mutations (i.e. N42K, D235N, P293S and R377C) and five polymorphisms (i.e. IVS2-72A --> G, IVS2-26T --> C, IVS5+17C --> T, IVS5-37GC --> CTGT and R456H) were identified. Transfection of COS-7 cells with cDNA mutagenized to the corresponding mutations did not yield active enzyme, demonstrating the deleterious nature of the mutations. Western blot analysis revealed a 62-kDa precursor and 56-kDa mature forms for cells transfected with wild-type and polymorphic R456H enzymes. For cells transfected with mutant enzymes, the reduction in precursor and mature forms suggests an increased degradation of the mutant enzymes. The polymorphic DNA haplotype of the NS gene was analysed in 52 unrelated subjects. All five polymorphisms were in Hardy-Weinberg equilibrium. The strong non-random association among the five polymorphisms suggests little or no recombination in the NS gene.

Heat shock inhibits IL-12 p40 expression through NF-kappa B signalling pathway in murine macrophages

We report the effect of heat shock on lipopolysaccharide (LPS)-induced interleukin 12 (IL-12) expression. The augmentation of LPS-induced IL-12 p40 mRNA and p70 protein was significantly suppressed in both peritoneal macrophages and RAW264.7 cells after heat shock at 43 degrees C. The binding activity of nuclear factor kappa B (NF-kappa B) was reduced by prior heat shock. LPS did not induce degradation of the inhibitory protein I-kappa B alpha in the shocked cells, which might be a potential mechanism to block NF-kappa B activation. Furthermore, transient transfection assay in RAW264.7 cells demonstrated that LPS-induced activation of DM703 and DM138 (contains NF-kappa B motif) was highly sensitive to heat shock. These data suggest that heat shock influences expression of IL-12 through the I-kappa B/NF-kappa B pathway.

Epidemiology of type 2 diabetes in Taiwan

In the face of the growing worldwide prevalence of type 2 diabetes, effective methods of preventing further increases in prevalence are needed. In this paper, we review the community-based epidemiologic studies of diabetes in Taiwan published during the last decade, and look at the effectiveness of a two-stage screening protocol for identifying subjects at risk for progression to type 2 diabetes. The results of these studies indicate that the age-adjusted prevalence rate of undiagnosed diabetes in Taiwan is stable, at around 4.0%, while the annual incidence rate is about 1.8%. The results of several studies strongly suggest that a two-step screening strategy, in which only subjects with a fasting plasma glucose level of 5.6-7.8 mmol/l receive the oral glucose tolerance test, may be an effective means of identifying diabetics and persons at high risk for progression to type 2 diabetes and, ultimately, slowing the increase in the prevalence of this disease.

Tetracaine topical anesthesia for myringotomy

OBJECTIVES/HYPOTHESIS

To study the efficacy and safety of topical tetracaine anesthesia for office myringotomy and myringotomy with a tube.

STUDY DESIGN

Retrospective review of patients undergoing office myringotomy, with or without tube insertion, performed over a 4-year period.

METHODS

A topical solution of 8% tetracaine base in 70% isopropyl alcohol was used in 381 ears. Five to 10 drops of the solution were applied to the tympanic membrane for 10 to 15 minutes and aspirated. Myringotomy was performed either with a myringotomy knife or with a CO(2) laser (OtoLAM).

RESULTS

Topical tetracaine was used in all 231 ears (100%) undergoing myringotomy without a tube and 150 of 212 ears (71%) undergoing myringotomy with a tube. Tetracaine alone was effective in providing tympanic membrane anesthesia in 95% of myringotomy without a tube (220 ears) and in 93% of myringotomy with a tube (139 ears). There were six complications, including five cases of severe vertigo and one unusual prolonged, transient facial nerve weakness.

CONCLUSION

Topical tetracaine is efficacious and safe for use in office myringotomy.

Functional heterogeneity within rhodamine123(lo) Hoechst33342(lo/sp) primitive hemopoietic stem cells revealed by pyronin Y

OBJECTIVE

The aim of this study was to determine the function of primitive hematopoietic stem cells (PHSC) at phases G(0) and G(1) of the cell cycle.

MATERIALS AND METHODS

A combination of supravital dyes rhodamine123 (Rh), Hoechst33342 (Ho), and pyronin (PY) was used to isolate the G(0) and G(1) subsets of PHSC. A competitive repopulation assay was used to evaluate their in vivo function.

RESULTS

We confirmed that the Rh(lo)Lin(-)Kit(+)Sca-1(+) PHSC were relatively quiescent when compared with the more mature Rh(hi)Lin(-)Kit(+)Sca-1(+) HSC and Rh(hi)Lin(-)Kit(+)Sca-1(-) progenitors. In addition, cells with Rh(lo)Lin(-)Kit(+)Sca-1(+), Rh(lo)Ho(lo)Lin(-)Sca-1(+), or Rh(lo)Ho(sp)Lin(-)Sca-1(+) phenotypes identified the same cell population. We further subfractionated the Rh(lo)Ho(lo/sp)Lin(-)Sca-1(+) PHSC using PY into PY(lo) and PY(hi) subsets. Limiting dilution analysis revealed that the frequency of long-term in vivo competitive repopulating units (CRU) of the PY(lo)Rh(lo)Ho(lo/sp) PHSC was 1 in 10 cells, whereas there was at least a three-fold lower frequency in those isolated at the G(1) phase (PY(hi)). We found a dose-dependent PY-mediated cytotoxicity that at moderate concentration affected most of the murine hematopoietic compartment but spared the early HSC compartment.

CONCLUSION

Our data confirm that the HSC compartment is hierarchically ordered on the basis of quiescence and further extend this concept to PY-mediated cytotoxicity. PY supravital dye can be used to reveal functional heterogeneity within the Rh(lo)Ho(lo/sp) PHSC population but is of limited use in dissecting the relatively more mature hematopoietic stem/progenitor cell population.

Highly activated Fgfr3 with the K644M mutation causes prolonged survival in severe dwarf mice

Several gain-of-function mutations in a receptor tyrosine kinase, fibroblast growth factor receptor 3 (FGFR3), cause dwarfism in humans. Two particularly severe dwarfisms, thanatophoric dysplasia type II (TDII) and severe achondroplasia with developmental delay and acanthosis nigricans (SADDAN), are associated with glutamic acid (E) and methionine (M) substitutions at the K650 residue in the kinase domain. TDII is lethal at birth, whereas most of the SADDAN patients survive the perinatal period. However, FGFR3 with the SADDAN mutation is more activated than FGFR3 with the TDII mutation in vitro. To find out whether the K650M mutation also causes the SADDAN phenotype, we introduced the corresponding point mutation (K644M) into the mouse Fgfr3 gene. Heterozygous mutant mice show a phenotype similar to human SADDAN, e.g. the majority of the SADDAN mice survive the perinatal period. This suggests that the survival of SADDAN patients is indeed attributed to the K650M mutation in FGFR3. The long bone abnormalities in SADDAN mice are milder than the TDII model. In addition, overgrowth of the cartilaginous tissues is observed in the rib cartilage, trachea and nasal septum. The FGF ligand at the low concentration differentially activates Map kinase in primary chondrocyte cultures from wild-type and SADDAN mice. Comparisons of the molecular bases of the phenotypic differences in SADDAN and TDII mice may increase our understanding of the factors that influence the severity in these two related skeletal dysplasias.

[Histological evaluation of the biocompatibility of PDLLA membranes]

OBJECTIVE

To evaluate the histological response and biocompatibility of implanted domestic bio-degradable PDLLA membranes in vivo.

METHODS

The domestic biodegradable PDLLA membranes and non-degradable ePTFE membranes were in pairs placed subcutaneously in surgical incision made in the dorsum of rats. The tissue responses to these materials were observed histologically at 1, 2, 4, 8 and 12 weeks after placement.

RESULTS

The tissue responses of the two kinds of materials were similar to the non-specific reaction mainly infiltrated with lymphocytes, plasmocytes, macrophages, and foreign body giant cells. The polymorphonuclears and foreign body giant cells infiltrated round the ePTFE membranes existed for a relatively long period, in contrast to that of PDLLA membranes.

CONCLUSION

Domestic PDLLA membranes with good biocompatibility will be adapted to making GTR into a single step procedure.

Mutations of PTEN/MMAC1 in primary prostate cancers from Chinese patients

PTEN/MMAC1 is a putative tumor suppressor gene located on 10q23, one of the most frequently deleted chromosomal regions in human prostate cancer. Although mutations of PTEN have often been detected in metastases of prostate cancer, localized tumors have shown lower rates of mutation, which have varied from 0 to 20% among different studies. It is unknown whether the rate of PTEN mutations is different in prostate cancer from Asian men compared with Western men. To further clarify the role of PTEN in prostate cancer and to examine the gene for mutations in Asian men, we analyzed 32 cases of primary prostate cancers from Chinese patients, each of whom was not diagnosed by screening with serum prostate-specific antigen, for PTEN mutations using the methods of tissue microdissection, single-strand conformational polymorphism, and direct DNA sequencing. Seventy % of the tumors were Gleason scores 8-10, whereas the remainder were Gleason score 7. Six metastases of prostate cancer from American patients were also analyzed. Five of 32 (16%) primary prostate cancers from Chinese men and two of six metastases from American men showed mutations in a total of 10 codons of PTEN, which involved exons 1, 2, 5, 8, and 9. Two of the mutations were truncation type, whereas the rest were missense mutations. The mutation frequency in these cases from Asian patients was higher than that in our previous study of cases in radical prostatectomy specimens from American men, in which the 40 primary tumors were lower grade and had been detected by serum prostate-specific antigen test. We conclude that mutation of PTEN occurs more often in primary prostate cancers of Chinese men, whose tumors are high grade and reflective of an unscreened population.

Oral bioavailability and pharmacokinetics of elimination of 9-hydroxybenzo[a]pyrene and its glucoside and sulfate conjugates after administration to male and female American lobsters, Homarus americanus

The pharmacokinetics of [(3)H]-9-hydroxybenzo[a]pyrene (9-OH-BaP), a highly lipophilic primary metabolite of benzo(a)pyrene, were examined after intrapericardial (iv) or oral doses of 50 or 200 microg/kg to intermolt American lobsters, Homarus americanus. Combining data for all lobsters, the average terminal elimination half-life of parent 9-OH-BaP was 97.3 h after iv and 56.5 h after oral administration, considerably less than found previously for benzo(a)pyrene (720 h). The oral bioavailability of parent 9-OH-BaP, calculated from the area under the hemolymph concentration curve, was 15.9%. The low bioavailability and variable elimination rates were attributed to extensive first-pass conjugation and sequestration in the hepatopancreas. BaP-9-sulfate was the major metabolite. Hemolymph concentrations of BaP-9-sulfate increased up to one day after the dose, and then decreased, with a terminal elimination half-life of 45 h. BaP 9-beta-D-glucoside was a minor metabolite in most hemolymph and tissue samples; an exception was hemolymph from the iv high-dose group. Concentrations of 9-OH-BaP and metabolites in the edible muscle tissue were similar to those in hemolymph, and 9-OH-BaP residues at 10 to 16 days after the dose were 3 to 12 ng/g muscle. Sulfotransferase and UDP-glucosyltransferase (UGT) activities with 9-OH-BaP were found in the antennal gland, intestinal mucosa, and hepatopancreas (UGT only). Sulfatase activity with BaP-9-sulfate, found in both the hepatopancreas and the antennal gland, was thought to contribute to metabolite cycling. These studies showed that 9-OH-BaP was readily conjugated to sulfate and glucose in the lobster, and that despite their high lipophilicity, 9-OH-BaP and conjugates were excreted from the lobster hemolymph and tissues much more rapidly than benzo[a]pyrene.