Localization of pms3, a gene for photoperiod-sensitive genic male sterility, to a 28.4-kb DNA fragment

Photoperiod-sensitive genic male-sterile (PSGMS) rice, in which pollen fertility is regulated by day-length, originally arose as a natural mutant in the rice cultivar Nongken 58 (Oryza sativa ssp. japonica). Previous studies identified pms3 on chromosome 12 as the locus of the original PSGMS mutation. In this study we have assigned the pms3 locus to a 28.4-kb DNA fragment by genetic and physical mapping. A cross between Nongken 58S (PSGMS line) and DH80 was used to produce an F2 population of about 7000 plants, from which 892 highly sterile individuals were obtained for recombination analysis. By analyzing recombination events in the sterile individuals using a total of 157 RFLP probes from a BAC contig covering the pms3 region, the pms3 locus was localized to a sub-region of less than 1.7 cM. Further analysis of recombination events using 49 additional probes isolated from this sub-region identified markers flanking the pms3 region on each side; these markers are only 28.4-kb apart. Sequence analysis of this fragment predicted the presence of five ORFs, found high homology with two ESTs in public databases, and detected three SNPs between the mutant and the wild-type parents, which may be helpful for identifying a candidate gene for pms3.

Dentin matrix protein 1 expression during osteoblastic differentiation, generation of an osteocyte GFP-transgene

Our previous studies have demonstrated that promoter-green fluorescent protein (GFP) transgenes can be used to identify and isolate populations of cells at the preosteoblastic stage (pOBCol3.6GFP) and at the mature osteoblastic stage (pOBCol2.3GFP) in living primary bone cell cultures. This strategy forms the basis for appreciating the cellular heterogeneity of lineage and relating gene function to cell differentiation. A weakness of this approach was the lack of a selective marker for late osteoblasts and mature osteocytes in the mineralized matrix. In this study, we have examined the expression of DMP-1 mRNA in murine marrow stromal and calvarial osteoblast cultures, and in bone, and calvaria in vivo. Furthermore, we have generated transgenic mice utilizing a mouse DMP1 cis-regulatory system to drive GFP as a marker for living osteocytes. Transgene expression was directed to mineralized tissues and showed a high correlation with the expression of the endogenous gene. Osteocyte-restricted expression of GFP was observed in histological sections of femur and calvaria and in primary cell cultures. Generation of this transgenic model will facilitate studies of gene expression and biological functions in these terminally differentiated bone cells.

Upregulation of Fas and FasL expression in testosterone-induced apoptosis of macrophages

To the best of the authors' knowledge, there have been few reports on the effect of testosterone on the apoptosis of macrophages. In this report, we studied the effect of testosterone on the apoptosis of bone marrow-derived macrophages (BMMs) and the function of the Fas/Fas ligand (FasL) system in the process. Results showed that testosterone treatment in vitro at the physiological concentration of 10 nM did not induce the apoptosis of BMMs. However, BMMs underwent apoptosis when treated at higher concentrations of testosterone (100, 200 and 400 nM). Testosterone-induced apoptosis was associated with the enhanced expression of Fas, FasL, and caspase-8. These data suggest that the Fas/FasL system may play an important role in the testosterone-induced apoptosis of macrophages.

Mobilized blood cells vs bone marrow harvest: experience compared in 171 donors with particular reference to pain and fatigue

This prospective study compared the donor experience of blood cell (BC) mobilization and leukapheresis (n=116) with that of bone marrow (BM) harvest (n=55). Internal jugular catheters were inserted electively in 89% of BC donors. Most (80%) BM donors had a harvest with general anesthesia; 20% had epidural or spinal anesthesia. Pain and fatigue were frequent with both procedures and were compared in responses to questionnaires. A total of 85% of BM donors reported moderate or severe pain compared with 68% of BC donors (P=0.02). The median duration of pain was 14 days for BM donors compared with 3 days after BC mobilization (P<0.0001). More BM donors had pain for more than 7 days (75% vs 0%, P<0.0001). Severe fatigue was experienced by more BM donors (49 vs 16%, P<0.0001). Fatigue lasted significantly longer in BM donors (median 11 vs 4 days, P<0.0001) and more BM donors were fatigued for more than 1 week (69 vs 0%, P<0.0001). A total of 11 donors had both BM and BC collection; seven preferred the latter. Simply considered with respect to pain and fatigue, BC donation appears better tolerated by donors. However, there are other sequelae of both influencing the acceptability for individual donors.

LRIG1 and epidermal growth factor receptor in renal cell carcinoma: a quantitative RT--PCR and immunohistochemical analysis

In all, 31 renal cell carcinomas (RCCs) were examined for expression of the potential tumour suppressor LRIG1 (formerly Lig-1) and the epidermal growth factor receptor (EGFR). Eight matched samples of uninvolved kidney cortex were also evaluated. Gene expression was examined by quantitative real-time RT–PCR. In the eight matched sample pairs (uninvolved kidney cortex and tumour), protein expression was examined by immunohistochemistry. Conventional (clear cell) tumours showed an expected upregulation of EGFR. LRIG1 expression was generally downregulated in conventional and papillary RCC but not in chromophobic RCC. The ratio between EGFR and LRIG1 was more than 2.5-fold higher in the eight tumours compared with matched uninvolved kidney cortex and was at least two-fold higher than the mean normal ratio in 21 of 31 samples analysed. The observed downregulation of LRIG1 and increased EGFR/LRIG1 ratios are consistent with LRIG1 being a suppressor of oncogenesis in RCC by counteracting the tumour-promoting properties of EGFR. Further studies are justified to elucidate the explicit role of LRIG1 in the oncogenesis of RCC.

Quantification of Bax and Bcl2 in polymorphonuclear leukocytes from haemodialysis patients: relation to hydrogen peroxide

BACKGROUND

Bax and Bcl2 are two apoptosis-related molecules that play an important role in determining cell fate following oxidative injury. In the present study, we explored the relation of hydrogen peroxide (H2O2) generation by polymorphonuclear cells (PMNs) to the cytosolic expression of Bax and Bcl2 proteins and apoptosis in haemodialysis (HD) patients.

METHODS

Cytosolic generation of H2O2 by PMNs from control subjects and HD patients was measured by flow cytometry using the dichlorofluorescin diacetate assay. Bax and Bcl2 expression was detected by flow cytometry using FITC-conjugated antibodies. Apoptosis was quantified by flow cytometry using propidium iodide nuclear staining. To examine the effect of H2O2 on Bcl2 and Bax expression, PMNs from control subjects were briefly exposed to H2O2 (0.1-100 microM) for 10 min and then washed and cultured for 6 h, with or without catalase, a H2O2 detoxifying molecule. Bcl2 and Bax expression was determined by Western blot analysis.

RESULTS

Basal H2O2 generation by resting PMNs was significantly higher in HD patients compared with control subjects (211 +/- 115 vs. 23 +/- 5 MFI; P=0.002). However, PMNs from HD patients did not undergo accelerated programmed cell death compared with control subjects (58 +/- 7% vs. 46 +/- 5; P=0.14). Polymorphonuclear cells cytosolic Bcl2 was undetected in control subjects but detected in 25% of HD patients, and Bax was more frequently detected in PMNs from HD patients (75% vs. 67%; P=0.04). In the HD patients with detectable cytosolic Bax and Bcl2 proteins, the Bax to Bcl2 ratio inversely correlated with H2O2 levels (P<0.0001). Finally, brief exposure of PMNs to 0.1-100 microM of H2O2 resulted in a marked increase in Bcl2 expression (P=0.001), which was prevented by catalase (P=0.05). There was no apparent effect on Bax expression.

CONCLUSIONS

This study demonstrates that in HD patients, high-resting cytosolic H2O2 production by PMNs is not associated with accelerated in vitro apoptosis, and that the Bax/Bcl2 system may counter-balance the deleterious effects of reactive oxygen species in human PMNs.

Impact of iron dextran on polymorphonuclear cell function among hemodialysis patients

BACKGROUND

Polymorphonuclear cell (PMN) dysfunction and the increased use of parenteral iron may be important contributory factors to bacterial infections among patients with end-stage renal disease (ESRD) on maintenance hemodialysis (HD). We compared the in vitro impact of a commonly used parenteral iron preparation, iron dextran, on PMN function and viability between a group of HD patients with normal iron indices and healthy subjects.

METHODS

Eleven patients with ESRD on HD and 10 healthy subjects were studied. PMN harvested from heparinized blood were incubated with iron dextran (0 - 20 mM) in culture medium (RPMI) for 24 hours at 37 degrees C with 5% CO2 following which function and viability were assessed by flow cytometry using appropriate fluorescent labels.

RESULTS

Unstimulated, S. aureus and N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated hydrogen peroxide (H2O2) production was significantly higher in PMN unexposed to iron dextran from HD patients compared to those from healthy subjects. Iron dextran had no impact on unstimulated PMN H2O2 production in either group. In the healthy group, the only significant change occurred with 4-beta-phorbol 12-beta-myristate 13-alpha-acetate (PMA) stimulation, where cells exposed to 0.2 and 2.0 mM iron dextran produced less H2O2 relative to PMN unexposed to iron dextran (p < 0.05). In the HD group, all concentrations of iron dextran significantly attenuated H2O2 production stimulated by S. aureus, fMLP and PMA compared to PMN unexposed to iron dextran. Although PMN phagocytosis decreased with exposure to increasing concentration of iron dextran in both healthy subjects and HD patients, these changes did not achieve statistical significance. No significant changes in PMN viability or apoptosis were seen in either group after exposure to iron dextran.

CONCLUSIONS

These results indicate that iron dextran, a standard parenteral iron preparation, attenuates PMN function in HD patients with normal iron indices at clinically relevant concentrations. Further studies are required to evaluate and compare the impact of newer preparations of parenteral iron, such as iron sucrose and ferric gluconate, on PMN function.

The effects of cigarette smoke extract on the endothelial production of soluble intercellular adhesion molecule-1 are mediated through macrophages, possibly by inducing TNF-alpha release

Cigarette smoke (CS) is a major risk factor for many human diseases, although the underlying mechanisms are not clearly understood. This study was undertaken to investigate the effect of a water-soluble CS extract (CSE) on soluble intercellular adhesion molecule-1 (sICAM-1) production by human umbilical vein endothelial cells (HUVEC) mediated through ANA-1 macrophages. First, macrophages were incubated with or without CSE, and the supernatants collected at different time points were used to measure the levels of tumor necrosis factor-alpha (TNF-alpha) and sICAM-1 by enzyme-linked immunosorbent assay (ELISA); and second, HUVEC were cultured with CSE, a vehicle, or ANA-1 supernatants (collected at different time points) and the sICAM-1 levels in the supernatants were measured by ELISA at 24 h. The results showed that: i) CSE showed no effect on the production of sICAM-1 by HUVEC; ii) sICAM-1, in unstimulated or CSE-stimulated ANA-1 supernatants collected at different time points, was under the detectable level; iii) CSE-stimulated ANA-1 supernatants collected at 3 or 6 h showed no effect on sICAM-1 production in HUVEC, while those collected at 12 and 24 h significantly increased sICAM-1 production (p < 0.02 and p < 0.005, respectively); iv) no significant difference in TNF-alpha levels was detected between unstimulated and CSE-stimulated macrophage supernatants collected at 3 and 6 h, however, higher levels of TNF-alpha were found in CSE-stimulated supernatants collected at 12 and 24 h (p < 0.05 and p < 0.002, respectively); and v) a significant correlation (r = 0.9693, p < 0.001) was found between the levels of TNF-alpha in CSE-stimulated ANA-1 supernatants and those of related sICAM-1 production in HUVEC. These findings indicate that CSE indirectly increases the production of sICAM-1 in HUVEC by activating macrophages, which possibly induces the release of TNF-alpha from them, which in turn enhances the production of sICAM-1 from HUVEC.

Identification of cis-DNA regions controlling Bmp4 expression during tooth morphogenesis in vivo

Epithelial-mesenchymal interactions are required for tooth formation. Bone morphogenetic protein 4 (Bmp4) is a crucial signaling molecule during this process. For better understanding of the role of the Bmp4 gene during tooth development, we studied the mechanisms that control its temporal and spatial expression during development. Using a transgenic approach, we determined that the domains which controlled Bmp4 expression in epithelium-derived ameloblasts were located in the region between 0.26 kb and 1.1 kb of the murine Bmp4 promoter. In contrast, the domains controlling Bmp4 expression in mesenchyme-derived odontoblasts and pulp cells existed in other regions of the Bmp4 gene. We have also demonstrated that the domains controlling Bmp4 expression in primordial tooth cells differ from those controlling Bmp4 expression in mature tooth tissues. The determination of unique domains by controlling the expression of the Bmp4 gene suggests that different transcriptional factors regulate the Bmp4 level at different stages during tooth morphogenesis.

[Endovascular treatment for peripheral arterial stenosis with endoluminal stent]

OBJECTIVE

To initially evaluate the effect and security of endovascular treatment for arterial stenosis with endoluminal stent.

METHODS

Thirty-four cases of arterial stenosis were treated with endoluminal stent from March 1999 to May 2001. The stenosis involved descending aorta (1 case), iliac artery (2), femoral artery (2), carotid artery (1), subclavian artery (2) and renal artery (1). Thiry-three cases had arteriosclerosis and one Takayasu's arteritis. Twenty-six cases were percutaneously punctured and eight cases were punctured directly.

RESULTS

All the 34 cases had the stents successfully implanted. However, one case of descending aorta stenosis died on the operation day due to rupture of the descending aorta. Dissection was performed in thirteen cases after balloon dilation and hematoma was seen at the puncturing point in eleven cases. TIA (transient ischemia attack) and cerebral infarction did not occur in the case of carotid arterial stenosis. For those with stenosis in lower extremities, ABI (ankle-brachial index) increased from 0.45 to 0.72 postoperatively. The brachial pressure of two cases of subclavian arterial stenosis returned to normal postoperatively. The blood pressure of case of renal arterial stenosis reduced from 180/120 mm Hg to 140/90 mm Hg. All the cases were followed up for one month to 26 months. Thrombosis of the arteries treated occurred in two cases of iliac arterial stenosis four and six months postoperatively.

CONCLUSIONS

The effect of endovascular treatment for arterial stenosis with endoluminal stent is satisfactory. Endovascular therapy is especially suitable for iliac arterial and limited stenosis of the subclavian artery. However, it should be cautiously used in the stenosis of the carotid artery.

Improvement of in-rumen digestibility of alfalfa forage by genetic manipulation of lignin O-methyltransferases

Lignin inhibits forage digestibility by ruminant animals, and lignin levels and the proportion of dimethylated syringyl (S) lignin monomers increase with progressive maturity in stems of forage crops. We generated transgenic alfalfa (Medicago sativa L.) with reduced lignin content and altered lignin composition. Down-regulation of caffeic acid 3-O-methyltransferase (COMT) reduces lignin content, accompanied by near total loss of S lignin, whereas down-regulation of caffeoyl coenzyme A 3-O-methyltransferase (CCoAOMT) reduces lignin content without reduction in S lignin. These changes are not accompanied by altered ratios of cell wall polysaccharides. Analysis of rumen digestibility of alfalfa forage in fistulated steers revealed improved digestibility of forage from COMT down-regulated plants, but a greater improvement in digestibility following down-regulation of CCoAOMT. The results indicate that both lignin content and composition affect digestibility of alfalfa forage, and reveal a new strategy for forage quality improvement by genetic manipulation of CCoAOMT expression.

Expression of multidrug resistance protein and messenger RNA correlate with (99m)Tc-MIBI imaging in patients with lung cancer

In vitro studies have shown that (99m)Tc-sestamibi (MIBI) is a transport substrate for the P-glycoprotein (Pgp) pump and the multidrug resistance-associated protein (MRP) pump. However, whether MRP and lung resistance protein (LRP) affect tumor accumulation and efflux of (99m)Tc-MIBI in lung cancer is not known. In this study, we explored whether Pgp and the other pumps, MRP and LRP, affect tumor accumulation and efflux of (99m)Tc-MIBI in lung cancer.

METHODS

Thirty-four lung cancer patients who underwent surgery were examined. Before surgery, (99m)Tc-MIBI SPECT was performed 15 min and 180 min after injection, and early uptake, delayed uptake (L/Nd), and washout rate (L/Nwr) of (99m)Tc-MIBI were obtained. Pgp, MRP, and LRP expression were investigated by immunohistochemistry. The messenger RNA (mRNA) level of Pgp, MRP, and LRP was determined by real-time reverse-transcription polymerase chain reaction. The lung cancer (99m)Tc-MIBI images were correlated with protein and mRNA expression.

RESULTS

The mean L/Nd of the Pgp (-) group was significantly higher than that of the Pgp (++) group (P = 0.0324). The Pgp (++) group had a higher L/Nwr than did the Pgp (-) group (P = 0.0269). The mean L/Nd of the Pgp mRNA low-expression group was significantly higher than that of the Pgp mRNA high-expression group (P = 0.0127). The Pgp mRNA high-expression group had a higher L/Nwr than did the Pgp mRNA low-expression group (P = 0.0825). No appreciable correlation was found between the lung cancer (99m)Tc-MIBI images and the expression of MRP or LRP on the level of protein or mRNA.

CONCLUSION

These data suggest that an increased level of Pgp expression correlates with a low accumulation on delayed scans and a high L/Nwr of (99m)Tc-MIBI in lung cancer. Neither MRP nor LRP expression on the level of either protein or mRNA correlated significantly with tumor accumulation or efflux of (99m)Tc-MIBI in lung cancer.

Map self-validation: improved criteria to resolve the SIR or SAS phase ambiguity

A procedure was recently described that used the correlation coefficient (CC) agreement between the observed /F(h)/ and their associated unbiased 'omit map' extrapolated values /X(h)/ from an initial trial map as the basis for resolving the SIR or SAS phase ambiguity. It is noted here that a significant improvement in selectivity can be obtained if this agreement is expressed in terms of the complex-valued F(h) and X(h). A new scheme is outlined to exploit the weighted average of the two SIR or SAS phase choices. This procedure requires six FFTs per phase compared with three for the older method that randomly selected either of the two permitted phase choices from the Argand diagram as starting values. Trial calculations are encouraging for applications as low as 4 A resolution.

[Experimental comparison of the adipocytal injuries harvested by three surgical methods]

OBJECTIVE

To evaluate the degree of the injuries on the fat cells harvested by cutting, syringe aspiration and pipe suction techniques.

METHODS

Fat tissue was removed from lower abdomen by cutting, syringe aspiration and pipe suction. The excised adipose tissue was cut into 3 mm diameter fat particles, whereas the adipose tissue from syringe aspiration group was taken by the syringe suction technique with No. 22 needle and in the pipe suction group the adipose tissue from the suction tube with 8 mm in diameter. Each sample was fixed in 10% buffered formalin and stained with hematoxylin technique and wilder's silver technique. The fat cells were evaluated under microscope.

RESULTS

The percentage of the injured fat cells was (8.6 +/- 1.8)% in cutting technique, (15.7 +/- 2.4)% in syringe aspiration and (76.4 +/- 8.7)% in pipe suction respectively. They had significant differences between each other.

CONCLUSIONS

Among the three methods, the degree of the injuries on the fat cells was mostly serious in the way of pipe suction technique while minimal in the way by cutting.

[An initial study on DSA features of pulmonary hypoperfusion second to cancerous invasion of central pulmonary artery in lung cancer]

BACKGROUND

To study digital subtraction angiography ( DSA) features of pulmonary hypoperfusion in lung cancer with cancerous invasion of central pulmonary artery ( CICPA) .

METHODS

Twenty-six cases of lung cancer combined with CICPA underwent pulmonary DSA. The DSA features of pulmonary hypoperfusion, including pulmonary vessel signs and lung parenchyma signs, were observed, and the time-density curve( TDC) of both abnormal sides and the coordinate normal sides was drawn and analyzed.

RESULTS

There were 38 lobar arteries showing cancerous invasion in 26 cases and 34 ( 89. 5%) lobes presenting pulmonary hypoperfusion. There was a good correlation between pulmonary hypoperfusion and the degree of central pulmonary artery ( CPA) stenosis ( P < 0. 05) . DSA pulmonary vessel signs included abrupt cut-off ( 11. 8%, 4/ 34) or less branches ( 88. 2%, 30/ 34) of pulmonary arteries, and disappearance ( 41. 2%, 14/ 34) or decrease ( 58. 8%, 20/ 34) of terminal pulmonary arteries. DSA lung parenchyma signs were pulmonary capillary perfusion disappearing ( 14. 7%, 5/ 34) or weakening ( 85. 3%, 29/ 34) .

CONCLUSIONS

Pulmonary lobes supplied by central pulmonary arteries invaded by lung cancers usually present pulmonary hypoperfusion. Pulmonary hypoperfusion is closely correlative with the degree of CPA stenosis. Pulmonary vessel signs and lung parenchyma signs are very important phenomena of pulmonary hypoperfusion.

The biosynthesis of monolignols: a "metabolic grid", or independent pathways to guaiacyl and syringyl units?

Lignin is a complex polymer formed by the oxidative polymerization of hydroxycinnamyl alcohol derivatives termed monolignols. The major monolignols in dicotyledonous angiosperm lignin are monomethylated guaiacyl (G) units derived from coniferyl alcohol, and dimethylated syringyl (S) units derived from sinapyl alcohol. The biochemical pathways leading to the formation of monolignols feature successive hydroxylation and O-methylation of the aromatic ring and conversion of the side chain carboxyl to an alcohol function. The current view of the monolignol biosynthetic pathway envisages a metabolic grid leading to G and S units, through which the successive hydroxylation and O-methylation reactions may occur at different levels of side chain oxidation. The present article assesses biochemical and genetic evidence for and against such a model, including recent data on the methylation reactions of monolignol biosynthesis in alfalfa. We draw attention to portions of the currently accepted monolignol pathway that may require revision, and suggest an alternative model in which metabolic channeling allows for independent pathways to G and S lignin.

Fargosides A-E, triterpenoid saponins from Holboellia fargesii

Five new triterpenoid saponins, fargosides A, B, C, D, and E, were isolated from the roots of Holboellia fargesii. The structures of fargosides A-E were elucidated on the basis of chemical and physicochemical evidence and found to be 3beta,20alpha-dihydroxy-29-norolean-12-en-28-oic acid 3-O-beta-D-xylopyranosyl-(1-->2)-beta-D-glucopyranoside (1), 3beta,20alpha,24-trihydroxy-29-norolean-12-en-28-oic acid 23-O-beta-D-fucopyranosyl-(1-->2)-[alpha-L-arabinopyranosyl-(1-->3)]-beta-D-glucopyranoside (2), 3beta,23-dihydroxy-30-norolean-2,20(29)-dien-28-oic acid 3-O-alpha-L-arabinopyranosyl-(1-->2)-[beta-D-glucopyranosyluronic acid-(1-->3)]-alpha-L-arabinopyranoside (3), 3beta,23-dihydroxy-30-norolean-12,20(29)-dien-28-oic acid 3-O-methyl beta-D-glucopyranosyluronate-(1-->3)-alpha-L-arabinopyranoside (4), and 3beta,23-dihydroxy-olean-12-en-28-oic acid 3-O-methyl beta-D-glucopyranosyluronate-(1-->3)-alpha-L-arabinopyranoside (5), respectively.

Accessibility of DNA polymerases to repair synthesis during nucleotide excision repair in yeast cell-free extracts

Nucleotide excision repair (NER) removes a variety of DNA lesions. Using a yeast cell-free repair system, we have analyzed the repair synthesis step of NER. NER was proficient in yeast mutant cell-free extracts lacking DNA polymerases (Pol) beta, zeta or eta. Base excision repair was also proficient without Polbeta. Repair synthesis of NER was not affected by thermal inactivation of the temperature-sensitive mutant Polalpha (pol1-17), but was reduced after thermal inactivation of the temperature-sensitive mutant Poldelta (pol3-1) or Polvarepsilon (pol2-18). Residual repair synthesis was observed in pol3-1 and pol2-18 mutant extracts, suggesting a repair deficiency rather than a complete repair defect. Deficient NER in pol3-1 and pol2-18 mutant extracts was specifically complemented by purified yeast Poldelta and Polvarepsilon, respectively. Deleting the polymerase catalytic domain of Polvarepsilon (pol2-16) also led to a deficient repair synthesis during NER, which was complemented by purified yeast Polvarepsilon, but not by purified yeast Poleta. These results suggest that efficient repair synthesis of yeast NER requires both Poldelta and Polvarepsilon in vitro, and that the low fidelity Poleta is not accessible to repair synthesis during NER.

Familial thoracic aortic aneurysms and dissections: genetic heterogeneity with a major locus mapping to 5q13-14

BACKGROUND

Aneurysms and dissections affecting the ascending aorta are associated primarily with degeneration of the aortic media, called medial necrosis. Families identified with dominant inheritance of thoracic aortic aneurysms and dissections (TAA/dissections) indicate that single gene mutations can cause medial necrosis in the absence of an associated syndrome.

METHODS AND RESULTS

Fifteen families were identified with multiple members with TAAs/dissections. DNA from affected members from 2 of the families was used for a genome-wide search for the location of the defective gene by use of random polymorphic markers. The data were analyzed by the affected-pedigree-member method of linkage analysis. This analysis revealed 3 chromosomal loci with multiple markers demonstrating evidence of linkage to the phenotype. Linkage analysis using further markers in these regions and DNA from 15 families confirmed linkage of some of the families to 5q13-14. Genetic heterogeneity for the condition was confirmed by a heterogeneity test. Data from 9 families with the highest conditional probability of being linked to 5q were used to calculate the pairwise and multipoint logarithm of the odds (LOD) scores, with a maximum LOD of 4.74, with no recombination being obtained for the marker D5S2029. In 6 families, the phenotype was not linked to the 5q locus.

CONCLUSIONS

A major locus for familial TAAs and dissections maps to 5q13-14, with the majority (9 of 15) of the families identified demonstrating evidence of linkage to this locus. The condition is genetically heterogeneous, with 6 families not demonstrating evidence of linkage to any loci previously associated with aneurysm formation.

Translesion synthesis by yeast DNA polymerase zeta from templates containing lesions of ultraviolet radiation and acetylaminofluorene

In the yeast Saccharomyces cerevisiae, DNA polymerase zeta (Polzeta) is required in a major lesion bypass pathway. To help understand the role of Polzeta in lesion bypass, we have performed in vitro biochemical analyses of this polymerase in response to several DNA lesions. Purified yeast Polzeta performed limited translesion synthesis opposite a template TT (6-4) photoproduct, incorporating A or T with similar efficiencies (and less frequently G) opposite the 3' T, and predominantly A opposite the 5' T. Purified yeast Polzeta predominantly incorporated a G opposite an acetylaminofluorene (AAF)-adducted guanine. The lesion, however, significantly inhibited subsequent extension. Furthermore, yeast Polzeta catalyzed extension DNA synthesis from primers annealed opposite the AAF-guanine and the 3' T of the TT (6-4) photoproduct with varying efficiencies. Extension synthesis was more efficient when A or C was opposite the AAF-guanine, and when G was opposite the 3' T of the TT (6-4) photoproduct. In contrast, the 3' T of a cis-syn TT dimer completely blocked purified yeast Polzeta, whereas the 5' T was readily bypassed. These results support the following dual-function model of Polzeta. First, Polzeta catalyzes nucleotide incorporation opposite AAF-guanine and TT (6-4) photoproduct with a limited efficiency. Secondly, more efficient bypass of these lesions may require nucleotide incorporation by other DNA polymerases followed by extension DNA synthesis by Polzeta.

[CT appearance and its diagnosis value in liver cancer after transcatheter oily chemoembolization combining with high intensity focused ultrasound therapy]

OBJECTIVE

To study the CT appearances of liver cancer after transcatheter oily chemoembolization (TOCE) combining with high intensity focused ultrasound (HIFU) therapy.

METHODS

Fifty cases of clinically-proved liver cancer were included into this study. For each case, CT scanning before and after TOCE, HIFU treatment was performed. The volumes of the masses were measured. The appearances of the oily deposition and the density, shape, border of the lesions were observed.

RESULTS

The lesions became smaller in 38 cases (38/50, 76%) after the treatment. The differences were detected statistically in the ratio of the tumor shrinkage between the single TOCE therapy and the combined treatment (P<0.05). The ratio of the tumor shrinkage was closely correlative with the quantity of the oily deposition, but not with the diameter of the tumor before treatment. The lowered densities were showed in 30 cases (30/50, 60%) and the borders became regular and clear in 16 cases after HIFU therapy.

CONCLUSIONS

TOCE combining with HIFU therapy in the patients with liver cancer can make the tumor smaller. CT is of great value in the evaluation of efficacy and prognosis.

Cloning, characterization, and expression of human LIG1

Growth factor receptors are frequently amplified and over-expressed in various human cancers. Recently, a Drosophila cell surface protein, Kekkon-1, was found to participate in an epidermal growth factor (EGF) driven negative feedback loop. Kekkon-1 is induced by EGF, binds to the EGF-receptor, and inhibits receptor-mediated signaling. Here, we have searched for human genes with homologies to Kekkon-1 and identified human LIG1. The gene is the human homologue of mouse Lig-1 and is located on chromosome band 3p14, a region frequently deleted in various human cancers. It is predicted to encode a transmembrane cell-surface protein with extracellular leucine-rich repeats and immunoglobulin-like domains. LIG1 mRNA was detected in all tissues analyzed. The highest and lowest relative expression levels were found in brain and spleen, respectively, and differed by more than 200-fold. Taken together, our data are compatible with a role for LIG1 as a growth and tumor suppressor in human tissues.

The use of the Australian Basic Treatment Equivalent (BTE) workload measure for linear accelerators in Canada

The Inter Society of Radiation Oncologists of North America (ISRON) workload standard for linear accelerators is the one most widely used; it regards the treatment of 250 or more patients per year as an acceptable limit. Nevertheless, there is concern that this standard does not represent the current workload of linear accelerators, given that the complexity of techniques and equipment has increased significantly since the ISRON model was developed in the late 1980s. Delaney et al. recently validated a workload indicator for Australian (AUS) centres, known as the basic treatment equivalent (BTE). They showed that this was a better predictor of workload and that there was less variation between centres using this model than there would have been by using fields/hour. This centre attempted to validate this model for use in a Canadian centre, by collecting treatment data on all linear accelerator-treated patients during February 1998. The linear accelerators at this centre delivered 2,295 fractions (6,928 fields) in 662 hours during February 1998. When 15 minutes was used as a denominator, the BTE model functioned as a better workload indicator than simple measures such as fields/hour. It also had better performance in reducing variability between machines. A BTE of 3,403 was calculated for these machines. The mean value for fields/hour, BTE/hour and BTE/fraction for this centre fell within the range of values quoted by AUS centres. The BTE/fraction value for this centre was relatively high compared with the AUS mean, indicating this centre's reliance on the use of a high number of complex techniques. We recommend that the model should be further refined for the Canadian context by developing BTE values with the use of local time and motion studies, including factors such as multileaf collimators and enhanced dynamic wedges.