Technical advance: a high throughput system for transposon tagging and promoter trapping in tomato

We describe new tools for functional analysis of the tomato genome based on insertional mutagenesis with the maize Ac/Ds transposable elements in the background of the miniature cultivar Micro-Tom. 2932 F3 families, in which Ds elements transposed and were stabilized, were screened for phenotypic mutations. Out of 10 families that had a clear mutant phenotype, only one mutant was Ds-tagged. In addition, we developed promoter trapping using the firefly luciferase reporter gene and enhancer trapping, using beta-glucuronidase (GUS). We show that luciferase can be used as a non-invasive reporter to identify, isolate and regenerate somatic sectors, to study the time course of mutant expression, and to identify inducible genes. Out of 108 families screened for luciferase activity 55% showed expression in the flower, 11% in the fruit and 4% in seedlings, suggesting a high rate of Ds insertion into genes. Preferential insertion into genes was supported by the analysis of Ds flanking sequences: 28 out of 50 sequenced Ds insertion sites were similar to known genes or to ESTs. In summary, the 2932 lines described here contain 2-3 Ds inserts per line, representing a collection of approximately 7500 Ds insertions. This collection has potential for use in high-throughput functional analysis of genes and promoter isolation in tomato.

The effects of cyclic loading on pull-out strength of sacral screw fixation: an in vitro biomechanical study

STUDY DESIGN

The pull-out strength of sacral screw fixation after cyclic loading was tested using young human cadaveric specimens.

OBJECTIVES

To evaluate the effects of fatigue loading on the pull-out strength of medial and lateral unicortical and bicortical sacral screws and to correlate the pull-out strength with sacral bone density and the screw insertion torque.

SUMMARY OF BACKGROUND DATA

The immediate biomechanical effects of depth of penetration, screw orientation, and bone density on sacral screw fixation have been studied in aged cadaveric specimens. The effect of cyclic loading on the pull-out strength of sacral screw fixation is unknown, however, and data from young specimens is rare.

METHODS

Eleven fresh specimens of human sacrum were used in this study. Bone mineral density at the vertebral body and the ala were determined by peripheral quantitative computed tomography. Seven-millimeter compact Cotrel-Dubousset sacral screws were inserted into the sacrum anteromedially and anterolaterally, both unicortically and bicortically, and the insertion torque for each screw was measured. Cyclic loading from 40 to 400 N was applied to each screw at a frequency of 2 Hz up to 20,000 cycles. Pull-out tests were conducted after completion of the fatigue tests.

RESULTS

The average bone density was 0.38 +/- 0.08 g/mL at the S1 body and 0.24 +/- 0.05 g/mL at the S1 ala. The insertion torque and average pull-out force after cyclic loading were significantly higher for bicortical fixation than for unicortical fixation for a particular screw alignment. The pull-out strength and insertion torque of medially oriented fixation was always higher than that for lateral fixation, however, regardless of whether the insertion was unicortical or bicortical. The pull-out force of unicortical and bicortical medial screw fixations after cyclic loading showed significant linear correlations with both the insertion torque and the bone mineral density of the S1 body.

CONCLUSIONS

In a young population, screw orientation (anterolateral or anteromedial) was more important in determining pull-out strength than screw depth (unicortical or bicortical) after fatigue loading, anteromedially directed screws being significantly stronger than laterallyplaced screws. Bone mineral density of the S1 body andinsertion torque were good preoperative and intraoperative indicators of screw pull-out strength.

An SP1-like cis-element is the major DNA motif for differential expression regulation of the adipocyte amino acid transporter

Adipocyte amino acid transporter (AAAT) is induced during the 3T3-L1 preadipocyte differentiation process. In the -1819-bp 5'-upstream flanking region of the AAAT genomic gene, six DNase I protected sites were identified by using the 3T3-L1 adipocyte nuclear extract. Results of chloramphenicol acetyltransferase (CAT) expression from the chimeric AAAT promoter-driven CAT reporter gene indicated that one protein binding site, from -68 to -26, was essential for the promoter activity. However, this protein binding site does not contain recognition sites of the transcription factors important for adipocyte differentiation, i.e., the C/EBP or PPAR family. Further analysis revealed that the DNA sequence, TTCAAGTCCCGCCCTCCGCT from -65 to -46, was the cis-element essential and partially sufficient for inducible activity of the AAAT gene promoter.

Differential expression of the adipocyte amino acid transporter is transactivated by SP1 and SP3 during the 3T3-L1 preadipocyte differentiation process

It was identified that a Sp1-like cis-element in the adipocyte amino acid transporter gene (AAAT) promoter is the major cis-motif for its induced expression during the 3T3-L1 preadipocyte differentiation process. Electrophoretic mobility shift analysis of this cis DNA element showed that the transcription factors binding to this sequence were Sp1 and Sp3. Protein analysis of Sp1 and Sp3 in nuclear extracts from 3T3-L1 cells at various differentiation stages indicated that these two transcription factors existed in noninduced 3T3-L1 preadipocytes, but they did not bind to the AAAT promoter element with high affinity. They were activated after differentiation induction. It was further demonstrated that dephosphorylation of Sp1 increased its binding affinity to this inducible AAAT promoter element.

Enhanced sensitivity to anti-benzo(a)pyrene-diol-epoxide DNA damage correlates with decreased global genomic repair attributable to abrogated p53 function in human cells

DNA damage from exposure to environmental chemical carcinogens and failure of repair systems to eliminate these lesions from the genome are considered as the crucial initial steps in the development of various human malignancies. Many cellular proteins are known to play vital roles to overcome the effects of DNA damage. Among such proteins, p53 is known to respond to DNA damage by accumulating in the nucleus and inhibiting cell cycle progression to facilitate DNA repair and the maintenance of genomic stability. In this study, we have investigated the role of p53 protein in modulating nucleotide excision repair of anti-benzo-(a)pyrene-diol-epoxide (BPDE)-DNA adducts and related effects using human fibroblasts with normal (p53-WT) and altered p53 protein (p53Mut and p53-Null). Interestingly, irrespective of the presence or absence of p53, the anti-BPDE dose-dependent p21 protein induction response was qualitatively comparable in all of the three cell lines. However, cells with defective p53 function were deficient for the removal of anti-BPDE-DNA adducts from the overall genome compared to cells with wild-type p53 activity. Strand-specific repair analysis within the individual strands of the p53 gene revealed decreased repair of adducts from the nontranscribed strand in p53-Mut and p53-Null cells. However, the repair of the transcribed strand appeared to be identical in all of the three cell lines. Furthermore, p53-Mut and p53-Null cells were more sensitive than p53-WT cells and displayed increased levels of anti-BPDE-induced apoptosis. Thus, wild-type p53 is required for the efficient global genomic repair of anti-BPDE-induced DNA adducts from the overall genome, but not for transcription-coupled repair of actively transcribed genes. These findings indicate that inefficient DNA repair of potentially cytotoxic and mutagenic lesions from the nontranscribed strand due to the loss of p53, but not the loss of p21, function might be responsible for enhanced cytotoxicity and apoptosis in human cells upon DNA damage.

Decreased DNA repair efficiency by loss or disruption of p53 function preferentially affects removal of cyclobutane pyrimidine dimers from non-transcribed strand and slow repair sites in transcribed strand

The tumor suppressor protein p53 plays a central role in modulating the cellular responses to DNA damage. Several recent studies, undertaken with the whole genomic DNA or full-length gene segments, have shown that p53 is involved in nucleotide excision repair and it selectively influences the adduct removal from the non-transcribed strand in the genome. In this study, we have analyzed the damage induction at nucleotide resolution by ligase-mediated polymerase chain reaction and compared the repair of ultraviolet radiation-induced cyclobutane pyrimidine dimers within exon 8 of p53 gene in normal and Li-Fraumeni syndrome fibroblasts as well as in normal and human papillomavirus 16 E6 and E7 protein-expressing human mammary epithelial cells. The results demonstrate that (i) loss or disruption of p53 function decreases efficiency of DNA repair, by preferentially affecting the repair of non-transcribed strand and of intrinsically slow repair sites in transcribed strand; (ii) mutant p53 protein affects DNA repair, at least of non-transcribed strand, in a dominant negative manner; and (iii) pRb does not have an effect on the repair of DNA damage within transcribed or non-transcribed strand. The overall data suggest that p53 could regulate excision repair or related events through direct protein-protein interaction.

[Normal anatomy and related pathological changes of shoulder on MRI]

OBJECTIVE

To describe the normal anatomy and common abnormal changes of rotator cuff impingement and tears and recurrent anterior instability of shoulder joint in MRI pictures.

METHODS

MRI was compared in 285 patients with shoulder diseases and 20 patients with symptomatic shoulder diseases.

RESULTS

On oblique coronal image, the supraspinatus presented moderate signal intensity and low signal intensity in its tendon-muscle conjunction ranging from the humeral head to the greater tuberosity. The MRI manifestations of impingement lesion of the rotator cuff were as follows: high signal intensity of tendons, changes of their shapes, retraction of tendon-muscle conjunction, and muscle atrophy with high signal intensity. On T1-weighted axial image, the anterior and posterior glenohumeral labrum, the long head biceps tendon were displayed in low signal intensity. The anterior labrum manifested a sharp triangle contour and the posterior labrum a round one. The whole four muscles of the rotator cuff manifested on oblique sagital image. However, it was of less value in detecting the abnormalities of the rotator cuff and the glenohumeral labrum on sagittal imaging. The sensitivity in demonstrating rotator cuff complete tear was 95% for MRI and 91% for arthrography; the specificity was 88% for MRI and 100% for arthrography. The sensitivity and specificity of MRI were 96% and 75% for detecting glenoid labrum abnormalities, and 78% and 88% for detecting labrum tear in anterior recurrent dislocation of the shoulder.

CONCLUSIONS

Magnetic resonance imaging with its excellent contrast resolution in multiple anatomic planes allows noninvasive visualization of bone and soft tissues in the rotator cuff and labrum.

Atherosclerosis risk factors: the possible role of homocysteine

Atherosclerosis is the leading cause of death in North America. It is characterized by thickening of the coronary artery wall by the formation of plaques, resulting in reduced blood flow. Plaque rupture and the consequent thrombosis may lead to sudden blockage of arteries and causing stroke and heart attack. In the last several decades, more than 250 factors associated with the development of coronary artery disease have been identified. Recently, a relationship between atherosclerosis and elevated homocysteine level in the blood has been established. The mechanism for the production of atherosclerosis by homocysteine has been investigated. When human hepatoma cells (HepG2) were incubated with 4 mM homocysteine, enhancements in the production of cholesterol and secretion of apolipoprotein B-100 were observed. The stimulatory effect on cholesterol synthesis was mediated via the enhancement of HMG-CoA reductase, which catalyzes the rate-limiting step in cholesterol biosynthesis. Cholesterol appears to play an important role in the regulation of apoB-100 secretion by hepatocytes. It is plausible that the increase in apoB secretion was caused by the elevated cholesterol level induced by homocysteine. The ability of homocysteine to produce a higher amount of cholesterol and promote the secretion of apoB would provide a plausible mechanism for the observed relationship between hyperhomocysteinemia and the development of atherogenesis and coronary artery disease.

The orphan nuclear receptor Ear-2 is a negative coregulator for thyroid hormone nuclear receptor function

Thyroid hormone (T3) nuclear receptors (TR) are ligand-dependent transcription factors which regulate growth, differentiation, and development. One emerging hypothesis suggests that TR mediate these diverse effects via a large network of coregulators. Recently, we found that TR-mediated transcriptional responses varied in six cell lines derived from different tissues. We therefore used human TR subtype beta1 (TRbeta1) as bait to search for coregulators in human colon carcinoma RKO cells with a yeast two-hybrid system. RKO cells exhibited T3-dependent and -independent transcriptional activation. One of the three positive clones was identified as Ear-2, which is a distant member of the chick ovalbumin upstream promoter-transcription factors of the orphan nuclear receptor family. The physical interaction between Ear-2 and TRbeta1 was further confirmed by specific binding of Ear-2 to glutathione S-transferase-TRbeta1. In addition, Ear-2 was found to associate with TRbeta1 in cells. As a result of this physical interaction, binding of TRbeta1 to the T3 response elements was inhibited. Using reporter systems, we found that both the basal activation and the T3-dependent activation mediated by TRbeta1 were repressed by Ear-2 in CV1 cells. In RKO cells, however, the T3-independent transcriptional activity was more sensitive to the repression effect of Ear-2 than the T3-dependent transcriptional activity. The repression effect of Ear-2 was reversed by steroid hormone receptor coactivator 1. These results suggest that TR-mediated responses reflect a balance of corepressors and coactivators in cells. These findings further strengthen the hypothesis that the diverse activities of TR are achieved via a large network of coregulators that includes Ear-2.

Optical imaging as an adjunct to sonograph in differentiating benign from malignant breast lesions

The role of near infrared (NIR) diffusive light imaging as an adjunct to ultrasound in differentiating benign from malignant lesions was evaluated in 27 mammography patients with infiltrating ductal carcinomas, apocrine metaplasia, fibroadenomas, radial scar and ductal hyperplasia, cysts, and normal tissues. Conventional ultrasound/mammography images were graded based on BI-RADS assessment categories. The spatial NIR measurements were made at wavelengths of 750 and 830 nm. Functional images, such as relative changes of deoxyhemoglobin (deoxyHb) and total blood concentration, were estimated from the dual wavelength measurements. Maximum relative deoxyHb and blood concentration changes were measured, and spatial correlation of masses in relative deoxyHb and blood concentration images for each breast were calculated. For the five biopsy proven benign lesions, ultrasound/mammography diagnoses were suspicious for malignancy (four cases) and highly suspicious for malignancy (one case). Four lesions showed less than 1.0 V maximum deoxyHb and less than 1.5 V maximum blood concentration levels on average and spatial image correlation showed no correlated masses in both deoxyHb and blood concentration images. For the four biopsy proven malignant lesions, ultrasound/mammography diagnoses were highly suspicious for malignancy. Maximum deoxyHb and blood concentration changes were greater than 2.9 V on average except one lesion which showed smaller deoxyHb signal (maximum 0.85 V) but the deoxyHb mass and blood concentration mass were highly correlated.

Effects of atorvastatin treatment on the oxidatively modified low density lipoprotein in hyperlipidemic patients

Atorvastatin is an established HMG-CoA reductase inhibitor which effectively reduces the plasma low density lipoprotein (LDL)-cholesterol level in hyperlipidemic patients. The present study was designed to investigate whether atorvastatin treatment can modify the biochemical content of oxidized LDL in hyperlipidemic patients and the ability of oxidized LDL to impair the endothelium-dependent relaxation of blood vessels. With atorvastatin (10 mg/day) treatment for 4 weeks in 19 type IIa hyperlipidemic patients, total cholesterol level was lowered by 23%, LDL-cholesterol was lowered by 32% and triacylglycerol was lowered by 19% as compared with dietary therapy alone. High density lipoprotein levels increased by approximately 9%. The ability of oxidized LDL from hyperlipidemic patients after atorvastatin treatment to impair the endothelium-dependent relaxation was significantly reduced as compared with dietary intervention alone. Analysis of the biochemical contents of oxidized LDL from this group revealed that there was an 11% reduction in lysophosphatidylcholine (LPC) as compared with the group that received only dietary counseling. A decrease in the C16:0 moiety with a corresponding increase in the C18:0 moiety of LPC in the oxidized LDL was also observed in the atorvastatin treated group. We propose that the observed reduction and the change in composition of acyl groups in LPC in the oxidized LDL of the atorvastatin-treated group results from a combination of the continued dietary treatment as well as drug therapy. In view of an observation that both C16:0 and C18:0 LPC species are equally potent in the impairment of endothelium-dependent relaxation of the aortic rings, we feel that the reduced level of LPC in the oxidized LDL produced by atorvastatin treatment is partially responsible for the improvement in endothelium control of vascular tone.

p53-degradation by HPV-16 E6 preferentially affects the removal of cyclobutane pyrimidine dimers from non-transcribed strand and sensitizes mammary epithelial cells to UV-irradiation

Nucleotide excision repair (NER), the most versatile and ubiquitous mechanism for DNA repair, operates to remove many types of DNA base lesions. We have studied the role of p53 function in modulating the repair of DNA damage following UV irradiation in normal and p53-compromised human mammary epithelial cells (HMEC). The effect of UV-induced DNA damage on cellular cytotoxicity and apoptosis was determined in conjunction with global, gene- and strand-specific repair. Cytotoxicity studies, using clonogenic survival and MTT assays, showed that HPV-16 E6-expressing HMEC were more UV sensitive than p53-WT cell lines. High apoptotic index obtained with p53-compromised cells was in conformity to both the low clonogenic survival and the low cellular viability. No discernible differences in the formation of initial UV-induced cyclobutane pyrimidine dimers (CPD) were observed in the cell lines of varying p53 functional status. However, the extent and the rate of damage removal from genome overall were highest for p53-WT cells. Further examination of strand-specific repair in the p53 gene revealed that the removal of CPD in the non-transcribed strand (NTS) was slower in p53-compromised cells compared to the normal p53-WT cell lines. These results suggest that loss of p53 function, in the absence of other genetic alterations, decreased both overall amount of CPD repaired and their removal rate from the genome. Additionally, normal function of p53 is required for the repair of the NTS, but not of the transcribed strand (TS) in genomic DNA in human epithelial cells. Thus, failure of quantitative removal of CPD by global genomic repair (GGR), due to loss of p53 function, causes the enhanced UV sensitivity and increased damage-induced apoptosis via a p53-independent pathway. Nevertheless, recovery of cells from UV damage requires normal p53 function and efficient GGR.

[Isolation of a gene related to trichosanthin-induced apoptosis (GRETA)]

Disturbance of the apoptosis-related signaling pathway is regarded as one of the critical factors for tumorigenesis. Isolation of the genes involved in the process of apoptosis would be thereby helpful to explore the mechanism of tumor transformation and to develop novel therapeutic approaches. Here we report a gene fragment GRETA, the gene related to trichosanthin-induced apoptosis, isolated from a leukemia cell line U937 undergoing apoptosis induced by a plant protein Trichosanhin (TCS). A 293bp segment of GRETA was revealed to be 78.3% homologous to Bruton's tyrosine kinase at nucleic acid level. And Northern blot analysis showed that three messengers of RNA with the size of about 0.8-kb, 2.0-kb and 7.0-kb, respectively, were detected in TCS-untreated U937 cells when probed with GRETA, but there were only 0.8-kb and 2.0-kb transcripts appeared in apoptotic U937 cells. In addition, the abundance of each transcript changed apparently. The 0.8-kb transcript, for example, was the main band in Northern analysis in apoptotic U937 cells while was only detected marginally in TCS-untreated cells. These data suggested a possible relationship between the alternative splicing patterns of GRETA and the apoptosis.

Arsenic trioxide-induced apoptosis and differentiation are associated respectively with mitochondrial transmembrane potential collapse and retinoic acid signaling pathways in acute promyelocytic leukemia

Recent studies showed that arsenic trioxide (As2O3) could induce apoptosis and partial differentiation of leukemic promyelocytes. Here, we addressed the possible mechanisms underlying these two different effects. 1.0 microM As2O3-induced apoptosis was associated with condensation of the mitochondrial matrix, disruption of mitochondrial transmembrane potentials (DeltaPsim) and activation of caspase-3 in acute promyelocytic leukemia (APL) cells regardless of their sensitivity to all-trans retinoic acid (ATRA). All these effects were inhibited by dithiothreitol (DTT) and enhanced by buthionine sulfoximine (BSO). Furthermore, BSO could also render HL60 and U937 cells, which had the higher cellular catalase activity, sensitive to As2O3-induced apoptosis. Surprisingly, 1.0 microM As2O3 did not induce the DeltaPsim collapse and apoptosis, while 0.1 microM As2O3 induced partial differentiation of fresh BM cells from a de novo APL patient. In this study, we also showed that 0.2 mM DTT did not block low-dose As2O3-induced NB4 cell differentiation, and 0. 10.5 microM As2O3 did not induce differentiation of ATRA-resistant NB4-derived sublines, which were confirmed by cytomorphology, expression of CD11b, CD33 and CD14 as well as NBT reduction. Another interesting finding was that 0.10.5 microM As2O3 could also induce differentiation-related changes in ATRA-sensitive HL60 cells. However, the differentiation-inducing effect could not be seen in ATRA-resistant HL60 sublines with RARalpha mutation. Moreover, low-dose As2O3 and ATRA yielded similar gene expression profiles in APL cells. These results encouraged us to hypothesize that As2O3 induces APL cell differentiation through direct or indirect activation of retinoic acid receptor-related signaling pathway(s), while DeltaPsim collapse is the common mechanism of As2O3-induced apoptosis.

Variation in bone mineral density of the sacrum in young adults and its significance for sacral fixation

STUDY DESIGN

Bone mineral density variations throughout the sacrum were measured and correlated with sacral screw insertion torque.

OBJECTIVE

To quantify bone mineral density variations within the S1 body and ala of young human specimens, especially along the pathways of sacral screws, and to examine the relation between sacral screw fixation and bone mineral density.

SUMMARY OF BACKGROUND DATA

Vertebral bone quality is an essential factor in anterior or posterior screw fixation of the spine. Several studies have been conducted regarding bone mineral density variations in the cervical and thoracolumbar spine. However, such variations in bone mineral density in the sacrum have not been well documented.

METHODS

The bone mineral density of 13 sacral specimens from young male cadavers (mean age, 31 years) was measured using highly accurate quantitative computed tomography. Variations in bone mineral density were measured in five transverse layers and seven vertical columns within the S1 body, and in four transverse layers and six vertical columns within the ala. The sacral screw insertion torque was measured (unicortical and bicortical), and the correlation with bone mineral density was calculated.

RESULTS

The mean bone mineral density of the S1 body was 381.9 +/- 59 mg/cm3, which was 31.9% higher than that of the sacral ala (mean, 296.9 +/- 86 mg/cm3) (P < 0.05). Bone mineral density of the superior sacral endplate was higher than that of any other transverse layer. Columns near the lateral posterior and lateral anterior of the S1 body had the highest bone mineral density. In the ala, bone mineral density values of the internal columns (pedicle) were the highest. Screw insertion torque for bicortical purchase along the S1 pedicle correlated well with the bone mineral density of the S1 body (r = 0.67, P < 0.05).

CONCLUSION

This study quantified the volumetric bone mineral density variations within the S1 body and ala, and a significant linear correlation between the screw insertion torque and bone mineral density was found. Optimal sacral screw insertion pathways were also outlined based on bone mineral density values.

The sigma(70) transcription factor TyrR has zinc-stimulated phosphatase activity that is inhibited by ATP and tyrosine

The TyrR protein of Escherichia coli (513 amino acid residues) is the chief transcriptional regulator of a group of genes that are essential for aromatic amino acid biosynthesis and transport. The TyrR protein can function either as a repressor or as an activator. The central region of the TyrR protein (residues 207 to 425) is similar to corresponding polypeptide segments of the NtrC protein superfamily. Like the NtrC protein, TyrR has intrinsic ATPase activity. Here, we report that TyrR possesses phosphatase activity. This activity is subject to inhibition by L-tyrosine and its analogues and by ATP and ATP analogues. Zinc ion (2 mM) stimulated the phosphatase activity of the TyrR protein by a factor of 57. The phosphatase-active site of TyrR was localized to a 31-kDa domain (residues 191 to 467) of the protein. However, mutational alteration of distant amino acid residues at both the N terminus and the C terminus of TyrR altered the phosphatase activity. Haemophilus influenzae TyrR (318 amino acid residues), a protein with a high degree of sequence similarity to the C terminus of the E. coli TyrR protein, exhibited a phosphatase activity similar to that of E. coli TyrR.

Cloning of cDNA and the gene encoding human hepatocyte nuclear factor (HNF)-3 beta and mutation screening in Japanese subjects with maturity-onset diabetes of the young

AIMS/HYPOTHESIS

Molecular defects of the genes for transcription factors, hepatocyte nuclear factor (HNF)-4 alpha, HNF-1 alpha, HNF-1 beta and insulin promoter factor-1 cause maturity-onset diabetes of the young (MODY1, 3, 5, and 4, respectively). This suggests the HNF-related transcription cascade is important in insulin secretion which is induced by glucose. These genes and the gene encoding glycolytic enzyme glucokinase (MODY2) are, however, responsible for only 15-20% of cases of MODY in the Japanese. Searching for a novel form of MODY in this population, we cloned a new candidate gene encoding human HNF-3 beta, a winged helix transcription factor, which also belongs to the same HNF-transcription cascade.

METHODS

The cDNA clone for human HNF-3 beta was isolated from a liver cDNA library. The gene was also cloned from a genomic library and its organization and chromosomal localization were determined. We screened 68 Japanese subjects with MODY/early-onset diabetes for mutations in this gene.

RESULTS

Human HNF-3 beta is composed of 457 amino acids. The human gene, which was mapped to the segment 30 cR from SHGC-37039 on chromosome 20p by radiation hybrid mapping, spans approximately 4.5 kb and consists of three exons. Direct sequencing of the exons and flanking regions identified one missense mutation A328 V and seven polymorphisms, although the functional significance of the mutation in the pathogenesis of diabetes is not known.

CONCLUSION/INTERPRETATION

The characterization of the structure of the HNF-3 beta gene and its mapping in the framework of markers will be helpful in genetic studies of the various forms of diabetes mellitus.

Formation, photodissociation and structure of chromium/phosphorus binary cluster ions

Chromium/phosphorus binary cluster ions, [Cr(n)P(m)](+/-), produced by laser (532nm) ablation on a tablet of well-mixed chromium and red phosphorus powder, were studied with a home-built tandem time-of-flight (TOF) mass spectrometer. The clusters thus formed are mostly rich in phosphorus. There is an odd-even oscillation in the intensity of the [CrP(m)](+) series, i.e. the mass peaks of even m are higher than those of odd m. The peaks of [CrP(4)](+) and [CrP(8)](+) are especially prominent, which may be ascribed to the specific stability of P(4) sub-structures. There are also some intense peaks in the spectrum assigned to [Cr(3)P(8)](+), [Cr(4)P(9)](+), [Cr(5)P(11)](+), [Cr(6)P(12)](+), [Cr(8)P(14)](+) clusters, etc., which have stable compositions. The stability of these species is consistent with a simple qualitative electronic structure model, in which the valence electrons of P are filled into the d orbitals of Cr. The photodissociation of some cluster ions was also studied. DFT calculations were performed on three small cluster ions to provide some insight into their structures. Copyright 2000 John Wiley & Sons, Ltd.

Enhanced immune response to the melanoma antigen gp100 using recombinant adenovirus-transduced dendritic cells

Glycoprotein 100 (gp100) is one of a series of well-characterized human melanoma-associated antigens expressed by most melanoma cells. Immunization of C57BL/6 mice with an adenovirus (Ad) vector encoding human gp100 (Adhgp100) has been shown to induce limited protective immunity against challenge with murine melanoma B16 cells. In the current study we determined whether gp100-specific immunity can be enhanced using bone-marrow-derived dendritic cells (DCs) transduced with Adhgp100 ex vivo. Subcutaneous injection of Adhgp100-infected DCs resulted in potent T-cell-mediated protective immunity and a greater than 80% reduction of established tumors when administered to B16 tumor-bearing hosts. Compared to direct injection of Adhgp100 vector alone, immunization with Adhgp100-infected DCs induced markedly greater antitumor activity. In vitro CTL analysis demonstrated that DC-Adhgp100 immunization activated both CD4(+) and CD8(+) CTLs, while no lytic activity was generated by vaccination with Adhgp100 alone. In vivo depletion of CD4(+) T cells, but not CD8(+) T cells, completely abrogated CTL activity, suggesting that Adhgp100-transduced DCs result in activation of both CD4(+) and CD8(+) CTLs via a CD4(+)-dependent mechanism. We speculate that this improved efficacy of Adhgp100-transduced DCs compared to direct immunization with Adhgp100 may be the result of direct DC-mediated CD4(+) T cell activation. These results emphasize the importance of CD4(+) T cells in the development of therapeutic antigen-specific cancer vaccines.

Extended half-life and elevated steady-state level of a single-chain Fv intrabody are critical for specific intracellular retargeting of its antigen, caspase-7

8 h) and high steady-state levels of protein accumulation, while the H2 intrabodies had a half-life of 2 h and less protein at steady state. These results suggest that the choice of sFv as an intrabody depends critically on the intracellular sFv protein having an extended half-life and elevated steady-state level. Thus, extended half-life must be considered together with sFv antibody specificity and affinity when choosing an optimal sFv intrabody for functional studies of cellular proteins.

[Detection of human papillomavirus gene in biopsies from colon carcinoma by PCR]

OBJECTIVE

To detect the human papillomavirus gene (HPVs) in biopsies from colon carcinoma by PCR and to study the relationship between HPV infection and colon carcinoma.

METHODS

46 biopsies from colon carcinoma, 10 biopsies from tissue around carcinoma and 16 control biopsies were collected and DNA were extracted. The HPV DNA in biopsies were amplified by PCR using general primers (GP) and primers for HPV6/11, HPV16/33 and HPV18.

RESULTS

20 out of 46 biopsies from colon carcinoma showed HPV gene positive, HPV6/11, HPV6/33 and HPV18 positivity were 3, 11 and 6 respectively. HPV DNA was found in 1 case from 10 biopsies of surrounding tissue of carcinoma. 16 control biopsies were negative.

CONCLUSION

HPV may be related to the etiology of colon carcinoma.

Effects of BRL 55 834 on allergen-induced bronchoconstriction and airway inflammation in sensitized guinea pigs

OBJECTIVE

To investigate the effects of potassium channel activator on allergen-induced bronchoconstriction and airway inflammation and to discuss which role it plays in asthma therapy.

METHODS

Airway insufflation pressure, examination of inflammatory cells in bronchial alveolar lavage fluid, analysis of airway pathology and airway Evans blue dye extravasation measurement were employed to detect airway resistance and airway inflammatory responses.

RESULTS

[(3s, 4R)-3, 4-dihydro-2, 2-dimethyl-4-(2-oxopiperidin-l-yl)-6-pentafluoroethyl-2H-1-benzopyran-3-ol] (BRL) 55 834 (8 micrograms/kg) inhibited not only ovalbumin-induced airway insufflation pressure increase but also inflammatory cell infiltration (ICI) in sensitized guinea-pigs; moreover, it did not decrease blood pressure; in contrast to BRL 55 834, single dose of BRL 38 227 (200 micrograms/kg) and verapamil (0.5 mg/kg) had a little effect on ICI; single dose of aminophylline (25 mg/kg) and dexamethasone (1 mg/kg) could not inhibit ICI, but the former could inhibit airway insufflation increase; drugs, besides aminophylline, could reduce microvascular leakage; single dose of BRL 38 227, verapamil and dexamethasone had no inhibition of airway insufflation pressure; BRL 38 227 and verapamil decreased blood pressure markedly.

CONCLUSIONS

Selective potassium channel activator BRL 55 834 not only decreases airway resistance, but also inhibit airway inflammation, and both of them are of benefit to asthma therapy.

[The effect of sandostatin on sphincter of Oddi in acute severe pancreatitis in dogs]

OBJECTIVE

To study the pressure change of sphincter of Oddi (SO) in acute severe pancreatitis (ASP) and the effect of sandostatin on it.

METHODS

Fifteen dogs were used and allocated into 2 groups: ASP untreated group and sandostatin group. The ASP model was prepared by retrograde ductal injection of a mixture of 5% taurocholic acid and autologous bile. SO manometic parameters including basal pressure (BP) and phasic contraction amplitude (PCA) were measured at each time spot before and after the preparation of ASP and after the administration of sandostatin.

RESULTS

BP was obviously increased after ASP preparation and sandostatin could significantly decrease the BP of SO in ASP group but not PCA.

CONCLUSION

Dysmotility of SO might play an important role in the severity and progression of ASP. Sandostatin may have beneficial effects in the treatment of ASP by decreasing BP of SO.

Origin of the suppression of chloride ion sensitivity in human embryonic hemoglobin Gower II

The molecular origin of the observed reduction of chloride ion sensitivity in the oxygen binding characteristics of the human embryonic hemoglobin Gower II has been probed by using site-directed mutant forms of the protein. Separate mutation of the three amino acids previously identified as candidates for the suppression of chloride sensitivity in the epsilon chain allowed us to unambiguously identify the His beta 77-->epsilon Asn as the origin of the lower sensitivity towards chloride ions in hemoglobin Gower II, which allows oxygen exchange from the mother to the late embryo under physiological conditions.

[Detection of human papillomavirus and herpesvirus genotypes in biopsy specimens from cervical carcinoma by PCR-endonuclease cleavage]

OBJECTIVE

This study was to detect the human papillomavirus (HPV) and herpes simplex virus (HSV) genotypes in biopsy specimens of cervical carcinoma and genital verruca by PCR-endonuclease cleavage.

METHODS

Biopsy samples of were obtained from 390 patients with cervical carcinoma, HPV and HSV genotypes were detected by PCR and endonuclease cleavage.

RESULTS

The results indicated that HPV types 16, 18, 35 were found in 152 (38.9%) of 390 cervical carcinoma, in 56 (31.8%) of 176 cervical erosion, while HPV types 6, 11 were found in 80 (58.8%) of 136 acuminate erruca. The HSV-2 type were found in 135 (34.6%) of 390 cervical carcinoma and in 33 (18.7%) of 176 cervical erosion. The HPV 16, 18, 35 types and HSV-2 type found in normal cervical secretions of the control group all were 3.2%, There was significant difference between the test group of cervical carcinoma and the control group of normal cervical secretion (P < 0.001 by x 2 analysis). The restriction endonuclease analysis of these amplified products showed that positive rates of HPV 16, 18, 35 types and HSV-2 type from cervical carcinoma were 23.3%, 14.6%, 1.0% and 34.6%, respectively. While HPV 6, 11 types from acuminate verruca were 36.0% and 22.8% positive respectively.

CONCLUSION

The results suggest that HPV 16, 18 types and HSV-2 type are associated with majority of the cervical carcinoma.

Membrane topology and cell surface targeting of microsomal epoxide hydrolase. Evidence for multiple topological orientations

Microsomal epoxide hydrolase (mEH) is a bifunctional membrane protein that plays a central role in the metabolism of xenobiotics and in the hepatocyte uptake of bile acids. Numerous studies have established that this protein is expressed both in the endoplasmic reticulum and at the sinusoidal plasma membrane. Preliminary evidence has suggested that mEH is expressed in the endoplasmic reticulum (ER) membrane with two distinct topological orientations. To further characterize the membrane topology and targeting of this protein, an N-glycosylation site was engineered into mEH to serve as a topological probe for the elucidation of the cellular location of mEH domains. The cDNAs for mEH and this mEH derivative (mEHg) were then expressed in vitro and in COS-7 cells. Analysis of total expressed protein in these systems indicated that mEHg was largely unglycosylated, suggesting that expression in the ER was primarily of a type I orientation (Ccyt/Nexo). However, analysis, by biotin/avidin labeling procedures, of mEHg expressed at the surface of transfected COS-7 cells, showed it to be fully glycosylated, indicating that the topological form targeted to this site originally had a type II orientation (Cexo/Ncyt) in the ER. The surface expression of mEH was also confirmed by confocal fluorescence scanning microscopy. The sensitivity of mEH topology to the charge at the N-terminal domain was demonstrated by altering the net charge over a range of 0 to +3. The introduction of one positive charge led to a significant inversion in mEH topology based on glycosylation site analysis. A truncated form of mEH lacking the N-terminal hydrophobic transmembrane domain was also detected on the extracellular surface of transfected COS-7 cells, demonstrating the existence of at least one additional transmembrane segment. These results suggest that mEH may be integrated into the membrane with multiple transmembrane domains and is inserted into the ER membrane with two topological orientations, one of which is targeted to the plasma membrane where it mediates bile acid transport.

Disruption of type IV intermediate filament network in mice lacking the neurofilament medium and heavy subunits

To clarify the role of the neurofilament (NF) medium (NF-M) and heavy (NF-H) subunits, we generated mice with targeted disruption of both NF-M and NF-H genes. The absence of the NF-M subunit resulted in a two- to threefold reduction in the caliber of large myelinated axons, whereas the lack of NF-H subunits had little effect on the radial growth of motor axons. In NF-M-/- mice, the velocity of axonal transport of NF light (NF-L) and NF-H proteins was increased by about two-fold, whereas the steady-state levels of assembled NF-L were reduced. Although the NF-M or NF-H subunits are each dispensable for the formation of intermediate filaments, the absence of both subunits in double NF-M; NF-H knockout mice led to a scarcity of intermediate filament structures in axons and to a marked approximately twofold increase in the number of microtubules. Protein analysis indicated that the levels of NF-L and alpha-internexin proteins were reduced dramatically throughout the nervous system. Immunohistochemistry of spinal cord from the NF-M-/-;NF-H-/- mice revealed enhanced NF-L staining in the perikaryon of motor neurons but a weak NF-L staining in axons. In addition, axonal transport studies carried out by the injection of [35S]methionine into spinal cord revealed after 30 days very low levels of newly synthesized NF-L proteins in the sciatic nerve of NF-M-/-;NF-H-/- mice. The combined results demonstrate a requirement of the high-molecular-weight subunits for the assembly of type IV intermediate filament proteins and for the efficient translocation of NF-L proteins into the axonal compartment.

[The complications of excimer laser in-situ keratomileusis for myopia]

OBJECTIVE

To analyze the complications of excimer laser in-situ keratomileusis (LASIK) for myopia, investigate the causes and discuss the prevention of these complications.

METHODS

The SCMD microkeratome and Schwind Keratom F excimer laser were used to correct myopia on 1,265 eyes in 662 cases. The eyes were divided into 3 groups: A: <or= -6.00 D in 726 eyes; B: -6.25 to -10.00 D, 287 eyes; C: > -10.00 D, 252 eyes. All of them were followed up for a period of 12 months.

RESULTS

Intraoperative corneal disk completely detached: 6 eyes (0.5%); corneal disk incomplete sectioned: 3 eyes (0.2%); corneal epithelial disk: 2 eyes (0.2%); corneal interface minute foreign metal bodies: 11 eyes (0.9%); postoperative steroid intraocular hypertension: 21 eyes (1.7%); macular hemorrhage: 2 eyes (0.2%). At postoperative 3 months, there was refractive regression > 1.00 D in 0.0%, 3.1% and 7.9% respectively in the 3 groups; the increase in astigmatism > 1.00 D, 0.4%, 2.8% and 4.4% respectively.

CONCLUSION

LASIK is a safe effective method for correcting myopia. Yet attention should be paid on the complications during and after operation. With the improvement in operative technique and better designed procedure, these complications can be decreased and the preoperative correctness in estimation of the postoperative results and the postoperative accuracy in the correction of myopia can be elevated.

Radical-Mediated Diastereoselective Construction of a Chiral Synthon for Synthesis of Dolabellanes

[reaction: see text] A useful trans-substituted multifunctional cyclopentane with a chiral quaternary center was selectively synthesized by free radical Michael addition to the (Z)-propionate or -malonate derivatives. The stereoselectivity could be reversed by changing the configuration of the double bond.

Proliferative activity as detected by immunostaining with Ki-67 and proliferating cell nuclear antigen in benign and malignant epithelial lesions of the human parotid gland

OBJECTIVE

A retrospective immunohistochemical study of parotid gland lesions was designed to evaluate the diagnostic and prognostic value of the proliferating cell nuclear antigen (PCNA) and Ki-67 with monoclonal antibodies PC 10 and MIB-1, respectively.

STUDY DESIGN

Tissue samples comprised normal parotid gland (N, n = 10), chronic sialadenitis (CS, n = 8), Warthin's tumor (W, n = 10), benign pleomorphic adenoma (BPA, n = 8), mucoepidermoid carcinoma (MEC, n = 13), carcinoma in pleomorphic adenoma (CPA, n = 8) and adenoid cystic carcinoma (ACC, n = 12). The morphometric parameters for PCNA and MIB-1 comprised the PI and MI labelling indices (the numerical percentage of positive nuclei), NAP and NAM (the numerical density of positive nuclei), and NPI and NMI (volume corrected index).

RESULTS

The values of MIB-1 parameters increased progressively in benign lesions in comparison with the N group and in malignant neoplasms in comparison with nonneoplastic groups and benign lesions. Values for all parameters in BPA were significantly lower than those in malignant groups. Spearman rank correlation analysis showed a highly positive correlation between the morphometric parameters and severity of the lesions. The mean values of MI and NMI were significantly higher in patients who died of the malignant tumors than in those who survived. The same quantitative parameters for PCNA did not differ significantly from those obtained for MIB-1 and showed similar trends.

CONCLUSION

PCNA and MIB-1 indices are reliable markers for discriminating between benign and malignant tumors of the parotid gland, and the parameters PI, MI, NPI and NMI may have prognostic applications.

Lignan and phenylpropanoid glycosides from Lancea tibetica and their antitumor activity

A new lignan glucoside, the first 7,9'-monoepoxyte-trahydrofuran type lignan with the cis-relationship of H-7 and H-8, named tibeticoside (1), as well as ten known compounds have been isolated from the medicinal plant (roots, stems and leaves) Lancea tibetica. The structure of tibeticoside (1) has been elucidated on the basis of chemical and spectral evidence, especially by 2D-NMR (1H-1H COSY, HMQC, HMBC, NOESY). In addition, sylvatesmin (6) exhibited effective antitumor activity on B16 cells.

The pleckstrin homology domain of the Wiskott-Aldrich syndrome protein is involved in the organization of actin cytoskeleton

In this study, we investigated the role of the pleckstrin homology (PH) domain of the Wiskott-Aldrich syndrome protein (WASP) in the regulation of actin cytoskeleton, which is defective in patients with Wiskott-Aldrich syndrome (WAS) and X-linked thrombocytopenia (XLT). Overexpression of the WASP in COS-7 cells cultured in the presence of fetal calf serum (FCS) resulted in large cluster formation of polymerized actin and WASP in the cytoplasm. In contrast, when the WASP transfected cells were cultured in the absence of FCS, activation with PMA or EGF was required to induce cluster formation. Overexpression of WASP with a missense mutation in the N-terminus of the PH domain failed to induce the large cluster formation in COS-7 cells even in the presence of FCS. We also found that phosphatidylinositol 4,5-bisphosphate (PIP(2)), which is known to regulate the actin cytoskeleton, binds to the PH domain of WASP, and the binding was abolished by the introduction of a missense mutation into the N-terminus but not the C-terminus of the PH domain. Together with the observations that most of the missense mutations observed in patients with WAS and XLT are located within the PH domain, these results indicate that the PH domain of WASP plays important roles in the regulation of actin cytoskeleton and suggested that the binding of PIP(2) to the PH domain is necessary for WASP to function properly.

Imager that combines near-infrared diffusive light and ultrasound

We introduce an imaging technique that combines complementary features of ultrasound and near-infrared diffusive light imaging. We achieve the combined technology experimentally by mounting an ultrasound array together with multiple laser source and optical detector fibers upon a hand-held probe. The technique is demonstrated with tissue phantoms wherein both acoustic and optical sensors image the volume underneath the probe. Coregistration of acoustic and optical images is achieved with an accuracy of 0.27+/-0.20cm, approximately half of the image pixel size of our prototype. Accurate determination of target optical absorption is also achieved by use of image segmentation on the ultrasound reconstruction. The combined technique may provide improved breast-cancer detection sensitivity and specificity.

[Preoperative staging of patients with primary ovarian carcinoma by CT and MRI]

OBJECTIVE

To investigate values and limitations of CT and MRI applied in staging of patients with primary ovarian carcinoma (POC).

METHODS

Forty two patients with POC proven by radical surgery, laparotomy, and postoperative pathology were studied. In comparison to surgical and pathological findings, sensitivity, specificity, and accuracy of CT, MRI and CT plus MRI were calculated. Staging by the three imaging methods was obtained according to FIGO's classification.

RESULTS

CT and MRI showed higher accuracy in evaluation of invasion to uterus (89.5% and 94.7%) and disease of Douglas pouch (94.7% and 97.4%). CT was to some extent superior to MRI in assessing ipsilateral or bilateral tumor and lesions related to peritoneal seeding; MRI, however, had better capability of diagnosing invasion to ovarian capsule, pelvic organs excluding bowel, nodules in Douglas pouch, and metastasis to lymph nodes. The overall accuracy of staging by CT, MRI, and CT plus MRI was 73.7%, 68.4%, and 70.6%, respectively (P > 0.05).

CONCLUSION

CT and MRI are useful imaging modalities in staging of POC, but low sensitivity for detecting involvement in some anatomic regions needs to be improved.

[Effects of vitamin A deficiency on the development and growth of rat embryos]

Effects of vitamin A deficiency on the development and growth of rat embryos were studied. Serious vitamin A deficiency markedly reduce body weight, body length and tail length, and induce incomplete development of skeleton and induce pathological change of brain and kidney of rat fetus. It was concluded that the development and growth of the embryos was affected and the brain and the kidney of fetus were damaged in serious vitamin A deficient rats.

Cytotoxic evaluation of root-end filling materials in cultures of human osteoblast-like cells and periodontal ligament cells

The cytotoxicity of three root-end filling materials (amalgam, IRM, and Super-EBA) was evaluated in cultures of human periodontal ligament cells and human osteoblast-like cells. Ten-millimeter-long plastic test tubes were filled with 3 mm of freshly mixed root-end filling materials at one end (1.5 mm diameter). The opposite end was sealed and attached by heat to a 35-mm cell culture dish. Human periodontal ligament cells and human osteoblast-like cells were seeded in the dishes. The size of cell-free zones around the root-end filling materials and the total cell number per dish were calculated after 3 and 7 days. Empty test tubes used as controls did not influence the growth and distribution of the cultured cells. Cell density increased in all groups in the test period. Amalgam had a larger cell-free zone, compared with IRM and Super-EBA and showed a reduction in total cell number per dish for both tested cell types. IRM and Super-EBA also had a cell-free inhibition zone for both cell types, but no significant reduction in total cell number per dish. This study showed that amalgam had a higher cell toxicity to human periodontal ligament cells and human osteoblast-like cells than IRM and Super-EBA.

Evolutionary relationships among seventeen human papillomavirus genotypes

The DNA and the protein sequences of the six major open reading frames (ORFs) of 17 human papillomavirus (HPV) genotypes have been carefully aligned. Conserved primary and probable secondary structural features of the proteins have been identified. From the analysis of variations in the aligned positions, the most consistent evolutionary relationships have been reconstructed for each gene and for the genomes as a whole. The L1 gene encoding the major capsid protein and the E1 gene encoding a replication protein are the most conserved. The hinge region in E2 is the most divergent. With varying degrees of sequence relatedness, the major groups and subgroups of HPV genotypes can be recognized, these clusters: the mucosotrophic virus types (33, 58), (16, (31, 35)), (18, 39), (51), (6b, 11); mucosal/cutaneous transitional virus types (2a, 57); and the cutaneous virus types (47, (5, 8)), (1a), (41), closely reflect epithelial tissue-type predilections and clinical pathogenicities.

No requirement of alpha-internexin for nervous system development and for radial growth of axons

Alpha-Internexin is a type IV intermediate filament protein that is expressed abundantly in neurons during development of the peripheral and central nervous systems as well as in few neurons of the adult central nervous system. It has been suggested that alpha-internexin may act as a scaffold for the formation of neuronal intermediate filaments during early development. In addition, recent reports suggest that alpha-internexin could play a major role in two degenerative neurological disorders. We report here an analysis of mice with a targeted disruption of alpha-internexin gene. Unexpectedly, alpha-internexin -/- mice developed normally and did not exhibit overt phenotypes. Moreover, the absence of alpha-internexin did not interfere with neurite extension of cultured DRG neurons. The number and caliber of L4 ventral root axons remained unchanged in alpha-internexin -/- mice. In the retina, alpha-internexin begins to be expressed in retinal ganglion cells when their first axons reach the optic chiasma. Using HRP tracer, we show that the projection pattern of the RGC axons is not modified by the absence of alpha-internexin. Electron microscopy did not reveal significant differences in axonal calibers, in myelination of axons and in neurofilament structures between alpha-internexin -/- and control mice during development and at adult stage. These data indicate that alpha-internexin is not required for the polymerization of neurofilament in vivo. Mice deficient for both alpha-internexin and neurofilament light chain (NF-L) exhibited no over phenotypes as well. No intermediate filament structures were detectable in optic nerve of alpha-internexin -/-; NF-L -/- mice. Ours results do not support the hypothesis of a role for type IV intermediate filaments in axonal outgrowth during development of nervous system.

[Detection of 8-hydroxyguanine in the DNA of the H2O2-treated HL-60 cells by GC/FID]

This paper describes the DNA damage by hydrogen peroxide in HL-60 cells and the detection of 8-hydroxyguanine produced. The number of cells was at least about 2 x 10(7)/sample. Treatment of HL-60 cells with 0.4 mmol/L hydrogen peroxide for 24 h would result in DNA damage. The DNA samples were isolated, then qualitatively and quantitatively analyzed before hydrolysis. The results of experiments showed that 100-300 microL 98% formic acid could hydrolyze about 0.12 mg DNA samples completely in 150 degrees C for 1 h. After lyophilizing the DNA samples for 6-8 h, one DNA sample was trimethylsilylated completely with 150 microL BSTFA in 150 degrees C for 1 h. The recovery of trimethylsilylated 8-hydroxyguanine was 81.70%. The trimethylsilylated 8-hydroxyguanine was identified by GC/FID and CGC/MS-SIM parallely.

[Biomechanical evaluation of five fixation techniques for the lower cervical spine]

OBJECTIVE

This study biomechanically investigated the three-dimensional motion stability of five reconstruction methods in the cervical spine, in order to provide the biomechanical basis for the clinical selection of fixation methods.

METHODS

With eight adult cervical spine fresh specimens, the three-column injury was produced at C(4 - 5) level. The spinal constructs, reconstructed by various techniques including anterior titanium locking screw plate (TLSP), posterior interspinous wiring (IW), combined fixation with the TLSP and IW (TLSP + IW), Roy-Camille plate (RP), and transpedicular screw plate (TP), were tested under six loading modes-flexion, extension, right/left lateral bending, and right/left axial rotation.

RESULTS

The three-dimensional motion stability of either TLSP or IW was less than that of intact cervical spine. The TLSP + IW and RP provided increased stability compared with the intact spine. The stabilizing capabilities of transpedicular screw plate fixation was the best in all loading modes.

CONCLUSIONS

In three-column instability of cervical spine injury, exclusive use of the anterior plate or the posterior interspinous wiring was not supported by the results. The stabilizing capabilities provided by combined anterior and posterior instrumentation and posterior plate were good. The three-column fixation for the cervical spine using transpedicular screw plate fixation offers increased stability significantly over that of other conventional cervical fixation systems.

Primary choledochorrhaphy after common bile duct exploration

AIM

To prove further the safety of primary closure of the common bile duct.

METHOD

Twenty patients among 99 common bile duct explorations underwent primary closure. Pre- and postoperative liver function test, ultrasound and intraoperative cholangiography data, operation time, postoperative complications and the length of postoperative stay were recorded.

RESULTS

Nineteen patients did not suffer any biliary complication. One had bile leakage and bile peritonitis, and another had duodenal leakage. One case was complicated by gastric ulcer perforation. The mean postoperative hospital stay except for the 2 patients with complications was 8.72 +/- 0.75 days. Preoperative abnormal liver function tests recovered within 2-3 weeks after the operation. Postoperative ultrasound scan of the biliary tract within 2 months revealed no stenosis and residual stone.

CONCLUSION

Primary common bile duct closure is a safe alternative to routine biliary drainage in selected patients.

Interpreting patterns of gene expression with self-organizing maps: methods and application to hematopoietic differentiation

Array technologies have made it straightforward to monitor simultaneously the expression pattern of thousands of genes. The challenge now is to interpret such massive data sets. The first step is to extract the fundamental patterns of gene expression inherent in the data. This paper describes the application of self-organizing maps, a type of mathematical cluster analysis that is particularly well suited for recognizing and classifying features in complex, multidimensional data. The method has been implemented in a publicly available computer package, GENECLUSTER, that performs the analytical calculations and provides easy data visualization. To illustrate the value of such analysis, the approach is applied to hematopoietic differentiation in four well studied models (HL-60, U937, Jurkat, and NB4 cells). Expression patterns of some 6,000 human genes were assayed, and an online database was created. GENECLUSTER was used to organize the genes into biologically relevant clusters that suggest novel hypotheses about hematopoietic differentiation-for example, highlighting certain genes and pathways involved in "differentiation therapy" used in the treatment of acute promyelocytic leukemia.

Future of bradyarrhythmia therapy systems: automaticity

Since the first fixed-rate ventricular pacemaker was introduced in the late 1950s, pacing systems have evolved rapidly. Current developments focus on making devices more sophisticated and less complex--a challenging combination. Automaticity features such as beat-by-beat capture verification, sensitivity threshold adaptation, and algorithms to govern dynamically the maximum sensor rate have either recently been introduced or are likely to be introduced in the near future. Technologic advances are likely to allow meaningful improvements in current drain, battery performance, memory capacity, signal processing, telemetry, and programmer interface. Bradyarrhythmia therapy devices of the future promise to go beyond the pacemaker. Ultimately, pacing systems will become part of integrated cardiac rhythm management systems.

Stereological evaluation of mouse prostate development

A stereological study of the development of the mouse prostate was undertaken between the second week of postnatal life and maturity. The aim was to quantify the progressive changes in the size and areal density of the ventral prostate gland components during development. Male mice were studied at weekly intervals from days of life 15 to 49 for organ and body weights, ductal branching, diameters of ventral prostate ducts and lumen and volume densities of epithelium, lumen, and stroma. Ductal branch-tip numbers were maximal at 35 days of age, while prostate weights increased linearly with age and did not reach a plateau at 49 days. Prostatic glandular and luminal diameters both showed a continuous increase until day 49. At 5 weeks of age, there was a decrease in the volume density of prostatic epithelium accompanied by a simultaneous increase in the volume density of the lumen. This study indicates that prostate-branching morphogenesis is complete by the fifth week in mice but that further growth of the prostate continues due to the increase in ductal dimensions. Qualitatively, the ventral prostate in mice is fully mature by 5 weeks, and this histological maturity coincides with the completion of branching morphogenesis.

Estimation of tendon moment arms from three-dimensional magnetic resonance images

New three-dimensional (3D) magnetic resonance imaging (MRI) methods for measuring the tendon moment arm were created and were evaluated on the tendon moment arm of the flexor digitorum profundus at the third metacarpophalangeal joint. Using an open magnet MRI system and a hand holder, a series of static images were acquired at four joint angles and analyzed using specially created computer programs. Three methods were evaluated: (1) a 3D tendon excursion method that extended the method of Landsmeer; (2) a 3D geometric method whereby the moment arm was the perpendicular distance between the joint axis of rotation and the tendon path, and (3) a two-dimensional (2D) geometric method whereby single image slices were analyzed. Repeating the imaging and measurement processes, the 3D tendon excursion method was more reproducible (6% variation) than the 3D geometric method (12%), and both were much more reproducible than the 2D geometric method (27%). By having three operators analyze a single set of image data, we found that the precision of the 3D tendon excursion method was much less affected by segmentation error than the 3D geometric method. With the 3D imaging methods, tendon bowstringing and a displacement of the joint center of rotation toward the dorsal side of the hand were evident, leading to as much as a 60% increase in moment arm with joint flexion. Because of the dependence on flexion and variation between subjects, we recommend patient-specific measurements for target applications in functional neuromuscular stimulation interventions and tendon transfer surgery.

Traumatic instabilities of the cervical spine caused by high-speed axial compression in a human model. An in vitro biomechanical study

STUDY DESIGN

Traumatic injury of the cervical spine was produced on human cadavers and evaluated with instability tests and radiographs.

OBJECTIVE

To relate traumatic injuries of the cervical spine to instability and patterns of traumatic injury to different levels of impact energy.

SUMMARY OF BACKGROUND DATA

Data from young human cadavers are rare in traumatic models of the cervical spine, and instabilities caused by axial compression with different impacts remain unknown.

METHODS

Fourteen cervical spine specimens (C2-C4) obtained from fresh human cadavers were divided evenly into two groups and subjected to axial compressive impact with 30 J and 50 J impact energy, respectively. Pure moments in flexion-extension, left/right lateral bending, and left/right axial rotation were applied to each specimen before and after trauma. The maximum moment was 2.0 Nm in each case. Ranges of motion and neutral zones were measured using stereophotogrammetry.

RESULTS

Ranges of motion and neutral zones for both groups increased after trauma. No bony injury was observed on the radiographs after trauma with 30 J, but motions increased significantly in flexion, extension, and axial rotation. All specimens showed bony injuries after trauma with 50 J, whereas motions continued to increase significantly in all directions. The relative neutral zone values were larger than the corresponding range of motion values, except in flexion-extension after trauma with 50 J.

CONCLUSIONS

The injury patterns of the cervical spine were associated with impact energy, and a high level of impact energy could produce either three-column injury or anterior middle-column injury. Instabilities of the cervical spine caused by compressive trauma increased with the level of impact energy. The neutral zone was more sensitive than the range of motion in representing spinal instability, whereas instability testing was more sensitive than radiographs in evaluating traumatic injury of cervical spine.

[Joint rotational analysis of twenty six bands of the H2(80) Se molecule]

This paper expressed the theory of Global fit model. Global fit of all known up today rotation-vibration energies of twenty four states of the H2(80) Se molecule had been made, and the corresponding set of 112 parameters, which reproduce the initial 3516 upper energies with the mean accuracy of 10.6 x 10(-3) cm(-1), were obtained. On this base fine rotational structures of the local-mode bands (500, A1) and (401, B2) were analyzed with 252 upper energies, which were analyzed in the normal-molde and local-mode also. In the end, with the results above, joint rotation-vibration energies of twenty six states of H2(80) Se molecule were made, and the corresponding set of 114 parameters obtained, which reproduce the initial 3768 upper energies with the mean accuracy of 9.62 x 10(-3) cm(-1).