Childhood incidence of acute lymphoblastic leukaemia and exposure to broadcast radiation in Sydney--a second look

INTRODUCTION

Recent findings of an apparent association between incidence of childhood leukaemia and radio frequency radiation (RFR) from television transmission antennas in Sydney, NSW, are examined.

METHODS

Incidence of childhood (0-14 years) acute lymphoblastic leukaemia (ALL) at the local government area (LGA) level is related to estimated exposure levels of RFR from television transmission antennas, using Poisson regression techniques.

RESULTS

Most of the association between ALL incidence and television transmission RFR is shown to be the result of an influential observation: one of the highly exposed LGAs contributes all the excess, while in a similarly exposed LGA childhood ALL incidence was found to be no higher than the rate expected for NSW. With the influential observation excluded from the analysis, no positive correlation between exposure to RFR and leukaemia is evident. Conversely, under the assumption of an association with RFR, the low probability of the observed incident cases in LGAs under conditions of relatively high exposure to RFR conflicts with the assumption of an effect.

CONCLUSION

The apparent association between childhood ALL incidence and RFR radiation from television towers is weaker when an LGA-level analysis is conducted.

[Study of HDV infection in Shandong province]

To understand the situation of HDV infection in Shandong province and to explore the relationship between HDV and HBV infections, 2681 samples infected with HBV were tested for serum anti-HDV with enzyme linked immunosorbent assay, in Shandong. Among them, 207 (7.72%) were found to be anti-HDV positive. Anti-HDV positive rates in HBsAg carriers and in hepatitis B patients were 3.16% and 13.15%, respectively. A significant difference (P < 0.001) was noticed between the two groups. In the second group, anti-HDV positive rates in patients with chronic active hepatitis and severe hepatitis were both higher than those in patients with acute hepatitis and chronic persistent hepatitis and the difference was significant (P < 0.001). The longer the history and the more severe the condition the higher of the anti-HDV positive rate was seen. The results indicated that the combined and over-lapping HDV infections were both responsible for the chronic status of hepatitis B and its deterioration.

Involvement of p85 in p53-dependent apoptotic response to oxidative stress

Reactive oxygen species have damaging effects on cellular components and so trigger defensive responses by the cell and even programmed cell death, although the mechanisms by which mammalian cells transmit signals in response to oxidative damage are unknown. We report here that the protein p85, a regulator of the signalling protein phosphatidyl-3-OH kinase (PI(3)K), participates in the cell death process that is induced in response to oxidative stress and that this role of p85 in apoptosis does not involve PI(3)K. We show that disruption of p85 by homologous recombination impairs the cellular apoptotic response to oxidative stress. Because the protein p53 is required for cell death induced by oxidative damage, we examined the relation between p85 and p53. Using a chimaeric p53 fusion protein with the oestrogen receptor (p53ER) to supply p53 (p53 is induced upon binding of p53ER to oestradiol) in a p53-deficient cell line, we found that p85 is upregulated by p53 and that its involvement in p53-mediated apoptosis is independent of PI(3)K. We propose that p85 acts as a signal transducer in the cellular response to oxidative stress, mediating cell death regulated by p53.

Experimental cryptorchidism induces testicular germ cell apoptosis by p53-dependent and -independent pathways in mice

Cryptorchidism is associated with male infertility: germ cell loss occurs by apoptosis in response to elevated temperature. Since the tumor suppressor p53 is highly expressed in the testis and is known to induce apoptosis, an investigation was undertaken to establish whether heat stress causes p53-mediated germ cell apoptosis. Using a mouse model of experimental unilateral cryptorchidism, it was observed that testicular weight reduction, germ cell loss, and DNA fragmentation all began in the cryptorchid testes on Day 6-7 in wild-type mice. In contrast, these changes were delayed by 3 days in p53-/- mice. These results suggest that abdominal heat stress induces germ cell loss through two apoptotic pathways: a p53-dependent pathway responsible for the initial phase of germ cell apoptosis, and a p53-independent pathway that accounts for subsequent apoptosis.

Mapping and characterization of a novel cochlear gene in human and in mouse: a positional candidate gene for a deafness disorder, DFNA9

Previously we identified a partial human cDNA for a novel cochlear transcript, hCoch-5B2 (HGMW-approved symbol D14S564E), using subtractive hybridization techniques. Herein we report isolation and characterization of both human and mouse (D12H14S564E) cDNAs for Coch-5B2. Full-length Coch5B2 deduced amino acid sequences reveal a very high degree of conservation in the coding region (89% nucleotide and 94% amino acid identity and a potential signal peptide and two regions of extensive homology to the collagen-binding type A domains of von Willebrand factor, also present in other secreted proteins, including extracellular matrix components. High levels of hCoch-5B2 expression are seen only in human fetal inner ear structures, cochlea, and vestibule, among a large panel of human fetal and adult tissues. Coch-5B2 expression in the mouse is more widespread than in the human, with message detected in mouse adult spleen, cerebrum, cerebellum/medulla, and thymus. In both species very low level expression is detected in total eye. More specifically, mouse retina shows a higher level of mCoch-5B2 message than sclera and choroid. We have mapped hCoch-5B2 to human 14q11.2-q13 by somatic cell hybrid analysis and FISH and, more precisely, using radiation hybrids to a region of markers linked to DFNA9, a nonsyndromic autosomal dominant sensorineural hearing loss with vestibular defects. Furthermore, we detect hCoch-5B2 on three overlapping YACs, two of which also contain one of the markers linked to DFNA9. mCoch-5B2 was genetically mapped in the mouse to chromosome 12, in a region of homologous synteny with human 14q11.2-q13, which contains the asp1 (audiogenic seizure prone) locus in the mouse.

An ancient conserved gene expressed in the human inner ear: identification, expression analysis, and chromosomal mapping of human and mouse antiquitin (ATQ1)

We constructed and screened a human fetal cochlear cDNA library to identify genes involved in hearing and deafness. From this library we isolated a cDNA corresponding to the highly conserved ancient gene antiquitin (ATQ1). The plant homolog of ATQ1 is thought to be involved in regulating turgor pressure, a function that also would be essential for cells of the mammalian cochlea. Northern blots of 13 human fetal tissues show antiquitin to be highly expressed in cochlea, ovary, eye, heart, and kidney. Using RT-PCR of rat cochlear hair cell-specific cDNA libraries, we detect antiquitin expression in outer hair cells, but not in inner or vestibular type 1 hair cells, suggesting that antiquitin is not expressed ubiquitously in the cochlea. Human ATQ1 was mapped to human chromosome region 5q31 using fluorescence in situ hybridization, and mouse ATQ1 was mapped to mouse chromosome 18 by single-strand conformation polymorphism mapping of interspecific backcross progeny DNAs. Four human antiquitin-like sequences, possibly pseudogenes, were also identified and mapped.

Promoter elements required for phloem-specific gene expression from the RTBV promoter in rice

Previous studies indicated that a DNA fragment comprising nucleotides (nt) -164 to +45 of the RTBV promoter is sufficient to drive phloem-specific expression of a reporter gene in transgenic rice plants. In addition, two potential cis elements, Box I (nt -3 to +5) and Box II (nt -53 to -39) were identified by DNA-protein interaction assays. In this study, the results of further in vivo studies involving mutagenesis of selected DNA sequences and analysis of expression of a reporter gene in transgenic rice plants revealed that, in addition to Box I and Box II, other elements are required for phloem-specific gene expression, among which are a direct repeat (ASL Box, nt -98 to -79) and a GATA motif (nt -143 to -135). All the these elements bind rice nuclear factors specifically, and mutations of the elements were identified that resulted in loss-of-competition in electrophoretic mobility shift assays. A DNA fragment comprising nt -164 to -32, which contains Box II, the ASL Box and the GATA motif, conferred phloem-specific reporter gene expression independent of Box I when fused to a heterologous CaMV 35S minimal promoter and introduced to transgenic rice plants. Studies that introduced point mutations suggested that in the context of the -103 to +45 promoter fragment, Box II and the ASL Box act synergistically to confer tissue-specific gene expression. Similar studies in the -164 to +45 promoter fragment indicated that the -164 to -103 region, which includes the GATA motif, contains sequences that are functionally redundant with those in the -103 to -32 region, including the ASL Box and Box II. It is concluded that these regions act additively to direct phloem-specific gene expression.

Imaging of the hand and wrist

This article reviews many of the most commonly used modalities for imaging the hand and wrist. Particular attention is paid to proper radiographic positioning, with emphasis on the four-view wrist series. Standard wrist measurements are detailed, and wrist arthrography is also discussed. Techniques for cross-sectional imaging, computed tomography, and MR imaging are reviewed, and several examples are presented as to where MR imaging is diagnostically valuable.

RF2a, a bZIP transcriptional activator of the phloem-specific rice tungro bacilliform virus promoter, functions in vascular development

Rice tungro bacilliform virus (RTBV) replicates only in phloem cells in infected rice plants and its promoter drives strong phloem-specific reporter gene expression in transgenic rice plants. We isolated a cDNA encoding a basic leucine zipper (bZIP) protein, RF2a, which binds to the Box II cis element that is important for expression from the promoter. RF2a, which stimulates Box II-dependent transcription in a homologous in vitro transcription system, accumulates in nuclei of phloem and certain other cell types in shoots, but is found at only very low levels in roots. Transgenic antisense plants in which RF2a accumulation was suppressed had normal roots but stunted, twisted leaves with small, disorganized vascular bundles, an enlarged sclerenchyma and large air spaces. We propose that the RTBV promoter exploits a host transcription factor that is critical for leaf tissue differentiation and vascular development for its expression.

Ligamentous instabilities of the wrist

Carpal ligament instabilities are conditions in which the individual carpal bones have become unstable due to abnormal ligament support. Early diagnosis of ligamentous wrist instabilities is important because late diagnosis or failed diagnosis may lead to severe complications such as osteoarthritis. This article reviews the most common ligamentous instability patterns of the wrist and focuses on how to perform and obtain radiograms which will allow reliable diagnosis of wrist instabilities.

TLS (FUS) binds RNA in vivo and engages in nucleo-cytoplasmic shuttling

TLS, the product of a gene commonly translocated in liposarcomas (TLS), is prototypical of a newly identified class of nuclear proteins that contain a C-terminal domain with a distinct RNA recognition motif (RRM) surrounded by Arg-Gly-Gly (RGG) repeats. Its unique N terminus serves as an essential transforming domain for a number of fusion oncoproteins in human sarcomas and leukemias. In this study we use an in vivo UV crosslinking procedure to probe the interactions of TLS with RNA. TLS is found to bind RNA in vivo and the association of TLS with RNA is rapidly diminished by treating cells with transcriptional inhibitors. This suggests that the species bound by TLS turns over rapidly. Surprisingly, the RRM was found to be dispensable for RNA binding by TLS in vivo, suggesting that at any one time most of the interactions between TLS and RNA in the cell are not sequence specific. Analysis of inter specific heterokaryons formed between human and mouse or Xenopus cells revealed that TLS engages in rapid nucleocytoplasmic shuttling, a finding confirmed by the ability of anti-TLS antibodies to trap TLS when injected into the cytoplasm of HeLa cells. Cellular fractionation experiments suggest that TLS binds to RNA in both the nucleus and cytoplasm and support the hypothesis that TLS functions as a heterogeneous ribonuclear protein (hnRNP)-like chaperone of RNA. These findings are discussed in the context of the role altered forms of TLS play in cellular transformation.

p53 is associated with the nuclear envelope in mouse testis

p53 has been postulated to play a role in meiosis as well as in the regulation of germ cell numbers by apoptosis. This study investigated the subcellular localization of p53 in the testis, including conditions known to induce germ cell apoptosis. Western blot analysis showed that p53 was enriched in the nuclear envelope fraction, and confocal microscopy confirmed that p53 was associated with the nuclear envelope of germ cells. Exposure of the testis to heat stress induced translocation of p53 into the nucleus. Nuclear envelope binding provides an optimal site for rapid entry of p53 into the nucleus, where it may act as a DNA-binding protein to induce apoptosis or cell cycle arrest in response to appropriate stimuli. The nuclear envelope sequestration of p53 also provides a framework to understand how mitosis and meiosis in the testis may proceed despite high intracellular concentration of p53.

Temperature-mediated germ cell loss in the testis is associated with altered expression of the cell-cycle regulator p53

The dependence of spermatogenesis on the relatively cool environment of the scrotum is well known, and recent work has shown that germ cells undergo apoptosis upon exposure to abdominal temperature. p53 is a potent inducer of apoptosis and regulator of cell growth, and is found in high concentrations in the testis. The purpose of this study was to determine whether exposure of the testes to suprascrotal temperature was associated with alterations in testicular p53 expression. Male adult CD-1 mice were rendered unilaterally cryptorchid by surgically fixing one testis to the anterior abdominal wall while leaving the contralateral tests in the scrotum to serve as the euthermic control. p53 expression was evaluated in the cytoplasmic, soluble nuclear, and insoluble fractions by Western blot analysis with the monoclonal p53 antibody pAb240. The weights of the scrotal testes were unchanged over the 15 day study period. The weights of the cryptorchid testes remained stable for 7 days and then decreased by approximately 40% over the next two days. Histological evidence of germ cell loss was evident only after day 7. Altered expression of p53 protein in the cryptorchid testis was noted beginning on day 7, and consisted of the expression of a new 47 kD isoform of p53 in the cytosolic form and a 30 kD isoform in the soluble nuclear fraction. Scrotal testes showed no changes at any time point. These results demonstrate altered expression of the regulatory protein p53 beginning 1-2 days prior to the onset of germ cell loss following experimental unilateral cryptorchidism. Given the known function of p53 as an inducer of apoptotic cell death, these observations suggest a significant role for p53 in temperature-mediated germ cell loss.

Heat stress causes testicular germ cell apoptosis in adult mice

An investigation was undertaken to determine whether the germ-cell loss associated with exposure of the testis to abdominal temperature occurs by apoptosis. Using an adult-mouse model of experimental unilateral cryptorchidism, it was observed that DNA fragmentation, consistent with apoptosis, was observed on day 6 in the cryptorchid testis, with subsequent loss of testicular weight, histologic evidence of germ-cell loss, and histochemical staining of apoptotic germ cells observed on day 7. Vacuolization of the germinal epithelium and the appearance of multinucleated giant cells was noted synchronously with the onset of germ-cell loss. Histochemical staining for apoptosis was noted most frequently among the primary spermatocytes and round spermatids. These results indicate that the testicular germ-cell loss observed with exposure to abdominal heat stress occurs by apoptosis. Further investigation of the biochemical mechanisms involved in testicular apoptosis may provide strategies to address a variety of male reproductive issues such as contraception and infertility.

Parallel optical negabinary arithmetic based on logic operations

On the basis of signed-digit negabinary representation, parallel two-step addition and one-step subtraction can be performed for arbitrary-length negabinary operands. The arithmetic is realized by signed logic operations and optically implemented by spatial encoding and decoding techniques. The proposed algorithm and optical system are simple, reliable, and practicable, and they have the property of parallel processing of two-dimensional data. This leads to an efficient design for the optical arithmetic and logic unit.

A model for the initiation and growth of extracellular lipid liposomes in arterial intima

There is considerable evidence that lipoprotein cholesterol, after crossing the arterial endothelium and entering the intima from the vascular lumen, lodges in extracellular lipid packets (labeled "liposomes") bound to the extracellular matrix. These liposomes appear to form by occasional attachment of a low-density lipoprotein (LDL) to the intimal matrix and to grow in place mainly by appending available free LDL. The liposome size distributions observed in chronically hypercholesteremic (WHHL) and in short-term cholesterol-fed rabbits are quite different. We propose a hierarchy of simple nucleation-polymerization models to describe liposome formation and growth. Even the simplest of these (with only one adjustable parameter) agrees extremely well with the WHHL data. In contrast, the cholesterol-fed rabbit data seem to result from the short-term nonuniform intimal history of LDL supply, which is a consequence of the focal nature of the transendothelial LDL flow through isolated transient leakyjunctions. The same models used for the WHHL data, together with this intimal nonuniformity, superimposed on a slow uniform transendothelial seepage also account very well for this cholesterol-fed rabbit data.

A topogenic role for the oncogenic N-terminus of TLS: nucleolar localization when transcription is inhibited

TLS (FUS) and the related gene EWS encode the N-terminal portion of many fusion oncoproteins involved in human sarcomas and leukemia. TLS is an RNA-binding nuclear protein that is identical to hnRNP P2 and may be implicated in mRNA metabolism. When RNA polymerase II is inhibited, TLS immunostaining in the nucleus is dramatically altered, from its normal diffuse nucleoplasmic pattern to accumulation in dense nuclease-resistant aggregates. Co-immunostaining with antibodies to fibrillarin or p80 coilin and immunoelectron microscopy revealed that the TLS aggregates are associated with the nucleolus and are distinct from other known structures such as the coiled body or the interchromatin granule. Injection of cells with an oligodeoxynucleotide that disrupts splicing does not result in redistribution of TLS, indicating that the event is specific to inhibition of transcription. Oncoproteins that contain the N-terminal domain from either TLS, EWS or their Drosophila homologue, SARFH (CAZ), are also targeted to the same structure. These findings suggest a correlation between the topogenic and transforming activities of TLS and EWS N-termini and imply the existence of cellular targets that are shared by the germ-line encoded proteins and their oncogenic derivatives.

Pharmacokinetics and pharmacodynamics of ranitidine in renal impairment

OBJECTIVE

The pharmacodynamics and pharmacokinetics of ranitidine were examined in subjects with varying degrees of renal function to determine the effect of this condition on acid-antisecretory activity.

METHODS

Subjects with creatinine clearances (Ccr) ranging from 0 to 213 m1.min-1 received single 50-mg and 25-mg i.v. doses of ranitidine. This was followed by determination of serum and urine ranitidine concentrations, and continuous gastric pH monitoring for 24 h.

RESULTS

Serum ranitidine concentrations were described by a two-compartment model linked to a sigmoidal Emax model describing gastric pH. Ranitidine renal clearance, ranging from 0 to 1003 m1.min-1, correlated with CPAH (r2 = 0.707), while non-renal clearance was unaltered. Steady-state volume of distribution decreased by half in severe renal impairment. No changes in the effective concentration at half-maximal response (EC50), maximal response (Emax), or basal response (E0) were observed. Thus, renal elimination of ranitidine declined in parallel with renal function, while sensitivity to the pharmacologic effect (gastric pH elevation) was unaltered. Ranitidine was cell tolerated in these renally impaired subjects.

CONCLUSION

These data indicate that the current recommendation for renal impairment dose reduction (by two-thirds when Ccr < 50 m1-min-1) might result in under-treating moderately impaired patients, and suggests a less conservative dose reduction (by half when Ccr < 10 m1.min-1) to avoid therapeutic failure while remaining within the wide margin of safety for this drug.

[Treatment of nerve root avulsion of brachial plexus by nerve transfer]

The results of nerve transposition for root avulsion of brachial plexas in 21 cases were reported. The methods of the nerve transposition were divided into four groups as followings: By transfer of phrenic nerve, accesory nerve, the motor branches of cervical plexus and intercostal nerves in cease; By transfer of phrenic nerve, accessory nerve and the motor branches of cervical plexus in 6 cases; By transfer of phrenic nerve and accessory nerve in 9 cases, and by transfer of phrenic nerve or the motor branches of cervical plexus or intercostal nerve in 5 cases. During operation, in 1 cases variation of the brachial plexus was found. Injury to the subclavian artery occurred in 4 cases and they were repaired, which is good for the blood circulation of the upper arm and nerve regeneration. Nineteen cases were followed up with good results. The overall excellent and good rate was 73.7%. It was considered that transposition of nerve should be a routine operation for the treatment of root avulsion of brachial plexus and the accompanied arterial injury should be repaired at the same time during operation, and the latter would be advantageous to enhance functional recovery of nerve.

Surgeons' decision making in patients with chronic wrist pain: role of bilateral three-compartment wrist arthrography--prospective study

PURPOSE

To determine if wrist arthrography changes surgeons' diagnoses and treatment plans for patients with chronic wrist pain.

MATERIALS AND METHODS

Bilateral, three-compartment wrist arthrography was performed in 64 patients. Prospective questionnaires evaluated surgeons' diagnoses and management plans at three stages: before arthrography, after arthrography of the symptomatic wrist, and after arthrography of the asymptomatic wrist.

RESULTS

Surgeons tended to plan more conservative management after receiving the results of arthrography. The number of patients for whom the reported treatment plan included surgery dropped from 28 of 64 patients (44%) to 19 of 64 patients (30%) after review of the arthrography results (P = .05). The number of patients for whom the treatment plan included treatment of any kind dropped from 55 of 64 patients (86%) to 49 of 64 patients (77%) after review of the arthrography results (P = .09). An overall change in treatment plan occurred in 29 of 64 patients (45%).

CONCLUSION

Wrist arthrography influences surgeons' decision making. After reviewing the results of arthrography, surgeons tended to change treatment plans toward more conservative, less invasive treatment.

Pharmacokinetics of bismuth and ranitidine following single doses of ranitidine bismuth citrate

1. The pharmacokinetics of bismuth and ranitidine derived from ranitidine bismuth citrate given in single oral doses ranging from 200 mg to 1600 mg were evaluated in healthy subjects. 2. Bismuth was only minimally absorbed (< 0.5% of the amount dosed) after administration of ranitidine bismuth citrate, and peak plasma concentrations never exceeded 33 ng ml-1 in any subject. Plasma concentrations and urinary recoveries of bismuth at doses up to and including 800 mg were relatively constant and not proportional to dose. Bismuth absorption was increased more than proportionally with the dose at 1600 mg. 3. The pharmacokinetics of ranitidine after administration of ranitidine bismuth citrate were dose-proportional and consistent with previous observations for ranitidine administered alone. 4. Ranitidine bismuth citrate was well-tolerated in single oral doses of up to 1600 mg.

[Finite element stress analysis of stress distribution endodontic posts at shoulder]

The objective of the present resarch is the comparative stress distribution of various design for post-core at shoulder. The purpose of this study was to analyse the stress distribution and concentration in the dentin of paralled-sided and taped posts by different shoulder designs with finite elements stress analysis method. It was found that stress tended to concentrate under the core shoulder with vertical force. When the force applied from the linqual side. The stress concentrated at the buccal side. The 90 degrees shoulder angles exhibited more even stress distribution than sharp shoulder angles. The analysis revealed that sharp angle should be avoided as occlusal shoulder in clinical practice because this design are less resistant to forces applied on them and are susceptible to fractures in the dentin.

Incomplete factorial and response surface methods in experimental design: yield optimization of tRNA(Trp) from in vitro T7 RNA polymerase transcription

We have studied the yield of Escherichia coli tRNA(Trp) obtained from in vitro T7 RNA polymerase transcription using incomplete factorial and response surface methods. Incomplete factorial experiments were first used to estimate the relative impact of six variables on the yield of tRNA(Trp). Fifteen trials were performed according to a balanced and randomized design. The correlation between observed yield and all experimental variables was identified by stepwise multiple linear regression analysis. The concentrations of T7 RNA polymerase, DNA template, NTP and MgCl2 proved to be significantly correlated with the yield of tRNA(Trp). We then optimized the yield with respect to each of these four variables simultaneously with a designed, response surface experiment based on the Hardin-Sloane minimum prediction variance algorithm. Twenty experiments were performed, in duplicate, to sample the quadratic surface relating the yield to the four significant variables. Coefficients of the quadratic function with all two-factor interactions were evaluated by stepwise regression using least squares, and significant coefficients were retained. Partial differentiation of the resulting quadratic model showed it to possess an optimum. Transcription performed at the corresponding conditions yielded 6-fold more tRNA(Trp) than the initial conditions, confirming the predictive value of the experimentally determined response surface.

Imaging of pelvic insufficiency fractures

Insufficiency fractures of the pelvis are being increasingly recognized as a major cause of low back pain in elderly women with osteoporosis. Fractures in the sacrum are difficult to diagnose, as plain radiographic findings are either unhelpful or misleading. Bone scintigraphy is very sensitive for the detection of fractures in the sacrum, with demonstration of the H-shaped (or butterfly) sacral pattern or the combination of concomitant sacral and parasymphyseal uptake being considered as characteristic of insufficiency fractures. Computed tomography (CT) is helpful for confirming the presence of fractures in cases with atypical scintigraphic patterns, particularly in those with a known primary malignant neoplasm. CT is especially useful in the further evaluation of parasymphyseal and pubic rami lesions. The majority of patients respond well to periods of enforced bed rest and administration of analgesics. Recognition of the spectrum of imaging findings for this entity should lead to its correct identification and the institution of appropriate treatment.

Induction of apoptosis by c-Fos protein

The role of c-Fos in apoptosis was examined in two Syrian hamster embryo cell lines (sup+I and sup-II) and a human colorectal carcinoma cell line (RKO), using the chimeric Fos-estrogen receptor fusion protein c-FosER. As previously reported, contrasting responses were observed when these two cell lines were placed under growth factor deprivation conditions; sup+I cells were highly susceptible to apoptosis, whereas sup-II cells were resistant. In this report, we show that the activated c-FosER protein induces apoptosis in sup-II preneoplastic cells in serum-free medium, indicating that c-Fos protein can induce apoptotic cell death in these cells. c-Fos-induced apoptosis was not blocked by the protein synthesis inhibitor cycloheximide, suggesting that the c-Fos transcriptional activation activity is not involved. This conclusion was further supported by the observation that overexpression of v-Fos, which is highly proficient in transcriptional activation but deficient in the transcriptional repression activity associated with c-Fos, did not induce apoptosis. Constitutively expressed Bcl-2 delayed the onset of low-serum-induced apoptosis in sup+I cells and enhanced survival in sup-II cells. Further, coexpression of Bcl-2 and c-FosER in sup+I or sup-II cells protected the cells from c-FosER-induced apoptosis. The possibility that c-FosER-induced apoptosis requires a p53 function was examined. Colorectal carcinoma RKOp53+/+ cells, which do not normally undergo apoptosis in serum-free medium, showed apoptotic DNA fragmentation upon expression and activation of c-FosER. Further, when the wild-type p53 protein was diminished in the RKO cells by infection with the papillomavirus E6 gene, subsequent c-FosER-induced apoptosis was blocked. The data suggest that c-Fos protein plays a causal role in the activation of apoptosis in a p53-dependent manner. This activity does not require new protein synthesis and is blocked by overexpression of Bcl-2 protein.

Cantor network, control algorithm, two-dimensional compact structure and its optical implementation

A compact integrating module technique for packaging a optical multistage Cantor network with a polarization multiplex technique is suggested. The modules have a unique configuration, which is the solid-state combination of a polarization rotator, double birefringent slabs, and a 2 × 2 switch array. The design and the fabrication of an eight-channel optical nonblocking Cantor network are demonstrated, and a fast-setup control algorithm is developed. The network systems are easy to assemble and insensitive to environment disturbance.

Lack of functional retinoblastoma protein mediates increased resistance to antimetabolites in human sarcoma cell lines

Growth inhibition assays indicated that the IC50 values for methotrexate (MTX) and 5-fluorodeoxyuridine (FdUrd) in HS-18, a liposarcoma cell line lacking retinoblastoma protein (pRB), and SaOS-2, an osteosarcoma cell line with a truncated and nonfunctional pRB, were 10- to 12-fold and 4- to 11-fold higher, respectively, than for the HT-1080 (fibrosarcoma) cell line, which has wild-type pRB. These Rb-/- cell lines exhibited a 2- to 4-fold increase in both dihydrofolate reductase (DHFR) and thymidylate synthase (TS) enzyme activities as well as a 3- to 4-fold increase in mRNA levels for these enzymes compared to the HT-1080 (Rb+/+) cells. This increase in expression was not due to amplification of the DHFR and TS genes. Growth inhibition by MTX and FdUrd was increased and DHFR and TS activities and expression were correspondingly decreased in Rb transfectants of SaOS-2 cells. In contrast, there was no significant difference in growth inhibition among these cell lines for the nonantimetabolites VP-16, cisplatin, and doxorubicin. A gel mobility-shift assay showed that parental SaOS-2 cells had increased levels of free E2F compared to the Rb-reconstituted SaOS-2 cells. These results indicate that pRB defective cells may have decreased sensitivity to growth inhibition by target enzymes encoded by genes whose transcription is enhanced by E2F proteins and suggest mechanisms of interaction between cytotoxic agents and genes involved in cell cycle progression.

Three-compartment wrist arthrography: direct comparison of digital subtraction with nonsubtraction images

PURPOSE

To determine the diagnostic value of digital subtraction and fluoroscopic spot images in wrist arthrography, alone and in combination.

MATERIALS AND METHODS

Randomized selective bilateral three-compartment wrist arthrography was performed in 64 patients. The fluoroscopic spot and digital subtraction images were read separately by two radiologists without knowledge of the clinical data.

RESULTS

One hundred twenty communicating defects were found in 69 wrists in 42 patients. Fluoroscopic spot radiographs alone depicted defects in all 69 wrists, but precise localization was not possible in 10 defects. Subtraction images alone demonstrated 59 defects. The defects not seen with digital subtraction imaging were identified after wrist motion. Digital subtraction images demonstrated defects earlier during the joint injection and demonstrated the exact site of the 10 defects not localized on the nonsubtracted images.

CONCLUSION

Digital subtraction and fluoroscopic spot images are complementary in wrist arthrography and, when used in combination, increase the ability to localize the sites of defects, although the value added by the subtraction technique is small.

Time-dependent phenomena in plasma-assisted chemical vapor deposition of rugate optical films

The plasma-assisted chemical vapor deposition technique was used to produce thin-film structures with both sinusoidally and stepwise varying refractive-index profiles. The refractive index of the SiO(x)N(y) system used in the fabrication was found to be time dependent following a stepwise change in reactant gas flows or initiation of the plasma. This time dependence has been quantified using in situ ellipsometry and was found to have components with exponential and linear dependences. The time dependence of water vapor partial pressure in the system was identified as the cause of the linear dependence. Allowance for the time-dependent effects has improved the agreement between the calculated spectral response and the measured result for a broadband high-reflectance mirror consisting of an arithmetic progression of discrete layers.

[Peripheral anterior synechiae overlying the haptics of posterior chamber lenses]

To study the changes of the anterior chamber angle after intraocular lens implantation, 111 patients (130 eyes) with posterior chamber intraocular lens implantation at different post-operative periods were examined by gonioscopy. Peripheral anterior synechia overlying the position of the lens haptic (lens haptic PAS) was observed in up to 50.8% of eyes implanted with haptics vaulted anteriorly by 10%. The lens haptic PAS is easy to be identified, it is a broad based forward displacement of the peripheral iris adhesive to the anterior wall of the anterior chamber angle. The size of the PAS was of half to one o'clock position and occasionally it was of one and a half to two o'clock position. The differences between the rates of occurrence of lens haptic PAS were not significant at different post-operative periods (P > 0.05). 55.9% of the sulcus fixated and 42.3% of the capsular fixated eyes had lens haptic PAS (P > 0.05). There were more lens haptic PAS in eyes with horizontally oriented lens haptics (62.7%) than with lens haptics at vertical position (41.4%, P < 0.05). Regular gonioscopy for posterior chamber lens implantation was recommended.

A 9-year-old girl with a bowed right forearm 6 months after a fracture

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopedic surgeon. Initial history, physical findings, and roentgenographic examinations are found on the first page. The final clinical and roentgenographic differential diagnoses are presented on the following pages.

Deficiency of retinoblastoma protein leads to inappropriate S-phase entry, activation of E2F-responsive genes, and apoptosis

The retinoblastoma susceptibility gene (Rb) participates in controlling the G1/S-phase transition, presumably by binding and inactivating E2F transcription activator family members. Mouse embryonic fibroblasts (MEFs) with no, one, or two inactivated Rb genes were used to determine the specific contributions of Rb protein to cell cycle progression and gene expression. MEFs lacking both Rb alleles (Rb-/-) entered S phase in the presence of the dihydrofolate reductase inhibitor methotrexate. Two E2F target genes, dihydrofolate reductase and thymidylate synthase, displayed elevated mRNA and protein levels in Rb- MEFs. Since absence of functional Rb protein in MEFs is sufficient for S-phase entry under growth-limiting conditions, these data indicate that the E2F complexes containing Rb protein, and not the Rb-related proteins p107 and p130, may be rate limiting for the G1/S transition. Antineoplastic drugs caused accumulation of p53 in the nuclei of both Rb+/+ and Rb-/- MEFs. While p53 induction led to apoptosis in Rb-/- MEFs, Rb+/- and Rb+/+ MEFs underwent cell cycle arrest without apoptosis. These results reveal that diverse growth signals work through Rb to regulate entry into S phase, and they indicate that absence of Rb protein produces a constitutive DNA replication signal capable of activating a p53-associated apoptotic response.

Structural analysis and comparison of the C-terminal transport signal domains of hemolysin A and leukotoxin A

NMR spectroscopy was used to study the structure of the C-terminal signal sequences of the bacterial toxins, hemolysin A(HlyA) and leukotoxin A (LktA). The two signals share little sequence homology; however, both can direct toxin transport with equal efficiency. We report here that in a membrane mimetic environment both peptides form two short non-interacting alpha-helices separated by a short loop. This higher order structure may be a common feature of C-terminal signals and may be required for interaction with the membrane associated transporter complex.

The regulatory regions of the rice tungro bacilliform virus promoter and interacting nuclear factors in rice (Oryza sativa L.)

The Rice Tungro Bacilliform Virus (RTBV) promoter confers phloem-specific gene expression in transgenic rice plants. A series of promoter deletion mutants were fused with the Escherichia coli beta-glucuronidase A (uidA) reporter gene and introduced into transgenic rice plants. The RTBV promoter confers substantially stronger expression in shoots than in roots. A fragment of the promoter comprising nucleotides -164 to +45 relative to the transcriptional start site contains sufficient information for phloem-specific gene expression. Within this region, nucleotides -164 to -43 were essential for promoter function since deletion of this fragment dramatically reduced promoter activity. Gel-retardation assays identified two groups of rice nuclear factors (RNFG1 and RNFG2) that bind to the -164 to +45 promoter fragment. Competition and DNasel footprinting experiments indicated that RNFG1 bound to nucleotides -3 to +8 (Box I) while RNFG2 bound to nucleotides -53 to -39 (Box II). Interactions between the two groups of factors were observed. In addition, we found differences in the binding of nuclear factors from shoots versus from roots, in agreement with the different activities of the promoter in these two organs. It is proposed that binding of RNFG1 and RNFG2 between nucleotides -164 to +45 is essential for the tissue-specific expression of this promoter.

Self-activation of N-phosphoamino acids and N-phosphodipeptides in oligopeptide formation

N-Phosphorylamino acids and N-phosphoryldipeptides can self-activate to give the oligopeptide. An intramolecular mixed anhydride intermediate might exist during the self-activating process. A peptide bond was formed from the N-terminus to the C-terminus by the '1 + n' mechanism, which was similar to the rRNA-peptide biosynthesis pathway.

Expression of chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase in Escherichia coli

Chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase was expressed in E. coli by using a pET3a T7 RNA polymerase-based expression system and was purified to homogeneity. The kinase and bisphosphatase of the expressed bifunctional enzyme had kinetic properties identical to those of the native chicken liver enzyme. However, the kinase activity of the chicken liver enzyme was 7-fold higher, while the bisphosphatase activity was 50 percent lower than those of the rat liver enzyme. Cys-256 of the rat liver bisphosphatase domain is not conserved in the chicken liver enzyme. A site-directed mutation was engineered at Cys-256 of the rat liver enzyme and the results indicate that the variation of this residue is not responsible for the difference in fructose-2,6-bisphosphatase activity between the rat and chicken liver enzymes. It is postulated that the difference in the kinase/bisphosphatase activity ratios of these two enzymes results from differences in their NH2-terminal regions.

Secretion and circular dichroism analysis of the C-terminal signal peptides of HlyA and LktA

The secretion of the 107 kDa hemolysin A (HlyA) from Escherichia coli is mediated by membrane proteins hemolysin B (HlyB) and hemolysin D (HlyD). The signal for transport has been mapped to the C-terminal 60 amino acids of the HylA molecule. We have shown previously that the C-terminal 70 amino acids of leukotoxin (LktA) from Pasteurella hemolytica can substitute functionally for the HlyA signal sequence. This 70 amino acid peptide contains little primary sequence similarity to the HlyA signal sequence, and we have hypothesized that these signal sequences assume a similar higher-order structure which is recognized by the HlyB/D transporter. In the present study, we have expressed and purified small peptides containing the C-terminal 61 amino acids of HlyA and the C-terminal 70 amino acids of LktA. We show that these signal peptides are sufficient for secretion from E. coli in a HlyB/D dependent manner. Circular dichroism analyses show that both molecules exhibit common biophysical properties. In aqueous solution, they appear to be mainly unstructured, but in a membrane mimetic environment they assume a helical secondary structure. The conformational change observed for both peptides going from an aqueous to a membrane mimetic environment may be an important feature of these signal sequences necessary for their recognition and transport.

Mutations in rpoB gene of rifampicin resistant clinical isolates of Mycobacterium tuberculosis in Japan

In Mycobacterium tuberculosis, involvement of alterations of the RNA polymerase beta subunit in resistance to rifampicin has been described by Telenti et al. To determine if the same correlation could be observed between the mutation of the rpoB gene and clinically isolated M. tuberculosis of the rifampicin-resistant phenotype in Japan, 47 strains of M. tuberculosis of the rifampicin-resistant phenotype, 17 of the rifampicin-susceptible phenotype, and 4 type strains were examined. A 411-base pair (bp) rpoB fragment was amplified by the polymerase chain reaction and subjected to solid phase direct sequencing. By comparing the nucleotides, mutation involving 8 conserved amino acids were identified in 44 of the 47 (93.6%) rifampicin-resistant isolates, but in none of the 17 sensitive isolates and 4 type strains. All mutations found were clustered within a region of 23 amino acids. Thus, similar to the results reported by Telenti et al., substitution of a limited number of highly conserved amino acids encoded by the rpoB gene appears to be the molecular mechanism responsible for resistance to rifampicin in Japanese clinical isolates of M. tuberculosis. Our results suggest that direct DNA sequencing of the rpoB gene may be a reliable method for identifying rifampicin-resistant M. tuberculosis strains among Japanese clinical isolates.

Modified direct twos-complement parallel array multiplication algorithm for complex matrix operation

A direct twos-complement parallel array multiplication algorithm is introduced and modified for digital optical numerical computation. The modified version overcomes the problems encountered in the conventional optical twos-complement algorithm. In the array, all the summands are generated in parallel, and the relevant summands having the same weights are added simultaneously without carries, resulting in the product expressed in a mixed twos-complement system. In a two-stage array, complex multiplication is possible with using four real subarrays. Furthermore, with a three-stage array architecture, complex matrix operation is straightforwardly accomplished. In the experiment, parallel two-stage array complex multiplication with liquid-crystal panels is demonstrated.

Colonic protein fermentation and promotion of colon carcinogenesis by thermolyzed casein

Thermolyzed casein is known to promote the growth of aberrant crypt foci (ACF) and colon cancer when it is fed to rats that have been initiated with azoxymethane. We speculated that the promotion was a consequence of increased colonic protein fermentation (i.e., that the thermolysis of the casein decreases its digestibility, increases the amount of protein reaching the colon, and increases colonic protein fermentation and that the potentially toxic products of this fermentation promote colon carcinogenesis). We found that the thermolysis of casein reduces its digestibility and increases colonic protein fermentation, as assessed by fecal ammonium and urinary phenol, cresol, and indol-3-ol. Thermolysis of two other proteins, soy and egg white protein, also increases colonic protein fermentation with increased fecal ammonia and urinary phenols, and thermolysis of all three proteins increases the levels of ammonia and butyric, valeric, and i-valeric acids in the cecal contents. We found, however, that the increased protein fermentation observed with thermolysis is not associated with promotion of colon carcinogenesis. With casein, the kinetics of protein fermentation with increasing thermolysis time are clearly different from the kinetics of promotion of ACF growth. The formation of the fermentation products was highest when the protein was thermolyzed for one hour, whereas promotion was highest for protein that had been thermolyzed for two or more hours. With soy and egg white, thermolysis increased colonic protein fermentation but did not promote colon carcinogenesis. Thus, although thermolysis of dietary casein increases colonic protein fermentation, products of this fermentation do not appear to be responsible for the promotion of colon carcinogenesis. Indeed, the results suggest that protein fermentation products do not play an important role in colon cancer promotion.

Giant-cell tumor of the distal phalanx of the hand in a child

Giant-cell tumor of bone in the distal phalanx is rare, as is its clinical occurrence in children. A case of a 10-year-old girl with giant-cell tumor in the distal phalanx of the left thumb is reported, and a literature review of phalangeal giant-cell tumor of the hand is presented. The tumor was curetted, and after 2.5 years there was no recurrence.

Ionic mechanism of acupuncture on improvement of learning and memory in aged mammals

Memory impairment is one of the most frustrating problems for older people. Several acupoints were used for the treatment of memory loss in old rats, and the elemental mechanism of acupuncture therapy was studied with Inductively Coupled Plasma Spectroscopy. The result indicates that acupuncture improves learning and memory ability significantly in aged animals when compared with controls. This study demonstrated that elevations of eight essential elements (B, Ca, Cu, Fe, K, Mg, Na, and P) in the brain are the ionic basis for the therapeutic effect of acupuncture. A hypothetical model of the mechanism of acupuncture therapy is described.

An autonomously propagating luciferase-encoding vector for Dictyostelium discoideum

We have constructed a luc reporter vector for Dictyostelium discoideum using a 626-bp fragment from the nuclear-associated plasmid Ddp2. The ori from Ddp2 is localized within this fragment and was used to provide an autonomous replication sequence for the reporter vector. This reporter vector was stably retained in D. discoideum AX3K cells without alteration. The vector molecule was also found to exist in relatively low copy number compared to other Dictyostelium vectors in the transformed cells. We demonstrated the utility of this vector as a reporter vector with glycogen synthase promoter/luc fusions of varying sizes.

Solution structure of the tetrameric minimum transforming domain of p53

We report the solution structure of the minimum transforming domain (residues 303-366) of human p53 (p53tet) determined by multidimensional NMR spectroscopy. This domain contains a number of important functions associated with p53 activity including transformation, oligomerization, nuclear localization and a phosphorylation site for p34/cdc2 kinase. p53tet forms a symmetric dimer of dimers that is significantly different from a recent structure reported for a shorter construct of this domain. Phosphorylation of Ser 315 has only minor structural consequences, as this region of the protein is unstructured. Modelling based on the p53tet structure suggests possible modes of interaction between adjacent domains in full-length p53 as well as modes of interaction with DNA.

Optical complex matrix-vector multiplication with negative binary inner products

Based on the mixed negative binary number system, we propose an inner-product algorithm for digital complex-valued matrix-vector multiplication. The features are no carries, no signs, no indications for decimal points, and simple preprocessing and postprocessing. Correspondingly, an optical architecture of incoherent optical correlation with spatial digital coding of data is suggested. Negative binary complex matrix-vector multiplication can be realized optically in parallel with a high accuracy. The experimental result is also given.