Large-scale discovery of novel genetic causes of developmental disorders

Despite three decades of successful, predominantly phenotype-driven discovery of the genetic causes of monogenic disorders, up to half of children with severe developmental disorders of probable genetic origin remain without a genetic diagnosis. Particularly challenging are those disorders rare enough to have eluded recognition as a discrete clinical entity, those with highly variable clinical manifestations, and those that are difficult to distinguish from other, very similar, disorders. Here we demonstrate the power of using an unbiased genotype-driven approach to identify subsets of patients with similar disorders. By studying 1,133 children with severe, undiagnosed developmental disorders, and their parents, using a combination of exome sequencing and array-based detection of chromosomal rearrangements, we discovered 12 novel genes associated with developmental disorders. These newly implicated genes increase by 10% (from 28% to 31%) the proportion of children that could be diagnosed. Clustering of missense mutations in six of these newly implicated genes suggests that normal development is being perturbed by an activating or dominant-negative mechanism. Our findings demonstrate the value of adopting a comprehensive strategy, both genome-wide and nationwide, to elucidate the underlying causes of rare genetic disorders.

Selection of mutations in the hepatitis B virus polymerase during therapy of transplant recipients with lamivudine

We describe mutations in the hepatitis B virus (HBV) polymerase gene in viruses which reactivated in two patients during therapy with -2'-deoxy-3'-thiacytidine, or lamivudine (3TC), and following orthotopic liver transplantation for chronic hepatitis B. Virus resistance to 3TC is associated with mutations which lead to amino acid substitutions in the highly conserved tyr-met-asp-asp (YMDD) motif, part of the active site of the polymerase, and which parallel those seen in resistant human immunodeficiency virus (HIV). Substitutions of valine and isoleucine for methionine were found in the two cases. The significance of single secondary mutations, which differ between viruses from the two patients, remains to be determined. Thus, viral resistance to lamivudine of hepatitis B virus mimics that of HIV and can occur in the setting of immunosuppression after liver transplantations.

Lamivudine prophylaxis against reinfection in liver transplantation for hepatitis B cirrhosis

BACKGROUND

Orthotopic liver transplantation in patients positive for hepatitis B virus (HBV) DNA is associated with a high reinfection rate, even with hepatitis B immunoglobulin (HBIG) prophylaxis. Nucleoside analogues that inhibit hepatitis B replication in patients with chronic hepatitis B could prevent reinfection after transplantation. The aim of this study was to analyse the efficacy and safety of prophylaxis both before and after transplantation with the nucleoside analogue lamivudine, without HBIG, in patients undergoing liver transplantation.

METHODS

17 HBsAg-positive patients with decompensated cirrhosis and previous evidence of viral replication were enrolled. 12 were HBV-DNA-positive by a signal amplification assay. Patients were treated with oral lamivudine (100 mg daily) for at least 4 weeks before transplantation and followed up for 18-90 weeks after transplantation.

FINDINGS

HBV DNA became undetectable in serum before transplantation in all HBV-DNA-positive patients. Four died before transplantation from complications of cirrhosis; one patient was withdrawn from the study because of a cerebrovascular accident. The remaining 12 patients underwent transplantation. Two patients died after transplantation (one at 3 days and one [suicide] at 20 weeks). HBV DNA reappeared in one patient with histological evidence of recurrent hepatitis (72 weeks). By week 24 the nine remaining patients had lost HBsAg and remained negative for HBV DNA.

INTERPRETATION

Lamivudine treatment may prove useful in preventing recurrence of hepatitis B after liver transplantation. The effect on survival of patients after transplantation remains to be assessed.

Internal olefins to linear amines

The selective synthesis of linear amines from internal olefins or olefin mixtures was achieved through a catalytic one-pot reaction consisting of an initial olefin isomerization followed by hydroformylation and reductive amination. Key to the success is the use of specially designed phosphine ligands in the presence of rhodium catalysts. This reaction constitutes an economically attractive and environmentally favorable synthesis of linear aliphatic amines.

Degradation of polychlorinated biphenyls by two species of Achromobacter

Two species of Achromobacter were isolated from sewage effluent using biphenyl (BP) and p-chlorobiphenyl (pCB) respectively as sole carbon sources. Achromobacter BP grown on biphenyl accumulated a product with an ultraviolet absorption maximum at 257 nm which could not be identified. Washed cell suspensions of both isolates oxidized biphenyl, o-phenylphenol, phenylpyruvate, catechol, p-chlorobiphenyl, m-chlorobiphenyl, o-chlorobiphenyl, o,o′-dichlorobiphenyl, and p,p′-dichlorobiphenyl. Both isolates produced meta cleavage products by fission of the benzene ring. However, spectral characteristics of degradation products from respective substrates were different between the two isolates, indicating divergent degradation pathways. Benzoic and p-chlorobenzoic acids were produced from the degradation of BP and pCB, respectively, by Achromobacter pCB. Chloride was not produced by either isolate during the degradation of all chlorobiphenyls tested including the growth of Achromobacter pCB on p-chlorobiphenyl.

Radio-frequency thermal ablation with NaCl solution injection: effect of electrical conductivity on tissue heating and coagulation-phantom and porcine liver study

PURPOSE

To characterize the effects of NaCl concentration on tissue electrical conductivity, radio-frequency (RF) deposition, and heating in phantoms and optimize adjunctive NaCl solution injection for RF ablation in an in vivo model.

MATERIALS AND METHODS

RF was applied for 12-15 minutes with internally cooled electrodes. For phantom experiments (n = 51), the NaCl concentration in standardized 5% agar was varied (0%-25.0%). A nonlinear simplex optimization strategy was then used in normal porcine liver (n = 44) to determine optimal pre-RF NaCl solution injection parameters (concentration, 0%-38.5%; volume, 0-25 mL). NaCl concentration and tissue conductivity were correlated with RF energy deposition, tissue heating, and induced coagulation.

RESULTS

NaCl concentration had significant but nonlinear effects on electrical conductivity, RF deposition, and heating of agar phantoms (P<.01). Progressively greater heating was observed to 5.0% NaCl, with reduced temperatures at higher concentrations. For in vivo liver, NaCl solution volume and concentration significantly influenced both tissue heating and coagulation (P<.001). Maximum heating 20 mm from the electrode (102.9 degrees C +/- 4.3 [SD]) and coagulation (7.1 cm +/- 1.1) occurred with injection of 6 mL of 38.5% (saturated) NaCl solution.

CONCLUSION

Injection of NaCl solution before RF ablation can increase energy deposition, tissue heating, and induced coagulation, which will likely benefit clinical RF ablation. In normal well-perfused liver, maximum coagulation (7.0 cm) occurs with injection of small volumes of saturated NaCl solution.

UK Consensus on Normal Tissue Dose Constraints for Stereotactic Radiotherapy

Six UK studies investigating stereotactic ablative radiotherapy (SABR) are currently open. Many of these involve the treatment of oligometastatic disease at different locations in the body. Members of all the trial management groups collaborated to generate a consensus document on appropriate organ at risk dose constraints. Values from existing but older reviews were updated using data from current studies. It is hoped that this unified approach will facilitate standardised implementation of SABR across the UK and will allow meaningful toxicity comparisons between SABR studies and internationally.

Preconditioning of human myocardium with adenosine during coronary angioplasty

BACKGROUND

It is unknown whether adenosine can precondition human myocardium against ischemia in vivo.

METHODS AND RESULTS

Thirty patients were randomized to receive a 10-minute intracoronary infusion of adenosine (2 mg/min) or normal saline; 10 minutes later, they underwent percutaneous transluminal coronary angioplasty (PTCA; three 2-minute balloon inflations 5 minutes apart). In control patients, the ST-segment shift on the intracoronary ECG was significantly greater during the first inflation than during the second and third inflations, consistent with ischemic preconditioning. In contrast, in adenosine-treated patients, there were no differences in ST-segment shift during the three inflations. The ST-segment shift was significantly smaller in the adenosine-treated group compared with the control group during all three inflations. The reduction in ST-segment shift afforded by adenosine during the first inflation (-72% versus first inflation in control subjects) was greater than that afforded by ischemic preconditioning in control subjects (-52% during the third versus first inflation). Measurements of chest pain score paralleled those of ST-segment shift. Adenosine had no effect on baseline regional wall motion as determined by quantitative two-dimensional echocardiography. Thus, intracoronary infusion of adenosine before PTCA rendered the myocardium remarkably resistant to subsequent ischemia. Judging from the intracoronary ECG, the protection provided by adenosine was even superior to that provided in control subjects by the ischemia associated with the first two balloon inflations. Infusion of adenosine had no major adverse effects in patients undergoing PTCA of the left anterior descending or circumflex arteries.

CONCLUSIONS

Adenosine preconditions human myocardium against ischemia in vivo. Pretreatment with adenosine is remarkably effective (even more effective than ischemic preconditioning) and could be used prophylactically to attenuate ischemia in selected patients undergoing PTCA of the left anterior descending coronary artery. Whether adenosine can be safely infused into the right or the circumflex coronary artery in the presence of a temporary pacemaker remains to be established.

ATM and breast cancer susceptibility

ATM was originally identified by positional cloning as the gene that underlies the autosomal recessive condition ataxia-telangiectasia. The encoded protein plays a central role in the complex processes that repair DNA double-strand breaks. Nearly 20 years ago, epidemiological surveys of relatives of ataxia-telangiectasia cases suggested that female relatives were at modestly increased risk of breast cancer. Subsequently, many studies have tried to clarify the role of ATM in breast cancer susceptibility, but have produced inconclusive and/or inconsistent results. Recently, large epidemiological and molecular studies have finally provided conclusive evidence that ATM mutations that cause ataxia-telangiectasia are breast cancer susceptibility alleles.

Two highly similar multidrug transporters of Bacillus subtilis whose expression is differentially regulated

The Bacillus subtilis genome encodes two multidrug efflux transporters sharing 51% sequence identity: Bmr, described previously, and Blt, described here. Overexpression of either transporter in B. subtilis leads to a similar increase in resistance to ethidium bromide, rhodamine and acridine dyes, tetraphenylphosphonium, doxorubicin, and fluoroquinolone antibiotics. However, Blt differs widely from Bmr in its expression pattern. Under standard cultivation conditions, B. subtilis expresses Bmr but Blt expression is undetectable. We have previously shown that Bmr expression is regulated by BmrR, a member of the family of MerR-like transcriptional activators. Here we show that blt transcription is regulated by another member of the same family, BltR. The DNA-binding domains of BmrR and BltR are related, but their putative inducer-binding domains are dissimilar, suggesting that Bmr and Blt are expressed in response to different inducers. Indeed, rhodamine, a substrate of Bmr and Blt and a known inducer of Bmr expression, does not induce Blt expression. Blt expression has been observed only in B. subtilis, carrying mutation acfA, which, as we show here, alters the sequence of the blt gene promoter. Unlike bmr, which is transcribed as a monocistronic mRNA, blt is cotranscribed with a downstream gene encoding a putative acetyltransferase. Overall, the differences in transcriptional control and operon organization between bmr and blt suggest that the transporters encoded by these genes have independent functions involving the transport of distinct physiological compounds.

Lamivudine without HBIg for prevention of graft reinfection by hepatitis B: long-term follow-up

BACKGROUND

This open, multicenter study was conducted to evaluate the efficacy and safety of lamivudine prophylaxis given to chronic hepatitis B virus-(HBV) infected patients before and after orthotopic liver transplantation (OLT). We now present long-term data that follow our previous short-term report.

METHODS

Twenty-three patients were treated with lamivudine (100 mg orally, daily); 13 (57%), were serum HBV DNA positive (Abbott Genostics, Abbott Laboratories, Chicago, IL) at study entry. Patients received lamivudine for at least 4 weeks before OLT, and for up to 50 months (median 25 months) after OLT.

RESULTS

Of the 23 treated patients, 17 survived to undergo OLT. Eleven patients (65%) survived up to 4 years (median 36 months) after OLT. One of the survivors stopped lamivudine because of a possible adverse reaction 9 months post-OLT, and prophylaxis with HBV immune globulin was then established. Ten survivors continue lamivudine. Eight long-term survivors have normal liver function without evidence of HBV reinfection. Of the 17 transplanted patients, 6 died. Four patients died (3 days to 5 months post-OLT) without evidence of graft reinfection. Two further patients died at 19 and 23 months post-OLT from graft failure. Both patients had YMDD variant detected at 12 months post-OLT. Two other patients with YMDD-variant HBV remain alive on lamivudine, 9 and 15 months after development of the variant.

CONCLUSIONS

Lamivudine, given before and after OLT, prevents significant graft reinfection for the majority of treated patients. The study has also shown that lamivudine is extremely well tolerated by liver failure patients and for a prolonged period after transplantation.

Cross-talk between NFkB and the PI3-kinase/AKT pathway can be targeted in primary effusion lymphoma (PEL) cell lines for efficient apoptosis

Background

A number of constitutively activated signaling pathways play critical roles in the survival and growth of primary effusion lymphoma cells (PELs) including NFkB and PI3/AKT kinase cascades. NFkBis constitutively activated in a number of malignancies, including multiple myeloma, Burkitt’s lymphoma and diffuse large cell B-cell lymphoma. However, its role in primary effusion lymphoma has not been fully explored.

Methodology/Principal Findings

We used pharmacological inhibition and gene silencing to define the role of NFkB in growth and survival of PEL cells. Inhibition of NFkB activity by Bay11-7085 resulted in decreased expression of p65 in the nuclear compartment as detected by EMSA assays. In addition, Bay11-7085 treatment caused de-phosphorylation of AKT and its downstream targets suggesting a cross-talk between NFkB and the PI3-kinase/AKT pathway. Importantly, treatment of PEL cells with Bay11-7085 led to inhibition of cell viability and induced apoptosis in a dose dependent manner. Similar apoptotic effects were found when p65 was knocked down using specific small interference RNA. Finally, co-treatment of PEL cells with suboptimal doses of Bay11-7085 and LY294002 led to synergistic apoptotic responses in PEL cells.

Conclusion/Significance

These data support a strong biological-link between NFkB and the PI3-kinase/AKT pathway in the modulation of anti-apoptotic effects in PEL cells. Synergistic targeting of these pathways using NFKB- and PI3-kinase/AKT- inhibitors may have a therapeutic potential for the treatment of PEL and possibly other malignancies with constitutive activation of these pathways.

High pre-treatment serum hepatitis B virus titre predicts failure of lamivudine prophylaxis and graft re-infection after liver transplantation

BACKGROUND/AIMS

Orthotopic liver transplantation has an established role for the treatment of patients with chronic liver failure secondary to hepatitis B virus (HBV) infection. Unfortunately, recurrent infection of the graft can be associated with aggressive disease, and with diminished graft and patient survival. Currently, the role of nucleoside analogues for prevention of graft re-infection is being evaluated. Preliminary results are encouraging, but treatment failure has been associated with emergence of drug-resistant virus.

METHODS

We have studied ten consecutive patients who received lamivudine prophylaxis for prevention of HBV graft reinfection. Sequential sera, collected prelamivudine then during treatment before and after liver transplantation, were examined. Conventional serological markers were measured, as were serum viral DNA levels with a sensitive quantitative polymerase chain reaction assay.

RESULTS

Lamivudine treatment effected a reduction in serum HBV levels, but six patients still had measurable viral DNA at the time of transplantation. Five patients developed graft re-infection with lamivudine-resistant virus. Resistant virus emerged 8 to 15 months post-transplant. The likelihood of emergence of resistant virus was related to the pre-treatment serum HBV titre. Persistent serum viral DNA positivity and evidence of graft re-infection during the early post-transplant period did not predict the subsequent emergence of resistant virus.

CONCLUSIONS

Our observations suggest that the resistant species may be present in the viral quasispecies in the serum and liver of patients with high-level replication prior to lamivudine exposure. The resistant species can persist during lamivudine treatment prior to transplantation, and emerge following transplantation. These observations suggest strategies which might prevent the emergence of drug-resistant species, and imply that graft re-infection may be a preventable phenomenon.

Genome-wide expression analysis of Middle Eastern colorectal cancer reveals FOXM1 as a novel target for cancer therapy

To identify genes potentially playing an important role in the progression of colorectal carcinoma (CRC), we screened global gene expression using cDNA expression array on 41 CRC tissue samples and 25 noncancerous colorectal tissue samples. Among the up-regulated genes, forkhead box M1 (FOXM1) has been shown to play a critical role in pathogenesis of various malignancies. Using immunohistochemistry on 448 Saudi CRC samples in tissue microarray format, FoxM1 protein overexpression was seen in 66% of CRC tissues and was significantly associated with poorly differentiated and highly proliferative tumors (P = 0.0200 and 0.0018, respectively). FoxM1 expression was also significantly associated with MMP-9 protein expression (P = 0.0002). In vitro data using CRC cell lines showed that inhibition of FoxM1 by thiostrepton resulted in inhibition of proliferation and induction of apoptosis in a dose-dependent manner. Overexpression of FoxM1 potentiated cell proliferation, cell transformation, and migration/invasion of CRC cells via up-regulation of FoxM1 target genes MMP2 and MMP9 and protected these cells from thiostrepton-mediated antiproliferative effects. Finally, in vivo, overexpression of FoxM1 promoted growth of CRC-cell line xenograft tumors in nude mice. Altogether, our data indicate that FoxM1 signaling contributes to aggressiveness in a subset of CRC and that the FOXM1 gene may serve as a useful molecular biomarker and potential therapeutic target.

Isolation from human calcium oxalate renal stones of nephrocalcin, a glycoprotein inhibitor of calcium oxalate crystal growth. Evidence that nephrocalcin from patients with calcium oxalate nephrolithiasis is deficient in gamma-carboxyglutamic acid

We have determined that the organic matrix of calcium oxalate kidney stones contains a glycoprotein inhibitor of calcium oxalate crystal growth (nephrocalcin) that resembles nephrocalcin present in the urine of patients with calcium oxalate stones and differs from nephrocalcin from the urine of normal people. Pulverized calcium oxalate renal stones were extracted with 0.05 M EDTA, pH 8.0; nephrocalcin eluted in five peaks using DEAE-cellulose column chromatography, and each peak was further resolved by Sephacryl S-200 column chromatography. Four of the five DEAE peaks corresponded to those usually found in nephrocalcin from urine; the fifth eluted at a lower ionic strength than any found in urine. Amino acid compositions and surface properties of nephrocalcins isolated from kidney stones closely resembled those of nephrocalcins isolated from urine of stone-forming patients: they differed from normal in lacking gamma-carboxyglutamic acid residues, and in forming air-water interfacial films that were less stable than those formed by nephrocalcin from normal urine.

Neuropeptide Y, tyrosine hydroxylase and vasoactive intestinal polypeptide-immunoreactive nerve fibers in the vertebral bodies, discs, dura mater, and spinal ligaments of the rat lumbar spine

The occurrence of autonomic nerves in the lumbar spine of rats was investigated by immunohistochemical technique. Both peptidergic nerves, represented by immunoreactivity to neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), and noradrenergic nerves as reflected by tyrosine hydroxylase (TH) immunoreactivity, were identified. NPY- and TH-positive nerves were predominantly found in the blood vessels walls. They occurred in the bone and periosteum of the vertebral body, disc, dura mater, and in the spinal ligaments. They were particularly numerous along the growth plate and in the outer layers of the intervertebral discs. VIP-positive fibers were predominantly nonvascular. They occurred in all tissues analyzed, but were most abundant in the vertebral bone marrow and periosteum. The VIP-immunoreactive fibers in the outer fibrous layers of the disc and the spinal ligaments were occasionally observed in blood vessel walls. No immunoreactivity could be detected in the nucleus pulposus. In the dura mater, NPY-, TH- and VIP-positive fibers were found both in the ventral and dorsal portion. In view of the vasoconstrictive properties of both NPY and noradrenaline, it may be assumed that the abundance of NPY- and TH-immunoreactive nerves fibers in blood vessel walls reflects a vasoregulatory activity. The predominance of nonvascular VIP-positive fibers in the vertebral bone marrow and periosteum may represent an involvement in local bone physiology.

Plasma glucose and insulin profiles in normal subjects ingesting diets of varying carbohydrate, fat, and protein content

The 12-hr profiles of plasma glucose and insulin concentrations in 26 normal subjects ingesting a diet high in carbohydrate, protein, or fat have been determined. The diets were isocaloric and were given as three identical meals 4 hrs apart. In males the high carbohydrate diet resulted in glucose profiles similar to those obtained with the standard diet. In females the peak glucose concentration also was not increased but the glucose concentration remained elevated longer after each meal. In both groups the insulin curves followed the glucose curves. The post-meal glucose and insulin areas were significantly increased in the female group. The high protein diet resulted in only a small post-meal glucose rise particularly later in the day in both males and females. However, there was a sharp rise in insulin concentration after each meal. The total insulin area after each meal was nearly as great as with the standard diet. The high fat diet, which contained approximately the same carbohydrate content as the high protein diet, induced a clear increase in glucose concentration after each meal in the female group. However, the peak was progressively delayed with each meal. The insulin curves followed the glucose curves. In males a small, prolonged post-meal increase in glucose was observed after each meal. The insulin concentration increased modestly after the first meal and then remained elevated and changed little after the subsequent meals. These data help to define the glucose and insulin responses to meals varying greatly in protein, carbohydrate, and fat content and further indicate the need to consider the response of males and females separately.

Effects of nasal O2 on sleep-related disordered breathing in ambulatory patients with stable heart failure

OBJECTIVE

The purpose of this study was 1) to determine the effects of nasal O2 on periodic breathing, arterial oxyhemoglobin desaturation and nocturnal ventricular arrhythmias in patients with heart failure and 2) determine the characteristics of patients whose periodic breathing will be reversed by O2 administration; our hypothesis was that patients with more severe periodic breathing and desaturation, will respond more favorably to oxygen.

DESIGN

Prospective study.

SETTING

Referral sleep laboratory of a Department of Veterans Affairs Medical Center.

PARTICIPANTS

36 ambulatory male patients with heart failure whose initial polysomnograms showed periodic breathing with fifteen or more episodes of apnea (A) and hypopnea (H) per hour (AH index, AHI) were treated with nasal O2 during the subsequent full night polysomnography.

INTERVENTIONS

Oxygen.

MEASUREMENTS AND RESULTS

Arterial blood gases and hydrogen ion concentrations were measured, and cardiac radionuclide ventriculography, Holter monitoring, and polysomnography were done. The studies were scored blindly. Treatment with O2 resulted in a significant reduction in AHI (49+/-19 vs 29+/-29, means+/-SD), central apnea index (28+/-23 vs 13+/-18 per hour), and the percent of total sleep time below an arterial oxyhemoglobin saturation of 90% (23+/-21% vs 0.8+/-2.3%). In spite of virtual normalization of saturation with O2 therapy, the number of ventricular arrhythmias during sleep did not change significantly. In 39% of the patients (14 out of 36), O2 therapy resulted in reversal of central sleep apnea (defined by a reduction in AHI to less than 15/hr). In this group, the AHI decreased by 78% which was significantly (p=0.0001) more than improved (22%) in AHI of the remaining patients (n=22). The main differences between baseline characteristics of the two groups was a significantly higher mean PaCO2 in patients who did respond fully to O2 (39.3+/-5.4 vs 36.1+/-4.2 mm Hg, p=0.03). In both groups, however, O2 administration resulted in significant and similar improvement in arterial oxyhemoglobin saturation (saturation <90%, percent total sleep time 0.1+/-0.3% vs 1+/-3%).

CONCLUSION

In patients with stable heart failure, administration of nasal O2 significantly improves periodic breathing and virtually eliminates clinically significant arterial oxyhemoglobin desaturation. The beneficial effects of O2, however, may be modulated by the level of arterial PCO2. Acute O2 therapy has important benefits on sleep apnea and nocturnal arterial oxyhemoglobin desaturation in heart failure patients. Long term benefits of O2 therapy in heart failure and sleep apnea need to be determined.

Molecular analysis of the high-hemoglobin-F phenotype in Saudi Arabian sickle cell anemia

Patients from the eastern province of Saudi Arabia who have sickle cell anemia have high circulating levels of fetal hemoglobin (hemoglobin F, 17 percent), and they therefore have a mild form of the disease. To examine the molecular basis of the elevated production of hemoglobin F, we searched for mutations in the promoter regions of the two hemoglobin F gamma-globin genes (G gamma and A gamma). The DNA sequences 450 bp (base pairs) upstream of both the G gamma and A gamma globin genes were normal except for a single-base cytosine-to-thymidine (C----T) substitution at -158 bp 5' to the cap (preinitiation) site of the G gamma-globin gene of the high-hemoglobin-F chromosome. We searched for an association between this -158 C----T substitution and the production of hemoglobin F and G gamma in normal Saudis and Saudis with sickle cell disease or trait. The substitution was present in nearly 100 percent of the patients with sickle cell disease or trait, and in 22 percent of the normal Saudis. Homozygosity for this mutation had no demonstrable effect on hemoglobin F production in the normal Saudi population. We conclude that this mutation is not uniquely responsible for the increase in hemoglobin F in Saudi patients. It may nevertheless have an important role in regulating hemoglobin F production, but its expression is complex and requires interaction with additional factors, such as hemolytic stress or other molecular determinants, possibly linked to the sickle cell gene.

Effect of vesicular stomatitis virus matrix protein on transcription directed by host RNA polymerases I, II, and III

The matrix (M) protein of vesicular stomatitis virus (VSV) functions in virus assembly and inhibits host-directed gene expression independently of other viral components. Experiments in this study were carried out to determine the ability of M protein to inhibit transcription directed by each of the three host RNA polymerases (RNA polymerase I [RNAPI], RNAPII, and RNAPIII). The effects of wild-type (wt) VSV, v6 (a VSV mutant isolated from persistently infected cells), and tsO82 viruses on poly(A)+ and poly(A)- RNA synthesis were measured by incorporation of [3H]uridine. v6 and tsO82 viruses, which contain M-gene mutations, had a decreased ability to inhibit synthesis of both poly(A)+ and poly(A)- RNA. Nuclear runoff analysis showed that VSV inhibited transcription of 18S rRNA and alpha-tubulin genes, which was dependent on RNAPI and RNAPII, respectively, but infection with wt virus enhanced transcription of 5S rRNA by RNAPIII. The effect of M protein alone on transcription by RNAPI-, RNAPII-, and RNAPIII-dependent promoters was measured by cotransfection assays. M protein inhibited transcription from RNAPI- and RNAPII-dependent promoters in the absence of other viral gene products. RNAPIII-dependent transcription of the adenovirus VA promoters was also inhibited by M protein. However, as observed during wt VSV infection, M protein enhanced endogenous 5S rRNA transcription, indicating that the inhibition of transcription by RNAPIII was dependent on the nature of the promoter.

gli, a zinc finger transcription factor and oncogene, is expressed during normal mouse development

The oncogene GLI is amplified and expressed in some cases of human malignant glioma and undifferentiated childhood sarcoma and is the prototype for a gene family characterized by a highly conserved set of five tandem zinc fingers and a consensus cysteine-histidine link. This zinc finger motif has been shown to bind DNA with sequence specificity and may mediate transcriptional regulation. Since GLI is expressed in embryonal carcinoma cell lines but not in most normal adult tissues and shows significant sequence similarity within its zinc finger domain to cubitus interruptus dominant (ciD), a Drosophila segmentation gene known to be important in the morphogenesis of the posterior portion of each larval segment, we established the temporal and tissue expression patterns of the mouse homologue of human GLI in day 10 through 18 mouse embryos with Northern blotting, reverse transcriptase coupled PCR, and in situ hybridization. gli transcripts were demonstrated on days 10 through 18 of mouse embryonic development as well as in normal adult uterus, brain, testis, and limb. Tissue expression of gli during gestation was demonstrated in Meckel's precartilage mesenchyme, the basis occipitus, rib mesenchymal condensations, primordial vertebral bodies, digital mesenchymal condensations in forefoot and hindfoot plates, the ependymal layer of the spinal cord, and the mesoderm of the gastrointestinal tract. Expression persisted throughout gestation in developing bone and cartilage of the extremities, the ribs, and the vertebral bodies, as well as the gastrointestinal tract mesoderm. These findings support a role for gli family genes in normal craniofacial and digital development in mammals first suggested by the demonstration of translocation breakpoints within the GLI3 gene in families with the Greig cephalopolysyndactylyl syndrome and subsequently by reduced gli3 expression in the mouse mutant extra toes. It is surprising that a single gene would be expressed in such a wide range of mesenchymal structures.

Transurethral microwave thermotherapy (Prostatron version 2.5) compared with transurethral resection of the prostate for the treatment of benign prostatic hyperplasia: a randomized, controlled, parallel study

OBJECTIVE

To compare transurethral microwave thermotherapy (TUMT) with urethral cooling in a high-energy protocol (Prostatron version 2.5), with transurethral resection of the prostate (TURP) for the treatment of symptomatic, uncomplicated, urodynamically obstructive benign prostatic hyperplasia (BPH).

PATIENTS AND METHODS

Patients with moderate to severe symptomatic, uncomplicated BPH, unequivocally obstructed as assessed from the Abrams-Griffith nomogram, who were technically suitable for either form of treatment, were randomized into two groups of 30 patients each to undergo either TUMT or TURP. Five efficacy variables, i.e. the American Urological Association (AUA) symptom score, maximum flow rate (Qmax), post-void residual urine volume (PVR), voiding pressure at maximal flow (Pdet max) and prostatic volume determined by ultrasonography (PV) were measured initially and 6 months after treatment using a defined protocol. Complications were recorded during and up to 6 months after the treatment. As the variables were independent, the data were analysed using a paired t-test for each to assess the treatment effect for each group.

RESULTS

After TURP, all the variables improved significantly; after TUMT, the symptoms improved both clinically and statistically (P < 0.001), with the mean AUA symptom score decreasing from 18.4 to 5.2. However, none of the objective variables improved after TUMT. The energy delivered under software control correlated poorly with prostatic volume (r = 0.322). TUMT had considerably lower morbidity than TURP, but failure of ejaculation occurred in four of 18 sexually active men after TUMT.

CONCLUSIONS

Despite considerable improvement in their symptoms, TUMT using the Prostatron and Prostasoft v2.5 did not alleviate obstruction in patients with BPH. Patients treated using TUMT controlled by this software should be informed of the possibility of ejaculatory dysfunction.

Overexpression of leptin receptor predicts an unfavorable outcome in Middle Eastern ovarian cancer

Background

Recent epidemiological studies have suggested that obesity is associated with ovarian cancer. Obesity hormone leptin and its receptor (Ob-R) contribute to tumor development by enhancing cell growth and survival. This study was design to investigate the prevalence of leptin and Ob-R in Middle Eastern epithelial ovarian cancer (EOC) and to analyze the role of leptin and the mechanisms under its action in EOC tissue sample and cell lines.

Methods

The expression of leptin and Ob-R was examined by immunohistochemistry in a tissue microarray of 156 EOC samples. Proliferation of EOC cells in response to leptin was assessed by MTT assays, and its anti-apoptotic effects were determined by flow cytometry. Effect of leptin on PI3K/AKT signaling pathway was further determined by western blotting.

Results

In clinical samples, Ob-R overexpression was seen in 59.2% EOCs and was significantly associated with poor progression free survival (p = 0.0032). Furthermore, Ob-R expression was associated with anti apoptotic proteins Bcl-XL (p = 0.0035) and XIAP (p = 0.0001). In vitro analysis using EOC cell lines showed that leptin stimulated cell proliferation and inhibits apoptosis via activation of PI3K/AKT signaling pathway. Inhibition of PI3K activity by LY294002, a specific inhibitor of PI3-kinase abrogated leptin mediated PI3K/AKT signaling. Gene silencing of Ob-R with Ob-R siRNA in EOC cells resulted in down regulation of phospho-AKT and its down stream targets.

Conclusion

Our findings have potential clinical implication for EOC development and progression.