Phase transitions and critical phenomena in the liquid bridge under lateral acceleration

We study the shape of a liquid body under the influence of a lateral body force in a thin liquid bridge. The shape of the liquid body changes continuously or discontinuously depending on the volume of liquid body. We show that the transition from discontinuous to continuous change is described by the volume-induced phase transition driven by the lateral body force. The order parameter of the phase transition is the amount of shift of the center of mass of liquid body. Critical exponents of a mean-field model have been obtained by numerical calculation. We provide the validity of this critical behavior through the m(4) model of Landau theory of phase transition.

Extremely low doses of tissue factor pathway inhibitor decrease mortality in a rabbit model of septic shock

OBJECTIVE

We sought to determine the lowest dose of recombinant human tissue factor pathway inhibitor (TFPI) that can provide protection from lethality in a rabbit model of septic shock.

METHODS

Sepsis was induced in New Zealand white rabbits by intraperitoneal implantation of 7.0 ml of a solution containing hemoglobin (4.8 g/dl), porcine mucin (6 g/dl), and 0.8-1.4 x 10(4) viable Escherichia coli (strain O:18 K+). Gentamicin (5 mg/kg) was administered 4 h following surgery, and this dose was repeated every 12 h for 3 days. Beginning 4 h following the induction of sepsis, animals were treated with a bolus (1 ml) plus a continuous infusion (100 ml over 24) of either TFPI (various doses) or its vehicle. Four different doses of TFPI were studied, and each experiment included a contemporaneous control group. The primary outcome parameter was survival time. Results were analyzed using the Wilcoxen log rank test.

RESULTS

The average survival time for rabbits treated with the highest dose of TFPI tested (50 microg/kg bolus and 0.5 microg/kg per minute infusion) was 118 h, as compared to 81 h in vehicle-treated controls). The average survival time for septic rabbits treated with a much lower dose of TFPI (100 ng/kg bolus and 1.0 ng/kg per minute infusion) was 119 h as compared to 57 h in surviving vehicle-treated controls. Treatment with an even lower dose of TFPI (10 ng/kg bolus and 0.1 ng/kg per minute infusion) still produced a marginally significant prolongation of average survival time (80 h) relative to contemporaneously studied controls (47 h). When the dose of TFPI was decreased still further (1.0 ng/kg bolus and 0.01 ng/kg per minute infusion), average survival times were not significantly different between TFPI-treated and vehicle-treated rabbits (77 and 51 h, respectively).

CONCLUSIONS

Delayed infusion with remarkably low doses of recombinant human TFPI prolongs survival in a rabbit model of antibiotic-treated Gram-negative bacterial sepsis. In planning human trials of TFPI as an adjuvant treatment for sepsis it may be reasonable to use much lower doses of the agent than were heretofore contemplated.

Genomic structure, functional comparison, and tissue distribution of mouse Cd59a and Cd59b

CD59 is a crucial complement regulatory protein that inhibits the terminal step of the complement activation cascade by interfering with the binding of C9 to C5b-8, thus preventing the formation of the membrane attack complex (MAC). We recently reported that the mouse genome contains two Cd59 genes, while the human and rat genomes each contain only one Cd59 gene (Qian et al. 2000). Here, we describe the genomic structure, comparative activity, and tissue distribution of these two mouse genes, designated Cd59a and Cd59b. The mouse Cd59 genes encompass a total of 45.6 kb with each gene having four exons. Cd59a spans 19 kb, and Cd59b spans 15 kb, with approximately 11.6 kb of genomic DNA separating the two genes. The overall sequence similarity between Cd59a and Cd59b is approximately 60%. The sequence similarity between exon 2, exon 3, and exon 4 and the respective flanking regions between the two genes is over 85%, but exon 1 and its flanking regions are totally different. Comparative studies of the activity of both genes as inhibitors of MAC formation revealed that Cd59b has a specific activity that is six times higher than that of Cd59a. Using polyclonal antibodies specific to either Cd59a or Cd59b, we showed that Cd59a and Cd59b are both widely expressed in the kidneys, brain, lungs, spleen, and testis, as well as in the blood vessels of most mouse tissues. Interestingly, testicular Cd59a appeared to be expressed exclusively in spermatids, whereas Cd59b was expressed in more mature sperm cells. These results suggest that even though Cd59a and Cd59b are expressed in multiple tissues, they may play some different roles, particularly in reproduction.

Regulation of Staphylococcus aureus type 5 and type 8 capsular polysaccharides by CO(2)

Staphylococcus aureus expression of capsular polysaccharide type 5 (CP5) has been shown to be downregulated by CO(2). Here we show that CO(2) reduces CP5 expression at the transcriptional level and that CO(2) regulates CP8 expression depending on the genetic background of the strains. Growth in the presence of air supplemented with 5% CO(2) caused a significant decrease in CP8 expression in four S. aureus strains, a marginal effect in four strains, and higher CP8 expression in strain Becker. Absolute CP8 expression in the nine S. aureus strains differed largely from strain to strain. Four groups of strains were established due to sequence variations in the promoter region of cap5 and cap8. To test whether these sequence variations are responsible for the different responses to CO(2), promoter regions from selected strains were fused to the reporter gene xylE in pLC4, and the plasmids were electrotransformed into strains Becker and Newman. XylE activity was negatively regulated by CO(2) in all derivatives of strain Newman and was always positively regulated by CO(2) in all derivatives of strain Becker. Differences in promoter sequences did not influence the pattern of CP8 expression. Therefore, the genetic background of the strains rather than differences in the promoter sequence determines the CO(2) response. trans-acting regulatory molecules may be differentially expressed in strain Becker versus strain Newman. The strain dependency of the CP8 expression established in vitro was also seen in lung tissue sections of patients with cystic fibrosis infected with CP8-positive S. aureus strains.

Apoptotic activity of doxazosin on prostate stroma in vitro is mediated through an autocrine expression of TGF-beta1

BACKGROUND

Doxazosin, an alpha-adrenergic antagonist, has been shown to induce apoptosis in prostatic stromal cells. The mechanism of this apoptotic action by Doxazosin remains undefined. The present study was carried out to demonstrate that the effect of Doxazosin on apoptosis of prostate stromal cells is mediated through an autocrine action of TGF-beta1.

METHODS

Primary cultures of human prostate cells were treated with varying concentrations of Doxazosin (0, 0.1, 1, 10, and 100 microM) for a period up to 3 days. At the end of the 3-day culture, cell numbers were counted. Apoptosis was assessed by a colorimetric terminal deoxyribonucleotide transferase labeling technique. TGF-beta1 was determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Compared to control cultures, cell numbers were significantly decreased as much as 68.4% in cultures treated with 10 microM of Doxazosin after 3 days incubation, while apoptosis increased by 64.7% in cultures treated with the same concentration of Doxazosin after 24 h. This decrease in cell number was reversed when antibody to TGF-beta1 was added to these cultures. Addition of TGF-beta1 (0, 1.0, and 10 ng/mL) to the cultures also decreased the cell numbers. Quantitation of TGF-beta1 in lysates of cells by ELISA revealed that the cells treated with Doxazosin (10 microM) produced as much as 62.5% more TGF-beta1 than in that of untreated cells.

CONCLUSIONS

These results demonstrate that the apoptotic effect of Doxazosin on human prostatic stromal cells is mediated through an autocrine production of TGF-beta1.

Mutations in the novel protocadherin PCDH15 cause Usher syndrome type 1F

We have determined the molecular basis for Usher syndrome type 1F (USH1F) in two families segregating for this type of syndromic deafness. By fluorescence in situ hybridization, we placed the human homolog of the mouse protocadherin Pcdh15 in the linkage interval defined by the USH1F locus. We determined the genomic structure of this novel protocadherin, and found a single-base deletion in exon 10 in one USH1F family and a nonsense mutation in exon 2 in the second. Consistent with the phenotypes observed in these families, we demonstrated expression of PCDH15 in the retina and cochlea by RT-PCR and immunohistochemistry. This report shows that protocadherins are essential for maintenance of normal retinal and cochlear function.

Minimally invasive approaches to mandibular fractures

Excellence in mandibular fracture repair requires anatomic restoration of the displaced bone segments, maintenance of the reduction until bone union has been confirmed, and minimization of surgical stigmata. Repairs should ideally be cost-effective, reproducible, adaptable, and expeditiously executed. Fractures of two subregions of the mandible, the condylar neck and the symphysis, can benefit from minimally invasive surgical techniques. The use of these techniques in the mandible is reviewed.

The effect of tobacco smoke, nicotine, and cotinine on the mutagenicity of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL)

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is a rodent carcinogen that is metabolically derived from carbonyl reduction of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). NNAL can be pyridine N-oxidized to form NNAL-N-oxide, or conjugated to form NNAL-glucuronide - non-genotoxic metabolites that can be excreted in urine. Alternatively, NNAL can be alpha-hydroxylated at the methyl and methylene carbons adjacent to the nitroso group to generate electrophiles that can react with biological macromolecules, such as DNA and proteins. Our laboratory has previously demonstrated that the mutagenicity of NNK was significantly inhibited by the aqueous extract of tobacco smoke, as well as pyridine alkaloids in cigarette smoke, such as nicotine, cotinine and nornicotine. Given the structural similarity between NNK and NNAL, and the metabolic activation of both by cytochromes P450, we hypothesized that there may be a similar inhibition of NNAL metabolism, and consequently, inhibition of the mutagenic activity of NNAL by tobacco smoke and its pyridine alkaloid constituents. In the present study, we evaluated the ability of two pyridine alkaloids (nicotine and cotinine) and aqueous cigarette smoke condensate extract (ACTE) to inhibit the mutagenicity of NNAL in Salmonella typhimurium strain TA1535 in the presence of a metabolic activation system (S9). Both pyridine alkaloids tested, as well as ACTE, inhibited the mutagenicity of NNAL in a concentration-dependent manner. The observed reductions in mutagenicity were not the result of cell killing due to cytotoxicity. These results demonstrate that tobacco smoke contains pyridine alkaloids, as well as other unidentified constituents that inhibit the mutagenicity of NNAL, a major metabolite of NNK.

Oligodendroglia in the avian retina: immunocytochemical demonstration in the adult bird

Immunohistochemical techniques were used in conjunction with an avian-specific probe for oligodendrocyte (OLG) marker, the antibody for transferrin binding protein (TfBP), to study the characteristics and distribution of OLGs in the retina of chickens and quails. For comparison, other antibodies such as myelin basic protein, Rip, and those for labeling Müller cells and microglia were used. A large population of OLGs was found to be distributed throughout the retina, with the distinct pattern of a central-to-peripheral gradient. It was possible to detect a spectrum of OLG morphology that bore a resemblance to the subtype of the mammalian central nervous system. In addition to these mature OLGs, limited numbers of TfBP-positive (TfBP(+)) cells with the morphology of immature OLGs were found in the immediate vicinity of the optic head. The majority of OLGs appeared in the ganglion cell layer throughout the retina, whereas OLGs in the nerve fiber layer were seen mainly in the central zone of the retina, near the optic nerve head. Double-labeling experiments showed that OLGs were associated with myelin only in the central region, where the majority of retinal OLGs occurred, but not toward the periphery of the retina. The present study is the first comprehensive analysis of the morphological features and spatial distribution of OLGs in the adult avian retina and provides in vivo evidence for the existence of a substantial population of both mature and immature OLGs in the retina of adult birds. The putative functions of TfBP(+) OLGs including myelination and the tropic role of the ganglion cells are discussed in conjunction with the physical properties of TfBP and structural characteristics of the avascular retina of birds.

DNA mismatch repair enzyme activity and gene expression in prostate cancer

Microsatellite instability (MSI) of short repetitive sequences in human chromosomal DNA can result from defective DNA mismatch repair function in tumor cells. We hypothesize that DNA mismatch repair (MMR) activity is down-regulated during prostatic carcinogenesis. To test this hypothesis, MMR activities and mismatch repair-related genes were analyzed in five different prostate cancer cell lines. Our results demonstrate that MMR activities were decreased as compared to MMR proficient HeLa cells. Interestingly, LNCaP, PC-3 and DU145 had much lower MMR activities as compared to DUPro and TSUPr1. The MMR-related genes (hMLH1, hPMS1, hPMS2, hMSH2, hMSH3, hMSH6) showed mRNA transcripts in all prostate cancer cell lines. However, Western blotting showed decreased or absent hMLH1 protein expression in PC-3, DU145, DUPro and TSUPr1 cells. Similarly, the hMSH2 protein expression was low or absent in DU145 and LNCaP cells. This is the first report that demonstrates decreased MMR activities is associated with low expression of hMLH1, hMSH2 and other MMR-related proteins in prostate cancer.

The synthesis, discovery, and development of a highly promising class of microtubule stabilization agents: curative effects of desoxyepothilones B and F against human tumor xenografts in nude mice

We have evaluated two synthetic epothilone analogues lacking the 12,13-epoxide functionality, 12,13-desoxyepothilone B (dEpoB), and 12,13-desoxyepothilone F (dEpoF). The concentrations required for 50% growth inhibition (IC(50)) for a variety of anticancer agents were measured in CCRF-CEM/VBL1000 cells (2,048-fold resistance to vinblastine). By using dEpoB, dEpoF, aza-EpoB, and paclitaxel, the IC(50) values were 0.029, 0.092, 2.99, and 5.17 microM, respectively. These values represent 4-, 33.5-, 1,423- and 3,133-fold resistance, respectively, when compared with the corresponding IC(50) in the parent [nonmultiple drug-resistant (MDR)] CCRF-CEM cells. We then produced MDR human lung carcinoma A549 cells by continuous exposure of the tumor cells to sublethal concentrations of dEpoB (1.8 yr), vinblastine (1.2 yr), and paclitaxel (1.8 yr). This continued exposure led to the development of 2.1-, 4,848-, and 2,553-fold resistance to each drug, respectively. The therapeutic effect of dEpoB and paclitaxel was also compared in vivo in a mouse model by using various tumor xenografts. dEpoB is much more effective in reducing tumor sizes in all MDR tumors tested. Analysis of dEpoF, an analog possessing greater aqueous solubility than dEpoB, showed curative effects similar to dEpoB against K562, CCRF-CEM, and MX-1 xenografts. These results indicate that dEpoB and dEpoF are efficacious antitumor agents with both a broad chemotherapeutic spectrum and wide safety margins.

Economic analysis of four triple regimens for the treatment of Helicobacter pylori-related peptic ulcer disease in in-patient and out-patient settings in Hong Kong

BACKGROUND

One-week triple regimens have been shown to be effective for the treatment of Helicobacter pylori-related peptic ulcer disease.

AIM

To conduct an economic analysis of four triple regimens for the treatment of H. pylori-related peptic ulcer disease from the perspective of a public health organization in Hong Kong.

METHODS

Records of 200 patients with H. pylori-related peptic ulcer disease, who had previously participated in a randomized comparison of ranitidine bismuth citrate (RBC) with amoxicillin and clarithromycin (RAC), omeprazole with amoxicillin and clarithromycin (OAC), RBC with metronidazole and tetracycline (RMT), or, colloidal bismuth subcitrate with metronidazole and tetracycline (BMT) in either in-patient or out-patient setting were reviewed.

RESULTS

Fifty patients were excluded because of incomplete documentation or lack of peptic ulcer. In the out-patient group (n=72), the median direct costs of the RAC group (HK $ 5094) were lower those of the BMT (HK $ 5400), RMT (HK $ 5394), or OAC (HK $ 5440) groups, but the difference was significant only between the RAC and BMT groups (P < 0.05). In the in-patient group (n=78), the median direct costs of the RMT group (HK $ 8524) were significantly lower than those of the OAC (HK $ 13 871) and RAC (HK $ 12 092) groups (P < 0.05), but were similar to those of the BMT group (HK $ 8758).

CONCLUSIONS

RAC and RMT are the least costly regimens for out-patient and in-patient treatment, respectively, of H. pylori-related peptic ulcer disease in Hong Kong.

Cavities of alpha(1)-antitrypsin that play structural and functional roles

The native form of inhibitory serine protease inhibitors (serpins) is strained, which is critical for their inhibitory activity. Previous studies on stabilizing mutations of alpha(1)-antitrypsin, a prototype of serpins, indicated that cavities provide a structural basis for the native strain of the molecule. We have systematically mapped the cavities of alpha(1)-antitrypsin that play such structural and functional roles by designing cavity-filling mutations at residues that line the walls of the cavities. Results show that energetically unfavorable cavities are distributed throughout the alpha(1)-antitrypsin molecule, and the cavity-filling mutations stabilized the native conformation at 8 out of 10 target sites. The stabilization effect of the individual cavity-filling mutations of alpha(1)-antitrypsin varied (0.2-1.9 kcal/mol for each additional methylene group) and appeared to depend largely on the structural flexibility of the cavity environment. Cavity-filling mutations that decreased inhibitory activity of alpha(1)-antitrypsin were localized in the loop regions that interact with beta-sheet A distal from the reactive center loop. The results are consistent with the notion that beta-sheet A and the structure around it mobilize when alpha(1)-antitrypsin forms a complex with a target protease.

Does ascorbic acid prevent retinopathy during interferon therapy in patients with chronic hepatitis C?

PURPOSE

Ascorbic acid was administered to patients with chronic hepatitis C to elucidate the mechanism of onset of retinopathy during interferon (IFN) therapy, and its prevention.

METHODS

The subjects were 62 patients with chronic hepatitis C who had been admitted to our hospital. For the IFN therapy, 6 MIU of natural IFN-alpha, or 10 MIU of recombinant human IFN-alpha 2b was administered every day for the first 2 weeks, followed by administration three times a week for 22 weeks. The patients were randomly assigned to a group receiving 600 mg/day of ascorbic acid or a group not receiving ascorbic acid (control group). The optic fundi were examined by ophthalmologists before the IFN therapy began and subsequently at weeks 2 and 4 and then every 4 weeks during the IFN therapy.

RESULTS

Retinopathy was found in 9 of the 31 patients (29%) in the ascorbic acid-treated group and in 11 of the 31 patients (35%) in the control group. The cumulative incidence of hemorrhage in the ascorbic acid-treated group was lower than that in the control group during the IFN therapy, but the difference between the two groups was not significant (P = 0.186). The cumulative incidence of cotton-wool spots in the ascorbic acid-treated group was almost same as that in the control group during the IFN therapy. The median platelet counts before the therapy was begun were 11.8 x 10(4)/mm2 in the group with hemorrhage and 16.6 x 10(4)/mm2 in the group without, and the lowest platelet counts during IFN therapy were 7.3 x 10(4)/mm3 in the group with hemorrhage and 9.5 x 10(4)/mm3 in the group without, indicating significantly lower values in the group with hemorrhage (P = 0.018 and P = 0.020, respectively). The lowest platelet counts during IFN therapy were 7.4 x 10(4)/mm3 in the group with cotton-wool spots and 9.7 x 10(4)/mm3 in the group without, indicating a significantly lower value in the group with cotton-wool spots (P = 0.036).

CONCLUSIONS

Ascorbic acid was not considered to be useful for the prevention of the retinopathy associated with IFN therapy in patients with chronic hepatitis C.

Loss of mismatch repair activity in simian virus 40 large T antigen-immortalized BPH-1 human prostatic epithelial cell line

Simian virus 40 large T antigen (SVLTAg) has been used to immortalize cells; however, the mechanism leading to immortalization is still unclear. We hypothesize that DNA mismatch repair (MMR) activity is important during SVLTAg-induced immortalization. To test this hypothesis, we used the SVLTAg-immortalized cell line BPH-1 derived from human benign prostate epithelial cells to analyze MMR activity and the expression of MMR genes (hMLH1, hPMS1, hPMS2, hMSH2, hMSH3, and hMSH6). The results demonstrated that BPH-1 cells were deficient in repairing G:T, A:C, and G:G mispairs in bacteriophage M13mp2. Reverse-transcription polymerase chain reaction experiments indicated MMR genes (hMSH3, hMSH6, and hPMS1) were expressed at a low level in BPH-1 cells. In contrast, all six MMR genes were expressed in human benign prostate hyperplasia tissues. Downregulation of hMSH3, hMSH6, and hPMS1 genes is not a result of the hypermethylation mechanism because demethylation with 5-aza-2'-deoxycytidine did not restore expression of these genes. Although the hMLH1 gene is expressed in BPH-1 cells, western blotting and exon analyses demonstrated that hMLH1 was mutated and/or deleted in BPH-1 cells.

Genome-wide detection of alternative splicing in expressed sequences of human genes

We have identified 6201 alternative splice relationships in human genes, through a genome-wide analysis of expressed sequence tags (ESTs). Starting with approximately 2.1 million human mRNA and EST sequences, we mapped expressed sequences onto the draft human genome sequence and only accepted splices that obeyed the standard splice site consensus. A large fraction (47%) of these were observed multiple times, indicating that they comprise a substantial fraction of the mRNA species. The vast majority of the detected alternative forms appear to be novel, and produce highly specific, biologically meaningful control of function in both known and novel human genes, e.g. specific removal of the lysosomal targeting signal from HLA-DM beta chain, replacement of the C-terminal transmembrane domain and cytoplasmic tail in an FC receptor beta chain homolog with a different transmembrane domain and cytoplasmic tail, likely modulating its signal transduction activity. Our data indicate that a large proportion of human genes, probably 42% or more, are alternatively spliced, but that this appears to be observed mainly in certain types of molecules (e.g. cell surface receptors) and systemic functions, particularly the immune system and nervous system. These results provide a comprehensive dataset for understanding the role of alternative splicing in the human genome, accessible at http://www.bioinformatics.ucla.edu/HASDB.

Neoadjuvant chemoradiation for rectal cancer: analysis of clinical outcomes from a 13-year institutional experience

OBJECTIVE

To examine clinical outcomes in patients receiving neoadjuvant chemoradiation for locally advanced rectal adenocarcinoma.

SUMMARY BACKGROUND DATA

Preoperative radiation therapy, either alone or in combination with 5-fluorouracil-based chemotherapy, has proven both safe and effective in the treatment of rectal cancer. However, data are lacking regarding which subgroups of patients benefit from the therapy in terms of decreased local recurrence and increased survival rates.

METHODS

A retrospective chart review was performed on 141 consecutive patients who received neoadjuvant chemoradiation (5-fluorouracil +/- cisplatin and 4,500-5,040 cGy) for biopsy-proven locally advanced adenocarcinoma of the rectum. Surgery was performed 4 to 8 weeks after completion of chemoradiation. Standard statistical methods were used to analyze recurrence and survival.

RESULTS

Median follow-up was 27 months, and mean age was 59 years (range 28-81). Mean tumor distance from the anal verge was 6 cm (range 1-15). Of those staged before surgery with endorectal ultrasound or magnetic resonance imaging, 57% of stage II patients and 82% of stage III patients were downstaged. The chemotherapeutic regimens were well tolerated, and resections were performed on 140 patients. The percentage of sphincter-sparing procedures increased from 20% before 1996 to 76% after 1996. On pathologic analysis, 24% of specimens were T0. However, postoperative pathologic T stage had no effect on either recurrence or survival. Positive lymph node status predicted increased local recurrence and decreased survival.

CONCLUSIONS

Neoadjuvant chemoradiation is safe, effective, and well tolerated. Postoperative lymph node status is the only independent predictor of recurrence and survival.

Pediatric cardiac emergencies

Successful management of pediatric cardiac emergencies requires an accurate diagnosis to institute an appropriate plan of therapy. The diagnosis, however, is not always straightforward, as evidenced by the nonspecific clinical picture that can be presented by congenital heart defects. Entertaining the possibility of a cardiac problem in neonates with pulmonary symptoms unresponsive to standard therapies is crucial for successful management of patients with congenital heart disease. In addition to ventilatory support, prostaglandin E1 infusions or emergency interventional cardiac catheterization is often a life-saving initial measure in patients with acutely decompensated congenital cardiac lesions that require a patent ductus arteriosus for survival. Pericardial tamponade is associated with various acquired and iatrogenic causes. Emergent pericardiocentesis is mandatory when cardiovascular compromise occurs. The goal of anesthetic management is to maintain cardiac output. With the increasing use of central venous catheters in neonatal ICUs and the high mortality rate for central venous catheter-related cardiac tamponade, the diagnosis must be considered in any patient with a central venous catheter in situ who acutely develops unexplained hypotension, bradycardia, and diminished pulses. Arrhythmias also can cause hemodynamic instability in infants and children. Supraventricular tachycardia is by far the most common emergently presenting arrhythmia in the pediatric population. Unstable patients require immediate intravenous adenosine or synchronized cardioversion. Complete heart block is rare, but it can lead to congestive heart failure and occasionally to cardiovascular collapse and sudden death. Emergency treatment of complete heart block includes pharmacologic support and temporary or permanent pacemaker placement as indicated. In infants, congestive heart failure usually is related to congenital heart disease, whereas in older children, it tends to be secondary to an acquired cause. Supportive measures, fluid restriction, and inotropic support are the principles of initial treatment. Prompt recognition and initiation of appropriate therapy in pediatric cardiac emergencies are essential for favorable outcomes.

Effects of oral estrogen and progestin on the lower urinary tract among female nursing home residents

OBJECTIVE

To examine the effects of oral estrogen/progestin on incontinence and related lower urinary tract conditions among female nursing home (NH) residents.

DESIGN

Randomized placebo-controlled trial.

SETTING

Five NHs.

PARTICIPANTS

Thirty-two incontinent female residents of average age 88.

MEASUREMENTS

Subjects were randomized to receive either oral estrogen (0.625 mg) combined with progesterone (2.5 mg) or placebo, daily for 6 months. Measures of incontinence severity, the clinical appearance of the vagina, vaginal and urethral cytology, and urine and vaginal cultures were made at baseline, 3 months, and 6 months. In addition to active drug or placebo, all subjects received regular toileting assistance (prompted voiding) by trained research aides during 3-day data-collection periods to compensate for mobility and cognitive impairments.

RESULTS

At 3 and 6 months there were no significant differences between the groups in the severity of incontinence, the prevalence of bacteriuria, or the results of vaginal cultures. Several clinical findings associated with atrophic vaginitis improved more in the active than the placebo group and vaginal pH and vaginal and urethral cytology exhibited a partial estrogenic effect.

CONCLUSIONS

Our results must be interpreted with caution because of the size and the select nature of our subject sample. Up to 6 months of oral estrogen had only a partial estrogenic effect on vaginal and urethral epithelium and no clinical effects in this patient population. We believe that future studies of estrogen for urinary incontinence in frail NH residents should utilize a topical preparation and consider targeting urinary tract infection as an additional outcome measure.

Energy loss of fast quarks in nuclei

We report an analysis of the nuclear dependence of the yield of Drell-Yan dimuons from the 800 GeV/c proton bombardment of 2H, C, Ca, Fe, and W targets. Employing a new formulation of the Drell-Yan process in the rest frame of the nucleus, this analysis examines the effect of initial-state energy loss and shadowing on the nuclear-dependence ratios versus the incident proton's momentum fraction and dimuon effective mass. The resulting energy loss per unit path length is -dE/dz = 2.32+/-0.52+/-0.5 GeV/fm. This is the first observation of a nonzero energy loss of partons traveling in a nuclear environment.