Subducting serpentinites release reduced, not oxidized, aqueous fluids.

The observation that primitive arc magmas are more oxidized than mid-ocean-ridge basalts has led to the paradigm that slab-derived fluids carry SO2 and CO2 that metasomatize and oxidize the sub-arc mantle wedge. We combine petrography and thermodynamic modelling to quantify the oxygen fugacity (fO2) and speciation of the fluids generated by serpentinite dehydration during subduction. Silicate-magnetite assemblages maintain fO2 conditions similar to the quartz-fayalite-magnetite (QFM) buffer at fore-arc conditions. Sulphides are stable under such conditions and aqueous fluids contain minor S. At sub-arc depth, dehydration occurs under more reducing conditions producing aqueous fluids carrying H2S. This finding brings into question current models in which serpentinite-derived fluids are the cause of oxidized arc magmatism and has major implications for the global volatile cycle, as well as for redox processes controlling subduction zone geodynamics.

Outreach with street-involved youth: a quantitative and qualitative review of the literature.

Outreach workers meet with street-involved youth in their environment, and attempt to engage them in services vital to their well-being. The goal of this study is to conduct a systematic review of both the quantitative and qualitative research that explores outreach with street-involved youth. Using 16 outreach programs with quantitative information, our meta-analysis found that 63% of youth who are contacted through outreach later participate in the offered service. Our meta-synthesis of 31 qualitative articles on outreach uncovered 13 themes across 4 conceptual domains of interest. Themes pertaining to the therapeutic relationship, flexibility, and youth-centric programming had a large presence among the majority of the articles. Outreach with street-involved youth, when characterized through a strong bond between worker and youth, is an effective strategy for involving youth in agency services.

Element partitioning: the role of melt structure and composition.

We segregated coexisting gabbroic and granitic melts by centrifuging them at high pressures and temperatures and measured the trace element compositions of the melts by laser ablation inductively coupled plasma mass spectrometry. Our results demonstrate that the effect of melt structure contributes about one order of magnitude to crystal/melt partition coefficients. Partitioning of alkali and alkaline earth elements strongly depends on field strength: Amphoteric and lone pair electron elements partition into the polymerized granitic melt; and rare earth, transition, and high field strength elements coordinated by nonbridging oxygens partition remarkably similar into the gabbroic melt. A regular solution model predicts these effects.

Eating disturbances in girls with diabetes: the contribution of adolescent self-concept, maternal weight and shape concerns and mother-daughter relationships.

BACKGROUND: This study examined the relative contribution of adolescent self-concept, maternal weight and shape concerns (WSC), and mother-daughter relationships to eating disturbances among girls with type 1 diabetes mellitus (DM). METHOD: Eighty-eight adolescent girls (mean = 15.0 years, S.D. = 2.2) and their mothers completed self-report measures of disordered eating and weight control behaviours, with teens also reporting on disturbed eating and body attitudes. Based on reported symptoms, adolescents were classified as highly (N = 18), mildly (N = 30) and non-eating disturbed (N = 40). Self-concept was assessed by adolescent self-report. Mother-daughter relationships were assessed by adolescent self-report and by observed mother-daughter interactions that were rated using a macroanalytic coding system that assesses intimacy and autonomy in these relationships. RESULTS: Hierarchical regressions illustrated that adolescent self-concept deficits, maternal WSC, and impaired mother-daughter relationships significantly predicted eating disturbances in girls with DM, accounting for 57% of the variance. Mothers who engaged in dieting and binge-eating were more impaired in their ability to support their daughters' emerging autonomy. The quality of mother-daughter relationships partly mediated the influence of maternal WSC on adolescent eating disturbances. Moreover, the impact of maternal WSC and mother-daughter relationships on eating disturbances was mediated by adolescent self-concept. CONCLUSIONS: Findings illustrate two pathways through which mother-daughter relationships may impact upon risk of eating disturbances in girls with DM and highlight the need to evaluate family-based interventions specifically tailored for this high-risk population.

Metamorphic devolatilization of subducted marine sediments and the transport of volatiles into the Earth's mantle.

Volatiles, most notably CO2, are recycled back into the Earth's interior at subduction zones. The amount of CO2 emitted from arc volcanism appears to be less than that subducted, which implies that a significant amount of CO2 either is released before reaching the depth at which arc magmas are generated or is subducted to deeper depths. Few high-pressure experimental studies have addressed this problem and therefore metamorphic decarbonation in subduction zones remains largely unquantified, despite its importance to arc magmatism, palaeoatmospheric CO2 concentrations and the global carbon cycle. Here we present computed phase equilibria to quantify the evolution of CO2 and H2O through the subduction-zone metamorphism of carbonate-bearing marine sediments (which are considered to be a major source for CO2 released by arc volcanoes). Our analysis indicates that siliceous limestones undergo negligible devolatilization under subduction-zone conditions. Along high-temperature geotherms clay-rich marls completely devolatilize before reaching the depths at which arc magmatism is generated, but along low-temperature geotherms, they undergo virtually no devolatilization. And from 80 to 180 km depth, little devolatilization occurs for all carbonate-bearing marine sediments. Infiltration of H2O-rich fluids therefore seems essential to promote subarc decarbonation of most marine sediments. In the absence of such infiltration, volatiles retained within marine sediments may explain the apparent discrepancy between subducted and volcanic volatile fluxes and represent a mechanism for return of carbon to the Earth's mantle.

ESkine, a novel beta-chemokine, is differentially spliced to produce secretable and nuclear targeted isoforms.

Using the murine embryonal stem cell system, we have identified a novel gene encoding a highly divergent member of the beta-chemokine family of proinflammatory mediators and have called this protein ESkine. Much of the coding sequence for ESkine overlaps with the 3'-end of a novel interleukin 11 receptor alpha-like sequence on murine chromosome 4. ESkine is produced as two splice variants. One of these variants encodes a classical chemokine with an associated signal peptide, while the other variant (PESKY) possesses the main body of the chemokine but has replaced the signal peptide with an alternative stretch of amino acids that allows for nuclear targeting of this isoform. This differential splicing arises as a result of alternative 5' exon usage. These differentially spliced forms are expressed at discrete tissue loci. Thus, while ESkine is highly expressed in the placenta, PESKY is mainly expressed in the Testes and brain and weakly in the developing embryo. Studies on the proinflammatory properties of ESkine reveal it to be active in inducing polarization of CD4(+) T cells but to be inactive on other hemopoietic cellular populations.

The BPV-4 co-carcinogen quercetin induces cell cycle arrest and up-regulates transcription from the LCR of BPV-4.

Bracken fern is the environmental co-carcinogen of BPV-4 in the induction of neoplasias of the upper alimentary canal of cattle. The flavonoid quercetin is one of the most potent and best characterised mutagens present in the fern. We have shown that transfection with BPV-4 DNA and exposure to a single dose of quercetin leads to tumorigenic transformation of primary bovine cells. We now show that quercetin induces cell cycle arrest and up-regulates transcription from the BPV-4 long control region (LCR). This up-regulation is mediated by a 21 nucleotide-long cis-element in the LCR, designated QRE-1, which is located immediately downstream of the TATA box. Cellular proteins bind to QRE-1 and removal or substitution of QRE-1 lead to the abrogation of the response to quercetin. As expression of the viral oncogenes is controlled by the LCR, perturbation in this control and increased oncoprotein expression are likely to contribute to fully malignant cell transformation by overcoming the cell cycle arrest induced by quercetin, thus forcing damaged cells to proliferate.

Locally recurrent prostate tumors following either radiation therapy or radical prostatectomy have changes in Ki-67 labeling index, p53 and bcl-2 immunoreactivity.

PURPOSE: We compare the biological phenotype of recurrent prostatic tumors after definitive local therapy (radiation or radical prostatectomy) with that of the same tumors before treatment. MATERIALS AND METHODS: Cellular proliferation (Ki-67 labeling index), p53 nuclear reactivity and bcl-2 immunoreactivity were determined in pretreatment and posttreatment tumor specimens from 13 patients with local tumor recurrence following radiation, and in 18 patients with local tumor recurrence following radical prostatectomy. RESULTS: Mean Ki-67 labeling index increased approximately 2-fold in locally recurrent tumors after radiation (10.5 versus 5.6%, p=0.0008) or surgery (6.0 versus 3.2%, p=0.0025) when compared with pretreatment tumors. We noted p53 nuclear reactivity in a significantly higher proportion of recurrences than in pretreatment tumors following radiation (54 versus 8%, p=0.032) and surgery (39 versus 5%, p=0.022). Although bcl-2 immunoreactivity was also seen in a higher proportion of recurrent tumors, this difference did not reach statistical significance for either radiation or surgery. CONCLUSIONS: Recurrent tumors following either radiation or surgery differ significantly from the corresponding pretreatment tumors with respect to cellular proliferation and p53 nuclear reactivity.

Accelerated tumor proliferation rates in locally recurrent prostate cancer after radical prostatectomy.

PURPOSE: We compared the growth rates of primary cancer and prostatic fossa recurrence after radical prostatectomy. MATERIALS AND METHODS: Tumor proliferative rates were studied in 26 patients with biopsy proved prostatic fossa recurrences after radical prostatectomy. Proliferation was calculated in the prostatectomy specimens and in recurrent cancer using Ki-67 antibody to detect dividing cells. RESULTS: Mean and median labeling indexes for radical prostatectomy specimens were 2.96 and 2.51, respectively. Labeling indexes in locally recurrent tumors were significantly higher (mean 6.47, median 5.59, p < 0.001). The increase in labeling index between parent and recurrent tumors was unrelated to pathological staging at prostatectomy or interval from radical prostatectomy. CONCLUSIONS: Tumors that recur locally after radical prostatectomy appear to have a higher proliferative rate compared to parent tumors.

Prostate-specific antigen after cryosurgical ablation of the prostate. Defining the appropriate response.

The ability of prostate-specific antigen (PSA) to predict long-term cure after cryotherapy for localized prostate cancer is not known because experience with this treatment modality is limited; however, it appears that a PSA value of 0.5 ng/mL or less at 6 months or longer after cryotherapy is associated with a high probability of a negative post-treatment biopsy (greater than 95%). An undetectable PSA (less than 0.1 ng/mL) 3 months after the procedure is associated with a likelihood of a negative biopsy at 6 months and low, stable PSA levels up to 2 years.

Cryosurgery for locally advanced (T3) prostate cancer.

Cryosurgery of prostate cancer results in epithelial destruction. An undetectable serum prostate-specific antigen and absence of cancer by biopsy is related to cancer stage. The best results are seen in patients with low stage disease. Recurrence is more common in those patients with seminal vesicle invasion or apical involvement by cancer. Morbidity is not insignificant. The risk of urinary retention can be minimized by the use of an effective urethral warming device and more prolonged urethral catheterization after the procedure. Impotence is common in patients who undergo complete cryoablation of the prostate.

Should cryosurgery be considered a therapeutic option in localized prostate cancer?

Cryosurgical ablation of the prostate currently is under investigation as a potential treatment for localized prostate cancer. Results to date indicate that the majority of patients have negative biopsies and a marked reduction in prostate-specific antigen levels following cryotherapy. This treatment, however, is associated with significant side effects, notably bladder outflow obstruction, impotence, and incontinence, and its long-term durability is still unknown.

Ultrasound evaluation of the penis for assessment of impotence.

Image directed Doppler ultrasonography of the cavernous arteries provides functional, quantifiable assessment of penile arterial flow during a pharmacological erection. In this respect, this modality is superior to arteriography as a means of evaluating arteriogenic impotence. Peak flow velocity, arterial dilatation, and vessel pulsation are the most reliable ultrasonic indicators of arterial health. Aberrant arterial anatomy should be noted as this may contribute significantly to total penile blood flow. A thorough understanding of erectile physiology and anatomy is necessary to properly perform and interpret Doppler ultrasound results.

Cryosurgical treatment of localized prostate cancer (stages T1 to T4): preliminary results.

PURPOSE: We determined the posttreatment biopsy results, prostate specific antigen (PSA) levels and complications associated with cryosurgical ablation of the prostate performed for localized prostate cancer. MATERIALS AND METHODS: Within 18 months 102 patients underwent cryosurgery as definitive therapy for localized prostate cancer. Mean patient age was 68 years and 57% had advanced local disease (stage T3 or T4). Mean preoperative PSA was 21.8 ng./ml. RESULTS: PSA was undetectable at 6 months in 48% of patients who received no androgen deprivation therapy following cryosurgery. Of 91 patients with postoperative biopsies 77% had no evidence of cancer but 71% had benign epithelial a elements. The complication rate (excluding impotence) was 51%. Biopsy and PSA results improved with experience and changes in technique, that is double freezing, more lateral placement of cryoprobes and more aggressive freezing beyond the prostatic capsule. The most recent cohort of 77 patients had a detectable PSA rate of 23% and a positive post-cryosurgical biopsy rate of 11%. The most common serious complication encountered was bladder outflow obstruction requiring transurethral resection in 23% of the patients. Impotence occurred in 84% of patients potent preoperatively. CONCLUSIONS: Cryosurgical ablation of the prostate can result in negative posttreatment biopsies and undetectable serum PSA levels. However, it is associated with significant side effects and the long-term durability of the procedure is unknown.

Voiding dysfunction in human immunodeficiency virus infections.

PURPOSE: We prospectively evaluated the current spectrum of urodynamic pathology in patients infected with human immunodeficiency virus (HIV) who presented with voiding dysfunction. MATERIALS AND METHODS: We obtained a directed genitourinary and neurological history, and performed a physical examination and urodynamic testing in 18 patients. A 4-channel membrane urethral catheter was used to record intravesical and intraurethral pressures simultaneously. RESULTS: Detrusor hyperreflexia was present in 28% of our patients and detrusor-sphincter dyssynergia in 28%. Detrusor areflexia, previously described as the most frequent abnormality, was uncommon in our series (6% of patients). CONCLUSIONS: This changing proportion of urodynamic diagnoses may reflect a changing pattern of neurological manifestations of HIV infection due to more aggressive management. Urodynamic evaluation remains critical for precise diagnosis and treatment in patients with HIV who present with urinary symptoms.

Local recurrence after radical prostatectomy: characteristics in size, location, and relationship to prostate-specific antigen and surgical margins.

OBJECTIVES: To define the sonographic characteristics of local cancer recurrence after radical prostatectomy. METHODS: in 114 patients with an elevated prostate-specific antigen (PSA) and negative bone scan, 156 ultrasound-guided prostate fossa biopsies were carried out. RESULTS: in 53.5%, biopsy proved local recurrence. More than one ultrasound-guided biopsy session was required to make the diagnosis in 33% of patients. Local recurrence was seen on ultrasound at the anastomotic site (66%), the bladder neck (16%), and posterior to the trigone (13%). in 5% of patients there was a normal-appearing anastomotic site. Transrectal ultrasound was greater than 90% sensitive in detecting local recurrence, but lacked specificity. Examination of the radical prostatectomy specimens in patients with local recurrence showed positive surgical margins in 66% and organ-confined disease in 20%. CONCLUSIONS: Transrectal ultrasonography is a useful adjunct to PSA and digital rectal examination in the detection of local recurrences following radical prostatectomy.

Prevalence and repair of inguinal hernias in children with bladder exstrophy.

PURPOSE: We delineated the prevalence, recurrence rates and optimal treatment of inguinal hernia in the exstrophy population. MATERIALS AND METHODS: Of 181 children with exstrophy followed at our hospital inguinal hernias developed in 121 (66.8%). RESULTS: In a 12-year period inguinal hernias developed in 81.8% of the boys and 10.5% of the girls. In 18.2% of the cases the hernia was repaired via a preperitoneal approach at the same time as exstrophy closure. The remaining patients underwent an inguinal operation. Most patients had a wide defect at the internal ring in addition to a patent processus vaginalis. The overall recurrence rate was 8.3%. The incidence of synchronous or asynchronous bilaterality was 81.8%. CONCLUSIONS: Children with bladder exstrophy should be carefully examined for inguinal hernias before bladder closure. If a unilateral hernia is present, the contralateral side should be explored. Careful preperitoneal repair should emphasize repair of the internal ring.

Renal transplantation in patients with posterior urethral valves: favorable long-term outcome.

PURPOSE: We assessed the long-term efficacy of renal transplantation in patients with posterior urethral valves. MATERIALS AND METHODS: We reviewed the outcome in 23 patients with posterior urethral valves who underwent renal transplantation since 1979. RESULTS: Graft survival was 69% at 5 years and 63% at 10 years. Seven patients with followup of 7 years or longer had a mean serum creatinine level of 1.5 mg/dl. Three patients (13%) demonstrated significant bladder dysfunction postoperatively. CONCLUSIONS: Renal transplantation into a valve bladder is not associated with an abnormally high rate of failure. Deterioration of graft function secondary to lower urinary tract dysfunction is uncommon, with the majority of patients able to use the unmodified native bladder as a receptacle for the transplanted kidney.

Anterior bladder neck tube reconstruction at radical prostatectomy preserves functional urethral length--a comparative urodynamic study.

OBJECTIVE: To characterize the continence mechanism of anterior bladder neck tube reconstruction at the time of radical prostatectomy using urodynamic evaluation. PATIENTS AND METHODS: Prospective pre- and post-operative urodynamic profiles were performed in patients receiving conventional posterior 'racket handle' closures (control group--eight patients) and those receiving anterior bladder neck tube reconstruction at radical prostatectomy (study group--nine patients). Bladder neck tube reconstruction was performed by constructing 2 cm anterior bladder neck tubes over 22 F catheters. RESULTS: A significantly longer post-operative functional urethral length was demonstrated using urodynamic assessment in patients receiving an anterior bladder neck tube closure (4.6 vs 3.4 cm; P < 0.01). CONCLUSION: The anterior bladder neck tube reconstruction may promote urinary continence in patients undergoing radical prostatectomy by preservation of functional urethral length.

Penile intracavernous hematoma: diagnosis and surgical considerations.

Soft tissue lesions of the penile corporeal bodies are rare and usually represent benign or malignant tumors, or Peyronie's disease. We report a unique case of a deep seated penile mass that at exploration proved to be an encapsulated hematoma of the inter-corporeal septum. Preoperative diagnosis of lesions of the corporeal bodies is facilitated by high resolution Doppler ultrasonography. Surgical exploration to exclude malignancy must be done unless the clinical and/or radiographic findings are unequivocally benign (Peyronie's plaque, simple cyst and so forth). Surgical exploration must be done according to the penile neurovascular anatomy to preserve potency and glanular sensation.