Phosphorylation of the WH2 domain in yeast Las17/WASP regulates G-actin binding and protein function during endocytosis

Actin nucleation is the key rate limiting step in the process of actin polymerization, and tight regulation of this process is critical to ensure actin filaments form only at specific times and at defined regions of the cell. WH2 domains are short sequence motifs found in many different actin binding proteins including WASP family proteins which regulate the actin nucleating complex Arp2/3. In this study we reveal a phosphorylation site, Serine 554, within the WH2 domain of the yeast WASP homologue Las17. Both phosphorylation and a phospho-mimetic mutation reduce actin monomer binding affinity while an alanine mutation, generated to mimic the non-phosphorylated state, increases actin binding affinity. The effect of these mutations on the Las17-dependent process of endocytosis in vivo was analysed and leads us to propose that switching of Las17 phosphorylation states may allow progression through distinct phases of endocytosis from site assembly through to the final scission stage. While the study is focused on Las17, the sole WASP family protein in yeast, our results have broad implications for our understanding of how a key residue in this conserved motif can underpin the many different actin regulatory roles with which WH2 domains have been associated.

Hearing Evaluation of ARthroplasty Surgeons: results from the HEARS study

AIMS

The aim of this study was to investigate whether the prevalence of hearing loss among arthroplasty surgeons was comparable to clinicians from other medical specialties and to explore the factors associated with hearing loss.

METHODS

A cross-sectional prevalence study was carried out. Arthroplasty surgeons and non-surgical clinicians were recruited from orthopaedic and medical conferences. All participants were given a paper questionnaire including demographic details, hearing history and the Tinnitus and Hearing Survey. All participants were screened for hearing loss in a quiet room using the HearCheck Screener^™ (HCS; Siemens, Munich, Germany). Logistic regression was used to identify factors associated with hearing loss. All statistical models were adjusted for age, gender, smoking status and personal noise exposure.

RESULTS

The HEARS (Hearing Evaluation of ARthroplasty Surgeons) study recruited 188 participants (106 arthroplasty surgeons; 82 non-surgical clinicians). Prevalence of hearing loss identified by the HCS was 31% for arthroplasty surgeons vs 11% for non-surgical clinicians. The odds of failing the HCS were 3.7 times higher in arthroplasty surgeons compared to their non-surgical colleagues (p < 0.004). The odds of self-reported hearing using the Tinnitus and Hearing Survey were 2.79 times higher among arthroplasty surgeons (p < 0.003).

CONCLUSION

The prevalence of hearing loss among arthroplasty surgeons is significantly higher than in their non-surgical colleagues. Noise generated during arthroplasty surgery should be recognised and managed to create safer working conditions.

Long-Term Outcomes and Responses to Retreatment in Patients With Melanoma Treated With PD-1 Blockade

PURPOSE

To analyze long-term outcomes after treatment discontinuation of anti-programmed death-1 (anti-PD-1) therapy in a cohort of patients with melanoma with the longest follow-up yet available to our knowledge, including a majority of patients treated outside of a clinical trial. We also assessed efficacy of retreatment with anti-PD-1 therapy with or without ipilimumab in relapsing patients.

METHODS

We retrospectively analyzed all patients with nonuveal, unresectable stage III/IV melanoma treated with single-agent anti-PD-1 therapy at Memorial Sloan Kettering from 2009-2018 who had discontinued treatment and had at least 3 months of follow-up after discontinuation (n = 396). Overall survival for patients with complete response (CR) was calculated from time of CR. Time to treatment failure for patients with CR was time from CR to the next melanoma treatment or death.

RESULTS

CRs were seen in 102 of 396 patients (25.8%). The median number of months of treatment after CR was zero (range, stopped before CR to 26 months after CR). With a median follow-up of 21.1 months from time of CR in patients who did not relapse, the probability of being alive and not needing additional melanoma therapy at 3 years was 72.1%. There was no significant association between treatment duration and relapse risk. In multivariable analysis, CR was associated with M1b disease and cutaneous versus mucosal or acral primaries. Among the 78 patients (of 396) retreated after disease progression, response was seen in 5 of 34 retreated patients with single-agent anti-PD-1 therapy and 11 of 44 patients escalated to anti-PD-1 plus ipilimumab.

CONCLUSION

In our cohort, most patients discontinued treatment at the time of CR. Most CRs were durable but the probability of treatment failure was 27% at 3 years. Responses to retreatment were infrequent. The optimal duration of treatment after CR is not yet established.

Responders to anti-PD1 therapy: Long-term outcomes and responses to retreatment in melanoma (mel)

9513

Background: Little is known about patients (pts) who discontinue anti-PD1 therapy after a complete response (CR) outside of clinical trials. There are also limited data about retreatment with a second course of anti-PD1 upon disease progression. Methods: We retrospectively studied pts (n = 398) at MSKCC with unresectable mel (non-uveal) who received ≥1 dose of single-agent anti-PD1 and were followed ≥3 months (mos) after treatment cessation. CR was defined radiographically or by a negative biopsy of residual tissue. Overall survival (OS) and time to treatment failure (TTF, time until next therapy or death) were calculated from time of CR. When to stop therapy and whether to retreat after progressive disease (PD) were at the discretion of the treating oncologist. A subset of pts received a second course of single-agent anti-PD1 ≥3 months after initial discontinuation; retreated pts were evaluable if they had radiographic or clinical evaluation to assess retreatment efficacy. Results: 102 pts (25.6%) achieved CR (n = 89 radiographic, n = 13 pathologic). Median follow-up was 22.6 mos for survivors who had a CR. Estimated 3-year OS from time of CR was 82.5% (95% CI 67.4-91.0). For pts who had a CR, therapy was discontinued due to CR (n = 72), toxicity (n = 24), or other reasons (n = 6). The median duration of treatment for CR pts was 9.4 mos (range 1.6-36.1). 20 CR pts later had progressive disease (PD). Median TTF has not been reached; at 3-years the estimated treatment-free survival for CR pts was 72.3% (95% CI 60.2-81.3). 34 pts received a second course of anti-PD1 for PD after a median of 11.6 mos off treatment (range 3.5-28.6). Best responses to the second course of treatment were: 2 CRs (5.9%), 3 with tumor shrinkage (8.8%), 9 (26.5%) with SD, and 20 with PD (58.8%). Of these pts who had had a CR (n = 8) or some lesser degree of tumor shrinkage (n = 13) to the initial course of anti-PD1 treatment, only 1 and 2 pts responded, respectively, to retreatment. Median duration of retreatment was 10.9 wks. Conclusions: In this largest dataset to knowledge of mel pts treated with a second course of anti-PD1, response rate was low, even in pts who had achieved a response initially. Further study is needed into the necessary duration of initial anti-PD1 treatment and optimal strategies for initial responders who discontinue and later develop PD.

Elevated CDCP1 predicts poor patient outcome and mediates ovarian clear cell carcinoma by promoting tumor spheroid formation, cell migration and chemoresistance

Hematogenous metastases are rarely present at diagnosis of ovarian clear cell carcinoma (OCC). Instead dissemination of these tumors is characteristically via direct extension of the primary tumor into nearby organs and the spread of exfoliated tumor cells throughout the peritoneum, initially via the peritoneal fluid, and later via ascites that accumulates as a result of disruption of the lymphatic system. The molecular mechanisms orchestrating these processes are uncertain. In particular, the signaling pathways used by malignant cells to survive the stresses of anchorage-free growth in peritoneal fluid and ascites, and to colonize remote sites, are poorly defined. We demonstrate that the transmembrane glycoprotein CUB-domain-containing protein 1 (CDCP1) has important and inhibitable roles in these processes. In vitro assays indicate that CDCP1 mediates formation and survival of OCC spheroids, as well as cell migration and chemoresistance. Disruption of CDCP1 via silencing and antibody-mediated inhibition markedly reduce the ability of TOV21G OCC cells to form intraperitoneal tumors and induce accumulation of ascites in mice. Mechanistically our data suggest that CDCP1 effects are mediated via a novel mechanism of protein kinase B (Akt) activation. Immunohistochemical analysis also suggested that CDCP1 is functionally important in OCC, with its expression elevated in 90% of 198 OCC tumors and increased CDCP1 expression correlating with poor patient disease-free and overall survival. This analysis also showed that CDCP1 is largely restricted to the surface of malignant cells where it is accessible to therapeutic antibodies. Importantly, antibody-mediated blockade of CDCP1 in vivo significantly increased the anti-tumor efficacy of carboplatin, the chemotherapy most commonly used to treat OCC. In summary, our data indicate that CDCP1 is important in the progression of OCC and that targeting pathways mediated by this protein may be useful for the management of OCC, potentially in combination with chemotherapies and agents targeting the Akt pathway.

Novel PCR assay for determining the genetic sex of mice

A number of studies require the determination of the genetic sex of mouse embryos before sexual differentiation and/or of mutant mice that display partial or complete sex reversal. The majority of current methods for sexing by PCR involve multiplexing of 2 primer pairs. We have developed a novel sexing PCR using a single primer pair that amplifies fragments from the X and the Y chromosome with a clear size difference between the respective amplicons. This assay provides a rapid and reliable method to identify the genetic sex of mice across different mouse strains.

Small bowel perforation following capsule endoscopy: a case report

Small bowel perforation following a capsule endoscopy (CE) is a rare but dreadful complication. We report a CE induced small bowel perforation in a patient with Crohn's disease where preoperative investigations failed to reveal any strictures.

Prenatal exposure to vinclozolin disrupts selective aspects of the gonadotrophin-releasing hormone neuronal system of the rabbit

Developmental exposure to the agricultural fungicide vinclozolin can impair reproductive function in male rabbits and was previously found to decrease the number of immunoreactive-gonadotrophin-releasing hormone (GnRH) neurones in the region of the organum vasculosum of the lamina terminalis and rostral preoptic area by postnatal week (PNW) 6. In the present study, in an aim to further examine the disruption of GnRH neurones by foetal vinclozolin exposure, pregnant rabbits were dosed orally with vinclozolin, flutamide or carrot paste vehicle for the last 2 weeks of gestation. Offspring were euthanised at birth (males and females), PNW 6 (females), PNW 26 (adult males) or PNW 30 (adult females) of age. At birth and in adults, brains were sectioned and processed for immunoreactive GnRH. The numbers of immunoreactive GnRH neuronal perikarya were significantly decreased in vinclozolin-treated rabbits at birth and in adult littermates. By contrast, there was an increase in GnRH immunoreactivity in the terminals in the region of the median eminence. Analysis of PNW 6 female brains by radioimmunoassay revealed a two-fold increase in GnRH peptide content in the mediobasal hypothalamus in vinclozolin-treated rabbits. This finding was complemented by immunofluorescence analyses, which revealed a 2.8-fold increase in GnRH immunoreactivity in the median eminence of vinclozolin compared to vehicle-treated females at PNW 30. However, there was no difference between treatment groups in the measures of reproduction that were evaluated: ejaculation latency, conception rates or litter size. These results indicate that sub-acute, prenatal vinclozolin treatment is sufficient to create perdurable alterations in the GnRH neuronal network that forms an important input into the reproductive axis. Finally, the effect of vinclozolin on the GnRH neuronal network was not comparable to that of flutamide, suggesting that vinclozolin was not acting through anti-androgenic mechanisms.

Congenital genitourinary anomalies and sexual function

Congenital urologic abnormalities in males may contribute to sexual dysfunction seen in young men. It is the purpose of this paper to review some of the more common congenital urologic anomalies and their impact on sexual and reproductive function.

Chronic Exposure to Low Levels of Dibromoacetic Acid, a Water Disinfection By-product, Adversely Affects Reproductive Function in Male Rabbits

Four groups (minimum of 10/dose group) of male Dutch-belted rabbits were treated daily with dibromoacetic acid (DBA) via drinking water beginning in utero from gestation day 15 to adulthood; target dosages were 1, 5, and 50 mg DBA/kg body weight. Developmental, prepubertal as well as postpubertal reproductive sequelae were evaluated. One (out of 22), 2 (out of 32), and 1 (out of 21) male offspring in the 1, 5, and 50 mg DBA/kg groups were unilaterally cryptorchid. There were no significant differences in serum follicle-stimulating hormone, luteinizing hormone, and testosterone (basal concentrations or in response to exogenous gonadotropin-releasing hormone) in both prepubertal and adult rabbits. Chronic exposure to DBA adversely affected the mating abilities of some rabbits. The number of sperm produced was not affected, but spermiogenesis was disrupted, resulting in unique sperm acrosomal-nuclear malformations even at the 1-mg dose level. Concentrations of SP22, a specific sperm membrane fertility protein, in detergent extracts of ejaculated sperm were significantly lower (P < .05) in all DBA-treated groups compared with controls. The conception rates following artificial insemination of a constant number of sperm for 1, 5, and 50 mg DBA/kg groups were 55% (10/18), 65% (13/20), and 55% (9/16), respectively, vs 85% (17/20) for control group. Histologic lesions in testes characterized by spermatogenic arrest predominantly at the round spermatid stage, pyknosis of differentiating germ cells, and ultimate degeneration and desquamation leaving focal vacuolation in seminiferous epithelium were evident in DBA-treated groups. Thus, male rabbits exhibit reproductive toxicity with exposure to DBA during reproductive development at dosages as low as 1 mg/kg body weight.

Sequelae in male rabbits following developmental exposure to p,p'-DDT or a mixture of p,p'-DDT and vinclozolin: cryptorchidism, germ cell atypia, and sexual dysfunction

Rabbit does (7-9 per group) were treated daily per orum from gestation day 15 through post-natal week 4 to provide per kg body wt 25 micaromol (low) or 250 micromol (high) p,p'-DDT or a mixture of DDT and vinclozolin (12.5 and 125 micromol each). Developmental as well as post-pubertal reproductive sequelae of male progeny were studied. Testicular descent in some pups was impaired by DDT. Serum LH or testosterone was not affected. FSH was lower in mixture- but not in DDT-exposed rabbits. Lack of sexual interest, penile erection and ejaculation were observed in some mixture rabbits. Sperm counts were unaffected, but morphologically normal spermatozoa were fewer; nuclear and acrosomal morphogenesis was disrupted. Atypical germ cells resembling carcinoma in situ were found. Also considering data for vinclozolin [Veeramachaneni DNR, Palmer JS, Amann RP, Kane CM, Higuchi TT, Pau K-YF. Disruption of sexual function, FSH secretion, and spermiogenesis in rabbits following developmental exposure to vinclozolin, a fungicide. Reproduction 2006;131:805-16], we concluded that DDT causes cryptorchidism and germ cell atypia, vinclozolin permanently disrupts FSH secretion and sexual function, and the mixture causes the full spectrum of dysgenesis.

Disruption of sexual function, FSH secretion, and spermiogenesis in rabbits following developmental exposure to vinclozolin, a fungicide

We studied sequelae of prenatal plus infantile exposure of male rabbits to vinclozolin, because it is ingested by women and children. Female Dutch-Belted rabbits (7–10/group) were treated daily per orum from gestation day 15 through post-natal week 4 to provide 0, 7.2, or 72 mg vinclozolin/kg dam’s body weight/day. Vinclozolin had no effect on maintenance of pregnancy, growth of pups, age at testicular descent or weight of organs. Concentrations of serum LH or testosterone at 6, 12, or 24 weeks of age were unaffected. However, FSH was lower (P< 0.05) in both vinclozolin groups at all three ages. Following injection of GnRH at 12 or 24 weeks, the increase in FSH was less (P< 0.05) in both vinclozolin groups, as was testosterone at 12 weeks of age. After full sexual maturity, 2 of 7 low dose rabbits were uninterested in female or male teasers and never achieved erection or ejaculation. Overall, rates of ejaculation failure were: control 0% (0/48), low dose 29% (12/42), and high dose 5% (3/60). Daily sperm production per gram of testis and total number of sperm per ejaculate in both vinclozolin groups were similar (P> 0.1) to controls. However, semen from vinclozolin rabbits contained over two times more (P< 0.05) morphologically abnormal spermatozoa, mostly nuclear and acrosomal defects, than semen from controls. Seminiferous tubules with degenerative changes were more frequent (P< 0.05) in vinclozolin rabbits than in controls. Lesions included syncytia of spherical spermatids and desquamation of germ cells. Hence, developmental exposure to vinclozolin caused presumably permanent changes in copulatory ability, secretion of FSH, and spermiogenesis.

G551D CF mice display an abnormal host response and have impaired clearance of Pseudomonas lung disease

Several cystic fibrosis (CF) mouse models demonstrate an increased susceptibility to Pseudomonas aeruginosa lung infection, characterized by excessive inflammation and high rates of mortality. Here we developed a model of chronic P. aeruginosa lung disease in mice homozygous for the murine CF transmembrane conductance regulator G551D mutation that provides an excellent model for CF lung disease. After 3 days of infection with mucoid P. aeruginosa entrapped in agar beads, the G551D animals lost substantially more body weight than non-CF control animals and were less able to control the infection, harboring over 40-fold more bacteria in the lung. The airways of infected G551D animals contained altered concentrations of the inflammatory mediators tumor necrosis factor-alpha, KC/N51, and macrophage inflammatory protein-2 during the first 2 days of infection, suggesting that an ineffective inflammatory response is partly responsible for the clearance defect.

Factors influencing attachment of thermophilic bacilli to stainless steel

AIMS

This project aimed to investigate the mechanism of attachment of the vegetative cells and spores of thermophilic bacilli to stainless steel with a view to devising strategies to limit biofilm development and survival.

METHODS AND RESULTS

Spores and vegetative cells of bacterial isolates were exposed to protein denaturing agents (sodium dodecyl sulphate (SDS) and trypsin) and polysaccharide removing agents (sodium metaperiodate, trichloroacetic acid (TCA) and lysozyme). Treatment with sodium metaperiodate, TCA and lysozyme increased the number of vegetative cells attaching in many of the strains studied, while SDS and trypsin decreased attachment. Spores attached to stainless steel in greater numbers than vegetative cells, and the various treatments had less effect on this attachment than for vegetative cells. Viability of the cells or spores was not an important factor in attachment, as cells and spores rendered non-viable also attached to stainless steel in similar numbers. Coating the stainless steel with skim milk proteins decreased the attachment of both vegetative cells and spores. There was no correlation between the degree of attachment and the amount of extracellular polysaccharide (EPS) produced by each strain, surface hydrophobicity or zeta potential of vegetative cells or spores, though spores were found to be more hydrophobic than vegetative cells.

CONCLUSIONS

The results suggest that biofilm formation by these thermophilic bacilli is probably a multifactorial process, and that cell-surface proteins play a very important role in the initial process of attachment during the formation of biofilms by these bacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

This information will provide direction for developing improved cleaning systems to control biofilms of thermophilic bacilli in dairy manufacturing plants.

Long-term effects on male reproduction of early exposure to common chemical contaminants in drinking water

We evaluated sequelae to early exposure of male rabbits to drinking water containing chemicals typical of ground water near hazardous waste sites. The mixture (p.p.m. at 1x) was 7.75 arsenic, 1.75 chromium, 9.25 lead, 12.5 benzene, 3.75 chloroform, 8.5 phenol and 9.5 trichloroethylene. Dutch-Belted does received mixture at 0x (deionized water; control), 1x or 3x as drinking water from day 20 pregnancy through weaning. Exposure of individual males (7-9/treatment) continued until 15 weeks (adolescence); then, all males received deionized water. At 57-61 weeks of age, ejaculatory capability and seminal, testicular, epididymal and endocrine characteristics were evaluated. At 10 opportunities with a female teaser, all seven control males ejaculated every time, but 12 of the 17 treated males failed to express interest, achieve erection and/or ejaculate on one to five occasions; four of the 12 accomplished ejaculation with a second male teaser. Total spermatozoa/ejaculate and daily sperm production were unaffected. However, treatment caused (P < 0.03) acrosomal dysgenesis and nuclear malformations. Baseline serum concentrations of LH were lower, but with borderline significance (P = 0.05). Testosterone secretion after exogenous human chorionic gonadotrophin (P < 0.04) was low. Thus, even at 45 weeks after last exposure to drinking water pollutants, mating desire/ability, sperm quality, and Leydig cell function were subnormal.

Erectile dysfunction in patients with spina bifida is a treatable condition

PURPOSE

Now that individuals with spina bifida live well into adulthood erectile dysfunction has become a recognized associated medical disorder. To our knowledge no study has dealt specifically with treatment of erectile dysfunction in men with spina bifida. Therefore, we conducted a prospective, blinded, randomized, placebo controlled, dose escalation, crossover study to determine the ability to treat erectile dysfunction in men with spina bifida with sildenafil citrate.

MATERIALS AND METHODS

Erectile dysfunction was diagnosed in 15 men 19 to 35 years old with spina bifida who were assigned to take 4 sets of tablets, 5 tablets per set, in a random order. All patients took 25 and 50 mg. sildenafil and 2 identical looking sets of corresponding placebos 1 hour before planned sexual activity. Efficacy was assessed by the effect of treatment compared to baseline, that is before treatment, on rating of erections (scored from 0 to 10), duration of erections, frequency of erections based on response to question 1 (scored from 0 to 5) of the International Index of Erectile Function and confidence to obtain an erection based on response to question 15 (scored from 1 to 5) of the International Index of Erectile Function.

RESULTS

Improved erectile function was reported while on sildenafil by 12 (80%) men compared to baseline and placebos. There was a significant dose dependent improvement of erectile function with both 25 and 50 mg. sildenafil compared to baseline (p <0.05), as mean erectile score increased by 50% and 88%, mean duration of erections increased by 192% and 266%, mean frequency of erections increased by 61% and 96%, and mean level of confidence increased by 33% and 63%, respectively. Furthermore, 50 mg. sildenafil provided greater improvement in all 4 parameters compared to 25 mg. The placebo results were not significantly different compared to baseline for any of the parameters.

CONCLUSIONS

Erectile dysfunction in patients with spina bifida is a medically treatable condition. Sildenafil is effective in this patient population and improves level of sexual confidence.

Dizygotic twinning is not linked to variation at the alpha-inhibin locus on human chromosome 2

Natural multiple pregnancy in women leading to dizygotic (DZ) twins is familial and varies across racial groups, suggesting a genetic predisposition. Mothers of DZ twins have a higher incidence of spontaneous multiple ovulation and elevated FSH concentrations. FSH release is controlled by feedback of inhibin peptides from the ovary, and immunization against inhibin alpha-subunit results in an increased ovulation rate in animals. The inhibin alpha-subunit is therefore a candidate gene for mutations that may increase the frequency of DZ twinning. Restriction digests of a PCR product from exon 1 with the enzyme SpeI detects a C/T polymorphism at bp 128 with two alleles of 447 and 323/124 bp. The polymorphism was typed in 1,125 individuals from 326 pedigrees with 717 mothers of spontaneous DZ twins. The alpha-inhibin locus mapped within 3 centimorgans of D2S164, and linkage with DZ twinning was excluded [decimal log odds ratio (LOD) score, -2.81 at theta = 0]. There was complete exclusion of linkage (LOD, less than -2) of a gene conferring relative risk 1.8 (lambdas, >1.8) across the chromosome, except at the p-terminus region and a small peak (maximum LOD score, 0.6) in the region of D2S151-D2S326. Analysis using either recessive or dominant models excluded linkage with DZ twinning in this population (LOD score, less than -2.5) across chromosome 2. We conclude that dizygotic twinning is not linked to variation in the alpha-inhibin locus. The results also suggest that mutations in other candidates on chromosome 2, including the receptor for FSH and the betaB-inhibin subunit (INHBB) cannot be major contributors to risk for DZ twinning.

Erectile dysfunction in spina bifida is treatable

We undertook a prospective, blinded, randomised, placebo-controlled, dose escalation, crossover study that showed that erectile dysfunction in spina bifida is medically treatable, specifically with sildenafil citrate.

Duplicated seminal vesicle

We report a case of complete, unilateral seminal vesicle duplication without concomitant reproductive duct or renal anomalies encountered during radical retropubic prostatectomy. We also discuss the possible embryologic origin of this anomaly and the clinical implications.

Prioritization in community health planning: combining methods to achieve implementable priorities

Community Health Planning (CHP) is one of the tools that states and localities use to develop health policies and programs. The author argues that, for CHP to succeed, it must include both positive/hierarchic data as well as interpretive information. To augment the discussion, the author discusses the State of Tennessee's effort to revamp its public health mission and strategies as specifically implemented in one county. The author contrasts the two types of data generated and argues that each has a legitimate claim in the CHP process: the "positive" data in the form of epidemiological statistics to inform the stakeholders and the "interpretive data" in the form of stakeholder participation for ownership of the process. The author then draws implications for states and localities to use diverse information sources as they improve services and service delivery to citizens and recipients.

Possible mechanisms for epididymal sparing during testicular ischemia

OBJECTIVES

Although extensive research has been conducted on the normal anatomy and physiology of the epididymis, the effects of ischemia on the organ have not been primarily investigated. The aim of the present study was to investigate the macroscopic and microscopic effects of prolonged ischemia on the epididymis and the factors that may contribute to its resistance to ischemia.

METHODS

Six groups of male Sprague-Dawley rats (6 rats/group) were studied. Groups 1, 2, and 3 underwent a sham operation of 4, 8, and 12 hours, respectively, and groups 4, 5, and 6 underwent 4, 8, and 12 hours of ischemia, respectively. The ipsilateral testes and epididymides were monitored throughout the experiment. At the conclusion of the experiment, bilateral orchiectomy was performed, and structures were histologically evaluated.

RESULTS

There were no abnormal macroscopic findings of the bilateral epididymides of groups 1, 2, and 3 or of the contralateral, control epididymides of groups 4, 5, and 6. Macroscopically, there was a direct correlation between the length of ischemia and the degree of hemorrhagic discoloration of the proximal caput. The degree of hemorrhagic infiltration noted microscopically was consistent with the macroscopic observations. The epithelia of the ischemic epididymides remained intact with numerous microvilli.

CONCLUSIONS

The results of this study suggest that the epithelium of the epididymis is relatively resistant to ischemic damage compared with the gonad during testicular ischemia.

Surfactant administration reduces testicular ischemia-reperfusion injury

PURPOSE

The mechanism of testicular ischemia-reperfusion injury has not been well delineated. We determined the efficacy of a biocompatible surfactant (tetronic 1107) to reduce tissue injury and evaluated cell membrane integrity as reflected by calcium ion permeability in an in vivo animal model of testicular ischemia-reperfusion.

MATERIALS AND METHODS

Three groups of male Sprague-Dawley rats (6 per group) were studied. Group 1 was the nonoperative control, and groups 2 and 3 underwent 4 hours of unilateral testicular ischemia followed by 4 hours of reperfusion. Ten minutes after reperfusion 0.4 ml. saline was administered intravenously to group 2 and 180 mg./kg. surfactant tetronic 1107 to group 3. 99mTechnetium pyrophosphate was used to monitor calcium ion uptake by the ipsilateral and contralateral testicles. Both testicles were also examined histologically.

RESULTS

The surfactant treated animals had markedly diminished hemorrhagic discoloration and vascular congestion compared to saline treated animals. These results were confirmed microscopically with improved nuclear chromicity and disarray of germ cell layers of the seminiferous tubules. The surfactant treated group also had a statistically significant (p <0.05) reduction in radiotracer uptake compared to the saline treated animals, confirming a reduction in calcium ion permeability.

CONCLUSIONS

The results of this study suggest that tetronic 1107 is effective in reducing tissue damage in a testicular ischemia-reperfusion animal model.

Comparison of blood flow and histological changes in rat models of testicular ischemia

PURPOSE

Our aim was to quantify objectively the degree of vascular insufficiency produced by twisting versus clamping the spermatic cord, and determine the contribution of the vasal vessels to these changes using the laser Doppler flowmeter.

MATERIALS AND METHODS

Three groups of 12 male Sprague-Dawley rats each were studied. Group 1 underwent 720-degree torsion of the spermatic cord, group 2 underwent vascular clamping of the spermatic cord with 1 clamp, excluding the anatomically separate vasal vessels, and group 3 underwent vascular clamping of the entire spermatic cord and vasal vessels with 2 clamps. Blood flow and histological changes were determined.

RESULTS

Vascular clamping of the spermatic cord in groups 2 and 3 resulted in a significant decrease in testicular blood flow compared to 720-degree torsion (p < 0.05). These flow changes correlated with more severe and reproducible gross changes, and histological features of seminiferous tubule degeneration compared to spermatic cord twisting.

CONCLUSIONS

In the rat clamping the spermatic cord is a more severe and reproducible model of testicular torsion than 720-degree torsion. The contribution of the vasal vessels to the decrease in blood flow and resulting histological degeneration after testicular ischemia is negligible in the rat.

A platelet activating factor antagonist attenuates the effects of testicular ischemia

PURPOSE

Platelet activating factor, a biochemical marker and lipid mediator of ischemic injury, has been demonstrated in several organ systems. The objective of this study was to investigate the possible role of platelet activating factor in testicular ischemic injury.

MATERIALS AND METHODS

Five groups of 6 male Sprague-Dawley rats were studied, including group 1-nonoperated controls, group 2-sham operated controls, group 3-those that underwent administration of 10 micrograms./kg. exogenous platelet activating factor into the left testicular artery, group 4-those that underwent 4 hours of testicular ischemia and group 5-those that received pretreatment with 0.4 mg./kg. of the platelet activating factor antagonist CV-6209 intravenously before 4 hours of testicular ischemia. Ipsilateral and contralateral testes were examined histologically and seminiferous tubular diameters were measured.

RESULTS

Exogenous platelet activating factor administration in group 3 and 4 hours of ischemia in group 4 resulted in a similar extent of histological degeneration of the experimental testicle. Pretreatment with CV-6209 in group 5 resulted in a marked decrease in hemorrhagic discoloration, vascular congestion and histological changes noted with ischemia in group 4.

CONCLUSIONS

The results of this study suggest that platelet activating factor has a biochemical role in tissue injury associated with testicular ischemia. Also, administration of a platelet activating factor antagonist before the ischemic event decreases seminiferous tubule degeneration.

Benchmarking the perioperative process. I. Patient routing systems: a method for continual improvement of patient flow and resource utilization

The article presents an overview of the design and application of a real-time patient routing system, based on barcode and local area network technology, that was designed to track the progress of patients during the perioperative process. We present data on all patients undergoing ambulatory surgery. Patients' progress during their surgical stay was recorded at 17 strategic events using this real-time patient tracking technology. These times were used to identify inefficiencies in the perioperative process by identifying bottlenecks and areas of high variation. We found that both raw and actual operating room (OR) utilization efficiency was less than 50%. Points of high variation in a patient's progress occurred during the time from admit to the hospital until the patient was ready for the OR; the time from when a patient was ready for the OR until they were called for; and the time a patient spends in the OR preoperative holding room. Causes for variation were identified and traced back to individual procedures, activities, and work processes. Multidisciplinary improvement teams were created to improve the pinpointed problem areas. The real-time patient routing system is a process that has proven to be highly valuable to all participants in the surgical process in bringing about rational, data driven efficiencies in perioperative services. This process has the potential to facilitate multidisciplinary cooperation in efforts to contain and reduce costs of perioperative services.

Defining the role of surveillance in the management of localized prostate cancer

With the dramatic increase in the detection of prostate cancer in the last 5 years, there has been an enormous challenge for physicians to recommend the "best" therapy for patients with localized prostate cancer. This challenge, however, has been difficult to meet because of the absence of well-conducted comparative trials. Because the primary goal of the urologist has been to "cure" prostate cancer and prolong life, the concept of surveillance therapy seems to be quite inappropriate; however, few other diseases have treatments that can so negatively impact on a man's daily quality of life. In addition, the natural history of this cancer, in contrast to many others, does not invariably lead to metastasis or death during the normal life span of most patients. Therefore, in contrast to physicians, many men may wish to maximize their quality of life rather than their duration of survival. This choice depends on the probability of good and bad outcomes that are possible with each treatment option. Ultimately, it is the patient's choice to make with help and unbiased guidance from the physician.

Same day surgery for radical retropubic prostatectomy: is it an attainable goal?

OBJECTIVES

Economic forces are stimulating a re-evaluation of various management strategies. Recent critical pathways for radical prostatectomy have resulted in reduced length of stay to as low as 2.9 days.

METHODS

The time in the operating room and recovery room, average blood loss, length of hospitalization, patient charges, and estimated hospital costs were compared for 20 patients undergoing radical prostatectomy up to 1 year before and for 27 men after initiation of a critical pathway. Under the protocol, patients receive an education booklet and preoperative teaching in preparation for early discharge and an epidural for anesthesia. An anonymous questionnaire was mailed to all patients treated by the pathway after catheter removal.

RESULTS

The new pathway resulted in a significant reduction in average time in the operating room (3.7 +/- 0.4 hours versus 4.9 +/- 1.2 hours), estimated blood loss (1204 +/- 527 cc versus 1948 +/- 740 cc), and length of hospitalization (1.7 +/- 0.6 days versus 4.6 +/- 1.5 days). In addition, patient charges and hospital costs were reduced by 32% and 35%, respectively. Thirty-seven percent of the study group was discharged after 1 night compared with 0% in the group treated before the pathway was initiated. Forty-one percent of the study group was not transfused and did not donate blood. Outcome surveys completed by 25 of 27 study patients revealed an overall satisfaction of 96% with 0 of 10 patients who were discharged after one night indicating they would have preferred to be hospitalized longer.

CONCLUSIONS

Conventional management of men undergoing radical prostatectomy can be safely modified while preserving patient satisfaction without increasing morbidity. Avoiding peripheral narcotics and emphasizing preoperative teaching has enabled us to reduce length of stay greatly, with same day discharge now an attainable goal.

Toward a unified theory of sexual mixing and pair formation

Sexually transmitted diseases such as gonorrhea, syphilis, herpes, and AIDS are driven and maintained in populations by epidemiological and sociological factors that are not completely understood. One such factor is the way in which people mix sexually. In this paper, we outline a unified approach to modeling sexual mixing structures, where such structures are defined in terms of a set of axioms for a finite number of distinct groups of people. Theorems for homosexual, heterosexual, and arbitrary group mixing are presented, leading to a representation of all mixing structures defined by the axioms. The representation and its parameters are interpreted in terms of intergroup affinities for sexual mixing. The use of the approach in sexually transmitted disease modeling is discussed.

Cooperativity in axonemal motion: analysis of a four-state, two-site kinetic model

A kinetic model for axonemal motion based upon a four-state mechanochemical cycle of dynein with two active sites is described. Our model analysis determines the pseudo-steady-state concentrations of enzyme species for specified rate constants, most of which are experimentally determined, with given substrate and product concentrations. The proportion of enzyme species in which both active sites are detached from the microtubule (denoted as "both detached"), numerically calculated from the model, appears to be proportional to experimental observations of flagellar beat frequency. This correlation between beat frequency and the both-detached enzyme species is maintained over a wide range of substrate concentrations and exhibited an apparent positive cooperativity at low substrate concentrations, which we call "obligate cooperativity." The unusual obligate cooperativity exhibited by flagellar beat frequency parallels that seen in the calculated proportion of the both-detached enzyme species and is interpreted as a requirement for a molecule of substrate to bind to each active site in a multimeric dynein in order to produce oscillatory motion. Furthermore, the proportion of the both-detached enzyme species correlates with experimentally observed changes in beat frequency with a nucleotide analog and with product inhibition.

Medroxyprogesterone, immunosuppression, and conceptus size in Peromyscus

Effects of exogenous medroxyprogesterone acetate (MPA) on skin transplant retention and conceptus size were studied in the deer mouse, Peromyscus maniculatus, and the oldfield mouse Peromyscus polionotus. Daily injections of 2 mg MPA significantly prolonged survival of allografts in P. maniculatus and transspecific grafts between P. maniculatus and P. polionotus. Allografts were retained significantly longer than transspecific grafts (17.2 vs 12.4 days) on MPA-treated P. maniculatus. Near-term fetal and placental sizes and weights were not detectably influenced by daily 1-mg MPA injections given to the mother from the 5th through the 19th day of pregnancy. The data are discussed relative to the possible immunosuppressive role of progestins in protecting the allogeneic conceptus from maternal immune rejection.

Toxicologic evaluation of diisopropyl methylphosphonate and dicyclopentadiene in cattle

Diisopropyl methylphosphonate (DIMP), and dicyclopentadiene [3a,4,7,7a-tetrahydro-4,7-methyanoindene] (DCPD), were found as contaminants of groundwater in Colorado. Since there was a potential for cattle to be exposed to these chemicals by drinking well water, a study of their effects was initiated. Eight-to-ten week old calves were given a single dose of either DIMP at 62.5, 125, 250, 500 and 1000 mg/kg of body weight (b.w.) or DCPD at 250, 500, 1000 or 2000 mg/kg of b.w. The calves given DIMP developed tympanitis and ataxia, followed by depression, prostration, and death within two hr after dosing. A slight but significant increase in activated partial thromboplastin time was the only change observed in any of the clinical pathologic parameters. The only gross pathologic changes were acute gastroenteritis with hemorrhages in calves given 1000 mg/kg of b.w. Mild signs of intoxication, ataxia and excess salivation, were observed in calves given 250 mg of DCPD/kg of b.w. At higher doses, these signs were intensified; in addition, calves fell and, while prostrate, exhibited running movements and tonic, clonic spasms. The severity of the signs observed increased as the dose of DCPD increased. All calves given 2000 mg/kg of b.w. and one calf given 1000 mg/kg of b.w. died before seven days after dosing. The only clinical pathologic changes found were increased serum levels of creating phosphokinase, glutamic-oxalacetic transaminase, and glutamic pyruvic transaminase. The only consistent gross pathologic change was congestion in a variety of tissues in calves given 2000 mg/kg of b.w. A variety of histologic changes were observed in tissues from calves treated with both chemicals. However, these changes were not consistent for any one dose level and were not dose dependent. DIMP was slightly toxic for calves, since no signs of intoxication were observed at doses less than 1000 mg/kg of b.w. DCPD exerted detrimental effects on calves at 250 mg/kg of b.w. and was classified as moderately toxic.

Effect of age on tolerance of calves to chlorpyrifos

Groups of five calves (1 to 2 weeks old) or older calves (4 to 6 months old) were treated topically with increasing concentrations of chlorpyrifos [O,O-diethyl-O(-3,5,6-trichloro-2-pyridinyl) phosphorothioate] to determine their susceptibility to chlorpyrifos toxicity. Newborn calves also were given oral doses of technical grade (97.4%) chlorpyrifos to estimate their susceptibility by this treatment route. Topical applications to newborn calves consisted of 0.02%, 0.06%, or 0.12% chlorpyrifos administered as a spray to the entire body surface. Oral dosages given the newborn calves consisted of 5, 10, or 25 mg of chlorpyrifos/kg of body weight. Topical applications were administered to the older calves in the same manner as were applications to the newborn calves, but at concentrations of 0.25%, 0.5%, 0.9%, or 2.3%. Minimum dosages producing signs of toxicosis in newborn calves which were orally and topically given chlorpyrifos were 25 mg/kg of body weight and 0.06%, respectively. All five newborn calves sprayed with 0.12% chlorpyrifos were severely poisoned and were treated with atropine. One of these calves died within 48 hours after exposure to chlorpyrifos despite antidotal therapy. Signs of poisoning were not observed in older calves sprayed with 0.25%, 0.5%, or 0.9% chlorpyrifos. One Brahman-cross calf sprayed with 2.3% chlorpyrifos developed signs of mild poisoning that dissipated in 72 hours without treatment. Four older non-Brahman calves sprayed with 2.3% chlorpyrifos did not show signs of poisoning. Seemingly, 4- to 6-month old calves have an increased tolerance to topically applied chlorpyrifos compared with the tolerance of newborn calves, and the magnitude of this increased tolerance is 30-fold or higher.

Comparison of two procedures for determination of cholinesterase in livestock

Our data indicate that the serum or plasma Bio-Dynamics/bmc automated procedure may be substituted satisfactorily for, or used as an alternative method to the Radeleff procedure for determining cholinesterase activity in cattle, swine, and sheep. The automated procedure is capable of 77 determinations/hr, and the Radeleff procedures about 20/hr. Either serum or plasma may be used, but the sample must be hemolyzed.

Toxicologic evaluation of microencapsulated formulation of diazinon applied dermally to cattle

Acute toxicity studies in 24 newborn calves and 12 two-year-old steers were conducted with a microencapsulated formulation of diazinon (O-O-diethyl O-(2-isopropyl-6-methyl-4-yrimidinyl) phosphorioate) after dermal applications. For calves, the maximum safe dosages of a diazinon wettable powder formulation were identical with those of the new formulation (0.05% concentration); for older cattle, safe dosages were 0.25% concentration. Thus, because of the slow release and absorption of diazinon, the safety factor for mature cattle is fourfold. In the present study, there was cholinesterase depression in calves at the toxic concentrations of 0.1% and in steers at concentrations of 2.0%. As determined by the mean cholinesterase depression activity, the dose-response relationship was true in the 4 treatment groups of older cattle, but was erratic in the 6 groups of calves. The use of modified and improved insecticidal formulations, such as the encapsulated type, is recommended. Their use may prolong acaracidal activity due to effective residues, eliminate the need for repeated applications at shorter intervals of time, and possibly allow increased dosages to mature cattle, without toxicity, and thus reduce acquired resistance of ticks and other insects.

Toxicologic evaluation of a microencapsulated formulation of methyl parathion applied dermally to cattle

Acute toxicity studies in newborn calves and 2- to 3-year-old cattle were conducted with methyl parathion (O,O-dimethyl O-(p-nitrophenyl) phosphorothioate) in the form of a 22% microencapsulated slurry used in a manually operated sprayer. Twelve calves and 9 cattle were tested. The minimal toxic dosages were 4 L of a 0.5% concentration for calves and 10 L of a 0.25% concentration for mature cattle. At all toxic dosages, cholinesterase activities were decreased--that of the calves to 0 and that of the cattle to 50% of base line or less. Weight losses 2 weeks after single exposures to the treated cattle ranged from 6.5% to 11.5% of total body weight. Absorption of the formulation in its entirety or its metabolic products resulted in a possible interference with feed utilization.

Beta-adrenergic receptor: stereospecific interaction of iodinated beta-blocking agent with high affinity site

An iodine-labeled beta-adrenergic inhibitor ((125)l-hydroxybenzylpindolol) binds specifically to a site on turkey erythrocyte membranes. A series of beta-adrenergic agonists and inhibitors compete for this binding site, with apparent affinities paralleling biological effectiveness as activators or inhibitors of catecholaminestimulated adenylate cyclase. The activity of d-(+) agonists or inhibitors was 1 percent (or less) than that of the corresponding l-(-) isomers in competing for binding of the iodinated blocker as well as in affecting catecholamine-stimulated adenylate cyclase. 1-(-)-Norepinephrine was about one-tenth as active as l-(-)-isoproterenol in competing for the beta-blocking agent site. The stereospecificity of the interaction with the iodinated beta-blocking agent and the correspondence between affinity for site and biological potency of analogs suggested that this interaction is involved in function of the beta-adrenergic receptor.