Evaluating broiler welfare and behavior as affected by growth rate and stocking density

This study evaluated the welfare and behaviors of Cobb 700 broilers as affected by growth rate (GR) and stocking density (SD). Slower-growth (weight gain < 50 g/d) and medium-growth (weight gain = 50-60 g/d) broilers were produced by providing 57.1% and 78.6% of the feed intake listed in the Cobb 700 production manual for standard (fed ad libitum) broilers (weight gain > 60 g/d). Broilers at all 3 GRs were reared at 2 SDs of 30 and 40 kg/m2. Broiler welfare indicators, including gait score, tibia strength, feather coverage, and footpad condition were evaluated when birds reached 1, 2, and 3 kg of body weight. The activity index was determined by overhead cameras and image processing, and the time spent at feeders was recorded using the radio-frequency identification (RFID) systems. The results show that it took 45 d for standard, 52 d for medium-growth, and 62 d for slower-growth broilers to reach a 3 kg market body weight. Feed conversion ratios (FCR, kg/kg) were 1.57 for standard, 1.67 for medium-growth, and 1.80 for slower-growth broilers. Growth rate and SD had an interaction effect on feather cleanliness (P = 0.03), and belly feather coverage (P = 0.02). Slower-growth broilers were more active and had better feather coverage and gait scores than medium-growth and standard broilers (all P < 0.01) but may feel hungry and depressed, medium-growth broilers spent the most time at the feeder among the 3 growth groups (P = 0.02), and standard broilers showed the best production performance. Broilers at 30 kg/m2 showed better bone strength (P = 0.04), and footpad condition (P < 0.01) compared to those at 40 kg/m2. In conclusion, reducing GR and SD may slightly improve broiler leg health at the high expense of compromised production performance and prolonged production cycles.

Multiorgan MRI findings after hospitalisation with COVID-19 in the UK (C-MORE): a prospective, multicentre, observational cohort study

INTRODUCTION

The multiorgan impact of moderate to severe coronavirus infections in the post-acute phase is still poorly understood. We aimed to evaluate the excess burden of multiorgan abnormalities after hospitalisation with COVID-19, evaluate their determinants, and explore associations with patient-related outcome measures.

METHODS

In a prospective, UK-wide, multicentre MRI follow-up study (C-MORE), adults (aged ≥18 years) discharged from hospital following COVID-19 who were included in Tier 2 of the Post-hospitalisation COVID-19 study (PHOSP-COVID) and contemporary controls with no evidence of previous COVID-19 (SARS-CoV-2 nucleocapsid antibody negative) underwent multiorgan MRI (lungs, heart, brain, liver, and kidneys) with quantitative and qualitative assessment of images and clinical adjudication when relevant. Individuals with end-stage renal failure or contraindications to MRI were excluded. Participants also underwent detailed recording of symptoms, and physiological and biochemical tests. The primary outcome was the excess burden of multiorgan abnormalities (two or more organs) relative to controls, with further adjustments for potential confounders. The C-MORE study is ongoing and is registered with ClinicalTrials.gov, NCT04510025.

FINDINGS

Of 2710 participants in Tier 2 of PHOSP-COVID, 531 were recruited across 13 UK-wide C-MORE sites. After exclusions, 259 C-MORE patients (mean age 57 years [SD 12]; 158 [61%] male and 101 [39%] female) who were discharged from hospital with PCR-confirmed or clinically diagnosed COVID-19 between March 1, 2020, and Nov 1, 2021, and 52 non-COVID-19 controls from the community (mean age 49 years [SD 14]; 30 [58%] male and 22 [42%] female) were included in the analysis. Patients were assessed at a median of 5·0 months (IQR 4·2-6·3) after hospital discharge. Compared with non-COVID-19 controls, patients were older, living with more obesity, and had more comorbidities. Multiorgan abnormalities on MRI were more frequent in patients than in controls (157 [61%] of 259 vs 14 [27%] of 52; p<0·0001) and independently associated with COVID-19 status (odds ratio [OR] 2·9 [95% CI 1·5-5·8]; padjusted=0·0023) after adjusting for relevant confounders. Compared with controls, patients were more likely to have MRI evidence of lung abnormalities (p=0·0001; parenchymal abnormalities), brain abnormalities (p<0·0001; more white matter hyperintensities and regional brain volume reduction), and kidney abnormalities (p=0·014; lower medullary T1 and loss of corticomedullary differentiation), whereas cardiac and liver MRI abnormalities were similar between patients and controls. Patients with multiorgan abnormalities were older (difference in mean age 7 years [95% CI 4-10]; mean age of 59·8 years [SD 11·7] with multiorgan abnormalities vs mean age of 52·8 years [11·9] without multiorgan abnormalities; p<0·0001), more likely to have three or more comorbidities (OR 2·47 [1·32-4·82]; padjusted=0·0059), and more likely to have a more severe acute infection (acute CRP >5mg/L, OR 3·55 [1·23-11·88]; padjusted=0·025) than those without multiorgan abnormalities. Presence of lung MRI abnormalities was associated with a two-fold higher risk of chest tightness, and multiorgan MRI abnormalities were associated with severe and very severe persistent physical and mental health impairment (PHOSP-COVID symptom clusters) after hospitalisation.

INTERPRETATION

After hospitalisation for COVID-19, people are at risk of multiorgan abnormalities in the medium term. Our findings emphasise the need for proactive multidisciplinary care pathways, with the potential for imaging to guide surveillance frequency and therapeutic stratification.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Is Retention of the Acetabular Component at Revision Surgery a Long-Term Solution?

Background

Acetabular retention in revision total hip arthroplasty (THA) may be advantageous, yet long-term survival data is limited. Thus, we investigated long-term survivorship of retained acetabular components in revision THA with analysis of rerevision rate, instability risk, and clinical outcomes.

Methods

We reviewed 98 hips with polyethylene wear and/or osteolysis that were revised with retained acetabular components. Acetabular inclination and anteversion were measured from prerevision radiographs. A retrospective chart review was performed, collecting outcomes of interest including Harris hip score, instability events, and rerevision surgery. Kaplan-Meier analysis was used to calculate the risk of revision over time. Predictors of survival including acetabular component position were analyzed by multiple logistic regression.

Results

Average follow-up was 13 years (range, 5-24). Survivorship rates at 5, 10, 15, and 20 years were 89.7%, 81.6%, 70.8%, and 63.8%, respectively. There was improvement in average Harris hip score (61 to 76, P < .0001). There was a 9% rate of dislocation, and 6 hips (6%) were rerevised for recurrent instability. Overall, there were 23 (23%) rerevisions at an average of 6.1 years with the most common reasons being instability (6%) and aseptic loosening (6%). Use of conventional polyethylene was the only identified independent predictor of rerevision (P = .025).

Conclusions

Retention of a well-fixed acetabular component in revision THA provides acceptable long-term outcomes with a 15-year survivorship of 71%. Instability and aseptic loosening were the most common reasons for rerevision. Surgeons may consider retaining the acetabular component at revision surgery if the implant is well-fixed and well-positioned.

Mean 16-Year Results of Total Hip Arthroplasty with Alumina Ceramic Femoral Heads on Highly Cross-Linked Polyethylene in Patients 50 Years or Less

BACKGROUND

Highly cross-linked polyethylene (HXLPE) is a widely used bearing surface in total hip arthroplasty (THA); long-term results in young patients are limited. We previously demonstrated excellent results in HXPLE on cobalt-chrome femoral heads at 15-year mean follow-up. The purpose of the present study was to investigate polyethylene wear rates, implant survivorships, wear-related revisions, and patient-reported outcomes (PROs) in a young patient cohort who had alumina ceramic on HXPLE coupling at an average 16-year follow-up.

METHODS

This was a retrospective study of 128 hips who underwent THA with HXLPE on alumina ceramic bearings between March 1, 2004, and April 15, 2007. Patient mean age was 38 years (range, 13 to 50). All THAs utilized HXPLE liners with alumina ceramic heads. The University of California, Los Angeles (UCLA) Activity Score and modified Harris Hip Scores (mHHS) were collected pre-operatively and at each follow-up. Martell Hip Analysis Suite was used for wear calculations.

RESULTS

At average 16 years (range, 13 to 18), aseptic revision survivorship was 93.3% and osteolysis/wear survivorship was 99.2%. The mean linear wear rate was 0.0191 millimeters (mm)/year and mean volumetric wear rate was 19.43 mm³/year, both of which were clinically undetectable. We observed excellent patient reported outcomes with a significant increase in mean mHHS (43.6 to 87.4, P <0.0001) and UCLA Activity Scores (4.0 to 6.0, P <0.0001). There were no statistically significant differences in PROs or wear rates between ceramic and cobalt-chrome groups.

CONCLUSION

At mean 16-year follow-up, young patients who had HXLPE on ceramic coupling had excellent wear properties, PROs, and acceptable survivorships.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Combined Surgical Dislocation and Periacetabular Osteotomy for Complex Residual Legg-Calvé-Perthes Deformities: Intermediate-Term Outcomes

BACKGROUND

Residual Legg-Calvé-Perthes (LCP) deformities represent one of the most challenging disorders in hip reconstructive surgery. In complex cases, both instability (acetabular dysplasia) and multifocal femoroacetabular impingement (FAI) (proximal femoral deformities) require correction. We assessed intermediate-term patient-reported outcome measures, radiographic correction, complications, and survivorship for combined surgical dislocation (SD) and periacetabular osteotomy (PAO) for the treatment of complex LCP deformities.

METHODS

A retrospective cohort study was performed on 31 hips with complex LCP deformities undergoing combined SD and PAO for concurrent instability and FAI. Treatment included femoral head reshaping, trochanteric advancement and relative femoral neck lengthening, management of intra-articular lesions, and PAO. Twenty-seven hips (87%) had a minimum follow-up of 5 years. The mean age was 19.8 years, 56% of patients were female, and 44% of patients had undergone a previous surgical procedure.

RESULTS

At a mean of 8.4 years, 85% of hips (23 of 27) remained preserved (no conversion to total hip arthroplasty). The survivorship estimates were 93% at 5 years and 85% at 10 years. The median (and interquartile range) increased from 64 points (55, 67 points) to 92 points (70, 97 points) (p < 0.001) for the modified Harris hip score (mHHS) and from 60 points (45, 75 points) to 86 points (75, 100 points) (p = 0.001) for the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score. Symptoms (mHHS < 70 points) were reported for an additional 19% of hips (n = 5) at the final follow-up. The University of California Los Angeles (UCLA) activity score increased from a median of 8 points (6, 10 points) to 9 points (7, 10 points) (p = 0.207). Structural correction included mean improvement (and standard deviation) of 15.3° ± 7.6° for acetabular inclination, 20.7° ± 10.8° for the lateral center-edge angle, 23.4° ± 16.3° for the anterior center-edge angle, and 18 ± 10 mm for trochanteric height (p < 0.001 for all). Complications occurred in 2 hips (7%), including 1 deep wound infection and 1 superficial wound infection. There was 1 reoperation due to complication, but there were no nerve palsies, thromboembolic events, fractures, or nonunions.

CONCLUSIONS

At an intermediate follow-up of combined SD and PAO for complex LCP deformities, 85% of hips were preserved. This procedure provides reliable deformity correction, major pain relief, improved function, and acceptable complication and failure rates.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

1006 Sleep Problems and Risk of Cancer Incidence and Mortality in the Cardiovascular Health Study (CHS)

Introduction

Even in the absence of a formal diagnosis, sleep problems (SP) are frequently indicative of an underlying sleep disorder, such as obstructive sleep apnea, which may be adversely associated with cancer risk and cancer outcomes.

Methods

We assessed the association of self-reported SP with incident cancer (N=4,997, excluding prevalent cancers) and cancer mortality (N=5849) among the participants of Cardiovascular Health Study (CHS), a population-based study of adults aged &gt;=65 years recruited from 4 US communities. Participants reported SP (daytime sleepiness, observed apnea and snoring) yearly from 1989-1994; these self-reported symptoms have been validated against objective sleep measures assessed within a subset of CHS participants (n= 1240) who received a home polysomnography as part of the Sleep Heart Health Study. Cancer incidence was ascertained through linkage with state cancer registries through 2005; cancer specific death was adjudicated through 2015. We used Cox proportional hazards regression to calculate hazard ratios (HR) and 95% confidence intervals (CI) for associations of baseline SP with subsequent cancer incidence and cancer mortality, adjusting for baseline sociodemographics, lifestyle factors, and medical history.

Results

The mean age (SD) of the study population was 73 (6) years, 56% were female, and 84% were white. The prevalence of SP was 17% for daytime sleepiness, 8% for observed apnea, and 24% for snoring; 63% reported none of the 3 SP. Overall, 1,130 first incident cancers and 1,014 cancer deaths were identified over median follow-up of 12 and 13 years, respectively. Compared to participants who reported no SP, the risk of incident cancer was inversely associated with daytime sleepiness (HR 0.86 [95% CI 0.70-1.04]), observed apnea (HR 0.74 [0.56-1.00]), and snoring (HR 0.80 [0.68-0.95]). Cancer mortality HR (95% CI) estimates were 1.00 (0.82-1.21) for daytime sleepiness, 0.77 (0.57-1.04) for observed apnea, and 0.88 (0.74, 1.04) for snoring.

Conclusion

Symptoms indicating SP reported at baseline were not associated with increased cancer incidence or cancer mortality. Ongoing analyses are focused on the impact of longitudinal SP (time dependent, cumulative average) to ensure an adequate latency period is incorporated into our analysis of the association between SP and cancer risk and mortality.

Support

NIHT32CA09488017

Myeloid-derived suppressor cell-like fibrocytes are increased and associated with preserved lung function in chronic obstructive pulmonary disease

BACKGROUND

The role of fibrocytes in chronic obstructive pulmonary disease (COPD) is unknown. We sought to enumerate blood and tissue fibrocytes in COPD and determine the association of blood fibrocytes with clinical features of disease.

METHODS

Utilizing flow cytometry to identify circulating, collagen type 1⁺ cells, we found two populations: (i) CD45⁺ CD34⁺ (fibrocytes) and (ii) CD45⁺ CD34^- [myeloid-derived suppressor cell (MDSC)-like fibrocytes] cells in stable COPD (n = 41) and control (n = 29) subjects. Lung resection material from a separate group of subjects with (n = 11) or without (n = 11) COPD was collected for tissue fibrocyte detection. We examined circulating fibrocyte populations for correlations with clinical parameters including quantitative computed tomography (qCT) and determined pathways of association between correlated variables using a path analysis model.

RESULTS

Blood and tissue fibrocytes were not increased compared to control subjects nor were blood fibrocytes associated with lung function or qCT, but were increased in eosinophilic COPD. Myeloid-derived suppressor cell-like fibrocytes were increased in COPD compared to controls [2.3 (1.1-4.9), P = 0.038]. Our path analysis model showed that collagen type 1 intensity for MDSC-like fibrocytes was positively associated with lung function through associations with air trapping, predominately in the upper lobes.

CONCLUSION

We have demonstrated that two circulating populations of fibrocyte exist in COPD, with distinct clinical associations, but are not prevalent in proximal or small airway tissue. Blood MDSC-like fibrocytes, however, are increased and associated with preserved lung function through a small airway-dependent mechanism in COPD.

Language, games and the role of interpreters in psychiatric diagnosis: a Wittgensteinian thought experiment

British society is becoming increasingly culturally and linguistically diverse. This poses a major challenge to mental health services charged with the responsibility to work in ways that respect cultural and linguistic difference. In this paper we investigate the problems of interpretation in the diagnosis of depression using a thought experiment to demonstrate important features of language-games, an idea introduced by Ludwig Wittgenstein in his late work, Philosophical investigations. The thought experiment draws attention to the importance of culture and contexts in understanding the meaning of particular utterances. This has implications not only for how we understand the role of interpreters in clinical settings, and who might best be suited to function in such a role, but more generally it draws attention to the importance of involving members of black minority ethnic (BME) communities in working alongside mainstream mental health services. We conclude that the involvement of BME community development workers inside, alongside and outside statutory services can potentially improve the quality of care for people from BME communities who use these services.

Judgement and the role of the metaphysics of values in medical ethics

Despite its authors' intentions, the four principles approach to medical ethics can become crudely algorithmic in practice. The first section sets out the bare bones of the four principles approach drawing out those aspects of Beauchamp and Childress's Principles of biomedical ethics that encourage this misreading. The second section argues that if the emphasis on the guidance of moral judgement is augmented by a particularist account of what disciplines it, then the danger can be reduced. In the third section, I consider how much the resultant picture diverges from Beauchamp and Childress's actual position.

Attentional limitations in the sensing of motion direction

Attentional constraints in the perceptual analysis of motion direction were examined using two independent paradigms: redundant target visual search and the analysis of fluctuations in discrimination accuracy at threshold. Results from both methods implied that directions of object motion are analyzed in parallel when those motions are translations, independent of the observer's line of sight. The registration of rotation direction appears to be subject to a qualitatively different protocol, one that is highly capacity limited and serial-like. These results suggest that scene-based descriptions, as opposed to image-based descriptions of motion, mediate the allocation of attention.

Can computer autoacquisition of medical information meet the needs of the future? A feasibility study in direct computation of the fine grained electronic medical record

The project describes feasibility testing of a two-year clinical deployment of an electronic record keeping system for primary care medicine that allowed financial medical management and clinical disease study without the encumbrance of human encoding. The software used an expert system for acquisition of historical information and automatic database encoding of each independent fact. The historical acquisition system was combined with a screen-based physician data entry system to create a fine-grained medical record. Fine-grained data allowed direct computer processing to mimic the ends that presently require human encoding--gatekeeping, disease characterization and remote disease surveillance. The project demonstrated the possibility of real time gatekeeping through direct analysis of data. Detection and characterization of disease states using statistical methods within the database was possible, however, limited in this study because of the large numbers of patient interviews required. The possibilities for remote disease monitoring and clinical studies are also discussed.

Attitudes towards the relevance of biological, behavioural and social sciences in nursing education

This paper explores the perceptions of staff and students regarding the supporting sciences within nursing education and how they feel such content relates to the 'real world' of nursing. A qualitative study examining the perceptions of students and teaching staff, particularly the concept of relevance, was conducted to explore factors which impact upon the integration of theory and practice. The teaching approaches used, assessment items selected, and the perceptions held about what nurses actually do all impinge upon what, and how, students learn in subjects which are essentially non-nursing in their orientation. Through an awareness of factors affecting how students and teaching staff actually approach supporting sciences content, better informed curriculum decisions can be made.

Prevention of youth violence: rationale and characteristics of 15 evaluation projects

Interpersonal violence is a major cause of injury, disability, and death, especially among youth. Evaluations of 15 youth violence-prevention projects are under way. Public health is concerned about health problems that need to be addressed via collective action. Public health involvement in addressing interpersonal violence among youths brings an emphasis on primary prevention, a systematic and scientific process, and integrative leadership. Few quantitative evaluations of violence-prevention projects have been done. The interventions are scientifically based and use a spectrum of strategies. Individually oriented strategies are more common than those directed toward peers, families, schools, or communities. Each project has a rigorous evaluation design. Twelve are randomized. Sample sizes range from 180 to 10,000. Participants range in age from 5 to 18 years, although most are in the middle-school years (11-14 years). At baseline, intervention and comparison groups are similar. Baseline data demonstrate high frequency of violent behavior, weapon carrying, and exposure to violence among the youthful participants. Field intervention and evaluation research is difficult and expensive. Difficulties encompass organizational programatic, and scientific issues; these difficulties reduce scientific interest and financial support for projects such as these. Public health has an important role to play in reducing violence. These projects will make important contributions to that task.

1/f noise in human cognition

When a person attempts to produce from memory a given spatial or temporal interval, there is inevitably some error associated with the estimate. The time course of this error was measured in a series of experiments where subjects repeatedly attempted to replicate given target intervals. Sequences of the errors in both spatial and temporal replications were found to fluctuate as 1/f noises. 1/f noise is encountered in a wide variety of physical systems and is theorized to be a characteristic signature of complexity.

A strategy for the design of membrane-permeable folypoly-gamma-glutamate synthetase inhibitors: "bay-region"-substituted 2-desamino-2-methyl-5,8-dideazafolate analogs

Previous attempts to design inhibitors of mammalian folylpolyglutamate synthetase (FPGS) have resulted in three classes of active compounds, all of which have charged moieties in the side chain, but structural alteration of the rest of the folate molecule has not seemed to be an avenue for drug discovery. However, groups in the side chain of folate analogs that bear charge distributions different from that of glutamic acid appear to prevent efficient transport into mammalian cells on the reduced folate carrier system. We now report that substituents at the 7-, 2'-, or 3'-position of 2-desamino-2-methyl-4-hydroxyquinazoline antifolates decrease or prevent the catalysis of diglutamate formation by FPGS but are compatible with efficient binding to the reduced folate carrier system. Thus, 5,8-dideazafolates with a 3'-alkyl group had a lower Vmax for FPGS than did the corresponding unsubstituted quinazolines, by a factor of 4-12, but these compounds inhibited the reaction of control FPGS substrates, indicating that the 3'-groups had much larger effects on catalytic activity than on binding to enzyme. A 7-methyl substituent affected the Vmax of a series of 5,8-dideazafolate compounds by a factor of 2-8, but this decrease in the catalytic rate was also accompanied by an increase in the Km of the substituted compounds by a factor of 10-100. The extent of the effect of a 7-methyl substituent on Vmax appeared to be dependent on the size of the substituent at N10. Different substituents at the 2'-position affected the kinetics of the FPGS reaction with one of three patterns, i.e., 1) a 2'-fluoro substituent both increased Vmax and decreased Km slightly, 2) either -OH or -NH2 decreased the Vmax without affecting the Km, and 3) 2'-Cl-, -CH3, -CF3, or -OCH3 substituents were found to both decrease Vmax and increase Km. Substitutions at the 7-, 2'-, or 3'-position had only minor effects on the ability of 2-desamino-2-methyl-4-oxoquinazolines to interfere with the transport of [3H]methotrexate into L1210 cells. Hence, these classes of compounds are likely to be efficiently transported by the reduced folate carrier system. We conclude that the region of the folate molecule bounded by the 7-, 6-, 9-, 10-, 3'-, and 2'-positions, the "bay region," is of major importance both for the binding of folates and folate analogs to FPGS and for the assumption of a conformation of the enzyme-substrate complex compatible with catalysis.(ABSTRACT TRUNCATED AT 400 WORDS)

Antagonism of androgen and estrogen effects in guinea pig seminal vesicle epithelium and fibromuscular stroma by keoxifene (LY156758)

Using separated epithelium (SVE) and fibromuscular stroma (SVM) of guinea pig seminal vesicle, the antihormonal effects of daily subcutaneous administration (14 and 28 days) of the benzothiophene keoxifene (LY156758; [6-hydroxy-2-(4-hydroxyphenyl)benzo(b) thien-3-yl] [4-(2-1-piperidinyl) ethoxyl] phenyl) methanone hydrochloride) in intact, castrate, and androgen/estrogen-maintained castrate animals was evaluated. The compound was devoid of agonist activity in castrated males, in that the compound had no stimulatory effect on SVM wet weight or DNA content. In vitro cytosolic binding of [3H]estradiol (E2) in the SVM was decreased in a concentration-dependent manner by keoxifene, but the compound did not perturb the binding of [3H]dihydrotestosterone (DHT) in the SVM or SVE. Likewise, keoxifene administration to castrated males treated with exogenous steroids antagonized the estrogen-induced hyperplastic response of the SVM, whereas no interference with androgen-induced growth of the SVM or SVE was observed. Keoxifene treatment of intact male guinea pigs produced regression of the androgen-sensitive SVE as well as the androgen/estrogen-sensitive SVM. Keoxifene-induced decreases in guinea pig serum testosterone levels were associated with this activity. Histological analysis of the seminal vesicle under these conditions suggests androgen deprivation. These findings indicate that keoxifene is a physiological antagonist of androgen action in the intact male guinea pig. The pure estrogen antagonist properties of keoxifene and its ability to decrease accessory sex organ epithelium and fibromuscular stroma in vivo suggest potential applications of the benzothiophenes in the medical management of prostatic neoplasia.