Comparison of procedural anxiety and pain associated with conventional transrectal ultrasound prostate biopsy to magnetic resonance imaging-ultrasound fusion-guided biopsy: a prospective cohort trial

BACKGROUND

Prostate cancer (PCa) diagnosis relies on biopsies, with transrectal ultrasound (TRUS) biopsies being common. Fusion biopsy (FB) offers improved diagnostic accuracy, but the pain and anxiety experienced by patients during biopsies is often overlooked. This study aims to compare pain and anxiety levels between standard TRUS-guided biopsy (STB) and systematic plus MRI/US fusion biopsy (STB + FB).

MATERIALS AND METHODS

The study involved adult men undergoing biopsies, receiving identical peri-procedural care, including 2% lidocaine jelly in the rectum and subsequent 1% lidocaine injections (10cc per side) into the prostate-seminal vesicle junction and prostatic apical areas bilaterally. The biopsy technique was chosen based on clinical and imaging findings. Pre- and post-biopsy anxiety levels were assessed using the State-Trait Anxiety Inventory (STAI) questionnaire, categorized as mild (20-37), moderate (38-44), or severe (45-80). Post-biopsy pain was evaluated on a numerical rating scale, ranging from 0 to 10.

RESULTS

Of the 165 patients, 99 underwent STB, and 66 underwent STB + FB. No significant differences were observed in age, race, prostate-specific antigen, prostate volume, or prior biopsies between the groups. The STB + FB group had more biopsy cores taken (16.2 vs. 12, p = 0.001) and a longer procedure time (23 vs. 10 min, p = 0.001). STB biopsy patients experienced lower post-procedural anxiety compared to STB + FB, with a mean difference of -7 (p = 0.001, d = 0.92). In the STB + FB group, 89% experienced severe post-procedural anxiety compared to 59% in STB (p = 0.002). There was no significant difference in post-procedural pain (p = 0.7). Patients with prior biopsies had significantly higher STAI(S) anxiety scores (p = 0.005), and the number of prior biopsies correlated with anxiety severity (p = 0.04) in STB + FB group.

CONCLUSION

In summary, STB + FB group demonstrated higher post-procedural anxiety levels than the STB group, with no difference in pain levels. Additionally, patients with a history of repeat biopsies were more likely to exhibit higher STAI(S) anxiety scores.

Addressing racial disparities in prostate cancer pathology prediction models: external validation and comparison of four models of pathological outcome prediction before radical prostatectomy in the multiethnic SEARCH cohort

BACKGROUND

Certain widely used pathological outcome prediction models that were developed in tertiary centers tend to overpredict outcomes in the community setting; thus, the Michigan Urological-Surgery Improvement Collaborative (MUSIC) model was developed in general urology practice to address this issue. Additionally, the development of these models involved a relatively small proportion of Black men, potentially compromising the accuracy of predictions in this patient group. We tested the validity of the MUSIC and three widely used nomograms to compare their overall and race-stratified predictive performance.

METHODS

We extracted data from 4139 (1138 Black) men from the Shared Equal Access Regional Cancer Hospital (SEARCH) database of the Veterans Affairs health system. The predictive performance of the MUSIC model was compared to the Memorial-Sloan Kettering (MSK), Briganti-2012, and Partin-2017 models for predicting lymph-node invasion (LNI), extra-prostatic extension (EPE), and seminal vesicle invasion (SVI).

RESULTS

The median PSA of Black men was higher than White men (7.8 vs. 6.8 ng/ml), although they were younger by a median of three years and presented at a lower-stage disease. MUSIC model showed comparable discriminatory capacity (AUC:77.0%) compared to MSK (79.2%), Partin-2017 (74.6%), and Briganti-2012 (76.3%), with better calibration for LNI. AUCs for EPE and SVI were 72.7% and 76.9%, respectively, all comparable to the MSK and Partin models. LNI AUCs for Black and White men were 69.6% and 79.6%, respectively, while EPE and SVI AUCs were comparable between races. EPE and LNI had worse calibration in Black men. Decision curve analysis showed MUSIC superiority over the MSK model in predicting LNI, especially among Black men.

CONCLUSION

Although the discriminatory performance of all models was comparable for each outcome, the MUSIC model exhibited superior net benefit to the MSK model in predicting LNI outcomes among Black men in the SEARCH population.

Urinary fatty acid biomarkers for prostate cancer detection

The lack of accuracy in the current prostate specific antigen (PSA) test for prostate cancer (PCa) screening causes around 60-75% of unnecessary prostate biopsies. Therefore, alternative diagnostic methods that have better accuracy and can prevent over-diagnosis of PCa are needed. Researchers have examined various potential biomarkers for PCa, and of those fatty acids (FAs) markers have received special attention due to their role in cancer metabolomics. It has been noted that PCa metabolism prefers FAs over glucose substrates for continued rapid proliferation. Hence, we proposed using a urinary FAs based model as a non-invasive alternative for PCa detection. Urine samples collected from 334 biopsy-designated PCa positive and 232 biopsy-designated PCa negative subjects were analyzed for FAs and lipid related compounds by stir bar sorptive extraction coupled with gas chromatography/mass spectrometry (SBSE-GC/MS). The dataset was split into the training (70%) and testing (30%) sets to develop and validate logit models and repeated for 100 runs of random data partitioning. Over the 100 runs, we confirmed the stability of the models and obtained optimal tuning parameters for developing the final FA based model. A PSA model using the values of the patients' PSA test results was constructed with the same cohort for the purpose of comparing the performances of the FA model against PSA test. The FA final model selected 20 FAs and rendered an AUC of 0.71 (95% CI = 0.67-0.75, sensitivity = 0.48, and specificity = 0.83). In comparison, the PSA model performed with an AUC of 0.51 (95% CI = 0.46-0.66, sensitivity = 0.44, and specificity = 0.71). The study supports the potential use of urinary FAs as a stable and non-invasive alternative test for PCa diagnosis.

Intratumoural immunotherapy plus focal thermal ablation for localized prostate cancer

Major advances have been made in the use of immunotherapy for the treatment of solid tumours, including the use of intratumourally injected immunotherapy instead of systemically delivered immunotherapy. The success of immunotherapy in prostate cancer treatment has been limited to specific populations with advanced disease, which is thought to be a result of prostate cancer being an immunologically 'cold' cancer. Accordingly, combining intratumoural immunotherapy with other treatments that would increase the immunological heat of prostate cancer is of interest. Thermal ablation therapy is currently one of the main strategies used for the treatment of localized prostate cancer and it causes immunological activation against prostate tissue. The use of intratumoural immunotherapy as an adjunct to thermal ablation offers the potential to elicit a systemic and lasting adaptive immune response to cancer-specific antigens, leading to a synergistic effect of combination therapy. The combination of thermal ablation and immunotherapy is currently in the early stages of investigation for the treatment of multiple solid tumour types, and the potential for this combination therapy to also offer benefit to prostate cancer patients is exciting.

Evaluation of Recurrent Disease after Radiation Therapy for Patients Considering Local Salvage Therapy: Past vs. Contemporary Management

Recurrent prostate cancer after primary treatment with radiation therapy is a common problem. Patients with localized recurrence may benefit from salvage therapy, but careful patient selection is crucial because not all patients will benefit from local salvage therapy, and salvage therapy has increased morbidity compared to primary treatments for prostate cancer. This review aims to provide an overview of the evaluation of patients with recurrent disease after radiation therapy and how it is continuing to evolve with increasing data on outcomes, as well as improving technologies and techniques. Our enhanced understanding of treatment outcomes and risk stratification has influenced the identification of patients who may benefit from local salvage treatment. Advances in imaging and biopsy techniques have enhanced the accuracy of locating the recurrence, which affects treatment decisions. Additionally, the growing interest in image-targeted ablative therapies that have less morbidity and complications than whole-gland therapies for suitable patients influences the evaluation process for those considering focal salvage therapy. Although significant changes have been made in the diagnostic evaluation of patients with recurrent disease after radiation therapy, it remains unclear whether these changes will ultimately improve patient outcomes.

Primary Whole-gland Ablation for the Treatment of Clinically Localized Prostate Cancer: A Focal Therapy Society Best Practice Statement

CONTEXT

Whole-gland ablation is a feasible and effective minimally invasive treatment for localized prostate cancer (PCa). Previous systematic reviews supported evidence for favorable functional outcomes, but oncological outcomes were inconclusive owing to limited follow-up.

OBJECTIVE

To evaluate the real-world data on the mid- to long-term oncological and functional outcomes of whole-gland cryoablation and high-intensity focused ultrasound (HIFU) in patients with clinically localized PCa, and to provide expert recommendations and commentary on these findings.

EVIDENCE ACQUISITION

We performed a systematic review of PubMed, Embase, and Cochrane Library publications through February 2022 according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. As endpoints, baseline clinical characteristics, and oncological and functional outcomes were assessed. To estimate the pooled prevalence of oncological, functional, and toxicity outcomes, and to quantify and explain the heterogeneity, random-effect meta-analyses and meta-regression analyses were performed.

EVIDENCE SYNTHESIS

Twenty-nine studies were identified, including 14 on cryoablation and 15 on HIFU with a median follow-up of 72 mo. Most of the studies were retrospective (n = 23), with IDEAL (idea, development, exploration, assessment, and long-term study) stage 2b (n = 20) being most common. Biochemical recurrence-free survival, cancer-specific survival, overall survival, recurrence-free survival, and metastasis-free survival rates at 10 yr were 58%, 96%, 63%, 71-79%, and 84%, respectively. Erectile function was preserved in 37% of cases, and overall pad-free continence was achieved in 96% of cases, with a 1-yr rate of 97.4-98.8%. The rates of stricture, urinary retention, urinary tract infection, rectourethral fistula, and sepsis were observed to be 11%, 9.5%, 8%, 0.7%, and 0.8%, respectively.

CONCLUSIONS

The mid- to long-term real-world data, and the safety profiles of cryoablation and HIFU are sound to support and be offered as primary treatment for appropriate patients with localized PCa. When compared with other existing treatment modalities for PCa, these ablative therapies provide nearly equivalent intermediate- to long-term oncological and toxicity outcomes, as well as excellent pad-free continence rates in the primary setting. This real-world clinical evidence provides long-term oncological and functional outcomes that enhance shared decision-making when balancing risks and expected outcomes that reflect patient preferences and values.

PATIENT SUMMARY

Cryoablation and high-intensity focused ultrasound are minimally invasive treatments available to selectively treat localized prostate cancer, considering their nearly comparable intermediate- to long term cancer control and preservation of urinary continence to other radical treatments in the primary setting. However, a well-informed decision should be made based on one's values and preferences.

Salvage Cryoablation for Recurrent Prostate Cancer Following Primary External Beam Radiotherapy or Primary Cryotherapy: A Propensity Score Matched Analysis of Mid-term Oncologic and Functional Outcomes

INTRODUCTION

Local prostate cancer recurrence following radiotherapy (XRT) or cryoablation (CRYO) may be addressed with salvage cryotherapy (SCT), although little is known about how the primary treatment modality affects SCT results. Oncologic and functional outcomes of patients who underwent SCT after primary XRT (XRT-SCT) or cryoablation (CRYO-SCT) were studied.

METHODS

Data was collected using the Duke Prostate Cancer database and the Cryo On-Line Data (COLD) registry. The primary outcome was biochemical progression-free survival (BPFS).  Urinary incontinence, rectourethral fistula, and erectile dysfunction were secondary outcomes. The Kaplan-Meier log-rank test and univariable/multivariable Cox proportional hazards (CPH) models were utilized to evaluate BPFS between groups.

RESULTS

419 XRT-SCT and 63 CRYO-SCT patients met inclusion criteria, that was reduced to 63 patients in each cohort after propensity matching. There was no difference in BPFS at 2 and 5 years both before (P = .5 and P = .7) and after matching (P = .6 and P = .3). On multivariable CPH, BPFS was comparable between treatment groups (CRYO-SCT, HR=1.1, [0.2-2.2]).  On the same analysis, BPFS was lower in D'Amico high-risk (HR 3.2, P < .01) and intermediate-risk (HR 1.95, P < .05) categories compared to low-risk. There was no significant difference in functional outcomes between cohorts.

CONCLUSION

Following primary cryotherapy, salvage cryoablation provides comparable intermediate oncological outcomes and functional outcomes compared to primary radiotherapy.

Intermediate-term oncological and functional outcomes of salvage cryotherapy for the management of prostate cancer recurrence after primary brachytherapy versus primary cryotherapy: A propensity score-matched analysis

BACKGROUND

Salvage cryotherapy (SCT) is widely used to treat prostate cancer (PCa) recurrence after radiotherapy (RT). We studied the intermediate oncological and functional outcomes of patients who underwent SCT following cryotherapy (CRYO-SCT) recurrence and compare it to recurrence after brachytherapy (BT-SCT).

METHODS

An IRB-approved retrospective cohort study utilizing patient data from the Cryo On-Line Data Registry and the Duke PCa database between 1992 and 2016. Biochemical recurrence (BCR) using Phoenix criteria was the primary endpoint assessed at 2- and 5-years post-SCT. Secondary endpoints assessed functional outcomes including urinary continence, erectile function, and recto-urethral fistula. Association between treatment and biochemical progression-free survival was assessed using inverse probability weighted (IPTW) Cox proportional hazards regression. The differences in the secondary functional outcomes were assessed by Pearson's χ2 test or Fisher's exact test, corrected for IPTW.

RESULTS

A total of 194 patients met inclusion criteria. The BCR rate for BT-SCT and CRYO-SCT was 23 (20.4%) and 17 (21%) at 2 years and 30 (26.5%) and 22 (27.2%) at 5 years according to Phoenix criteria. There was no statistical difference in 2 years (hazard ratio [HR] 0.9; 95% confidence interval [CI], 0.5-1.7, p = 0.7) or 5-year BCR (HR: 0.86; 95% CI, 0.5-1.5, p = 0.6) between the groups. The functional outcomes like urinary continence (p = 0.4), erectile function (p = 0.1), and recto-urethral fistula (p = 0.3) were not statistically different.

CONCLUSION

CRYO-SCT appears to be well tolerated, with comparable oncological and functional outcomes to patients failing primary BT. The findings also demonstrated that SCT can render a significant number of patients biochemically free of disease after initial CRYO with minimal morbidity. SCT is a viable treatment option to salvage local PCa recurrence following either BT or cryoablation failure.

Management of urologic prosthetic reservoirs at the time of inguinal or pelvic surgery

INTRODUCTION

The artificial urinary sphincter and 3-piece inflatable penile prosthesis each require a fluid storage component and thus have components in the inguinal and pelvic regions. Because of this, patients with urologic prosthetics sometimes present challenges during future nonprosthetic operations. Presently, there is no established guideline for device management with ensuing inguinal or pelvic surgery.

AIMS

This article outlines concerns during pelvic and inguinal surgery for patients with an artificial urinary sphincter and/or inflatable penile prosthesis and proposes an algorithm for preoperative surgical planning and decision making.

METHODS

We conducted a narrative review of the literature on operative management of these prosthetic devices. Publications were identified by searching electronic databases. Only peer-reviewed publications available in English were considered for this review.

RESULTS

We review the important considerations as well as available options for operative management of these prosthetic devices during subsequent nonprosthetic surgery and highlight the advantages and disadvantages of each. Finally, we suggest a framework for helping surgeons determine which management strategy is most appropriate for their individual patients.

CONCLUSION

The best management strategy will differ depending on patient values, the planned surgery, and patient-specific factors. Surgeons should understand and counsel patients on all available options and encourage informed, shared decision making to determine the best individualized approach.

Reconciling discordance between PI-RADS 4 lesions and targeted biopsy: Early experience of a multidisciplinary quality improvement protocol with PI-RADS 4 subcategorization

PURPOSE

PI-RADS 4 lesions are considered to have a "high" likelihood of clinically-significant prostate cancer (csPCa). However, patients undergoing targeted biopsy have a range of histologic findings. Understanding discordant cases is critical to improve diagnostic accuracy and inform subsequent management. We studied early findings from implementation of a multidisciplinary Quality Improvement (QI) protocol for reconciling discordance and evaluate the potential heterogeneity of PI-RADS 4.

METHODS

Patients with mpMRI PI-RADS 4 lesions undergoing fusion-targeted biopsy from January 2017 to May 2021 were retrospectively reviewed. The discordant targeted biopsy pathology (benign/GG1) was evaluated utilizing a QI protocol and all lesions were subcategorized based on ADC values. Positive Predictive Value (PPV) for PI-RADS 4 lesions overall and the Cancer Detection Rate (CDR) for subcategorized lesions were calculated.

RESULTS

248 patients with 286 lesions were reviewed. Prior to re-review, PI-RADS 4 PPV for ≥ GG1 and ≥ GG2 lesions were 0.55 and 0.34, increasing to 0.67 and 0.43 following reconciliation. Lesion subcategorization based on ADC value as higher suspicion (4+) and lower suspicion (4-) resulted in 158 and 117 lesions, with reverse-fusion analysis revealing that 61% and 17% of lesions contained csPCa, respectively. Subgroup analysis among PI-RADS 4+ lesions led to an increase in the CDR to 75% and 61% for ≥ GG1 and ≥ GG2.

CONCLUSION

Use of multidisciplinary QI protocol to review discordance cases of PI-RADS 4 improves diagnostic accuracy and guides subsequent management. Our findings highlight the known heterogeneity of this category with reference to csPCa CDR, suggesting the potential value of PI-RADS 4 subcategorization.

Exudate From Retail Chicken Liver Packaging Allows for Survival of Naturally Occurring Campylobacter, Coliforms, and Aerobic Microorganisms Under Drying Conditions

Campylobacter spp. are a leading cause of human foodborne illness associated with chicken meat products in the United States. Chicken livers, including exudate from packaging, commonly carry Campylobacter and could be a source of illness if mishandled. Survivability of naturally occurring Campylobacter, total aerobic bacteria, and coliforms was determined under drying conditions in two consumer simulated environments: moist sponge and solid surface. Fresh chicken liver exudate was dispensed onto sponges and glass slides and allowed to dry under ambient conditions for 7 days. Bacterial concentration was measured at 0, 6, 24, 48, 72, and 168 h. Total aerobic population did not decrease by more than one log over 7 days and did not correlate to water activity or time in either simulation. Coliform concentrations increased in sponge simulations but decreased in solid surface simulations. Further, coliform concentrations were significantly higher in sponge simulations than in solid surface. Campylobacter was naturally present in exudate and survived at least to 6 h in every trial. Campylobacter was recoverable at 24 h in some sponge trials. However, Campylobacter concentration was strongly correlated to water activity. Fresh chicken liver exudate could present a risk of campylobacteriosis to consumers if mishandled even after drying.

Diversity and antimicrobial resistance of Enterococcus from the Upper Oconee Watershed, Georgia

AIM

It is well-known that enterococci are abundant in the environment; however, the role of surface water as a reservoir of antimicrobial-resistant enterococci remains largely undefined. In this study, surface water samples were collected over a 2-year period from the Upper Oconee watershed, Athens, GA to examine enterococci and their antimicrobial resistance.

METHODS AND RESULTS

Approximately 97% (445/458) of the samples were positive for enterococci and a total of 637 enterococci were isolated. The predominant species were Enterococcus casseliflavus (33·6%) followed by Enterococcus faecalis (26·5%) and Enterococcus hirae (13·2%). Regardless of species, the highest levels of resistance were to lincomycin (88·5%) and tetracycline (13%); isolates also exhibited resistance to newer antimicrobials, daptomycin (8·9%) and tigecycline (6·4%). Multidrug resistance (resistance ≥3 antimicrobial classes) was observed to as many as five classes of antimicrobials. Resistant enterococci appeared to be randomly dispersed over the seasons rather than clustered by species or antimicrobial resistance.

CONCLUSIONS

This study demonstrated that surface waters contain a large population of diverse species of antimicrobial-resistant enterococci, including resistance to new antimicrobials.

SIGNIFICANCE AND IMPACT OF THE STUDY

These results may indicate the potential of human intestinal illness and/or colonization of the human gut with resistant enterococci as enterococci correlate with increased disease risk to humans during recreational exposure to water.

Prevalence and characterization of Escherichia coli isolated from the Upper Oconee Watershed in Northeast Georgia

Surface waters are important sources of water for drinking, industrial, agricultural, and recreational uses; hence, contamination of water by fecal, pathogenic, or antimicrobial resistant (AR) bacteria is a major environmental and public health concern. However, very little data is available on prevalence of these bacteria in surface water throughout a watershed. This study aimed to characterize Escherichia coli present in the Upper Oconee Watershed, a mixed-use watershed in Athens, GA, USA for potential pathogenicity and AR. E. coli were enumerated by colony counts, cultured by enrichment and direct plating, and characterized by phylo-groups, diarrheagenic pathotypes, and antimicrobial susceptibility. From the analysis, 99.3% (455/458) of the total samples were positive for E. coli resulting in 496 isolates. E. coli counts were as high as 1.2×10⁴ CFU/100 ml, which is above the United States Environmental Protection Agency (U.S. EPA) threshold for recreational water (235 CFU/100 ml based on a one-time measurement). Phylo-groups B2 (31.7%; 157/496) and B1 (30.8%; 153/496) were the most prevalent among the isolates. Enteropathogenic E. coli (EPEC) (19/496) and Shiga toxin-producing E. coli (STEC) (1/496) were the only diarrheagenic pathotypes detected. AR was observed in 6.9% (34/496) of the isolates, 15 of which were multidrug resistant (MDR; resistance to two or more classes of antimicrobials). Tetracycline resistance was most often detected (76.5%; 26/34), followed by ampicillin (32.4%; 11/34), streptomycin (23.5%; 8/34), sulfisoxazole (23.5%; 8/34), and nalidixic acid (14.7%; 5/34). Results from this study showed that E. coli is prevalent in high levels in the Upper Oconee Watershed, suggesting possible widespread fecal contamination. The presence of pathogenic, AR E. coli in the watershed indicates that environmental water can serve as a reservoir of resistant bacteria that may be transferred to humans through drinking and recreational activities.

Neutralization of Bactericidal Activity Related to Antimicrobial Carryover in Broiler Carcass Rinse Samples

Studies were conducted to examine the ability of three chemicals to neutralize residual antibacterial activity of commercial antimicrobial chemicals used in poultry processing. Chemical antimicrobial interventions used in poultry processing may have potential for carryover into whole poultry carcass buffered peptone water (BPW) rinses collected for monitoring Salmonella contamination. Such carryover may lead to false-negative results due to continuing bactericidal action of the antimicrobial chemicals in the rinse. To simulate testing procedures used to detect Salmonella contamination, studies were conducted by separately adding test neutralizers (highly refined soy lecithin, sodium thiosulfate, or sodium bicarbonate) to BPW and using these solutions as carcass rinses. Control samples consisted of BPW containing no additional neutralizing agents. One of four antimicrobial solutions (cetylpyridinium chloride, peroxyacetic acid, acidified sodium chlorite, and a pH 1 hydrochloric:citric acid mix) was then added to the rinses. The four antimicrobial solutions were prepared at maximum allowable concentrations and diluted with modified BPW rinses to volumes simulating maximum carryover. These solutions were then inoculated with a mixed culture of five nalidixic acid-resistant Salmonella serovars at 10⁶ CFU/mL. The inoculated rinse was stored at 4°C for 24 h, and Salmonella was enumerated by direct plating on brilliant green sulfa agar supplemented with nalidixic acid. Results indicate that incorporation of optimal concentrations of three neutralizing agents into BPW neutralized the demonstrated carryover effects of each of the four antimicrobial solutions tested, allowing recovery of viable Salmonella at 10⁶ CFU/mL (P > 0.05), equivalent to recovery from carcass rinses with no antimicrobial carryover. Incorporation of these neutralizers in BPW for Salmonella monitoring may reduce false-negative results and aid regulatory agencies in accurate reporting of Salmonella contamination of poultry.

Carcass orientation and drip time affect potential surface water carryover for broiler carcasses subjected to a post-chill water dip or spray1

To estimate the potential for residual antimicrobial solution carryover, surface water accumulation and loss was measured on post-chill carcasses that were either dipped or sprayed with water. For all experiments, broilers were slaughtered, soft or hard scalded, defeathered, and eviscerated. Carcasses were immersion chilled, allowed to drip, and post-chill carcass weight (CW) recorded. For water dip treatment, carcasses were dipped for 0.5 min in water and hung by a wing (n = 33) or a leg (n = 30) and CW recorded at 0, 0.5, 1, 2, and 5 min post-dip. For water spray treatment, individual carcasses were hung by either the wings (n = 35) or legs (n = 34) from a shackle suspended from a scale. Water was sprayed at 80 psi and post-spray CW recorded. Initial water accumulation (0 min) for dipped carcasses was not significantly different (P > 0.05) for carcasses hung by the leg (101.0 g) or wing (108.8 g). Following the 5 min drip time, 31 g of water remained on the carcasses hung by the leg and only 10 g on carcasses hung by the wing (P < 0.05). When carcasses were sprayed with water, initial water accumulation (0 min) was 62 g for carcasses hung by the legs and 60 g for carcasses hung by the wings (P > 0.05). Following the 5 min drip time, 1 g or no water remained on the sprayed carcasses (P > 0.05). Carcasses that were dipped and hung by a leg for 5 min retained significantly more water (31 g) than carcasses that were dipped and hung by a wing (10 g) or sprayed carcasses hung either way (0.3 g) (P < 0.05). Post-chill water dip resulted in significantly higher initial carcass water accumulation than spraying (105 g vs. 61 g, P < 0.05). Carcass orientation during dripping only affected the amount of retained water for dipped carcasses. Dipped carcasses hung by a leg have the highest potential for residual carcass antimicrobial solution carryover and sprayed carcasses hung by either orientation have the lowest potential for residual antimicrobial solution carryover.

Effect of Simulated Sanitizer Carryover on Recovery of Salmonella from Broiler Carcass Rinsates

Numerous antimicrobial chemicals are currently utilized as processing aids with the aim of reducing pathogenic bacteria on processed poultry carcasses. Carryover of active sanitizer to a carcass rinse solution intended for recovery of viable pathogenic bacteria by regulatory agencies may cause false-negative results. This study was conducted to document the potential carryover effect of five sanitizing chemicals commonly used as poultry processing aids for broilers in a postchill dip. The effect of postdip drip time on the volume of sanitizer solution carryover was first determined by regression of data obtained from 10 carcasses. The five sanitizer solutions were diluted with buffered peptone water at 0-, 1-, and 5-min drip time equivalent volumes as determined by the regression analysis. These solutions were then spiked to 10(5) CFU/ml with a mixture of five nalidixic acid-resistant Salmonella enterica serovars, stored at 4°C for 24 h, and finally enumerated by plate count on brilliant green sulfa agar containing nalidixic acid. At the 0- and 1-min drip time equivalents, no Salmonella recovery was observed in three of the five sanitizers studied. At the 5-min drip time equivalent, one of these sanitizers still exhibited significant (P ≤ 0.05) bactericidal activity. These findings potentially indicate that the currently utilized protocol for the recovery of Salmonella bacteria from postchill sanitizer interventions may lead to false-negative results due to sanitizer carryover into the carcass rinsate.

Genetic architecture of adiposity in the cross of LG/J and SM/J inbred mice

The genetic basis of variation in obesity in human populations is thought to be owing to many genes of relatively small effect and their interactions. The LG/J by SM/J intercross of mouse inbred strains provides an excellent model system in which to investigate multigenic obesity. We previously mapped a large number of quantitative trait loci (QTLs) affecting adult body weight in this cross. We map body composition traits, adiposity, and skeletal size, in a replicate F2 intercross of the same two strains containing 510 individuals. Using interval-mapping methods, we located eight QTLs affecting adiposity (Adip1-8). Two of these adiposity loci also affected tail length (Adip4 and Adip6) along with seven additional tail length QTLs (Skl1-7). A further four QTLs (Wt1-4) affect adult weight but not body composition. These QTLs have relatively small effects, typically about 0.2-0.4 standard deviation units, and account for between 3% and 10% of the variance in individual characters. All QTLs participated in epistatic interactions with other QTLs. Most of these interactions were due to additive-by-additive epistasis, which can nullify the apparent effects of single loci in our population. Adip8 interacts with all the other adiposity QTLs and seems to play a central role in the genetic system affecting obesity in this cross. Only two adiposity QTLs, Adip4 and Adip6, also affect tail length, indicating largely separate genetic control of variation in adiposity and skeletal size. Body size and obesity QTLs in the same locations as those discovered here are commonly found in mapping experiments with other mouse strains.

Double-strand conformation polymorphism (DSCP) analysis of the mitochondrial control region generates highly variable markers for population studies in a social insect

Genetic markers were obtained for the termite Nasutitermes corniger by DSCP (double-strand conformation polymorphism) analysis of PCR-amplified mitochondrial control region DNA. This procedure revealed twenty-one haplotypes in forty-four colonies, whereas a restriction fragment length polymorphism analysis detected only nine haplotypes. Sequence analysis of DSCP fragments of contrasting mobilities suggests that the electrophoretic haplotypes are caused by DNA curvature in this highly AT-rich region. DSCP markers showed that some termite colonies contained maternally unrelated queens, each of which produced worker offspring. This pattern is consistent with nest founding by unrelated queens. Due to the availability of conserved primers for the mtDNA control region, DSCP analysis may readily reveal comparatively high levels of variation in a wide variety of organisms.

Spatial dynamics of colony interactions in young populations of the fire ant Solenopsis invicta

Newly founded colonies of the fire ant Solenopsis invicta compete intensely by brood raids, which result in a rapid reduction of colony density. Experimental plantings of colonies and analyses of sequential maps were used to examine the importance of spatial pattern in the dynamics of young populations. Colony positions were initially clumped in naturally founded cohorts, but were regular in most mature populations. Incipient colonies planted in clumped patterns were more likely to engage in brood raids than colonies planted in regular hexagonal patterns at the same average density. However, contrary to what would be expected if local crowding increased mortality, no significant increases in spatial regularity were observed during brood raiding either in the experimentally planted populations or in a natural population of more than 1200 incipient colonies. These results show that it may be difficult to infer the degree of past or current competition by passive analysis of spatial data even when field experiments show that the probability of mortality depends on local spacing.

Directed biosynthesis of 5"-fluoropactamycin in Streptomyces pactum

A new pactamycin analogue, 5"-fluoropactamycin, was prepared by directed biosynthesis. Supplementation of the fermentation medium of Streptomyces pactum, var. pactum with 3-amino-5-fluorobenzoic acid, an analogue of 3-aminobenzoic acid, an advanced precursor in pactamycin biosynthesis, resulted in co-production of pactamycin and the new pactamycin analogue. A similar feeding experiment with 3-amino-5-methylbenzoic acid did not result in formation of the corresponding methylated pactamycin analogue, but only in inhibition of pactamycin production. Comparison of antimicrobial and cytotoxic activities of pactamycin and 5"-fluoropactamycin showed no significant differences.

Nest-mate recognition based on heritable odors in the termite Microcerotermes arboreus

Workers of the Neotropical termite Microcerotermes arboreus distinguish nest mates from other conspecifics by odor. A controlled breeding experiment demonstrated a genetic component to variation in colony odors. Workers were less aggressive toward unfamiliar relatives than toward nonrelatives and distinguished degree of relatedness among unfamiliar workers. Unfamiliar relatives were attacked more often than nest mates, despite similar levels of genetic relatedness; thus, nest-mate recognition is not based solely upon heritable characteristics of individual workers. No difference was detected between the effects of cues inherited through the mother and cues inherited through the father.