Genomics and Artificial Intelligence: Prostate Cancer

Artificial intelligence (AI) is revolutionizing prostate cancer genomics research. By leveraging machine learning and deep learning algorithms, researchers can rapidly analyze vast genomic datasets to identify patterns and correlations that may be missed by traditional methods. These AI-driven insights can lead to the discovery of novel biomarkers, enhance the accuracy of diagnosis, and predict disease progression and treatment response. As such, AI is becoming an indispensable tool in the pursuit of personalized medicine for prostate cancer.

Artificial Intelligence-Based Video Feedback to Improve Novice Performance on Robotic Suturing Skills: A Pilot Study

Introduction: Automated skills assessment can provide surgical trainees with objective, personalized feedback during training. Here, we measure the efficacy of artificial intelligence (AI)-based feedback on a robotic suturing task. Materials and Methods: Forty-two participants with no robotic surgical experience were randomized to a control or feedback group and video-recorded while completing two rounds (R1 and R2) of suturing tasks on a da Vinci surgical robot. Participants were assessed on needle handling and needle driving, and feedback was provided via a visual interface after R1. For feedback group, participants were informed of their AI-based skill assessment and presented with specific video clips from R1. For control group, participants were presented with randomly selected video clips from R1 as a placebo. Participants from each group were further labeled as underperformers or innate-performers based on a median split of their technical skill scores from R1. Results: Demographic features were similar between the control (n = 20) and feedback group (n = 22) (p > 0.05). Observing the improvement from R1 to R2, the feedback group had a significantly larger improvement in needle handling score (0.30 vs -0.02, p = 0.018) when compared with the control group, although the improvement of needle driving score was not significant when compared with the control group (0.17 vs -0.40, p = 0.074). All innate-performers exhibited similar improvements across rounds, regardless of feedback (p > 0.05). In contrast, underperformers in the feedback group improved more than the control group in needle handling (p = 0.02). Conclusion: AI-based feedback facilitates surgical trainees' acquisition of robotic technical skills, especially underperformers. Future research will extend AI-based feedback to additional suturing skills, surgical tasks, and experience groups.

A Multi-institution Study on the Association of Virtual Reality Skills with Continence Recovery after Robot-assisted Radical Prostatectomy

BACKGROUND

Virtual reality (VR) simulators are increasingly being used for surgical skills training. It is unclear what skills are best improved via VR, translate to live surgical skills, and influence patient outcomes.

OBJECTIVE

To assess surgeons in VR and live surgery using a suturing assessment tool and evaluate the association between technical skills and a clinical outcome.

DESIGN, SETTING, AND PARTICIPANTS

This prospective five-center study enrolled participants who completed VR suturing exercises and provided live surgical video. Graders provided skill assessments using the validated End-To-End Assessment of Suturing Expertise (EASE) suturing evaluation tool.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

A hierarchical Poisson model was used to compare skill scores among cohorts and evaluate the association of scores with clinical outcomes. Spearman's method was used to assess correlation between VR and live skills.

RESULTS AND LIMITATIONS

Ten novices, ten surgeons with intermediate expertise (median 64 cases, interquartile range [IQR] 6-80), and 26 expert surgeons (median 850 cases, IQR 375-3000) participated in this study. Intermediate and expert surgeons were significantly more likely to have ideal scores in comparison to novices for the subskills needle hold angle, wrist rotation, and wrist rotation needle withdrawal (p < 0.01). For both intermediate and expert surgeons, there was positive correlation between VR and live skills for needle hold angle (p < 0.05). For expert surgeons, there was a positive association between ideal scores for VR needle hold angle and driving smoothness subskills and 3-mo continence recovery (p < 0.05). Limitations include the size of the intermediate surgeon sample and clinical data limited to expert surgeons.

CONCLUSIONS

EASE can be used in VR to identify skills to improve for trainee surgeons. Technical skills that influence postoperative outcomes may be assessable in VR.

PATIENT SUMMARY

This study provides insights into surgical skills that translate from virtual simulation to live surgery and that have an impact on urinary continence after robot-assisted removal of the prostate. We also highlight the usefulness of virtual reality in surgical education.

Development of a Classification System for Live Surgical Feedback

Importance

Live feedback in the operating room is essential in surgical training. Despite the role this feedback plays in developing surgical skills, an accepted methodology to characterize the salient features of feedback has not been defined.

Objective

To quantify the intraoperative feedback provided to trainees during live surgical cases and propose a standardized deconstruction for feedback.

Design, Setting, and Participants

In this qualitative study using a mixed methods analysis, surgeons at a single academic tertiary care hospital were audio and video recorded in the operating room from April to October 2022. Urological residents, fellows, and faculty attending surgeons involved in robotic teaching cases during which trainees had active control of the robotic console for at least some portion of a surgery were eligible to voluntarily participate. Feedback was time stamped and transcribed verbatim. An iterative coding process was performed using recordings and transcript data until recurring themes emerged.

Exposure

Feedback in audiovisual recorded surgery.

Main Outcomes and Measures

The primary outcomes were the reliability and generalizability of a feedback classification system in characterizing surgical feedback. Secondary outcomes included assessing the utility of our system.

Results

In 29 surgical procedures that were recorded and analyzed, 4 attending surgeons, 6 minimally invasive surgery fellows, and 5 residents (postgraduate years, 3-5) were involved. For the reliability of the system, 3 trained raters achieved moderate to substantial interrater reliability in coding cases using 5 types of triggers, 6 types of feedback, and 9 types of responses (prevalence-adjusted and bias-adjusted κ range: a 0.56 [95% CI, 0.45-0.68] minimum for triggers to a 0.99 [95% CI, 0.97-1.00] maximum for feedback and responses). For the generalizability of the system, 6 types of surgical procedures and 3711 instances of feedback were analyzed and coded with types of triggers, feedback, and responses. Significant differences in triggers, feedback, and responses reflected surgeon experience level and surgical task being performed. For example, as a response, attending surgeons took over for safety concerns more often for fellows than residents (prevalence rate ratio [RR], 3.97 [95% CI, 3.12-4.82]; P = .002), and suturing involved more errors that triggered feedback than dissection (RR, 1.65 [95% CI, 1.03-3.33]; P = .007). For the utility of the system, different combinations of trainer feedback had associations with rates of different trainee responses. For example, technical feedback with a visual component was associated with an increased rate of trainee behavioral change or verbal acknowledgment responses (RR, 1.11 [95% CI, 1.03-1.20]; P = .02).

Conclusions and Relevance

These findings suggest that identifying different types of triggers, feedback, and responses may be a feasible and reliable method for classifying surgical feedback across several robotic procedures. Outcomes suggest that a system that can be generalized across surgical specialties and for trainees of different experience levels may help galvanize novel surgical education strategies.

Exploring the Use of Artificial Intelligence in the Management of Prostate Cancer

PURPOSE OF REVIEW

This review aims to explore the current state of research on the use of artificial intelligence (AI) in the management of prostate cancer. We examine the various applications of AI in prostate cancer, including image analysis, prediction of treatment outcomes, and patient stratification. Additionally, the review will evaluate the current limitations and challenges faced in the implementation of AI in prostate cancer management.

RECENT FINDINGS

Recent literature has focused particularly on the use of AI in radiomics, pathomics, the evaluation of surgical skills, and patient outcomes. AI has the potential to revolutionize the future of prostate cancer management by improving diagnostic accuracy, treatment planning, and patient outcomes. Studies have shown improved accuracy and efficiency of AI models in the detection and treatment of prostate cancer, but further research is needed to understand its full potential as well as limitations.

Surgical gestures as a method to quantify surgical performance and predict patient outcomes

How well a surgery is performed impacts a patient's outcomes; however, objective quantification of performance remains an unsolved challenge. Deconstructing a procedure into discrete instrument-tissue "gestures" is a emerging way to understand surgery. To establish this paradigm in a procedure where performance is the most important factor for patient outcomes, we identify 34,323 individual gestures performed in 80 nerve-sparing robot-assisted radical prostatectomies from two international medical centers. Gestures are classified into nine distinct dissection gestures (e.g., hot cut) and four supporting gestures (e.g., retraction). Our primary outcome is to identify factors impacting a patient's 1-year erectile function (EF) recovery after radical prostatectomy. We find that less use of hot cut and more use of peel/push are statistically associated with better chance of 1-year EF recovery. Our results also show interactions between surgeon experience and gesture types-similar gesture selection resulted in different EF recovery rates dependent on surgeon experience. To further validate this framework, two teams independently constructe distinct machine learning models using gesture sequences vs. traditional clinical features to predict 1-year EF. In both models, gesture sequences are able to better predict 1-year EF (Team 1: AUC 0.77, 95% CI 0.73-0.81; Team 2: AUC 0.68, 95% CI 0.66-0.70) than traditional clinical features (Team 1: AUC 0.69, 95% CI 0.65-0.73; Team 2: AUC 0.65, 95% CI 0.62-0.68). Our results suggest that gestures provide a granular method to objectively indicate surgical performance and outcomes. Application of this methodology to other surgeries may lead to discoveries on methods to improve surgery.

Using Real-time Feedback To Improve Surgical Performance on a Robotic Tissue Dissection Task

Background

There is no standard for the feedback that an attending surgeon provides to a training surgeon, which may lead to variable outcomes in teaching cases.

Objective

To create and administer standardized feedback to medical students in an attempt to improve performance and learning.

Design setting and participants

A cohort of 45 medical students was recruited from a single medical school. Participants were randomly assigned to two groups. Both completed two rounds of a robotic surgical dissection task on a da Vinci Xi surgical system. The first round was the baseline assessment. In the second round, one group received feedback and the other served as the control (no feedback).

Outcome measurements and statistical analysis

Video from each round was retrospectively reviewed by four blinded raters and given a total error tally (primary outcome) and a technical skills score (Global Evaluative Assessment of Robotic Surgery [GEARS]). Generalized linear models were used for statistical modeling. According to their initial performance, each participant was categorized as either an innate performer or an underperformer, depending on whether their error tally was above or below the median.

Results and limitations

In round 2, the intervention group had a larger decrease in error rate than the control group, with a risk ratio (RR) of 1.51 (95% confidence interval [CI] 1.07-2.14; p = 0.02). The intervention group also had a greater increase in GEARS score in comparison to the control group, with a mean group difference of 2.15 (95% CI 0.81-3.49; p < 0.01). The interaction effect between innate performers versus underperformers and the intervention was statistically significant for the error rates, at F(1,38) = 5.16 (p = 0.03). Specifically, the intervention had a statistically significant effect on the error rate for underperformers (RR 2.23, 95% CI 1.37-3.62; p < 0.01) but not for innate performers (RR 1.03, 95% CI 0.63-1.68; p = 0.91).

Conclusions

Real-time feedback improved performance globally compared to the control. The benefit of real-time feedback was stronger for underperformers than for trainees with innate skill.

Patient summary

We found that real-time feedback during a training task using a surgical robot improved the performance of trainees when the task was repeated. This feedback approach could help in training doctors in robotic surgery.

SCiPad: evaluating telemedicine via iPad facetime for general spinal cord injury care

Study design

Uncontrolled clinical pilot study.

Objectives

To assess usage, perceived impact, and satisfaction with a telemedicine program among individuals with spinal cord injury (tele-SCI).

Setting

Community-based.

Methods

Participants (N = 83) were recruited from acute SCI inpatient rehabilitation and outpatient SCI care at a community hospital to participate in a 6-month tele-SCI intervention administered by SCI subspecialty board-certified physiatrists via iPad FaceTime. In addition to monthly follow up interview calls, psychosocial and Quality of Life (QoL) measures were collected at baseline and post-intervention. A program satisfaction survey was also collected post-intervention.

Results

Seventy-five percent of participants engaged in tele-SCI visits (Median [IQR]: 2.5 [2.0, 4.0]) for a total of 198 tele-SCI visits. Bladder and bowel concerns were the leading topics discussed during tele-SCI visits, followed by neurological, pain, and functional concerns. Tele-SCI users resided further away (Median miles [IQR] – 114[73–177] vs. 81[46–116], p = 0.023) and reported seeking more clinical advice (Median [IQR] – 1.5[0–4.0] vs. 0[0–1.0], p = 0.002) compared to non-tele-SCI users. All other clinical utilization, baseline characteristics, psychosocial measures, and QoL did not differ among those who used tele-SCI and those who did not. The satisfaction survey suggested satisfaction with the tele-SCI intervention (89%), study equipment (89%), staff responsiveness (100%), and improved motivation for self-monitoring of health (71%).

Conclusion

Study findings suggest that tele-SCI is a feasible modality for providing general SCI care. Further research is required to examine longer-term efficacy of remotely-provided care among individuals living with SCI.

The usage of calcium phosphate systems for onsite defluoridation treatment

Over 200 million people in over 35 countries are affected by excessive fluoride in their waters. For people that do not have access to a centralized water treatment plant, there is a need for an on-site defluoridation system that requires no special operational expertise, does not use hazardous chemicals, and is sustainable by the local population. 8 different calcium phosphate precipitation systems were analyzed and tested for fluoride removal effectiveness. An effective system would have final fluoride concentrations less than 1.5 mg/L and final solutions with pH within drinkable limits. Phosphoric acid with the addition of a calcium carbonate source was found to have a 99.8% fluoride removal rate. Monosodium phosphate with addition of slaked lime was also found to be effective with a 99.98% fluoride removal rate. An optimal slaked lime to monosodium phosphate ratio that achieved effective fluoride removal and neutral pH was found. With 0.45 g of Ca(OH)₂ and 1 g of NaH₂PO₄, initial fluoride concentrations up to 100 mg/L or more could be reduced to near zero concentrations, and a volume of approximately 337 mL of water with a concentration of 5 mg/L F^- could to be reduced to less than 1.5 mg/L F^-.

Abstract 2247: Genomic heterogeneity in the aqueous humor cell-free DNA in a patient with bilateral retinoblastoma

Purpose: Germline alterations in the RB1 tumor suppressor gene predispose patients to developing retinoblastoma (RB) in both eyes. However, tumors in bilateral RB may not respond identically to treatment. The additional genomic events that occur independently in each eye during tumorigenesis are not well characterized. The aqueous humor (AH) provides a novel source of cell-free tumor-derived DNA (ctDNA) for liquid biopsy, enabling the in vivo study of RB tumors. In this case report, we use our AH liquid biopsy to compare genomic profiles between the right and left eyes of a single patient with heritable RB while also showing that ctDNA longitudinal dynamics correspond to therapeutic response.

Methods: One patient with bilateral RB was included. Multiple samples of AH were obtained from each eye during routine intravitreal melphalan therapy and following enucleation of the left eye. Routine clinical blood testing was performed to determine germline RB1 status. CtDNA was isolated from the AH and sequenced on an Illumina platform to assess genome-wide somatic copy number alterations (SCNAs). The same sequencing libraries were used to identify somatic RB1 pathogenic variants using a custom hybridization and next generation sequencing panel targeting RB1. Tumor fraction (TFx) was estimated using ichorCNA software.

Results: Five AH samples from both eyes (3 from the right eye and 2 from the left eye) were included. Peripheral blood RB1 testing detected germline 13q and 16p deletions. Targeted RB1 mutational analysis of AH ctDNA identified a different somatic RB1 mutation in each eye. At initial AH sampling, three SCNAs were present in the right eye and these same SCNAs persisted in further samples. Two SCNAs were initially detected in the left eye and were consistently identified in later sampling. Despite the same germline RB1 mutation, the second somatic mutation was different in each eye and there were distinct, non-overlapping patterns of SCNAs in each eye. In addition, the right eye demonstrated a progressive decrease in TFx corresponding with therapeutic responsiveness and ocular salvage. The left eye had persistently larger TFx values and required enucleation due to tumor recurrence.

Conclusions: Our AH liquid biopsy detected distinct genomic events between eyes in a patient with bilateral RB and TFx changes corresponding with disease activity. Identifying inter-eye genomic heterogeneity without the need for enucleated tumor tissue may help direct active management of RB, with particular usefulness in bilateral cases.

Citation Format: Elyssa Y. Wong, Liya Xu, Lishuang Shen, Mary E. Kim, Ashley Polski, Rishvanth K. Prabakar, Rachana Shah, Rima Jubran, Jonathan W. Kim, Jaclyn A. Biegel, Xiaowu Gai, Peter Kuhn, James Hicks, Jesse L. Berry. Genomic heterogeneity in the aqueous humor cell-free DNA in a patient with bilateral retinoblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2247.

Antiretroviral Adherence, Drug Resistance, and the Impact of Social Determinants of Health in HIV-1 Patients in the US

Adherence to antiretroviral therapy (ART) is critical to achieving viral suppression. However, social determinants of health (SDoH) can undermine patient adherence to ART, resulting in drug resistance that compromises future treatment options. We assessed ART adherence and HIV-1 drug resistance at the national and state levels in the US and investigated their associations with SDoH and other HIV-related outcomes. Data were obtained from Symphony Health's Integrated Dataverse (IDV), Monogram/LabCorp Database, as well as national and publicly available databases, including Centers for Disease Control and Prevention (CDC), American Community Survey (ACS), and J. Kaiser Family Foundation (KFF). Inferential analyses were performed to investigate associations using patient-level data, and the results were reported by state and overall within the nation. Correlations between continuous variables were estimated by the Spearman's test, and that between continuous variable and categorical variable were estimated using one-way analysis of variance (ANOVA). State-level rates of poor adherence and resistance ranged from 26 to 55% and 20 to 54%, respectively. Female gender, non-white race, low education, poverty, and unemployment were associated with poor adherence; female gender was associated with drug resistance. Both adherence and resistance were correlated to HIV prevalence rates. Our findings suggest that US patients living with HIV face great challenges associated with poor ART adherence and HIV-1 drug resistance.

Advancing microarray assembly with acoustic dispensing technology

In the assembly of microarrays and microarray-based chemical assays and enzymatic bioassays, most approaches use pins for contact spotting. Acoustic dispensing is a technology capable of nanoliter transfers by using acoustic energy to eject liquid sample from an open source well. Although typically used for well plate transfers, when applied to microarraying, it avoids the drawbacks of undesired physical contact with the sample; difficulty in assembling multicomponent reactions on a chip by readdressing, a rigid mode of printing that lacks patterning capabilities; and time-consuming wash steps. We demonstrated the utility of acoustic dispensing by delivering human cathepsin L in a drop-on-drop fashion into individual 50-nanoliter, prespotted reaction volumes to activate enzyme reactions at targeted positions on a microarray. We generated variable-sized spots ranging from 200 to 750 microm (and higher) and handled the transfer of fluorescent bead suspensions with increasing source well concentrations of 0.1 to 10 x 10(8) beads/mL in a linear fashion. There are no tips that can clog, and liquid dispensing CVs are generally below 5%. This platform expands the toolbox for generating analytical arrays and meets needs associated with spatially addressed assembly of multicomponent microarrays on the nanoliter scale.

Dust and chemical exposures, and miscarriage risk among women textile workers in Shanghai, China

INTRODUCTION

To investigate possible associations between miscarriage and occupational exposures in the Shanghai textile industry.

METHODS

A retrospective cohort study of miscarriages among 1752 women in the Shanghai textile industry was conducted. Reproductive history was self-reported by women and occupational work histories were collected from factory personnel records. Occupational exposures were assigned by linking work history information to an industry-specific job-exposure matrix informed by factory-specific textile process information and industrial hygiene assessments. Estimates of cotton dust and endotoxin exposure were also assigned. Odds ratios (OR) and 95% CI were estimated by multivariate logistic regression, with adjustment for age at pregnancy, educational level, smoking status of the woman and her spouse, use of alcohol, and woman's year of birth.

RESULTS

An elevation in risk of a spontaneously aborted first pregnancy was associated with exposure to synthetic fibres (OR 1.89, 95% CI 1.20 to 3.00) and mixed synthetic and natural fibres (OR 3.31, 95% CI 1.30 to 8.42). No increased risks were observed for women working with solvents, nor were significant associations observed with quantitative cotton dust or endotoxin exposures. Associations were robust and similar when all pregnancies in a woman's reproductive history were considered.

CONCLUSIONS

Occupational exposure to synthetic fibres may cause miscarriages, and this possibility should be the subject of further investigation.

Enzyme microarrays assembled by acoustic dispensing technology

Miniaturizing bioassays to the nanoliter scale for high-throughput screening reduces the consumption of reagents that are expensive or difficult to handle. Through the use of acoustic dispensing technology, nanodroplets containing 10 microM ATP (3 microCi/microL (32)P) and reaction buffer in 10% glycerol were positionally dispensed to the surface of glass slides to form 40-nL compartments (100 droplets/slide) for Pim1 (proviral integration site 1) kinase reactions. The reactions were activated by dispensing 4 nL of various levels of a pyridocarbazolo-cyclopentadienyl ruthenium complex Pim1 inhibitor, followed by dispensing 4 nL of a Pim1 kinase and peptide substrate solution to achieve final concentrations of 150 nM enzyme and 10 microM substrate. The microarray was incubated at 30 degrees C (97% R(h)) for 1.5 h. The spots were then blotted to phosphocellulose membranes to capture phosphorylated substrate. With phosphor imaging to quantify the washed membranes, the assay showed that, for doses of inhibitor from 0.75 to 3 microM, Pim1 was increasingly inhibited. Signal-to-background ratios were as high as 165, and average coefficients of variation for the assay were approximately 20%. Coefficients of variation for dispensing typical working buffers were under 5%. Thus, microarrays assembled by acoustic dispensing are promising as cost-effective tools that can be used in protein assay development.

Reproductive history, occupational exposures, and thyroid cancer risk among women textile workers in Shanghai, China

OBJECTIVES

Thyroid cancer risk has been previously associated with increased age at first pregnancy and history of miscarriage. Occupational risk factors for thyroid cancer, with the exception of radioactive iodine, have not been well investigated. We conducted a case-cohort study nested in a cohort of 267,400 female textile workers in Shanghai, China, who had been followed for cancer incidence during 1989-1998.

METHODS

The analysis included 130 incident thyroid cases and 3,187 subcohort non-cases. Reproductive history was determined by questionnaire at baseline. Historical exposures were reconstructed from work history and information on factory processes and exposures. Cox proportional hazards analysis was performed to estimate hazard ratios (HR) for reproductive factors and occupational exposures.

RESULTS

Associations were observed between thyroid cancer and employment in jobs with 10 or more years of benzene exposure (HR 6.43, 95% CI: 1.08, 38) and formaldehyde exposure (HR 8.33, 95% CI: 1.16, 60). Administration workers also had an increased risk (HR 1.56, 95% CI: 1.08, 2.25). No associations between examined reproductive factors and thyroid cancer were observed in this study.

CONCLUSIONS

Despite statistically imprecise risk estimates, the findings suggest potential associations with some occupational chemical exposures in this cohort of textile workers.

Comparative risk and policy analysis in environmental health

There is increasing interest in the integration of quantitative risk analysis with benefit-cost and cost-effectiveness methods to evaluate environmental health policy making and perform comparative analyses. However, the combined use of these methods has revealed deficiencies in the available methods, and the lack of useful analytical frameworks currently constrains the utility of comparative risk and policy analyses. A principal issue in integrating risk and economic analysis is the lack of common performance metrics, particularly when conducting comparative analyses of regulations with disparate health endpoints (e.g., cancer and noncancer effects or risk-benefit analysis) and quantitative estimation of cumulative risk, whether from exposure to single agents with multiple health impacts or from exposure to mixtures. We propose a general quantitative framework and examine assumptions required for performing analyses of health risks and policies. We review existing and proposed risk and health-impact metrics for evaluating policies designed to protect public health from environmental exposures, and identify their strengths and weaknesses with respect to their use in a general comparative risk and policy analysis framework. Case studies are presented to demonstrate applications of this framework with risk-benefit and air pollution risk analyses. Through this analysis, we hope to generate discussions regarding the data requirements, analytical approaches, and assumptions required for general models to be used in comparative risk and policy analysis.

Acute epiglottitis in adults: the Royal Melbourne Hospital experience

BACKGROUND

To examine the common presentations and management of acute epiglottitis in adults.

METHOD

Retrospective clinical study of 17 consecutive adult patients who presented to the Royal Melbourne Hospital between January 1988 and December 2000 was undertaken.

RESULTS

The mean patient age was 47 years (range 20-87 years) and the male-to-female ratio was 1.8 : 1.0. Peak incidence occurred in September during early spring. All patients presented with sore throat and dysphagia; however, respiratory distress was only noted in 65%. The most common signs were temperature and tachycardia. Four patients (23%) required endotracheal intubation, which was performed electively in three and as an emergency in one. Three of 14 blood cultures were positive, two yielded Haemophilus influenzae type b and one yielded Streptococcus mitis. One of the four throat cultures was positive for Haemophilus influenzae type b. Twelve patients underwent awake flexible laryngoscopy under topical anaesthetic as part of their initial assessment, and there were no complications associated with this procedure. There was no mortality.

CONCLUSIONS

The diagnosis of acute epiglottitis in the adult population is difficult as respiratory distress may be absent. Patients who have a significant sore throat with no obvious aetiology should have direct visualization of their larynx by flexible laryngoscopy. Lateral X-ray of neck is of limited value. Once diagnosed, these patients should be hospitalized and monitored as airway obstruction may develop rapidly.

Cooperation, cost control and consumer focus are critical challenges for health care

As we move into the 21st Century, the U.S. health care system faces tremendous challenges such as care for an aging and increasingly diverse population, escalating costs and limited resources. Government, consumers, hospitals and the insurance industry are positioning themselves for the future. Physicians need to do the same. Physicians must come to the table and assert leadership by working collaboratively with major stakeholders. Examine some steps that need to be taken to help shape the future of medicine.

Enhancement of contrast echocardiography by image variability analysis

BACKGROUND

Although there have been recent advances in echocardiography, many studies remain suboptimal due to poor image quality and unclear blood-myocardium border. We developed a novel image processing technique, cardiac variability imaging (CVI), based on the variance of pixel intensity values during passage of ultrasound microbubble contrast into the left ventricle chamber, with the aim of enhancing endocardial border delineation and image quality.

METHODS AND RESULTS

CVI analysis was performed on simulated data to test and verify the mechanism of image enhancement. Then CVI analysis was applied to echocardiographic images obtained in two different clinical studies, and still images were interpreted by expert reviewers. In the first study (N = 15), using contrast agent EchoGen, the number of observable wall segments in end-diastolic images, for example, was significantly increased by CVI (4.93) as compared to precontrast (3.28) and contrast images (3.36), P < 0.001 for both comparisons to CVI. In the second study (N = 8), using contrast agent Optison, interobserver variability of manually traced end-diastolic volumes was significantly decreased using CVI (22.3 ml) as compared to precontrast (63.4) and contrast images (49.0), P < 0.01 for both comparisons to CVI.

CONCLUSION

CVI can substantially enhance endocardial border delineation and improve echocardiographic image quality and image interpretation.

Scedosporium endophthalmitis: two fatal disseminated cases of Scedosporium infection presenting with endophthalmitis

The incidence of disseminated infection with Scedosporium species is increasing in patients with haematological malignancy. Two fatal cases are reported of patients with acute myeloid leukaemia and neutropenia who presented with Scedosporium endophthalmitis. Diagnosis of fungal infection was delayed as blood and vitreous cultures were positive only after 3 days in patient 1 and blood culture was positive at 7 days in patient 2. Despite antifungal therapy with amphotericin B and additional fluconazole in patient 2, both patients died of overwhelming fungal septicaemia. Post-mortem examination of the right globe in patient 1 showed haemorrhagic necrotizing chorioretinitis with numerous fungal hyphae in choroidal vessels, choroid, retina and vitreous. Scedosporium species are often resistant to conventional antifungal therapy including amphotericin B. Diagnosis is difficult and mortality in disseminated infection is high.

Konjac-Mannan and American ginsing: emerging alternative therapies for type 2 diabetes mellitus

Despite significant achievements in treatment modalities and preventive measures, the prevalence of diabetes has risen exponentially in the last decade. Because of these limitations there is a continued need for new and more effective therapies. An increasing number of people are using dietary and herbal supplements, even though there is a general lack of evidence for their safety and efficacy. Consequently, science based medical and government regulators are calling for more randomized clinical studies to provide evidence of efficacy and safety. Our research group has selected two such promising and functionally complementary therapies for further investigation as potentially emerging alternative therapies for type 2 diabetes: Konjac-mannan (KJM) and American ginseng (AG). We have generated a mounting body of evidence to support the claim that rheologically-selected, highly-viscous KJM, and AG with a specific composition may be useful in improving diabetes control, reducing associated risk factors such as hyperlipidemia and hypertension, and ameliorating insulin resistance. KJM has a demonstrated ability to modulate the rate of absorption of nutrients from the small bowel, whereas AG has post-absorptive effects. Consequently, it appears that KJM and AG are acting through different, yet complementary, mechanisms: KJM by increasing insulin sensitivity and AG likely by enhancing insulin secretion. Before the therapeutic potential of KJM and AG as novel prandial agents for treatment of diabetes can be fully realized, further controlled trials with larger sample sizes and of longer duration are required. A determination of the active ingredients in AG, and the rheology-biology relationship of KJM are also warranted.

Quality adjusted life years (QALYs) and dose-response models in environmental health policy analysis -- methodological considerations

Analyses of competing risks are currently limited by the lack of empirically well-founded and generalizable quantitative methods. Specifically, quantitative methods for comparative risk analysis require the consideration of the population impacted, the duration of impact, the health endpoints at risk, and the impact on individual quality of life. Whereas risk analysis can be used to provide quantitative estimates of disease incidence, environmental health policy analyses do not often account for differences in health impact from alternative disease states. We discuss the methodological issues related to the use of quality adjusted life years (QALY) as a metric for normalizing expected disease incidence to account for health impact. Through a case study of the risks and benefits of fish consumption, we demonstrate the use of QALY weights with dose-response models for environmental health policy decision making. We suggest that, although this approach can be generalized for use in comparative risk and health policy analysis, it is informationally intensive and requires additional assumptions to those used in traditional safety/risk assessment.

Promoting the advancement of minority women faculty in academic medicine: the National Centers of Excellence in Women's Health

Minority physicians provide care in a manner that promotes patient satisfaction and meets the needs of an increasingly diverse U.S. population. In addition, minority medical school faculty bring diverse perspectives to research and teach cross-cultural care. However, men and women of color remain underrepresented among medical school faculty, particularly in the higher ranks. National data show that although the numbers of women in medicine have increased, minority representation remains essentially static. Studying minority women faculty as a group may help to improve our understanding of barriers to diversification. Six National Centers of Excellence in Women's Health used a variety of approaches in addressing the needs of this group. Recommendations for other academic institutions include development of key diversity indicators with national benchmarks, creation of guidelines for mentoring and faculty development programs, and support for career development opportunities.

Regulation of tight junction permeability and occludin phosphorylation by Rhoa-p160ROCK-dependent and -independent mechanisms

In epithelial and endothelial cells, tight junctions regulate the paracellular permeability of ions and proteins. Disruption of tight junctions by inflammation is often associated with tissue edema, but regulatory mechanisms are not fully understood. Using ECV304 cells as a model system, lysophosphatidic acid and histamine were found to increase the paracellular permeability of the tracer horseradish peroxidase. Cytoskeletal changes induced by these agents included stimulation of stress fiber formation and myosin light chain phosphorylation. Additionally, occludin, a tight junction protein, was a target for signaling events triggered by lysophosphatidic acid and histamine, events that resulted in its phosphorylation. A dominant-negative mutant of RhoA, RhoA T19N, or a specific inhibitor of Rho-activated kinases, Y-27632, prevented stress fiber formation, myosin light chain phosphorylation, occludin phosphorylation, and the increase in tracer flux in response to lysophosphatidic acid. In contrast, although RhoA T19N and Y-27632 blocked the cytoskeletal events induced by histamine, they had no effect on the stimulation of occludin phosphorylation or increased tracer flux, indicating that occludin phosphorylation may regulate tight junction permeability independently of cytoskeletal events. Thus, occludin is a target for receptor-initiated signaling events regulating its phosphorylation, and this phosphorylation may be a key regulator of tight junction permeability.

Women in physical medicine and rehabilitation. Leadership issues

Academic medical centers share the triple missions of education, research, and clinical care, particularly in vulnerable populations. They are well positioned to have a significant impact on reducing health disparities between patients from diverse backgrounds, both now and in future generations. A key component to realizing this goal lies in increasing the number of women in academic medicine. Women bring a fresh perspective to the investigative process, often targeting gender is a better way of providing preventive services, and patient satisfaction studies have shown that many patients prefer women physicians.

Cytodiagnosis of bronchogenic carcinoma and neuroendocrine tumor of the lung by transthoracic fine-needle aspiration

To evaluate our experience with the cytodiagnosis of primary lung cancers by transthoracic fine-needle aspiration (TFNA), 106 bronchogenic carcinomas (BC) and 6 neuroendocrine tumors of the lung (NTL) with adequate needle aspirates were reviewed. The cytodiagnostic accuracy rates of BCs were 75.5%, 72%, 100%, 53%, and 50% for bronchogenic adenocarcinomas, squamous-cell carcinomas, small-cell carcinomas, large-cell carcinomas, and mixed carcinomas, respectively. Of the 6 NTLs, 4 typical carcinoid tumors (CT) were correctly diagnosed, 1 atypical CT was wrongly identified as small-cell carcinoma, and 1 large-cell NTL was mistaken for an adenocarcinoma.

Adult proxy responses to a survey of children's dermal soil contact activities

Contaminated site cleanup decisions may require estimation of dermal exposures to soil. Telephone surveys represent one means of obtaining relevant activity pattern data. The initial Soil Contact Survey (SCS-I), which primarily gathered information on the activities of adults, was conducted in 1996. Data describing adult behaviors have been previously reported. Results from a second Soil Contact Survey (SCS-II), performed in 1998-1999 and focused on children's activity patterns, are reported here. Telephone surveys were used to query a randomly selected sample of U.S. households. A randomly chosen child, under the age of 18 years, was targeted in each responding household having children. Play activities as well as bathing patterns were investigated to quantify total exposure time, defined as activity time plus delay until washing. Of 680 total survey respondents, 500 (73.5%) reported that their child played outdoors on bare dirt or mixed grass and dirt surfaces. Among these "players," the median reported play frequency was 7 days/week in warm weather and 3 days/week in cold weather. Median play duration was 3 h/day in warm weather and 1 h/day in cold weather. Hand washes were reported to occur a median of 4 times per day in both warm and cold weather months. Bath or shower median frequency was seven times per week in both warm and cold weather. Finally, based on clothing choice data gathered in SCS-I, a median of about 37% of total skin surface is estimated to be exposed during young children's warm weather outdoor play.

An optical system for wireless detuning of parallel resonant circuits

A new optical method of detuning parallel resonant circuits is described. This method involves the integration of a photoresistor in parallel with the inductor and capacitor of a parallel resonant circuit, in this case a magnetic resonance imaging (MRI) receiver coil. A fiberoptic cable extending the length of the interventional device is used in conjunction with an external light source to deliver light to the photoresistor. Exposing the photoresistor to light changes its bulk resistance and greatly lowers the Q of the parallel resonant circuit, effectively detuning it. By combining this optical detuning scheme with inductive coupling of the interventional device-mounted microcoils to a standard MRI coil, a completely wireless device for active device tracking has been created. This new device improves on current technology by simplifying device complexity and reducing patient risk by eliminating the need for electrical connections between the device-mounted microcoils to the MR receiver channel.

Use of quality-adjusted life year weights with dose-response models for public health decisions: a case study of the risks and benefits of fish consumption

Risks associated with toxicants in food are often controlled by exposure reduction. When exposure recommendations are developed for foods with both harmful and beneficial qualities, however, they must balance the associated risks and benefits to maximize public health. Although quantitative methods are commonly used to evaluate health risks, such methods have not been generally applied to evaluating the health benefits associated with environmental exposures. A quantitative method for risk-benefit analysis is presented that allows for consideration of diverse health endpoints that differ in their impact (i.e., duration and severity) using dose-response modeling weighted by quality-adjusted life years saved. To demonstrate the usefulness of this method, the risks and benefits of fish consumption are evaluated using a single health risk and health benefit endpoint. Benefits are defined as the decrease in myocardial infarction mortality resulting from fish consumption, and risks are defined as the increase in neurodevelopmental delay (i.e., talking) resulting from prenatal methylmercury exposure. Fish consumption rates are based on information from Washington State. Using the proposed framework, the net health impact of eating fish is estimated in either a whole population or a population consisting of women of childbearing age and their children. It is demonstrated that across a range of fish methylmercury concentrations (0-1 ppm) and intake levels (0-25 g/day), individuals would have to weight the neurodevelopmental effects 6 times more (in the whole population) or 250 times less (among women of child-bearing age and their children) than the myocardial infarction benefits in order to be ambivalent about whether or not to consume fish. These methods can be generalized to evaluate the merits of other public health and risk management programs that involve trade-offs between risks and benefits.

Vascular endothelial growth factor stimulates dephosphorylation of the catenins p120 and p100 in endothelial cells

Vascular endothelial growth factor (VEGF) is an endothelium-specific mitogen that induces angiogenesis and increases vascular permeability. These processes involve regulation of cell-cell adhesion, but molecular mechanisms have yet to be fully established. p120, also termed p120(ctn), and its variant p100 are catenins which associate with cadherins and localize to adherens junctions. VEGF was reported to stimulate tyrosine phosphorylation of catenins in endothelial cells. In contrast, we have found that VEGF potently stimulated a rapid and dose-dependent decrease in serine/threonine phosphorylation of p120 and p100. VEGF acted via VEGF receptor 2 to achieve this effect which was independent of activation of the extracellular-signal-regulated kinase pathway. Histamine and activators of protein kinase C had a very similar effect to that of VEGF on phosphorylation of p120 and p100, suggesting that these diverse stimuli may converge on a common signalling element regulating p120/p100 serine/threonine phosphorylation. These data raise the possibility that the dephosphorylation of p120 and p100 triggered by VEGF may contribute to mechanisms regulating permeability and/or motility through modulation of cadherin adhesiveness.

Gene expressions during the development and sexual differentiation of the olfactory bulb in rats

In this study, expressions of cell-cycle-related genes: p53, retinoblastoma (Rb), p21, bcl-2(alpha), bcl-2(beta); protooncogene c-ski; glial cell marker protein gene S100beta; neurotransmitter gene, substance P and sexual-differentiation-related genes, androgen receptor (AR) and estrogen receptor beta (ER(beta)), are studied in the olfactory bulb of groups of both six female and six male rats at the ages of 3, 10, 20 and 40 days. Expressions of housekeeping genes such as beta-actin, cyclophilin and proliferating cell nuclear antigens (PCNA) are determined using reverse transcription polymerase chain reaction (RT-PCR) for the correction of unequal amount of cDNA added into the samples. Using labeled 32P-dCTP and Phosphorimager technology, relative abundance of radioactivities of the PCR products is obtained by dividing the radioactivity of each individual sample by the corresponding radioactivities of different housekeeping genes. Data evaluated by Two-way ANOVA indicate that only the bcl-2(alpha) gene expression is affected significantly by age, sex and their interactions no matter which of the three housekeeping genes is used for correction. When beta-actin was used for corrections, effects of age but not sex were found in the expressions of p53, Rb, p21, AR, ER(beta), substance P and S100beta genes, but not in bcl-2(beta), c-ski, cyclophilin and PCNA genes. While cyclophilin was used for corrections, only the p53, Rb, AR, ER(beta), substance P and S100beta but not the bcl-2(beta), p21, c-ski, PCNA and beta-actin genes are affected by age. They are all not influenced by sex of the animals. Only the AR, ER(beta) and S100beta genes are age-dependent when PCNA was used for the correction. The other gene expressions are not altered by sex, while the interactions of age and sex were found to be significantly affecting the bcl-2(beta) gene expression. Conclusively, developmental changes of the p53, Rb, AR, ER(beta), substance P and S100beta genes expressions are quite evidenced while only the bcl-2(alpha) gene seems to change significantly during the sexual differentiation of olfactory bulb in rats.

Fluorescence in situ hybridization (FISH) for detection of HER-2/neu amplification in breast cancer: a multicenter portability study

Amplification and/or overexpression of HER-2/neu has been shown to be both a prognostic and predictive marker in breast cancer. Recent studies have also confirmed the efficacy of Herceptin (trastuzumab) as adjuvant therapy for patients with overexpression of HER-2/neu. Therefore, it is critical that precise and reproducible assays be used in the clinical laboratory setting for determination of the HER-2/neu status in patients with breast cancer. The objective of this study was to determine the portability (reproducibility between different institutions) of the PathVysion HER-2 fluorescence in situ hybridization (FISH) assay used for detection of amplification of the HER-2/neu gene in formalin-fixed, paraffin-embedded tissue sections of invasive ductal carcinoma of the breast. Study specimens consisted of one breast tumor with a normal HER-2/neu copy number, two tumors with a low level, and one tumor with a high level of HER-2/neu amplification. The PathVysion HER-2 assay was shown to be highly reproducible on different assay days (n = 3) and between different institutions (n = 5) in the detection of amplification of the HER-2/neu gene in routinely processed clinical specimens of breast carcinoma. In addition, this study examined the feasibility of enumerating FISH signals in 20 nuclei in contrast to 60 nuclei per specimen. Although a modest increase in variation was observed when analyzing 20 compared to 60 nuclei, the mean ratios were similar. Therefore, analysis of as few as 20 nuclei with this FISH HER-2/neu assay may be sufficient for determining the amplification level of the HER-2/neu gene.

Phosphodiesterase 4 conformers: preparation of recombinant enzymes and assay for inhibitors

Cyclic nucleotides are key regulators of many cellular processes. Their immediate action is terminated through the activity of phosphodiesterases, a diverse family of enzymes. This diversity has given rise to drug discovery opportunities, and assay technology is therefore of key importance. Inhibitors of the cyclic-AMP-specific phosphodiesterases (the PDE4 family) are drug candidates for a variety of inflammatory disorders. However, PDE4 inhibitors, besides their immunomodulatory effects, also cause side effects including nausea and emesis. Recently, it has been suggested that PDE4 exists in two different conformations with respect to inhibition by the prototypical compound rolipram. Inhibition of the low-affinity conformer is thought to give rise to anti-inflammatory effects, and inhibition of the high-affinity conformer to side effects. Therefore, a selective inhibitor of the low-affinity conformer may have clinical utility. Methods are described to prepare recombinant forms of PDE4B that allow screening for compounds that could preferentially inhibit the low-affinity conformer. Furthermore, conditions for an efficient, scintillation proximity, microtiter plate-based assay are described, providing a considerable advance over previous assays in terms of throughput and automatability.

Cost effectiveness of transbronchial needle aspiration

OBJECTIVE

To evaluate the yield and cost effectiveness of transbronchial needle aspiration (TBNA) in the assessment of mediastinal and/or hilar lymphadenopathy.

DESIGN

Retrospective study.

SETTING

A university hospital.

POPULATION STUDIED

Ninety-six patients referred for bronchoscopy with computed tomographic evidence of significant mediastinal or hilar adenopathy.

RESULTS

Ninety-nine patient records were reviewed. Three patients had two separate bronchoscopy procedures. TBNA was positive in 42 patients (44%) and negative in 54 patients. Of the 42 patients with a positive aspirate, 40 had malignant cytology and two had cells consistent with benign disease. The positive TBNA result altered management in 22 of 40 patients with malignant disease and one of two patients with benign disease, thereby avoiding further diagnostic procedures. The cost of these subsequent procedures was estimated at $27,335. No complications related to TBNA were documented.

CONCLUSIONS

TBNA is a high-yield, safe and cost effective procedure for the diagnosis and staging of bronchogenic cancer.

Electron transfer processes in the reactivity of nonsteroidal anti-inflammatory drugs in the ground and excited states

The nonsteroidal anti-inflammatory drugs (NSAID), naproxen, sulindac and indomethacin, were shown to donate electrons to nitro blue tetrazolium (NBT) when irradiated with UV light in deoxygenated aqueous buffer solution (pH 7.4, 30 degrees C). The reaction was monitored spectrophotometrically by the appearance of the diformazan reduction product from NBT. The electron transfer process facilitates the decomposition of the drugs. Naproxen in the presence of NBT is photodegraded principally to the alcohol (2-[1-hydroxyethyl]-6-methoxynaphthalene) at a rate approximately 20-fold faster than when irradiated alone in deoxygenated conditions. The photoproduct from naproxen also participates in the electron transfer to NBT but at a much slower rate than naproxen. Irradiation of sulindac or indomethacin in the presence of NBT caused the slow photoreduction of NBT to diformazan. In the absence of NBT, indomethacin and sulindac are essentially unreactive when irradiated in aqueous solution. The ability of a number of NSAID to act as electron donors in their ground state was studied by observing their oxidation by potassium peroxodisulfate in pH 7.0 phosphate buffer at 50 degrees C. The HPLC analysis of the drug remaining showed that the 2-arylpropionic acid NSAID (naproxen, ibuprofen, ketoprofen and suprofen) reacted at a rate equivalent to the thermal decomposition of peroxodisulfate. The major products were the same as detected in the photooxidation of these drugs, resulting from decarboxylation and oxygen addition but also included a dimeric compound. On the other hand, the NSAID that do not contain the propionic acid substituent all reacted more slowly with peroxodisulfate, enabling specific reaction rate constants to be evaluated.

Reproducibility of LSI HER-2/neu SpectrumOrange and CEP 17 SpectrumGreen Dual Color deoxyribonucleic acid probe kit. For enumeration of gene amplification in paraffin-embedded specimens: a multicenter clinical validation study

Overexpression and/or amplification of HER-2/neu gene have been found to be prognostic and predictive in breast and other cancers. Fluorescence in situ hybridization (FISH) assay, with its sensitivity and specificity, can be a superior method of detection when its performance characteristics are demonstrated. A multicenter study was initiated to evaluate the reproducibility of the LSI HER-2/neu SpectrumOrange and CEP 17 SpectrumGreen Dual Color DNA Probe for enumeration of both the HER-2/neu gene and chromosome 17 (signals) in interphase cells. Section slides were prepared from four cell lines (H, E, R, and N) with known ratios of the HER-2/neu to CEP 17 copy numbers (approximately H = 1.10, E = 1.70, R = 4.50, N = 9.0). The study variable was the ratios of the HER-2/neu to chromosome 17 copy numbers. Reproducibility with respect to assay, site, lot, day and reader was evaluated at 3 centers. Out of 120 specimen slides, 100 percent were successfully assayed. There were no significant differences among: (1) four repeated assays of the same specimen (p = 0.99), (2) the four probe lots (p = 0.33), or (3) the four study days (p = 0.54). There was statistically significant, but not important differences among centers and between readers. The ratios of the HER-2/neu to chromosome 17 copy numbers were estimated with accuracy and precision; the mean ratios (and sd) for specimens, H, E, R, and N were 1.05 (0.06), 1.81 (0.12), 4.48 (0.28), and 8.60 (1.23), respectively. In summary, assays with the LSI HER-2/neu and CEP 17 Dual Color DNA Probe Kit, conducted at three sites by 6 different technicians, over 8 assay days, using kits from four lots, were performed with a high success rate in paraffin-embedded specimens. The signal enumeration was also accurate and precise. This study demonstrated that the results obtained by using the LSI HER-2/neu SpectrumOrange and CEP 17 SpectrumGreen Dual Color DNA Probe Kit are reliable and reproducible.

Effect of meal dilution on the postprandial glycemic response. Implications for glycemic testing

OBJECTIVE

To investigate the effect of varying the volume of sugar meals on the post-prandial glycemic response (PGR).

RESEARCH DESIGN AND METHODS

On six separate occasions, after an overnight fast, blood glucose concentrations were measured in eight healthy subjects (34 +/- 4 years of age, BMI 22.9 +/- 0.9 kg/m2) after the consumption of 25 g glucose, sucrose, or fructose dissolved in either 200 or 600 ml of water. Blood was obtained at fasting and then at times 15, 30, 45, 60, and 90 min after the start of the test meal.

RESULTS

PGR was found to be influenced by carbohydrate type (P < 0.001). Mean response areas (min.mmol.l-1) to the three sugars were statistically different (P < 0.05). Glucose had the highest response area (90.0 +/- 8.1), followed by sucrose (61.3 +/- 5.0) and then fructose (14.7 +/- 2.8). Independent of this effect, PGR was also found to be influenced by volume dose (P < 0.01). By tripling meal volume from 200 to 600 ml, PGR areas were significantly increased for all three sugars, glucose (79.3 +/- 10.3 vs. 100.8 +/- 12.0, P = 0.035), sucrose (52.6 +/- 5.5 vs. 70 +/- 7.4, P = 0.0094), and fructose (11.0 +/- 3.8 vs. 18.4 +/- 3.9, P = 0.012). Where the effects of time (P < 0.05) and dose (P < 0.05) were determined to be independent (interaction nonsignificant) for all three sugars, this increase in volume also significantly increased glycemic concentrations at 15 min, for glucose (P = 0.033) and sucrose (P = 0.026), suggesting that changes in gastric emptying time may be a mechanism of action.

CONCLUSIONS

Varying the volume of liquid sugar meals alters PGR. Understanding this concept may help to reduce variability both in the glycemic testing of foods and oral glucose tolerance testing.

Uterine didelphys and occult spinal dysraphism: an unusual case

This report describes a case of uterine didelphys, lipomeningocele, meatal stenosis, and inguinal hernia presenting in a single individual. This unusual group of birth defects suggests a common mechanism of malformation in tailbud maturation which involves both the müllerian duct and the distal spinal cord.

Diode laser contact transscleral cyclophotocoagulation for refractory glaucoma in Asian patients

PURPOSE

To evaluate the effectiveness and safety of diode laser contact transscleral cyclophotocoagulation in Asian patients with refractory glaucoma by lower energy settings with an innovative probe featuring a glass ball tip that focused the laser beam onto the ciliary body.

METHODS

This prospective clinical study included consecutive Asian patients with dark irides and confirmed for glaucoma. Only one eye of each patient was treated. Diode laser contact transscleral cyclophotocoagulation treatment was performed with the center of the probe placed 1.5 mm behind the limbus. About 30 pulses of 810-mm laser radiation (power, 1.8 to 2.0 W; duration, 0.3 to 0.5 second) were applied around the eye. Patients were examined at fixed postoperative intervals. Intraocular pressure levels and postoperative complications were recorded. The relation between patient and disease characteristics, total laser energy delivered, and intraocular pressure effects were analyzed.

RESULTS

Thirty-three patients were studied, with a mean follow-up period of 9.4 months. An average 56% of patients showed a 30% or greater drop in intraocular pressure. About 38% of patients achieved sustained intraocular pressure lowering to below 22 mm Hg at 18 months. Complications were few and included transient hypotony and iritis.

CONCLUSIONS

In Asian patients with refractory glaucoma or painful glaucomatous eyes with poor visual acuity (defined for this study as worse than 20/200), low-energy-setting diode laser contact transscleral cyclophotocoagulation by means of the glass ball probe is relatively effective and safe.

Analysis of photorefractive keratectomy patients who have not had PRK in their second eye

BACKGROUND AND OBJECTIVE

Excimer laser photorefractive keratectomy (PRK) is performed at the Singapore National Eye Centre (SNEC) with a minimum period of 3 months between first and second eye treatment. During this period, iatrogenic anisometropia may occur, which can lead to significant visual disability. We analyzed the reasons why some patients delayed or did not receive PRK treatment to their second eye. The reasons for originally electing PRK, and the expectations these patients had, were also studied.

PATIENTS AND METHODS

Between January 1992 and September 1993, 341 patients underwent PRK at SNEC. Of these, 86 (25.2%) did not receive PRK to their fellow eye within 1 year of follow-up and were recruited into the study. Data were collected retrospectively using a standardized questionnaire, and objective clinical data were obtained from the case records. Sixty-eight patients (79%) responded.

RESULTS

Fifty-one patients (14.9%) had not undergone PRK at the conclusion of the study (mean follow-up = 31 months). Of these, 36 were due to dissatisfaction with the results of the procedure. Symptoms relating to hypermetropia (15 patients) and symptoms of glare and halos were the main reasons which discouraged patients from receiving PRK in their fellow eye. Seventeen of the 51 patients (33.3%) who did not have PRK performed in the second eye were overcorrected to hypermetropia, as opposed to 9 out of 255 patients (3.5%) who had PRK in the second eye (P < 0.001, chi-square test). Seventy-five percent of the patients who did not undergo PRK in the second eye expected postlaser unaided vision to be equal to prelaser best corrected vision; however, only 23% of these patients achieved this.

CONCLUSION

Hypermetropia, glare and halos are significant causes of patient dissatisfaction after PRK. Patients who request PRK should be advised against harboring unrealistically high expectations for the procedure.

Cloning of an insecticidal cholesterol oxidase gene and its expression in bacteria and in plant protoplasts

We cloned and sequenced structural gene choM, which encodes an insecticidally active cholesterol oxidase in Streptomyces sp. strain A19249. The primary translation product was predicted to be a 547-amino-acid protein whose first 43 amino acids constitute a secretory signal peptide. Expression of the gene with the signal sequence in Escherichia coli resulted in production of a protein that had enzymatic and insecticidal properties which were indistinguishable from those of the cholesterol oxidase secreted by Streptomyces sp. strain A19249. Expression of the gene with or without the signal sequence in tobacco protoplasts resulted in production of an enzymatically active cholesterol oxidase.

Hospital pharmacy-based service for patient-controlled analgesia

A hospital pharmacy-based patient-controlled analgesia (PCA) service is described. The pharmacy department at a 255-bed community hospital instituted a comprehensive PCA service in 1985. Pharmacists were given thorough training in the clinical aspects of pain management and were taught how to use the PCA device; nurses also received instruction. An order for PCA is issued by a physician, who may then delegate decisions about medication choice, duration of therapy, and device settings to a clinical pharmacist. The pharmacist reviews the order and evaluates the patient's status. If PCA is appropriate, the pharmacist selects the analgesic agent and PCA device settings and prepares a pharmacy monitoring card. Orders for syringes are filled in the central pharmacy or by the decentralized pharmacist. Each order is entered into the i.v. drug profile and the i.v. drug computer file, and a narcotics control card is completed. The nurse programs the device, instructs the patient, and records the patient's level of pain control on a PCA-monitoring record. The pharmacist observes patients daily and records observations and changes on the pharmacy monitoring card. Use of the PCA service has grown from an average of 56 patient days per month in 1985 to 919 in 1989, and pharmacy department revenue has increased accordingly. A moderate increase in workload has been absorbed without the need for an increase in staff. Surveys show broad acceptance of the service by physicians, nurses, and patients. A hospital pharmacy-based PCA service offered patients better control of pain, allowed pharmacists to demonstrate competence in non-distributive functions, increased the visibility of the pharmacy department, and was a source of revenue.

Effects of temperature on Escherichia coli overproducing beta-lactamase or human epidermal growth factor

The effects of temperature on strains of Escherichia coli which overproduce and excrete either beta-lactamase or human epidermal growth factor were investigated. E. coli RB791 cells containing plasmid pKN which has the tac promoter upstream of the gene for beta-lactamase were grown and induced with isopropyl-beta-D-thiogalactopyranoside in batch culture at 37, 30, 25, and 20 degrees C. The lower temperature greatly reduced the formation of periplasmic beta-lactamase inclusion bodies, increased significantly the total amount of beta-lactamase activity, and increased the purity of extracellular beta-lactamase from approximately 45 to 90%. Chemostat operation at 37 and 30 degrees C was difficult due to poor cell reproduction and beta-lactamase production. However, at 20 degrees C, continuous production and excretion of beta-lactamase were obtained for greater than 450 h (29 generations). When the same strain carried plasmid pCU encoding human epidermal growth factor, significant cell lysis was observed after induction at 31 and 37 degrees C, whereas little cell lysis was observed at 21 and 25 degrees C. Both total soluble and total human epidermal growth factor increased with decreasing temperature. These results indicate that some of the problems of instability of strains producing high levels of plasmid-encoded proteins can be mitigated by growth at lower temperatures. Further, lower temperatures can increase for at least some secreted proteins both total plasmid-encoded protein formed and the fraction that is soluble.

Secretion and export of IGF-1 in Escherichia coli strain JM101

The processing of LamB-IGF-1 fusion protein and the export of processed IGF-1 (insulin-like growth-factor-1) into the growth medium was examined in the Escherichia coli host strain, JM101. Several strain or plasmid modifications were tried to increase export of periplasmic (processed) IGF-1 into the growth medium of JM101. These included: (1) use of a lon null mutant strain to increase accumulation levels of unprocessed LamB-IGF-1 fusion protein; (2) use of an alternative drug resistance marker on the expression plasmid rather than beta-lactamase, thereby reducing any competition for processing of LamB-IGF-1 by signal peptidase; (3) examination of whether phage M13 gene III protein expression caused more periplasmic IGF-1 to be exported into the growth medium due to increased outer membrane permeability; and (4) examination of the effect of E. coli or yeast optimized IGF-1 codons. None of these strain or plasmid modifications caused any significant increase in export of IGF-1 into the growth medium of JM101. Solubility studies of LamB-IGF-1 and processed IGF-1 showed that virtually all of the LamB-IGF-1 and IGF-1 remaining within the cell after a 2 h induction period was insoluble. This implied that only soluble LamB-IGF-1 was processed to IGF-1 and that only soluble IGF-1 was exported into the growth medium. Taken together, the results indicated that LamB-IGF-1 and IGF-1 solubility were the limiting factors in secretion of IGF-1 into the periplasm and export of IGF-1 into the growth medium.

Expression of secreted insulin-like growth factor-1 in Escherichia coli

The synthesis, processing and secretion of insulin-like growth factor-1 (IGF-1 or somatomedin-C) fused to LamB and OmpF secretion leader sequences in Escherichia coli have been investigated. Expression and secretion of IGF-1 was achieved. The major portion of this secreted IGF-1 accumulated in the periplasmic space as insoluble aggregates. A small amount of IGF-1 was found folded in its native conformation in the medium. The lamB and ompF signal sequences were fused to the 5' coding sequence of IGF-1. Fusion of the lamB signal sequence directly to IGF-1 (lamB-IGF-1) resulted in accumulation of 16-20 micrograms/A550/ml of correctly processed IGF-1 in the periplasmic space. The processing efficiency of LamB-IGF-1 and OmpF-IGF-1 was enhanced in an E. coli strain bearing a prlA4 mutation. Amino acid sequence analysis of IGF-1 secreted into the periplasm and exported into the medium confirmed the precise removal of the LamB or OmpF signal sequence. IGF-1 synthesized in E. coli was demonstrated to be active in a cell proliferation bioassay.

Mistranslation in IGF-1 during over-expression of the protein in Escherichia coli using a synthetic gene containing low frequency codons

Partial misincorporation of Lys for Arg has been observed for the Arg residues of IGF-1 when the molecule is expressed in Escherichia coli using a synthetic gene with the low frequency AGA codon encoding all six Arg residues and yeast preferred codons encoding the remaining residues. The Lys for Arg substitution at these residues could not be detected when a gene containing E. coli preferred codons, with the codon CGT coding for all Arg residues, was used for the expression of the protein. Similarly, no misincorporation of Lys for Arg could be detected when a gene containing Escherichia coli preferred codons at all positions, except for an AGA codon at Arg (36), was utilized.

Purification of recA-based fusion proteins by immunoadsorbent chromatography. Characterization of a major antigenic determinant of Escherichia coli recA protein

Monoclonal antibodies to Escherichia coli recA protein were prepared, characterized, and used as affinity reagents for the purification of recA and recA:somatostatin fusion proteins. The monoclonal antibodies recognize an antigenic determinant or determinants located between amino acids 260 and 330 of recA. Addition of a fragment of the recA gene coding for these amino acids to an unrelated gene (beta-galactosidase) allowed the resulting beta-galactosidase fusion protein to be recognized by the recA monoclonal antibodies.

Glucocorticoids inhibit the coordinated translation of alpha- and beta-globin mRNAs in Friend erythroleukemia cells

The dimethylsulfoxide (Me2SO)-mediated induction of hemoglobin synthesis in Friend erythroleukemia cells is inhibited by the glucocorticoids hydrocortisone, dexamethasone, and fluocinolone acetonide; hydrocortisone, at concentrations of 10(-5) to 10(-8) M inhibits by 90-30% and fluocinolone acetonide at concentrations of 10(-8) to 10(-11) M shows a greater than 90% inhibition. At these concentrations the hormones have no effect on cell growth or viability. In this study it has been shown that there is a group of proteins, including the alpha- and beta-globins, whose regulation is associated with the induction of Friend erythroleukemia cell differentiation, and that the expression of some of these, in addition to alpha- and beta-globin, is affected by glucocorticoids. The levels of alpha- and beta-globin mRNAs are very close to fully induced levels and preclude transcription as a major site for glucocorticoid control. In addition, it has been shown that glucocorticoids inhibit the translation of alpha- and beta-globin mRNAs, that the level of this inhibition is concentration dependent, and that the translation of beta-globin mRNA is slightly more sensitive to inhibition than the translation of alpha-globin mRNA. It is concluded that, although the translation of alpha- and beta-globin mRNA is a major site of inhibition by glucocorticoids, there is a detectable amount of alpha- and beta-globin synthesized. Thus, part of this mechanism may involve a differential sensitivity of alpha- and beta-globin mRNA translation which results in unequal amounts of globin synthesis and an overall more potent inhibition of hemoglobin formation.