Robotic Heller's cardiomyotomy for achalasia: early outcomes for a high-volume UK centre

INTRODUCTION

Heller's cardiomyotomy (HCM) is the gold standard treatment for achalasia. Laparoscopic HCM has been shown to be effective with low rates of symptom recurrence, though oesophageal mucosal perforation rates remain high. The aim of this prospective case series is to assess the short-term complication rates and perioperative outcomes for the first cohort of patients undergoing robotic-assisted HCM for achalasia in a single high-volume UK centre.

METHODS

Data were collected from a prospective cohort of patients who underwent robotic HCM at a single high-volume UK centre. Outcomes were assessed using the Eckhard score, which was calculated after their routine postoperative clinic appointments.

RESULTS

Thirteen patients underwent robotic HCM during the study period; this is the second largest reported case series in the European literature. There were no intraoperative oesophageal perforations. Six patients were discharged as day cases, six patients were discharged on the first postoperative day and one patient's hospital stay was two nights. There was a single perioperative complication of urinary retention. All patients reported improvement of symptoms following their operation, and all had a postoperative Eckhard score of less than 3, indicating their achalasia was in remission.

CONCLUSIONS

This cohort has demonstrated that robotic HCM has an exceptional safety profile and results in high levels of symptom resolution, even early in the learning curve. The robotic approach may be superior to laparoscopy as it allows more precise identification and dissection of the oesophageal muscle fibres, which likely reduces the risk of inadvertent mucosal damage or incomplete myotomy.

Melatonin for migraine prevention in children and adolescents: A randomized, double-blind, placebo-controlled trial after single-blind placebo lead-in

BACKGROUND

Melatonin is effective for migraine prevention in adults. We hypothesized that melatonin would also be effective for migraine prevention in children and adolescents.

METHODS

This was a randomized, double-blind trial of melatonin (3 mg or 6 mg) versus placebo for migraine prevention in 10-17 year-olds with 4-28/28 headache days at baseline. Participants were recruited from the UCSF Child & Adolescent Headache Program, UCSF child neurology clinic, and social media advertisements. Migraine diagnosis was confirmed by a headache specialist. Participants completed an 8-week single-blind placebo run-in. Those meeting randomization criteria (≥4 headache days and ≥23/28 electronic diary entries during weeks 5-8) were randomized 1:1:1 to placebo:melatonin 3 mg:melatonin 6 mg nightly for 8 weeks. The primary outcome measure was migraine days in weeks 5-8 of randomized treatment between melatonin (combined 6 mg + 3 mg) versus placebo. We aimed to enroll n = 210.

RESULTS

The study closed early due to slow enrollment (n = 72). Two participants were in the single-blind phase when the study closed, therefore the meaningful n = 70. Sixteen percent (11/70) were lost to follow-up during the single-blind phase. An additional 21% (15/70) did not meet randomization criteria (<4 headache days: n = 5, <23/28 diary days: n = 7, both: n = 3). Sixty-three percent (44/70) were eligible to randomize, of whom 42 randomized (n = 14 per arm). Taking another preventive at enrollment (OR 8.3, 95% CI 1.01 to 68.9) was the only variable associated with meeting randomization criteria. Of those randomized, 91% (38/42) provided diary data in the final 4-weeks. However, given the amount of missing data, only those with ≥21/28 diary days were analyzed-7/14 (50%) in the placebo group, and 20/28 (71%) in the melatonin groups combined. Median (IQR) migraine/migrainous days in weeks 5-8 of double-blind treatment was 2 (1-7) in the placebo group versus 2 (1-12) in the melatonin groups combined; the difference in medians (95% CI for the difference) was 0 days (-9 to 3). There were no differences in adverse events between groups.

CONCLUSIONS

When compared to recall at enrollment, headache days decreased across the single-blind placebo phase and the double-blind phase. There was no suggestion of superiority of melatonin; however, given the substantial portion of missing data, numerically higher in the placebo arm, and underpowering, this should not be interpreted as proof of inefficacy. Melatonin was generally well tolerated with no serious adverse events. Future migraine preventive trials in this age group may find this trial helpful for anticipating enrollment needs if using a single-blind placebo run-in. Enriching for those already on a migraine preventive may improve randomization rates in future trials, though would change the generalizability of results.

Outcomes That Matter to Adolescents With Continuous Headache Due to Chronic Migraine and Their Parents: A Pilot Survey Study

BACKGROUND

Children and adolescents with chronic migraine who have continuous headache may have high levels of headache-related disability but have largely been excluded from clinical trials. Understanding patient-valued treatment outcomes may facilitate future study design.

OBJECTIVE

To identify patient-valued outcome measures for headache preventive treatments among adolescents with continuous headache due to chronic migraine and their parents.

METHODS

Adolescents with an ICHD-3 diagnosis of chronic migraine, who had continuous headache and who were being cared for at a tertiary pediatric headache clinic, and their parents, were surveyed to query the value of treatment outcomes in the domains of headache frequency, intensity, functional impact, and associated symptoms. Individual outcomes and categories of outcomes were ranked in order of preference using weighted average rank. Results were rounded to the degree of precision with which they were measured.

RESULTS

The survey was completed by 55 adolescents and 60 parents of adolescents with continuous headache due to chronic migraine. Mean age of adolescents was 16 (SD 1, range 12 to 17). Median adolescent-reported duration of continuous headache was 24 months (IQR 12-39) and adolescents had tried a median (IQR) of 2 (0-5) preventive medications, only 13% of which were perceived as helpful. Overall, the most valued individual outcome measure among both adolescents and parents was a decrease in frequency of more severe headaches; however, outcomes reflecting headache intensity were most valued by adolescents while outcomes reflecting functional impact were most valued by parents. Over 60% of adolescents felt that it was more important to measure decrease in frequency and intensity of headaches in terms of severe headaches/spikes rather than total headache days. Among associated symptoms, improvement in "brain fog" was most highly valued by both adolescents and parents.

DISCUSSION

The results of this study provide important information about which preventive treatment outcomes are valued by adolescents with continuous headache due to chronic migraine and their parents. Results suggest that adolescents value a decrease in frequency of severe headaches over a decrease in frequency of headache days overall. Generalizability may be limited as the surveyed population were being cared for at a tertiary pediatric headache clinic and generally had headache disorders that were refractory to treatment. These results may help guide future trial design in this population with continuous headache due to chronic migraine.

TRIAL REGISTRATION

NA.

Acute and chronic management of posttraumatic headache in children: A systematic review

OBJECTIVES

The goal of this paper is to provide a compilation of the evidence for the treatment of posttraumatic headache (PTH) in the pediatric population. Headache features and timing of therapy were considered.

BACKGROUND

Headache is the most common symptom following mild traumatic brain injury (mTBI), affecting more than 80% of children and adolescents. It is unclear whether treatment for PTH should be tailored based on headache characteristics, particularly the presence of migraine features, and/or chronicity of the headache.

METHODS

Systematic literature searches of PubMed, Embase, Scopus, and Cochrane databases (1985-2021, limited to English) were performed, and key characteristics of included studies were entered into RedCAP^® (Prospero ID CRD42020198703). Articles and conference abstracts that described randomized controlled trials (RCTs), cohort studies, retrospective analyses, and case series were included. Participants included youth under 18 years of age with acute (<3 months) and persistent (≥3 months) PTH. Studies that commented on headache improvement in response to therapy were included.

RESULTS

Twenty-seven unique studies met criteria for inclusion describing abortive pharmacologic therapies (9), preventative pharmacotherapies (5), neuromodulation (1), procedures (5), physical therapy and exercise (6), and behavioral therapy (2). Five RCTs were identified. Studies that focused on abortive pharmacotherapies were completed in the first 2 weeks post-mTBI, whereas other treatment modalities focused on outcomes 1 month to over 1-year post-injury. Few studies reported on migrainous features (7), personal history of migraine (7), or family history of migraine (3).

CONCLUSIONS

There is limited evidence on the timing and types of therapies that are effective for treating PTH in the pediatric population. Prospective studies that account for headache characteristics and thoughtfully address the timing of therapies and outcome measurement are needed.

439 Managing Parathyroid Carcinoma in the Age of COVID 19

Aim

Parathyroid carcinoma is a rare malignancy accounting for 1% of cases of primary hyperparathyroidism. Pre-operative diagnosis is difficult because in the absence of metastatic disease, the presentation is similar to benign parathyroid disease. In patients with hyperparathyroidism and severe hypercalcaemia or a significantly raised parathyroid hormone (PTH) level clinicians should consider parathyroid carcinoma and expediting surgical management. During the current pandemic, a high index of suspicion should be maintained to ensure that care is not compromised. A review of the management of patients with suspected parathyroid carcinoma during the COVID-19 pandemic is presented.

Method

In our tertiary referral centre for Endocrine surgery, 4 presentations of parathyroid cancer were reviewed. Their investigations, surgical management and post-operative outcomes are described with a brief literature review of parathyroid cancer.

Results

Of the four cases of parathyroid carcinoma described, all presented with severe hypercalcaemia and significantly raised PTH levels. Pre-operative mean calcium was 3.36mmol/L and mean PTH was 80pmol/L (52-99.8). Patients were imaged with a combination of cross-sectional imaging and ultrasound. Two patients had evidence of distant disease at presentation. 1 patient was transferred as an inpatient to our centre and the other three patients were seen within 2 weeks of referral; the mean time from referral to surgery was 14days (1-23). Post-operatively, all patients achieved normocalcaemia, with PTH levels normal in all but one.

Conclusions

Despite limitations on face-to-face clinic consultations and reduced capacity for elective surgery during the COVID-19 pandemic, all patients were investigated and managed promptly to ensure superior outcomes.

1424 Enhanced Consent in Endocrine Surgery in The Era Of COVID-19

Aim

Informed consent is the process by which surgeon and patient agree to undergo a procedure after the risk, benefits and alternative treatments have been discussed. The current COVID-19 pandemic provides unique challenges to the consent process such as the uncertain risk of acquiring the virus and the impact of a second peak on the health services. The aim of this audit was to use an enhanced consent tool to inform patients of specific risks associated with surgery during the pandemic.

Method

At the beginning of the pandemic, elective operating was postponed - these patients were added to a COVID-19 database. With the resumption of services, all patients had a telephone clinic appointment with a 2-fold aim: 1) to ensure they wanted to remain on the waiting list and 2) to discuss consent specifically with regard to COVID-19 using an enhanced consent tool.

Results

Over a 6-week period, 79 patients were contacted. All patients were awaiting thyroid, parathyroid and adrenal operations. Of the 79 patients contacted, 77 (97%) agreed to remain on the waiting list after discussing the risks using the enhanced consent tool. The remaining 2 patients asked for their operations to be delayed. To date, none of our patients have acquired COVID-19 upon the resumption of services.

Conclusions

Despite the uncertain risks of COVID-19, the majority of patients requiring endocrine surgery were happy to proceed. Ongoing review of available literature concerning preoperative risk and COVID-19 is essential for clinicians involved in the consent process. The use of an enhanced consent tool standardised the consent process and enabled patients to make an informed decision concerning their care.

Pediatric Migraine: An Update

This article outlines key features of diagnosis and treatment of migraine in children and adolescents. It emphasizes techniques that can be used by clinicians to optimize history taking in this population, as well as recognition of episodic conditions that may be associated with migraine and present in childhood. Acute treatment strategies include use of over-the-counter analgesics and triptan medications that have been approved by the US Food and Drug Administration for use in children and adolescents. Preventive treatment approach includes lifestyle modifications, behavioral strategies, and consideration of preventive medications with the lowest side effect profiles.

High School Start Time and Migraine Frequency in High School Students

OBJECTIVE

To investigate whether later high school start time is associated with lower migraine frequency in high school students with migraine.

BACKGROUND

Adequate sleep is thought to be important in managing adolescent migraine. The American Academy of Sleep Medicine recommends teenagers sleep ≥8 hours/night. Adolescents have a physiologically delayed sleep phase, going to bed, and waking later than children and adults. The American Academy of Pediatrics (AAP) accordingly recommends high schools start no earlier than 8:30 AM.

METHODS

Cross-sectional observational study of U.S. high schoolers with migraine. Participants were recruited nationally using social media. Respondents attending high schools starting at 8:30 AM or later were compared to those attending earlier start time schools. The primary outcome was headache days/month.

RESULTS

Two hundred and fifty-six subjects constituted the analysis set: 115 later group vs 141 earlier group. Age and sex did not differ. Mean (SD) self-reported headache days/month were 7 (5) vs 8 (7), respectively, (P = .985); mean difference (95% CI for the difference) was -0.8 (-2.3-0.7) days. Median (IQR) self-reported total hours of sleep/school night were: 5.6 (5.0-6.6) vs 5.6 (4.5-6.4), P = .058. Students attending later start time schools woke later (median [IQR] 6:38 AM [55 minutes] vs 6:09 AM [59 minutes], P < .0001) and left home later (median [IQR] 7:28 AM [28 minutes] vs 7:02 AM [60 minutes], P < .0001). Average commute time was also longer: 41 (21) minutes vs 28 (16), P < .0001. The vast majority in both groups reported missing breakfast at least once/week: 103/114 (90.4%) vs 128/141 (90.8%), P = .907. Hours of sleep did not correlate with headache days per month.

CONCLUSION

High school start time does not have a large effect on headache frequency in high schoolers with migraine. Given the high variance in headache days/month observed in this study, a larger study would be needed to determine whether there might still be a small effect of starting high school at/after 8:30 AM. More research is needed to establish evidence-based recommendations about lifestyle factors in adolescent migraine management.

Mobilan: a recombinant adenovirus carrying Toll-like receptor 5 self-activating cassette for cancer immunotherapy

Toll-like receptor 5 (TLR5) is considered an attractive target for anticancer immunotherapy. TLR5 agonists, bacterial flagellin and engineered flagellin derivatives, have been shown to have potent antitumor and metastasis-suppressive effects in multiple animal models and to be safe in both animals and humans. Anticancer efficacy of TLR5 agonists stems from TLR5-dependent activation of nuclear factor-κB (NF-κB) that mediates innate and adaptive antitumor immune responses. To extend application of TLR5-targeted anticancer immunotherapy to tumors that do not naturally express TLR5, we created an adenovirus-based vector for intratumor delivery, named Mobilan that drives expression of self-activating TLR5 signaling cassette comprising of human TLR5 and a secreted derivative of Salmonella flagellin structurally analogous to a clinical stage TLR5 agonist, entolimod. Co-expression of TLR5 receptor and agonist in Mobilan-infected cells established an autocrine/paracrine TLR5 signaling loop resulting in constitutive activation of NF-κB both in vitro and in vivo. Injection of Mobilan into primary tumors of the prostate cancer-prone transgenic adenocarcinoma of the mouse prostate (TRAMP) mice resulted in a strong induction of multiple genes involved in inflammatory responses and mobilization of innate immune cells into the tumors including neutrophils and NK cells and suppressed tumor progression. Intratumoral injection of Mobilan into subcutaneously growing syngeneic prostate tumors in immunocompetent hosts improved animal survival after surgical resection of the tumors, by suppression of tumor metastasis. In addition, vaccination of mice with irradiated Mobilan-transduced prostate tumor cells protected mice against subsequent tumor challenge. These results provide proof-of-concept for Mobilan as a tool for antitumor vaccination that directs TLR5-mediated immune response toward cancer cells and does not require identification of tumor antigens.

RReACT goes global: perils and pitfalls of constructing a global open-access database of registered analgesic clinical trials and trial results

Eliminating publication bias requires ensuring public awareness of studies and access to results. Clinical trial registries provide basic trial information, but access to unbiased trial results is inadequate. Nearly all studies of trial registration and results reporting have been limited to the ClinicalTrials.gov registry. We analyzed trial registration, registry functionality, cross-registry harmonization, and results reporting on all 15 primary registries in the World Health Organization International Clinical Trials Registry Platform (ICTRP) for postherpetic neuralgia, painful diabetic neuropathy, and fibromyalgia. A total of 447 unique trials were identified, with 86 trials listed on more than one registry. A comprehensive search algorithm was used to find trial results in the peer-reviewed literature and the grey literature. Creating a global database of registered trials and trial results proved surprisingly difficult for several reasons: (1) ICTRP does not reliably identify trials listed on multiple registries, manual searches are necessary; (2) Searching ICTRP yields different results than searching individual registries; (3) Outcome measure descriptions for multiply registered trials vary between registries; (4) Registry-publication pairings are often inaccurate or incomplete; (5) Grey literature results are not permanent. Overall, only 46% of all trials had results available. Trials registered on ClinicalTrials.gov were significantly more likely to have results (52% vs. 18%, P<0.001), partly due to the ability to post results directly to the registry. In addition to the simple remedy of including trial registration numbers on all meeting abstracts and peer-reviewed papers, specific strategies are offered to facilitate identifying multiply registered studies and ensuring accurate pairing of results and publications.

Assessment of a semiautomated pelvic floor measurement model for evaluating pelvic organ prolapse on MRI

INTRODUCTION AND HYPOTHESIS

The objective of this study was to assess the performance of a semiautomated pelvic floor measurement algorithmic model on dynamic magnetic resonance imaging (MRI) images compared with manual pelvic floor measurements for pelvic organ prolapse (POP) evaluation.

METHODS

We examined 15 MRIs along the midsagittal view. Five reference points used for pelvic floor measurements were identified both manually and using our semiautomated measurement model. The two processes were compared in terms of accuracy and precision.

RESULTS

The semiautomated pelvic floor measurement model provided highly consistent and accurate locations for all reference points on MRI. Results also showed that the model can identify the reference points faster than the manual-point identification process.

CONCLUSION

The semiautomated pelvic floor measurement model can be used to facilitate and improve the process of pelvic floor measurements on MRI. This will enable high throughput analysis of MRI data to improve the correlation analysis with clinical outcomes and potentially improve POP assessment.

Natural history of herpes zoster: late follow-up of 3.9 years (n=43) and 7.7 years (n=10)

Postherpetic neuralgia (PHN) is a common complication after herpes zoster (HZ). Subjects who completed a longitudinal observational 6-month study (4 visits) of the natural history of HZ were recontacted for 2 additional follow-up visits that included pain and sensory symptom assessment, quantitative sensory testing, capsaicin response test, and 3-mm punch skin biopsies in HZ-affected, mirror-image, and control skin sites. Forty-three subjects (14 with PHN at 6 months) of the original 94 subjects in the cohort were comprehensively assessed at a median 3.9 years after HZ onset (visit 5), and 10 subjects underwent a final assessment at a median 7.7 years after HZ onset (visit 6). At 3.9 years, none of the 29 subjects who had been pain free at 6 months had a recurrence of pain. Only 2 of the 14 subjects with PHN at 6 months still had pain at 3.9 years. One subject with PHN at 6 months was free of symptoms at 3.9 years but had very mild pain at 7.7 years. Sensory function continued on a path toward normalization, but was still abnormal in many subjects, especially those who met criteria for PHN at 6 months. Even at 7.7 years, reinnervation of HZ-affected skin was not apparent.

Interactive informed consent: randomized comparison with paper consents

Informed consent is the cornerstone of human research subject protection. Many subjects sign consent documents without understanding the study purpose, procedures, risks, benefits, and their rights. Proof of comprehension is not required and rarely obtained. Understanding might improve by using an interactive system with multiple options for hearing, viewing and reading about the study and the consent form at the subject's own pace with testing and immediate feedback. This prospective randomized study compared the IRB-approved paper ICF for an actual clinical research study with an interactive presentation of the same study and its associated consent form using an iPad device in two populations: clinical research professionals, and patients drawn from a variety of outpatient practice settings. Of the 90 participants, 69 completed the online test and survey questions the day after the session (maximum 36 hours post-session). Among research professionals (n = 14), there was a trend (p = .07) in the direction of iPad subjects testing better on the online test (mean correct  =  77%) compared with paper subjects (mean correct = 57%). Among patients (n = 55), iPad subjects had significantly higher test scores than standard paper consent subjects (mean correct = 75% vs 58%, p < .001). For all subjects, the total time spent reviewing the paper consent was 13.2 minutes, significantly less than the average of 22.7 minutes total on the three components to be reviewed using the iPad (introductory video, consent form, interactive quiz). Overall satisfaction and overall enjoyment slightly favored the interactive iPad presentation. This study demonstrates that combining an introductory video, standard consent language, and an interactive quiz on a tablet-based system improves comprehension of research study procedures and risks.

Trinidadian women's knowledge, perceptions, and preferences regarding cesarean section: How do they make choices?

Objectives

The objective of this study is to determine the awareness of perception and attitude toward cesarean section (CS) in a high-user setting.

Design and methods

A cross-sectional design using multistage sampling methods was used to select participants from antenatal and postnatal clinics in a primary health care setting in north Trinidad. A multi-item structured questionnaire was designed and administered by in-depth interviews. Sociodemographic data and data about history of previous pregnancies and outcomes and about knowledge and perceptions of CSs were collected from women aged 16 years and older.

Results

Of the women who were eligible for entry into the study, 368 participated. However, participants chose not to respond to some questions. The majority of women (46.2%) were found to have very little information from which to make informed decisions about selecting CS as the preferred choice of delivery. Their preference was significantly associated with the perception of safety (maternal or fetal death, P = 0.001), difficulty (complications to mother and baby, P = 0.001), and pain (P = 0.001). Notwithstanding, persons who received information from health care professionals (odds ratio [OR], 1.9; confidence interval, 1.50–2.33) were more likely to have high or adequate levels of information about CSs. Data were analyzed using SPSS software, and ORs were calculated using logistic regression.

Conclusion

The majority of women attending antenatal and postnatal clinics in north Trinidad were not sufficiently knowledgeable about CS to enable them to make informed choices. In addition, the information obtained was from an unreliable source, emphasizing the need for information on CS to form a component of a structured antenatal education program.

Anaemia in pregnancy: associations with parity, abortions and child spacing in primary healthcare clinic attendees in Trinidad and Tobago

OBJECTIVE

To determine the prevalence of anaemia in antenatal clinic attendees; to investigate the effects of parity, age, gravidity, previous abortions, child spacing and other factors on the prevalence of anaemia in pregnancy.

METHODS

This was a retrospective and cross-sectional study. Antenatal records of 2287 pregnant women attending 40 public healthcare centres from January 2000 to December 2005 in Trinidad and Tobago were used. Data pertaining to the investigated variables were recorded. The national prevalence of anaemia was calculated and chi-square tests, odds ratios and logistic regression were used to assess the relationship between anaemia and each variable.

RESULTS

The prevalence of anaemia was 15.3% (95% CI 13.4%, 16.6%). No significant difference in the prevalence of anaemia was found among the different clinics or counties. At the first haemoglobin reading, age was inversely related to the presence of anaemia, whereas gestational age at first visit was directly related. At the final haemoglobin reading, parity, gravidity, and previous spontaneous abortions were directly related to the prevalence of anaemia, while the number of visits was inversely related. Age was inversely associated to the severity of anaemia while gravidity was directly related.

CONCLUSION

The prevalence of anaemia decreased by 18.7% from 1967. Despite this positive indication, women under 24 years and those commencing antenatal care after the first trimester are still at a higher risk for developing anaemia. Early commencement of antenatal care and close monitoring of the risk groups identified should be strongly advocated.

Lower level of endogenous dopamine in patients with cocaine dependence: findings from PET imaging of D(2)/D(3) receptors following acute dopamine depletion

OBJECTIVE

Previous positron emission tomography (PET) imaging studies have demonstrated that cocaine dependence is associated with a decrease in dopamine type 2 and 3 (D(2)/D(3)) receptor binding in cocaine-dependent individuals relative to healthy comparison subjects. However, given the nature of PET imaging, it is possible that the measured decrease in radiotracer binding results from an increase in baseline dopamine levels. The purpose of this study was to measure D(2)/D(3) receptors following acute dopamine depletion in cocaine-dependent volunteers relative to healthy comparison subjects.

METHOD

Cocaine-dependent volunteers (N=15) and healthy matched comparison subjects (N=15) were scanned using PET, with the dopamine receptor radiotracer [(11)C]raclopride, at baseline and again following acute depletion of endogenous dopamine via alpha-methyl-para-tyrosine (AMPT) administration. Changes in radiotracer binding were measured in the subdivisions of the striatum (caudate, putamen, and ventral striatum) in addition to the striatum as a whole.

RESULTS

Findings revealed that cocaine-dependent volunteers exhibited lower levels of endogenous dopamine relative to comparison subjects, which was measured as an increase in [(11)C]raclopride binding following AMPT administration. The increase in [(11)C]raclopride binding in the striatum was 11.1% (SD=4.4%) in healthy comparison subjects and 5.7% (SD=5.9%) in cocaine-dependent volunteers. Similar differences were seen in the subdivisions of the striatum.

CONCLUSIONS

The decrease in striatal D(2)/D(3 )receptors associated with cocaine dependence cannot be attributed to higher levels of endogenous dopamine.

Plasma surfactant protein levels and clinical outcomes in patients with acute lung injury

BACKGROUND

Because injury to the alveolar epithelial barrier is a characteristic feature of acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS), plasma surfactant protein levels may have prognostic value. To test this hypothesis plasma surfactant proteins A and D (SP-A and SP-D) levels were measured in patients with ALI or ARDS enrolled in the NHLBI sponsored multicentre ARDS Network randomised controlled trial of a 6 ml/kg v 12 ml/kg tidal volume strategy.

METHODS

Data from 565 participants in the clinical trial were used. Plasma levels of SP-A and SP-D were measured at baseline and on day 3 after the start of the mechanical ventilation protocol. The longitudinal impact of baseline plasma surfactant protein levels on clinical outcomes was examined by multivariate analysis, controlling for mechanical ventilation group, APACHE III score, and other clinical covariates. The effect of 6 ml/kg tidal volume ventilation on plasma SP-A and SP-D levels was evaluated using analysis of covariance.

RESULTS

Baseline plasma SP-A levels were not related to any clinical outcome. In contrast, higher baseline plasma SP-D levels were associated with a greater risk of death (OR 1.21 per 100 ng/ml increment; 95% CI 1.08 to 1.35), fewer ventilator-free days (mean decrease -0.88 days; p=0.001), and fewer organ failure-free days (mean decrease -1.06 days; p<0.0001). The 6 ml/kg tidal volume strategy had no effect on the rise in plasma SP-A levels (p=0.91) but attenuated the rise in plasma SP-D levels (p=0.0006).

CONCLUSIONS

Early in the course of ALI/ARDS an increased level of plasma SP-D is associated with a worse clinical outcome. The 6 ml/kg tidal volume strategy attenuated the rise of SP-D early in the clinical course. Taken together, these observations indicate that plasma SP-D, a product of alveolar type II cells, is a valuable biomarker in ALI/ARDS.

In vivo characterization of a porous hydrogel material for use as a tissue bulking agent

Tissue engineered biomaterial constructs are needed for plastic and reconstructive applications. To successfully form a space-filling tissue, the construct should induce a minimal inflammatory response, create minimal or no fibrotic capsule, and establish a vascular bed within the first few days after implantation to ensure survival of the implanted cells. In addition, the biomaterial should support cellular adhesion and induce tissue ingrowth. A macroporous hydrogel bead using sodium alginate covalently coupled with an arginine, glycine, and aspartic acid-containing peptide was created. A 6-month subcutaneous rat model study was performed to determine if the implanted material induced tissue ingrowth throughout the implantation area and maintained a three-dimensional vascular bed. The implanted materials produced a vascular bed, minimal inflammation and capsule formation, and good tissue ingrowth throughout the experiment. The material retained its bulking capacity by demonstration of no significant change of the cross-sectional area as measured from the center of the implants after the 2-week time point. In addition, the granulation tissue formed around the implant was loosely organized, and the surrounding tissue had integrated well with the implant. These results indicate that this material has the desired properties for the development of soft-tissue-engineering constructs.

Hexosamine-induced fibronectin protein synthesis in mesangial cells is associated with increases in cAMP responsive element binding (CREB) phosphorylation and nuclear CREB: the involvement of protein kinases A and C

Hyperglycemia-induced alterations in mesangial (MES) cell function and extracellular matrix protein accumulation are seen in diabetic glomerulopathy. Recent studies have demonstrated that some of the effects of high glucose (HG) on cellular metabolism are mediated by the hexosamine biosynthesis pathway (HBP), in which fructose-6-phosphate is converted to glucosamine 6-phosphate by the rate-liming enzyme glutamine:fructose-6-phosphate amidotransferase (GFA). In this study, we investigated the role of HBP on HG-stimulated fibronectin protein synthesis, a matrix component, in SV-40-transformed rat kidney MES cells. Treatment of MES cells with 25 mmol/l glucose (HG) for 48 h increases cellular fibronectin levels by two- to threefold on Western blots when compared with low glucose (5 mmol/l). Glucosamine (GlcN; 1.5 mmol/l), which enters the hexosamine pathway distal to GFA action, also increases fibronectin synthesis. Azaserine (AZA; 0.5 micromol/l), an inhibitor of GFA, blocks the HG- but not the GlcN-induced fibronectin synthesis. Fibronectin contains cAMP responsive element (CRE) consensus sequences in its promoter and the phosphorylation of CRE-binding protein (CREB) may regulate its expression. On Western blots, HG and GlcN stimulate two- to threefold the phosphorylation of CREB at Ser 133, whereas CREB protein content was unaltered by either HG or GlcN. In addition, nuclear CREB activity was increased by HG and GlcN on gel-shift assays using (32)P-CRE oligonucleotides. AZA impeded the HG-enhanced CREB phosphorylation and CRE binding but had no effect on GlcN-mediated CREB phosphorylation and CRE binding. Pharmacologic inhibition of protein kinase C (PKC) and protein kinase A (PKA), which are involved in hexosamine-mediated matrix production, blocked the CREB phosphorylation and fibronectin synthesis seen in HG and GlcN conditions. We conclude that the effects of HG on fibronectin synthesis in the mesangium are mediated by the HBP possibly via hexosamine regulation of CREB and PKC/PKA signaling pathways. These results support the hypothesis that the HBP is a sensor and regulator of the actions of glucose in the kidney.

Carotid endarterectomy based on duplex ultrasound in patients with and without hemispheric symptoms

Carotid endarterectomy is the most commonly performed vascular procedure. This retrospective study was conducted to determine the efficacy of duplex imaging as the sole diagnostic study for preoperative evaluation of symptomatic and asymptomatic patients who underwent carotid endarterectomy. We conducted a retrospective case series analysis in a community teaching hospital. From January 1994 to September 1998, 316 patients underwent carotid endarterectomy for carotid stenosis. A total of 177 patients were symptomatic and 139 patients were asymptomatic. Angiography was performed routinely in the beginning of the study but later was performed only in selected patients. Preoperative duplex ultrasound of carotid artery was performed by a laboratory accredited by the Intersocietal Commission for the Accreditation of Vascular Laboratories. Data were reviewed to obtain morbidity and mortality rates, and duplex imaging results were compared with operative findings. Cost and risk analysis of carotid angiography reviewed. This study reviewed variables of age, sex, race, diabetes, smoking, hypertension, hypercholesterolemia, coronary artery disease, and renal failure. Five patients had a lesion in the proximal portion of the carotid artery by duplex imaging criteria. Duplex ultrasound results were grossly confirmed intraoperatively in all patients except in one patient who was found to have complete occlusion of carotid artery whose duplex was read as high-grade stenosis. The duration of stay ranged from two to 30 days. This duration was influenced by patients' comorbid conditions, postoperative complications or simultaneous coronary artery bypass graft. Four patients had a stroke within 30 days of surgery making the stroke rate of 1.26 per cent. There has been considerable debate on the use of duplex ultrasound as the only method of preoperative evaluation of carotid stenosis before carotid endarterectomy. Our study demonstrates that it is safe to perform carotid endarterectomy based on neurologic history and duplex ultrasound with good technical quality performed in an accredited vascular laboratory. This approach eliminates the cost and risk associated with angiography. Proximal carotid and intrathoracic lesions are rare and can be predicted by the duplex study. We think that carotid angiography is required only when duplex imaging is suboptimal or equivocal in the presence of atypical symptoms or uncommon vascular abnormalities.

Carotid Endarterectomy Based on Duplex Ultrasound in Patients with and without Hemispheric Symptoms

Carotid endarterectomy is the most commonly performed vascular procedure. This retrospective study was conducted to determine the efficacy of duplex imaging as the sole diagnostic study for preoperative evaluation of symptomatic and asymptomatic patients who underwent carotid endarterectomy. We conducted a retrospective case series analysis in a community teaching hospital. From January 1994 to September 1998, 316 patients underwent carotid endarterectomy for carotid stenosis. A total of 177 patients were symptomatic and 139 patients were asymptomatic. Angiography was performed routinely in the beginning of the study but later was performed only in selected patients. Preoperative duplex ultrasound of carotid artery was performed by a laboratory accredited by the Intersocietal Commission for the Accreditation of Vascular Laboratories. Data were reviewed to obtain morbidity and mortality rates, and duplex imaging results were compared with operative findings. Cost and risk analysis of carotid angiography reviewed. This study reviewed variables of age, sex, race, diabetes, smoking, hypertension, hypercholesterolemia, coronary artery disease, and renal failure. Five patients had a lesion in the proximal portion of the carotid artery by duplex imaging criteria. Duplex ultrasound results were grossly confirmed intraoperatively in all patients except in one patient who was found to have complete occlusion of carotid artery whose duplex was read as high-grade stenosis. The duration of stay ranged from two to 30 days. This duration was influenced by patients’ comorbid conditions, postoperative complications or simultaneous coronary artery bypass graft. Four patients had a stroke within 30 days of surgery making the stroke rate of 1.26 per cent. There has been considerable debate on the use of duplex ultrasound as the only method of preoperative evaluation of carotid stenosis before carotid endarterectomy. Our study demonstrates that it is safe to perform carotid endarterectomy based on neurologic history and duplex ultrasound with good technical quality performed in an accredited vascular laboratory. This approach eliminates the cost and risk associated with angiography. Proximal carotid and intrathoracic lesions are rare and can be predicted by the duplex study. We think that carotid angiography is required only when duplex imaging is suboptimal or equivocal in the presence of atypical symptoms or uncommon vascular abnormalities.

The development and evaluation of a computer-assisted teaching programme for intrapartum fetal monitoring

OBJECTIVE

The development and evaluation of a computer-assisted teaching programme of cardiotocography and acid-base balance.

DESIGN

Randomised controlled trial.

PARTICIPANTS

One hundred and seventeen midwifery and obstetric staff at Derriford Hospital, Plymouth.

METHODS

The obstetricians and midwives were randomly allocated to use the teaching programme, either early or late. The late group (control) used the teaching programme three months after the early group. To assess the effect of the teaching programme, participants were tested on four occasions over eight months by a multiple choice questionnaire. Two questionnaires on ease of use were also completed.

MAIN OUTCOME MEASURES

Multiple choice questionnaire scores and opinion questionnaire results.

RESULTS

The mean score in the early group improved from 50-8% (test 1, pre-teaching programme) to 70.2% (test 2, post-teaching programme). The mean score in the control group was 50.3% (test 1) and 54.8% (test 2). Knowledge was retained up to seven months.

CONCLUSIONS

The teaching programme was effective in improving knowledge of acid-base balance and cardiotocography and can be used by all staff whilst on duty on the labour ward.

Targeting adolescent risk-taking behaviors: the contributions of egocentrism and sensation-seeking

Tremendous resources are spent each year developing programs and messages targeting adolescent risk behavior. Adolescents are often reasonably well educated about methods for health promotion such as preventing HIV infection, yet they fail to act accordingly. One widely used individual difference variable, sensation-seeking, has been incorporated in health message design to some extent, but it fails to take development into account. Research on adolescent egocentrism suggests adolescents experience personal fable which can lead to an exaggerated sense of invulnerability. The present study sampled adolescents and college students to examine relative contributions of egocentrism and sensation-seeking to risk-taking behavior. Results indicate a latent factor labeled risk-seeking (primarily indicated by disinhibition and risk-taking personality, and to a lesser degree by invulnerability, experience-seeking, boredom susceptibility, and thrill and adventure-seeking) indeed predicted a latent factor labeled delinquent behavior (primarily indicated by alcohol consumption and delinquency, and to a lesser degree by drug use, drinking and driving, and risky driving). Other results indicate consistently high personal fable combined with high sensation-seeking explained most risk-taking behavior. Implications and directions for future research are discussed.

Botanical medicines with gynecological anticancer activity: a literature review

This article reviews the existing scientific literature reporting effects of botanical substances on the prevention and treatment of gynecological cancers. Anticancer effects were reported for 14 of 27 herbal substances searched for, 8 of which had reported effects specifically in gynecological cancer models. Research reviewed included in vitro studies in gynecological cancer cell lines, animal studies, an ex vivo study, and an epidemiological study. No clinical trials on gynecological cancer prevention or treatment were found for any of the 8 identified agents. Despite the increasing use of botanical medicines in the prevention and treatment of cancer in general, there is a paucity of studies describing their efficacy or safety in gynecological cancer. Given the prevalent use of botanical medicine in complementary and alternative cancer therapy, the need for research to evaluate safety and efficacy using both in vitro and in vivo methods is pressing.

Bilateral thalamic infarction in a patient with factor V Leiden mutation

In a 50-year-old unresponsive man with ophthalmoplegia, bilateral thalamic infarction was detected on magnetic resonance imaging of the brain. A thorough evaluation, including urinalysis, laboratory studies, computed tomography of the brain, chest radiography, lumbar puncture, magnetic resonance angiography, cerebral angiography, carotid ultrasonography, and transesophageal echocardiography, revealed no obvious predisposing factors other than heterozygous factor V Leiden mutation. To our knowledge, this is the first reported case of bilateral thalamic infarction associated with factor V Leiden mutation. Physicians should consider the possibility of this mutation in patients with ischemic stroke if no other source is evident.

Diarrhoea prevention in Bolivia through point-of-use water treatment and safe storage: a promising new strategy

A novel water quality intervention that consists of point-of-use water disinfection, safe storage and community education was field tested in Bolivia. A total of 127 households in two periurban communities were randomized into intervention and control groups, surveyed and the intervention was distributed. Monthly water quality testing and weekly diarrhoea surveillance were conducted. Over a 5-month period, intervention households had 44% fewer diarrhoea episodes than control households (P = 0.002). Infants < 1 year old (P = 0.05) and children 5-14 years old (P = 0.01) in intervention households had significantly less diarrhoea than control children. Campylobacter was less commonly isolated from intervention than control patients (P = 0.02). Stored water in intervention households was less contaminated with Escherichia coli than stored water in control households (P < 0.0001). Intervention households exhibited less E. coli contamination of stored water and less diarrhoea than control households. This promising new strategy may have broad applicability for waterborne disease prevention.

Surfactant protein A and surfactant protein D in health and disease

Surfactant protein (SP) A and SP-D are collagenous glycoproteins with multiple functions in the lung. Both of these proteins are calcium-dependent lectins and are structurally similar to mannose-binding protein and bovine conglutinin. Both form polyvalent multimeric structures for interactions with pathogens, cells, or other molecules. SP-A is an integral part of the surfactant system, binds phospholipids avidly, and is found in lamellar bodies and tubular myelin. Initially, most research interest focused on its role in surfactant homeostasis. Recently, more attention has been placed on the role of SP-A as a host defense molecule and its interactions with pathogens and phagocytic cells. SP-D is much less involved with the surfactant system. SP-D appears to be primarily a host defense molecule that binds surfactant phospholipids poorly and is not found in lamellar inclusion bodies or tubular myelin. Both SP-A and SP-D bind a wide spectrum of pathogens including viruses, bacteria, fungi, and pneumocystis. In addition, both molecules have been measured in the systemic circulation by immunologic methods and may be useful biomarkers of disease. The current challenges are characterization of the three-dimensional crystal structure of SP-A and SP-D, molecular cloning of their receptors, and determination of their precise physiological functions in vivo.

Efficacy of surgical wound drainage in orthopaedic trauma patients: a randomized prospective trial

OBJECTIVE

To study the efficacy of closed suction drainage in clean nonemergent surgical fracture fixation or bone grafting on the extremities or pelvis.

DESIGN

A prospective randomized trial.

SETTING

The orthopaedic trauma service of a Level I trauma hospital.

PATIENTS

Patients were older than age eighteen years and undergoing clean nonemergent surgical fracture fixation or bone grafting procedures on the extremities (excluding hands and feet) or pelvis.

INTERVENTION

The application of a surgical drain.

MAIN OUTCOME MEASUREMENTS

Wound drainage, edema, hematoma and erythema, dehiscence, infection, and need for surgery or readmission were followed for six weeks. A univariate analysis with Student's t test for continuous variables and chi-squared analysis for all categorical data were used, with a p value of < or = 0.05 considered statistically significant.

RESULTS

A total of 202 patients were randomized to 102 patients with no drain and 100 patients with a drain. There was no significant difference between the groups with regard to injury severity, systemic disease, age, body weight, physical status, or estimated blood loss. There was no significant difference between the drain and no-drain groups in any of the parameters evaluated.

CONCLUSION

There is no significant difference between drained and nondrained wounds in clean, nonurgent orthopaedic trauma surgery. It appears that drainage systems can be safely eliminated in this group.

Monitoring soluble interleukin-2 receptor levels in related and unrelated donor allogenic bone marrow transplantation

Acute graft-versus-host disease (GVHD) is effected by donor T lymphocytes which have been stimulated by host antigens. Activated donor T lymphocytes express interleukin-2 receptor (IL-2R), which is comprised of three subunits (alpha, beta, gamma). During activation, the a IL-2R subunit (CD25) is shed from the receptor complex and can be measured in the circulation. Soluble IL-2Ralpha (sIL-2R) levels are increased in states of immune activation including GVHD, and could theoretically be used as a guide to therapy. Since IL-2Ralpha expression is an early marker of T cell activation, we investigated: (1) if an increase in sIL-2R is specific for acute GVHD; and (2) if serial sIL-2R levels can identify patients with early GVHD, prior to the onset of clinical tissue damage (effector function). Weekly sIL-2R levels were monitored in 36 patients undergoing matched related (n=23) or matched unrelated (n=13) allogeneic bone marrow transplantation (BMT). There was no significant difference in sIL-2R levels between matched related and matched unrelated recipients. Patients with acute GVHD (n=19, 53%) demonstrated higher sIL-2R levels, than those without during weeks 2 and 3 post-BMT (P=0.02 and 0.04, Mann-Whitney U test, two-tailed). In patients with acute GVHD, the rise in sIL-2R preceded the clinical signs of GVHD (16/19 patients). However, patients with sepsis demonstrated a trend towards higher sIL-2R levels at week 1 and significantly greater levels by week 4 (P=0.02). Furthermore, patients with veno-occlusive disease (VOD) (25%) also had significantly higher sIL-2R levels at week 2 (P=0.03). We conclude that although sIL-2R levels increase in patients with acute GVHD, similar increases are seen in patients with VOD and/or sepsis and therefore, as a single biochemical marker, we find that serial measurements of sIL-2R lacks sufficient specificity to guide GVHD therapy.

Removal of Mycobacterium species by breathing circuit filters

Breathing circuit filters (BCFs) are used in respiratory and critical-care settings for humidification of air and to limit transmission of respiratory pathogens. Three types of BCFs (Pall BB 25A, BB 100, and HME 15-22) were evaluated (in triplicate) for removal of Mycobacterium species. Filters were challenged with aerosolized Mycobacterium bovis (a surrogate for Mycobacterium tuberculosis), at minimum total concentrations of 10(4) colony-forming units. No M bovis was recovered in the effluent, providing removal efficiencies of > 99.99% to > 99.999% for the filters tested.

Different binding mode in AT and GC sequences for unfused-aromatic dications

We have previously synthesized a 2,5-diphenylfuranamidine dication (4) and presented evidence that this compound binds to AT sequences in DNA by a minor-groove interaction mode but binds to GC sequences by intercalation (1,2). To probe these sequence-dependent binding modes in more detail, and particularly to obtain additional evidence for the binding mode in GC rich sequences, we have synthesized and studied the DNA complexes of 1-3 which have the furan ring of 4 replaced by 2,6-substituted pyridine (1), pyrimidine (2), or triazine (3) ring systems. The three compounds with a six-membered central ring system bind to AT DNA sequences more weakly than the furan compound, but retain the minor-groove binding mode. The pyridine and pyrimidine derivatives bind to GC sequences of DNA more strongly than the furan, but the triazine derivative binds more weakly. The aromatic proton signals of 1-3, as previously observed with 4 shift upfield by approximately 0.5 ppm or greater on complex formation with polyd(G-C)2. This and other spectroscopic as well as viscosity and kinetics results indicate that 1-4 bind to GC sites in DNA by intercalation. A nonclassical intercalation model, with the twisted-unfused, aromatic ring system intercalated into an intercalation site of matching structure can explain all of our and the literature results for the GC binding mode of these unfused, aromatic compounds.

Multinuclear nuclear magnetic resonance studies of Na cation-stabilized complex formed by d(G-G-T-T-T-T-C-G-G) in solution. Implications for G-tetrad structures

There has been much recent interest in the self-association of short deoxyguanosine-rich motifs within single-stranded DNAs to generate monovalent cation modulated four-stranded helical segments called G-quadruplexes stabilized by hydrogen-bonded G-tetrad alignments. We have addressed structural aspects of this novel alignment and report on multinuclear 1H, 31P and 13C nuclear magnetic resonance studies on the d(G2T4CG2) deoxynonanucleotide with Na cation as counterion in aqueous solution at low temperature. This sequence forms stable structures even though it cannot align by Watson-Crick hydrogen bond formation (see the paper on d(G2T5G2) describing optical and calorimetric measurements by Jin, R., Breslauer, K. J., Jones, R. A. & Gaffney, B. L. (1990), Science, 250, 543-546). The four narrow exchangeable protons detected between 11.5 and 12.0 parts per million (p.p.m.), which are common to the d(G2T4CG2) deoxynonanucleotide and the d(G2TCG2) deoxyhexanucleotide sequences, are assigned to deoxyguanosine imino protons hydrogen-bonded to carbonyl acceptor groups. These narrow imino protons are not detected for d(IGN5IG) and d(I2N5G2), where two deoxyguanosine residues are replaced by two deoxyinosine residues in the deoxynonanucleotide sequences. This implies that the 2-amino protons of deoxyguanosine must also participate in hydrogen bond formation and stabilize the structured conformation of d(G2T4CG2) in Na cation-containing solution. We have completely assigned the base and sugar H1', H2',2'', H3', and H4' protons of the d(G2T4CG2) oligomer following analysis of two-dimensional nuclear Overhauser enhancement spectroscopy and two-dimensional correlated spectroscopy data sets in 0.1 M-NaCl, 10 mM-sodium phosphate, 2H2O solution at 0 degree C. The relative magnitude of the nuclear Overhauser enhancements (NOEs) between the base H8 and its own sugar H1' protons of individual deoxyguanosine residues establishes that G1 and G8 adopt syn orientations while G2 and G9 adopt anti orientations about the glycosidic bond in the d(G1-G2-T3-T4-T5-T6-C7-G8-G9) sequence in both Na and K cation-containing aqueous solution. Consequently, any structure proposed for the tetramolecular complex of d(G2T4CG2) must exhibit alternating G(syn) and G(anti) glycosidic torsion angles within each strand. The directionality and magnitude of the observed NOEs are consistent with the G(syn)-G(anti) steps adopting right-handed helical conformations in solution. We also note that the H8 protons of G1 and G8 (7.35 to 7.45 p.p.m.) in a syn alignment are shifted significantly upfield from the H8 protons of G2 and G9 (8.0 to 8.3 p.p.m.) in an anti alignment.(ABSTRACT TRUNCATED AT 400 WORDS)

Molecular epidemiologic techniques in analysis of epidemic and endemic Shigella dysenteriae type 1 strains

During 1988 the number of Shigella dysenteriae type 1 infections reported in the United States increased fivefold. To determine if recent isolates from Mexico were related to those that caused epidemics of dysentery worldwide, Southern hybridization analysis was done with Shiga toxin and ribosomal RNA gene probes. Western hemisphere and Eastern Hemisphere strains differed by the size of a single EcoRI fragment carrying the Shiga toxin genes. Three ribosomal DNA (rDNA) patterns were observed, which correlated with the strain's continental origin for 81 of 83 isolates tested. Together the Shiga toxin and rDNA probe results indicated that recent Mexican isolates were chromosomally similar to earlier Central American isolates and distinct from Asian and African strains. This suggests there has been no significant exchange of organisms between continents in recent decades and that the 1988 outbreak in Mexico was caused by strains present in Central America since at least 1962.

Development and evaluation of enzyme-linked immunosorbent assays for detection of shiga-like toxin I and shiga-like toxin II

Shiga-like toxin (SLT)-producing Escherichia coli has been associated with a spectrum of human illnesses, including hemorrhagic colitis and hemolytic uremic syndrome. It produces at least two antigenically distinct toxins designated SLT-I and SLT-II, which have been implicated in disease. Currently available toxin assays, however, are not suitable for most clinical or public health laboratories. In this study, we have developed two sandwich enzyme-linked immunosorbent assays (ELISAs) based on toxin-specific murine monoclonal capture antibodies and rabbit polyclonal second antibodies which are specific for SLT-I and SLT-II. The SLT-I ELISA detected 200 pg of purified SLT-I, and the SLT-II ELISA detected 75 pg of purified SLT-II. The types of SLT produced by 166 human and 54 animal isolates of E. coli that produced moderate to high levels of toxin were determined by the ELISA, and results were confirmed by cytotoxin neutralization assays. With the exception of results from three strains, the tests agreed on the types of toxin present. DNA probe assays of 86 of 87 isolates also agreed with the ELISA and neutralization results. Although the SLT-II ELISA was specific for the SLT-II variant produced by porcine edema strains, most of the isolates examined produced levels of toxin (less than 50 50% cytotoxic doses [CD50] per ml) below the detection limit of the test. The ELISAs were not sufficiently sensitive to consistently detect low levels of toxin (less than 50 CD50 per ml) found in fecal extracts. On the basis of these findings, both ELISAs appeared to detect significant levels of SLT-I ( > 100 CD50 per ml) and SLT-II ( > 50 CD50 per ml) in E. coli culture extracts and should be useful diagnostic tools in many microbiology laboratories.

Chemosensitization of L-phenylalanine mustard by the thiol-modulating agent buthionine sulfoximine

Glutathione (GSH) plays a crucial role in the protection of normal and tumor tissue against the toxic effects of numerous chemotherapeutic drugs. Therefore, the possible therapeutic benefit of thiol depletion in cancer treatment is dependent upon the relative degree to which tumor or normal tissue is sensitized to the toxic effects of subsequent chemotherapy. To address this issue, the following studies on the chemosensitization of melphalan (L-PAM) by the thiol-depleting agent buthionine sulfoximine (BSO) were conducted in vivo in BDF mice inoculated with L-PAM-resistant murine L1210 leukemia. Different dosing regimens of BSO were found to potentiate L-PAM toxicity in a manner that depended upon the degree of GSH depletion. Multiple i.p. injections of BSO (450 mg/kg every 6 h X 5) were found to reduce GSH concentrations in most tissues by 70-80%, and to decrease the LD50 for L-PAM from 22 to 14 mg/kg. No two organs were found to behave entirely the same with respect to the rate of depletion or recovery of GSH, or to the maximum depletion that could be obtained by BSO. In this regard, the bone marrow was found to be the most resistant tissue to thiol depletion by BSO and was found to tolerate the combination of BSO and therapeutic doses of L-PAM. However, BSO pretreatment markedly inhibited the recovery of the peripheral WBC population at the LD10 dose of L-PAM. Differences also were found in the in vivo metabolism of GSH by L-PAM-sensitive and -resistant murine L1210 leukemia cells. The intracellular concentration of GSH in the resistant cell line was 1.6-fold higher than in the sensitive tumor. Moreover, GSH levels were depleted more rapidly in the resistant tumor relative to the sensitive cell line. A single injection of BSO decreased GSH concentrations in both tumors to equivalent levels (20 nmol/10(7) cells) within 24 h. However, multiple i.p. injections of BSO failed to produce a significant increase in the life-span of L-PAM-treated animals despite a 90% reduction in tumor GSH concentrations (5.5 nmol/10(7) cells). In contrast to the median day survival data, BSO was found to enhance the antitumor activity of L-PAM as determined by an in vivo/in vitro clonogenic assay or by in vivo thymidine incorporation. Using decreased thymidine incorporation as an index of antitumor activity, BSO was found to increase the therapeutic index (LD10/ED50) of L-PAM from 3.6 to 6.5.(ABSTRACT TRUNCATED AT 400 WORDS)