A plastic scintillator and HPGe β-γ coincidence detection system

A network of specialist laboratories support the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) with re-measurements of radionuclide samples, including xenon gas. The measurement of four xenon fission product radionuclides (133Xe, 135Xe, 131mXe and 133mXe) can be used to detect an underground nuclear explosion. Laboratories use a range of techniques to measure the radionuclides, including beta-gamma (β-γ) coincidence spectrometry. These highly-sensitive measurements are capable of detecting concentrations of down to 500 atoms of 133Xe in a few cm3 of xenon. In some detector systems, detection of the metastable isomers (131mXe and 133mXe) can be more challenging due to interferences between the signatures of different radionuclides. Recent work has shown that using high-purity Germanium (HPGe) high-resolution gamma detectors, these interferences can be reduced, lowering the dependence of the detection limits on radionuclide sample isotopic composition. One downside of these detectors is the reduction in detection efficiency, which impacts the overall detection sensitivity; so assessing different detector systems is a priority for radionuclide laboratories. This work presents a coincidence detector system comprising of a plastic scintillator gas cell and a large-crystal high-purity germanium detector. The energy resolution, coincidence detection efficiency, MDA and interference factors are determined from measurements of synthetic radioxenon gas samples.

Definitions of Remission in Psoriasis: A Systematic Literature Review from the National Psoriasis Foundation

Psoriasis studies increasingly employ outcomes that indicate complete disease resolution, yet remission and cure are poorly defined for psoriasis. We conducted a systematic literature review to identify definitions of psoriasis remission and cure reported in the literature. Medline, EMBASE, and The Cochrane Central Register of Controlled Trials databases were searched on July 22, 2020 for full-text studies providing definitions for psoriasis remission/cure. Definitions were analyzed descriptively for endpoint, time-frame, on/off treatment, patient-reported outcomes, and disease domains. We identified 106 studies that provided 41 unique remission definitions. Most definitions included endpoints based on Psoriasis Area and Severity Index (PASI), such as PASI75 (n=16 studies), PASI90 (n=10), PASI100 (n=10), and PASI of 0 (n=3), and descriptive endpoints related to 'skin clearance' (n=18). Few definitions specified time-frame, on/off treatment or other psoriasis-related disease domains. One small consensus-initiative defined drug-free remission for plaque psoriasis by BSA of 0 without any therapy for at least 12 months. While there is no cure for psoriasis, seven studies defined psoriasis cure using similar endpoints to those used to define remission. We identified a variety of definitions of psoriasis remission. These results will inform the development of consensus-based definitions for psoriasis remission to support efforts to improve research and clinical outcomes.

Efficacy of thiopurines and adalimumab in preventing Crohn's disease recurrence in high-risk patients - a POCER study analysis

BACKGROUND

Crohn's disease recurs in the majority of patients after intestinal resection.

AIM

To compare the relative efficacy of thiopurines and anti-TNF therapy in patients at high risk of disease recurrence.

METHODS

As part of a larger study comparing post-operative management strategies, patients at high risk of recurrence (smoker, perforating disease, ≥2nd operation) were treated after resection of all macroscopic disease with 3 months metronidazole together with either azathioprine 2 mg/kg/day or mercaptopurine 1.5 mg/kg/day. Thiopurine-intolerant patients received adalimumab induction then 40 mg fortnightly. Patients underwent colonoscopy at 6 months with endoscopic recurrence assessed blind to treatment.

RESULTS

A total of 101 patients [50% male; median (IQR) age 36 (25-46) years] were included. There were no differences in disease history between thiopurine- and adalimumab-treated patients. Fifteen patients withdrew prior to 6 months, five due to symptom recurrence (of whom four were colonoscoped). Endoscopic recurrence (Rutgeerts score i2-i4) occurred in 33 of 73 (45%) thiopurine vs. 6 of 28 (21%) adalimumab-treated patients [intention-to-treat (ITT); P = 0.028] or 24 of 62 (39%) vs. 3 of 24 (13%) respectively [per-protocol analysis (PPA); P = 0.020]. Complete mucosal endoscopic normality (Rutgeerts i0) occurred in 17/73 (23%) vs. 15/28 (54%) (ITT; P = 0.003) and in 27% vs. 63% (PPA; P = 0.002). The most advanced disease (Rutgeerts i3 and i4) occurred in 8% vs. 4% (thiopurine vs. adalimumab).

CONCLUSIONS

In Crohn's disease patients at high risk of post-operative recurrence adalimumab is superior to thiopurines in preventing early disease recurrence.

The relationships between IFNL4 genotype, intrahepatic interferon-stimulated gene expression and interferon treatment response differs in HCV-1 compared with HCV-3

BACKGROUND

The biological mechanism underlying the association between IFNL4/IFNL3 polymorphism and peginterferon/ribavirin (PR) response in HCV-1 is thought to involve differential intrahepatic interferon-stimulated gene expression. HCV-3 is more sensitive to PR, but there are no studies of the association between IFNL4 polymorphism, PR treatment response and liver interferon-stimulated gene expression in HCV-3.

AIM

We evaluated the association between IFNL4/IFNL3 genotypes, PR treatment outcomes and intrahepatic interferon-stimulated gene expression, according to HCV genotype.

METHODS

HCV-1 and HCV-3 patients who received PR therapy were identified. IFNL3 (rs12979860) and IFNL4 genotype (rs368234815) were determined. A second cohort with stored liver specimens was identified. Expression of ISGs was measured by rt-PCR.

RESULTS

Two hundred and fifty-nine patients were identified: 55% HCV-1, 45% HCV-3. IFNL4 genotype frequency was TT/TT 44%, TT/ΔG 42% andΔG/ΔG 14%. Linkage disequilibrium with IFNL3 genotype was high (r(2) = 0.98). The association between IFNL4 genotype and PR response was attenuated in HCV-3 vs. HCV-1 (HCV-3: SVR 89% vs. 76% vs. 72% for TT/TT vs. TT/ΔG vs. ΔG/ΔG, P = 0.09; HCV-1: SVR: 82% vs. 29% vs. 24%, P < 0.001). Intrahepatic ISG expression was evaluated in 92 patients; 61% HCV-1. The association between IFNL4 genotype and liver ISG expression was significantly different for HCV-3 vs. HCV-1 (P-value for interaction = 0.046), with levels of interferon-stimulated gene expression being highest in HCV-1 patients who carried a poor-response IFNL4 genotype.

CONCLUSIONS

The relationship between IFNL4 genotype and PR treatment response as well as intrahepatic interferon-stimulated gene expression differs between HCV-1 and HCV-3. These data suggest fundamental differences in host-virus interactions according to HCV genotype.

Perspectives of paediatric and adult gastroenterologists on transfer and transition care of adolescents with inflammatory bowel disease

BACKGROUND

Programmes specific to inflammatory bowel disease (IBD) that facilitate transition from paediatric to adult care are currently lacking.

AIM

We aimed to explore the perceived needs of adolescents with IBD among paediatric and adult gastroenterologists and to identify barriers to effective transition.

METHODS

A web-based survey of paediatric and adult gastroenterologists in Australia and New Zealand employed both ranked items (Likert scale; from 1 not important to 5 very important) and forced choice items regarding the importance of various factors in facilitating effective transition of adolescents from paediatric to adult care.

RESULTS

Response rate among 178 clinicians was 41%. Only 23% of respondents felt that adolescents with IBD were adequately prepared for transition to adult care. Psychological maturity (Mean = 4.3, standard deviation (SD) = 0.70) and readiness as assessed by adult caregiver (Mean = 4, SD = 0.72) were prioritised as the most important factors in determining timing of transfer. Self-efficacy and readiness as assessed by adult caregiver were considered the two most important factors to determine timing of transition by both groups of gastroenterologists. Poor medical and surgical handover (Mean = 4.10, SD = 0.8) and patients' lack of responsibility for their own care (Mean= 4.10, SD = 0.82) were perceived as major barriers to successful transition by both paediatric and adult gastroenterologists.

CONCLUSIONS

Deficiencies exist in current transition care of adolescents with IBD in Australia and New Zealand. Standardising transition care practices with strategies aimed at optimising communication, patient education, self-efficacy and adherence may improve outcomes.

Development and validation of a patient-reported disability measurement tool for patients with inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease can impact on a patient's ability to maintain normal physical and mental function, and fulfil their social, family and work roles. Aspects of disability in IBD have received little attention.

AIM

To develop, validate and apply a questionnaire directed towards evaluating these disease aspects.

METHODS

A literature review on disability in IBD was undertaken, and opinion about aspects of disability to measure was sought from six IBD-specialised gastroenterologists. A questionnaire was developed, and IBD patients completed the new disability questionnaire, the SF-36 and the short-IBD (SIBDQ - 10 point). A subgroup of patients completed the questionnaire again 4 weeks later. Healthy volunteers were studied as a control group.

RESULTS

A total of 116 IBD out-patients were approached, of whom 81 (52 Crohn's disease and 28 ulcerative colitis) participated. Nineteen patients were re-evaluated at 4 weeks. Twenty-five controls were studied. All subscales demonstrated good Cronbach's alpha reliability and reproducibility. There was a significant inverse correlation between the disability score and the SIBDQ and between the disability score and the SF36 and a positive correlation with the Crohn's Disease Activity Index (CDAI) (all P < 0.001). Disability differed between ulcerative colitis and controls, but not between active and inactive disease.

CONCLUSIONS

The new disability questionnaire is sensitive for detecting disability, is reliable and reproducible, and correlates with disease activity in Crohn's disease, but not ulcerative colitis. Further prospective testing is now needed in the longer term, larger patient populations and in different countries and ethnicities.

Postoperative recurrence of Crohn's disease: impact of endoscopic monitoring and treatment step-up

AIM

Eighty per cent of patients with Crohn's disease require surgery, of whom 70% will require a further operation. Recurrence occurs at the anastomosis. Although often recommended, the impact of postoperative colonoscopy and treatment adjustment is unknown.

METHOD

Patients with a bowel resection over a 10-year period were reviewed and comparison made between those who did and did not have a postoperative colonoscopy within 1 year of surgery, and those who did or did not have a step-up in drug therapy.

RESULTS

Of 222 patients operated on, 136 (65 men, mean age 33 years, mean disease duration 8 years, median follow-up 4 years) were studied. Of 70 patients with and 66 without postoperative colonoscopy, clinical recurrence occurred in 49% and 48% (NS) and further surgery in 9% and 5% (NS). Eighty-nine per cent of colonoscoped patients had a decision based on the colonoscopic findings: of these, 24% had a step-up of drug therapy [antibiotics (n =10), aminosalicylates (n=2), thiopurine (n=5), methotrexate (n=1)] and 76% had no step-up in drug therapy. In colonoscoped patients clinical recurrence occurred in 9 (60%) of 15 patients with, and 23 (49%) of 47 without step-up and surgical recurrence in 2 (13%) of 15 and 4 (9%) of 47 (NS).

CONCLUSION

Clinical recurrence occurs in a majority of patients soon after surgery. In this cohort, there was no clinical benefit from colonoscopy or increased drug therapy within 1 year after operation. However, the response to the endoscopic findings was not standardized and immunosuppressive therapy was uncommon. Standardizing timing of colonoscopy and drug therapy, including more intense therapy, may improve outcome, although this remains to be proven.

Gastroenterology training in Australia: a perspective from the coal face

BACKGROUND

The Royal Australasian College of Physicians is developing curricula for training.

AIMS

We surveyed gastroenterology trainees on their training experience to establish whether training needs were being met.

METHODS

An online anonymous survey of all gastroenterology trainees in 2009.

RESULTS

Ninety-one per cent of trainees responded (105/115). Of these, 92% were adult, and 8% were paediatric trainees. Seventy four were core, and 31 were noncore trainees. Of those who had completed core training, the majority (86%) felt that their training had prepared them adequately for independent practice as a gastroenterologist. However, most respondents felt that core advanced training should be 3 years instead of 2 years. The majority (86%) saw a benefit in moving between hospitals during core training. Of the trainees managing inpatients, 57% were managing 10 or more per day, and 63% had three or more consultant ward rounds per week. The top three noncore fellowships were advanced endoscopy (44%), hepatology (28%) and inflammatory bowel disease (17%). Sixty-one per cent and 39% were undertaking a clinical and research fellowship respectively. Seventy-two per cent of core trainees attended up to three endoscopy lists per week, and 76% were on the on-call urgent endoscopy roster. For on-call endoscopy, 27% of third-year noncore trainees and 5% of core trainees were unsupervised.

CONCLUSIONS

The majority of trainees felt that their core training would prepare them adequately for independent practice as gastroenterologists. Overall, trainees valued movement between hospitals during training and felt that core training should be 3 years. Some trainees had inadequate consultant support for out-of-hours emergency endoscopy.

Gastroenterology training in Australia: how much is enough?

BACKGROUND

Advanced training in gastroenterology currently consists of 2 years of core training and 1 elective (non-core) year. We surveyed gastroenterologists 2-7 years following completion of training to determine the strengths and weaknesses of their training.

METHODS

All gastroenterologists were invited to participate in an anonymous online survey.

RESULTS

There was a 46% response rate (49/110). Eighty-one per cent were male with most aged 36-45. Respondents felt that the current training programme prepared them well for public practice and endoscopy but less well for private practice, ambulatory care, surgical aspects of gastroenterology and functional gastrointestinal disorders. Most had faced challenges transitioning to consultant practice. The majority (53%) spent more than the standard 3 years to complete training in gastroenterology. The top three subspecialty Fellowships were in endoscopy (45%), inflammatory bowel disease (29%) and hepatology (23%). In their elective year, 42% undertook a predominantly clinical year (registrar-type position in general or subspecialty gastroenterology), 28% engaged in research while 24% trained in another specialty. Seventy-eight per cent were in full-time work, and 36% were supervising trainees. Ninety-eight per cent felt that it was beneficial for trainees to move between hospitals during the core years of their advanced training.

CONCLUSIONS

The current Australian gastroenterology training programme is generally adequate in preparing trainees for consultant practice but could be improved by increased emphasis on areas such as private practice, ambulatory gastroenterology and functional gastrointestinal diseases. Exposure to a variety of experiences by training in several different hospitals during core training was universally viewed as being important.

Sarcina-like bacteria associated with bloat in young lambs and calves

Sarcina species are fastidious Gram-positive anaerobic bacteria that occur in cubical packets of eight or more cells. In 2006 to 2007, they were associated with cases of acute abomasal bloat in young lambs and calves. Two incidents were in lambs aged three to six weeks that were found dead, with one or two cases in each of a group of 15 and 100 lambs. Three incidents were recorded in small groups of calves up to 10 days of age, two cases in each incident, with the calves found dead or dying after a short illness characterised by bloat. Their gross lesions included emphysema and oedema of the abomasal wall, mucosal hyperaemia and haemorrhage, and rupture of the abomasum. Histological lesions included abomasitis with congestion, haemorrhage, emphysema and oedema. Bacteria characteristic of Sarcina species were observed in sections associated with the superficial mucosa of these cases, but the bacteria were not detected in cultures.

Chronic hepatitis B: recommendations for therapy based on the natural history of disease in Australian patients

BACKGROUND

Chronic hepatitis B infection (CHB) is a major health problem in Australia and worldwide. CHB is associated with significant long-term morbidity and mortality. Well tolerated treatment is now available, however the development of resistance is common and the optimal timing of treatment is yet to be determined. Identifying the factors that influence the natural history of CHB may help determine which patients need treatment and when to start it.

OBJECTIVE

To determine the demographics, clinical features and virological profile of Australian patients infected with CHB and the influence of these factors on disease activity and severity.

STUDY DESIGN

Review of prospectively collected demographic, clinical and virological features of all patients positive for hepatitis B surface antigen (HBsAg) for more than 6 months who were referred to St. Vincent's Hospital liver clinics. Age, sex and ethnicity were correlated with hepatitis B e antigen status (HBeAg), HBV replication status (ALT and HBV DNA), genotype and liver histology.

RESULTS

703 chronic hepatitis B surface antigen positive patients were identified. The patients were predominantly male with an average age of 44. Eighty two percent of patients were born overseas, primarily from Asian (65%) and Mediterranean countries (14%). Two thirds (426) had an elevated ALT (median 79) at presentation. HBeAg was positive in 37%. Active viral replication, defined as abnormal ALT or positive HBVDNA, was present in 74%, 48% of whom were HBeAg negative. In a subset of 103 patients genotyped, 8% had genotype A, 29% B, 41% C and 22% D. Genotype correlated with ethnicity; patients infected with genotypes A were predominantly Caucasian, B and C were Asian, and D were Mediterranean. Of 296 (42%) patients who underwent liver biopsy, 76 (27%) had advanced fibrosis. Advanced fibrosis was associated with increasing age and Mediterranean ethnicity.

CONCLUSION AND RECOMMENDATIONS

Perinatal or early childhood transmission is predominant mode of infection in Australia. Two thirds of this cohort had active replication and were at increased risk of developing cirrhosis and/or hepatoma. Advanced disease was associated with age and ethnicity. HBeAg negative CHB accounts for almost half of all those with active viral replication. This parallels the rise in this form of CHB in Asia and the Mediterranean basin. Screening should be offered to people born in, or with parents born in areas of high endemnicity. To detect the development of active disease, patients with positive HBsAg but normal ALT should have liver function tests done 6 monthly and those with elevated ALT should be referred for consideration of therapy, irrespective of HBeAg status.

Survivin interacts with Smac/DIABLO in ovarian carcinoma cells but is redundant in Smac-mediated apoptosis

Abnormalities in the control and execution of apoptosis are seen in many malignancies, including ovarian carcinoma. Many of these abnormalities involve the mitochondrial pathway of apoptosis, including overexpression of BIR-containing inhibitor of apoptosis protein (IAP) family proteins as well as dysregulated apoptosome function. We sought to stimulate the mitochondrial pathway of apoptosis by constructing a recombinant adenovirus encoding mature, processed Smac/DIABLO (Ad CMV tSmac), the second mitochondrial activator of caspases. Transfection of ovarian carcinoma cells with Ad CMV tSmac leads to increasing apoptosis in a dose-dependent manner. By contrast, transfection of IOSE397 immortalized normal ovarian surface epithelial cells does not cause apoptosis. We also show that the processed form of Smac is primarily expressed in the cytosol of ovarian carcinoma cells. Smac co-immunoprecipitates with both survivin and XIAP and stimulates survivin, but not XIAP, down-regulation. This down-regulation does not result from transcriptional changes, as determined by quantitative real-time PCR, but cycloheximide treatment indicates that survivin half-life is reduced from 6 to 2 h, which is secondary to ubiquitination and proteasomal degradation. RNA interference, however, suggests that survivin does not act to inhibit Smac-mediated apoptosis, which is confirmed by cotransfection with the phosphorylation mutant, survivin T34A. Finally, intraperitoneal delivery of Ad CMV tSmac increases median survival of mice bearing human ovarian carcinoma xenografts. We believe that expression of Smac/DIABLO can stimulate the intrinsic pathway of apoptosis in ovarian carcinoma without damaging normal ovarian tissue and therefore has therapeutic potential.

Gene therapy progress and prospects: cancer gene therapy using tumour suppressor genes

Targeting tumour suppressor gene pathways is an attractive therapeutic strategy in cancer. Since the first clinical trial took place in 1996, at least 20 other trials have investigated the possibility of restoring p53 function, either alone or in combination with chemotherapy, but with limited success. Other recent clinical trials have sought to harness abnormalities in the p53 pathway to permit tumour-selective replication of adenoviral vectors such as dl1520 (Onyx-015). Other tumour suppressor genes, such as retinoblastoma (Rb) and PTEN (phosphatase, tensin homologue, deleted on chromosome 10), are the targets for imminent clinical trials, while microarray technologies are revealing multiple new genes that are potential targets for future gene therapy.

Evaluation of Helicobacter species in inflammatory bowel disease

BACKGROUND

Bacteria have been implicated in the pathogenesis of inflammatory bowel disease. Helicobacter species have been shown to cause colitis in animal models and have been identified in human diarrhoeal illness and Crohn's disease.

AIM

To determine whether Helicobacter species are present in human inflammatory bowel disease tissue.

METHODS

Thirty patients undergoing colonoscopy for clinical reasons were studied. Nine had Crohn's disease, 11 had ulcerative colitis and 10 had histologically normal colons. Tissue was snap-frozen at -70 degrees C. DNA was extracted and examined by five different polymerase chain reaction (PCR) assays that were either genus or species specific for Helicobacter.

RESULTS

Analyses of colonic biopsies by two Helicobacter genus-specific PCR assays, two H. pylori-specific assays and a PCR assay designed to amplify fragments of 'H. heilmannii'-like organisms demonstrated that product was not generated by any test. Internal control PCR demonstrated that PCR results for the five assays were not negative due to the presence of residual substances inhibitory to PCR.

CONCLUSIONS

Helicobacter species were not identified in this study, using multiple PCRs to eliminate the problems of non-specific cross-reaction. This suggests that Helicobacter species do not play a role in the pathogenesis of inflammatory bowel disease.

The clinical course of fistulating Crohn's disease

AIM

To determine the clinical characteristics, management and outcome of Crohn's fistulas from the time of first presentation.

METHODS

Patients treated for fistulas 6 years previously were assessed for disease demographics, fistula characteristics and treatment from first presentation to final follow-up.

RESULTS

Eighty-seven patients with active Crohn's fistulas were evaluated. The median age was 35 years and the median duration of Crohn's disease was 8 years at study entry. Disease was ileo-colonic or colonic in 85%, and 65% had rectal involvement. A single fistula was present in one-third and multiple fistulas in two-thirds; 65% of fistulas were perianal; 80% of fistulas were complex. After a median follow-up from the last treatment of 5.9 years, 68% of patients showed healing of all fistulas, 18% showed healing of some fistulas and 14% showed no healing of fistulas. The fistula site did not influence healing. Perianal and recto-vaginal fistulas took a median of 2.6 years to heal. Half of the complex fistulas required a stoma, resection or proctectomy.

CONCLUSIONS

Healing is usually achieved. However, morbidity is great and healing is slow. Proctectomy is required in one-fifth of patients, and perineal healing is often slow. Defining the perianal fistula anatomy as complex or simple determines the likelihood of healing and the type of surgical approach required.

The clinical course of fistulating Crohn's disease

AIM

To determine the clinical characteristics, management and outcome of Crohn's fistulas from the time of first presentation.

METHODS

Patients treated for fistulas 6 years previously were assessed for disease demographics, fistula characteristics and treatment from first presentation to final follow-up.

RESULTS

Eighty-seven patients with active Crohn's fistulas were evaluated. The median age was 35 years and the median duration of Crohn's disease was 8 years at study entry. Disease was ileo-colonic or colonic in 85%, and 65% had rectal involvement. A single fistula was present in one-third and multiple fistulas in two-thirds; 65% of fistulas were perianal; 80% of fistulas were complex. After a median follow-up from the last treatment of 5.9 years, 68% of patients showed healing of all fistulas, 18% showed healing of some fistulas and 14% showed no healing of fistulas. The fistula site did not influence healing. Perianal and recto-vaginal fistulas took a median of 2.6 years to heal. Half of the complex fistulas required a stoma, resection or proctectomy.

CONCLUSIONS

Healing is usually achieved. However, morbidity is great and healing is slow. Proctectomy is required in one-fifth of patients, and perineal healing is often slow. Defining the perianal fistula anatomy as complex or simple determines the likelihood of healing and the type of surgical approach required.

Response of fistulating Crohn's disease to infliximab treatment assessed by magnetic resonance imaging

AIMS

To assess fistula track healing after infliximab treatment using magnetic resonance imaging.

METHODS

Magnetic resonance imaging and clinical evaluation were performed before and after three infliximab infusions given over a 6-week period. Magnetic resonance images were evaluated for abscesses and fistula tracks. Paired magnetic resonance image examinations were rated 'better', 'unchanged' or 'worse'. Magnetic resonance imaging and clinical outcomes were then compared.

RESULTS

Of the 12 referred patients, pre-treatment magnetic resonance imaging detected abscesses in three (two not treated). Of the 10 treated patients, seven had peri-anal fistulas, two of whom also had recto-vaginal fistulas, and three had abdominal wall entero-cutaneous fistulas. After infliximab, four were in remission, one had a response and five were non-responders. One developed a peri-anal abscess. Magnetic resonance imaging improved in six, was unchanged in two and was worse in two. In four of the six with improvement in magnetic resonance imaging, the fistula track resolved, but two of these had clinically persistent entero-cutaneous fistulas. The clinical outcome and magnetic resonance imaging correlated in seven of the 10 patients; in three (two entero-cutaneous and one peri-anal), there was discordance.

CONCLUSIONS

Magnetic resonance imaging identifies clinically silent sepsis. Fistulas may persist despite clinical remission. Clinical response to infliximab and clinical correlation with magnetic resonance imaging were poor in patients with abdominal entero-cutaneous fistulas.

Randomized, placebo-controlled clinical trial of oral azithromycin prophylaxis against respiratory infections in a high-risk, young adult population

Military Special Forces trainees undergo intense psychological and physical stressors that often lead to respiratory infection. During 1998-2000, 477 Navy Special Forces trainees were enrolled in a double-blind trial of oral azithromycin (1 g given weekly) plus a placebo injection, compared with benzathine penicillin G (1.2 million U) plus azithromycin placebo tablets. Among the 464 subjects with complete data, 44 developed acute respiratory infection (20 with pneumonia) during the 2 weeks of most intense training; of these subjects, 12 (27.3%) had evidence of Chlamydia pneumoniae infection and 7 (15.9%) had evidence of Mycoplasma pneumoniae infection. Trainees who received azithromycin were less likely than were trainees who received benzathine penicillin G to develop acute respiratory infection (risk ratio, 0.50; 95% confidence interval [CI], 0.28-0.92) and less likely at the end of training to report episodes of breathing difficulty (odds ratio [OR], 0.59; 95% CI, 0.34-1.01) or sore throat (OR, 0.66; 95% CI, 0.41-1.05). Compared with benzathine penicillin G prophylaxis, weekly oral azithromycin was superior in preventing respiratory infection in this population at transient high risk.

Model process for removal of caseins from milk of transgenic animals

We describe a method for selective removal of caseins from milk. The method was developed as a model for transgenic milk processing. Raw cow milk spiked with nonmilk proteins was chosen as the model to resemble transgenic animal milk containing recombinant proteins. The most important elements of the process are (1) "deconstruction" of casein micelles in milk by destroying their Ca(2+) core using a chelating agent (EDTA), thus freeing any protein that might be entrapped in casein aggregates, and (2) "reconstruction" of micelles by providing them with a new Ca(2+) core, thus precipitating them away from the whey proteins, and the protein of interest. Calcium phosphate particles (CAP) were used to reform the disrupted casein micelles. The crystal clear supernatant fraction generated by this method provided >90% recovery and 6- to 13-fold concentration of the desired protein. Product-rich supernatant contained no detectable casein residues, as silver-stained SDS-PAGE and Western blot analyses demonstrated.