Virtual curriculum delivery in the COVID-19 era: the pediatric surgery boot camp v2.0

PURPOSE

We evaluated the impact of a virtual Pediatric Surgery Bootcamp curriculum on resource utilization, learner engagement, knowledge retention, and stakeholder satisfaction.

METHODS

A virtual curriculum was developed around Pediatric Surgery Milestones. GlobalCastMD delivered pre-recorded and live content over a single 10-h day with a concluding social hour. Metrics of learner engagement, faculty interaction, knowledge retention, and satisfaction were collected and analyzed during and after the course.

RESULTS

Of 56 PS residencies, 31 registered (55.4%; 8/8 Canadian and 23/48 US; p = 0.006), including 42 learners overall. The virtual BC budget was $15,500 (USD), 54% of the anticipated in-person course. Pre- and post-tests were administered, revealing significant knowledge improvement (48.6% [286/589] vs 66.9% [89/133] p < 0.0002). Learner surveys (n = 14) suggested the virtual BC facilitated fellowship transition (85%) and strengthened peer-group camaraderie (69%), but in-person events were still favored (77%). Program Directors (PD) were surveyed, and respondents (n = 22) also favored in-person events (61%). PDs not registering their learners (n = 7) perceived insufficient value-added and concern for excessive participants.

CONCLUSIONS

The virtual bootcamp format reduced overall expenses, interfered less with schedules, achieved more inclusive reach, and facilitated content archiving. Despite these advantages, learners and program directors still favored in-person education.

LEVEL OF EVIDENCE

III.

Factors that influence mental health of university and college students in the UK: a systematic review

Background

Worsening mental health of students in higher education is a public policy concern and the impact of measures to reduce transmission of COVID-19 has heightened awareness of this issue. Preventing poor mental health and supporting positive mental wellbeing needs to be based on an evidence informed understanding what factors influence the mental health of students.

Objectives

To identify factors associated with mental health of students in higher education.

Methods

We undertook a systematic review of observational studies that measured factors associated with student mental wellbeing and poor mental health. Extensive searches were undertaken across five databases. We included studies undertaken in the UK and published within the last decade (2010–2020). Due to heterogeneity of factors, and diversity of outcomes used to measure wellbeing and poor mental health the findings were analysed and described narratively.

Findings

We included 31 studies, most of which were cross sectional in design. Those factors most strongly and consistently associated with increased risk of developing poor mental health included students with experiences of trauma in childhood, those that identify as LGBTQ and students with autism. Factors that promote wellbeing include developing strong and supportive social networks. Students who are prepared and able to adjust to the changes that moving into higher education presents also experience better mental health. Some behaviours that are associated with poor mental health include lack of engagement both with learning and leisure activities and poor mental health literacy.

Conclusion

Improved knowledge of factors associated with poor mental health and also those that increase mental wellbeing can provide a foundation for designing strategies and specific interventions that can prevent poor mental health and ensuring targeted support is available for students at increased risk.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13943-x.

A population-based analysis of the presentation and outcomes of pediatric patients with osteosarcoma in Canada: a report from CYP-C

Background:

Frequently occurring in adolescents, osteosarcoma is the most common primary malignant bone disease, with a reported 15% of patients who present with metastasis. With advances in imaging and improvements in surgical care, an updated analysis is warranted on the outcomes of pediatric patients with osteosarcoma.

Methods:

We completed a retrospective review of pediatric patients who presented with osteosarcoma between 2001 and 2017, using The Cancer in Young People in Canada (CYP-C) national database. Data on 304 patients aged younger than 15 years were analyzed.

Results:

The proportion of patients who presented with metastasis was 23.0%. The overall 5-year survival (OS) for patients who presented with metastasis was 37.4%. Overall survival and event-free survival (EFS) were lower in these patients than in patients with localized disease (hazard ratio [HR] 4.3, p < 0.0001 and HR 3.1, p < 0.0001). For patients who presented with metastatic disease, the OS for those undergoing an operative intervention was 44.1% compared with 17.6% for those who did not undergo resection (p < 0.0001).

Conclusion:

The proportion of patients who presented with metastatic osteosarcoma in our population is higher than previously reported. Overall outcomes of patients with metastatic disease have not changed. Our data reaffirm a role for surgical resection in patients with metastasis with a need to explore new treatment strategies to improve the overall prognosis of these patients.

A survey of management preferences for bladder exstrophy and cloacal anomalies among Canadian pediatric surgeons and urologists

PURPOSE

This study examined the current referral patterns and preferences of Canadian Association of Paediatric Surgeons (CAPS) and Pediatric Urologists of Canada (PUC) members for management of bladder exstrophy and cloacal anomalies (BECA).

METHODS

We invited CAPS and PUC members to participate in an online survey using RedCap. Demographic variables, years in practice, current referral patterns and local expertise at the participants' institution were collected. Participants' preferences towards three distinct referral models were assessed using Likert scales: no centralization of care, centralization in one or two national centres of excellence, or a consortium-based approach.

RESULTS

There were 82 survey respondents (2/3 were CAPS members, 35.4% female, 72% in practice for >10 years). Although >90% of participants agreed/somewhat agreed that surgical volumes impact outcomes, 58% reported not referring out BECA patients for treatment; about 50% recognized the existence of a local dedicated expert. In terms of referral preferences, 84% of participants favoured identification of a few centres with expertise based on geographic location (a consortium-based approach), while only 7% chose a one or two national centres of excellence model. Over half of participants agreed/somewhat agreed with participating in trials of a consortium-based approach in Canada.

CONCLUSION

Most CAPS and PUC members do not refer BECA patients elsewhere for treatment. Nonetheless, most surgeons recognize the importance of volume to improve outcomes and show willingness to participate in trials to concentrate experience; most participants favour a consortium-based approach through identification of a few centres of excellence based on geographic location.

Harmful algal bloom-related 311 calls, Cape Coral, Florida 2018-2019

Harmful algal blooms (HABs) can adversely impact water quality and threaten human and animal health. People working or living along waterways with prolonged HAB contamination may face elevated toxin exposures and breathing complications. Monitoring HABs and potential adverse human health effects is notoriously difficult due to routes and levels of exposure that vary widely across time and space. This study examines the utility of 311 calls to enhance HAB surveillance and monitoring. The study focuses on Cape Coral, FL, USA, located along the banks of the Caloosahatchee River and Estuary and the Gulf of Mexico. The wider study area experienced a prolonged cyanobacteria bloom in 2018. The present study examines the relationship between weekly water quality characteristics (temperature, dissolved oxygen, pH, microcystin-LR) and municipal requests for information or services (algal 311 calls). Each 1 μg/L increase in waterborne microcystin-LR concentrations corresponded with 9% more algal 311 calls (95% confidence interval: 1.03-1.15, p = 0.002). The results suggest water quality monitoring and the 311 dispatch systems may be further integrated to improve public health surveillance.

A comparison of balloon and nonballoon gastrostomy tubes in children

PURPOSE

The purpose of this study was to compare primary outcomes following insertion of balloon and nonballoon gastrostomy tubes (G-tubes).

METHODS

A retrospective chart review over a 5-year period comparing the need for emergency, radiologic, or operative interventions between balloon and nonballoon G-tube devices was performed.

RESULTS

145 patient charts were reviewed (46.8% female, 53.1% male). The indication for G-tube insertion was failure to thrive in 83.4%. Average age at insertion was 4.3 years (0-17.9 years). 37.2% had a balloon type G-tube, and 62.8% had a nonballoon type. Patients with a nonballoon device had 1.14 (0-15) ER visits related to the G-tube vs. 0.48 (0-6) visits with a balloon device. Of the ER visits for patients with a nonballoon device, 26.9% were replaced in ER, 38.5% in radiology, and 34.6% required an operation for replacement. For patients with a balloon device, 47.8% were replaced in the ER, 52.2% were replaced in radiology (GJ), and none required operative replacement. The majority of patients who initially had a nonballoon G-tube placed required a second operation for device change (95.7%). Patients with nonballoon devices required significantly more operations (average 2.55, range 0-16) vs patients with balloon devices (average 0.40, range 0-3) (p < .05).

CONCLUSIONS

Balloon-type G-tubes require less ER visits and operative interventions compared to nonballoon G-tubes.

LEVEL OF EVIDENCE

C.

A transition to discipline curriculum for pediatric surgery trainees: Evaluation of a pediatric surgery boot camp from 2017 to 2018

INTRODUCTION

Boot camps seek to impart knowledge and skills for individuals entering new roles. We sought to evaluate knowledge, skills, and confidence of in-coming pediatric surgery trainees with a 2.5-day pediatric surgery boot camp.

METHODS

A curriculum included key aspects of pediatric surgery delivered during interactive lectures, small group discussions, and simulation. With REB approval, participant demographics were collected. Pre- and posttests assessed knowledge and trainee confidence. Comparative statistics and multivariate analysis of variance (MANOVA) were performed.

RESULTS

Between 2017 and 2018, 16 individuals from North American pediatric surgery training programs participated in two boot camps. Ten had North American general surgery training, and eleven had no pediatric surgery exposure ≥1 year prior. All participants expressed increased confidence with course material after boot camp [F(18,11) = 3.137;p < 0.05]. Performance improved significantly (pre- vs. posttests, 47.0% vs. 62.4%; p < 0.05). MANOVA between faculty and trainees demonstrated agreement on the value of individual sessions [F(15,3) = 0.642;p = 0.76]. Neonatal bowel obstruction, gastrostomy tube complications, esophageal atresia, pain management, and informed consent were rated most useful.

CONCLUSION

Trainees and teaching faculty considered the boot camp valuable. Trainees demonstrated significant improvements in core knowledge and confidence. The initial pediatric surgery boot camp experience shows promise in facilitating the transition to discipline for new trainees.

STUDY TYPE

Prospective treatment study.

LEVEL OF EVIDENCE

IV.

Small bowel obstruction due to ingestion of rubber balls

We report a case of a 10-month-old girl who presented with a 10-day history of emesis that became bilious on the last day. The initial evaluation suggested small bowel obstruction. An upper gastrointestinal study confirmed the normal location of the duodenojejunal junction with normal rotation and no evidence of midgut volvulus. Ultrasound (US) evaluation demonstrated two intraluminal lesions that do not follow the typical features of solid or cystic lesions. Two rubber balls were found at surgery to be responsible for the small bowel obstruction. Foreign body ingestion is common in children, but this case demonstrates a unusual foreign object to be ingested as well as the US appearance of this particular foreign body.

A comparison of outcomes between laparoscopic and open appendectomy in Canada

SUMMARY

The benefit of a laparoscopic approach to appendectomy continues to be debated. We compared laparoscopic (LA) with open appendectomy (OA) for appendicitis in Canada using the Canadian Institute for Health Information database (2004-2008). The odds of female patients undergoing LA were 1.26 times higher than the odds of male patients, and the odds of patients with nonperforated pathology undergoing LA were 1.38 times higher than the odds of those with perforated pathology. Increasing comorbidities were associated with OA. While LA is becoming more frequent, the associated length of stay, postoperative complication rate and mortality are clearly lower than for OA. As a result, we support the continued increase in use of LA with regard to both safety and outcomes.

Targeted needs assessment for a transitional "boot camp" curriculum for pediatric surgery residents

INTRODUCTION

Transition periods in medical education are associated with increased risk for learners and patients. For pediatric surgery residents, the transition to training is especially difficult as learners must adjust to new patient populations. In this study we perform a targeted needs assessment to determine the ideal content and format of a pediatric surgery boot camp to facilitate the transition to residency.

METHODS

A needs assessment survey was developed and distributed to pediatric surgery residents and staff across North America. The survey asked participants to rank 30 pediatric surgical diagnoses, 20 skills, and 11 physiological topics on "frequency" and "importance". Items were then ranked using empirical methods. The survey also evaluated the preferred boot camp format.

RESULTS

In total, 12 residents and 23 staff completed the survey. No significant differences were identified between staff and residents in survey responses. The top 5 topics identified for inclusion in a boot camp were: (1) fluid and electrolyte management, (2) appendicitis, (3) pediatric hernias, (4) nutrition and (5) pain management. The preferred format for a boot camp was 3-4days in duration applying a blend of educational methods.

CONCLUSIONS

Based on the results of the needs assessment survey, a novel pediatric surgery boot camp curriculum can be developed.

Effects of Postgraduate Medical Education "Boot Camps" on Clinical Skills, Knowledge, and Confidence: A Meta-Analysis

BACKGROUND

Throughout their medical education, learners face multiple transition periods associated with increased demands, producing stress and concern about the adequacy of their skills for their new role.

OBJECTIVE

We evaluated the effectiveness of boot camps in improving clinical skills, knowledge, and confidence during transitions into postgraduate or discipline-specific residency programs.

METHODS

Boot camps are in-training courses combining simulation-based practice with other educational methods to enhance learning and preparation for individuals entering new clinical roles. We performed a search of MEDLINE, CINAHL, PsycINFO, EMBASE, and ERIC using boot camp and comparable search terms. Inclusion criteria included studies that reported on medical education boot camps, involved learners entering new clinical roles in North American programs, and reported empirical data on the effectiveness of boot camps to improve clinical skills, knowledge, and/or confidence. A random effects model meta-analysis was performed to combined mean effect size differences (Cohen's d) across studies based on pretest/posttest or comparison group analyses.

RESULTS

The search returned 1096 articles, 15 of which met all inclusion criteria. Combined effect size estimates showed learners who completed boot camp courses had significantly "large" improvements in clinical skills (d  =  1.78; 95% CI 1.33-2.22; P < .001), knowledge (d  =  2.08; 95% CI 1.20-2.96; P < .001), and confidence (d  =  1.89; 95% CI 1.63-2.15; P < .001).

CONCLUSIONS

Boot camps were shown as an effective educational strategy to improve learners' clinical skills, knowledge, and confidence. Focus on pretest/posttest research designs limits the strength of these findings.

A large-scale, rapid public health response to rabies in an organ recipient and the previously undiagnosed organ donor

This article describes and contrasts the public health response to two human rabies cases: one organ recipient diagnosed within days of symptom onset and the transplant donor who was diagnosed 18 months post-symptom onset. In response to an organ-transplant-related rabies case diagnosed in 2013, organ donor and recipient investigations were conducted by multiple public health agencies. Persons with potential exposure to infectious patient materials were assessed for rabies virus exposure. An exposure investigation was conducted to determine the source of the organ donor's infection. Over 100 persons from more than 20 agencies spent over 2700 h conducting contact investigations in healthcare, military and community settings. The 564 persons assessed include 417 healthcare workers [5.8% recommended for post-exposure prophylaxis (PEP)], 96 community contacts (15.6% recommended for PEP), 30 autopsy personnel (50% recommended for PEP), and 21 other persons (4.8% recommended for PEP). Donor contacts represented 188 assessed with 20.2% recommended for PEP, compared with 5.6% of 306 recipient contacts recommended for PEP. Human rabies cases result in substantial use of public health and medical resources, especially when diagnosis is delayed. Although rare, clinicians should consider rabies in cases of encephalitis of unexplained aetiology, particularly for cases that may result in organ donation.

Clinical manifestations of tension pneumothorax: protocol for a systematic review and meta-analysis

BACKGROUND

Although health care providers utilize classically described signs and symptoms to diagnose tension pneumothorax, available literature sources differ in their descriptions of its clinical manifestations. Moreover, while the clinical manifestations of tension pneumothorax have been suggested to differ among subjects of varying respiratory status, it remains unknown if these differences are supported by clinical evidence. Thus, the primary objective of this study is to systematically describe and contrast the clinical manifestations of tension pneumothorax among patients receiving positive pressure ventilation versus those who are breathing unassisted.

METHODS/DESIGN

We will search electronic bibliographic databases (MEDLINE, PubMed, EMBASE, and the Cochrane Database of Systematic Reviews) and clinical trial registries from their first available date as well as personal files, identified review articles, and included article bibliographies. Two investigators will independently screen identified article titles and abstracts and select observational (cohort, case-control, and cross-sectional) studies and case reports and series that report original data on clinical manifestations of tension pneumothorax. These investigators will also independently assess risk of bias and extract data. Identified data on the clinical manifestations of tension pneumothorax will be stratified according to whether adult or pediatric study patients were receiving positive pressure ventilation or were breathing unassisted, as well as whether the two investigators independently agreed that the clinical condition of the study patient(s) aligned with a previously published tension pneumothorax working definition. These data will then be summarized using a formal narrative synthesis alongside a meta-analysis of observational studies and then case reports and series where possible. Pooled or combined estimates of the occurrence rate of clinical manifestations will be calculated using random effects models (for observational studies) and generalized estimating equations adjusted for reported potential confounding factors (for case reports and series).

DISCUSSION

This study will compile the world literature on tension pneumothorax and provide the first systematic description of the clinical manifestations of the disorder according to presenting patient respiratory status. It will also demonstrate a series of methods that may be used to address difficulties likely to be encountered during the conduct of a meta-analysis of data contained in published case reports and series. PROSPERO registration number: CRD42013005826.

The impact of multi-disciplinary intestinal rehabilitation programs on the outcome of pediatric patients with intestinal failure: a systematic review and meta-analysis

BACKGROUND

Pediatric intestinal failure (IF) is a complex clinical problem requiring coordinated multi-disciplinary care. Our objective was to review the evidence for the benefit of intestinal rehabilitation programs (IRP) in pediatric IF patients.

METHODS

A systematic review was performed on Medline (1950-2012), Pubmed (1966-2012), and Embase (1980-2012) conference proceedings and trial registries. The terms short bowel syndrome, intestinal rehabilitation, intestinal failure, patient care teams, and multi-disciplinary teams were used. Fifteen independent studies were included. Three studies that were cohort studies, including a comparison group, were included in a meta-analysis.

RESULTS

Compared to historical controls (n=103), implementation of an IRP (n=130) resulted in a reduction in septic episodes (0.3 vs. 0.5 event/month; p=0.01) and an increase in overall patient survival (22% to 42%). Non-significant improvements were seen in weaning from PN (RR=1.05, 0.88-1.25, p=0.62), incidence of IFALD (RR=0.2, 0-17.25, p=0.48), and relative risk of liver transplantation (3.99, 0.75-21.3, p=0.11). Other outcomes reported included a reduction in calories from parenteral nutrition (100% to 32%-56%), earlier surgical/transplant evaluation, and improved coordination of patient care.

CONCLUSION

For pediatric IF patients, IRPs are associated with reduced morbidity and mortality. Standardized clinical practice guidelines are necessary to provide uniform patient care and outcome assessment.

Toxin producing Vibrio cholerae O75 outbreak, United States, March to April 2011

The Florida Department of Health, Florida, United States, is investigating a Vibrio cholerae O75 outbreak. Ten cases with disease onsets from 23 March to 13 April 2011, presented with gastrointestinal symptoms of diarrhoea, nausea, vomiting, cramps, chills, and/or fever, after consuming raw or lightly cooked oysters harvested from Apalachicola Bay, Florida. Symptoms were milder than those during outbreaks of epidemic (serogroup O1 and O139) Vibrio cholerae; no case required rehydration treatment or hospitalisation.

Toxin producing Vibrio cholerae O75 outbreak, United States, March to April 2011

The Florida Department of Health, Florida, United States, is investigating a Vibrio cholerae O75 outbreak. Ten cases with disease onsets from 23 March to 13 April 2011, presented with gastrointestinal symptoms of diarrhoea, nausea, vomiting, cramps, chills, and/or fever, after consuming raw or lightly cooked oysters harvested from Apalachicola Bay, Florida. Symptoms were milder than those during outbreaks of epidemic (serogroup O1 and O139) Vibrio cholerae; no case required rehydration treatment or hospitalisation.

Cytotoxicity, drug combinability, and biological correlates of ABT-737 against acute lymphoblastic leukemia cells with MLL rearrangement

BACKGROUND

ABT-737 is a BH3 mimetic small-molecule inhibitor that binds with high affinity to Bcl-2 to induce apoptosis in malignant cells and has shown promise as an effective anti-leukemic agent in pediatric preclinical tests. This study focuses on the effects of ABT-737 on leukemia cells with MLL rearrangement and identifies some of the biological correlates of its activity.

PROCEDURE

Cells were cultured in the presence of increasing concentrations of ABT-737 alone or in combination with other agents. After 4 days in culture, cell growth inhibition was measured by Alamar blue assay. The expression and activation of potential intracellular targets of ABT-737 activity were determined by Western blot analysis.

RESULTS

Significant Bcl-2 expression was detected in all infant leukemia cells investigated. ABT-737 induced cell death in all cell lines studied although the IC(50) values differed somewhat between cell lines. Western blot analysis identified the effects of ABT-737 on survival and apoptosis-regulatory proteins PARP, caspase-8, and cytochrome-c. Drug combination studies indicated synergy with distinct anti-neoplastic agents, including the multi-tyrosine kinase inhibitor sunitinib. This effective drug synergy appears to be mediated by the combined inhibition of Bcl-2 and intracellular signaling pathways.

CONCLUSIONS

We describe the in vitro studies to demonstrate the activity and drug combinability of ABT-737 against MLL rearranged leukemia cells. In addition, identification of the molecular changes that occur in the presence of ABT-737 provides information regarding effective target validation and target modulation analyses in future clinical trials.

Analysis of multiple growth regulatory proteins using dissociable staining antibody arrays on solid tumor biopsy specimens

Growth of tumor cells is often a function of deregulated growth factor receptors and their corresponding intracellular signalling molecules. The dissociable antibody staining arrays have the versatility to rapidly identify the expression, activation, and localization of such molecules and pathways in biopsy specimens. This report describes a protocol to quantify the activity of a panel of signalling molecules in Wilms tumor biopsy specimens and surrounding nonmalignant renal cells. We propose that this technique can be used to rapidly identify multiple markers and may aid in the study of aberrant growth regulatory mechanisms and potential targets for therapeutics from pathologic specimens.

Effect of Infectious Bursal Disease Virus Insult on Iron, Copper, and Zinc Concentration in Liver, Bursa of Fabricius, Spleen, Pancreas, and Serum of Chickens

The effect of a systemic disease on the dynamics of iron, zinc, and copper in chickens fed ad libitum was examined by infecting 10-day-old specific pathogen-free chickens with infectious bursal disease virus (IBDV). Liver, bursa of Fabricius, pancreas, spleen, and serum were sampled in 10 controls and 10 challenged chickens at 3-day intervals postinfection (PI) for 15 days. The samples were analyzed using atomic absorption spectroscopy. Serum levels were similar to that reported in the literature. Concentrations of iron and zinc did not change significantly in the pancreas, but there was an increase in copper in infected pancreatic tissue on days 9 and 15 PI. Iron concentration in the spleen showed a significant increase on days 6, 9, and 15 PI, whereas zinc was only significantly increased on day 15 PI. There was no significant change in copper concentrations in the spleens of infected chickens vs. controls. This finding is in line with previously reported data. The results showed that the liver was not a major tissue where iron and zinc were sequestered, as previous data have shown in mammals. Instead, the bursa of Fabricius had significantly increased levels of both iron and zinc in infected tissue vs. control tissue from 9 days PI on. Furthermore, the bursa had increased levels of copper in the latter portion of the study. These findings suggest that the bursa of Fabricius rather than the liver is the major organ for metallic ion sequestering during IBDV infection.

Marijuana use and social networks in a community outbreak of meningococcal disease

BACKGROUND

We examined the role of social networks and marijuana smoking in a community outbreak of infections due to Neisseria meningitidis.

METHODS

We interviewed all patients and their contacts. Isolates were tested by pulsed field electrophoresis and multilocus enzyme electrophoresis.

RESULTS

Nine cases of meningococcal disease occurred in the outbreak; isolates from seven cases with positive cultures were identical. Multiple overlapping social networks were found for case-patients and their contacts. All case-patients were linked by the marijuana-related activities of their contacts.

CONCLUSION

Investigation of social networks and marijuana exposure might help identify close contacts of patients with meningococcal disease and help prevent secondary infections.

Modulation of the cleavage of the gastrin precursor by prohormone phosphorylation

BACKGROUND & AIMS

Amidated gastrins are acid secretagogues and growth factors. Their precursor, progastrin, is a growth factor but not a secretagogue. Cleavage of progastrin at Arg94/95 determines the expression of these two alternative patterns of biological activity. We examined the hypothesis that cleavage at Arg94/95 is regulated by phosphorylation of the adjacent Ser96 residue.

METHODS

Hamster insulinoma cells were stably transfected with wild-type rat preprogastrin and phosphorylation site mutants; biosynthesis was studied by a pulse-chase protocol.

RESULTS

Rates of cleavage at Arg94/95 were increased in Ser96-->Ala compared with wild-type progastrin. Mutation of Glu98 to Ala inhibited incorporation of [32P]phosphate into progastrin and increased the rate of cleavage at Arg94/95. Conversely, mutation of Ser96 to Asp reduced rates of cleavage at Arg94/95. Depletion of calcium stores decreased phosphorylation of Ser96 and increased cleavage at Arg94/95. Modulation of Ser96 phosphorylation also directly influenced the ratio of progastrin-cleavage products (progastrin/CFP; G17Gly/G34Gly) secreted into the medium.

CONCLUSIONS

Phosphorylation of progastrin is dependent on calcium stores, determines prohormone cleavage rates, and thereby controls the production of the alternative active products of preprogastrin translation.

Management of the contralateral testis in patients with testicular germ cell cancer

Patients with testicular germ cell tumours (TGCT) are at increased risk of developing a tumour in the contralateral testis. Such a tumour may be preceded by carcinoma in situ (CIS), which is more common in patients with infertility, atrophic testis or a history of cryptorchism. Of 1219 patients with TGCT seen at the Royal Marsden Hospital between 1962 and 1984 in whom the contralateral testis was managed by surveillance, 38 (3.1%) developed a second tumour and 8 died of germ cell tumours. Seventeen of 26 assessable patients (65%) exhibited at least one of the known aetiological risk factors for carcinoma in situ. Diagnosis of carcinoma in situ may lead to more appropriate management of the contralateral testis.

Magnetic relaxation in blood and blood clots

Nuclear magnetic relaxation rates are measured for whole blood, blood plasma, whole blood clots, and plasma clots in vitro. Relaxation rates are linear in the hematocrit and transverse relaxation rates are significantly greater than longitudinal relaxation rates. Longitudinal relaxation rates measured from 0.01 to 42 MHz for proton Larmor frequencies are found to decline monotonically with increasing magnetic field strength; however, the dispersion curves do not follow a simple Lorentzian behavior, which is anticipated in a suspension of particles in a solution of proteins having a distribution of molecular weights. The transverse relaxation rate is a function of the acquisition parameters, in particular, the choice of TE in either Hahn echo experiments or in echo-train experiments. The origin of this dependence of T2 on TE or the interpulse spacing in an echo train is identified with the exchange of water from inside the red blood cell to the outside and is only an important relaxation mechanism in the case where the blood cell membrane is intact and the cell contains deoxygenated hemoglobin. The dependence of the apparent transverse relaxation rate on the interpulse spacing in a Meiboom-Gill-Carr-Purcell pulse sequence provides the estimate that the mean residence time of water inside the blood cell is about 10 ms. These data provide a sound basis for understanding the dependence of magnetic images on magnetic field strength and the choices of the image acquisition parameters, TE and TR.

Etoposide and cisplatin with or without bleomycin as first-line chemotherapy for patients with small-volume metastases of testicular nonseminoma

Between December 1981 and September 1982, a phase II study of etoposide and cisplatin was carried out in 17 patients with small-volume metastases of testicular nonseminoma to see whether the toxicity associated with bleomycin could be avoided without loss of therapeutic effect. Of 16 evaluable patients followed for 13-23 months (median, 18.5), four failed to achieve complete remission and three had disease progression. Conversely, all 18 equivalent patients treated with bleomycin, etoposide, and cisplatin between January 1981 and November 1982 (observation time, 12-34 months; median, 25) achieved complete remission and have been continuously disease-free since treatment (P = 0.07). The results suggest that bleomycin contributes significantly to the combination chemotherapy for testicular nonseminoma, and although its omission led to a marked reduction in toxicity, loss of therapeutic activity was also apparent. Prolongation of the intervals between cycles of etoposide and cisplatin from 3 to 4 weeks may significantly reduce the effectiveness of the two-drug combination, whereas no evidence of this was seen in patients treated with bleomycin, etoposide, and cisplatin.