Verification of two alternative do-it-yourself equipment respirator seal as COVID-19 protection (VADERS-CoV) : a quality assessment pilot study

Background : During the COVID-19 pandemic, healthcare workers were facing shortage in personal protective equipment, especially adequate respirators. Alternative do-it-yourself respirators emerged, without any proof of protection. Objective : Verify seal potential of two alternative respirators compared to a common FFP2 respirator. Design : Quality assessment pilot study. Setting : Tertiary Care Hospital. Participants : Ten anaesthesiology residents. Interventions : Participants performed quantitative face-fit tests (QNFT) with three respirators to evaluate seal. A common FFP2 “duckbill” respirator was used as baseline (control group). Alternatives tested in this study were an anaesthesia face mask and a full-face modified snorkelling mask with a 3D-printed connector, both in conjunction with a breathing system filter. Main outcome : Non-inferior seal performance of the alternatives over FFP2, assessed by calculated QNFT based on measured individual fit factors, as defined by the Occupational Safety and Health Administration. Results :For each respirator a total of 90 individual fit factor measurements were taken. Within the control group, seal failed in 37 (41%) measurements but only in 10 (11%) within the anaesthesia mask group and in 6 (7%) within the snorkelling mask group (P < 0.001 respectively). However, when calculating the final, mean QNFT results, no difference was found between respirators. Successful QNFT were determined for 5 out of 10 participants in the FFP2 group, for 8 in the anaesthesia mask group (P = 0.25) and for 7 in the snorkelling mask group (P = 0.69). Conclusion : Both do-it-yourself respirators successfully pass QNFT and have the potential to provide non inferior seal compared to a common FFP2 respirator. While anaesthesia masks are easily assembled, snorkelling masks must undergo significant but feasible modifications. Our results suggest that those do-it-yourself respirators seem to be viable alternatives for situations when certified respirators are not available but need further investigation for validation. Trial registration: Clinicaltrials.gov identifier: NCT04375774 Key Points : Question: Can alternative do-it-yourself respirators protect wearers from hazardous aerosols? Findings : Our findings demonstrate that do-it-yourself respirators have the potential to provide non-inferior seal as compared to regular FFP2 personal protective equipment. Meaning : Our real-life situational testing provides evidence that do-it-yourself respirators potentially provide sufficient seal to compete with or even outperform conventional FFP2 respirators and that face-fit testing should be a mandatory safety check in healthcare providers.

An audit of the outcomes of the College of Surgeons general surgery final examinations

BACKGROUND

An audit of the Fellowship of the College of Surgeons (FCS) of South Africa examination results has not been previously performed. The purpose of this study was to review and determine any predictors of outcome (pass or fail).

METHODS

The results of the FCS(SA) final examinations from October 2005 to and including October 2014, were retrieved from the College of Medicine of South Africa database. The current format of the examinations consists of two written essay question papers, an objectively structured clinical examination (OSCE), two clinical cases and two oral examinations. These were retrospectively reviewed and analysed. Predictors of failure or success were determined.

RESULTS

During the 10-year study period, 472 candidates attempted the examinations. A total of 388 (82%) candidates were successful in the written component of the examination and were subsequently invited to participate in the clinical component of the examinations. Overall, 296 (63%) candidates passed and 176 (37%) failed. There were 51 candidates who were invited to the oral examinations despite an average of less than 50% in the two papers, and 34 (67%) failed the overall examination. Similarly, 126 candidates were invited having failed one of the two papers of which 81 (64%) ultimately failed. A total of 49 candidates failed the OSCE, 82% of these candidates failed overall. There were strong correlations between the averages of the papers versus the orals (Spearman ρ = 0.51), the papers versus the cases (Spearman ρ = 0.50), and the papers versus the OSCE (Spearman ρ = 0.55).

CONCLUSION

The written papers are the main determinant of invitation to the second part of the examination. Candidates with marginal scores in the written component had an overall failure rate of 67%. Failing one paper and passing the other, resulted in an overall failure rate of 64%. Failing the OSCE resulted in an overall 82% failure rate. With the high failure rate of candidates with marginal scores and with the inter-examination variability of the papers, it might be prudent to revisit both the process of invitation selection and the decision to continue with the long-form of the written component.

Surgical resources in South Africa: a review of the number of functional operating theatres

BACKGROUND

Surgery has previously been neglected as a development initiative, despite the obvious effect of surgical illnesses on morbidity and mortality. Recently, greater attention has been given to surgical services, as there is growing evidence of cost-effectiveness of surgical interventions. Operating theatre numbers have been used as a measure of surgical capacity, despite there being limitations associated with this use of this metric. This study aims to analyse part of the surgical resources in South Africa.

METHODS

A descriptive analysis of surgical infrastructure in all nine provinces was performed. The total number of functional operating theatres was documented for all public and private hospitals in South Africa. Hospitals were contacted during the period from 1 October 2014 until 31 December 2014.

RESULTS

The results showed 3.59 operating theatres per 100 000 population. This fell below the global average of 6.2 operating theatres per 100 000 as well as other developed countries. Theatres were concentrated in metropolitan areas, and there were a greater number of private operating theatres per insured population than in the uninsured public sector.

CONCLUSION

Strengthening surgical systems will reduce the surgical burden of disease and improve health outcomes globally. Little is known about the available surgical resources such as operating theatre density, although using this metric to evaluate surgical capacity has its limitations.

Is regular exercise an effective strategy for weight loss maintenance?

Weight regain after weight loss is one of the most significant challenges to successful obesity treatment. Regular exercise has long been touted as a strategy for weight loss maintenance, but the lack of clear evidence in clinical trials has caused some to question its effectiveness. In this review, we present the arguments both questioning and in support of exercise as an obesity therapeutic. Our purpose is to bring clarity to the literature, present a unified perspective, and identify the gaps in knowledge that need to be addressed in future studies. Critical questions remain including sex differences, individual variability and compensatory behaviors in response to exercise, exercise adherence, the role of energy flux and the molecular mechanisms mediating the beneficial effects of exercise after weight loss and during weight regain. Future research should focus on these critical questions to provide a more complete understanding of the potential benefits of exercise on weight loss maintenance.

Where are general surgeons located in South Africa?

BACKGROUND

Human resources are the backbone of health-care delivery systems and the lack of surgical workforce in developing countries is often the greatest challenge to providing surgical care. The workforce availability and composition is an important indicator of the strength of the health system. This study aimed to analyse the distribution of general surgeons within South Africa.

METHOD

A descriptive analysis of the general surgical workforce in South Africa was performed. The total number of specialist and non-specialist general surgeons working in the public sector in South Africa was documented between the periods from the 1 October 2014 until 31 December 2014.

RESULTS

There were significant disparities in the number and distribution of general surgeons in South Africa. There were 1.78 specialist general surgeons per 100 000, of which 0.69 per 100 000 specialist general surgeons were working in the public sector. There were 2.90 non-specialist general surgeons per 100 000. There were 6 specialist general surgeons per 100 000 insured population working in the private sector, which is comparable with the United States (US). Urban provinces such as Gauteng, the Western Cape and KwaZulu-Natal had the largest number of specialist general surgeons per 100 000. These areas had the largest number of medical aid beneficiaries and nearly 60% of specialist general surgeons were estimated to work exclusively in the private sector.

CONCLUSION

There was a major shortage of surgical providers in South Africa, and in particular the public sector.

The value of supplementary anatomy workshops for improving undergraduate performance

BACKGROUND

With many anatomy courses within the medical curriculum suffering reductions in lecture and dissection time, supplementary programs in anatomy have shown to improve performance of medical students. This study was conducted to evaluate the efficacy of anatomy workshops on undergraduate anatomy grade performance.

METHOD

From 2012 to 2014, mean anatomy and physiology scores of medical students who attended anatomy workshops were compared to those who did not attend. Furthermore, mean scores in anatomy were also compared between students who attended one workshop to those who attended multiple workshops. Data analyses included comparing mean test scores using Student's t-test for normally distributed data.

RESULTS

A total of 55 medical students were included in this study. Significant differences in both anatomy (p < 0.0001) and physiology (p = 0.0113) scores were found between medical students who attended the anatomy workshops versus those who did not. Similarly, medical students who attended multiple workshops, compared to those that attended a single workshop, obtained significantly higher anatomy grade performance (p = 0.0043).

CONCLUSION

The results of this study are supported by comparable studies that have shown similar improvements in grade performance. In a time where reduced undergraduate medical teaching time is prevalent, supplementary education in the basic sciences, with an emphasis on anatomy, may prove a successful adjunct to the medical curriculum.

10-year review of Africa's first student surgical society - UCT Surgical Society

The UCT Student Surgical Society is an undergraduate surgical society based at the University of Cape Town (UCT) which aims to promote surgical education amongst medical students early in their medical careers. Founded in 2006, this was Africa's first student surgical society and has been joined by other medical schools in Africa also establishing their own undergraduate student surgical societies. In this review of the first 10 years of the society, we describe its objectives, its evolution and its international role.

Factors influencing medical students in pursuing a career in surgery: a cross-sectional survey

BACKGROUND

Many factors play a role in the decision of a medical student to pursue a career in surgery. With a decline in numbers of applications into surgical programmes seen globally, the aim of this study was to determine the factors that influence medical students in pursuing a career in surgery.

METHOD

A descriptive, cross-sectional survey was distributed online to all medical students studying at a tertiary, academic institution. Survey items obtained data on demographics, surgical interest and training, as well as factors affecting a surgical career.

RESULTS

A total of 245 medical students responded, of which 56% were female. The majority (69%) stated they were interested in pursuing a career in surgery. Despite 75% of respondents stating South Africa was a good place for surgical training, females reported significantly higher levels of agreement that surgical training would be better overseas when compared to males (p = 0.027). Overall, 20% were undecided on what surgical specialty they would pursue. The largest proportion of respondents (33%) stated that 'Length of training' was the main barrier to pursuing a career in surgery. Thirtythree (13.5%) respondents reported 'Female-unfriendly' as a barrier, of whom all were female. The greatest motivator to pursuing a career in surgery was 'Hands-on work', stated by 36% of respondents.

CONCLUSION

Though length of surgical training was deemed the principal barrier, the majority of students indicated they would pursue a career in surgery. Despite continued perceptions that surgery poses a female-unfriendly environment as a career, respondents held South African surgical training in high esteem, and were motivated by a clinically hands-on approach. These factors may play an important role in determining methods of improving numbers of surgical applications worldwide.

Inguinal Herniation Containing Bladder, Causing Contralateral Allograft Hydroureteronephrosis-A Case Report and Literature Review

We report the first documented case of an inguinal hernia containing bladder, resulting in contralateral allograft hydroureteronephrosis. A 39-year-old male patient presented with allograft dysfunction, a contralateral inguinoscrotal hernia, and marked hydroureteronephrosis on ultrasound (US). Percutaneous nephrostogram and a retrograde cystogram suggested bladder herniation with incorporation of the contralateral ureteroneocystostomy into the hernia. Paraperitoneal bladder herniation was confirmed at surgery and hernioplasty was performed. Six-week follow-up revealed normal renal function with no sign of hernia recurrence. Despite occurring rarely, transplant ureter or bladder herniation should be considered in the differential diagnosis of hydroureteronephrosis. This case illustrates that the contralateral position of hernia to allograft does not necessarily preclude the hernia as the source of ureteric obstruction.

Genome-wide analysis identifies gain and loss/change of function within the small multigenic insecticidal Albumin 1 family of Medicago truncatula

BACKGROUND

Albumin 1b peptides (A1b) are small disulfide-knotted insecticidal peptides produced by Fabaceae (also called Leguminosae). To date, their diversity among this plant family has been essentially investigated through biochemical and PCR-based approaches. The availability of high-quality genomic resources for several fabaceae species, among which the model species Medicago truncatula (Mtr), allowed for a genomic analysis of this protein family aimed at i) deciphering the evolutionary history of A1b proteins and their links with A1b-nodulins that are short non-insecticidal disulfide-bonded peptides involved in root nodule signaling and ii) exploring the functional diversity of A1b for novel bioactive molecules.

RESULTS

Investigating the Mtr genome revealed a remarkable expansion, mainly through tandem duplications, of albumin1 (A1) genes, retaining nearly all of the same canonical structure at both gene and protein levels. Phylogenetic analysis revealed that the ancestral molecule was most probably insecticidal giving rise to, among others, A1b-nodulins. Expression meta-analysis revealed that many A1b coding genes are silent and a wide tissue distribution of the A1 transcripts/peptides within plant organs. Evolutionary rate analyses highlighted branches and sites with positive selection signatures, including two sites shown to be critical for insecticidal activity. Seven peptides were chemically synthesized and folded in vitro, then assayed for their biological activity. Among these, AG41 (aka MtrA1013 isoform, encoded by the orphan TA24778 contig.), showed an unexpectedly high insecticidal activity. The study highlights the unique burst of diversity of A1 peptides within the Medicago genus compared to the other taxa for which full-genomes are available: no A1 member in Lotus, or in red clover to date, while only a few are present in chick pea, soybean or pigeon pea genomes.

CONCLUSION

The expansion of the A1 family in the Medicago genus is reminiscent of the situation described for another disulfide-rich peptide family, the "Nodule-specific Cysteine-Rich" (NCR), discovered within the same species. The oldest insecticidal A1b toxin was described from the Sophorae, dating the birth of this seed-defense function to more than 58 million years, and making this model of plant/insect toxin/receptor (A1b/insect v-ATPase) one of the oldest known.

Acute appendicitis in South Africa: a systematic review

BACKGROUND

Acute appendicitis is one of the most common surgical emergencies in the West. A large body of research is investigating the risk factors for disease and perforation. As South Africa has a social environment, health system structure, and population demography unique from developed nations, the findings may not be generalisable to this setting. A systematic review has not been performed for appendicitis research in South Africa. The objective of this review was to systematically examine the literature on appendicitis in South Africa.

METHOD

Published articles discussing appendicitis in South Africa up to March 2014 were identified using MEDLINE and EBMReviews. Research themes were analysed in the literature. Perforation rates, mortality, negative appendicectomy rates and gender differences were analysed from audits of patients undergoing appendicectomy for acute appendicitis.

RESULTS

Ten audits were included in the quantitative analysis. Some were excluded in the subgroup analyses. Negative appendicectomies occurred at a rate of 17% (580/3 354). Women were more likely to have a negative appendicectomy than men (28% vs. 9%, p < 0.01). The perforation rate for appendicectomy patients was 36% (970/2 688), and mortality rate was 1% (36/2 946). Research efforts focused on investigating differential incidence and outcomes between racial groups within the country.

CONCLUSION

Appendicitis trends in South Africa are consistent with those in developing regions. However, there is lack of research from the private sector. Further research is needed to investigate specific factors which delay care, outcomes and cost analyses for laparoscopic surgery, and the system strengthening of surgical services at district hospitals.

Migration of surgeons ("brain drain"): the University of Cape Town experience

BACKGROUND

The large-scale migration of doctors, including surgeons, from South Africa, has had a major impact on healthcare resources in this country. Although previous studies have suggested that the University of Cape Town (UCT) is of the main institution contributing to this "brain drain", the extent of the problem has not been documented previously. The aim of this study was to investigate where UCT trained surgical registrars go after completing their training.

METHOD

General surgery registrars who trained at UCT and who wrote and passed the FCS final examination between 1992 and 2011 were included in the study. The data for this study were obtained from the examinations office of the Colleges of Medicine of South Africa. The number of registrars writing and passing the final examination, the number of registrars who went overseas, the number of registrars in private practice, and the number of registrars in subspecialist practice, were recorded.

RESULTS

A total of 102 UCT-trained registrars wrote and passed the FCS final examination during the study period. Only 13% of the South African UCT-trained registrars left the country. Only 31% of the registrars who remained in South Africa went into private practice. A large proportion of the UCT-trained registrars (43%) elected to subspecialise.

CONCLUSION

"Brain drain" with respect to UCT-trained surgical registrars was not as extensive as anticipated.

Schistosoma prevalence in appendicitis

BACKGROUND

Schistosomiasis is a waterborne trematode with numerous subtypes affecting different areas of the body. Rob Ferreira Hospital is located in an endemic area for schistosomiasis in the Lowveld region of South Africa. We set out to determine the prevalence of Sch istosoma in appendicitis.

METHODS

From 2009 to 2013, all appendix samples removed in theatre were reviewed. A total of 304 cases were retrieved. Viable ova, calcified ova, or schistosomal granulomas was considered proof of exposure.

RESULTS

Thirty-one out of the 304 cases revealed evidence of schistosomal exposure, equating to 10.2 %.

CONCLUSION

A prevalence of more than 10 % is truly significant seeing as how a delayed diagnosis can lead to serious complications, or how a misdiagnosis can result in unnecessary and often protracted treatment with harmful drugs.

Management of blunt liver trauma in 134 severely injured patients

BACKGROUND

In haemodynamic stable patients without an acute abdomen, nonoperative management (NOM) of blunt liver injuries (BLI) has become the standard of care with a reported success rate of between 80 and 100%. Concern has been expressed about the potential overuse of NOM and the fact that failed NOM is associated with higher mortality rate. The aim of this study was to evaluate factors that might indicate the need for surgical intervention, and to assess the efficacy of NOM.

METHODS

A single centre prospective study between 2008 and 2013 in a level-1 Trauma Centre. One hundred thirty four patients with BLI were diagnosed on CT-scan or at laparotomy. The median ISS was 25 (range 16-34).

RESULTS

Thirty five (26%) patients underwent an early exploratory laparotomy. The indication for surgery was haemodynamic instability in 11 (31%) patients, an acute abdomen in 16 (46%), and 8 (23%) patients had CT findings of intraabdominal injuries, other than the hepatic injury, that required surgical repair. NOM was initiated in 99 (74%) patients, 36 patients had associated intraabdominal solid organ injuries. Seven patients developed liver related complications. Five (5%) patients required a delayed laparotomy (liver related (3), splenic injury (2)). NOM failure was not related to the presence of shock on admission (p=1000), to the grade of liver injury (p=0.790) or associated intraabdominal injuries (p=0.866).

CONCLUSION

Physiologic behaviour or CT findings dictated the need for operative intervention. NOM of BLI has a high success rate (95%). Nonoperative management of BLI should be considered in patients who respond to resuscitation, irrespective of the grade of liver trauma. Associated intraabdominal solid organ injuries do not exclude NOM.

Public attitudes to organ donation among a sample of urban-dwelling South African adults: a 2012 study

BACKGROUND

Published literature suggests that attitudes toward organ donation in South Africa are generally positive. However, there has been a decline in the actual number of transplants taking place annually, which is not consistent with expressed positive attitudes.

OBJECTIVES

Assess the attitudes of a representative sample of the urban-dwelling South African population toward organ donation and how these might affect transplant numbers.

METHODS

A structured questionnaire was utilized to measure attitudes among a study population of 1048 adults in five major metropolitan areas of South Africa. Field work was undertaken by supervised field workers. Written informed consent was obtained from all participants.

RESULTS

Eighty-nine percent (89%) of respondents had heard of organ donation, and 77% indicated that they would accept an organ transplant if necessary. Seventy percent (70%) of respondents specified they would be willing to donate their own organs after death, while 67% expressed willingness to donate a relative's organs after death. Participants were more positive about kidney donation than any other organ.

CONCLUSION

Public attitudes toward organ donation among this population are generally positive. Recommendations include cultural and linguistic sensitivity in educational and advertising campaigns, as well as extensive research into other possible causes of organ shortage.

Should the "in situ" simulation become the new way in Belgium? Experience of an academic hospital

The place of simulation in medical education, particularly in anesthesia, appears to be more and more evident. However, the history of simulation in Belgium showed that the associated costs remain a barrier. The use of 'in situ' simulation, defined as the practice of simulation in the usual workplace, could solve the problem of providing access to this educational tool. Indeed, it allows reducing equipment and manpower costs: the needed equipment comes from the hospital, and supervision and organization are provided by staff members. It also provides access to simulation for a larger number of individuals on site. The environment is more realistic because the participants operate in their usual workplace, with their customary equipment and team. Furthermore, 'in situ' simulation allows participation of the paramedical staff. This allows developing skills related to teamwork and communication. Despite those numerous advantages, several difficulties persist. The associated logistic and organizational constraints can be cumbersome.

Slow early graft function: a neglected entity after renal transplantation

BACKGROUND

After renal transplantation, early graft function (EGF) can be divided into delayed graft function (DGF), slow graft function (SGF) and immediate graft function (IGF). DGF is well documented. However, when evaluating the long-term significance of early function, the literature shows conflicting definitions and inconsistent results. In addition, SGF, a new entity separate to DGF and IGF, is a recent and poorly understood development.

AIM

To investigate the risk factors for and the impact of poor EGF (PEGF) on long-term outcome.

METHODS

This retrospective study reviewed the records of local adult patients who underwent renal transplantation at the Groote Schuur Hospital (Cape Town, South Africa) between 2004 and 2008. EGF was divided according to day 5 serum creatinine into IGF (serum creatinine <150 µmol/l), SGF (serum creatinine >150 but <450 µmol/l) and DGF (serum creatinine >450 µmol/l or dialysis in the first week). DGF and SGF together comprised PEGF, with IGF alone representing good EGF (GEGF).

RESULTS

A total of 121 patients (77 men, 44 women; mean age 39 years, range 14-67) were included in the study. Eighteen were excluded due to nephrectomy (n = 8), death (n = 6) or loss to follow-up (n = 4) within the first year. Analysis of cadaveric donors showed no significant risk factors for PEGF with the exception of cold ischaemic time, which differed significantly between the GEGF and PEGF groups, with means of 12 and 16 h, respectively (p = 0.013). Considering both living and cadaveric grafts, the 1-year estimated glomerular filtration rate (eGFR) was significantly different between IGF and DGF (p = 0.038) as well as between IGF and SGF (p = 0.028), with no significant difference between SGF and DGF (p > 0.05). A comparison of the PEGF and GEGF groups yielded significantly different 1-year eGFR values (60 and 50 ml/min, respectively; p = 0.07), with PEGF also associated with a longer hospital stay (20 vs. 14 days; p = 0.00005). Acute rejection was independently associated with a lower 1-year eGFR (p = 0.028), but in the absence of rejection, GEGF and PEGF remained significantly different with regards to 1-year eGFR (p = 0.024).

CONCLUSIONS

SGF is not related to IGF but rather to DGF and should thus be regarded as a form of PEGF as opposed to GEGF. PEGF has a worse long-term outcome, and this indicates the need for increased efforts in its prevention and greater attention to its management.

Deceased donor organ transplantation: A single center experience from Cape Town, South Africa

Deceased donor kidney transplantation have been in place for more than ten years at Groote Schuur Hospital in Cape Town, South Africa. This retrospective review between 1995 and 2005 reports the experience with 824 deceased donor referrals. Race breakdown showed that 321 donors were black, 154 white, 318 mixed race and 30 unrecorded. Consent remains a major problem in South Africa and we were unable to obtain consent in 43% of our patients. Only 20% of donors had natural causes of death – the majority died because of trauma/unnatural circumstances. For this reason the average age of our donors are 26 years. A and O blood group donors were the most prevalent with A blood group patients making up 38% and O blood group 39% of the donor population.

Pregnancy following liver transplantation during childhood and adolescence

More than 80% of pediatric transplant recipients will survive to reach adulthood, and many will consider having children. We report on outcomes and management of five pregnancies in four women undergoing orthotopic liver transplantation during childhood or adolescence and followed up at our Transplant Center. A retrospective clinical folder audit was performed. Mean age at transplantation was 13.3 ± 3.4 yr (range, 10-18 yr). Mean interval between transplantation and pregnancy was 15.4 ± 4.9 yr (range, 10-22 yr). Mean maternal age at conception was 28 ± 3.5 yr (range, 23-32 yr). Mean gestational age was 36.6 ± 1.7 wk. Mean birth weight was 2672 ± 249 g. Immunosuppression was cyclosporin based in three women and tacrolimus based in one woman. Pregnancy complications necessitating the induction of labor included fetal distress and rising maternal liver enzymes in two women, cholestasis of pregnancy and impaired renal graft function in one woman, fetal distress and preeclampsia in one woman. Modes of delivery were normal vaginal delivery in three women and cesarean section in one woman. No maternal or fetal deaths and no congenital malformations occurred. No episodes of rejection occurred during pregnancy. Two women experienced acute cellular rejection requiring an increase in baseline immunosuppression in the first year, following delivery. No graft losses occurred during a mean follow-up of 44 ± 17.9 months post-delivery. With careful management, pregnancy post-liver transplantation can have a successful outcome.

A student surgical society - the Cape Town experience

The UCT Surgical Society, Africa's only student surgical society, is a student-managed academic society that promotes undergraduate interest in the field of surgery at the University of Cape Town. With over 700 members in 2009, it is one of the largest student surgical societies in the world. This article describes the origins, aims and objectives of the Society, and outlines a framework that students anywhere may use to create their own academic interest societies.

Effect of liver regeneration on the pharmacokinetics of immunosuppressive drugs

In liver transplantation the graft has been known to undergo regeneration, which is associated with down-regulation of the cytochrome P450 system. The latter is involved in the metabolism of several immunosuppressive drugs. The aim of this study was to investigate the effect of liver regeneration on the pharmacokinetics (PK) of cyclosporine, rapamycin, and tacrolimus. Rats were subjected to either partial hepatectomy (PH) or sham operation (SH). Cyclosporine, rapamycin, and tacrolimus PK studies were performed at 0, 24, and 96 hours postoperatively. The areas under the curve (AUC), trough levels, and maximum concentrations (Cmax) for cyclosporine and tacrolimus were numerically higher in the animals subjected to PH. The PK studies of rapamycin were not affected by PH. These studies indicated that cyclosporine and tacrolimus metabolism may be inhibited during liver regeneration.

Risk of blood splashes to the eye during surgery

BACKGROUND

With the advent of a new infectious era involving the HIV and hepatitis B and C viruses, concern has arisen about transmission of these viruses through ocular blood splashes during surgery. The purpose of the study was to determine the risk of ocular blood splashes to surgeons and their assistants during surgery.

METHOD

Surgeons and assistants in several surgical disciplines were requested to wear facemasks with a transparent plastic visor. The visors were collected postoperatively and inspected for macroscopic and microscopic blood splashes.

RESULTS

Fifty-nine per cent of the surgeons and assistants refused to wear facemasks with a visor. The incidence of blood splashes in those who participated was 45%. There was a trend for blood splashes to be more common during major surgery and during elective surgery. Surgeons and assistants were subject to similar risk.

CONCLUSION

This study confirms the significant risk of ocular blood splashes during surgery, while also suggesting that both surgeons and assistants lack appreciation of the risk.

Ischaemic preconditioning of the liver before transplantation

PURPOSE

Assessment of the effect of a short ischaemic time prior to liver transplantation on the liver graft.

METHODS

White X Landrace pigs (N=10) were subjected to liver transplantation. Before being removed from the donor animal, the livers were randomised into two groups: group 1--pre-procurement ischaemia (15 minutes' temporary arrest of portal venous and hepatic arterial inflow to the liver, followed by reperfusion of these vessels for a period of 15 minutes); group 2--no prior inflow occlusion (control group). In group 1 a spleno-jugular bypass was established to prevent venous congestion, portal venous hypertension, intestinal oedema and bacterial translocation. The livers were perfused with Eurocollins solution (4 degrees C), after which they were stored on ice for a period of 3 hours' cold ischaemic time. Hepatocellular injury was assessed according to liver cell function tests (aspartate aminotransferase, AST), biochemical indicators of reperfusion injury (malondialdehyde) and histopathology.

RESULTS

There was a significant rise of AST in both groups 1 hour after transplantation (from 51 +/- 27 IU/l to 357 +/- 152 IU/l in group 1 and from 29 +/- 10 IU/l to 359 +/- 198 IU/l in group 2). AST levels were marginally lower in group 1 at 2 and 4 hours after transplantation. There was also a rise in malondialdehyde levels in both groups at 5, 20, 40 and 60 minutes after transplantation. Levels of malondialdehyde were lower in the primed group at 5, 20 and 40 minutes, while the levels at 60 minutes after transplantation were comparable. Histological changes, as measured by vacuolisation, neutrophil infiltration and hepatic cell necrosis, were less in livers transplanted after ischaemic preconditioning, although the difference was not significant.

CONCLUSIONS

Ischaemic preconditioning of the donor liver seems to decrease hepatocellular damage, reperfusion injury and histological changes in the liver after transplantation. Further studies with larger numbers are indicated.

Targeted radiopharmaceutical therapy for advanced lung cancer: Phase I trial of rhenium Re188 somatostatin analogue P2045

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Background: Both small cell (SCLC) and non-small cell lung cancer (NSCLC) overexpress somatostatin receptors (SSTR). P2045 peptide is an 11-amino acid somatostatin analogue that binds with high affinity to SSTR. The analogue can be labeled with Tc-99m to gauge receptor prevalence, or with Re-188 for 2.1MeV beta radiotherapy. To evaluate the safety of this approach a phase I dose-escalation study of Re-188 P2045 in SSTR positive lung cancer was performed. Methods: Patients (pts) were required to have progressive advanced lung cancer, PS 0–1, and normal organ function. There were no limitations on the number of prior therapies. Tumor SSTR was detected with Tc-99m P2045. If positive, treatment with escalating doses of Re-188 P2045 was instituted. Three doses were evaluated, 30 mCi/m2, 60 mCi/m2 and 90 mCi/m2. A single dose of Re-188 P2045 was allowed. Dose limiting toxicity was defined as ≥ grade 3 non-hematologic toxicity, grade 4 hematologic toxicity or projected renal radiation dose of >20 Gy. Results: 15 pts entered, 7 M, 8 F, median age 61y, 9-PS0, 6 PS1. 13 NSCLC, 2 SCLC. 14 pts had ≥ 2 prior chemotherapy regimens. 1 pt refused standard therapy. All pts were imaged with Tc-99m P2045, 8 pts received Re-188 P2045. The 7 pts who did not proceed to Re-188 P2045 were due to rapid progression (n=2) non-uptake of Tc 99m P2045 (n=2) or projected renal radiation dose above the 20 Gy limit (n=3). All pts treated with Re-188 P2045 (4 at 30 mCi/m2, 3 at 60 mCi/m2 and 1 at 90 mCi/m2) had NSCLC. The major toxicity was grade 1 or 2 lymphopenia. No dose limiting toxicities were seen. All tumors imaged by Tc-99m had uptake of Re- 188. The trial was halted at the 90 mCi/m2 level when 3 pts had projected renal radiation doses above 20Gy. No responses were seen. 5 of the 8 pts (62.5%, 95% CI: 24%, 91%) had stable disease at 8 weeks, all of whom entered with progressive disease.. Median overall survival was 11.5 mo. Conclusions: 1) Re-188 P2045 was well-tolerated. 2) Tc-99m P2045 imaging allows identification of pts who may benefit from Re-188 P2045. 3) While responses were not seen, survival for these heavily pretreated pts is encouraging. 4) Further exploration of this approach utilizing amino acid infusion to ameliorate potential renal toxicity is warranted.

No significant financial relationships to disclose.

Biochemical and immunohistochemical characterisation of mucins in 8 cases of colonic disease--a pilot study

OBJECTIVES

To characterise mucins in cancer of the colon and compare these with controls using stringent biochemical measures to avoid endogenous proteolysis.

DESIGN

Crude mucus scrapings were collected from 12 specimens obtained by colectomy. Specimens from 3 traumatic colectomies and 1 sigmoid volvulus were used as controls, and compared with 6 specimens from colons resected for adenocarcinoma and 2 irradiated colons.

SUBJECTS

The median age of the 4 female patients was 76 years (range 49 - 82 years), and of the 8 male patients 46.5 years (range 16 - 74 years).

RESULTS AND CONCLUSIONS

The crude mucus scrapings in the 9 specimens ranged in weight from 353 mg to 7 697 mg (median 4 928 mg). The median of purified mucin in the 9 specimens was 0.72 microg/mg wet weight of scraped material. Eight samples gave non-extractable pellet material, and were treated with DTT to reduce disulphide bonds for further analysis. One of these 8 pellets was resistant to reduction and had to be digested with papain before analysis. Only 5 of these pellets had mucin. Gel filtration and SDS-PAGE (sodium dodecyl sulphate polyacrylamide gel electrophoresis) analysis revealed different populations of mucin based on size and extent of degradation. Western blotting and immunohistochemical analysis confirmed the presence of MUC2 in all samples, MUC5AC in 2 and MUC5B in 5 diseased specimens. Immunohistochemical analysis showed that there was no MUC1 in the normal specimens, MUC1 apoprotein (MUC1 core) in 2 cancer specimens and MUC1 in 1 cancer specimen. Histochemical analysis showed that normal tissue expressed neutral and acidic mucins and diseased specimens predominantly expressed acidic mucins. The electrophoretic behaviour of MUC2 in sigmoid volvulus was different from that in cancer of the colon.

Hierarchy of metabolic compounds based on their synthesising capacity

The concept of scopes is applied to analyse large metabolic networks. Scopes are defined as sets of metabolites that can be synthesised by a metabolic network when it is provided with given seeds (Sets of initial metabolic compounds). Thus, scopes represent synthesising capacities of the seeds in the network. A hierarchy is discussed in the sense that compounds, which are part of the scope of another compound, possess scopes themselves that are subsets of the former scope. This hierarchy is analysed by means of a directed acyclic graph. Using a simple chemical model, it is found that this hierarchy contains specific structures that can, to a large extent, be explained by the chemical composition of the participating compounds. In this way, it represents a new kind of map of metabolic networks, arranging the metabolic compounds according to their chemical capacity.

Evolutionary changes of metabolic networks and their biosynthetic capacities

The metabolic networks of different species show a large variety in their structural design. In this work, the evolution of functional properties of metabolism in relation with metabolic network structure is investigated. The metabolism of ancestral species is inferred from the metabolism of contemporary species using a Bayesian network model for metabolism evolution. Subsequently, these networks are analysed with the recently developed method of network expansion. This method allows for a structural analysis of metabolic networks as well as a quantification of network functions in terms of their synthesising capacities when they are provided with certain external resources. The evolutionary dynamics of one particular network function: the metabolic expansion of glucose is investigated.