HIV associated malignancies presenting as acute pancreatitis: a case series

BACKGROUND

Acute pancreatitis (AP) may be the presenting symptom in a small percentage of patients harbouring pancreatic or extra pancreatic tumours. This case series aims to describe the pathological spectrum of tumours detected in two AP cohorts from a high HIV-endemic region.

METHODS

Prospectively collected databases of patients admitted with AP over two periods 2001 to 2010 and 2013 to 2015, were retrospectively evaluated to detect those with pancreatic and extra-pancreatic tumours. The diagnosis of AP was by standard criteria. HIV infection and CD4 counts were routinely tested for in the latter period and only tested on clinical grounds in the initial period. CT scan was performed when there was diagnostic doubt, predicted severe disease, and failure to improve clinically after one week. Demographic, clinical, investigative, and pathology details were collected and presented.

RESULTS

HIV-positive patients admitted with AP were 106 (17%) of 628 in the first period and 90 (38%) of 238 of the second period. No tumours were diagnosed in the HIV-negative patients. Seven of the HIV-positive patients had tumours diagnosed at endoscopy, CT scan, and endoscopic retrograde cholangiography. Of the seven HIV-positive patients with tumours, two patients had a CD4 count above 200. There were four patients with lymphoma involving the pancreatic head, three having associated cholestasis, and three patients with Kaposi's Sarcoma. One Kaposi's sarcoma patient died three months after presentation. One patient with lymphoma died on day 14 and another two months after initial presentation, and the remaining four patients were referred to oncology.

CONCLUSION

Despite their rarity (< 4%), when HIV-positive patients with low CD4 count and cholestasis present with AP,tumours should be suspected and evaluated by cross sectional imaging and endoscopic ultrasound.

HIV associated malignancies presenting as acute pancreatitis: a case series

BACKGROUND

Acute pancreatitis (AP) may be the presenting symptom in a small percentage of patients harbouring pancreatic or extra pancreatic tumours. This case series aims to describe the pathological spectrum of tumours detected in two AP cohorts from a high HIV-endemic region.

METHODS

Prospectively collected databases of patients admitted with AP over two periods 2001 to 2010 and 2013 to 2015, were retrospectively evaluated to detect those with pancreatic and extra-pancreatic tumours. The diagnosis of AP was by standard criteria. HIV infection and CD4 counts were routinely tested for in the latter period and only tested on clinical grounds in the initial period. CT scan was performed when there was diagnostic doubt, predicted severe disease, and failure to improve clinically after one week. Demographic, clinical, investigative, and pathology details were collected and presented.

RESULTS

HIV-positive patients admitted with AP were 106 (17%) of 628 in the first period and 90 (38%) of 238 of the second period. No tumours were diagnosed in the HIV-negative patients. Seven of the HIV-positive patients had tumours diagnosed at endoscopy, CT scan, and endoscopic retrograde cholangiography. Of the seven HIV-positive patients with tumours, two patients had a CD4 count above 200. There were four patients with lymphoma involving the pancreatic head, three having associated cholestasis, and three patients with Kaposi's Sarcoma. One Kaposi's sarcoma patient died three months after presentation. One patient with lymphoma died on day 14 and another two months after initial presentation, and the remaining four patients were referred to oncology.

CONCLUSION

Despite their rarity (< 4%), when HIV-positive patients with low CD4 count and cholestasis present with AP, tumours should be suspected and evaluated by cross sectional imaging and endoscopic ultrasound.

The utility of the bedside index of severity in acute pancreatitis at prognosticating adverse outcomes

BACKGROUND

Identification of at-risk patients with acute pancreatitis (AP) early on in the course of hospital admission remains a challenge. Early identification of these patients can facilitate early referral to tertiary hospitals with skilled multidisciplinary teams (MDTs) and high-dependency health care facilities. This study retrospectively reviewed the ability of the bedside index of severity in acute pancreatitis (BISAP) score and other biochemical markers to predict organ failure and mortality in acute pancreatitis.

METHODS

All patients presenting to Grey's Hospital with AP between 2012 and 2020 were included in the study. The BISAP score and other biomarkers were evaluated at presentation in predicting organ failure (≥ 48 hours duration) and mortality.

RESULTS

A total of 235 patients were included in the study. A total of 144 (61%) were male and 91 (39%) were female. Alcohol (81%) and gallstones (69%) were the commonest aetiological factors amongst males and females respectively. A total of 42 (29%) males and 10 (11%) females developed organ failure during their hospital stay. The mortality rate was 11.8% for males, 6.59% for females, with an overall mortality of 9.8%. A BISAP score of 2 had a sensitivity of 87.98% and specificity of 59.62% at predicting organ failure (positive predictive value [PPV] = 88.46%, negative predictive value [NPV] = 58.49%, 95% confidence interval [CI], p = 0.001). A BISAP score of 3 and above had a sensitivity of 98.11% and specificity of 69.57% at predicting mortality (PPV = 96.74%, NPV = 80%, 95% CI, p = 0.001). A multivariate analysis of biomarkers bicarbonate, base excess, lactate, urea and creatinine either failed to reach statistical significance or had specificity that is too low to prognosticate organ failure and mortality.

CONCLUSION

The BISAP score has limitations at predicting organ failure, but it is a reliable tool for predicting mortality in AP. Due to its simplicity of use, it should be used in resource-constrained settings to triage at-risk patients in smaller hospitals, for early referral to tertiary hospitals.

Spectrum and surgical outcomes of gastrointestinal stromal tumours

BACKGROUND

Surgery and imatinib are the mainstays of the management of gastrointestinal stromal tumours (GIST). This study aimed to analyse the outcomes in the management of GIST utilising surgery and imatinib.

METHODS

Progression-free survival (PFS) and overall survival (OS) were analysed in relation to imatinib therapy, location of tumour, resection margins, type and extent of surgery. Imatinib was administered in the neoadjuvant (maximum 12 months) and adjuvant setting (minimum 36 months) and until disease progression or drug intolerance. Disease response was assessed with the Choi criteria. Survival analysis included calculation of PFS, OS and Kaplan-Meier curves.

RESULTS

Sixty-two patients were reviewed and 56 had surgical resection. The median age (range) was 58.5 (8-95) years. The median PFS and OS (IQR) was 24.0 (0-52.0) and 41.0 (15.0-74.0) months, respectively. Thirty-nine (70%) patients were treated with imatinib, with 21 of these in a neoadjuvant setting. In the patients undergoing surgery, surgical margins were R0, R1 and R2 in 41 (75%), eight (15%) and six (11%) respectively. There was an insignificant difference in the overall survival in these three groups. For those having liver metastasectomy and multivisceral resection, the PFS and OS were 32.5 (17.5-60.3) and 28.5 (5.75-49.8) (p = 0.008), and 96.0 (58.5-116) and 80 (50.5-92.3) months (p = 0.033), respectively.

CONCLUSION

Whilst the numbers were small, certain trends were observed. Surgery in combination with imatinib offers survival benefit in patients undergoing R0, R1, R2, liver metastases and multivisceral resections.

HIV specific CD8+ TRM-like cells in tonsils express exhaustive signatures in the absence of natural HIV control

Lymphoid tissues are an important HIV reservoir site that persists in the face of antiretroviral therapy and natural immunity. Targeting these reservoirs by harnessing the antiviral activity of local tissue-resident memory (TRM) CD8+ T-cells is of great interest, but limited data exist on TRM-like cells within lymph nodes of people living with HIV (PLWH). Here, we studied tonsil CD8+ T-cells obtained from PLWH and uninfected controls from South Africa. We show that these cells are preferentially located outside the germinal centers (GCs), the main reservoir site for HIV, and display a low cytolytic and a transcriptionally TRM-like profile distinct from blood CD8+ T-cells. In PLWH, CD8+ TRM-like cells are expanded and adopt a more cytolytic, activated, and exhausted phenotype not reversed by antiretroviral therapy (ART). This phenotype was enhanced in HIV-specific CD8+ T-cells from tonsils compared to matched blood suggesting a higher antigen burden in tonsils. Single-cell transcriptional and clonotype resolution showed that these HIV-specific CD8+ T-cells in the tonsils express heterogeneous signatures of T-cell activation, clonal expansion, and exhaustion ex-vivo. Interestingly, this signature was absent in a natural HIV controller, who expressed lower PD-1 and CXCR5 levels and reduced transcriptional evidence of T-cell activation, exhaustion, and cytolytic activity. These data provide important insights into lymphoid tissue-derived HIV-specific CD8+ TRM-like phenotypes in settings of HIV remission and highlight their potential for immunotherapy and targeting of the HIV reservoirs.

Bone mineral concentration predicted by dual energy X-ray absorptiometry and its relationship with lamb eating quality

Lumbar bone mineral concentration, as predicted by dual energy x-ray absorptiometry (DEXA), may reflect changes in lamb maturity and eating quality. New season (n = 60) and old season (n = 60) lambs were slaughtered and DEXA scanned at a commercial abattoir across 2 kill groups. The second lumbar vertebra was isolated from the spine for determination of calcium, phosphorus, and magnesium concentration (mg/g). The loin and rack cuts were collected for consumer sensory grilling and roasting analyses. Mineral concentration was significantly higher in old season lambs within kill group 1 (P < 0.05). DEXA was a positive predictor of phosphorus and calcium concentration, but only when DEXA lean % (P < 0.05) was included in the model. Calcium and phosphorus were significant positive predictors of overall liking scores (P < 0.05), but only for the rack roast. These effects became insignificant when DEXA lean % was included. These results suggest that DEXA values likely reflect changes in both DEXA lean % and bone minerals, and that DEXA lean % was the driver of eating quality, rather than maturity.

Irreversible depletion of intestinal CD4+ T cells is associated with T cell activation during chronic HIV infection

HIV infection in the human gastrointestinal (GI) tract is thought to be central to HIV progression, but knowledge of this interaction is primarily limited to cohorts within Westernized countries. Here, we present a large cohort recruited from high HIV endemic areas in South Africa and found that people living with HIV (PLWH) presented at a younger age for investigation in the GI clinic. We identified severe CD4⁺ T cell depletion in the GI tract, which was greater in the small intestine than in the large intestine and not correlated with years on antiretroviral treatment (ART) or plasma viremia. HIV-p24 staining showed persistent viral expression, particularly in the colon, despite full suppression of plasma viremia. Quantification of mucosal antiretroviral (ARV) drugs revealed no differences in drug penetration between the duodenum and colon. Plasma markers of gut barrier breakdown and immune activation were elevated irrespective of HIV, but peripheral T cell activation was inversely correlated with loss of gut CD4⁺ T cells in PLWH alone. T cell activation is a strong predictor of HIV progression and independent of plasma viral load, implying that the irreversible loss of GI CD4⁺ T cells is a key event in the HIV pathogenesis of PLWH in South Africa, yet the underlying mechanisms remain unknown.

HIV infection drives interferon signaling within intestinal SARS-CoV-2 target cells

SARS-CoV-2 infects epithelial cells of the human gastrointestinal (GI) tract and causes related symptoms. HIV infection impairs gut homeostasis and is associated with an increased risk of COVID-19 fatality. To investigate the potential link between these observations, we analyzed single-cell transcriptional profiles and SARS-CoV-2 entry receptor expression across lymphoid and mucosal human tissue from chronically HIV-infected individuals and uninfected controls. Absorptive gut enterocytes displayed the highest coexpression of SARS-CoV-2 receptors ACE2, TMPRSS2, and TMPRSS4, of which ACE2 expression was associated with canonical interferon response and antiviral genes. Chronic treated HIV infection was associated with a clear antiviral response in gut enterocytes and, unexpectedly, with a substantial reduction of ACE2 and TMPRSS2 target cells. Gut tissue from SARS-CoV-2–infected individuals, however, showed abundant SARS-CoV-2 nucleocapsid protein in both the large and small intestine, including an HIV-coinfected individual. Thus, upregulation of antiviral response genes and downregulation of ACE2 and TMPRSS2 in the GI tract of HIV-infected individuals does not prevent SARS-CoV-2 infection in this compartment. The impact of these HIV-associated intestinal mucosal changes on SARS-CoV-2 infection dynamics, disease severity, and vaccine responses remains unclear and requires further investigation.

Capturing lean distribution in lamb carcases is of more value to the processor than the breeder

With an increased implementation of chain speed measures of lean weight in lamb processing plants there is the potential for increased feedback of measures for carcase composition to the breeder. The following studies used computed tomography scans of 3167 Merino and Merino cross lamb carcases to determine the importance of capturing variation in carcase, fore, saddle and hind section lean to the processor and the breeder. Sectional measures of lean weight will provide processors with improved precision around the decision making associated with carcase processing and endpoint usage. Genetic correlations between lean (adjusted for carcase weight) within carcase sections ranged from 0.47 to 0.63. Whilst the correlations are moderate, current differences in the value of lean across the carcase does not make it viable for sheep breeders to target disproportional gains in lean across carcase sections. Instead, sheep breeders should continue to target overall carcase lean as part of their breeding objective.

Unbiased Profiling Reveals Compartmentalization of Unconventional T-Cells Within the Intestinal Mucosa Irrespective of HIV Infection

The intestinal mucosa is enriched for unconventional T-cells, including mucosal associated invariant T-cells (MAIT), invariant natural killer T-cells (iNKT) and γδ T-cells. These cells are activated by bacterial metabolites, lipid antigens and cytokines, and are important for intestinal barrier integrity. The loss of gut homeostasis observed in HIV infection is central to disease pathogenesis, and studies have highlighted impairment of particular unconventional T-cell subsets within a specific gut compartment. However, although the small and large intestine are distinct niches, the overall impact of HIV on unconventional T-cells across the gut mucosal has not been well-studied. We hypothesized that compartment specific differences in the unconventional T-cell repertoire would exist between the small and large intestine, due to increasing bacterial loads and microbial diversity; and that the impact of HIV infection might differ depending on the compartment examined. We used mass cytometry, flow cytometry and unbiased T-cell receptor profiling to quantify unconventional T-cells in blood and tissue from the small (duodenum) and large (colon) intestine in HIV infected and uninfected participants undergoing examination for a range of intestinal conditions. Overall, we find distinct compartmentalisation of T-cells between blood, duodenum and colon, with iNKT cells significantly enriched in the duodenum and δ-1 expressing γδ T-cells in the colon. In addition, we observe greater clonal expansion of conventional TCRs in the duodenum, suggestive of stronger adaptive immunity in this compartment. Conversely, we find evidence of an expanded unconventional TCR repertoire in the colon, which contained far more overlapping “donor unrestricted” sequences than the duodenum. Twelve of these TCRs were highly “MAIT-like” and 3 were unique to the colon, suggesting an enrichment of donor unrestricted T-cells (DURTs) in this compartment. Unexpectedly, however, no significant impact of HIV infection on any of the unconventional T-cell subsets measured was observed in either mucosal site in terms of frequency or TCR repertoire. Further studies are required to investigate the importance of these unconventional T-cell subsets to intestinal homeostasis within the different gut compartments and determine if they are functionally impaired during HIV infection.

Knowledge and attitude of patients undergoing lower extremity amputation at RK Khan Hospital, Chatsworth

BACKGROUND

Amputation is one of the oldest and most commonly performed surgical procedures.

OBJECTIVE

To review the knowledge and attitude of patients undergoing lower extremity amputations and describe the associated causative factors.

METHODOLOGY

A questionnaire-based prospective study assessing patients either preoperatively or immediately postoperatively regarding their knowledge and attitudes toward lower extremity amputation was conducted between November 2016 and April 2017. Extracted data was captured into an Excel spreadsheet and imported into SPSS for statistical analysis.

RESULTS

Sixty-three amputations were performed with males accounting for 56% of the study population. The majority were in the age group of 61-70 years (33%). The commonest indication for amputation was complication of diabetes mellitus or diabetes foot sepsis (65%). Below-knee amputation (BKA) was the most frequently performed procedure and accounted for 56% of all amputations. Seventy per cent of the participants had formal education and 60% knew that their condition could lead to an amputation, but only approximately 10% visited the foot clinic before their major amputation despite the service being available at RK Khan Hospital. Smoking was the commonest habit associated with amputation.

CONCLUSION

There is a gradual temporal increase in the frequency of resected papillary cancer over a 16 year period while follicular has remained static. These changes may be attributable to better salt iodination.

Inflorescence evolution in Santalales: integrating morphological characters and molecular phylogenetics

PREMISE OF THE STUDY

The sandalwood order (Santalales) includes members that present a diverse array of inflorescence types, some of which are unique among angiosperms. This diversity presents not only interpretational challenges but also opportunities to test fundamental concepts in plant morphology. Here we used modern phylogenetic approaches to address the evolution of inflorescences in the sandalwood order.

METHODS

Phylogenetic analyses of two nuclear and three chloroplast genes were conducted on representatives of 146 of the 163 genera in the order. A matrix was constructed that scored nine characters dealing with inflorescences. One character, "trios", that encompasses any grouping of three flowers (i.e., both dichasia and triads) was optimized on samples of the posterior distribution of trees from the Bayesian analysis using BayesTraits. Three nodes were examined: the most recent common ancestors of (A) all ingroup members, (B) Loranthaceae, and (C) Opiliaceae, Santalaceae s.l., and Viscaceae.

KEY RESULTS

The phylogenetic analysis resulted in many fully resolved nodes across Santalales with strong support for 18 clades previously named as families. The trios character was not supported for nodes A and C, whereas it was supported for node B where this partial inflorescence type is best described as a triad.

CONCLUSIONS

Essentially every major inflorescence type can be found in Santalales; however, the dichasium, a type of partial inflorescence, is rarely seen and is not plesiomorphic for the order. In the family Erythropalaceae, inflorescences are mostly in small, axillary fascicles or cymes. Successive families show both cymose and racemose types and compound systems (e.g., thyrses). Inflorescences in Amphorogynaceae and Viscaceae are not dichasial and in general are difficult to compare to "standard" inflorescences.

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

BACKGROUND

Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world.

METHODS

This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231.

FINDINGS

Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p<0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05-2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p<0·001).

INTERPRETATION

Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication.

FUNDING

DFID-MRC-Wellcome Trust Joint Global Health Trial Development Grant, National Institute of Health Research Global Health Research Unit Grant.

Outcomes in laparoscopic cholecystectomy in a resource constrained environment

BACKGROUND

Laparoscopic cholecystectomy (LC) is a common surgical procedure performed for symptomatic gallstones. There is a trend towards early cholecystectomy for patients with acute cholecystitis who present timeously. Local inflammation has been identified as a risk factor for bile duct injuries. This study sought to assess the outcomes of LC in patients managed within a resource constrained environment where late presentation is common.

METHOD

We performed a retrospective analysis of laparoscopic cholecystectomy performed from January 2010 to June 2011. The mode of presentation, co-morbidities, timing of cholecystectomy and complications were analysed.

RESULTS

One hundred and sixty seven patients were evaluated. The median age was 43 years with range (17-78) years and 93% were female and 7% male. There were 44%, 23%, 20% and 13% who presented with biliary colic, acute pancreatitis, acute cholecystitis and obstructive jaundice respectively. Nine (5.4%) patients required conversion to an open cholecystectomy. Complications occurred in 16.2% and bile duct injuries and bile leaks in 1.2% and 1.8% respectively. One patient died.

CONCLUSION

Most patients had a delayed laparoscopic cholecystectomy. There was no difference in outcomes for the different presentations and the complications are similar to other reports.

Realization of Vertically Aligned, Ultrahigh Aspect Ratio InAsSb Nanowires on Graphite

The monolithic integration of InAs(1-x)Sb(x) semiconductor nanowires on graphitic substrates holds enormous promise for cost-effective, high-performance, and flexible devices in optoelectronics and high-speed electronics. However, the growth of InAs(1-x)Sb(x) nanowires with high aspect ratio essential for device applications is extremely challenging due to Sb-induced suppression of axial growth and enhancement in radial growth. We report the realization of high quality, vertically aligned, nontapered and ultrahigh aspect ratio InAs(1-x)Sb(x) nanowires with Sb composition (xSb(%)) up to ∼12% grown by indium-droplet assisted molecular beam epitaxy on graphite substrate. Low temperature photoluminescence measurements show that the InAs(1-x)Sb(x) nanowires exhibit bright band-to-band related emission with a distinct redshift as a function of Sb composition providing further confirmation of successful Sb incorporation in as-grown nanowires. This study reveals that the graphite substrate is a more favorable platform for InAs(1-x)Sb(x) nanowires that could lead to hybrid heterostructures possessing potential device applications in optoelectronics.

Creating a charter of collaboration for international university partnerships: the Elmina Declaration for Human Resources for Health

The potential of international academic partnerships to build global capacity is critical in efforts to improve health in poorer countries. Academic collaborations, however, are challenged by distance, communication issues, cultural differences, and historical context. The Collaborative Health Alliance for Reshaping Training, Education, and Research project (funded by the Bill and Melinda Gates Foundation and implemented through academic medicine and public health and governmental institutions in Michigan and Ghana) took a prospective approach to address these issues. The project had four objectives: to create a "charter for collaboration" (CFC), to improve data-driven policy making, to enhance health care provider education, and to increase research capacity. The goal of the CFC was to establish principles to guide the course of the technical work. All participants participated at an initial conference in Elmina, Ghana. Nine months later, the CFC had been revised and adopted. A qualitative investigation of the CFC's effects identified three themes: the CFC's unique value, the influence of the process of creating the CFC on patterns of communication, and the creation of a context for research and collaboration. Creating the CFC established a context in which implementing technical interventions became an opportunity for dialogue and developing a mutually beneficial partnership. To increase the likelihood that research results would be translated into policy reforms, the CFC made explicit the opportunities, potential problems, and institutional barriers to be overcome. The process of creating a CFC and the resulting document define a new standard in academic and governmental partnerships.

Differentiating transpiration from evaporation in seasonal agricultural wetlands and the link to advective fluxes in the root zone

The current state of science and engineering related to analyzing wetlands overlooks the importance of transpiration and risks data misinterpretation. In response, we developed hydrologic and mass budgets for agricultural wetlands using electrical conductivity (EC) as a natural conservative tracer. We developed simple differential equations that quantify evaporation and transpiration rates using flow rates and tracer concentrations at wetland inflows and outflows. We used two ideal reactor model solutions, a continuous flow stirred tank reactor (CFSTR) and a plug flow reactor (PFR), to bracket real non-ideal systems. From those models, estimated transpiration ranged from 55% (CFSTR) to 74% (PFR) of total evapotranspiration (ET) rates, consistent with published values using standard methods and direct measurements. The PFR model more appropriately represents these non-ideal agricultural wetlands in which check ponds are in series. Using a flux model, we also developed an equation delineating the root zone depth at which diffusive dominated fluxes transition to advective dominated fluxes. This relationship is similar to the Peclet number that identifies the dominance of advective or diffusive fluxes in surface and groundwater transport. Using diffusion coefficients for inorganic mercury (Hg) and methylmercury (MeHg) we calculated that during high ET periods typical of summer, advective fluxes dominate root zone transport except in the top millimeters below the sediment-water interface. The transition depth has diel and seasonal trends, tracking those of ET. Neglecting this pathway has profound implications: misallocating loads along different hydrologic pathways; misinterpreting seasonal and diel water quality trends; confounding Fick's First Law calculations when determining diffusion fluxes using pore water concentration data; and misinterpreting biogeochemical mechanisms affecting dissolved constituent cycling in the root zone. In addition, our understanding of internal root zone cycling of Hg and other dissolved constituents, benthic fluxes, and biological irrigation may be greatly affected.

Methotrexate in combination with infliximab is no more effective than infliximab alone in patients with Crohn's disease

BACKGROUND & AIMS

Methotrexate and infliximab are effective therapies for Crohn's disease (CD). In the combination of maintenance methotrexate-infliximab trial, we evaluated the potential superiority of combination therapy over infliximab alone.

METHODS

In a 50-week, double-blind, placebo-controlled trial, we compared methotrexate and infliximab with infliximab alone in 126 patients with CD who had initiated prednisone induction therapy (15-40 mg/day) within the preceding 6 weeks. Patients were assigned randomly to groups given methotrexate at an initial weekly dose of 10 mg, escalating to 25 mg/week (n = 63), or placebo (n = 63). Both groups received infliximab (5 mg/kg of body weight) at weeks 1, 3, 7, and 14, and every 8 weeks thereafter. Prednisone was tapered, beginning at week 1, and discontinued no later than week 14. The primary outcome was time to treatment failure, defined as a lack of prednisone-free remission (CD Activity Index, <150) at week 14 or failure to maintain remission through week 50.

RESULTS

Patients' baseline characteristics were similar between groups. By week 50, the actuarial rate of treatment failure was 30.6% in the combination therapy group compared with 29.8% in the infliximab monotherapy group (P = .63; hazard ratio, 1.16; 95% confidence interval, 0.62-2.17). Prespecified subgroup analyses failed to show a benefit in patients with short disease duration or an increased level of C-reactive protein. No clinically meaningful differences were observed in secondary outcomes. Combination therapy was well tolerated.

CONCLUSIONS

The combination of infliximab and methotrexate, although safe, was no more effective than infliximab alone in patients with CD receiving treatment with prednisone. ClincialTrials.gov number, NCT00132899.

Extracorporeal photopheresis (ECP) in patients with steroid-dependent Crohn's disease: an open-label, multicenter, prospective trial

BACKGROUND

Extracorporeal photopheresis (ECP) involves ex vivo leukocyte treatment with methoxsalen and UVA light to generate a tolerogenic response. A previous trial demonstrated that ECP permits corticosteroid withdrawal in steroid-dependent Crohn's disease (CD) patients who were in clinical remission. We studied the effect of ECP on steroid withdrawal in steroid-dependent CD.

METHODS

Patients with CD for ≥ 6 months, in remission at baseline while on steroids, but who had failed at ≥ 1 steroid withdrawal were included. Patients received two ECP treatments every 2 weeks for the 24-week steroid tapering period and underwent steroid-tapering. Patients completing steroid tapering could receive maintenance ECP (two treatments/week) every month for 24 weeks.

RESULTS

Thirty-one patients (Crohn's Disease Activity Index [CDAI] score 91; Inflammatory Bowel Disease Questionnaire [IBDQ] 172.5) were enrolled (baseline corticosteroid dose, 20 mg/day); 65% were refractory to/intolerant of anti-tumor necrosis factor (TNF) agents or immunosuppressants. After 24 weeks of ECP, 7 of 31 (22.6%) patients discontinued steroids while maintaining a CDAI of <150. At week 24, the steroid dose for the remaining patients on corticosteroids was 10 mg (P < 0.003 vs. baseline) with a CDAI of 110 and an IBDQ of 179. Following maintenance treatment, three patients remained in steroid-free remission. The 10 patients in the study and receiving ECP at week 48 had a steroid dose of 3.5 mg with a CDAI of 40 and an IBDQ of 188.

CONCLUSIONS

ECP permitted discontinuation or reduction of steroids in a population of refractory steroid-dependent CD patients. ECP may be useful in permitting steroid withdrawal in selected steroid-dependent CD patients. Ideally, these results need to be confirmed in a "sham-controlled clinical trial.

The early management of pancreatitis associated with hypertriglyceridaemia

INTRODUCTION

In triglyceridaemia-associated pancreatitis, decreasing the serum triglyceride level below 5.65 mmol/l alleviates abdominal pain and is purported to improve outcome. We analysed hypertriglyceride level normalisation and outcome in a patient cohort of acute pancreatitis.

PATIENTS AND METHODS

Patients presenting with pancreatitis and hypertriglyceridaemia were assessed. All patients with presenting triglycerides levels >10 mmol/l were assessed for resolution to a level below 5.65 mmol/l at days 3 and 5. Patients with triglyceride levels in excess of 10 mmol/l were treated with either standard supportive therapy or an insulin dextrose infusion.

RESULTS

In the period June 2001 to April 2008, there were 503 admissions of 439 patients with a diagnosis of acute pancreatitis; 26 (6%) had hypertriglyceridaemia >10 mmol/l at admission. Standard therapy was used in all patients; in 6 patients, it was the sole therapy. A dextrose and insulin infusion was used in 20 cases. On day 3, 7 (32%) of the measured triglyceride levels had fallen below 5.65 mmol/l and, on day 5, all but 4 (83%) were <5.65 mmol/l. Three patients died.

CONCLUSION

Standard therapy was equivalent to the use of dextrose and insulin in the resolution of hypertriglyceridaemia. Our methods to reduce triglyceride levels produce morbidity and mortality rates similar to those attained when alternate lipid-lowering strategies are employed.

Consultants in Scotland: survey of educational qualifications, experience and needs of Scottish consultants

AIMS

To survey Scotland's NHS consultants regarding their teaching roles; educational qualifications/training; attitudes to educational qualifications; perceptions of health boards' attitudes to educational activities; usefulness of various educational courses and preferred delivery methods.

METHODS

Postal questionnaire (n=3615).

RESULTS

Sixty two percent response rate (n=2246). 98% had one or more roles in education/training. 54% spent more time in educational roles than job-plan allocations. 6% had educational qualifications. 30% rated educational qualifications valuable to their educational role; 21% to their career. 48% had not attended any educational training. 19% of respondents rated their health board as supportive of their educational activities. Respondents rated dealing with underperforming students (74%), dealing with challenging behaviour (63%), appraising students (63%), trainee assessment (61%) and feedback (58%) as the most useful topics.

CONCLUSIONS

Scottish consultant involvement in educational activities is virtually universal but consultants perceive they need more time than allocated in job plans. Most consultants had no teaching qualifications. Nearly half had no formal training for educational activities. Educational qualifications were valued by a minority regarding both career development and educational activities. Increased access to staff development for teaching is required as NHS sources are not meeting the need for teacher training of consultant staff.

Optimism/pessimism and health-related quality of life during pregnancy across three continents: a matched cohort study in China, Ghana, and the United States

BACKGROUND

Little is known about how optimism/pessimism and health-related quality of life compare across cultures.

METHODS

Three samples of pregnant women in their final trimester were recruited from China, Ghana, and the United States (U.S.). Participants completed a survey that included the Life Orientation Test - Revised (LOT-R, an optimism/pessimism measure), the Short Form 12 (SF-12, a quality of life measure), and questions addressing health and demographic factors. A three-country set was created for analysis by matching women on age, gestational age at enrollment, and number of previous pregnancies. Anovas with post-hoc pairwise comparisons were used to compare results across the cohorts. Multivariate regression analysis was used to create a model to identify those variables most strongly associated with optimism/pessimism.

RESULTS

LOT-R scores varied significantly across cultures in these samples, with Ghanaian pregnant women being the most optimistic and least pessimistic and Chinese pregnant women being the least optimistic overall and the least pessimistic in subscale analysis. Four key variables predicted approximately 20% of the variance in overall optimism scores: country of origin (p = .006), working for money (p = .05); level of education (p = .002), and ever being treated for emotional issues with medication (p < .001). Quality of life scores also varied by country in these samples, with the most pronounced difference occurring in the vitality measure. U.S. pregnant women reported far lower vitality scores than both Chinese and Ghanaian pregnant women in our sample.

CONCLUSION

This research raises important questions regarding what it is about country of origin that so strongly influences optimism/pessimism among pregnant women. Further research is warranted exploring underlying conceptualization of optimism/pessimism and health related quality of life across countries.

Dyslipidaemic pancreatitis clinical assessment and analysis of disease severity and outcomes

INTRODUCTION

The relationship between pancreatitis and dyslipidaemia is unclear.

PATIENTS AND METHODS

Admissions with acute pancreatitis were prospectively evaluated. A comparison of the demographic profile, aetiology, disease severity scores, complications and deaths was made in relationship to the lipid profiles.

RESULTS

From June 2001 to May 2005, there were 230 admissions. The pancreatitis was associated with alcohol (63%), gallstones (18%), idiopathic (9%) and isolated dyslipidaemia (10%). Dyslipidaemia was significantly different between the two predominant race groups: Indian 50.5% and African 17.9% (p < 0.000017). Seventy-eight (34%) had associated dyslipidaemia and 152 (66%) were normolipaemic at admission. The average body mass index was higher in the dyslipidaemic group (27 +/- 6) than in the normolipaemic group (24.5 +/- 6.20; p = 0.004). The mortality rate was similar between the dyslipidaemic and normolipaemic patients (10 and 8%, respectively) and unrelated to race (p = 0.58). The 9 deaths in the dyslipidaemic group occurred in those with persistent hypertriglyceridaemia irrespective of its level (p = 0.003).

CONCLUSION

Dyslipidaemic pancreatitis was more common in the Indian ethnic group. Adverse outcomes in those with dyslipidaemia were predominantly associated with hypertriglyceridaemia.

Preduodenal portal vein: a potential laparoscopic cholecystectomy nightmare

Variations of biliary anatomy are well described. Those of most relevance to the operative surgeon are the variations of the extrahepatic ducts and their relationships to the right hepatic artery and its branches. We describe another even rarer congenital anomaly of a preduodenal portal vein. Its embryological derivation and presentation are discussed to heighten awareness of its recognition and reduce the potential of a serious operative misadventure.

Acute pancreatitis: demographics, aetiological factors and outcomes in a regional hospital in South Africa

INTRODUCTION

The spectrum of aetiologies and outcomes of acute pancreatitis in South African settings is under-reported. We report our experience at a regional hospital and compare it with international norms.

PATIENTS AND METHODS

Data were prospectively collected on all admissions of patients with acute pancreatitis to a regional hospital during the period June 2001-April 2006. The causes of the pancreatitis were noted and complications and mortality rate were determined.

RESULTS

From June 2001 to April 2006 there were 322 admissions of 282 patients with acute pancreatitis. The median age was 37 years (range 13-73 years). There were 94 females and 188 males. Episodes of pancreatitis were associated with alcohol consumption in 62% of cases and with gallstones in 14%; 4% of cases were associated with both gallstones and alcohol consumption, 8% with dyslipidaemia and 5% with retroviral disease. In 15% of admissions local complications developed, and 9% of admissions ended in death of the patient. Of the 28 deaths, 71% occurred in the first 2 weeks.

CONCLUSIONS

As in other South African reports, alcohol was the main cause of pancreatitis. Outcomes in this series are similar to those in Western studies except that the majority of deaths occurred early, implying that improved supportive care may improve overall survival.

Pancreatico-enterostomy for isolated main pancreatic duct disruption

BACKGROUND

We present our experiences with isolated main pancreatic duct injuries due to blunt trauma, managed by pancreatico-enterostomies.

METHODS

This is a retrospective study of seven patients, one female and six males who presented between 1997 and 2005, whose ages ranged from 10 to 54 years. Three were due to motor vehicle accidents, two due to blunt assault, one pedestrian vehicle accident and one go-cart accident. Four presented acutely and were managed surgically within 24h; two were delayed by 3 days and one by 14 days. Six had pre-operative CT scans; one had an ERCP confirming ductal transection by contrast extravasation.

RESULTS

Five pancreatico-gastrostomies and two pancreatico-jejenostomies were performed. Three patients complicated; one by biliary cutaneous fistula after a left hepatic segmentectomy, one with an amylase-rich low output fistula and one with haematemesis, for which no cause could be identified. All complications were managed conservatively. Post-operative follow-up ranged between 4 and 20 weeks. No deaths occurred.

CONCLUSION

In a stable patient, pancreatico-enterostomy for an isolated main pancreatic duct injury appears to be a viable option and simpler to perform than distal pancreatectomy with splenic preservation. Furthermore, it has the advantage of pancreatic tissue and spleen preservation and a low fistula rate. The authors believe pancreatico-gastrostomy to be the easier to perform.

The effect of excessive tibial torsion on the capacity of muscles to extend the hip and knee during single-limb stance

Excessive tibial torsion, a rotational deformity about the long axis of the tibia, is common in patients with cerebral palsy who walk with a crouch gait. Previous research suggests that this deformity may contribute to crouch gait by reducing the capacity of soleus to extend the knee; however, the effects of excess external torsion on the capacity of other muscles to extend the stance limb during walking are unknown. A computer model of the musculoskeletal system was developed to simulate a range of tibial torsion deformities. A dynamic analysis was then performed to determine the effect of these deformities on the capacity of lower limb muscles to extend the hip and knee at body positions corresponding to the single-limb stance phase of a normal gait cycle. Analysis of the model confirmed that excessive external torsion reduces the extension capacity of soleus. In addition, our analysis revealed that several important muscles crossing the hip and knee are also adversely affected by excessive tibial torsion. With a tibial torsion deformity of 30 degrees , the capacities of soleus, posterior gluteus medius, and gluteus maximus to extend both the hip and knee were all reduced by over 10%. Since a tibial torsion deformity reduces the capacity of muscles to extend the hip and knee, it may be a significant contributor to crouch gait, especially when greater than 30 degrees from normal, and thus should be considered by clinicians when making treatment decisions.

A single surgical unit's experience with abdominal tuberculosis in the HIV/AIDS era

INTRODUCTION

Human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) has resulted in a resurgence of abdominal tuberculosis in South Africa, and these patients often present to general surgeons. We describe a single-hospital experience in a region of high HIV prevalence.

METHODS

A prospective database of all patients with suspected abdominal tuberculosis was maintained from January 2003 until July 2005.

RESULTS

There were 67 patients (20 men, 47 women) with an average age of 32 years (range 27-61 years). The erythrocyte sedimentation rate was universally elevated (105 +/- 23). Altogether, 23 patients were HIV-positive and 7 were HIV-negative. The status was unknown in the remainder. Chest radiographs demonstrated an abnormality in 17 patients (22%). Abdominal ultrasonography was performed in 59 patients and computed tomography in 12. Twelve laparotomies were performed, seven as emergencies. None in the elective laparotomy group died, whereas the mortality rate in the emergency group was 60%. Laparoscopy was insufficient for a variety of reasons. Two patients underwent appendectomy and two excision of a perianal fistula. Two patients underwent biopsy of a palpable subcutaneous node, which confirmed the diagnosis in both cases. A definitive diagnosis was achieved in all 12 patients subjected to laparotomy and at colonoscopic biopsy in 2, lymph node biopsy in 2, appendectomy in 2, perianal fistulectomy in 2, and percutaneous drainage in 2. In the remaining 47 patients the diagnosis was made on the basis of the clinical presentation and radiologic imaging. The patients were commenced on antituberculous therapy. The in-hospital mortality in this group was 10%. Therapy was continued at a centralized tuberculosis facility independent of the hospital. Surgical follow-up was poor, with only five (7%) patients completing the 6-month review at a surgical clinic.

CONCLUSIONS

A resurgence in tuberculosis during the HIV era produces a new spectrum of presentations for the surgeon. Emergency surgery is associated with high mortality. Bacterial and histologic evidence of infection are difficult to obtain, and indirect clinical and imaging evidence are used to commence a trial of therapy. A short-term clinical response is regarded as proof of disease. Lack of follow-up means that the efficacy of this strategy is unproven. Health policy changes are needed to enable appropriate surgical follow-up to determine the most effective management algorithm.

Palliation of malignant hilar obstruction at a single centre--review of operative and non-operative techniques

INTRODUCTION

Jaundice secondary to a malignant hilar obstruction can be relieved by operative bypass or percutaneous stenting. Comparative trials involving these techniques are scarce. We reviewed our experience with these competing techniques in the palliation of malignant hilar obstruction.

PATIENTS AND METHODS

All patients with malignant hilar obstruction managed at our institution during the period 1992-2002 were identified for review.

RESULTS

A total of 36 deeply jaundiced patients with hilar obstruction were identified. Twenty-two patients underwent exploration with the intention of performing an operative bypass and 14 patients underwent percutaneous transhepatic cholangiography (PTC) with intention to stent. Procedure-related mortality was similar in both groups. Morbidity was much higher in the operative group. Effective symptom relief was achieved with both techniques. In the PTC group recurrent biliary obstruction in 2 patients necessitated salvage non-operative procedures. Although survival rates were slightly longer in the operative group, this was not significant. There were no long-term survivors.

CONCLUSION

Operative bypass provides better sustained relief of jaundice than PTC. However long-term survival in both groups is poor and operative bypass is best reserved for younger patients with no technical contraindications. Despite early and late procedural failures PTC is the method of choice for patients with advanced-stage disease and those with significant co-morbidities.

The current standard of care in the periprocedural management of the patient with obstructive jaundice

This review provides a literature-based guide to the optimal management of the patient with obstructive jaundice with emphasis placed on prevention of complications.