Rescue from complications after pancreaticoduodenectomies at a low-volume Caribbean center: Value of tailored peri-pancreatectomy protocols.

BACKGROUND: Pancreaticoduodenectomy (PD) is a technically complex operation, with a relatively high risk for complications. The ability to rescue patients from post-PD complications is as a recognized quality measure. Tailored protocols were instituted at our low volume facility in the year 2013. AIM: To document the rate of rescue from post-PD complications with tailored protocols in place as a measure of quality. METHODS: A retrospective audit was performed to collect data from patients who experienced major post-PD complications at a low volume pancreatic surgery unit in Trinidad and Tobago between January 1, 2013 and June 30, 2023. Standardized definitions from the International Study Group of Pancreatic Surgery were used to define post-PD complications, and the modified Clavien-Dindo classification was used to classify post-PD complications. RESULTS: Over the study period, 113 patients at a mean age of 57.5 years (standard deviation [SD] ± 9.23; range: 30-90; median: 56) underwent PDs at this facility. Major complications were recorded in 33 (29.2%) patients at a mean age of 53.8 years (SD: ± 7.9). Twenty-nine (87.9%) patients who experienced major morbidity were salvaged after aggressive treatment of their complication. Four (3.5%) died from bleeding pseudoaneurysm (1), septic shock secondary to a bile leak (1), anastomotic leak (1), and myocardial infarction (1). There was a significantly greater salvage rate in patients with American Society of Anesthesiologists scores ≤ 2 (93.3% vs 25%; P = 0.0024). CONCLUSION: This paper adds to the growing body of evidence that volume alone should not be used as a marker of quality for patients requiring PD. Despite low volumes at our facility, we demonstrated that 87.9% of patients were rescued from major complications. We attributed this to several factors including development of rescue protocols, the competence of the pancreatic surgery teams and continuous, and adaptive learning by the entire institution, culminating in the development of tailored peri-pancreatectomy protocols.

Simultaneous Quantitation and Discovery (SQUAD) Analysis: Combining the Best of Targeted and Untargeted Mass Spectrometry-Based Metabolomics.

Untargeted and targeted approaches are the traditional metabolomics workflows acquired for a wider understanding of the metabolome under focus. Both approaches have their strengths and weaknesses. The untargeted, for example, is maximizing the detection and accurate identification of thousands of metabolites, while the targeted is maximizing the linear dynamic range and quantification sensitivity. These workflows, however, are acquired separately, so researchers compromise either a low-accuracy overview of total molecular changes (i.e., untargeted analysis) or a detailed yet blinkered snapshot of a selected group of metabolites (i.e., targeted analysis) by selecting one of the workflows over the other. In this review, we present a novel single injection simultaneous quantitation and discovery (SQUAD) metabolomics that combines targeted and untargeted workflows. It is used to identify and accurately quantify a targeted set of metabolites. It also allows data retro-mining to look for global metabolic changes that were not part of the original focus. This offers a way to strike the balance between targeted and untargeted approaches in one single experiment and address the two approaches' limitations. This simultaneous acquisition of hypothesis-led and discovery-led datasets allows scientists to gain more knowledge about biological systems in a single experiment.

Whipple's operation with a modified centralization concept: A model in low-volume Caribbean centers.

Conventional data suggest that complex operations, such as a pancreaticoduodenectomy (PD), should be limited to high volume centers. However, this is not practical in small, resource-poor countries in the Caribbean. In these settings, patients have no option but to have their PDs performed locally at low volumes, occasionally by general surgeons. In this paper, we review the evolution of the concept of the high-volume center and discuss the feasibility of applying this concept to low and middle-income nations. Specifically, we discuss a modification of this concept that may be considered when incorporating PD into low-volume and resource-poor countries, such as those in the Caribbean. This paper has two parts. First, we performed a literature review evaluating studies published on outcomes after PD in high volume centers. The data in the Caribbean is then examined and we discuss the incorporation of this operation into resource-poor hospitals with modifications of the centralization concept. In the authors' opinions, most patients who require PD in the Caribbean do not have realistic opportunities to have surgery in high-volume centers in developed countries. In these settings, their only options are to have their operations in the resource-poor, low-volume settings in the Caribbean. However, post-operative outcomes may be improved, despite low-volumes, if a modified centralization concept is encouraged.

Review of minimally invasive pancreas surgery and opinion on its incorporation into low volume and resource poor centres.

Pancreatic surgery has been one of the last areas for the application of minimally invasive surgery (MIS) because there are many factors that make laparoscopic pancreas resections difficult. The concept of service centralization has also limited expertise to a small cadre of high-volume centres in resource rich countries. However, this is not the environment that many surgeons in developing countries work in. These patients often do not have the opportunity to travel to high volume centres for care. Therefore, we sought to review the existing data on MIS for the pancreas and to discuss. In this paper, we review the evolution of MIS on the pancreas and discuss the incorporation of this service into low-volume and resource-poor countries, such as those in the Caribbean. This paper has two parts. First, we performed a literature review evaluating all studies published on laparoscopic and robotic surgery of the pancreas. The data in the Caribbean is examined and we discuss tips for incorporating this operation into resource poor hospital practice. Low pancreatic case volume in the Caribbean, and financial barriers to MIS in general, laparoscopic distal pancreatectomy, enucleation and cystogastrostomy are feasible operations to integrate in to a resource-limited healthcare environment. This is because they can be performed with minimal to no consumables and require an intermediate MIS skillset to complement an open pancreatic surgeon's peri-operative experience.

Anatomic variations of the intra-hepatic biliary tree in the Caribbean: A systematic review.

BACKGROUND: In the classic descriptions of the human liver, the common hepatic duct forms at the confluence of left and right hepatic ducts. Many authors have documented variations in the intra-hepatic ductal system, but to the best of our knowledge there has been no report on bile duct variations in Caribbean populations. AIM: To evaluate the variations in bile duct anatomy using magnetic resonance cholangiography (MRC) in unselected patients at a major hepatobiliary referral centre in the Eastern Caribbean. Knowledge of the intra-hepatic biliary anatomy is important to optimize service delivery for any physician treating liver and biliary disorders. METHODS: This study was carried out at a tertiary referral hospital for hepatobiliary diseases in the Eastern Caribbean. We retrospectively evaluated magnetic resonance cholangiograms in 152 consecutive patients at this facility over a two-year period from April 1, 2017 to March 31, 2019. Two consultant radiologists experienced in MRC interpretation reviewed all scans and described biliary anatomy according to the Huang's classification. A systematic review of published studies was performed and relevant data were extracted in order to calculate the global prevalence of each biliary variant. The variants in our population were compared to the global population. RESULTS: There were 152 MRCs evaluated in this study in 86 males and 66 females. There were 109 (71.7%) persons with "classic" biliary anatomy (type A1) and variants were present in 43 (28.3%) persons. There was no statistical relationship between the presence of anatomic variants and gender or ethnicity. We encountered the following variants: 29 (19.1%) type A2, 7 (4.6%) type A3, 6 (3.95%) type A4, 0 type A5 and a single variant (quadrification) that did not fit the classification system. Compared to the global prevalence, our population had a significantly greater occurrence of A1 anatomy (71.7% vs 62.6%; P = 0.0227) and A2 trifurcations (19.1% vs 11.5%; P = 0.0069), but a significantly lower incidence of A3 variants (4.61% vs 11.5%; P = 0.0047). CONCLUSION: There are significant differences in intra-hepatic biliary anatomy in this unselected Eastern Caribbean population compared to global statistics. Specifically, persons of Caribbean descent have a greater incidence of Huang A2 trifurcations and a lower incidence of Huang A3 variants.

Surgical relevance of anatomic variations of the right hepatic vein.

BACKGROUND: Variations in the anatomy of hepatic veins are of interest to transplant surgeons, interventional radiologists, and other medical practitioners who treat liver diseases. The drainage patterns of the right hepatic veins (RHVs) are particularly relevant to transplantation services. AIM: The aim was to identify variations of the patterns of venous drainage from the right side of the liver. To the best of our knowledge, there have been no reports on RHV variations in in a Caribbean population. METHODS: Two radiologists independently reviewed 230 contrast-enhanced computed tomography scans performed in 1 year at a hepatobiliary referral center. Venous outflow patterns were observed and RHV variants were described as: (1) Tributaries of the RHV; (2) Variations at the hepatocaval junction (HCJ); and (3) Accessory RHVs. RESULTS: A total of 118 scans met the inclusion criteria. Only 39% of the scans found conventional anatomy of the main hepatic veins. Accessory RHVs were present 49.2% and included a well-defined inferior RHV draining segment VI (45%) and a middle RHV (4%). At the HCJ, 83 of the 118 (70.3%) had a superior RHV that received no tributaries within 1 cm of the junction (Nakamura and Tsuzuki type I). In 35 individuals (29.7%) there was a short superior RHV with at least one variant tributary. According to the Nakamura and Tsuzuki classification, there were 24 type II variants (20.3%), six type III variants (5.1%) and, five type IV variants (4.2%). CONCLUSION: There was significant variation in RHV patterns in this population, each with important relevance to liver surgery. Interventional radiologists and hepatobiliary surgeons practicing in the Caribbean must be cognizant of these differences in order to minimize morbidity during invasive procedures.

Loss of CLN3, the gene mutated in juvenile neuronal ceroid lipofuscinosis, leads to metabolic impairment and autophagy induction in retinal pigment epithelium.

Juvenile neuronal ceroid lipofuscinosis (JNCL, aka. juvenile Batten disease or CLN3 disease) is a lysosomal storage disease characterized by progressive blindness, seizures, cognitive and motor failures, and premature death. JNCL is caused by mutations in the Ceroid Lipofuscinosis, Neuronal 3 (CLN3) gene, whose function is unclear. Although traditionally considered a neurodegenerative disease, CLN3 disease displays eye-specific effects: Vision loss not only is often one of the earliest symptoms of JNCL, but also has been reported in non-syndromic CLN3 disease. Here we described the roles of CLN3 protein in maintaining healthy retinal pigment epithelium (RPE) and normal vision. Using electroretinogram, fundoscopy and microscopy, we showed impaired visual function, retinal autofluorescent lesions, and RPE disintegration and metaplasia/hyperplasia in a Cln3 ~ 1 kb-deletion mouse model [1] on C57BL/6J background. Utilizing a combination of biochemical analyses, RNA-Seq, Seahorse XF bioenergetic analysis, and Stable Isotope Resolved Metabolomics (SIRM), we further demonstrated that loss of CLN3 increased autophagic flux, suppressed mTORC1 and Akt activities, enhanced AMPK activity, and up-regulated gene expression of the autophagy-lysosomal system in RPE-1 cells, suggesting autophagy induction. This CLN3 deficiency induced autophagy induction coincided with decreased mitochondrial oxygen consumption, glycolysis, the tricarboxylic acid (TCA) cycle, and ATP production. We also reported for the first time that loss of CLN3 led to glycogen accumulation despite of impaired glycogen synthesis. Our comprehensive analyses shed light on how loss of CLN3 affect autophagy and metabolism. This work suggests possible links among metabolic impairment, autophagy induction and lysosomal storage, as well as between RPE atrophy/degeneration and vision loss in JNCL.

High Flux Through the Oxidative Pentose Phosphate Pathway Lowers Efficiency in Developing Camelina Seeds.

Many seeds are green during development, and light has been shown to play a role in the efficiency with which maternally supplied substrates are converted into storage compounds. However, the effects of light on the fluxes through central metabolism that determine this efficiency are poorly understood. Here, we used metabolic flux analysis to determine the effects of light on central metabolism in developing embryos of false flax (Camelina sativa). Metabolic efficiency in C. sativa is of interest because, despite its growing importance as a model oilseed and engineering target and its potential as a biofuel crop, its yields are lower than other major oilseed species. Culture conditions under which steady-state growth and composition of developing embryos match those in planta were used to quantify substrate uptake and respiration rates. The carbon conversion efficiency (CCE) was 21% ± 3% in the dark and 42% ± 4% under high light. Under physiological illumination, the CCE (32% ± 2%) was substantially lower than in green and nongreen oilseeds studied previously. 13C and 14C isotopic labeling experiments were used together with computer-aided modeling to map fluxes through central metabolism. Fluxes through the oxidative pentose phosphate pathway (OPPP) were the principal source of CO2 production and strongly negatively correlated with CCE across light levels. OPPP fluxes were greatly in excess of demand for NAD(P)H for biosynthesis and larger than those measured in other systems. Excess reductant appears to be dissipated via cyanide-insensitive respiration. OPPP enzymes therefore represent a potential target for increasing efficiency and yield in C. sativa.

Comparative evaluation of salivary zinc concentration in autistic and healthy children in mixed dentition age group-pilot study.

CONTEXT: Autism prevalence is increasing, with current estimates at 1/68-1/50 individuals diagnosed with autism. Diagnosis is based on behavioral assessments. Early diagnosis and intervention are known to greatly improve functional outcomes in people with autism. Diagnosis, treatment monitoring, and prognosis of autistic children's symptoms could be facilitated with biomarkers to complement behavioral assessments. AIMS: The aim of this study is to compare and evaluate salivary zinc concentration in saliva samples of autistic and healthy children in mixed dentition age group. SETTINGS AND DESIGN: Cross-sectional comparative study carried out in dental college and special child school. Unstimulated whole saliva collected for finding a biomarker. SUBJECTS AND METHODS: Unstimulated whole saliva sample was collected from 10 autistic and 10 healthy children in mixed dentition age group. Diluted saliva sample was then subjected to inductively coupled plasma emission spectroscopy for the estimation of salivary zinc concentration. STATISTICAL ANALYSIS USED: Mann-Whitney U-test. RESULTS: In children with autism salivary zinc concentration showed a linear equation when compared to healthy children. CONCLUSIONS: The low salivary zinc concentration in autistic children can reveal the pathogenesis of autism.

Identification of regulatory network hubs that control lipid metabolism in Chlamydomonas reinhardtii.

Microalgae-based biofuels are promising sources of alternative energy, but improvements throughout the production process are required to establish them as economically feasible. One of the most influential improvements would be a significant increase in lipid yields, which could be achieved by altering the regulation of lipid biosynthesis and accumulation. Chlamydomonas reinhardtii accumulates oil (triacylglycerols, TAG) in response to nitrogen (N) deprivation. Although a few important regulatory genes have been identified that are involved in controlling this process, a global understanding of the larger regulatory network has not been developed. In order to uncover this network in this species, a combined omics (transcriptomic, proteomic and metabolomic) analysis was applied to cells grown in a time course experiment after a shift from N-replete to N-depleted conditions. Changes in transcript and protein levels of 414 predicted transcription factors (TFs) and transcriptional regulators (TRs) were monitored relative to other genes. The TF and TR genes were thus classified by two separate measures: up-regulated versus down-regulated and early response versus late response relative to two phases of polar lipid synthesis (before and after TAG biosynthesis initiation). Lipidomic and primary metabolite profiling generated compound accumulation levels that were integrated with the transcript dataset and TF profiling to produce a transcriptional regulatory network. Evaluation of this proposed regulatory network led to the identification of several regulatory hubs that control many aspects of cellular metabolism, from N assimilation and metabolism, to central metabolism, photosynthesis and lipid metabolism.

Optimal line of hepatotomy for left lateral living donor liver transplantation according to the anatomical variations of left hepatic duct system.

Multiple duct anastomoses during LLS transplantation increase the incidence of biliary complications. The optimal plane of hepatotomy that results in the least number of bile ducts at the surface was investigated according to LHD variations. Ducts of 30 human livers were injected with resin and LHD branching on 3D-CT reconstructions were analyzed. Ducts on the virtual hepatotomy surface were estimated in three splitting lines. Variations with subtypes were described. Ia (66.7%): ducts from segments (S.) II-III form a common trunk and S.IV duct joins it. Ib (10%): common trunk formed by ducts from S.II-S.III while S.IV duct joins the common hepatic duct. IIa (16.67%): S.IV duct drains into S.III duct. IIc (3.33%): S.IV duct drains into both S.II and S.III ducts. III (3.33%): trifurcation of S.II, S.III and S.IV ducts. When the virtual hepatotomy line was on the FL, there was a single duct for the anastomosis in 30% of cases but two, three, or four ducts in 53.3%, 10%, and 3.3%, respectively. Division 1 cm to the right of the FL resulted in one duct (70%), but S.IV duct injury may occur. LLS hepatotomy should not necessarily be performed along the FL. Variations must be taken into consideration to minimize the number of biliary anastomoses during liver implantation.

The regulation of photosynthetic structure and function during nitrogen deprivation in Chlamydomonas reinhardtii.

The accumulation of carbon storage compounds by many unicellular algae after nutrient deprivation occurs despite declines in their photosynthetic apparatus. To understand the regulation and roles of photosynthesis during this potentially bioenergetically valuable process, we analyzed photosynthetic structure and function after nitrogen deprivation in the model alga Chlamydomonas reinhardtii. Transcriptomic, proteomic, metabolite, and lipid profiling and microscopic time course data were combined with multiple measures of photosynthetic function. Levels of transcripts and proteins of photosystems I and II and most antenna genes fell with differing trajectories; thylakoid membrane lipid levels decreased, while their proportions remained similar and thylakoid membrane organization appeared to be preserved. Cellular chlorophyll (Chl) content decreased more than 2-fold within 24 h, and we conclude from transcript protein and (13)C labeling rates that Chl synthesis was down-regulated both pre- and posttranslationally and that Chl levels fell because of a rapid cessation in synthesis and dilution by cellular growth rather than because of degradation. Photosynthetically driven oxygen production and the efficiency of photosystem II as well as P700(+) reduction and electrochromic shift kinetics all decreased over the time course, without evidence of substantial energy overflow. The results also indicate that linear electron flow fell approximately 15% more than cyclic flow over the first 24 h. Comparing Calvin-Benson cycle transcript and enzyme levels with changes in photosynthetic (13)CO2 incorporation rates also pointed to a coordinated multilevel down-regulation of photosynthetic fluxes during starch synthesis before the induction of high triacylglycerol accumulation rates.

The response of Chlamydomonas reinhardtii to nitrogen deprivation: a systems biology analysis.

Drastic alteration in macronutrients causes large changes in gene expression in the photosynthetic unicellular alga Chlamydomonas reinhardtii. Preliminary data suggested that cells follow a biphasic response to this change hinging on the initiation of lipid accumulation, and we hypothesized that drastic repatterning of metabolism also followed this biphasic modality. To test this hypothesis, transcriptomic, proteomic, and metabolite changes that occur under nitrogen (N) deprivation were analyzed. Eight sampling times were selected covering the progressive slowing of growth and induction of oil synthesis between 4 and 6 h after N deprivation. Results of the combined, systems-level investigation indicated that C. reinhardtii cells sense and respond on a large scale within 30 min to a switch to N-deprived conditions turning on a largely gluconeogenic metabolic state, which then transitions to a glycolytic stage between 4 and 6 h after N depletion. This nitrogen-sensing system is transduced to carbon- and nitrogen-responsive pathways, leading to down-regulation of carbon assimilation and chlorophyll biosynthesis, and an increase in nitrogen metabolism and lipid biosynthesis. For example, the expression of nearly all the enzymes for assimilating nitrogen from ammonium, nitrate, nitrite, urea, formamide/acetamide, purines, pyrimidines, polyamines, amino acids and proteins increased significantly. Although arginine biosynthesis enzymes were also rapidly up-regulated, arginine pool size changes and isotopic labeling results indicated no increased flux through this pathway.

Changes in transcript abundance in Chlamydomonas reinhardtii following nitrogen deprivation predict diversion of metabolism.

Like many microalgae, Chlamydomonas reinhardtii forms lipid droplets rich in triacylglycerols when nutrient deprived. To begin studying the mechanisms underlying this process, nitrogen (N) deprivation was used to induce triacylglycerol accumulation and changes in developmental programs such as gametogenesis. Comparative global analysis of transcripts under induced and noninduced conditions was applied as a first approach to studying molecular changes that promote or accompany triacylglycerol accumulation in cells encountering a new nutrient environment. Towards this goal, high-throughput sequencing technology was employed to generate large numbers of expressed sequence tags of eight biologically independent libraries, four for each condition, N replete and N deprived, allowing a statistically sound comparison of expression levels under the two tested conditions. As expected, N deprivation activated a subset of control genes involved in gametogenesis while down-regulating protein biosynthesis. Genes for components of photosynthesis were also down-regulated, with the exception of the PSBS gene. N deprivation led to a marked redirection of metabolism: the primary carbon source, acetate, was no longer converted to cell building blocks by the glyoxylate cycle and gluconeogenesis but funneled directly into fatty acid biosynthesis. Additional fatty acids may be produced by membrane remodeling, a process that is suggested by the changes observed in transcript abundance of putative lipase genes. Inferences on metabolism based on transcriptional analysis are indirect, but biochemical experiments supported some of these deductions. The data provided here represent a rich source for the exploration of the mechanism of oil accumulation in microalgae.

Long-term outcome of liver retransplantation in children.

BACKGROUND: Retransplantation of the liver is the only means of prolonging survival in children whose initial graft has failed. Patient and graft survival rates after retransplantation in most series have been inferior to rates after first transplantation. PATIENTS AND METHODS: Of 450 pediatric liver transplantations performed between January 1990 and March 2001, 50 were first retransplantations, 9 were second retransplantations, and 1 was a third retransplantation. The overall retransplantation rate was 13.3% (median age at retransplantation 4 years and median weight 15 kg). The median post-retransplantation follow-up was 73 (range, 6-139) months. RESULTS: Kaplan-Meier patient survival rates for the group (n=50) were 71.7%, 64.7%, and 64.7% at 1, 3, and 5 years, respectively. Graft survival rates were 65.6%, 56.7%, and 56.7% at 1, 3, and 5 years, respectively. This is significantly worse than rates for children undergoing first liver transplantation. There were 17 deaths, of which 9 occurred in the first month. Biliary complications occurred in 5 (10%) patients and vascular complications in 6 (12%). Improved patient and graft survival rates were observed in the later phase of the program, although the difference was not significant. Higher preoperative serum creatinine (P=0.001) and serum bilirubin (P=0.02) levels were associated with a higher postoperative mortality. CONCLUSION: Results of retransplantation in children remain inferior to those after first transplantation. There is a trend toward improving results. Liver retransplantation makes an important contribution to overall survival in children.

Results of split liver transplantation in children.

OBJECTIVE: To analyze the outcome of 80 consecutive pediatric split liver transplants performed at the authors' center between 1994 and 2000. SUMMARY BACKGROUND DATA: Split liver transplantation has become an accepted method of increasing the number of available grafts for pediatric liver transplant recipients. METHODS: The age of the patients at the time of transplantation ranged from 5 days to 16 years (median 3 years). Sixteen transplants were performed for acute liver failure and 64 for chronic liver failure. The ex situ splitting technique was used for all but four grafts. Fourteen livers were split for two pediatric recipients. Posttransplant follow-up ranged from 6 to 84 months (median 42 months). RESULTS: Overall patient survival at 6 months follow-up was 96.2%. Graft survival at six months was 93.7%. The Kaplan-Meier patient survival rates at 1 and 3 years were 93.5% and 88.1%, and the graft survival rates were 89.7% and 86.1%, respectively. Four patients required retransplantation. In the acute group (n = 16), the patient survival rates were 93.7% at 1 year and 76.4% at 3 years; there were three deaths due to posttransplant lymphoproliferative disease (PTLD), sepsis, and chronic rejection. In the chronic group (n = 64), the 1- and 3-year patient survival rates were 93.6% and 90.9%, respectively. There were six deaths in this group. Four patients died in the first year after the transplant due to intracranial bleeding, cerebral tumor recurrence, PTLD, and chronic rejection. There were two deaths at 3 years, one due to progressive renal failure secondary to cyclosporin toxicity and the other due to sepsis, portal hypertension, and recurrent bleeding. Vascular complications occurred in six (7.5%) patients and biliary complications in seven (8.7%). CONCLUSIONS: These results, which represent the experience of a single institution over the last 6 years, indicate that ex situ split liver transplantation can be performed in children with good overall outcome and acceptable morbidity.