A New Step-Up Dual Endoscopic Approach for Large-Size Infected Pancreatic Necrosis: Percutaneous Endoscopic Necrosectomy Followed by Transluminal Endoscopic Drainage/Necrosectomy

BACKGROUND

Acute pancreatitis in 10% to 20% of cases can be associated with necrosis of the pancreatic gland, peripancreatic tissue, or both. We report a case series of a new endoscopic approach to treat infected pancreatic necrosis (IPN).

PATIENTS AND METHODS

Consecutive patients with IPN, extending from the perigastric area up to the paracolic gutters or into the pelvis, were prospectively studied from January 2017 to June 2022. The treatment protocol was radiologic percutaneous drainage as the first step, followed by fully covered metal stent placement (FC-SEMS) in the track of the catheter. Percutaneous endoscopic necrosectomy (PEN) was performed 2 to 4 days later using a flexible endoscope through the percutaneous tract. About 2 to 4 weeks later, when a matured sac was visible, EUS-guided endoscopic transluminal drainage (ETD) with lumen-apposing metal stents (LAMS) was performed. Control of sepsis with resolution of collection(s) was the primary outcome measure.

RESULTS

We included 18 patients, males in 50% of cases with age 60±12 years old. Most frequent cause of pancreatitis was biliary (7 cases) followed by alcoholic in 6 cases; in 3 cases pancreatitis was caused by hyperlipemia and in 2 cases was idiopathic. Mean size of WON was 18±2 cm. For PEN, SEMSs used were esophageal FC-SEMS. LAMS used for ETD were Hot Axios, Hot Spaxus and Nagistent. Mean time of endoscopic intervention for PEN and ETD was 18±3 and 37±4 days, respectively. In 5 cases adverse events occurred: 3 cases of overinflations resolved with introduction of Verres needles in abdomen. In 2 cases postprocedural GI bleeding required endoscopic intervention. In all cases control of sepsis was reached together with resolution of collections. No cases of deaths were observed.

CONCLUSIONS

Step-up percutaneous and transluminal endoscopic necrosectomy therapy is an effective strategy for large-size IPN with combined central and peripheral necrosis.

Acute left-sided malignant colonic obstruction: Is there a role for endoscopic stenting?

The therapy of left-sided malignant colonic obstruction continues to be one of the largest problems in clinical practice. Numerous studies on colonic stenting for neoplastic colonic obstruction have been reported in the last decades. Thereby the role of self-expandable metal stents (SEMS) in the treatment of malignant colonic obstruction has become better defined. However, numerous prospective and retrospective investigations have highlighted serious concerns about a possible worse outcome after endoscopic colorectal stenting as a bridge to surgery, particularly in case of perforation. This review analyzes the most recent evidence in order to highlight pros and cons of SEMS placement in left-sided malignant colonic obstruction.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Does the cerebellar sequential theory explain spoken language impairments? A literature review

During the past decades, converging evidence from clinical, neuroimaging and neuroanatomical studies has demonstrated the key role of the cerebellum in the processing of non-motor aspects of language. Although more is known about the way in which the cerebellum participates in the mechanisms involved in written language, there is ambiguous information on its role in other aspects of language, such as in non-motor aspects of spoken language. Thus, to contribute additional insight into this important issue, in the present work, we review several original scientific papers focusing on the most frequent non-motor spoken language impairments evidenced in patients affected by cerebellar pathology, namely, verbal working memory, grammar processing and verbal fluency impairments. Starting from the collected data, we provide a common interpretation of the spoken language disorders in cerebellar patients, suggesting that sequential processing could be the main mechanism by which the cerebellum participates in these abilities. Indeed, according to the cerebellar sequential theory, spoken language impairments could be due to altered cerebellar function to supervise, synchronize and coordinate the activity of different functional modules, affecting the correct optimization of linguistic processing.

Dilation assisted stone extraction for complex biliary lithiasis: Technical aspects and practical principles

Common bile duct stones are frequently diagnosed worldwide and are one of the main indications for endoscopic retrograde cholangio-pancreatography. Endoscopic sphincterotomy (EST) has been used for the removal of bile duct stones for the past 40 years, providing a wide opening to allow extraction. Up to 15% of patients present with complicated choledocholithiasis. In this context, additional therapeutic approaches have been proposed such as endoscopic mechanical lithotripsy, intraductal or extracorporeal lithotripsy, or endoscopic papillary large balloon dilation (EPLBD). EPLBD combined with EST was introduced in 2003 to facilitate the passage of large or multiple bile duct stones using a balloon greater than 12 mm in diameter. EPLBD without EST was introduced as a simplified technique in 2009. Dilation-assisted stone extraction (DASE) is the combination of two techniques: EPLBD and sub-maximal EST. Several studies have reported this technique as safe and effective in patients with large bile duct stones, without any increased risk of adverse events such as pancreatitis, bleeding, or perforation. Nevertheless, it is difficult to analyze the outcomes of DASE because there are no standard techniques and definitions between studies. The purpose of this paper is to provide technical guidance and specific information about the main issues regarding DASE, based on current literature and daily clinical experience in biliary referral centers.

Endoscopic ultrasound-guided biliary drainage for malignant biliary obstruction after failed ERCP in low performance status patients

BACKGROUND

Endoscopic retrograde cholangiopancreatography (ERCP) with the placement of a biliary stent is the treatment of choice for palliation of malignant obstructive jaundice. In 5-10% of cases ERCP fails. In these cases an effective alternative is endoscopic ultrasonography-guided biliary drainage (EUS-BD).

AIM

Evaluation of the principal clinical outcomes of direct transluminal EUS-BD.

PATIENTS AND METHODS

This study is a retrospective analysis. All consecutive patients with malignant obstructive jaundice, in whom ERCP had failed, were enrolled. The primary outcome was the technical success of EUS-BD defined as the correct placement of the metal or plastic stent across the stomach or duodenum to the biliary tree. The most important secondary outcomes were early and late clinical success, both linked to the decrease of bilirubin haematic level.

RESULTS

Between January 2011 and November 2017 thirty-six patients were included. Technical success was obtained in 91.6%. A clinical success, early or late was obtained in 75.8%. The ECOG performance status of less than 3 was correlated with clinical success. Adverse events occurred in 30.3% of patients.

CONCLUSIONS

EUS-BD is an effective and safe procedure.

Lack of reduction in serum alpha-fetoprotein during treatment with direct antiviral agents predicts hepatocellular carcinoma development in a large cohort of patients with hepatitis C virus-related cirrhosis

Risk of hepatocellular carcinoma (HCC) in hepatitis C virus cirrhotic patients treated with direct-acting antiviral agents (DAA) is still debating. We investigated it in a large cohort. The cohort comprised 1045 cirrhotic patients who completed treatment with DAA, with a median follow-up of 17.3 months after end of treatment (EOT), including 943 patients without history of HCC and 102 previously treated for HCC. The majority were men (59.9%), with compensated cirrhosis (88.8%), genotype 1b (44.7%). Univariate, multivariate analysis and Kaplan-Meier curves were performed to detect predictors of HCC in patients with and without reduction in alpha-fetoprotein (AFP) during treatment. SVR12 was 95.6%. HCC developed in 95 (9.9%), including 54 of 943 (5.7%) occurrent and 41 of 102 (39%) recurrent tumours. De novo were more often unifocal (P = 0.01) and curable (P = 0.03). AFP decreased from 16.1 ± 36.2 mg/dL (baseline) to 11.4 ± 55 mg/dL (EOT). At univariate analysis, predictors were a previous HCC, older age, higher model for end-stage liver disease, prolonged INR, lower platelets, baseline and EOT AFP, virological failure and no reduction in AFP during treatment. Kaplan-Meier curves showed lower incidence of HCC in patients showing any reduction in AFP (P = 0.001). Those with AFP <6 ng/mL had the lowest risk (P = 0.0002). At logistic regression, platelets (P = 0.009, OR 0.99 CI: 0.99-1.00), previous HCC (P < 0.000 01, OR: 10.76, 95% CI: 5.89-19.34) and no reduction in AFP during treatment (P = 0.0005, OR: 2.98, CI: 1.60-5.54) were independent predictors of HCC. In conclusion, risk of HCC after DAA treatment remains substantial. It is higher among patients with previous HCC, low platelets and without reduction in AFP during treatment.

Microbial translocation and T cell activation are modified by direct-acting antiviral therapy in HCV-infected patients

BACKGROUND

Microbial translocation from the gut lumen has been involved in the pathogenesis of liver damage in hepatitis C virus (HCV) infection.

AIM

To investigate the impact of direct-acting antiviral treatment on microbial translocation and T-cell activation, in patients with hepatitis C-related liver disease.

METHODS

We enrolled two groups of HCV-infected patients undergoing direct-acting antiviral treatment: patients with fibrosis ≥F3 according to Metavir (Group ≥F3); patients with hepatitis C recurrence after liver transplantation and Metavir ≥F2 (Group Liver Transplantation + ≥F2). All patients were treated with direct-acting antivirals based on ongoing guidelines. Surrogate biomarkers of microbial translocation (plasma concentrations of soluble-CD14, lipopolysaccharide-binding protein and intestinal fatty acid-binding protein) were evaluated at baseline, at first month, at the end of treatment and 3 months later. T-cell activation was measured by expression of CD38+ HLA-DR at the same time points, only in Group ≥F3.

RESULTS

There were 32 patients in Group ≥F3 and 13 in Group LT + ≥F2. At baseline, levels of soluble-CD14 and lipopolysaccharide-binding protein were significantly higher in both groups vs healthy controls. Baseline soluble-CD14 correlated with glutamic-oxalacetic transaminase (r = 0.384, P = 0.009) and glutamic-pyruvic transaminase (r = 0.293, P = 0.05). A significant decrease in plasma levels of surrogate microbial translocation biomarkers was observed during and after treatment in the two groups although values were not normalised. In Group ≥F3, CD38+ HLADR+ T-cell expression was significantly decreased by direct-acting antiviral treatment. Relapsers (9%) showed higher soluble-CD14 levels at baseline.

CONCLUSION

Surrogate microbial translocation markers and T cell activation are increased in HCV-infected patients with liver fibrosis and decrease during direct-acting antiviral treatment.

Modification of splenic stiffness on acoustic radiation force impulse parallels the variation of portal pressure induced by transjugular intrahepatic portosystemic shunt

BACKGROUND AND AIM

Spleen and liver stiffness (LS) measured by acoustic radiation force impulse (ARFI) imaging has been shown to be useful in identifying patients with portal hypertension. The study aims to establish if the modification of portal pressure induced by a transjugular intrahepatic portosystemic shunt (TIPS) parallels the modification of spleen or LS measured by ARFI in order to understand if ARFI may be used to monitor the modification of portal pressure in patients with cirrhosis.

METHODS

Thirty-eight patients with severe portal hypertension underwent LS and spleen stiffness (SS) before TIPS and 1 week after TIPS. Portal atrial gradient (PAG) was measured before and after the shunt opening.

RESULTS

Portal atrial gradient decreased significantly from 19.5 to 6 mmHg (P < 0.001). SS decreased significantly after TIPS (pre-TIPS 3.7 m/s vs post-TIPS 3. 1 m/s; P < 0.001), and LS was also significantly modified by TIPS (pre-TIPS 2.8 m/s vs post-TIPS 2.4 m/s; P = 0.003). PAG and SS values measured before and after TIPS were significantly correlated (r = 0.56; P < 0.001); on the other hand, PAG and LS were not (r = 0.19; P = 0.27). Two patients developed a persistent hepatic encephalopathy refractory to medical treatment and were submitted to the reduction of the stent diameter. The modification of SS was parallel to the modification of PAG.

CONCLUSION

Spleen stiffness is superior to LS in detecting the modification of portal pressure induced by TIPS. This makes SS a potential non-invasive method to monitor the modification of portal hypertension. Further investigations are needed to establish applicability and clinical utility of this promising tool in the treatment of portal hypertension.

Neural substrates of motor and cognitive dysfunctions in SCA2 patients: A network based statistics analysis

Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant neurodegenerative disease characterized by a progressive cerebellar syndrome, which can be isolated or associated with extracerebellar signs. It has been shown that patients affected by SCA2 present also cognitive impairments and psychiatric symptoms.

The cerebellum is known to modulate cortical activity and to contribute to distinct functional networks related to higher-level functions beyond motor control. It is therefore conceivable that one or more networks, rather than isolated regions, may be dysfunctional in cerebellar degenerative diseases and that an abnormal connectivity within specific cerebello-cortical regions might explain the widespread deficits typically observed in patients.

In the present study, the network-based statistics (NBS) approach was used to assess differences in functional connectivity between specific cerebellar and cerebral “nodes” in SCA2 patients. Altered inter-nodal connectivity was found between more posterior regions in the cerebellum and regions in the cerebral cortex clearly related to cognition and emotion. Furthermore, more anterior cerebellar lobules showed altered inter-nodal connectivity with motor and somatosensory cerebral regions. The present data suggest that in SCA2 a cerebellar dysfunction affects long-distance cerebral regions and that the clinical symptoms may be specifically related with connectivity changes between motor and non-motor cerebello-cortical nodes.

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A cerebellar dysfunction affects long-distance cerebral regions in SCA2 patients.

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Connectivity changes affect sensorimotor and cognitive cerebello-cortical nodes.

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Cerebellar symptoms may be related to altered cerebello-cerebral connectivity.

Gut Microbiota and Alcoholic Liver Disease

The gut-liver axis model has often explained liver disease physiopathology. Among the latter we can mention Non-Alcoholic Liver Steatosis (NAFLD), Liver Steatohepatitis (NASH), liver cirrhosis. In this frame an altered Intestinal Permeability (IP) is the gate for antigenic/toxic substances from gut lumen until target organs such as liver in NAFLD. Altered intestinal permeability was discovered almost forty years ago as consequence of acute and chronic alcohol ingestion. Alcohol Liver Disease (ALD) is a systemic pathology whose beginning and end belong to the intestine. Several recent evidences from the literature show how gut microbiota composition can be altered by alcohol, affects IP and can be modulated by several nonpharmacological and pharmacological agents, becoming the target for ALD treatment. In this review we describe the definition of ALD, gut microbiota composition in healthy and ALD, definition and role of IP in ALD physiopathology and emerging evidences on gut microbiota modulation in ALD treatment from preliminary clinical and non-clinical studies.

Hepatocellular carcinoma in cirrhotic patients with transjugular intrahepatic portosystemic shunt: a retrospective case-control study

BACKGROUND

An association between Transjugular Intrahepatic Porto-Systemic Shunt (TIPS) and the development of hepatocellular carcinoma in patients with cirrhosis has been suggested, but not confirmed.

AIM

To evaluate the potential role of TIPS in hepatocellular carcinoma development.

METHODS

We performed a retrospective case-control study among patients with cirrhosis; all cases had undergone TIPS placement. Cases and controls were followed as outpatients at a single liver care centre in the same timeframe.

RESULTS

Overall, 101 patients with cirrhosis (mean age 58 ± 9 years, 64.3% male) were included in each group. Median duration of follow-up was 56.7 months (range 8.2-174.5) for TIPS patients and 67.8 months (range 8.3-183.1) for controls (p=0.08). In both groups 94% of patients had Child-Pugh Class A or B cirrhosis. The cumulative incidence of hepatocellular carcinoma at 1, 3, 5, and 10 years was 2%, 7%, 18%, and 46% among TIPS patients, and 3%, 10%, 19%, and 39% among controls (log rank test p=0.19). Compared to controls, hepatocellular carcinoma nodules in TIPS patients were more frequently situated in the right lobe (p<0.05).

CONCLUSIONS

TIPS does not seem to increase the risk of hepatocellular carcinoma in patients with Child-Pugh Class A or B cirrhosis; for these patients ultrasound surveillance should not be modified.

Inhaled nitric oxide versus sodium nitroprusside for preoperative evaluation of pulmonary hypertension in heart transplant candidates

OBJECTIVE

The development of pulmonary hypertension before heart transplantation increases the risk for postoperative right ventricular failure. Reversibility of pulmonary vascular resistance (PVR), which indicates the feasibility of heart transplantation, can be tested with the use of intravenous vasodilators, such as sodium nitroprusside (NaNTP) or prostacyclin. However, the drawback of these drugs is the development of systemic hypotension. The aim of this study was to evaluate the safely and feasibility of inhaled nitric oxide (iNO) compared with sodium nitroprusside to test PVR reversibility, while avoiding systemic hypotension.

MATERIALS AND METHODS

We included all patients who were affected by end stage heart failure undergoing evaluation for heart transplantation if they showed elevated PVR > 2.5 Wood units and mean pulmonary arterial pressure (mPAP) >25 mm Hg. The hemodynamic parameters measured by right heart catheterization were: systolic blood pressure (SBP), mPAP, pulmonary capillary wedge pressure, and cardiac index (CI). The following variables were derived: transpulmonary gradient (TPG) and PVR. All patients were tested by both iNO (20-40 ppm) and intravenous NaNTP, at increasing dosages which were titrated based on systemic pressure. We randomly assigned the order of administration of iNO and NaNTP.

RESULTS

The 9 male candidates has an average age of 56 ± 4 years. Seven of the 9 (71%) had postischemic cardiomyopathy, and 2 had idiopathic cardiomyopathy. We observed a reduction of mPAP (32% and 14%), PVR (41% and 32%), TPG (20% and 26%), and SBP (17% and 5%) and an increase of CI with administration of NaNTP and iNO, respectively.

CONCLUSIONS

We observed a reduction in PVR and mPAP with administration of either iNO and NaNTP. A better effect of NaNTP was attributed to reducted post-load of the left ventricle. However, the main advantage of iNO was the absence of systemic hypotension and its selectivity for pulmonary vascular system, as underscored by TPG reduction.

Intestinal permeability in non-alcoholic fatty liver disease: the gut-liver axis

The gut-liver axis model has helped to explain the liver steatosis (NAFLD) and steatohepatitis (NASH) etiopathogenesis. The discovery of a key role for an altered intestinal permeability (IP) in this pathophysioligcal framework has closed the link between gut lumen antigenic/toxic substances and systemic and liver inflammation in NAFLD and obesity, metabolic syndrome. Recent evidence from the literature show how IP can be modulated by several non-pharmacological and pharmacological agents and be the target for future preventive and curative treatment of NAFLD and NASH. In this review we describe the concept of IP, its ultrastructural basis, its role in the NALFD pathophysiology and emerging evidence on non-pharmacological and pharmacological agents able to favourably modulate it.

Sequential treatment with monofluorophosphate and zoledronic acid in osteoporotic rats

OBJECTIVE

Osteoporosis is the consequence of an imbalance in bone remodeling caused by excessive resorption or inappropriate bone formation. This paper proposes a sequential treatment with monofluorophosphate (MFP) and zoledronic acid (Z), together with changes in the calcium content in the diet.

METHOD

Seven-week-old female Sprague Dawley rats were divided into five groups (n = 21 per group): (1) sham-operated rats (Sham); (2) ovariectomized (OVX) rats fed with a normal calcium diet (OVX); (3) OVX rats fed with a normal calcium diet and treated sequentially with monofluorophosphate and zoledronic acid (OVX.G1); (4) OVX rats sequentially fed with a low calcium diet and then a high calcium diet, without treatment (OVX.G2); (5): OVX rats fed with a low calcium diet and then a high calcium diet, treated sequentially with monofluorophosphate and zoledronic acid (OVX.G3).

RESULTS

After 150 days, the OVX.G3 group showed a similar bone volume to that of the Sham group due to an increase in trabecular number. Dual X-ray absorptiometry bone analysis showed an increase of 9.8% compared with OVX rats. Additionally, an increase in the fracture load at the cortical bone and higher fracture load, ultimate load and stiffness in the compression test were found.

CONCLUSION

The sequential treatment with monofluorophosphate and zoledronic acid increases trabecular bone mass, bone mineral density and bone strength.

Interval training in men at risk for insulin resistance

We compared 3 months of eucaloric (12 kcal/kg/wk) steady state aerobic training (AER) to interval training (INT) in men at risk for insulin resistance. Primary outcomes included oral glucose tolerance testing (OGTT) and HOMA-IR 24 h and 72 h after each participants last exercise session. Secondary outcomes were VO2max, anthropometry, and metabolic syndrome expressed as a summed z-score (zMS). We also performed a sub-analysis for participants entering the trial above and below the HOMA-IR study median. Mean (95% CI) AER ( - 12.81 mg/dl; - 24.7, - 1.0) and INT ( - 14.26 mg/dl; - 24.9, - 3.6) significantly improved 24 h OGTT. HOMA-IR did not improve for AER, but did for INT 24 h and 72 h post-exercise. VO2max improved similarly for both groups. Changes in body mass for INT ( - 2.29 kg; - 3.51, - 1.14), AER, ( - 1.32 kg; - 2.62, 0.58)] and percent body fat [INT, - 0.83%; - 1.62, - 0.03), AER ( - 0.17%; - 1.07, 0.06)] were only significant for INT. When examined as a full cohort, zMS improved for both groups. Upon HOMA-IR stratification, only high HOMA-IR AER showed significant improvements, while both low and high INT HOMA-IR participants demonstrated significant reductions (P<0.05). Eucaloric AER and INT appear to affect fasting glucose, OGTT and VO2max similarly, while INT may have a greater impact on HOMA-IR and zMS.

Effect of astaxanthin on cycling time trial performance

We examined the effect of Astaxanthin (AST) on substrate metabolism and cycling time trial (TT) performance by randomly assigning 21 competitive cyclists to 28 d of encapsulated AST (4 mg/d) or placebo (PLA) supplementation. Testing included a VO2max test and on a separate day a 2 h constant intensity pre-exhaustion ride, after a 10 h fast, at 5% below VO2max stimulated onset of 4 mmol/L lactic acid followed 5 min later by a 20 km TT. Analysis included ANOVA and post-hoc testing. Data are Mean (SD) and (95% CI) when expressed as change (pre vs. post). Fourteen participants successfully completed the trial. Overall, we observed significant improvements in 20 km TT performance in the AST group (n=7; -121 s; 95% CI, -185, -53), but not the PLA (n=7; -19 s; 95% CI, -84, 45). The AST group was significantly different vs. PLA (P<0.05). The AST group significantly increased power output (20 W; 95% CI, 1, 38), while the PLA group did not (1.6 W; 95% CI, -17, 20). The mechanism of action for these improvements remains unclear, as we observed no treatment effects for carbohydrate and fat oxidation, or blood indices indicative of fuel mobilization. While AST significantly improved TT performance the mechanism of action explaining this effect remains obscure.

Mathematical model for the homeostasis of alpha-macroglobulins in the rat

Alpha-macroglobulins (AM) are proteins that inactivate proteinases. Sodium monofluorophosphate (MFP) binds to AM and transiently changes AM plasma levels. As a consequence MFP is useful to modify AM homeostasis. A mathematical model to study the homeostasis of AM is proposed in this paper. The model describes changes in plasma concentration of AM, MFP concentration in the gastrointestinal tract, MFP plasma concentration, plasma concentration of AMMFP and includes rate constants of the processes involved in AM homeostasis. Estimation of the rate constants values was achieved using experimental and mathematical resources. The homeostasis of AM after an oral dose of 80 μmol of MFP was analyzed with a simulation tool. Experimental conditions that modify the homeostasis of AM had been simulated and validated using specific drugs that change some parameter of the system. The mathematical model describes accurately the behavior of the biological model. The results allow concluding that the simplifications made did not underestimate the main processes involved in the homeostasis and, also that the assumptions made were correct.

Epidural plus general anesthesia vs general anesthesia alone for elective aortic surgery: effects on gastric electrical activity and serum gastrin secretion

BACKGROUND

The aim of this study was to evaluate differences in electrogastrographic activity and serum gastrin secretion in patients subjected to general anesthesia (GA) vs blended anesthesia (BA = GA plus epidural analgesia) for abdominal aortic surgery.

METHODS

Thirty-four patients (all males: 28 with abdominal aorta aneurysm, 6 with obstructive aorto-iliac disease; mean age: 68+/-7 years) were randomly assigned either to GA (N.=17) or to BA (N.=17) for abdominal aortic surgery. Each patient was evaluated for serum gastrin secretion at the time of electrogastrography (EGG) 24 h before and after surgery, using ambulatory equipment. Gastrin levels were tested under fasting conditions and after a standard meal. EGG shows gastric electrical activity that parallels gastric motor activity.

RESULTS

Before surgery, no significant difference was found for any of the EGG parameters or the serum gastrin integrated value (area under the curve [AUC]) between the two groups of patients. After surgery, an increased frequency of electrical waves (tachygastria) was observed in 22% of those undergoing GA and in 5% of patients undergoing BA. The power ratio (postprandial/fasting total power) was exceedingly high (>4) in 53% of the GA patients and in 11% of the BA patients (P<0.05). The gastrin AUC was 263+/-58 pg/mL in the GA group and 179+/-92 pg/mL in the BA group (P<0.01).

CONCLUSIONS

An excess of EGG activity and serum gastrin secretion was observed in patients undergoing GA vs those submitted to BA. Thus, the latter procedure seems to affect gastric function less than GA alone.

Fluid responsiveness and right ventricular function in cardiac surgical patients. A multicenter study

INTRODUCTION

We investigated fluid responsiveness in a population of patients undergoing coronary artery revascularization, with respect to their right ventricular ejection fraction.

MATERIALS AND METHODS

This was a multicenter trial involving 11 cardiac surgical Institutions and 65 patients undergoing elective coronary artery revascularization. Hemodynamic parameters were measured before and after volume expansion using a modified pulmonary artery catheter and transesophageal echocardiographic monitoring. Patients demonstrating an increase of stroke volume >20% after volume expansion were considered as responders. Volume expansion with 7 ml/kg of plasma expander was performed when required on a clinical basis.

RESULTS

In the overall population, only the change in aortic blood velocity (cut-off 13%) was a predictor of fluid responsiveness. In patients with a reduced (<0.3) right ventricular ejection fraction only the value of mean pulmonary arterial pressure was predictive of fluid responsiveness (cut-off 18 mmHg). Patients with right ventricular ejection fraction ≥0.3 demonstrated three predictors: changes in aortic blood velocity (cut-off 15%), right ventricular end diastolic volume index (cut-off 80 ml/m(2)), and left ventricular end diastolic area index (cut-off 9 cm(2)/m(2)).

CONCLUSIONS

When right ventricular systolic function is depressed, the right ventricle inability to fill the left chambers results in a lack of the left-sided responsiveness predictors. When the right ventricular systolic function is preserved, all the classical fluid responsiveness predictors are confirmed. Right ventricular function is therefore to be always considered when addressing the problem of fluid responsiveness.

Early experience with the minimal extracorporeal circulation system (MECC) during thoracoabdominal aortic aneurysm repair

AIM

The purpose of this report is to describe our early experience with a minimal extracorporeal circulation system (MECC), a compact closed heparin coated system consisting of a centrifugal pump and a membrane oxygenator, during thoracoabdominal aortic aneurysm (TAAA) repair.

METHODS

Between January and December 2002 the MECC system was employed in seven consecutive patients (four TAAA type II, two TAAA type I and one TAAA type III according to the Crawford classification). In all patients distal aortic, selective renal and visceral perfusion was performed with this compact closed heparin coated system consisting of a centrifugal pump and a membrane oxygenator.

RESULTS

The MECC system was used in all cases with no technical malfunctions. Six out seven patients were discharged from the unit. One patient developed paraplegia after TAAA repair and died on the third post-operative day from multi-organ failure. In this case the total spinal ischaemic time was 120 min and the distal aortic perfusion pressure was <50 mmHg. No cardiac, cerebral, renal, hepatic or bleeding complications were recorded in the remaining six patients.

CONCLUSION

Our early experience with MECC during TAAA repair showed that it is feasible for distal aortic spinal and visceral selective perfusion. Further large clinical trials are required to determine the efficacy of this technique.

Thermal reduction of 7H-benz[d,e]anthracen-7-one and related ketones under hydrogen-transfer conditions

In the presence of hydrogen donor solvents and at elevated temperatures, aromatic ketones can be selectively deoxygenated to the corresponding hydroaromatic compounds. The kinetics for reduction of 7H-benz[d,e]anthracen-7-one (benzanthrone, 6) into 7H-benz[d,e]anthracene (benzanthrene, 1) in 9,10-dihydroanthracene (3) solvent has been investigated in detail. The relatively slow hydrogenation of 6 is due to reversibility of the initial hydrogen-transfer step according to a reverse radical disproportionation (RRD). The dynamics could well be rationalized using the energetics of species computed by density functional theory (DFT). The application of hydrogen donors such as 1 as a hydrogen-transfer agent, although favorable in terms of a low benzylic carbon-hydrogen bond dissociation enthalpy, is limited due to the slow self-hydrogenation, which in case of 1 gives 5,6-dihydro-4H-benz[d,e]anthracene (7).

[Clinical approach in hypertensive elderly patients]

Hypertension in the elderly represents a cardiovascular risk factor which increases due to ageing and to the raise of blood pressure (BP) values. The occurrence of hypertension depends on an interaction between genes and environment. An available antihypertensive therapy causes a reduction in the incidence of cardiovascular events. An antihypertensive therapy in the elderly must take into account: in these subjects BP might be spontaneously lower over 30 mmHg in 24 hours; people normally have a postprandial BP reduction; sudden raises or falls of pressure cause cerebral hypoperfusion; some adverse vents of hypertensive drugs worsen their quality of life, not reducing myocardial hypertrophy; possible electrolytic troubles might worsen a congestive heart failure; drastic diets cause a raise in the incidence of colorectal tumours; a high heart rate increases the risk of sudden death; a chronic NSAID intake might cause or aggravate a hypertensive state; a reduction of natrium chlorure and lipides in the diet might cause a BP fall. In short, the BP reduction should be gradual in the hypertensive elderly in order to avoid the occurrence of cardiovascular events, diets should be balanced, rich in fibres and vitamins to avoid colorectal tumours. Besides, NSAID must be used by these patients for a short time and all therapeutic interventions should improve their quality of life.

Carbon monoxide poisoning: potentially preventable cases

The objective of the study was to describe epidemiological and clinical data regarding acute carbon monoxide (CO) poisoning in an urban area of North Italy. 95 consecutive adult patients admitted to Milan and Turin Poisons Control Centres (PCC) for CO poisoning between October 1993 and March 1995 were enrolled into the study. Epidemiological and medical parameters were recorded in a standardised collection data sheet, which included age, sex, circumstances of poisoning, severity grading (0-3), blood HbCO level upon admission.

RESULTS

86 cases of CO poisoning (90.5%) were due to accidental exposures, 9 to intentional suicide attempts. A majority of cases occurred in late autumn through winter months, from October to February. The highest proportion of accidental CO poisoning cases (92%) occurred in the household setting. In 57 cases the acute severity grading was higher than 1 (median 2); blood HbCO level upon admission was 40% in 16% of the cases (mean 31.6%--median 32.7%).

CONCLUSIONS

Carbon monoxide exposure represents a significant cause of severe but potentially preventable accidental poisoning. The study indicates the need for public education campaigns aimed to warn people against the silent killer at home, and to promote preventive measures. The clinical course of CO poisoning is often severe. A standardised collection data system, to record all the cases of acute CO intoxication in Emergency Departments, can help evaluate the real incidence and clinical significance of this poisoning.

Matrix metalloproteinases. Their role in degenerative chronic diseases of abdominal aorta

BACKGROUND

The main chronic degenerative diseases of the abdominal aorta, namely aneurysmatic and steno-obstructive pathologies, have a common denominator: atherosclerosis. Both pathologies are characterised by the destruction of the structural integrity of the extracellular protein matrix (ME). A number of studies have shown the presence and involvement of a group of enzymes with proteolytic activity towards one or more ME components, the matrix metalloproteinases (MMPs), in the pathogenesis of aneurysms of the abdominal aorta. Other authors have underlined the role of MMPs in the proliferation and migration process of smooth muscle cells into the intima in the pathogenesis of atheromasic plaque. The aim of this study was to evaluate the possible role of these enzymes in the pathogenesis of chronic degenerative diseases of the aorta.

METHODS

Fragments of aortic wall were removed from patients undergoing elective aortic surgery for aneurysms (14 patients) or aortic steno-obstruction (4 patients). The samples obtained were treated appropriately and then subject to immunohistochemical analysis. The preparations were incubated with specific anti-MMP antibodies and were also incubated with substrate and chromogen, forming a pigmented precipitate on the site of the antigen, before being observed using an optic microscopic at an enlargement of 250x. Nuclear positivity linked to the presence of the antigen testified the validity of staining. Lastly, the MMP INDEX, or in other words the number of positive cells out of 100, was stained in the adventitia and in the tunica media in each preparation.

RESULTS

MMPs were divided into three main groups: interstitial collagenase (MMP1) which degrade type I and III native collagen; gelatinases (MMP9, MMP2) which act on elastin and type IV collagen; stromelysins (MMP3) with specific proteolytic action towards proteoglycans, fibronectin and laminine. In our experience, those preparations obtained from aorta affected by steno-obstructive pathologies (4 patients) revealed the presence of MMPs with a preferential localisation on the intimal side of the tunica media. In particular, the increased activity of gelatinases MMP9 in atherosclerotic aorta might be responsible for destroying the internal elastic lamina and fostering the proliferation and migration of smooth muscle cells and the formation of atheromasic plaque. On the other hand, preparations obtained from aneurysmatic aorta (14 patients) showed an opposite situation with a preferential localisation within the adventitia and on the adventitial side of the media. Above all, the loss of elastin represents an essential stage in the formation of aortic aneurysms.

CONCLUSIONS

This study concords with numerous authors who have demonstrated the involvement of proteinase MMPs in the development of aortic aneurysms and their possible role in the pathogenesis of atheromasic plaque. The different origin of these enzymes (inflammatory cells and macrophages or endothelial cells) may be the result of different pathogenetic mechanisms. Although they present different pathogenetic features, aortic aneurysms and steno-obstructions have a common denominator in atherosclerosis. The mechanisms responsible for their evolution towards one or other form are not known. The different expression of MMPs in the context of the aortic wall represents a field for future research.

Sleep disturbances in children with atopic dermatitis

OBJECTIVES

To test hypotheses based on clinical impressions that children with atopic dermatitis (AD) have frequent sleep-related problems, including difficulty falling asleep, night waking due to itching and scratching, and daytime symptoms of tiredness and irritability.

DESIGN

Sleep habits and behaviors were assessed using the Child Sleep Behavior Scale (a 22-item Likert-type questionnaire for parents) in children with AD compared with normative data for age. Twelve questions were added to the questionnaire to address sleep-related habits relevant to night time pruritus, and to assess daytime behavioral symptoms of inadequate sleep.

SETTING

Tertiary care center.

PATIENTS

Fifty-nine children between ages 5 and 12 years meeting criteria for AD representing a referral population to a regional center.

RESULTS

Compared with normative data, children with AD showed notable differences for nine of the 22 items on the sleep questionnaire, including the following: greater difficulty falling asleep, frequent night waking, less total sleep, and greater difficulty awakening for school. The children with AD also reported frequent daytime tiredness and irritability, and the severity of AD symptoms showed moderate correlations with sleep problems and with daytime behaviors suggestive of inadequate sleep. Difficulty falling asleep and night waking correlated with daytime behavior and discipline problems.

CONCLUSIONS

Children with AD often have disrupted sleep and daytime behavioral difficulties associated with insufficient sleep. Improved sleep may be an important treatment focus in the clinical management of children with AD.

Serum ferritin levels in celiac disease

Of the various common assayed parameters of iron metabolism, serum ferritin levels are the most discriminatory in distinguishing between non-treated celiac disease and other gastrointestinal disorders in the pediatric age group. Patients on normal diets usually have very low ferritin levels that increase at an average rate of 1 microgram/1/month when placed on a gluten-free diet. When the patient returns to a normal diet, however, ferritin levels decrease rapidly at an average rate of about 4 microgram/1/month. There is a relationship between abnormal intestinal changes and low ferritin levels in celiac disease with improvement in both when the patient is on a gluten-free diet. It is suggested that serial blood ferritin evaluations together with the leukocyte migration inhibition factor production assay should eliminate the need for invasive intestinal biopsies for the confirmation and possible follow-up to response to treatment.

Gene controlling L-glutamic acid decarboxylase synthesis in Escherichia coli K-12

Genetically related Escherichia coli K-12 strains were found to differ widely in their l-glutamic acid decarboxylase (GAD) activity. This variation is due to differences in the amount of GAD produced by the different cultures, rather than to the appearance of altered enzymes differing in catalytic activity. A regulatory gene, gadR, which controls the amount of GAD was mapped on the E. coli K-12 chromosome. A strain with a lesion in the structural gene for GAD is described.

Glutamate transport in wild-type and mutant strains of Escherichia coli

Halpern, Yeheskel S. (Hebrew University-Hadassah Medical School, Jerusalem, Israel), and Meir Lupo. Glutamate transport in wild-type and mutant strains of Escherichia coli. J. Bacteriol. 90:1288-1295. 1965.-Mutants of Escherichia coli able to grow on glutamate as their source of carbon showed glutamate dehydrogenase and glutamate-oxaloacetate transaminase activities similar to those possessed by the parent strain. The mutants took up glutamate at a much faster rate and showed a several-fold greater capacity for concentrating the amino acid than did the corresponding parent strains. Curvilinear double reciprocal plots of velocity of uptake versus glutamate concentration were obtained with the E. coli H strains. A break in the curve of glutamate uptake was observed with the E. coli K-12 strains when incubated in a glucose medium. It is suggested that these findings may be due to allosteric activation of glutamate permease by its substrate.