Single versus double experimental bile duct ligation model for inducing bacterial translocation.

BACKGROUND: Double common bile duct ligation plus section in rats is used as a model for bacterial translocation, a phenomenon that has been correlated with the degree of liver damage. This study analyzes whether a simpler variant of the technique is also a valid model to study bacterial translocation. METHODS: Fifty-six male Sprague Dawley rats underwent one of three surgical interventions: a) proximal double ligation and section of the common bile duct; b) proximal simple ligation of the bile duct; and c) sham operation. Bacterial translocation was measured by cultures of mesenteric lymph nodes, blood, spleen and liver. Stool culture and histological analysis of liver damage were also performed. RESULTS: The incidence of bacterial translocation in SBL and DBDL groups was 23,5% and 25% respectively. Mortality was similar between ligation groups (11.2% versus 10%). Liver cirrhosis developed in the group of double ligation and section (100% of the animals at 4 weeks), while portal hypertension appeared starting at week 3. None of the animals submitted to simple ligation developed liver cirrhosis. CONCLUSIONS: Simple bile duct ligation is associated with a similar incidence of bacterial translocation as double ligation, but without cirrhosis or portal hypertension.

Initial performance evaluation of a preclinical PET scanner available as a clip-on assembly in a sequential PET/MRI system.

We evaluated the performance characteristics of a prototype preclinical PET scanner available as an easy clippable assembly that can dock to an MRI system. The single ring version of the PET system consists of eight detectors, each of which comprises a 12 × 12 silicon photomultipliers (SiPMs) array coupled with a dual layer of offset scintillation crystals to measure depth of interaction. The crystal arrays have 29 × 29 (30 × 30 for the outer layer) 4 mm long LYSO crystals (6 mm for the outer layer). The ring diameter is 119.2 mm and the axial field of view is 50.4 mm. The NEMA NU 4-2008 protocol was followed for studying the PET performance. Temperature stability of SiPMs was also investigated. The peak system absolute sensitivity was 4.70% with an energy window of 250-750 keV. The spatial resolution was 1.28/1.88/1.85 mm FWHM (radial/tangential/axial) at a distance of 5 mm from the center. Peak noise equivalent counting rate and scatter fraction for mouse phantom were 61.9 kcps at 14.9 MBq and 21.0%, respectively. The uniformity was 6.3% and the spill-over ratios in the images of the water-and air-filled chambers were 0.07 and 0.17, respectively. Recovery coefficients ranged from 0.13 to 0.96. Change in sensitivity as a function of ambient temperature was 0.3%/°C. These first results indicate excellent spatial resolution performance for use with animal studies. Moreover, the clippable assembly can be upgraded to accept a second ring of SiPMs modules, leading to improved sensitivity and axial coverage.

Machine perfusion: initial results in an expanded criteria donor kidney transplant program.

BACKGROUND: Delayed graft function (DGF) negatively impacts graft survival. Expanded criteria donors (ECD) show a higher rate of DGF. Hypothermic machine perfusion (HMP) has shown a DGF decrease and an increase of survival at 1 year. Several authors found that renal resistance (RR) at the end of machine perfusion was an independent risk factor for the development of DGF and poorer graft survival. The objective of this study was to analyze HMP results in the context of an ECD program and assess the impact of donor parameters and resistance index (RI) during perfusion in graft survival after kidney transplantation. METHODS: Donor age, terminal creatinine, machine perfusion time, percentage of glomerulosclerosis, and RI at the end of the perfusion were considered as risk predictors. Univariate and multivariate Cox regression analysis was constructed to find independent risk factors of DGF. Finally, diagnostic validity for RR was determined by sensitivity, specificity, and positive and negative predictive values. RESULTS: Twenty-three percent of patients developed DGF. We found no difference in the ability of flow or RI to predict the development of DGF. The predictive accuracy of RI for DGF by receiver operator characteristic curve was poor, with a c-statistic of 0.66 (95% CI, 0.50-0.81; P = .046). Our analysis did not identify risk factors that predicted graft survival at 1 year. Patient and graft survival were 98.8% and 89.7%, respectively. CONCLUSIONS: HMP has reduced the rate of DGF in our cohort of recipients of ECD grafts compared with historical data (23.3% vs 38.0%). Analysis did not identify risk pretransplant factors for graft survival at 1 year.

Development of urologic de novo malignancies after renal transplantation.

OBJECTIVES: The incidence of neoplasms in renal transplant recipients is higher than in general population. The increasing age of donors and recipients also increases the risk of developing malignancies, including genitourinary. The aim of this study is to analyze clinical aspects and management of this complication. MATERIALS AND METHODS: We conducted a retrospective analysis of 1365 patients who underwent renal transplantation between 1977 and 2010 who were 44.6 ± 14.9 years old at the time of transplantation. The median follow-up was 95.6 months (range, 18.0-236.0). Data were analyzed for sex, age, time from transplant to diagnosis, location, clinical stage, immunosuppression, treatment, follow-up, and evolution. RESULTS: We diagnosed 25 de novo urologic neoplasms (25/1365; 1.8%) in 24 patients, with a median follow-up of 32 months (range, 12.5-51.8) from the diagnosis. Sixteen were male (66.7%) and 8 female (33.3%), with a median age at diagnosis of 59 years (range, 56.0-65.5). The median time between the transplant and the diagnosis of the malignancy was 69 months (range, 40.0-116.5). There were 11 renal cell carcinomas (RCC; 11/25; 44%), 8 in native kidney and 3 in renal allograft; 9 prostate cancers (PCa; 9/25; 36%), 8 localized and 1 metastatic; and 5 transitional cell carcinomas (TCC; 5/25; 20%), 3 in bladder and 2 in renal allograft pelvis. Treatments performed were similar to those used in the nontransplanted population. RCC were treated with radical nephrectomy when affecting the native kidney, partial nephrectomy when affecting the allograft, or immunotherapy when metastatic. Patients with localized PCa were treated with radical prostatectomy, radiotherapy, or androgenic deprivation if there were comorbidities, and those metastatic with hormonal deprivation. Bladder TCCs were treated with transurethral resection or radical cystectomy. Pelvis TCCs affecting the allograft were treated with radical nephroureterectomy of the allograft including bladder cuff and pelvic lymphadenectomy. CONCLUSIONS: There exists an increased incidence of urologic tumors in kidney transplant recipients. Conventional treatments of these tumors are technically feasible. The risk of developing these tumors remains even in the long term. Because of their suitability for curative treatments, it is advisable to perform periodic screening for urologic cancers to achieve an early diagnosis.

Blockade of nociceptive sensory afferent activity of the rat knee joint by the bradykinin B2 receptor antagonist fasitibant.

OBJECTIVE: The aim of this study was to determine in intact and inflamed knee joints of the rat, the effect of the bradykinin (BK) B2 receptor antagonist fasitibant (MEN16132) on nociceptor mechanosensitivity and hyperalgesia. METHODS: Joint afferent sensory fibers of the medial articular nerve of anesthetized animals were electrophysiologically recorded, measuring nerve impulse activity evoked by passive innocuous and noxious movements of the joint, in intact and kaolin and carrageenan-injected joints. Knee joints of rats were also acutely inflamed by intra-articular injection of carrageenan alone. Long term duration of fasitibant antinociceptive effects were behaviorally evaluated using the incapacitance test. RESULTS: BK (100 µM) injected into the saphenous artery, induced excitation and sensitization of multi- and single unit recordings. Fasitibant (300 µM) injected prior to BK, reduced its excitatory effects as well as the overall increase of movement-evoked activity resulting from repeated injections of BK. Fasitibant did not affect movement-evoked activity of sensory fibers of intact, non-inflamed knee joints. Intra-articular fasitibant (100 µg/knee) significantly reduced the carrageenan-induced inflammatory hyperalgesia measured with the incapacitance test up to four days after treatment. This antinociceptive effect was not obtained with systemic endovenous injection of the drug. CONCLUSIONS: Fasitibant prevents B2 receptor-mediated activation and sensitization of peripheral joint afferents and the ensuing inflammatory hyperalgesia, and may be a useful, novel drug for arthritis pain treatment.

Candiduria in renal transplant recipients: incidence, clinical repercussion, and treatment indication.

INTRODUCTION: The incidence of candiduria in renal transplant recipients is unknown. In clinical practice, the indications for antifungal therapy are not well established. Furthermore, there is the problem of the choice of the antifungal drug since some of them may select resistant Candida species, or interact with immunosuppressive agents or only be used intravenously. AIM: We sought to study the incidence, clinical repercussions and effectiveness of antifungal treatment to prevent recurrence of candiduria. MATERIALS AND METHODS: We examined all episodes of Candida-positive urine cultures (>50,000 cfu/mL) in 996 recipients over 2 years. We considered the Candida species, administered treatment, presence of fever, requirement for hospital admission versus outpatient case, occurrence of simultaneous bacterial urinary tract infection (UTI), antibiotic use during the week before candiduria, and presence of an indwelling urinary catheter. RESULTS: Among 996 subjects, 34 displayed 83 episodes of candiduria, yielding an accumulated incidence of 3.4% after 2 years. The frequency was higher among women (6.3% vs 1.7%, P<.001). Of the 45 outpatient episodes (54.2%), 17 were treated and one required hospitalization (5.9%). Of the 28 nontreated outpatients, two were hospitalized (7.1%, P=.68 vs treated patients). All cases of hospital admission presented simultaneous bacterial UTI, none developed candidemia, and two patients did not receive any antifungal therapy. With respect to the first episodes of each patient (n=34), 5/11 treated (45.5%) and 4/23 untreated (17.4%) patients developed recurrences (P=.095). Selection of more resistant Candida species was not observed. Fifty cases (60%) were associated with antibiotic therapy and 34 (41%) the presence of a urinary catheter. CONCLUSIONS: It does not seem necessary to treat candiduria in this setting. Antifungal therapy was not associated with either a reduction in recurrence or the appearance of more resistant species in this study. We observed no important clinical repercussions.

Intra-articular injections of hyaluronan solutions of different elastoviscosity reduce nociceptive nerve activity in a model of osteoarthritic knee joint of the guinea pig.

OBJECTIVE: To study in guinea pigs knee joints the effects of intra-articular injection of HYADD 4-G (Fidia-Farmaceutici), a novel hyaluronan (HA)-derived elastoviscous material and of Hyalgan (Fidia-Farmaceutici), a HA product with very low viscoelasticity, on movement-evoked nociceptor impulse activity from normal and inflamed knee joints. DESIGN: Nociceptor impulse activity was recorded from single Adelta and C fibers of the medial articular nerve either under control conditions or after induction of an experimental knee joint osteoarthritis (OA) by partial medial menisectomy and transection of the anterior cruciate ligament (PMM-TACL). The stimuli consisted of standardized innocuous and noxious inward and outward rotations of the tibia against the femur of 50s duration, repeated every 5min for 1.5h. RESULTS: The number of movement-evoked impulses was significantly augmented 1 day and 1 week after PMM-TACL compared with intact knee joint. The enhanced impulse response to joint movements 1 week following surgery was attenuated by repeated intra-articular injection of HYADD 4-G and even more prominently by Hyalgan. CONCLUSIONS: HA products have a reducing action on joint nociceptor discharges that appears to depend predominantly on their role as an elastoviscous filter associated with their rheological properties, but also on a chemical effect on sensitized nociceptive terminals of inflamed joint tissues, possibly linked to the HA concentration.

Las cartillas farmacéuticas publicadas en España en el siglo XVIII / Pharmaceutical Science in Spain in the 18th century: a critical appraisal of the 18th Century pharmaceutical handbooks known as “Cartillas”

Luego de señalarse las principales características que tenía la formación de los boticarios en la España del siglo XVIII, se expone, en este trabajo, la aparición de una serie de Cartillas farmacéuticas que se publicaron con el objeto de lograr una mejor formación teórica en el aprendiz. Se analiza, con detalle, la estructura y calidad de los contenidos que tuvieron las Cartillas farmacéuticas que publicaron, a lo largo del siglo, Pedro Montañana, Pedro de Viñaburu y Francisco Brihuega

After describing the main characteristics involved in the training of chemists in Spain during the 18th Century, this work discusses the appearance of a series of Pharmaceutical handbooks (Short Treatises), which were published as a means to improving theoretical training. In this work, a critical analysis of the structure and quality of the contents of publications written by Pedro Montañana, Pedro de Viñaburu and Francisco Brihuega published throughout the century has been carried out

Calcium influx selects the fast mode of endocytosis in the synaptic terminal of retinal bipolar cells.

To investigate the regulation of endocytosis by Ca(2+), we have made capacitance measurements in the synaptic terminal of depolarizing bipolar cells from the retina of goldfish. After a brief depolarization, all of the excess membrane was retrieved rapidly (tau approximately 1 s). But when the rise in free [Ca(2+)] was reduced by the introduction of Ca(2+) buffers [1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetate (BAPTA) or EGTA], a large fraction of the membrane was retrieved by a second, slower mechanism (tau > or = 10 s). The block of fast endocytosis by EGTA could be overcome by increasing the amplitude of the Ca(2+) current, demonstrating that Ca(2+) influx was the trigger for fast endocytosis. These manipulations of the Ca(2+) signal altered the relative proportions of fast and slow endocytosis but did not modulate the rate constants of these processes. A brief stimulus that triggered fast endocytosis did not generate a significant rise in the spatially averaged [Ca(2+)], indicating that Ca(2+) regulated endocytosis through an action close to the active zone. The slow mode of retrieval occurred at the resting [Ca(2+)]. These results demonstrate that Ca(2+) influx couples fast endocytosis and exocytosis at this synapse.

Studies on cellulitis and other disease syndromes caused by Escherichia coli in broilers in Sri Lanka.

Cellulitis caused by Escherichia coli in broilers results in substantial losses to the broiler industry in North America and Europe due to condemnations at slaughter. The objective of this study was to identify cellulitis in broilers in Sri Lanka and to characterize the E. coli from cellulitis and other colibacillosis lesions. Twenty-four farms from the low- and mid-country were selected and bacterial isolations were obtained from 241 birds. Two hundred and ninety-one gross lesions were observed in these 241 birds and 162 E. coli isolates were obtained. Cellulitis was observed in 21% of the birds. Twenty-one per cent of the birds had multiple lesions due to E. coli. The frequency of detection of other disease syndromes was 162 (67%) birds with pericarditis, 26 (11%) airsacculitis, 24 (10%) hepatitis, 12 (5%) perihepatitis, and 16 (7%) polyserositis (a combination of pericarditis, perihepatitis and airsacculitis). Serogroups O78, O2, O85 and O88 were distributed among the 32% of typable E. coli and 81% of isolates were assigned to three biotypes. Forty-four per cent of the E. coli isolates produced aerobactin and 88% demonstrated resistance to the bactericidal effect of normal chicken serum. The majority of the E. coli isolates were resistant to the antibiotics commonly used in poultry. All the E. coli isolates were non-haemolytic and 25% of the isolates produced K1 capsule. This study demonstrated the presence of cellulitis in Sri Lanka and this report describes some of the phenotypic characteristics of the E. coli isolates.

Two actions of calcium regulate the supply of releasable vesicles at the ribbon synapse of retinal bipolar cells.

Ribbon synapses of sensory neurons are able to sustain high rates of exocytosis in response to maintained depolarization, but it is not known how this is achieved. Using the capacitance technique, we have found that Ca(2+) regulates the supply of releasable vesicles at the ribbon synapse of depolarizing bipolar cells from the retina of goldfish. Ca(2+) had two actions that could be differentiated by introduction of the Ca(2+) chelator EGTA; one action stimulated refilling of the rapidly releasable pool of vesicles from a reserve pool, and a second action stimulated recruitment of vesicles to the reserve pool. The capacity of the reserve pool was approximately 3500 vesicles, which is similar to the number that can attach to the ribbons. These results suggest that continuous exocytosis at ribbon synapses is maintained by the Ca(2+)-dependent translocation of vesicles from the cytoplasm, through the ribbon, to release sites on the plasma membrane.

Regulation by tolbutamide and diazoxide of the electrical activity in mouse pancreatic beta-cells recorded in vivo.

1. The glucose-dependence of beta-cell electrical activity and the effects of tolbutamide and diazoxide were studied in anaesthetized mice. 2. In untreated animals there was a direct relationship between glycaemia and the burst pattern of electrical activity. Animals with high glucose concentration showed continuous electrical activity. The application of insulin led to a steady decrease in blood glucose concentration and a transition from continuous to oscillatory activity at 7.7+/-0.1 mM glucose (mean+/-s.d.) and a subsequent transition from oscillatory to silent at 4.7+/-0.6 mM glucose. 3. At physiological blood glucose concentrations the electrical activity was oscillatory. The injection of tolbutamide (1800 mg kg[-1]) transformed this oscillatory pattern into one of continuous electrical activity. The increased electrical activity was associated with a decrease in blood glucose concentration from 7.1+/-0.9 (control) to 5.5+/-1.0 mM (10 min after tolbutamide injection). The effects of tolbutamide are consistent with a direct blocking effect on the K(ATP) channel that leads to membrane depolarization. 4. The injection of diazoxide (6000 mg kg[-1]) hyperpolarized the cells and transformed the oscillatory pattern into a silent one. This is consistent with a direct stimulant effect by diazoxide on the K(ATP) channel. The use of tolbutamide or diazoxide correspondingly led to the lengthening or shortening of the active phase of electrical activity, respectively. This indicates that in vivo, such activity can be modulated by the relative degree of activation or inhibition of the K(ATP) channel. 5. These results indicate that under physiological conditions, tolbutamide and diazoxide have direct and opposite effects on the electrical activity of pancreatic beta-cells, most likely through their action on K(ATP) channels. This is consistent with previous work carried out on in vitro models and explains the drugs hypo- and hyperglycaemic effects.

Continuous vesicle cycling in the synaptic terminal of retinal bipolar cells.

Endocytosis and exocytosis were investigated in the synaptic terminal of retinal bipolar cells by monitoring the uptake and loss of the fluorescent dye FM1-43. Depolarization in the presence of Ca2+ stimulated a continuous cycle of exocytosis and endocytosis that was approximately balanced at rates up to 3800 vesicles per s. Vesicles became available for exocytosis within 1 min of endocytosis, and about 700,000 releasable vesicles were specifically localized to a region within 2 microm of the plasma membrane. Release of caged Ca2+ using NP-EGTA while simultaneously monitoring cytosolic Ca2+ with Fura-2 indicated that continuous exocytosis was stimulated by sub-micromolar levels of Ca2+. It has been suggested that the ribbon synapse of bipolar cells only supports transient exocytosis, but our results demonstrate that this synapse is specialized for the continuous secretion of neurotransmitter.

Oscillatory patterns of electrical activity in mouse pancreatic islets of Langerhans recorded in vivo.

Pancreatic beta-cells secrete insulin as a function of blood glucose concentration. One of the key steps in stimulus-secretion coupling is the depolarisation of the membrane and the appearance of bursts of calcium action potentials. Recently, the characteristics and glucose dependence of the oscillations in electrical activity in vivo have been described. The experiments described here were designed to determine the temporal evolution of such electrical activity when no experimental changes in the glycaemia are imposed. The absolute duration of the active and silent phases has been analysed and compared with the values obtained in vitro. We have found that in vivo, at glycaemia ranging from 6.0 to 7.5 mM, the electrical activity of the islets of Langerhans is permanently oscillatory, the mean duration of the depolarisation phase being 28 s. In general, the oscillatory pattern remains very constant for relatively long (up to 60 min) periods of time. In some experiments, slow or transitory changes in the degree of beta-cell activation could be observed, as well as the existence, in a very few cases, of oscillatory non-periodic patterns. Key words beta-cells middle dot Pancreas middle dot Electrophysiology middle dot Oscillations

In vivo synchronous membrane potential oscillations in mouse pancreatic beta-cells: lack of co-ordination between islets.

1. The properties of the oscillations in electrical activity of different beta-cells within the same islet of Langerhans, and of different islets within the same pancreas, recorded in vivo, are described. 2. Simultaneous recordings of two cells within the same islet showed that the oscillations were synchronous. A rapid increase in blood glucose led to the simultaneous appearance of a transitory phase of continuous electrical activity in both cells. These results indicate that under physiological conditions, the islets operate as a functional syncytium. 3. Simultaneous recordings of cells from two different islets within the same pancreas showed that the oscillations in the electrical activity were not synchronous, which suggests that each islet is a functionally independent unit. Rapid changes in blood glucose led to the appearance of a transitory phase of increased electrical activity in both islets, although of different duration. These results suggest that the endocrine pancreas lacks a pacemaker driving the electrical activity of all the islets. 4. The comparison of the degree of activation of different islets, simultaneously recorded at different glucose concentrations, indicated that all the islets had a similar sensitivity to glucose. Furthermore, when the glucose concentration was increased, the electrical activity in both islets increased in parallel, suggesting that the amount of insulin released due to the increase in glycaemia was produced by the simultaneous response of all the islets and not by the recruitment of islets with different sensitivities to glucose. 5. Our results predict that the synchronous electrical activity of all the cells within an islet will result in widespread intracellular calcium oscillations and pulsatile insulin secretion. The periodicity of the pulses of insulin secretion in different islets is suggested to be of slightly different length and asynchronous.

The electrical activity of mouse pancreatic beta-cells recorded in vivo shows glucose-dependent oscillations.

1. The characteristics of the electrical activity of beta-cells from islets of Langerhans recorded in vivo are described. For blood glucose concentrations from 4 to 11 mM, the electrical activity of pancreatic beta-cells is oscillatory, with alternating depolarized and hyperpolarized phases. During the depolarized phases, action potentials are triggered. 2. The main effect of increasing glucose concentration consists of an increase in the duration of the depolarized phase. The relationship between blood glucose concentration and the percentage of time in the depolarized phase can be described by a sigmoidal function with half-activation at 6.8 mM glucose. The equivalent value obtained in parallel experiments in vitro is 13.3 mM, a significant rightward shift in the activation curve that suggests a role for other neural or humoral factors in determining the islet sensitivity to glucose. 3. The injection of glucose into the bloodstream produces a transitory phase of continuous electrical activity that is recorded within seconds after the change and that leads to a decrease of the glycaemia to the prestimulatory value. 4. The results demonstrate that under physiological conditions the electrical response of beta-cells to glucose consists of membrane potential oscillations, validating previous data obtained with isolated preparations. Furthermore, the electrical response occurs at lower levels of glycaemia than those predicted from recordings in isolated preparations and is maximal within the physiological range of blood glucose.