Epi-illumination fluorescent light microscopy for the in vivo study of rat hepatic microvascular response to cryothermia

To elucidate the hepatic microvascular response to cryothermia, we studied the liver microcirculation of Sprague-Dawley rats after one and two 4-minute freeze-thaw cycles using intravital fluorescence microscopy. Irrespective of the number of freeze-thaw cycles applied, the nature of hepatic microvascular injury was characterized by complete stasis of sinusoidal blood flow within the central part of the cryolesions and heterogeneous sinusoidal perfusion in a critically perfused border zone located at the periphery of the lesions. Analysis over time (2 hours) revealed a successive shutdown of sinusoidal perfusion within this critically perfused border zone, which was caused by intravascularly lodging cell aggregates, blocking the lumen of individual sinusoids. The aggregates consisted of parenchymal cells and cell fragments, but did not include leukocytes or platelets. Strikingly, microvascular perfusion failure was associated with Ito cell disintegration and marked dilation of sinusoids (15.6 +/- 0.8 microm vs. 8.8 +/- 0.8 microm; P <.05). This excludes sinusoidal constriction as the cause of nutritive perfusion failure, and may indicate dysfunction of Ito cell-regulated vasomotor control by cryothermia. However, because circulating cell aggregates were frequently observed plugging individual microvessels, dilation of sinusoids may just be the result of passive distension caused by outflow blockade. Analysis of hepatic tissue at 8 weeks after cryothermia did not reveal regeneration and microvascular remodeling, but loss of hepatic tissue, which corresponded well with the tissue area presenting with sinusoidal perfusion failure during the initial observation period after cryothermia. The fact that there was no recovery of sinusoidal perfusion over the initial 2-hour observation period, but loss of tissue after 8 weeks, supports the view that cryothermia induces injury not only by direct low-temperature-mediated action, but also through ischemia caused by irreversible deterioration of the microcirculation.     

Functional limitations in children and adolescents suffering from chronic pain: validation and psychometric properties of the German Functional Disability Inventory (FDI-G)

Our objective was to translate the Functional Disability Inventory (FDI) into German, to evaluate its validity and to assess functional limitation in a large cohort of children and adolescents with juvenile fibromyalgia syndrome (jFMS). We administered several questions (e.g., sociodemographics, school-related issues) and questionnaires to 329 patients and one parent. The questionnaires included, among others, a German version of the FDI, the CHAQ (parent report), KIDSCREEN, tender point score (TPS), Depression Inventory for Children and Adolescents (DIKJ) and others. Patients were asked about the severity of pain today (NRS = numerical rating scale) and other symptoms. Internal consistency was evaluated with Cronbach’s alpha. Construct validity of the FDI was evaluated by correlating the FDI with the questionnaires as well as with the pain and other variables, e.g., days missed school. An exploratory factor analysis (EFA) was also performed. Mean age was 13.9 years (SD ±2.48). Means were for pain today 5.37 (±2.39) and for the TPS 39.71 (±21.56). Internal consistency was α = .90. Low-to-moderate correlations were obtained between the FDI and the CHAQ (ρ = .51**), KIDSCREEN (e.g., physical well-being ρ = ?.62**; peers and social support ρ = ?.28**) as well as the pain variables (NRS ρ = .24**; TPS ρ = .38**). Psychological variables were also correlated with the FDI (e.g., DIJK ρ = .28**). An EFA suggested a two-factor solution. The FDI is a valid instrument for measuring functional limitations in German children and adolescents with jFMS.     

Characterizing left ventricular mechanical and electrical activation in patients with normal and impaired systolic function using a non-fluoroscopic cardiovascular navigation system

Purpose

Cardiac disease frequently has a degenerative effect on cardiac pump function and regional myocardial contraction. Therefore, an accurate assessment of regional wall motion is a measure of the extent and severity of the disease. We sought to further validate an intra-operative, sensor-based technology for measuring wall motion and strain by characterizing left ventricular (LV) mechanical and electrical activation patterns in patients with normal (NSF) and impaired systolic function (ISF).

Methods

NSF (n?=?10; ejection fraction?=?62.9?±?6.1%) and ISF (n?=?18; ejection fraction?=?35.1?±?13.6%) patients underwent simultaneous electrical and motion mapping of the LV endocardium using electroanatomical mapping and navigational systems (EnSite? NavX? and MediGuide?, Abbott). Motion trajectories, strain profiles, and activation times were calculated over the six standard LV walls.

Results

NSF patients had significantly greater motion and systolic strains across all LV walls than ISF patients. LV walls with low-voltage areas showed less motion and systolic strain than walls with normal voltage. LV electrical dyssynchrony was significantly smaller in NSF and ISF patients with narrow-QRS complexes than ISF patients with wide-QRS complexes, but mechanical dyssynchrony was larger in all ISF patients than NSF patients. The latest mechanical activation was most often the lateral/posterior walls in NSF and wide-QRS ISF patients but varied in narrow-QRS ISF patients.

Conclusions

This intra-operative technique can be used to characterize LV wall motion and strain in patients with impaired systolic function. This technique may be utilized clinically to provide individually tailored LV lead positioning at the region of latest mechanical activation for patients undergoing cardiac resynchronization therapy.

Clinical trial registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01629160.

     

Cyclic motility in canine colon: Responses to feeding and perfusion

To further characterize colonic motility in the dog and to examine the effects of intraluminal contents, motor activity in conscious animals was recorded by perfused intraluminal catheters. Animals were studied first with the bowel intact and, later, the colon was fashioned into an isolated loop. In the fasting state, cycles of motility recurred approximately each 30 min. These consisted of sequences of phasic contractions (bursts) that migrated variable distances in either direction; stationary bursts were also recorded. The fasting patterns recorded from intact bowel and isolated loops were not different. Feeding increased colonic motility, and the mean periodicity of cyclic bursts was reduced significantly to approximately 20 min. Moreover, differences were observed between intact bowel and isolated loops in the postprandial period. Diversion of chyme from the colon significantly reduced the motor response to food, but only in the late (2– 4 hr) postprandial period, when the less frequent, fasting cycle returned to the loops. Perfusion of isolated loops with chyme or saline reestablished the postprandial pattern seen in intact bowel. The results suggest that the volume, but not the composition, of luminal contents modify postprandial motility in the canine colon. Additional experiments confirmed that, in particular, volatile fatty acids were probably not important determinants of colonic motility in the dog.Supported in part by grants AM 32121, AM 34988, and RR 585 from the National Institutes of Health, Bethesda, Maryland.Dr. Flourie was supported in part by grants from the French Government and the Fondation pour la Recherche Medicale.     

Antibakterielle Aktivität von Clindamycin und Linkomycin in Bouillon,Serum und in Kombination mit Polymorphkernigen Granulozyten gegen Staphylococcus aureus und Staphylococcus epidermidis

Zusammenfassung Wir untersuchten die antibakterielle Aktivität von Clindamycin und Linkomycin bei 1/4 × minimaler Hemmkonzentration (=MHK), 1 × MHK und 4 × MHK gegen einen serumresistentenStaphylococcus aureus- und einen serumresistentenStaphylococcus epidermidis-Stamm in Bouillon, in Serum mit und ohne Gegenwart von Leukozyten bzw. in Hank's Medium mit Leukozyten allein. Linkomycin war gegen beide Teststämme in Bouillon und Serum gleichermaßen wirksam, während Clindamycin in Bouillon gegenS. aureus doch etwas aktiver war. Im kombinierten Ansatz von Serum mit Leukozyten verbesserte bereits 1/4 × MHK von Clindamycin bzw. Linkomycin deutlich die leukozytäre Abtötung vonS. aureus, während beiS. epidermidis beide Substanzen die hohe leukozytäre Abtötungsrate auch bei inhibitorischen Konzentrationen nicht weiter verbessern konnten. In Hank's Medium mit Leukozyten allein hatten Clindamycin wie Linkomycin gegen beide Teststämme maximal nur einen bakteriostatischen Effekt.

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Antibacterial activity of clindamycin and lincomycin in broth, serum and in combination with polymorphonuclear leukocytes against staphylococcus aureus and staphylococcus epidermidis

Summary We investigated the antibacterial activity of clindamycin and lincomycin at 1/4×minimum inhibitory concentration (MIC), 1 × MIC and 4 × MIC against a serum-resistantStaphylococcus aureus and a serum-resistantStaphylococcus epidermidis strain in broth, in serum with and without the presence of leukocytes and in Hank's medium in combination with leukocytes alone. Against both test strains, lincomycin in broth and serum was similiarly effective, whereas againstS. aureus clindamycin in broth was somewhat more active. In the combined test mixture of serum with leukocytes, even a 1/4 × MIC of clindamycin or lincomycin markedly improved leukocyte killing ofS. aureus, whereas both compounds could not further enhance the marked leukocyte killing ofS. epidermidis, even at inhibitory concentrations. In Hank's medium with leukocytes alone, clindamycin and lincomycin had at the most only a bacteriostatic effect against both test strains.

     

Epitope spreading and a varying but not disease-specific GAD65 antibody response in Type I diabetes

Aims/hypothesis. The aim of this study was to analyse the conformational and linear epitope profiles of glutamic acid decarboxylase antibody (GAD65-ab)-positive sera to find disease-specific epitope profiles and to study, whether GAD65-ab epitope recognition changes or spreads during the prediabetic period and, thus, can provide markers to differentiate early from later stages of progression to diabetes.¶Methods. Sera from subjects before (n = 21), at onset (n = 44), or at increased risk of Type I (insulin-dependent) diabetes mellitus (n = 20) and from patients with stiff-man syndrome (SMS, n = 18) or polyendocrine autoimmune syndrome (PAS, n = 21) were analysed for conformational and linear GAD65 epitope recognition by an immunohistochemical blocking test based on human monoclonal GAD65-ab (MICA 1–10) and western blotting of a GAD65 epitope-cDNA-library.¶Results. A redundant reactivity of many GAD65-ab positive sera to three major conformational (EP-1, EP-2, EP-3) and two dominant linear epitope clusters (amino acid 1–124 and 535–585) was observed in diabetes, polyendocrine autoimmune syndrome and stiff-man syndrome and no disease-specific epitopes or epitope-profiles were detected. Epitope recognition broadened with higher titres and with the vulnerability of patients to acquire additional autoimmune diseases apart from diabetes. Low GAD65-ab serum titres ( < 1200 arbitrary units) and EP-1 recognition in the absence of EP-2 binding characterised the early immune response. Changing epitope profiles combined stable recognition of EP-1 with gain or loss of reactivity to C-terminal epitopes during follow-up.¶Conclusion/interpretation. A maturing autoantibody response, which could spread from EP-1-recognition to other regions of GAD65, resulted in titre-related rather than disease-specific epitope profiles which were not sufficient to predict whether GAD65-ab positive subjects will progress to Type I diabetes, autoimmune polyendocrine syndrome or stiff-man syndrome. [Diabetologia (2000) 43: 210–217]