AN ATTRIBUTION OF CAVITATION RESONANCE： VOLUMETRIC OSCILLATIONS OF CLOUD

In order to further verify the proposed theory of cavitation resonance, as well as to proceed the investigations into microscopic level, a series of studies are being carried out on the Warwick venturi. The analysis of the oscillation characteristics of the cavitation resonance has conclusively verified the macro-mechanism proposed through previous studies on other cavitating flows by the authors. The initial observations using high-speed photographic approach have revealed a new attribution of cavitation resonance. That is, the volumetric oscillation of cavitation cloud is associated with the cavitation resonance, which is a collective behaviour of the bubbles in the cloud.     

Focal cerebral ischemia in the mouse: description of a model and effects of permanent and temporary occlusion

Our study is to demonstrate the advantages and disadvantages of middle cerebral artery occlusion (MCAO) model in the mouse. CD-1 mice had permanent MCAO for 24 h, or temporary occlusion for either 1 h followed by 23 h of reperfusion or 2 h of occlusion with 22 h of reperfusion. The infarct volume and blood-brain barrier disruption were smaller in the 1-h/23-h temporary occlusion than in either the 24-h permanent occlusion group or the 2-h/22-h temporary occlusion group (p<0.05). Our study demonstrates that blood flow, infarct volume, and blood-brain barrier disruption remain important markers of focal cerebral ischemia.     

Long-term outcome after sagittal synostosis operations

PURPOSE: Optimization of image quality by use of digital luminescence radiography (DLR) in voiding cystoureterography (VCU) instead of a conventional screen film system. PATIENTS AND METHODS: 53 patients with a suspected vesicouretral reflux were examined with a VCU in analogous and digital technique. The X-rays were taken in a sitting position while simultaneously measuring the bladder pressure. An intraindividual comparison was omitted for X-ray saving reasons. In the follow-up 3 patients were examined with the other system. Two radiologists and two urologists compared 60 VCU of 53 patients--30 VCU in conventional screen film and 30 in DLR technique presented in standard and edge-enhanced images--with regard to image quality according to 3-step score (A--good image quality, B--sufficient image quality, C--insufficient image quality). RESULTS: The 59 conventional films were scored 72 times with an A, 76 times with a B, and 72 times with a C, whereas the DLR films were scored 116 times with an A, 72 times with a B, and only 8 times with a C. Hereby the edge-enhanced images were the most useful for distinguishing the bladder shadow from the soft tissue of the thigh and for detecting reflux. Furthermore, the exposure dose when applying DLR could be decreased to 75% in grown-ups and to 57% in children without any significant loss of information. CONCLUSION: The DLR is highly superior to the conventional film screen system because of its relatively high tolerance towards wrong exposures, especially with respect of the sitting position during MCU. With the DLR we obtained 96% and with the conventional system only 63% films usable for diagnosis.     

Risk of recurrent biliary tract disease after cholecystectomy in patients with duodenal diverticula

OBJECTIVE: To determine if the presence of duodenal diverticula predisposes to the development of common bile duct stones. DESIGN: Cohort study; median follow-up, 10.0 years (25th and 75th percentiles, 5.2 and 16.1 years, respectively). SETTING: Tertiary care center. PATIENTS: One hundred fifty-seven patients with radiologically diagnosed duodenal diverticula who had undergone cholecystectomy from 1950 through 1987 and were asymptomatic at the initiation of follow-up. MAIN OUTCOME MEASURES: All patients were followed up for evidence of recurrent biliary tract disease to the following end points: (1) evidence of choledocholithiasis demonstrated by radiologic surgical, or biochemical means and (2) clinical or biochemical evidence of biliary pancreatitis. RESULTS: Of the 157 patients in the study cohort, 13 patients were categorized as having had recurrent biliary tract disease. Using the Kaplan-Meier survivorship method, the cumulative probabilities of recurrent biliary tract disease in patients with radiologically diagnosed duodenal diverticula were 3.6% at 5 years (95% confidence interval, 0.5-6.9), 5.5% at 10 years (95% confidence interval, 1.5-9.4), and 10.2% at 15 years (95% confidence interval, 3.8-16.7). Age, common bile duct exploration and choledochotomy, and the presence of common bile duct dilatation were not found to be significantly associated with recurrence based on a univariate analysis of risk factors by means of the log-rank statistic. CONCLUSIONS: For patients with radiologically diagnosed, second-portion duodenal diverticula, the risk of developing recurrent bile duct stones after cholecystectomy is lower than has been suggested in previous studies. In the absence of concurrent choledocholithiasis, sphincterotomy or biliary bypass at the time of cholecystectomy seems unwarranted.     

Patr-A and B, the orthologues of HLA-A and B, present hepatitis C virus epitopes to CD8+ cytotoxic T cells from two chronically infected chimpanzees

Common chimpanzees (Pan troglodytes) infected with hepatitis C virus (HCV) show a disease progression similar to that observed for human patients. Although most infected animals develop a chronic hepatitis, virus persistence is associated with an ongoing immune response, for which the beneficial or detrimental effects are uncertain. Lines of virus-specific cytotoxic CD8+ T lymphocytes (CTL) have been previously established from liver biopsies of two common chimpanzees chronically infected with HCV-1. The viral epitopes recognized by six lines of CTL have been defined using synthetic peptides and shown to consist of 8 to 9-residue peptides derived from various viral proteins. Five of the epitopes derive from sequences that vary among strains of HCV. The majority of the corresponding variant epitopes from different HCV strains were either recognized less efficiently or not at all by the CTL, suggesting their response may have limited potential for controlling replication of HCV variants. Complementary DNAs encoding class I alleles of the two common chimpanzees, Patr-A, -B, and -C were cloned, sequenced, and transfected individually into a class I-deficient human cell line. Analysis of peptide presentation by the class I transfectants to CTL identified the Patr class I allotypes that present the six epitopes defined here and an additional epitope defined previously. The assignment of epitopes to class I allotypes based upon analysis of the transfected cells correlates precisely with the segregation of antigen-presenting function within a panel of common chimpanzee cell lines and the expression of class I heavy chains as defined by isoelectric focusing. Five of the HCV-1 epitopes are presented by Patr-B allotypes, two epitopes are presented by a Patr-A allotype, and none is presented by Patr-C allotypes.     

Immunochemical particularities of anaphylactic reactions to compounds used in anesthesia

Three adult mini-pigs were employed to assess the effects of a twice daily dosage (40 mg kg-1) of oxytetracycline hydrochloride (OTC) and a combination of OTC with (0.5 mg kg-1) bromhexine hydrochloride (BHC) on the rheological properties and wet weight of secreted tracheal mucus. Mucus was collected daily from open-ended tracheal pouches established surgically in the mini-pigs. After a five day control period, either OTC or OTC plus BHC was administered twice daily with the normal diet. Each study period was followed by a five day washout period when mucus was collected but no drug given. The viscoelastic properties of each mucus sample were determined using creep compliance analysis. OTC was shown to increase the residual shear viscosity IP < 0.01) and increase the instantaneous compliance (P < 0.01). An increase in the wet weight of the collected mucus occurred in one pig only (P < 0.01). When BHC was co-administered with OTC, all of these changes were abolished. Evidence was obtained to suggest that BHC increased the concentration of OTC within the secreted mucus. BHC appeared to reverse the mucospissic activity of OTC in-vivo.     

CD4-independent, CCR5-dependent infection of brain capillary endothelial cells by a neurovirulent simian immunodeficiency virus strain

Brain capillary endothelial cells (BCECs) are targets of CD4-independent infection by HIV-1 and simian immunodeficiency virus (SIV) strains in vitro and in vivo. Infection of BCECs may provide a portal of entry for the virus into the central nervous system and could disrupt blood-brain barrier function, contributing to the development of AIDS dementia. We found that rhesus macaque BCECs express chemokine receptors involved in HIV and SIV entry including CCR5, CCR3, CXCR4, and STRL33, but not CCR2b, GPR1, or GPR15. Infection of BCECs by the neurovirulent strain SIV/17E-Fr was completely inhibited by aminooxypentane regulation upon activation, normal T cell expression and secretion in the presence or absence of ligands, but not by eotaxin or antibodies to CD4. We found that the envelope (env) proteins from SIV/17E-Fr and several additional SIV strains mediated cell-cell fusion and virus infection with CD4-negative, CCR5-positive cells. In contrast, fusion with cells expressing the coreceptors STRL33, GPR1, and GPR15 was CD4-dependent. These results show that CCR5 can serve as a primary receptor for SIV in BCECs and suggest a possible CD4-independent mechanism for blood-brain barrier disruption and viral entry into the central nervous system.     

Low lipid concentrations in critical illness: implications for preventing and treating endotoxemia

OBJECTIVES: To determine the prevalence and clinical significance of hypolipidemia found in critically ill patients, and whether the addition of a reconstituted lipoprotein preparation could inhibit the generation of tumor necrosis factor-alpha (TNF-alpha) in acute-phase blood taken from these patients. SETTING: Surgical intensive care unit (ICU) of a large urban university hospital. DESIGN: Prospective case series. PATIENTS: A total of 32 patients with a variety of critical illnesses had lipid and lipoprotein concentrations determined. Six patients and six age- and gender-matched control subjects had whole blood in vitro studies of the effect of lipoprotein on lipopolysaccharide mediated TNF-alpha production. INTERVENTIONS: Blood samples were drawn on admission to the ICU and over a subsequent 8-day period. MEASUREMENTS AND MAIN RESULTS: Mean serum lipid and lipoprotein values obtained from patients within 24 hrs of transfer to the surgical ICU were extremely low: mean total cholesterol was 117 mg/dL (3.03 mmol/L), low-density lipoprotein cholesterol 71 mg/dL (1.84 mmol/L), and high-density lipoprotein cholesterol 25 mg/dL (0.65 mmol/L). Only the mean triglyceride concentration of 105 mg/dL (1.19 mmol/L), and the mean lipoprotein(a) concentration of 25 mg/dL (0.25 g/L) were within the normal range. During the first 8 days following surgical ICU admission, there were trends toward increasing lipid and lipoprotein concentrations that were significant for triglycerides and apolipoprotein B. Survival did not correlate with the lipid or lipoprotein concentrations, but patients with infections had significantly lower (p = .008) high-density lipoprotein cholesterol concentrations compared with noninfected patients. Lipopolysaccharide-stimulated production of TNF-alpha in patient and control blood samples was completely suppressed by the addition of 2 mg/mL of a reconstituted high-density lipoprotein preparation. CONCLUSIONS: Patients who are critically ill from a variety of causes have extremely low cholesterol and lipoprotein concentrations. Correction of the hypolipidemia by a reconstituted high-density lipoprotein preparation offers a new strategy for the prevention and treatment of endotoxemia.