Urine-compatible polymer for long-term ureteral stenting

Internal double-J ureteral stents were designed from a urine-compatible polymer (C-Flex), and 35 stents were placed in patients. The overall patency rate for the stents was 80%, with most stent failures occurring before 2 months; the follow-up period ranged from 2 to 16 months, with a mean follow-up for all stents of 5.0 months. Stents were considered patent at last follow-up only if they had been in place for at least 2 months. No migration or fracture of the stents occurred. Physical properties of urine-exposed stents were compared with those of virgin tubing and tubing exposed for 1 year to shelf conditions. Stent patency was optimized by increasing urine flow by increasing the patient's voluntary oral intake, administering prophylactic oral antibiotics, and avoiding placement of stents into grossly bloody or infected collecting systems.     

Enhancement of chemotactic factor-stimulated neutrophil oxidative metabolism by leukotriene B4

Leukotriene B4 (LTB4) is a potent primary stimulator of neutrophil chemotaxis, aggregation, and degranulation and induces superoxide production at higher concentrations. In order to determine whether LTB4 modulates neutrophil responses to oxidative stimuli, human neutrophils (PMNs) were incubated with LTB4 prior to stimulation with f-Met-Leu-Phe (fMLP, 10(-7) mol/L), opsonized zymosan (OZ, 250 micrograms/mL), or phorbol myristate acetate (PMA, 32 nmol/L). Superoxide (O2-) production by stimulated PMNs was assessed by the superoxide dismutase-inhibitable reduction of cytochrome c. LTB4 alone did not stimulate O2- production in concentrations below 10(-7) mol/L and had no effect on the O2- assay. In the concentration range of 10(-12) to 10(-8) mol/L, LTB4 did not alter O2- release induced by OZ or PMA. In contrast, LTB4-treated cells demonstrated enhanced O2- production following exposure to fMLP, and in the presence of 10 nmol/LLTB4, generated 180% +/- 41% of O-2 quantities produced by control cells (n = 23). Enhancement was LTB4 dose-dependent, was maximal in the range of 1 to 10 nmol/L LTB4, was not reversed by removal of the lipid from the medium prior to fMLP stimulation, and was not dependent on the presence of Ca++ or Mg++ in the suspending medium. Chemiluminescence of fMLP-stimulated neutrophils was increased to 323% of controls in neutrophils preincubated with 10 nmol/L LTB4. Unlike augmentation of oxidative responses to fMLP seen with other degranulating stimuli, enhancement by LTB4 was not correlated with an increase in 3H-fMLP receptor binding. These results indicate that, in addition to its primary effects on neutrophil function, LTB4 modulates PMN oxidative responses to the chemotactic peptide and, thus, may amplify the release of oxygen metabolites at inflammatory foci.     

Chronic hemolytic anemia due to a monoclonal IgG cold agglutinin with anti-Pr specificity

Immunologic studies performed in a case of autoimmune chronic hemolytic anemia with low titer cold agglutinins (1/16) demonstrated that the cold agglutinins corresponded to monoclonal IgG with anti-Pr specificity. This antibody had a large thermal amplitude, being active at 37 degrees C. These unusual characteristics may define a distinct subset of chronic cold agglutinin disease.     

The Coraliance study: non-compliant behavior. Results after a 6-month follow-up of patients on oral contraceptives

Objectives This follow-up study was planned to establish the frequency with which women miss their contraceptive pill, and to observe their behavior when they forget it. In those women who changed from a continuous cycle to an interrupted type of cycle, or vice versa, the study also aimed to evaluate the impact of this change on the pattern of omission of pills. Methods The longitudinal, prospective cohort study included healthy women of child-bearing age for whom a change of pill was being prescribed by their gynecologist. Data were recorded during the 6 months preceding inclusion in the study, and for the 6 months of follow-up; the women were asked to complete a diary in which they recorded the number and exact times of pill omission, and their behavior at each omission. Results A total of 617 gynecologists included 3316 women into the study; of these, a group of 2418 (73%) revisited the same gynecologist at follow-up. The groups who either visited the same or a different gynecologist were similar with respect to age, oral contraception type, omission type and frequency. A large non-compliance rate and women's difficulties in maintaining safe contraception after missing a pill were observed in the group with follow-up. Women were never risk-free when they missed a pill; they turned to numerous sources for discordant or conflicting information; 15% of 'not-forgetting' women at the pre-inclusion cycle recorded at least one omission at the last cycle of the 6-month follow-up period. Omission fluctuations during the observational period make it difficult to designate 'forgetful' or 'non-forgetful' classes of women. Administration of the pill in a continuous cycle, and probably 'study' and 'auto-questionnaire' effects, contributed to an improvement in compliance. In the group taking the continuous cycle pill, the omission number slightly decreased, particularly on the first day and week of the cycle, irrespective of the initial cycle type. Conclusions The importance of the phenomenon of non-compliance rate is confirmed as well as women's difficulties in knowing how to maintain contraceptive safety. The continuous cycle regimen is likely to improve women's compliance during the critical period of the cycle.     

T2 values in the human brain: comparison with quantitative assays of iron and ferritin

Magnetic resonance (MR) imaging with a whole-body imager was performed in 10 fresh, unfixed whole human brains selected randomly from cadavers. All subjects were neurologically intact before death. T2 time constants were measured within the caudate nucleus, putamen, globus pallidus, cortical gray matter, subcortical white matter, and optic radiation. These regions were then excised, and T2 values were measured again with a 1.5-T MR spectrometer. Quantitative assays of iron, ferritin, and protein from these areas were then performed. Iron concentration varied significantly among brain regions, whereas ferritin and protein concentrations were constant among brain regions and among individuals. Neither iron nor ferritin concentration showed any consistent correlation with T2 values. Histologic examination of brain micro-sections with iron- and ferritin-specific stains of demonstrated poor correlation with biochemical assays of ferritin and iron concentrations. Results indicate that T2 values correlate poorly with iron and ferritin concentrations found in neurologically intact brains.     

假肿瘤性胰腺炎的CT表现

目的 提高对慢性假肿瘤性胰腺炎的影像学特征的认识,材料与方法 回顾性分析１２例经临床、病理诊断的假肿瘤性胰腺炎的特点,结果 １２例均见胰产质肿块形成,大多为类圆形,直径为２．５～４ｃｍ,边缘规则,肿块较均质,如肿块较大,则密度不均,中心坏死,边缘不规则,８例肿块内有钙化,ＣＴ增强扫描肿块大多呈明显强化,１１例位于胰头部,１例位于胰体部,７例Ｂ超呈低回声,５例为不均匀回声,结论 假肿瘤性胰腺炎与胰腺     

Abnormal renal vasodilation to an amino acid infusion in congestive heart failure: normalization by enalapril

In congestive heart failure (CHF), the neurohormonal mechanisms that cause renal vasoconstriction, particularly those depending on the renin-angiotensin system, could interfere with renal vasodilating mechanisms. To elucidate this issue, we studied the kidney response to an amino acid infusion (known to cause renal vasodilation in healthy individuals) in eight patients with CHF. We found that the amino acid infusion (0.7 mL/kg/h of a 10% solution) elicited no renal hemodynamic response, in marked contrast to healthy subjects. We next hypothesized that the renin-angiotensin system (known to be activated in heart failure) has a role in the lack of response to the amino acid infusion. To test this hypothesis, we repeated the study after two 5-mg doses of enalapril, an inhibitor of the angiotensin-converting enzyme, administered 12 hours apart. After enalapril treatment, the amino acid infusion caused a 45% increase in mean renal blood flow (RBF) from 383 +/- 55 to 557 +/- 51 mL/min at the fifth hour (P < 0.05). This normalization of the renal response to the amino acid infusion occurred without changes in cardiac output or in systemic vascular resistance. Hence, the renal fraction of the cardiac output increased during the amino acid infusion. The recovery of the renal vascular response was not accompanied by an increase in glomerular filtration rate (GFR; filtration fraction decreased), suggesting a predominant efferent arteriole dilatation. Our study shows that, in heart failure, the kidney loses its ability to increase RBF in response to an amino acid load. This lack of renal vascular response can be restored by inhibiting the renin-angiotensin system and is unrelated to changes in systemic hemodynamics.