叶绿素衍生物在犬膀胱粘膜内代谢的研究

目的：为了了解叶绿素衍生物（ＣＰＤ４）口服后在膀胱粘膜内含量变化的状况，以便为临床应用提供实验依据。方法：１３条实验犬分为３个不同剂量组，应用荧光检测法作服药后不同时段膀胱粘膜ＣＰＤ４含量的测定。结果：ＣＰＤ４用于实验犬的合适剂量是１００ｍｇ／ｋｇ，明显低于此值将显著影响组织的吸收，从而降低光动力作用。在禁食组中，组织内吸收的最高峰值出现在服药后２ｈ，而进食组却推迟出现在服药后６￣１２ｈ。结论：为     

脑内GABA能神经元对红藻氨酸中枢性心血管效应的影响

采用侧脑室微最注射法证明,谷氯酸受体哑型激动剂红藻氨酸(KA)可依剂量性地升高大鼠血压和加快心率。预先给予GABA合成抑制剂氮基脲140 mg/kg ip或GABA拮抗剂印防己毒1 mg/kg iv均可明显增强KA的作用;而GABA转氨酶抑制剂氨氧乙酸25μg/rat icv明显减弱KA的作用。结果表明,脑内GABA能神经元功能受抑,KA的中枢性心血管效应增强。从而推测,脑内GABA能神经元与谷氯酸能神经元之间相互制约,共同参与中枢性调节心血管的活动。     

The relationship between hospital volume and outcome in bariatric surgery at academic medical centers

OBJECTIVE: To examine the effect of hospital volume of bariatric surgery on morbidity, mortality, and costs at academic centers. SUMMARY BACKGROUND DATA: The American Society for Bariatric Surgery recently proposed categorization of certain bariatric surgery centers as "Centers of Excellence." Some of the proposed inclusion criteria were hospital volume and operative outcomes. The volume-outcome relationship has been well established in several complex abdominal operations; however, few studies have examined this relationship in patients undergoing bariatric surgery. METHODS: Using the International Classification of Diseases, 9th edition, diagnosis and procedure codes, we obtained data from the University HealthSystem Consortium Clinical Data Base for all patients who underwent Roux-en-Y gastric bypass for the treatment of morbid obesity between 1999 and 2002 (n = 24,166). Outcomes of bariatric surgery, including length of hospital stay, 30-day readmission, morbidity, observed and expected (risk-adjusted) mortality, and costs were compared between high-volume (>100 cases/year), medium-volume (50-100 cases/year), and low-volume hospitals (<50 cases/year). RESULTS: There were 22 high-volume (n = 13,810), 27 medium-volume (n = 7634), and 44 low-volume (n = 2722) hospitals included in our study. Compared with low-volume hospitals, patients who underwent gastric bypass at high-volume hospitals had a shorter length of hospital stay (3.8 versus 5.1 days, P < 0.01), lower overall complications (10.2% versus 14.5%, P < 0.01), lower complications of medical care (7.8% versus 10.8%, P < 0.01), and lower costs ($10,292 versus $13,908, P < 0.01). The expected mortality rate was similar between high- and low-volume hospitals (0.6% versus 0.6%), demonstrating similarities in characteristics and severity of illness between groups. The observed mortality, however, was significantly lower at high-volume hospitals (0.3% versus 1.2%, P < 0.01). In a subset of patients older than 55 years, the observed mortality was 0.9% at high-volume centers compared with 3.1% at low-volume centers (P < 0.01). CONCLUSIONS: Bariatric surgery performed at hospitals with more than 100 cases annually is associated with a shorter length of stay, lower morbidity and mortality, and decreased costs. This volume-outcome relationship is even more pronounced for a subset of patients older than 55 years, for whom in-hospital mortality was 3-fold higher at low-volume compared with high-volume hospitals. High-volume hospitals also have a lower rate of overall postoperative and medical care complications, which may be related in part to formalization of the structures and processes of care.     

Human red blood cell Wright antigens: a genetic and evolutionary perspective on glycophorin A-band 3 interaction

The Wright (Wra/Wrb) blood group polymorphism is defined by an allelic change (Lys658Glu) in the band 3 protein; nevertheless, the Wrb antigen apparently requires glycophorin A (GPA) for surface presentation. To gain insight into the structural basis for this protein-protein interaction and delineate its relationship with Wrb antigen expression, we investigated GPA and band 3 sequence polymorphisms occurring in rare humans and nonhuman primates. The lack of GPA or amino acid residues 59 through 71 of GPA results in the absence of Wrb from human red blood cells (RBCs) exhibiting the MkMk, En(a-), or MiV phenotype. However, the SAT homozygous cells carried a Glu658 form of band 3 and a hybrid glycophorin with the entire GPA extramembrane domain from residues 1 through 71, yet expressed no Wrb antigen. This finding suggests that formation of the Wrb antigenic structure is dependent on protein folding and that the transmembrane junction of GPA is important in maintaining the required conformation. Comparative analyses of GPA and band 3 homologues led to the identification in the interacting regions of conserved and dispensable amino acid residues that correlated with the Wrb positive or negative status on nonhuman primates. In particular, the chimpanzee RBCs cells expressed Wrb and the Glu658 form of band 3, which is identical to humans, but their GPA contained the Gly rather than Arg residue at position 61. Taken together, the results suggest that (1) Arg61 of GPA and the proposed Arg61-Glu658 charge pair are not crucial for Wrb antigen exhibition and (2) the role of GPA for interaction with band 3, including Glu658, probably involves a number of amino acid residues located in the alpha-helical region and transmembrane junction.     

Neck neoplasms: MR imaging. Part I. Initial evaluation

Untreated neoplasms of the neck (tumors of the oropharynx, supraglottic area, carotid body, and thyroid, in addition to malignant lymphadenopathy) were evaluated in 23 patients with magnetic resonance (MR) imaging. The results were compared with computed tomographic (CT) scans in 20 patients. Contrast between tumor and fat was best on relatively T1-weighted images (500/30-35 [TR msec/TE msec]), whereas separation of tumor and muscle was best with relatively T2-weighted pulse sequences (1,500/90). Balanced images (1,500/30-35) provided best overall image quality and best demonstrated vascular anatomy. MR imaging was usually superior to CT in showing the relationship of tumor mass to muscle. MR imaging and contrast material-enhanced CT were equivalent in most patients in defining vascular anatomy, but MR imaging was superior when intravenous contrast material was not administered. However, CT was more helpful in showing bone and cartilage anatomy, and in some patients CT also was better in showing airway abnormalities. Despite these limitations, MR imaging is a promising imaging technique for studying neoplasms of the neck.     

Fatigue in chronic peritoneal dialysis patients

Fatigue is a common complaint in long termdialysis patients that may influence theirquality of life. The present study was carriedout in order to evaluate the prevalence andcourse of fatigue in a group of chronic PDpatients and to find the possible factor(s)related to its development. We retrospectivelyreviewed 100 charts of the patients previouslyon PD. The presence or absence of fatigue inthe 1st and last clinic visits and the 1st and2nd changes in fatigue state were studiedaccording to the monthly clinical records ofthe primary nurses. Data regarding dialysatevolume, urine volume, weekly erythropoietin(EPO) dose, hemoglobin, hematocrit, blood urea,serum creatinine, residual renal creatinine andurea clearances, dialysate to peritonealcreatinine ratio (D/P Cr), total weekly Kt/Vand total creatinine clearance/l.73 m² bodysurface area (TCrCl) were collected. Fifty-fivepatients were male and 45 female. The mean ageat the 1st clinic visit was 61.3 ± 16 years.At the 1st visit 55 patients had fatigue and 45did not. In 32 of the 55 patients fatiguedisappeared after a mean duration of 7.9 ± 8.4months and in 31 of the 45 patients fatigueappeared after a mean duration of 8 ± 6.8months. So at the last visit the frequency offatigue increased significantly from 55% to67% (p < 0.001). In patients with fatigue themean age and female percentage were higher(64.2 ± 14.1 vs 57.8 ± 17.6, p = 0.05 and 1.2vs 0.5, p < 0.05 respectively), mean hemoglobinconcentration was lower (104.4 ± 14.7 vs110.6 ± 14.2 g/L, p < 0.04) and mean EPO dosewas higher (6379.6 ± 7142 vs 3395.4 ± 4337.8units/week, p < 0.02) at the 1st clinic visit.EPO dose was also higher in patients withfatigue at the last visit (8253.7 ± 10317.3units/wk vs 4736.4 ± 5432.5, p < 0.03). Nocorrelation was found between dialysis adequacyaccording to either weekly Kt/V or TCrCl andnutritional state according to nPCR andfrequency of fatigue. We conclude that fatigueis a common symptom in PD patients and it'sprevalence increases over time. Anemia seemsto be the most important factor associated withfatigue. Dialysis adequacy and nutritionalstate did not show any correlation with thefrequency of fatigue in our study.