脉冲电流对胰岛素经皮渗透的促进作用

实验结果表明,脉冲电流能有效地提高胰岛素的透皮扩散速率,并随着释放池中胰岛素浓度的递增,透皮扩散速率呈线性增加。同时,胰岛素在pH值偏离等电点的酸性溶液(pH3.6)中透皮速率最高,为324.2±33.4μU/(cm²·h),而在pH值高于等电点的溶液(pH7.4)中其透皮速率降至143.7±27.3μU/(cm²·h),在pH值接近等电点(pH5.3)时,胰岛素的透皮速率最低,为78.4±21.9μU/(cm²·h)。     

Real-Time Hypoglycemia Prediction Suite Using Continuous Glucose Monitoring: A safety net for the artificial pancreas

OBJECTIVE

The purpose of this study was to develop an advanced algorithm that detects pending hypoglycemia and then suspends basal insulin delivery. This approach can provide a solution to the problem of nocturnal hypoglycemia, a major concern of patients with diabetes.

RESEARCH DESIGN AND METHODS

This real-time hypoglycemia prediction algorithm (HPA) combines five individual algorithms, all based on continuous glucose monitoring 1-min data. A predictive alarm is issued by a voting algorithm when a hypoglycemic event is predicted to occur in the next 35 min. The HPA system was developed using data derived from 21 Navigator studies that assessed Navigator function over 24 h in children with type 1 diabetes. We confirmed the function of the HPA using a separate dataset from 22 admissions of type 1 diabetic subjects. During these admissions, hypoglycemia was induced by gradual increases in the basal insulin infusion rate up to 180% from the subject''s own baseline infusion rate.

RESULTS

Using a prediction horizon of 35 min, a glucose threshold of 80 mg/dl, and a voting threshold of three of five algorithms to predict hypoglycemia (defined as a FreeStyle plasma glucose readings <60 mg/dl), the HPA predicted 91% of the hypoglycemic events. When four of five algorithms were required to be positive, then 82% of the events were predicted.

CONCLUSIONS

The HPA will enable automated insulin-pump suspension in response to a pending event that has been detected prior to severe immediate complications.The Diabetes Control and Complications Trial (DCCT) proved that glucose control in the closer-to-normal range (tight glycemic control) reduced the likelihood of eye, kidney, nerve, and cardiovascular complications of diabetes (1,2). Unfortunately, the DCCT also showed that the incidence of severe hypoglycemia was three times higher in the intensively treated group compared with the standard treatment group (1). In the DCCT, 55% of the severe lows occurred during sleep hours (1). Further, in the adolescent portion of the DCCT, the risk for severe hypoglycemia was even greater, with one episode every 1.17 years (85.7 per 100 patient-years) (2). One report in children found 75% of severe lows to occur during the nighttime hours (3). The high frequency and duration of nocturnal hypoglycemia has been confirmed in clinical research center (CRC) studies, in which frequent laboratory reference glucose values were obtained. For example, in a DirecNet study of exercise-induced nocturnal hypoglycemia, children who did not exercise had a 28% incidence of nocturnal hypoglycemia (glucose <60 mg/dl), and those who exercised had a 48% incidence of nocturnal hypoglycemia (4). In a recent study (5) of bedtime snacks and nocturnal hypoglycemia, on nights when adult subjects did not have a snack, 57% became hypoglycemic (<70 mg/dl), with an average duration of hypoglycemia of over 2.5 h. In this study, the duration of hypoglycemia was as long as 8.75 h.Real-time continuous glucose monitoring (CGM) is becoming available with the Food and Drug Administration (FDA) approval of the MiniMed Guardian, the DexCom STS, and the Abbott Navigator. One of the major perceived benefits of real-time glucose monitoring is the ability of these devices to have alarms for hypoglycemia. For a real-time alarm to be effective, it must awaken a sleeping subject. The first FDA-approved real-time glucose monitor was the GlucoWatch^TM. To determine whether the alarm function on the GlucoWatch was effective in awakening children while they were sleeping, an infrared camera was used to videotape them throughout the night in the CRCs. During this admission, reference glucose values were obtained every half hour to document hypoglycemia. In this study, 71% of youths wearing the watch did not respond to nighttime alarms (6), placing these patients at a risk for nocturnal hypoglycemia despite wearing a real-time continuous glucose sensor. One possible correction of this problem would be to have the sensor send a signal to the pump so that it will stop infusing insulin when pending or real hypoglycemia has been reached and the patient has not responded to alarms. This is the primary focus of the hypoglycemia prediction algorithm.Previous studies (7–9) have shown that when insulin infusion is stopped for 2 h or when an infusion set is disconnected for up to 30 min (7), there is essentially no risk of the patient developing significant ketones or acidosis. Three previous studies (8–10) have demonstrated that turning off an insulin pump for 2 h did not result in diabetic ketoacidosis (DKA). In all three studies, blood β-hydroxybutyrate concentrations were determined using both a meter (Precision Xtra^TM) and the hospital laboratory. In two of the studies (9,10), the continuous subcutaneous insulin infusion pumps were purposely turned off for periods of 4 and 5 h, with a gradual increase in β-hydroxybutyratek concentrations after 2 h to the upper normal range. No cases of DKA occurred in these studies.     

球体培养人、猪肝细胞：一种理想的体外生物人工肝模式

体外培养的肝细胞有多种临床用途〔１〕。其中将肝细胞置入特殊的生物反应器,构建生物人工肝（ｂｉｏａｒｔｉｆｉｃｉａｌｌｉｖｅｒ,ＢＡＬ）支持系统有重要的临床价值。有研究报道,细胞聚集成多细胞的球体（ｓｐｈｅｒｉｏｄ）更类似于体内条件;并且可在有限的容积内高密度地培养肝细胞〔２〕。因此,我们实验构建人、猪肝细胞球体,并比较肝细胞普通培养与球体培养蛋白分泌功能的变化。１．材料和方法：试剂：Ｄｕｂｅｃｃｏ′ｓ磷酸盐缓冲液;Ｈａｎｋ′ｓ平衡盐;ＩＴＳ（胰岛素,运铁蛋白和硒,ｉｎｓｕｌｉｎ,ｔｒａｎｓｆｅｒ…     

Rotator cuff sonography: a reassessment

This study is both a retrospective and prospective evaluation of the clinical usefulness of shoulder sonography. Ninety-eight patients suspected of having rotator cuff tears underwent sonography of both shoulders. Sixty-two patients underwent double-contrast arthrography performed on the same day as sonography, and 38 patients underwent surgery after sonography. A comparison of the results from ultrasound and arthrography, using published diagnostic criteria, demonstrated a sensitivity of 75% and a specificity of 43% for detection of a rotator cuff tear. In this study, use of more restricted criteria, a subset of the published criteria, yielded a sensitivity of 68% and a specificity of 90%. A comparison of sonography with surgery, using this study's criteria, demonstrated a sensitivity of 57% and a specificity of 76%. This report shows that shoulder sonography is less reliable than previously reported and appears to have a very limited role in the evaluation of rotator cuff injuries.     

加钖果宁的镇痛作用及其作用机制

野花椒系芸香科植物(Zanthoxylum simulans Hance),其根皮有止痛及局麻作用。其水溶性生物碱有肌松作用,曾用于外科手术作为中麻辅助用药。常志青从中分离到加钖果宁[(—)edulinine,简称加钖碱,下同],并发现有镇痛及中枢抑制作用。本文进一步证明其镇痛作用及其作用机制与阿片受体有关。     

Equivocal mammographic findings: evaluation with spot compression

Seventy-five spot compression views of equivocally suspicious lesions detected at routine mammographic examination of 72 women were reviewed in this retrospective study. Sixty-five of the 75 lesions appeared less suspicious on spot compression views, two did not change, and eight appeared more suspicious. Biopsy findings confirmed that the eight more suspicious lesions were cancer. The adjunctive use of spot compression helped characterize equivocal findings seen on routine mammographic views and improved the accuracy of mammographic interpretation.     

Breast calcifications: analysis of imaging properties

The imaging characteristics of microcalcifications in both benign and malignant breast conditions were analyzed in 48 digitized film mammograms. Each case included in this analysis had findings considered suggestive of malignancy by the radiologist, with the underlying histologic structure determined by excisional biopsy. Imaging properties of each microcalcification--such as pixel intensity, relative location, distribution, size, and local neighborhood intensities--were recorded. This information was statistically analyzed at the population level according to such selection criteria as histologic type, size of calcification, and cluster size. Distribution ranges were determined for these criteria. Statistical differences between data from benign and malignant cases show the average distance between calcifications in malignant conditions was greater than in benign conditions, and tissue region averages surrounding calcifications associated with malignant conditions were consistently higher than those for benign conditions.     

Paranasal sinuses: CT imaging requirements for endoscopic surgery

Recent advances in the understanding of mucociliary activity and the pathophysiology of the nasal cavity and paranasal sinuses have revolutionized the surgical management of chronic and/or recurrent sinusitis. Meticulous radiographic delineation of the small structures in this region, coupled with endoscopic evaluation, provides detailed preoperative information regarding morphology and pathology. This information has led to more focused endoscopic surgical procedures, which have dramatically reduced patient morbidity. As a consequence, there is now worldwide interest among otolaryngologists in the radiologic definition of paranasal regional anatomy. For effective interactions between radiologist and otolaryngologist, the former must be prepared to render interpretations that address these "microanatomic" locales. This communication is directed at familiarizing the radiologist with these observations and concepts, considering both normal and disturbed anatomy with their attendant pathophysiologic and therapeutic implications.