Design and preliminary evaluation of an expert system for platelet request evaluation

In spite of growing awareness of the potential risks associated with transfusion, the number of platelet units transfused in the United States continues to increase each year. There is a growing interest in ensuring that all transfusions are administered for appropriate reasons. Prospective review of requests for transfusions has been used to accomplish this goal. Although successful in reducing the number of inappropriate transfusions, this review method requires great time commitments by blood bank personnel and physicians. A knowledge-based system (ESPRE) that aids hospital blood bank personnel in the review of requests for platelet transfusions has been developed. The system automatically obtains most of the required patient data via a direct link to the hospital's main laboratory computers. The system generates a printed report that includes a list of patient-specific data, a list of the conditions for which a transfusion would be appropriate for the particular patient (given the clinical condition), and the conclusions drawn by the system. During a preliminary clinical evaluation of ESPRE, 73 randomly selected platelet transfusion requests were evaluated for approval by laboratory personnel and ESPRE. Overall, ESPRE would have approved 71 of the requests and laboratory staff would have approved 72. Forty-four percent of the requests would have been approved for the same reasons given by the staff. There were only three disagreements on final approval between ESPRE and blood bank personnel. This computerized expert system is a promising approach to the prospective review of all platelet transfusions.     

Computer-aided infrared analysis of urinary calculi

We have created a library of 497 digitized infrared spectra of 58 components of urinary calculi and of their usual binary and ternary mixtures. We tested the operation of the "Birsy" search program (Bruker Analytische Messtechnik) with this library for the interpretation of infrared spectra of 50 urinary calculi, selected from both classical and difficult cases. This program correctly identifies the two first components 98% of the time and the third (minor) component 70% of the time. Using this program, those without training or experience in infrared analysis can routinely use the infrared method of analysis of urinary calculi.     

Same patient, new stone composition: amprenavir urinary stone

We report here the first case to add amprenavir to the growing list of antiretroviral drugs associated with urinary stones. The first reported case of a nelfinavir urinary stone was reported in 2002 in a 37-year-old HIV-infected woman. In September 2007, the same female patient was referred to our department with recent onset of right flank pain and recurrent urinary tract infections. Abdominal computed tomography revealed three obstructing stones in the distal right ureter, another stone in the right renal pelvis with hydronephrosis and a stone in the left kidney. After stone retrieval, analysis of the stone by liquid chromatography with mass spectrometry revealed a stone composition of 95% unmodified amprenavir and 5% ritonavir.     

Diffuse reflectance technique for infrared analysis of urinary calculi

We investigated the application of diffuse reflectance infrared Fourier transform spectroscopy to analysis of urinary calculi and compared its operation with that of older sampling techniques (pellet, mull, and attenuated total reflectance). The new method requires shorter sample preparation time and less sample (30 micrograms). Quantitative measurements are easier. Because of the additivity of the Kubelka-Munk functions, a quasi-exhaustive collection of infrared spectra of mixtures of possible components of stones can be compiled, facilitating a computerized intrepretation of infrared spectra of urinary calculi.     

微创经皮肾镜取石术治疗上尿路结石80例临床观察

目的 观察微创经皮肾取石术治疗上尿路结石的临床效果.方法 对我院80例尿路结石患者采用B超定位引导经皮肾穿刺建立F16通道,使用用德国WOLF8/9.8 F输尿管肾镜结合气压弹道碎石机碎石.结果 80例患者行Ⅰ期穿刺取石69例,行Ⅱ期取石8例,行Ⅲ期取石3例.结石清除率93.75%（75/80）.手术时间0.6～3.6 h,术中无需要输血病例,未见严重并发症.结论 微创经皮肾取石术治疗上尿路结石疗效好、创伤小、结石清除率高、并发症少,对残留结石和复发结石的再次手术治疗有较大优越性,配合体外冲击波碎石可进一步提高肾结石的清除率,有较高的临床应用价值.     

A wet chemistry method for the analysis of urinary calculi

A procedure for the routine investigation of urinary calculi is described. The investigation scheme was based on existing methods in the routine laboratory for calcium(II), magnesium(II), phosphate and urate in serum. The substance content of oxalate was calculated as non-phosphate-bound calcium(II). Furthermore the test for cystine in urine was utilized. Two specially designed tests were used, one for carbonate apatite and one for verification of the presence of oxalate. The scheme was applied to 30 specimens of human origin. The sum of the mass fractions of identified and calculated components in the calculi was found to be 0.88 on the average (s = 0.05). Low values for this sum may serve as an indication of the presence of rare components that are not included in this analytical programme. A few calculi containing rare components required special methods for the investigation and are most conveniently investigated in a specialized laboratory using X-ray diffraction or infra-red spectrometry. In this paper, however, we describe wet chemistry methods, suitable for reliable cystine determinations and for oxalate in calculi containing, for example, brushite, where the calculated oxalate value is uncertain. These methods may be used as an alternative to the physical methods for many of the rare calculi.     

A method for quantitative wet chemical analysis of urinary calculi

We describe a simple method for quantitative chemical analysis of urinary calculi requiring no specialized equipment. Pulverized calculi are dried over silica gel at room temperature and dissolved in nitric acid. which was the only effective agent for complete dissolution. Calcium, magnesium, ammonium, and phosphate are then determined by conventional methods. Oxalate is determined by a method based on the quenching action of oxalate on the fluorescence of a zirconium-flavonol complex. Uric acid, when treated with nitric acid, is stoichiometrically converted to alloxan, which is determined fluorimetrically with 1,2-phenylenediamine. Similarly, cystine is oxidized by nitric acid to sulfate, which is determined turbidimetrically as barium sulfate. Protein is determined spectrophotometrically as xanthoprotein. The total mass recovery of authentic calculi was 92.2 ± 6.7 (SD) per cent. The method permits analysis of calculi as small as 1.0 mg. Internal quality control is performed with specially designed control samples.     

A wet chemistry method for the analysis of urinary calculi

A procedure for the routine investigation of urinary calculi is described. The investigation scheme was based on existing methods in the routine laboratory for calcium(II), magnesium(II), phosphate and urate in serum. The substance content of oxalate was calculated as non-phosphate-bound calcium(II). Furthermore the test for cystine in urine was utilized. Two specially designed tests were used, one for carbonate apatite and one for verification of the presence of oxalate. The scheme was applied to 30 specimens of human origin. The sum of the mass fractions of identified and calculated components in the calculi was found to be 0.88 on the average (s = 0.05). Low values for this sum may serve as an indication of the presence of rare components that are not included in this analytical programme. A few calculi containing rare components required special methods for the investigation and are most conveniently investigated in a specialized laboratory using X-ray diffraction or infra-red spectrometry. In this paper, however, we describe wet chemistry methods, suitable for reliable cystine determinations and for oxalate in calculi containing, for example, brushite, where the calculated oxalate value is uncertain. These methods may be used as an alternative to the physical methods for many of the rare calculi.     

高龄泌尿系统结石患者术后并发症的临床分析

目的分析高龄泌尿系统结石患者术后并发症的情况及处理对策。方法回顾性分析66例经泌尿外科手术的高龄患者临床资料。全部患者中,男40例,女26例。患者平均年龄(72.9±1.3)岁。疾病类型:输尿管结石(35例,53.03%),肾结石(18例,27.27%),输尿管结石合并肾结石(13例,19.7%)。本次手术类型:皮肾镜手术8例(12.12%),输尿管镜或软镜手术58例(87.88%)。分析术后并发症情况,总结临床采取的相应的处理对策以及临床经验。结果 14例发生并发症(21.21%)。其中,尿路感染6例(9.09%),尿路感染伴发热1例(1.52%),切口感染2例(3.03%),输尿管狭窄1例(3.03%),轻度肾周积液1例(1.52%);术后发生结石残留15例(22.73%),再次手术后结石残留3例(4.55%)。术后并发症均经及时抗感染和对症处理,患者康复出院。结论术后发生结石残留和尿路感染等为泌尿外科高龄结石患者术后常见的并发症,临床需积极防控并结合临床实际给予合理的技术处置对策。     

含三聚氰胺奶粉致婴幼儿泌尿系结石的X线表现（附25例分析）

静脉肾盂造影是诊断泌尿系疾病的重要方法之一.采用数字胃肠造影机电视监视下点片观察,并结合图像后处理技术.大大提高了影像诊断质量,患儿常规采用医用非离子型造影剂碘海醇300,大大降低了患儿肾功能损害,准确判断肾盂肾盏积水、结石及肾分泌功能情况,为临床诊断及治疗提供了可靠的依据.     

泌尿系结石的X线平片准确性分析

目的评价X线对泌尿系结石的诊断价值。方法对328例泌尿系结石患者的B超、X线检查结果进行对比分析。结果B超、X线对泌尿系结石均有较高的诊断率,分别为78．7％和89．3％。结论X线诊断泌尿系结石的准确率更高,应为泌尿系结石的诊断的首选方法,同时辅以B超提高准确率。     

Quantitative X-ray diffraction analysis of urinary calculi by use of the internal-standard method and reference intensity ratios

The internal-standard method and the powder diffractometer have been applied here to the quantitative determination of urinary stone constituents by x-ray diffraction (XRD). Reference intensity ratios determined for six stone substances were used in the reduction of intensity data. Constituent concentrations calculated for 21 stones were compared with values obtained from an element-sensitive technique. We conclude that XRD analysis alone cannot be regarded as a routine technique for the quantitative characterization of uroliths, but that semiquantitative XRD analysis supplemented by accurate quantitative elemental data is more suitable for the precise determination of true stone composition.     

The analysis of peculiar urinary (and other) calculi: an endless source of challenge.

The exact composition of calculi is clinically important, but many specimens are not examined, with resultant loss of important information. We describe the incidence and nature of false stones, peculiar calculi and crystals growing on surprising materials. We studied 3100 calculi (97% urinary, 2% digestive and 1% others). Fourier transform infrared spectroscopy was used to identify calculi by detailed comparison with libraries of reference spectra. We also used UV-visible spectroscopy, nuclear magnetic resonance and gas chromatography-mass spectrometry for specific situations. Among 3100 calculi, 154 (5%) had an unusual composition; 101 specimens (3.3%) were false calculi or artifacts, 31 (1%) contained drugs or metabolites and 22 (0.7%) corresponded to crystallizations around other materials. The findings contribute to immediate patient management and to advances in scientific and medical knowledge. We conclude that the analysis of all calculi must be carried out, to determine their composition, and an efficient strategy must be used.     

Knowledge acquisition and evaluation of an expert system for managing disorders of the outer eye

The aim of the current study was to develop and evaluate an expert system for diagnosing outer eye disorders, intended to support family physicians and nurse practitioners in the management of patients with minor eye complaints. The knowledge in the program was gathered from the scientific literature and from 6 experienced ophthalmologists and 6 ophthalmic nurses. Fourteen diagnoses must be considered, and the differential diagnosis is dependent upon 32 signs and symptoms. The program calculates the most likely diagnosis, presents photographs of the typical ocular findings, and provides information regarding management and treatment. The program's output was compared with the diagnosis made by 8 other ophthalmologists at a Swedish university clinic, based on data from 157 patients with disorders of the outer eye, who visited the emergency ward during a one-week period. The concordance between the diagnosis made by the ophthalmologists and the program was 96%. In conclusion, the expert system for disorders of the outer eye provided essentially the same diagnostic information as an examination by an ophthalmologist. Support from the program would make it possible for family physicians and nurse practitioners to manage most of these patients.     

Hematuria as an indicator for the presence or absence of urinary calculi

The purpose of this study was to determine whether the presence of hematuria or its absence can predict the presence or absence of urinary calculi as determined by computed tomography (CT) scan in patients presenting to the ED with acute abdominal colic. We reviewed the urine analysis and CT scans of all patients presenting to the ED over a 12-month period with acute colic and a clinical suspicion of urinary calculi. Urine samples were drawn on arrival in the ED before CT scanning. Two hundred seventy-seven patients were included in the study. The prevalence of urinary stones as detected by CT was 57.4%. The positive predictive value, negative predictive value, and accuracy for hematuria as a marker for stone disease was 60.9%, 72.4%, and 62.1%, respectively. A total of 3.24% of patients had some degree of obstruction, all of whom had hematuria. The absence of hematuria is not a reliable exclusion criterion for urinary calculi. The detection of urinary stones without hematuria does not imply obstruction.