A rapid manual method for routine assay of ascorbic acid in serum and plasma.

A method is described for the assay of ascorbic acid in either serum or heparinized plasma. 1. The assay is based on the reduction of ferric chloride by ascorbic acid with the resulting ferrous ion quantitated by the addition of 2,4,6-tripyridyl-s-triazine to form a purple colour with a maximum absorbance at 595 nm. 2. Uric acid interference has been eliminated by the use of a high molarity acetate buffer and by optimising the amount of TPTZ and ferric chloride used. 3. Protein was found to cause rapid fading of the final colour; it was therefore necessary to remove the protein, by addition of 10% trichloroacetic acid, from the specimen prior to the final assay. This had the added advantage of assisting to stabilize the ascorbic acid prior to final assay. 4. All reagents used are easily obtained and no special equipment is required.     

Comparison of ascorbic acid concentrations in granulocytes and lymphocytes

The author measured the ascorbic acid concentration (microgram/10(8) cells) in leukocytes from fourteen healthy male subjects aged 20 to 28 years. The mean values were 10.9 (range 3.7 to 15.8) in granulocytes and 88.5 (range 35.3 to 122.2) in lymphocytes. These findings suggest that ascorbic acid metabolism in lymphocytes differs from that in granulocytes. In the second experiments the changes in ascorbic acid concentrations were measured in the course of an ascorbic acid loading test to a 33-year-old healthy male volunteer, in which increasing doses (1, 3, 5, 10 g/day X 7 days) were weekly loaded for 4 successive weeks and the ascorbic acid concentrations were examined at the end of each week. As the loading dose increased, ascorbic acid concentration in lymphocytes decreased during the 4 week period while the counterpart value in granulocytes stayed essentially constant. The present findings suggest the differences in ascorbic acid metabolism between granulocytes and lymphocytes.     

Simplified determination of urinary delta-aminolevulinic acid in a wide range of concentrations.

We describe a simple method for measuring delta-aminole-vulinic acid in urine without the need for the seldom-used but time-consuming internal-standard addition step. It combines the analytical procedure described by Tomokuni and Ogata [Clin. Chem. 18, 1534 (1972)] and a correction based on urine density to obtain, more rapidly and less expensively, results as accurate as those given by the Davis and Andelman [Arch. Environ. Health 15, 53 (1967)] chromatographic method.     

Plasma and white blood cell ascorbic acid concentrations in patients with bronchial asthma.

Plasma cholesterol, plasma and white blood cell ascorbic acid concentrations were estimated in 30 untreated, 32 salbutamol-treated patients with bronchial asthma and in 57 normal controls. Treated and untreated asthmatics had significantly higher plasma cholesterol but lower plasma and white cell ascorbic acid levels than normal controls. A negative correlation was found between white cell ascorbic acid level and plasma cholesterol concentration in both treated and untreated asthmatics. These findings are discussed.     

Multistix versus laboratory urinalysis in the detection of urinary tract infection.

1. Difficulty with the early recognition of infection is a problem when caring for patients in an extended care facility. 2. The ability to quickly differentiate between asymptomatic bacteriuria and actual infection in male extended care patients is useful for guiding antibiotic therapy. 3. The nurse-administered nitrite test proved reliable as an indicator or urinary tract infection.     

Validity of urinalysis and microscopy for detecting urinary tract infection in the emergency department.

This study assessed the validity of standard urinalysis, urinalysis for leucocyte esterase and nitrites, and urgent microscopy in the diagnosis of urinary tract infection (UTI) in 60 female patients with a triage diagnosis of UTI. There were 24 (40%) proven UTIs after culture. Simple urinalysis was sensitive for UTI (95.8%) but the positive predictive value was only 45.1%. The addition of leucocyte esterase and nitrite urinalysis testing did not improve the sensitivity, but if both of these were positive the positive predictive value improved to 100%. Urgent microscopy alone was sensitive (100%) but non-specific (38.9%). The specificity of the diagnosis improved to 94.4% for organism counts of >or=10/microl and to 88.9% for leucocyte counts of >or=50/microl. The negative predictive value of no detectable leucocytes on microscopy was 94.7%. Screening for UTI in the emergency department (ED) population is improved by the addition of leucocyte esterase and nitrite test. A positive urinalysis test for leucocytes and nitrites, or urinalysis positive at levels of >or=500 leucocytes or >or=5 g/l protein should confirm a clinical diagnosis of UTI. Urgent urine microscopy should be performed only if the above criteria are not met yet a minimum of one urinalysis result is positive.     

Identification and incidence of a urinary fragment of IgG.

Urine from some patients, when concentrated approximately three hundred fold and immunoelectrophoresed against anti-IgG, shows an unexpected additional precipitin line in the alpha-globulin region. This reaction has been shown to be due to the presence of a low molecular weight (approximately 20 000) fragment of the heavy chain of IgG. A retrospective examination of immunoelectrophoretic plates run over a period of five years has revealed that this fragment was present in 30 out of 110 patients.     

Medically significant concentrations of prostate-specific antigen in serum assessed.

We used the method of Rudolph et al. (Clin Chem 1988; 34:2031-8) to find information in the data from correlated determinations of acid phosphatase (PAP, EC 3.1.3.2; DuPont aca) and prostate-specific antigen (PSA, Hybritech). We described there how we assign medical decision limits for two or more correlated variables and convert the database to a binary coded message, allowing separation of a selected disease class with minimum error. The decision point, analogous to a percentile upper limit on the ordered values of each variable in the reference group, satisfies the maximum entropy constraints of reference, producing a minimum entropy for the binary coded patient database. We found maximum entropy decision points at PAP = 0.75 U/L and PSA = 22.8 micrograms/L. Patients with PSA values exceeding 22.8 micrograms/L had no benign prostatic disease except for five patients with benign prostate hyperplasia (BPH) with adjacent colon carcinoma (95.3), BPH with infarction (27.6), BPH (23.4) 28.1), or acute prostatitis (34.6). We consider PSA exceeding 22.8 micrograms/L as indicative of carcinoma of the prostate, stage C or D, in the absence of disconfirming evidence. Another decision value for PSA is 11.3 micrograms/L. This bounds the region between 11.3 and 22.8 micrograms/L, where the frequency of BPH is 1.5 times that for adenocarcinoma. At PSA less than 11.3 micrograms/L there is a high frequency of BPH. PSA concentration is not correlated with prostatic size (mass) or with prostatitis. A metastatic carcinoma is as likely to be nonprostatic as prostatic when the PSA concentration is less than 11.3 micrograms/L.     

Impacts of ascorbic acid and thiamine supplementation at different concentrations on lead toxicity in testis

BACKGROUND: Lead is a ubiquitous environmental and industrial pollutant that may have toxic effects on the male reproductive system. We explored the mechanism and examine the impacts of combined administration of ascorbic acid and thiamine at different levels on apoptosis in the testes of lead-exposed mice. METHODS: Seventy-five male mice were randomly divided into 5 groups (15 mice/group): control, lead-treated and vitamin-treated group (low, middle and high dose) with ascorbic acid (140, 420, 1260 mg/kg) and thiamine (10, 30, 90 mg/kg ) by oral gavage daily. All lead-exposed animals received 0.2% lead acetate in drinking water. DNA damage of testicular cells was assessed by SCGE; the levels of TGFbeta1 and caspase-3 were detected by immunohistochemistry; apoptotic cell was determined by TUNEL. RESULTS: Compared with control group, the expressions of TGFbeta1 and caspase-3, apoptotic index (AI) and DNA damage were increased significantly in lead-exposed group (P<0.05). After intervention of low and middle doses vitamin, the incidence of DNA damage and the number of apoptotic cells in testis were obviously lower than the lead-exposed group (P<0.05) and the impaired tissues were ameliorative. However, simultaneous supplementation of ascorbic acid and thiamine at the highest dose promoted testicular cell apoptosis via increased expressions of TGFbeta1 and caspase-3. CONCLUSIONS: The combination treatment with thiamine and ascorbic acid at lower doses effectively inhibited testicular cells from apoptosis by lead acetate, but higher doses could aggravate the testicular lesion.     

Individual variability in concentrations of urinary sulindac sulfide.

Among 70 patients with arthritis who were receiving satisfactory maintenance therapy with sulindac (300 to 400 mg daily), 64% had no detectable sulindac sulfide (active metabolite) in one to four random urine specimens. However, 36% had 1.0 to 7.8 (mean, 2.2 +/- 1.4) micrograms/ml sulindac sulfide in urine, similar to the therapeutically effective concentrations found in 24 concurrent plasma specimens (1.4 to 9.0 micrograms/ml). Ten patients had sulindac sulfide in only one or two of two to four urine specimens. Thus, 36% of the patients had pharmacodynamically significant concentrations of sulindac sulfide in urine, presumably capable of suppressing the cyclooxygenase pathway responsible for prostaglandin synthesis in the kidney and elsewhere. The findings suggest individual variability in the capacity for renal oxidation of sulindac sulfide to inactive metabolites, perhaps related to genetic or environmental factors or both. These findings may help to explain conflicting reports on the effects of sulindac on urinary prostaglandins and renal function.     

Performance of automated urine analyzers using flow cytometric and digital image-based technology in routine urinalysis

Abstract

The purpose of this study was to evaluate the analytical performances of Sysmex UF-5000 and Dirui FUS-200 and to compare the results with manual microscopy and between each other.

Two hundred fifty urine samples were analyzed for evaluation. Mid-stream specimens were studied sequentially using Dirui FUS-200 and Sysmex UF-5000, and also with manual microscopy within one hour. The physical and chemical components of urinalysis, and sediment results were investigated.

The precision results of the FUS-200 and UF-5000 for WBCs, RBCs, and ECs were acceptable. The both analyzers demonstrated good linearity (r?>?0.97), with no carry-over. The comparisons of FUS-200 and UF-5000 with manual microscopy for RBCs, WBCs, and ECs on 250 samples exhibited good agreement with little bias (R?>?0.780). Only, the moderate agreements were obtained for calcium oxalate for both analyzers (R?=?0.512, and 0.648, respectively). The sensitivities of the FUS-200 and UF-5000 were 75.8% and 86.8%, with specificities of 92.3% and 87.8% for WBCs, for RBCs the sensitivities were 91.1%, and 84.4% with specificities of 82.2%, and 89.6% for both analyzers. Kappa values of the UF-5000 were higher than FUS-200 for WBCs, RBCs, ECs, and calcium oxalate.

The FUS-200 and UF-5000 urine analyzers, are both accurate, very precise systems and can be safely used in clinical laboratories. However, due to the technological characteristics of the UF-5000 analyzer, its positive impacts on the morphologic recognition and enumeration of RBCs and WBCs should be taken into account, particularly in university hospital laboratories with high patient volumes.     

Development of a score based on urinalysis to improve the management of urinary tract infection in children

BackgroundThe need for reducing unnecessary antibiotic treatment is being emphasized in the management of urinary tract infections (UTI), a disease frequent in childhood. An ideal test should provide early diagnosis without the waiting times of urine culture, but even a simple test of exclusion could significantly improve patient management.MethodsWe evaluated the sensitivity, specificity, negative and positive predictive value of automated microscopy IRIS iQ200 combined with the dipstick analyses in children with suspected UTI. Multivariable logistic regression analysis was used to identify the set of variables that best predict positive culture results and develop a numerical risk score.ResultsOf 474 consecutive urine samples retrospectively analyzed, 69 were positive at urine culture with prevalence of infection of 14.6%. Parameters significantly associated with the presence of infection in multivariable analysis were age < 1 year (p < 0.001), leukocyte esterase ≥ 15 × 10^6/L (p < 0.001), number of small particles (ASP) ≥ 5500 × 10^6/L (p < 0.001) and bacteria ≥ 3 × 10^6/L (p = 0.01). The derived score ranged from 0 to 10, with higher values indicating higher risk of UTI. The area under the score ROC curve was 79% (95% CI 0.72–0.85), and was better than those of the individual urinary chemical and microscopic analyses.ConclusionsThis routine method could improve the management of UTI in children by early identifying patients with low probability of infection, for whom antibiotic treatment can be withheld until the results of urine culture become available.     

High incidence of erythromycin-resistant streptococci in Taiwan.

The activities of nine antimicrobial agents against 247 isolates of group B, C, F, and G streptococci and viridans group streptococci were studied by the broth microdilution method. Erythromycin resistance was found in 29.7, 41.7, 81.8, 23.5, and 53.3% of the strains of group B, C, F, and G streptococci and viridans group streptococci tested, respectively. Macrolides are not considered an optimal alternative to penicillin in the treatment of streptococcal infections, at least empirically, in Taiwan.     

Studies of blood ascorbic acid levels in acute myocardial infarction.

Fasting serum samples from 53 patients with an acute myocardial infarction were investigated for their vitamin C content during the first week of their illness. The vitamin C levels found were generally within the accepted normal limits. However, there were highly significant lower levels on the second to the fifth post-infarction days, as compared with those found on days six to eight.     

UF-500i与IQ200尿沉渣分析仪检测管型的比较和评价

目的比较UF-500i与IQ200尿沉渣分析仪在检测管型中的敏感度、特异度和影响因素。方法采用UF-500i、IQ200尿沉渣分析仪和离心沉淀显微镜法分别检测门诊肾病患者晨尿标本,以人工镜检法作为标准对两种仪器敏感度、特异度进行分析。结果480份晨尿标本中,UF-500i尿沉渣分析仪敏感度为97．1％（68／70）,特异度为76．6％（314／410）;IQ200尿沉渣分析仪人工修饰前后敏感度分别为91．4％、100％（64／70,70／70）,特异度为70．5％／98．3％（289／410,403／410）。结论UF-500i与IQ200尿沉渣分析仪具有较高的管型检测灵敏度,但假阳性率高,均需人工复核以提高准确性。