Random Serum Samples Research Articles

Hepatitis B Virus DNA in Unusual Serological Profiles of Hepatitis B Surface Antigen-Positive Sera

On the basis of a seroepidemiological survey of hepatitis B virus (HBV) infection conducted on 6208 random serum samples from four provinces of Thailand, we found 19 of 246 (7.7%) hepatitis B surface antigen (HBsAg)-positive samples with unusual serological constellations of HBV infection. Ten samples tested positive for HBsAg, anti-HBc (anti-hepatitis B core antibody), and anti-HBs (anti-hepatitis B surface antibody) markers (group I), 3 specimens were HBsAg and anti-HBs positive without detectable anti-HBc (group II), and the remaining 6 specimens showed only HBsAg (group III). In group I, 7 of 10 HBsAg-positive sera could be confirmed by HBsAg neutralization, yielding positive results for all samples. None of the group II sera were available in sufficient amounts for confirmation. In group III, five of six sera were confirmed by HBsAg neutralization, with four showing a positive reaction. HBV DNA was detected in 7 of 10 (70%) specimens in group I, in 1 of 3 (33.3%) specimens in group II, and in 3 of 6 (50%) specimens in group III. On the basis of HBsAg neutralization, HBV DNA was found in five of seven (71.4%) HBsAg-positive samples in group I and in three of four (75%) HBsAg-positive samples in group III, whereas the one confirmed HBsAg-negative sample in group III also remained negative for HBV DNA. Amino acid sequences were compared with those specifying the "a" determinant of the wild-type virus, particularly focusing on HBV-S protein variations between positions 110 and 160. Among 11 HBV DNA-positive sera, G145A was detected in 2 samples in group I, with the remaining samples identical to the wild-type virus. These unusual serological profiles may be due to the altered immune response of the host or to HBV variants.

Food Allergen Sensitization in Inner-City Children With Asthma

Purpose of the Study. To determine the prevalence of food allergen sensitization and its association with asthma symptoms and health care utilization in an inner-city asthma population. Study Population. Random serum samples were obtained from children (n = 544) aged 4 to 9 years (median: 6 years) with asthma living in inner-city areas enrolled in the National Cooperative Inner City-Asthma Study. Methods. Information regarding demographics, health history, medication use, health care utilization, and asthma symptoms was recorded on the basis of 3-month recall at baseline and at 3-month intervals for a period of 12 months. No information regarding food allergy diagnoses or reactions was obtained. Skin-prick testing to 13 environmental allergens was performed at enrollment in the National Cooperative Inner City-Asthma Study. The random serum samples were evaluated for specific immunoglobulin E (IgE) (UniCap System) to egg, milk, soy, peanut, wheat, and fish. On the basis of IgE levels, subjects were stratified into 4 groups: group 1, food-specific IgE levels that had >95% positive predictive value for food allergy; group 2, probable food allergy (IgE ≥ 0.7 kU/L); group 3, any sensitization (IgE ≥ 0.35 kU/L); and group 4, no evidence of food allergy (IgE < 0.35 kU/L). Results. There was a significant correlation between sensitization to foods and sensitization to aeroallergens, with sensitization to the highest number of aeroallergens correlating with sensitization to soy, wheat, and peanut. Forty-five percent of study patients were sensitized to at least one food (groups 1–3): 4% of the participants were categorized to group 1, 26% to group 2, and 14% to group 3. Fifty-five percent were not sensitized to any of the 6 foods (group 4). Food allergy to egg and peanut were associated with the highest specific IgE levels. Patients who were sensitized to at least one food had higher rates of hospitalization and steroid medication use. The food-sensitized groups required more medications in general, but this difference was not significant. Most group 1 children (96%) demonstrated sensitization to >1 food, with 25% of the patients sensitized to all 6 foods tested. Most group 2 patients (75%) and 19% of group 3 patients were sensitized to multiple foods. There was a significant increase in hospitalizations for asthma in children sensitized to >1 food. When specific foods were examined, a correlation between higher asthma morbidity and sensitization to fish or soy was noted. Conclusions. Food sensitization correlated with increased asthma severity in the study population. The prevalence of food allergy was not determined because of the nature of the study (anonymous serum samples and lack of blinded food challenges); however, on the basis of the study results, the authors predicted that inner-city children with asthma were more likely than the general population to have food allergy. The association of increased asthma morbidity with at least 1 food sensitization, and findings that patients with sensitization to multiple foods had significantly more asthma morbidity than those with single-food sensitization, suggest that food sensitization is a marker for increased asthma severity. Reviewer Comments. This study suggests that the prevalence of food sensitization, and possibly food allergy, is increased in patients with asthma and may be a useful marker for increased asthma severity. Health care providers should consider screening for food sensitization in patients with severe or poorly controlled asthma.

A Rare Case of Primary Amyloidosis, Presenting with Severe Pulmonary Hypertension and Bilateral Pleural Effusion.

Pulmonary arterial hypertension secondary to vascular deposition is a rare presentation of Primary Amyloidosis. The natural history of pulmonary hypertension and concomitant right-sided cardiac failure is not very well understood and is associated with a very short median survival. This syndrome is a marker of advanced Amyloidosis Persistent pleural effusion is another much rarer presentation of pulmonary involvement in Primary Amyloidosis and is secondary to pleural infiltration, which sometimes is difficult to distinguish from the cardiomyopathic causes. The incidence of pleural effusion in primary Amyloidosis is 1–2%. This syndrome also has a very poor prognosis, and has limited response to treatment, however, pleurodesis has been temporarily useful in some cases.Case report: A 74 year old African American female, non-smoker, with history of hypertension, who presented with shortness of breath and persistent productive cough and 18 pounds weight loss for the last six months. The initial chest x-rays showed bilateral pleural effusion and a transudate fluid on analysis. Cardiac workup for an atypical chest pain revealed moderate to severe pulmonary hypertension without myocardial infiltration on 2-D echocardiogram, and normal coronary arteries on cardiac catheterization. Extensive workup did not show any secondary cause of pulmonary hypertension, however, the patient gradually developed nephrotic range proteinuria and kidney biopsy showed infiltration of 10 nm fibrils, involving 3+ segmental mesangium, and 2+ segmental glomerular basement membranes. This was consistent with renal Primary Amyloidosis, AL Lambda type. A random urine and serum sample for immunofixation also revealed an M- spike of 23 mg/dl in gamma region. A concomitant bone marrow biopsy revealed presence of monoclonal IgG lambda plasma cell (CD38 bright) population, without any B-cell or T-cell markers.Conclusion: Pulmonary hypertension and pleural effusion are two rare and lethal presentations of pulmonary involvements in Primary Amyloidosis, and it should be considered in the differential diagnosis of any patient presenting with pulmonary symptoms. There is no definite treatment of these syndromes, although combinations of steroids and melphalan, along with colchicines, vincristine, adriamycin, and thalidomide have been used with minimum satisfactory outcomes. Autologous stem cell transplantation (SCT) provides the opportunity to give higher doses of chemotherapy and may be of benefit in some cases.

Gas Chromatographic–Mass Spectrometric Analysis for Measurement of p-Cresol and Its Conjugated Metabolites in Uremic and Normal Serum

p -Cresol (4-methylphenol; 108 Da) is a protein-bound solute retained within the body in renal failure (1). p -Cresol is of interest because it has several toxic effects in vitro (2)(3)(4)(5)(6) and clinical correlates have been demonstrated (7)(8). In the absence of external exposure (9), p -cresol originates uniquely from bacterial tyrosine fermentation in the large intestine (10). During passage through the colonic mucosa and liver, it is detoxified by conjugation processes (sulfation and glucuronidation) (11)(12)(13). Thus, one might expect to find p -cresylsulfate and p -cresylglucuronide in the serum, but reports on conjugated p -cresol in renal failure patients are scarce (14)(15)(16). Most techniques to deproteinize serum samples (e.g., heat and acidification) may also partially hydrolyze sulfate esters and glucuronide bonds. Hence, the “total” (i.e., protein-bound and unbound) and “unbound” p -cresol reported in most studies probably reflect both unconjugated and (part of the) conjugated forms of the solute (17)(18)(19)(20)(21). We determined the extent of desulfation and deglucuronidation by deproteinization with heat and acid followed by gas chromatographic–mass spectrometric (GC-MS) analysis (19) with p -nitrophenylglucuronide and p -nitrophenylsulfate as model substrates. We also calculated exact amounts of unconjugated p -cresol, p -cresylsulfate, and p -cresylglucuronide in serum of hemodialysis patients and healthy controls. Percentage desulfation and deglucuronidation by different methods (see below) was determined for random serum samples. Further analyses were performed on 9 serum pools from hemodialysis patients [n = 86; 49 male; mean (SD) age, 69.8 (1.5) years] and 5 serum pools from healthy controls [n = 29; 10 male; 31.0 (1.4) years; creatinine clearance, 87.1 (1.4) mL · min−1 · (1.73 m2)−1]. Serum pools were …

Further evidence for increased macrophage migration inhibitory factor expression in prostate cancer

BackgroundMacrophage migration inhibitory factor (MIF) is a cytokine associated with prostate cancer, based on histologic evidence and circulating (serum) levels.Recent studies from another laboratory failed to document these results. This study's aims were to extend and confirm our previous data, as well as to define possible mechanisms for the discrepant results. Additional aims were to examine MIF expression, as well as the location of MIF's receptor, CD74, in human prostatic adenocarcinoma compared to matched benign prostate.MethodsMIF amounts were determined in random serum samples remaining following routine PSA screening by ELISA. Native, denaturing and reducing polyacrylamide gels and Western blot analyses determined the MIF form in serum. Prostate tissue arrays were processed for MIF in situ hybridization and immunohistochemistry for MIF and CD74. MIF released into culture medium from normal epithelial, LNCaP and PC-3 cells was detected by Western blot analysis.ResultsMedian serum MIF amounts were significantly elevated in prostate cancer patients (5.87 ± 3.91 ng/ml; ± interquartile range; n = 115) compared with patients with no documented diagnosis of prostate cancer (2.19 ± 2.65 ng/ml; n = 158). ELISA diluent reagents that included bovine serum albumin (BSA) significantly reduced MIF serum detection (p < 0.01). MIF mRNA was localized to prostatic epithelium in all samples, but cancer showed statistically greater MIF expression. MIF and its receptor (CD74) were localized to prostatic epithelium. Increased secreted MIF was detected in culture medium from prostate cancer cell lines (LNCaP and PC-3).ConclusionIncreased serum MIF was associated with prostate cancer. Diluent reagents that included BSA resulted in MIF serum immunoassay interference. In addition, significant amounts of complexed MIF (180 kDa under denaturing conditions by Western blot) found in the serum do not bind to the MIF capture antibody. Increased MIF mRNA expression was observed in prostatic adenocarcinoma compared to benign tissue from matched samples, supporting our earlier finding of increased MIF gene expression in prostate cancer.

Food allergen sensitization in inner-city children with asthma

Asthma continues to be an increasing cause of morbidity in the pediatric population, and studies have shown an association between food sensitivity and asthma. We investigated the degree of food allergen sensitization in inner-city patients with asthma. Five hundred four random serum samples from the National Cooperative Inner City Asthma Study were evaluated for specific IgE (UniCap) to 6 common food allergens (egg, milk, soy, peanut, wheat, and fish). Statistical analyses were performed to determine food sensitization prevalence and its association with asthma morbidity. Forty-five percent of patients had evidence of sensitization (food-specific IgE > or = 0.35 kU/L) to at least 1 food. Nineteen percent had IgE levels at > or = 50% positive predictive value for clinical reactivity to at least 1 food, with 4% of patients having levels > 95% positive predictive value for food allergy. Children sensitized to foods had higher rates of asthma hospitalization (P < .01) and required more steroid medications (P = .025). Sensitization to foods also correlated with sensitization to more indoor and outdoor aeroallergens (P < .001). Food allergen sensitization is highly prevalent in the inner-city population with asthma, and it is associated with increased asthma healthcare and medication use. Therefore, food allergen sensitivity may be a marker for increased asthma severity.

Seroprevalence and comparison of isolates of endometriotropic bovine herpesvirus-4.

Sixty-eight cases of suppurative, ulcerative endometritis associated with Bovine Herpesvirus-4 (BHV-4) in postparturient dairy cows (62 Holsteins and 6 Jerseys, mean age 4.2 years) were confirmed by a combination of histopathology, fluorescent antibody assays, electron microscopic evaluation of uterus, and polymerase chain reaction (PCR). All cases occurred in the 3- to 28-day postpartum period, and histologic lesions among various cows were consistent when compared with postpartum interval. The endometrial lining epithelium was necrotic and ulcerated from 3 to 7 days postpartum, with only mild inflammation in the lamina propria and submucosa. From 1 to 4 weeks postpartum, the ulcers were confluent to diffuse. Epithelium was replaced by fibrinonecrotic, suppurative mats, resulting in severe bacterial pyometra by day 24. Seroprevalence to BHV-4 in one dairy with a history of 18 mortality cases was 36% (107 of 296). In a random sample of 8 cows from this herd, none had serologic titers in blood sampled 2 weeks prepartum, but 3 of 8 seroconverted with significant titers of 1:8 to 1:16 at 2 weeks postpartum. By 10 weeks postpartum, all 8 cows returned to negative serologic status. Two of 6 cats from the premises also had positive titers. Random serum samples taken from 480 dairy cattle at sale barns indicated 76 (16%) were positive by serum neutralization. Clinical signs, postparturient timing, and histologic lesions were very similar to those previously reported in Belgium with BHV-4. But sequence analysis of PCR products of the glycoprotein B region of 4 separate field isolates of endometriotropic BHV-4 suggests these field isolates were more closely related to the North American nonvirulent strain DN-599 than to the endometriotropic European strain V.

Serum vascular endothelial growth factor is elevated in cystic fibrosis and decreases with treatment of acute pulmonary exacerbation.

Chronic bacterial infection and neutrophilic inflammation characterize cystic fibrosis (CF) pulmonary disease. In many disorders, inflammation and angiogenesis are codependent phenomena. We previously noted excessive angiogenesis in CF tissues and elevated vascular endothelial growth factor (VEGF) in random serum samples from subjects with CF. To further explore this finding, we measured serum VEGF in 38 subjects with stable CF and in 25 subjects with other pulmonary diseases. Mean VEGF was elevated in both groups compared with reference values, but it was higher in CF: 403 +/- 280 versus 255 +/- 169 pg/ml, p = 0.02. VEGF was negatively correlated with FEV(1) in CF, r = -0.51, p = 0.007. To assess the effect of airway infection on VEGF, 10 subjects with CF were studied before and after intravenous antibiotic therapy for pulmonary exacerbation. VEGF levels decreased with antibiotic therapy, from 537 +/- 220 to 259 +/- 176 pg/ml, p = 0.001. We conclude that circulating VEGF is increased in subjects with CF and other inflammatory pulmonary disorders. In CF, VEGF elevation is related to airway infection. We speculate that increased circulating VEGF is related to chronic inflammation, which is robust in CF. Elevated circulating VEGF may result in tissue angiogenesis, furthering the progression of pulmonary disease.

Utility of tumor marker CA 72.4 in patients with chronic renal failure.

The tumor marker CA 72.4 is composed of two monoclonal antibodies, B 72.3 and cc49, which detect the glycoprotein TAG 72 present in tumor cells. The levels of CA 72.4 may be modified depending on the route of excretion of the antigen TAG 72. The objective of this study was to evaluate the behavior of CA 72.4 in healthy subjects and to assess the influence of chronic renal failure (CRF) on the levels of this tumor marker. Random serum samples were collected in 181 individuals (148 healthy volunteers and 33 patients with CRF) and 214 determinations of CA 72.4 were performed. We also performed 66 determinations of plasma creatinine. In healthy subjects the cutoff value of CA 72.4 was established at 3 U/mL, with a sensitivity of 53% and a specificity of 85.8%. In the CRF patients we found no statistically significant differences when we compared the values of CA 72.4 predialysis and postdialysis (p = 0.197). However, a statistically significant difference was found in the plasma creatinine levels (p < 0.001). Chronic renal failure does not affect the result of CA 72.4 determinations; this tumor marker may therefore be useful in the monitoring of patients with cancer, independent of their renal function.

A simple, rapid and reliable enzyme-linked immunosorbent assay for the detection of bovine virus diarrhoea virus (BVDV) specific antibodies in cattle serum, plasma and bulk milk

To detect Bovine Virus Diarrhoea Virus (BVDV)-specific antibodies in cattle serum, plasma and bulk milk, a simple, reliable and rapid blocking ELISA ("Ceditest") has been developed using two monoclonal antibodies ("WB112" and "WB103") directed to different highly conserved epitopes on the non-structural peptide NS3 of pestiviruses. The test can be performed at high reproducibility using undiluted samples. In testing 1000 field serum samples, the ELISA showed a specificity and a sensitivity relative to the virus neutralization test of 99% and 98%, respectively. The blocking ELISA is able to detect specific antibodies in serum obtained 12 days after an acute infection and in serum of vaccinated and challenged animals. A frequency distribution diagram, obtained by testing almost 1800 random Dutch field serum samples, showed a clear separation between a negative population (maximum frequency of the % inhibition at −5%) and a positive population (maximum frequency of the % inhibition at 95%). Based on these data, the prevalence of seropositive animals was 65% (95% confidence interval: 63%–67%). By exchanging plasma- and bulk milk samples between two laboratories (The Netherlands and Denmark), a good overall agreement was found between results obtained with the Ceditest and those obtained with the Danish blocking ELISA as used in the Danish BVDV eradication programme. The results indicate that BVDV infections can reliably be diagnosed by the Ceditest ELISA and that the test is suitable for use in large scale screening and eradication programmes.

Evaluation of the analytical performances of a new fully automated commercial immunonephelometric assay for lipoprotein(a).

Several commercial methods have been proposed for lipoprotein(a) (Lp(a)) measurements over the past decades. However, only a few of them appear completely suitable in terms of analytical performance, costs and practicability. We evaluated the analytical performance of a new commercial fully automated immunonephelometric assay for Lp(a) measurements on the IMMAGE Immunochemistry System. Mean within- and between-run coefficients of variation were 2.7% (range 1.2-4.7%) and 3.8% (range 1.8-7.9%), respectively. The linearity of the assay was confirmed up to 102 mg/dl and the deviation from the expected values did not exceed 4% (mean deviation: 1.9%). Moreover, the relative non-linearity was acceptable, ranging from 1.4% to 1.6% and hence constantly lower than the 2.5% upper limit. Since there is no reference method for Lp(a) measurements, 100 routine random serum samples measured by the IMMAGE Immunochemistry System immunonephelometric assay were further compared with two other commercial immunonephelometric assays (Array LPA immunonephelometric assay and BNA Latex-Enhanced Lp(a) nephelometric assay). Non-parametric regression and relative Spearman's correlation coefficients were satisfactory, (y=1.009x - 1.38; r=0.998 IMMAGE Immunochemistry System vs. Array LPA and y=0.922x - 0.40; r=0.989 IMMAGE Immunochemistry System vs. Behring Nephelometer Analyzer (BNA) Latex Lp(a) assay). On the basis of the results of the present evaluation we conclude that the analytical performance and the main technical features of the IMMAGE Immunochemistry System immunonephelometric assay make it a suitable method for Lp(a) measurement in clinical laboratories.

Basal serum pancreatic polypeptide is dependent on age and gender in an adult population

This study is the first epidemiologically based study of basal levels of serum pancreatic polypeptide (s-PP). The basal level of serum PP has become a field of interest mainly due to the role of PP as an endocrine tumour marker, and as a marker of pancreatic neuroendocrine function after pancreas transplantation and in the case of diabetic autonomic neuropathy. The study population consisted of primarily Caucasian adults representative of a general population living around Copenhagen. Serum pancreatic polypeptide was measured in random serum samples from fasting persons (n=623), aged 25-64 y, using a monospecific radioimmunoassay. Fasting serum pancreatic polypeptide depended on age and gender. The results demonstrated that fasting pancreatic polypeptide levels increase exponentially with age. Fitted separately for each sex, basal serum pancreatic polypeptide was found to increase by approximately 3% per year of age. Males had higher concentrations of pancreatic polypeptide in serum compared to age-matched females. Normal range and 95% reference intervals are given. The lower limit for the reference interval of the normal range was close to detection limit. We conclude that discrepancies among earlier reports on the fasting levels of serum pancreatic polypeptide are most likely due to lack of adjustment for age and gender. Thus, variation due to age and gender should be considered in evaluating fasting levels of serum pancreatic polypeptide. Whether similar considerations are important when evaluating stimulated serum pancreatic polypeptide levels remains to be elucidated.

Overexpression and purification of a recombinant chimeric HIV type 2/HIV type 1 envelope peptide and application in an accelerated immunobased HIV type 1/2 antibody detection system (AIBS): a new rapid serological screening assay.

A chimeric HIV-2/HIV-1 envelope sequence containing an immunodominant region of HIV-2 gp36 and the corresponding region of HIV-1 gp41 was constructed and overexpressed in Escherichia coli. The recombinant product (rp21/18) was purified and applied in a novel antibody-screening assay. Characteristics in the design of this new principle are as follows: (1) the overall assay time is about 30 min; (2) the assay procedure includes three manipulation steps; and (3) the test shows a reliable performance with respect to sensitivity and specificity. The diluted serum sample and the protein G-horseradish peroxidase conjugate are added simultaneously into a coated (hybrid antigen HIV-1/2) and blocked microtiter plate well. The in-batch incubation of serum sample with protein G-horseradish peroxidase saves two manipulation steps that are normally necessary in the five-step procedure of a classical ELISA. AIBS was evaluated with commercially available seroconversion panels and with random negative serum samples from a blood bank. Seroconversion results demonstrated that AIBS has equivalent sensitivity to ELISAs and the third generation assays. The specificity was determined on a total blood donor population of 5012 (Red Cross Vienna, Austria). The repeat reactive rates for donor population were 0.02%. AIBS represents a general immunometric system (not only HIV antibodies). The entire assay procedure of AIBS evaluated for HIV-1/2 screening, including result reporting, can be performed automatically by several commercially available systems. Depending on these systems AIBS is potentially useful in laboratories or blood banks that have both high- and low-volume testing.

Normal ranges for immunochemiluminometric gonadotropin assays

Objective: We sought to establish normative data for spontaneous and gonadotropin-releasing hormone (GnRH)-stimulated serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels measured by new immunochemiluminometric assays (ICMA) in children and adolescents. Methods: Random serum samples were obtained from 375 normal subjects (0.1 to 17.7 years, 230 female subjects). Intravenous GnRH stimulation tests were performed in 41 normal subjects (4.8 to 18 years, 20 female subjects). Normal ranges were calculated by age and Tanner stage. Immunochemiluminometric assays of LH and FSH concentrations were compared with levels obtained by a sensitive immunofluorometric assay and a less sensitive radioimmunoassay. Results: Random gonadotropin concentrations in normal children followed the pattern of transient elevation in infancy, low but measurable prepubertal levels, and markedly increased values at puberty. Spontaneous LH levels were higher in male infants but were not statistically different in boys and girls after infancy. Mean prepubertal LH was 0.04 ± 0.04 IU/L (n = 66), rising 100-fold during puberty. Spontaneous FSH levels were much higher than LH values, were higher in female infants, and rose threefold at puberty. Peak GnRH-stimulated LH was identical in prepubertal boys and girls (1.8 ± 1.3 IU/L, n = 17) and increased 20-fold at puberty. Mean peak GnRH-stimulated FSH was highest in prepubertal female subjects. Luteinizing hormone values measured by ICMA and immunofluorometric assay were highly correlated, but radioimmunoassay levels diverged markedly from ICMA levels at lower concentrations. Because absolute levels were higher, FSH values correlated adequately in the three assays throughout the normal physiologic range. Conclusions: Measurement of LH by ICMA is much more sensitive than older assay methods. Spontaneous LH can be accurately measured by ICMA to the very low levels present in normal prepubertal children, providing a potentially important biochemical discriminator of pubertal status. An ICMA GnRH-stimulated LH level greater than 5 IU/L is suggestive of maturing gonadotropin secretion. The ICMA LH assays provide significant enhancement in sensitivity; these assays should be used when levels may be low, and by their accuracy may reduce the time and expense of testing procedures. (J P EDIATR 1995;127:40-6)

Reference limits of apolipoprotein A-I and apolipoprotein B using an IFCC standardized immunonephelometric method.

An important collaborative study organized by the IFCC enabled the selection of international reference materials and the standardization of commercially available methods by the use of common calibrators. In this paper, we report the reference limits of apolipoprotein A-I and apolipoprotein B in a selected healthy French population. The apolipoprotein measurements were performed on BNA Behring using reagents and protocols supplied by the manufacturer: the standard sera were calibrated using the IFCC-WHO reference preparations (SP1 and SP3). In addition, the apolipoprotein B protocol was modified by the addition of a supplementary reagent to reduce the interference by lipaemic samples on immunonephelometric measurement. In a sample of 115 random serum samples, there was a decrease in mean concentration between non-standardized and standardized methods: -4.8% for apolipoprotein A-I and -4.7% for apolipoprotein B. The reference limits for apolipoprotein A-I are unaffected by gender between 4 and 14 years, thereafter vary with age and gender until 40 years and with gender alone between 40 and 60 years. For apolipoprotein B, the variation with gender is only significant between 30 and 49 years.

Clinical evaluation of a serological assay using a monoclonal antibody (TB72) to the 38 kDa antigen of Mycobacterium tuberculosis

We examined an enzyme-linked immunosorbent assay (ELISA) modification of a radioimmunoassay, using the TB72 monoclonal antibody, as a serological test for tuberculosis in a clinical setting. Sera were obtained from 238 patients with suspected pulmonary tuberculosis, 30 patients treated for tuberculosis, 28 contacts, and 480 random samples from inpatients. Antibody levels were measured as the dilution of serum causing 50% inhibition of binding of the TB72 monoclonal antibody, which binds to an epitope of the 38 kDa antigen specific to the Mycobacterium tuberculosis complex, a positive titre being > 3. Positive antibody titres were present in 21 out of 25 (84%) patients with smear-positive and 22 out of 27 (82%) patients with smear-negative, culture-positive tuberculosis, and 37 out of 41 (90%) patients successfully treated for tuberculosis but without bacteriological confirmation of disease. Three out of 82 (4%) patients with a firm alternative diagnosis to tuberculosis gave a positive result. Serological tests were negative within 2.5 yrs of successful treatment. Patients without a definite diagnosis one year after tuberculosis had been suspected, and those who had received inadequate treatment for tuberculosis, were frequently positive (21 out of 31 and 21 out of 32, respectively). Positive tests concurred with tuberculin reactivity in 8 out of 11 contacts given chemoprophylaxis. Screening of 480 random serum samples gave 22 positive titres, 16 of which were not associated with tuberculosis; none of these 16 had an antibody titre > 10. We conclude that the TB72 test provides additional information in the diagnosis and treatment of tuberculosis. Antibody titres > 10 suggests active tuberculosis; titres of 3-10 merit observation.

Comparison of the enzyme‐linked immunosorbent assay (elisa), haemagglutination inhibition test and agar gel precipitation test for detection of antibodies to avian infectious bronchitis virus

The immune response after vaccination with infectious bronchitis virus (IBV) under field conditions was measured by the ELISA, haemagglutination-inhibition (HI) and agar-gel precipitin (AGP), tests. Vaccinations were performed in three flocks and one experimental group via the drinking water with the vaccine strains H 120 and H 52. In each flock 40 random serum samples were taken every 2 weeks and tested individually. In the experimental group blood samples were collected every week from each of the 10 chickens. The primary vaccination with H 120 resulted in a rapid increase of antibody titre as detected by ELISA followed by a slow decrease over the next few weeks. By the HI and AGP tests no antibody responses could be seen after this primary vaccination. Revaccination with the H 52 strain provoked a further increase in ELISA titres. In the experimental group, and in flock W, a similar increase occurred by the HI test and precipitating antibodies appeared. The formation of HI antibodies in flock T (nipple waterers) was somewhat retarded and precipitating antibodies were just detectable. In flock F revaccination did not result in the immediate production of HI and AGP antibodies. However, 6 weeks after revaccination a significant rise in ELISA, HI and AGP antibodies was observed, probably as the result of a field infection. It was demonstrated that, based on the higher sensitivity, the ELISA test is more suitable than HI and AGP to monitor antibody responses to vaccination against infectious bronchitis. Strain specificity in the HI test is discussed as a reason for its failure to detect antibodies after primary vaccination with the highly attenuated vaccine strain H 120.

Serum fructosamine concentration as measure of blood glucose control in type I (insulin dependent) diabetes mellitus.

Serum fructosamine activity was studied in 42 patients with type I (insulin dependent) diabetes mellitus and 30 non-diabetic volunteers as an index of blood glucose control. There was a significant correlation both between fructosamine and glycosylated haemoglobin values (r = 0.82) and between fructosamine and the fasting C peptide concentration (r = -0.81). Test results in 14 of the diabetics reflected the mean plasma glucose concentration calculated from 25 serial estimations in a single 24 hour period (r = 0.75; p less than 0.01) but not the mean amplitude of glycaemic excursion (r = 0.23; p greater than 0.05). Fructosamine concentrations measured in these multiple blood specimens did not change significantly throughout the day (mean coefficient of variation 4.1%) despite wide variability of the respective plasma glucose concentrations (mean coefficient of variation 36.2%). It is concluded that a single random serum sample analysed for fructosamine concentration provides a simple and reliable assessment of glucose homoeostasis in patients with type I diabetes mellitus.

Haptoglobin polymorphism in Egyptians.

In 505 random serum samples from unrelated healthy genuine Egyptians, haptoglobin 2-2 phenotypes were most prevalent, though statistically were as common as haptoglobin 2-1 phenotypes. High inbreeding with average inbreeding coefficient of 0.0145 explains the deviation of Egyptian haptoglobin phenotypes from the Hardy-Weinberg equilibrium.

Estimation of serum ascorbic acid in patients and the effect of ascorbic acid and its oxidation products on SMA 12/60 parameters

A revised automated method was used to determine ascorbic acid in one hundred random patients' serum samples, and a range of concentrations between 0.7--2.5 mg/dl (0.040--0.141 mmol/L) was found. Volunteers taking a 2000 mg dose of ascorbic acid orally were found to have attained serum levels of ascorbic acid less than 2.8 mg/dl (0.159 mmol/L) in a period of 120 minutes. Five and ten mg of ascorbic acid or its oxidation products were added to 100 ml of pooled serum and the following components were estimated on our SMA 12/60: calcium, inorganic phosphorus, glucose (Trinder), urea, uric acid (phosphotungstate), total protein, albumin (BCG), total bilirubin, cholesterol (enzymatic), alkaline phosphatase, LDH (UV), and SGOT (UV), as well as glucose on a separate Technicon AA-II analyzer (ferricyanide method). With the 10 mg amounts the following analyses were found to be influenced significantly: glucose (Trinder), glucose (ferricyanide), uric acid, cholesterol and total bilirubin; the last of these by the oxidation products only. However, deviations produced for all but one of these tests were less than their allowable limits of error and were therefore considered to be clinically insignificant. The exception was the enzymatic glucose method of Trinder which was sensitive to a plasma ascorbic acid level as low as 2.0 mg/dl (0.114 mmol/L).