Female genital schistosomiasis due to Schistosoma haematobium. Clinical and parasitological findings in women in rural Malawi

A total of 51 women with urinary schistosomiasis haematobium were examined in order to identify diagnostic indicators for female genital schistosomiasis (FGS). Patients were selected at random from the outpatient department of the Mangochi District Hospital, Malawi. The medical histories were recorded according to a pre-designed questionnaire and the women were subjected to a thorough gynaecological examination including colposcopy and photographic documentation of lesions. Microscopy of genital biopsies revealed that 33 of the 51 women had S. haematobium ova in cervix, vagina and/or vulva in addition to the presence of ova in urine. The most sensitive diagnostic procedure was beside microscopic examination of a wet cervix biopsy crushed between two glass slides, which revealed 25 of the 33 genital infections. There was a significant correlation between the size of genital lesions and the number of ova counted per mm2 of crushed tissue. Women with FGS had significantly more tumours in the vulva than women with schistosomiasis limited to the urinary tract. Most of the observed genital pathology could easily be identified by the naked eye, but colposcopic examination yielded valuable additional information like the demonstration of neovascularisation around cervical sandy patches. Few of the symptoms previously regarded as indicators for FGS could be linked to the presence of schistosome ova in genital tissue. Husbands of infertile women with FGS had children with other women significantly more often than husbands of women who only had urinary schistosomiasis. This, together with the finding that the majority of the divorced women had FGS, indicates that the manifestation of this disease may have implications for the marital and sexual life of the affected women.     

Vaginal topography does not correlate well with visceral position in women with pelvic organ prolapse

The objective was to determine whether vaginal topography accurately predicts the location of the pelvic viscera on fluoroscopy in women with pelvic organ prolapse. Eighty-nine women undergoing preoperative evaluation for reconstructive pelvic surgery at a tertiary care referral practice formed the study population. Each woman completed a comprehensive urogynecologic history and physical examination, which included a quantified (POP-Q) assessment of her vaginal topography, as described by Bump et al. In addition each woman underwent pelvic floor fluoroscopy (PFF). Visceral sites were selected which corresponded clinically to the vaginal sites measured by the POP-Q. The most dependent portion of the bladder, small intestine, rectum and urethrovesical junction was measured. Twenty-five (28%) women had stage II prolapse, 34 (38%) had stage III prolapse, and 28 (32%) had stage IV prolapse. The remaining 2 women were symptomatic, with stage I prolapse. For the entire study population there was no correlation between the fluoroscopic position of the small bowel and/or rectum and any apical or posterior wall POP-Q site (C, Ap or Bp). There was no correlation with the fluoroscopic position of the UVJ at rest or with straining and the corresponding POP-Q site (Aa). The fluoroscopic position of the most dependent portion of the bladder correlated only modestly with the upper (Ba, rho = 0.51) and lower Aa, rho = 0.68) anterior vaginal wall POP-Q sites. In women without prior surgery (n = 33) there was only modest correlation between the fluoroscopic position of the bladder and the corresponding POP-Q site (Aa, rho = 0.71). In this unoperated subpopulation there was no correlation with PFF and any other POP-Q site. In women who had undergone prior hysterectomy (n = 25) or hysterectomy with anterior and/or posterior colporrhaphy (n = 17), there was only a modest correlation of the most dependent portion of the bladder and the upper anterior vaginal wall site (Bb, rho = 0.67 and rho = 0.55, respectively). It was concluded that vaginal topography does not reliably predict the position of the associated viscera on PFF in women with primary or recurrent pelvic organ prolapse.     

Current diagnostic and therapeutic management of CNS metastasis in childhood primitive neuroectodermal tumors and ependymomas

The aim of this study was to determine the presence and concentration of immunoreactive eosinophil cationic protein (ECP) and eosinophil protein X (EPX) in human amniotic fluid at term and assess labour-associated changes in their mean concentrations. In addition, ECP and EPX content in term amnion, choriodecidua and placenta obtained before and after labour and delivery was established. Immunoreactive ECP and EPX were identified in all samples of amniotic fluid (n=47) and gestational tissue (n=60) assayed. EPX was quantitatively more abundant than ECP in both amniotic fluid and gestational tissues. In amniotic fluid, ECP and EPX concentrations increased 8-fold (P<0.02) and 1.5-fold (P<0.02), respectively, with labour onset. In gestational tissues, a labour-associated change in tissue content was only identified for ECP in choriodecidua, which increased 1.9-fold with labour and delivery (P<0.01). The labour-associated increase in amniotic fluid concentrations of ECP and EPX demonstrated in this study is consistent with the well-characterized role of these proteins in inflammatory reactions. It remains to be established whether the observed increase in ECP and EPX amniotic fluid concentrations is an epiphenomenon of labour onset or is involved causally in this process.     

Cerebrospinal fluid levels of biopterin, nitric oxide metabolites, and immune activation markers and the clinical course of human cerebral malaria

Cerebrospinal fluid samples from 130 children who presented with cerebral malaria were investigated to elucidate the impact of biopterin production, NO formation, and local immune activation on the clinical course of this disease. Biopterin levels were significantly lower in patients who were in a deeper coma (P = .02). Cerebrospinal fluid concentrations of NO were significantly higher in children who died than in survivors (P = .037); however, this was not the case for macrophage activation markers, neopterin, and soluble tumor necrosis factor receptor p75 (sTNFR-75). Biopterin, neopterin, and sTNFR-75 but not NO concentrations were significantly related to each other. Low biopterin levels in deep coma are compatible with an impaired local Th1 response, but the low levels could also be due to the scavenging of radicals or to decreased neurotransmitter synthesis. Local production of NO, most likely by nonimmune mechanisms, may be detrimental in cerebral malaria; however, this appears not to be the case for local Th1-mediated immune pathways.     

Impairment of the mucosal immune system: IgA and IgM cleavage detected in vaginal washings of a subgroup of patients with bacterial vaginosis

The integrity of the immunoglobulins in vaginal washings of patients with bacterial vaginosis was examined to answer the question of the lack of immune response against Gardnerella vaginalis cytolysin. Clinically diagnosed patients (n=100) were recruited and their vaginal washings examined by Western blotting. Many showed IgA and IgM partially or extensively degraded. According to the degradation pattern, the patients were subdivided into 4 subsets, from intact (score 0) to completely degraded IgA (score +3). Statistical analysis of the data showed a correlation between IgA degradation and absence of immune response to G. vaginalis cytolysin. The extent of IgA degradation correlated also with the sialidase (but not with the prolidase) activity level. All women showed intact IgG and human serum albumin and no trypsin-like activity. Patients with bacterial vaginosis having high sialidase activity and extensive IgA degradation in their secretions could incur more dangerous infections and adverse pregnancy outcomes.     

Performance of the IgG avidity test in patients with cytomegalovirus disease

T-cell subsets and soluble factors of immune system activation are increasingly used as biologic markers of disease and predictors of disease progression. For example, changes in CD4 cells and CD4:CD8 ratio, sIL-2R, B2M, neopterin, and IgA have been used in predicting AIDS onset and progression. We examined the temporal variability of T-cell subsets, monocytes, natural killer cells, B cells, immunoglobulins, soluble interleukin-2 receptor (sIL-2R), neopterin, and beta-2 microglobulin (B2M) among 135 adults tested at two time points approximately 3 months apart. The purpose of the study was two-fold: (1) to assess the stability of these measures at two points in time, and (2) to investigate which parameters tend to track together over time, i.e., show significant longitudinal correlation. Mean population values for these immunologic parameters remained remarkably stable over the 3-month period. However, individual subjects exhibited significant temporal variability for many parameters. Unlike observations in patients with AIDS, changes in immunoglobulins and other soluble factors were not significantly correlated with changes in cellular subsets over the same period. However, change in B2M was correlated with change in neopterin (r = .35, p < or = .0001), and change in IgA was correlated with changes in IgG and IgM (r = .44, r = .54, P < or = .001 for both). Characterizing this temporal variability in a healthy population provides important information for researchers applying these tests in clinical and epidemiological studies.     

Immunological investigations in vaginal mycoses

In 42 women with chronically recurrent and 20 women with acute Candida albicans vulvovaginitis, as well as 14 women with Candida glabrata vaginitis, the following investigations were carried out: determination of protein content and secretory immunoglobulin A (sIgA) in the cervicovaginal secretion by a self-modified ELISA technique; determination of immunocells and cellbound IgA in the cervicovaginal secretion by immunofluorescence and nephelometric analysis of IgA in the serum. The results were compared with those of 77 pre-menopausal non-pregnant women with or without intake of anti-ovulants, 17 healthy pregnant women and four hysterectomised pre-menopausal women. Due to inflammation, women with acute and chronically recurrent Candida albicans vulvovaginitis had a higher protein content in the cervicovaginal secretion than healthy women. However, the content of secretory IgA was not increased but even slightly decreased in chronic cases. The number of macrophages and granulocytes in the vaginal content was not increased compared with healthy patients. In only a few cases was IgA detected on yeast cells and in the cervicovaginal secretion by fluorescence microscopy. In chronically-relapsing vaginal candidosis, the frequency of the serotype B of C. albicans was strikingly high. Women with Candida glabrata vaginitis showed lower values of secretory sIgA in the vaginal secretion compared with healthy patients as well as women with vaginitis caused by C. albicans. However, like healthy women, they had normal protein values in the cervicovaginal secretion and also lower values of IgA in the serum compared with women of C. albicans vulvovaginitis patients. Macrophages and granulocytes were demonstrable in the cervicovaginal secretion just as in healthy persons. Women with C. glabrata vaginitis showed a more conspicuous, although not a significantly more frequent, binding of IgA to budding cells demonstrated by fluorescence microscopy than women with C. albicans.     

Surgical treatment of a lateroradicular lesion on an invaginated lateral incisor (dens in dente)

In order to identify the relationship between eosinophil activation in Henoch-Sch?nlein purpura (HSP) and IgA nephropathy, serum eosinophil cationic protein (ECP) was analyzed in both conditions. The soluble interleukin-2 receptor (sIL-2R) was also analyzed. The levels of ECP were significantly higher in HSP patients (mean 9.7 +/- 1.8 microg/l) than in a control group (mean 4.6 +/- 0.7 microg/l). When the HSP patients were classified into two groups, one with normal urine and one with abnormal urine, the latter showed higher levels of ECP than the former. Levels of ECP were not significantly higher in IgA nephropathy patients than in a control group. The sIL-2R levels were elevated in the serum of HSP and IgA nephropathy patients compared with controls. In conclusion, eosinophil activation may be involved in the pathogenesis of HSP but not in IgA nephropathy.     

An evaluation of a measure of the proportion of the treatment effect explained by a surrogate marker

Time-dependent markers, such as CD4 and viral load, are potential surrogate markers in AIDS clinical trials. A critical issue with surrogate markers is whether changes in these markers explain the beneficial effect of treatment on the real end point of the clinical trial. A statistic to measure the proportion of the treatment effect explained by the surrogate is p(FGS) = 1 - gamma/alpha, where alpha is the treatment effect coefficient in a Cox model and gamma is the treatment effect coefficient from a time-dependent Cox model adjusted for the marker. In this article we evaluate the statistical properties of p(FGS). Using a Monte Carlo study we show that the statistic is not well calibrated, because it can fall outside the range zero to one, even in very large samples. In the simulation study we consider situations where the time-dependent marker is measured with error at a fixed number of times. We show that a method of fitting a time-dependent Cox model involving smoothing the marker reduces the bias in the estimate of p(FGS) compared with the standard method of using the current or last observed marker value. We also show that the estimate of p(FGS) has considerable variability and can have wide confidence intervals. We conclude that p(FGS) is only likely to be useful in large trials with a strong treatment effect. The methods are illustrated using CD4 counts from an AIDS clinical trial of zidovidine versus placebo.     

Monitoring eosinophil activation and liver function after liver transplantation

BACKGROUND: Portal tract eosinophil infiltration and an increase in the blood eosinophil count (EOS) have been shown to be specific markers of liver allograft rejection. The graft eosinophil infiltration is associated with the local release of eosinophil cationic protein. Therefore, serum eosinophil cationic protein concentration (ECP) is a potential marker for acute allograft rejection. We investigated the chronological relationship among and diagnostic value of serial changes in EOS, ECP, and liver function tests (LFTs) following liver transplantation. METHODS: EOS, ECP, serum alpha-glutathione S-transferase concentration, and conventional LFTs were measured in serial samples collected over the first 3 postoperative months following 58 liver transplants. The diagnostic potential of each test, alone or in combination, was reviewed over the entire follow-up period. RESULTS: EOS and ECP increased at a median period of 3.5 and 4 days, respectively, before the diagnosis of acute rejection, and this increase was significantly earlier than the corresponding changes in LFTs (P<0.05). There was a significant correlation between the day of the first increase in EOS and alpha-glutathione S-transferase (rs=0.535; P=0.009) and EOS and alanine transaminase (rs=0.629; P=0.004). The optimum combination of tests for the diagnosis of acute rejection was an increase in both EOS and GST with a predictive efficiency of 84%. CONCLUSIONS: Increases in EOS and ECP are early indicators of acute liver allograft rejection and precede evidence of hepatocellular damage. However, an increase in ECP was also frequently associated with infection. Therefore, we recommend the regular monitoring of EOS in conjunction with routine LFTs after liver transplantation as an aid to the early diagnosis of acute rejection.     

Evaluation of eosinophilic cationic protein levels in patients with eosinophilic pneumonia

We investigated the significance of eosinophilic cationic protein (ECP) as a biological indicator of disease activity in patients with eosinophilic pneumonia (EP). ECP levels were measured in serum and bronchoalveolar lavage fluid (BALF) samples from patients with EP or other diffuse interstitial lung diseases and from healthy subjects. Also we performed immunohistochemical staining of lung tissue sections from patients with EP using anti-EG 2 antibody, and computed the correlation between the number of EG 2-positive cells in lung tissues and ECP levels in serum and BALF from patients with EP. Levels of ECP in serum and BALF samples from patients with EP were significantly elevated compared to the levels in samples from other interstitial lung-disease patients and healthy subjects. Additionally, changes in serum ECP levels reflected the clinical courses for EP patients. Approximately 90 percent of the infiltrated eosinophils in tissue sections from patients with EP were EG 2-positive and activated. The number of EG 2-positive cells in lung tissues correlated significantly with levels of ECP in serum and BALF samples from patients with EP. These findings suggested that ECP levels in serum and BALF reflect the degree of eosinophil activation in lung tissues and the degree of disease activity in patients with EP. We concluded that ECP may serve as a useful biological indicator in EP.     

Effects of 60 Hz electromagnetic fields on early growth in three plant species and a replication of previous results

OBJECTIVE: To examine the relation between obstetric factors and the prevalence of urinary incontinence three months after delivery. DESIGN: 2134 postal questionnaires sent between August 1989 and June 1991. SETTING: Teaching hospital in Dunedin, New Zealand. SUBJECTS: All women three months postpartum who were resident in the Dunedin area. MAIN OUTCOME MEASURE: Prevalence of urinary incontinence. RESULTS: 1505 questionnaires were returned (70.5% response rate). At three months postpartum 34.3% of women admitted to some degree of urinary incontinence with 3.3% having daily or more frequent leakage. There was a significant reduction in the prevalence of incontinence for women having a caesarean section, in particular in primiparous women with a history of no previous incontinence (prevalence of incontinence following a vaginal delivery 24.5%, following a caesarean section 5.2% P = 0.002). There was little difference between elective caesarean sections and those carried out in the first and second stages of labour. The odds ratios for women having a caesarean section were 0.4 (95% confidence interval (CI) 0.2.-0.7) (all women and all primiparae) and 0.2 (95% CI 0.0-0.6) (primipara with no previous incontinence) in comparison with those having a normal vaginal delivery. The prevalence of incontinence was also significantly lower in women having had two caesarean sections (23.3%; P = 0.05) but similar in those women having three or more caesarean sections (38.9%) in comparison with those women who delivered vaginally (37.7%). Other significant independent odds rations were found for daily antenatal pelvic floor exercises (PFE) (0.6, 95% CI 0.4-0.9), parity > or = 5 (2.2, 95% CI 1.0-4.9) and pre-pregnancy body mass index (1.07, 95% CI 1.04-1.10). CONCLUSIONS: Adverse risk factors for urinary incontinence at three months postpartum are vaginal delivery, obesity and multiparity (> or = 5). Caesarean section and daily antenatal PFE appear to be protective, although not completely so.     

Repeatability of cellular and soluble markers of inflammation in induced sputum from patients with asthma

Sputum induced by inhalation of nebulized hypertonic saline is increasingly used to monitor airways inflammation in asthma. The aim of this study was to assess the repeatability of measuring cellular and soluble markers of inflammation in whole sputum samples as obtained by sputum induction in patients both with mild and moderate-to-severe asthma. Twelve patients with mild, atopic asthma without inhaled steroid treatment and nine patients with moderate-to-severe, atopic asthma treated with inhaled steroids were studied on two separate days at least 2 days apart. Whole sputum samples, induced by inhalation of hypertonic (4.5%) saline, were homogenized, and analysed for differential cell counts and for concentrations of albumin, fibrinogen, interleukin-8 (IL-8), and eosinophil cationic protein (ECP). Repeatability was expressed as intraclass correlation coefficient (Ri), and as coefficient of repeatability (CR) in percentage cells or in doubling concentration. Samples from two patients with mild asthma contained more than 80% squamous cells and were excluded from analysis. The repeatability for cell differential counts in both groups combined was: for neutrophils, Ri = 0.57 and CR = 31.0; for eosinophils, Ri = 0.85 and CR = 12.4; and for lymphocytes, Ri = 0.76 and CR = 6.9. The repeatability of the fluid phase measurements was: for albumin, Ri = 0.71 and CR = 3.2; for fibrinogen, Ri = 0.88 and CR = 2.8; for IL-8, Ri = 0.66 and CR = 2.2; and for ECP, Ri = 0.82 and CR = 1.1. We conclude that the repeatability of cellular and soluble markers of inflammation in induced sputum from patients with mild and moderate-to-severe asthma is satisfactory. Hence, induced sputum, processed by using the whole expectorated sample, seems to be a valuable method to monitor airway inflammation in asthma.     

Eosinophil markers in seasonal allergic rhinitis. Intranasal fluticasone propionate inhibits local and systemic increases during the pollen season

BACKGROUND: The purpose was to study activation markers of the eosinophil granulocytes in seasonal allergic rhinitis, and the impact of topical steroid therapy thereupon. METHODS: Sixty-three rhinitis patients with monoallergy to grass were examined before and at peak pollen season. Blood eosinophil count, eosinophil cationic protein (ECP), and eosinophil peroxidase (EPO) in serum and nasal lavage fluid were measured. During the season, patients were randomized to treatment with intranasal fluticasone propionate 0.1 mg o.d. (n=26), 0.2 mg o.d. (n=25), or placebo (n=12). Six healthy persons served as controls. RESULTS: During the season, all parameters, except nasal lavage ECP, increased in the placebo group (P<0.001-P<0.05). Significant differences were seen between the steroid groups and the placebo group for all parameters (P<0.001-P<0.05). Higher eosinophil count (P<0.05), serum EPO (P<0.02), and nasal lavage EPO (P<0.05) were found in patients before season than in controls. The following winter, 44 patients returned for repeated measurement. Lower levels of nasal lavage EPO were observed for patients than levels at the beginning of the season (P<0.0001). CONCLUSIONS: Intranasal fluticasone propionate reduced inflammation of the nasal mucosa, demonstrated locally by nasal lavage ECP and EPO, and systemically by blood eosinophils, serum ECP, and serum EPO. EPO seemed more sensitive than ECP as indicator of allergic inflammation. EPO demonstrated some perennial eosinophil activity in hay fever patients, increasing locally during spring.     

Activated immune system in patients with Huntington''s disease

Abnormalities of immune system compartments were determined in 12 patients with Huntington's disease (eight males, four females; age 42.4+/-11.7 years) and 11 controls (7 males, 4 females; age 47.0+/-12.0). All patients were free from infectious diseases. Serum concentrations of a panel of serum soluble markers of immune activation were investigated, namely neopterin, 55-kDa-type soluble tumor necrosis factor receptor (sTNF-R), interleukin-2-receptor (sIL-2R), kynurenine, tryptophan, immunoglobulins (Ig) A, M and G as well as routine laboratory tests. Compared to controls, we found significantly higher serum levels of IgA (p<0.01), sTNF-R, sIL-2R, neopterin, and complement component C3 (all p<0.05), and serum tryptophan was decreased (p<0.001). Higher concentrations of circulating immune complexes, cardiolipin antibodies, IgM, neopterin and lower tryptophan were associated with loss of cognitive function as assessed by the mini-mental-test. Five patients died within 1 year after measurements were performed. In these patients IgM, circulating immune complexes and neopterin concentrations were higher compared to survivors and serum tryptophan was lower. The data indicate an activation of various immune system compartments in Huntington's disease and that systemic immunological alterations might be important in the course of the disease.     

Soluble interleukin-2 receptor and urinary neopterin concentrations in malignant lymphoma

The serum concentrations of soluble interleukin-2 receptors and urine neopterin were studied in 82 patients with malignant lymphomas (25 patients with Hodgkin's disease and 57 patients with non-Hodgkin's lymphoma. Increases in soluble interleukin-2 receptors and in urinary neopterin were significantly correlated with the clinical phase of the disease. The average values in both Hodgkin's disease and non-Hodgkin's lymphoma patients suffering from the disease in its active phase were significantly higher than those of patients in complete remission. Neopterin concentrations (but not soluble interleukin-2 receptor concentrations) were also elevated in clinical stages III-IV of each disease. Urinary neopterin correlated directly and significantly with the erythrocyte sedimentation rate and inversely with haemoglobin. Finally, a longitudinal analysis showed a general tendency for the markers to return to normal values, in accordance with the favourable outcome of therapy; this was more evident for urinary neopterin than for soluble interleukin-2 receptors. These findings seem to confirm that soluble interleukin-2 receptors and especially urinary neopterin can be useful markers for monitoring and prognosis of malignant lymphomas.     

Antigen-releasing polymer rings and microspheres stimulate mucosal immunity in the vagina

Several recent studies suggest that direct application of antigen to the vaginal surface may enhance local IgA secretion, but the most effective methods for stimulating immunity at the vaginal surface have not been identified. We used antigen-loaded, biocompatible, vaginal rings to provide controlled and sustained antigen delivery directly to the vaginal mucosal surface. Mice were primed with ferritin, either subcutaneously or orally by ferritin-loaded polymer microspheres, and vaginally boosted by insertion of a ferritin-loaded polymer ring. We found that the vaginal rings were a convenient method for providing controlled antigen delivery to the vagina. Subcutaneously primed mice receiving ferritin-loaded vaginal rings had ferritin-specific IgA in their mucus secretions, while mice receiving blank rings did not. Oral priming with ferritin-loaded poly(lactic acid) microspheres also produced significant levels of ferritin-specific IgA in the vaginal secretions, but required the presence of cholera toxin. Controlled ferritin delivery to mucosal surfaces, either by oral, biodegradable microspheres or vaginal rings, provides a convenient and reliable method for enhancing vaginal IgA production in mice.     

The alpha-isoform of glycogen synthase kinase-3 from rabbit skeletal muscle is inactivated by p70 S6 kinase or MAP kinase-activated protein kinase-1 in vitro

OBJECTIVES: A major component of the increasing trend in cesarean sections in Western Australia is the rise in emergency cesarean sections in primiparous women. The aim of this study was to identify independent risk factors (particularly those known early in pregnancy) associated with operative delivery in low-risk primiparous women. METHODS: Retrospective multivariate logistic regression analyses of antenatal and perinatal data were conducted for all low-risk primiparous women entering labor spontaneously and giving birth in Western Australia in 1987 (n = 3641). RESULTS: Of the subjects, 58% had a spontaneous vaginal delivery, 8% had an emergency cesarean section, and 34% had an operative vaginal delivery. The significant independent risk factors for emergency cesarean section were older maternal age, shorter maternal height, heavier infant birthweight, and long labor. The risk factors for operative vaginal delivery were older maternal age, shorter maternal height, heavier infant birthweight, epidural anesthesia, labor/delivery complications, male infant, private patient status, and being married. CONCLUSIONS: This multivariate analysis confirms known risk factors for operative delivery in low-risk primiparous women and suggests that it may be possible to predict the likelihood of operative delivery for an individual woman by using knowledge of maternal age and height and assessment of infant birthweight.     

Faulty washers and soiled micropipettors may generate false positive serological results

BACKGROUND: Serological markers such as HBsAg and anti-HIV may be present in serum at very high concentrations and this may give rise to erroneous diagnoses due to cross-contamination. OBJECTIVES: To investigate poor equipment maintenance and use, including contamination with human serum, as a potential source of erroneous assay results. STUDY DESIGN: The potential of microtitre plate washers and micropipettors to transfer material between microplate wells and between specimens was examined. For the study of micropipettors we recruited 19 UK diagnostic laboratories. RESULTS: Four out of seven plate washers in use, until adjusted, had the potential to cause false positive HBsAg reactions. The centering of the probes that delivered the wash fluid, delivery pressure, wash volume and the use of a pre-programmed card to direct the washing procedure were important variables. We investigated soiling of tip cones of micropipettors. In every laboratory human IgG could be detected in at least a third of eluates from micropipettor tip cones; only 31 (14%) of 222 showed no evidence of contamination with human serum. Only one laboratory submitted eluates devoid of specific antibodies. Anti-HAV was the marker most commonly found (n = 68), followed by HBsAg (n = 27) and anti-HIV (n = 20). Seven micropipettor eluates from two laboratories were radioactively contaminated. CONCLUSIONS: Recommended precautions are regular checking, cleaning and servicing of equipment, care in interpreting weak reactions, reference back to serum left on the clot of the original specimen and testing of a follow up specimen. Poorly maintained immunoassay equipment can readily generate false positive results due to low-level cross-contamination, particularly with the current highly sensitive HBsAg and anti-HIV assays.     

Gene mapping from a bovine 1;29 DNA library prepared with chromosome microdissection

The relative concentrations of IgM and IgG antibodies (Ab) to Schistosoma mansoni soluble egg antigen (SEA) were evaluated in paired samples of venous blood sera and buffer-eluates of capillary blood drops dried on filter papers. The samples were obtained from school children at early and chronic stages of schistosomiasis diagnosed on the basis of history, clinical symptomatology and parasitological criteria. Enzyme-linked immunosorbent assay (ELISA), simultaneously performed, revealed paired samples to display comparable Ab levels in all cases. Samples from children with early schistosomiasis had specific IgM:IgG ratios greater than 1 [optical densities (O.D.) in sera and blood eluates of 0.77 +/- 0.32 and 0.68 +/- 0.30, respectively for IgM and 0.52 +/- 0.25 and 0.50 +/- 0.25 for IgG]. This ratio, however, was less than 1 in samples from chronically infected children (O.D. of 0.20 +/- 0.11 and 0.20 +/- 0.11 for IgM and 0.69 +/- 0.33 and 0.73 +/- 0.32 for IgG). The specific advantages of this simplified technique are the use of anti-SEA Abs in fingerstick blood eluates, rather than sera of venous blood to serologically diagnose schistosomiasis and to differentiate early from chronic infections particularly when used for mass screening, such as epidemiologic surveys.