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PubMed1981

Clinical and laboratory diagnosis of respiratory syncytial virus infection.

Infection with RSV is one of the most common respiratory viral infections in childhood, particularly in infants under 1 year of age. The disease is characterized by epidemic proportions of infection which occur regularly in all parts of the world in the winter months. The spectrum of the clinical disease is quite variable, and the infection may present as bronchiolitis, pneumonia, croup, or exacerbation of pre-existing reactive airway disease. Recent evidence has suggested that RSV infection may be frequently associated with apnea in infancy and possibly sudden-infant-death syndrome. Although the laboratory diagnosis of this infection can be successfully accomplished by any well-known and conventional procedures, such as tissue culture infectivity and determination of serologic response, recently it has become possible to diagnose the infection very rapidly by application of such techiques as immunofluorescent staining and enzyme-linked immunonoabsorbent assay (ELISA).

Adolescent↗
PubMed1978

Laboratory diagnosis of Rocky Mountain spotted fever by immunofluorescent demonstration of Rickettsia in Cutaneous lesions.

Direct immunofluorescent staining for Rickettsia rickettsii was performed on cryostat sections of skin biopsies from 27 patients suspected of having Rocky Mountain spotted fever. In nine of the 17 patients whose final diagnosis was Rocky Mountain spotted fever, coccobacillary forms of R. rickettsii were identified in endothelium and vascular walls within the dermis. Facotrs recognized as contributing to false-negative results were prior treatment with tetracycline or chloramphenicol for 24--48 hours or longer and failure to obtain a section through the focus of vasculitis. No false-positive result was obtained in the ten patients whose final diagnoses were not Rocky Mountain spotted fever. The laboratory test offers an immediate, positive laboratory diagnosis for this treatable, life-threatening disease.

Adolescent↗
PubMed1998

Antibody-based spot test for NADH-cytochrome b5 reductase activity for the laboratory diagnosis of congenital methemoglobinemia.

NADH (reduced Coenzyme I)-cytochrome b5 reductase (b5R) is a multifunctional redox enzyme, whose deficiency causes recessive congenital methemoglobinemia. A novel procedure for the detection of b5R activity in human hemolysates was developed, in which b5R monoclonal antibodies dot-blotted on nitrocellulose membrane was used to capture and enrich b5R from hemolysates, and the captured b5R activity was subsequently visualized with the substrate 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide. Application of this simple method to the detection of b5R activity in the hemolysates from different subjects demonstrated that it was both sensitive and reliable. Our method would be useful for the laboratory diagnosis of congenital methemoglobinemia.

Adult↗
PubMed1999

Laboratory diagnosis of herpes zoster.

Virological diagnosis of zoster should be rapid when effective antiviral chemotherapy is being considered. In the present study, vesicle specimens of 100 patients with zoster were analysed by detecting viral DNA using polymerase chain reaction (PCR). The findings were compared with those obtained by traditional virological and serological methods. PCR results confirmed the clinical diagnosis of zoster in 95%. Primers selected from varicella-zoster virus (VZV) gene 28 proved to be most sensitive. The sensitivity of virus culture was 20% (specificity 100%), of direct immunofluorescent VZV-specific antigen staining in vesicle samples 82% (specificity 76%), and in 48% there was a serological response to specific IgM and IgA antibodies within 4 days after the onset of rash. These findings suggest that PCR is the method of choice for rapid laboratory diagnosis of zoster.

Adolescent↗
PubMed1986

[Clinical significance, epidemiology and laboratory diagnosis of Campylobacter pyloridis].

In 1983, bacteriological examinations of gastric epithelium isolated a new species of bacteria, the so-called Campylobacter pyloridis. These bacteria were found in 50% of the gastroscopic examinations from patients with dyseptic disorders. C. pyloridis is a gram-negative curved bacterium. Up to now it has been found on the surface of the human gastric epithelium. C. pyloridis is rarely isolated from the healthy gastric epithelium. The gastric epithelium containing C. pyloridis mostly suffers from inflammatory infiltration or from pathological changes like chronic gastritis of type B. The route of infection is unknown. C. pyloridis has not yet been isolated outside of the human stomach. For laboratory diagnosis of a disease caused by C. pyloridis, the bacterium has to be isolated from gastric bioptic specimen. Another possibility is to check for high serum antibody levels against C. pyloridis. Direct microscopic examinations of gastric epithelium are also possible. The positive urease test is the main criterion to differentiate C. pyloridis from other human pathogenic campylobacter species. As therapeutic agents are recommended: bismuthates, amoxicillin, furazolidone and tinidazole. These agents are able to eliminate C. pyloridis from gastric epithelium and to fade away the gastritis.

Amoxicillin↗
PubMed2005

Comparison of specimen processing and nucleic acid extraction by the swab extraction tube system versus the MagNA Pure LC system for laboratory diagnosis of herpes simplex virus infections by LightCycler PCR.

A total of 563 specimens (234 dermal and 329 genital swabs) from patients suspected of having herpes simplex virus (HSV) infections were processed using two different extraction methods (the MagNA Pure LC system and the swab extraction tube system [SETS]); HSV DNA was amplified by LightCycler PCR. HSV DNA was detected in 157 of 563 specimens (27.9%) processed by the MagNA Pure LC system and in 179 of 563 specimens (31.8%) processed by SETS (P < 0.0001). There was no specimen processed by the MagNA Pure LC extraction method that was positive only for HSV DNA. Of 157 specimens positive by both methods, HSV DNA copy levels were higher (using cycle crossover points [cycle threshold {C(T)}]) with SETS (mean C(T), 25.9 cycles) than with the MagNA Pure LC system (mean C(T), 32.0 cycles) (P < 0.0001). The time to process 32 samples was longer with the MagNA Pure LC extraction system (90 min) than with SETS (35 min). HSV DNA extraction using SETS is faster, less expensive, and more sensitive than the MagNA Pure LC system and could replace the latter for the laboratory diagnosis of HSV infections using LightCycler PCR.

Clinical Laboratory Techniques↗
PubMed1982

Falsely negative laboratory diagnosis for myocardial infarction owing to the concurrent presence of macro creatine kinase and macro lactate dehydrogenase.

Macro creatine kinase (CK, EC 2.7.3.2) and macro lactate dehydrogenase (LD, EC 1.1.1.27) were both present in the serum of a 70-year-old woman with myocardial infarction. This interfered with the interpretation of the CK and LD isoenzyme analyses. Gel filtration and immunoprecipitation showed that the macro CK consisted of IgG and CK and the macro LD of IgG and LD. The IgG in this patient bound both MB and BB isoenzymes of CK, resulting in a macro CK complex that co-migrated with CK-MM on cellulose acetate electrophoresis. This situation led to a falsely negative laboratory diagnosis for myocardial infarction.

Aged↗
PubMed1979

Laboratory diagnosis of HB CC-alpha-thalassemia.

Routine laboratory investigations of hemoglobinopathies include Hb electrophoresis for abnormal hemoglobins, determination of Hb A2 (alpha 2 delta 2) for beta-thalassemia traits, staining for Hb H (beta 4) inclusions for alpha-thalassemia traits and estimation of Hb F (alpha 2 lambda 2) for the presence of hereditary persistence of fetal hemoglobin genes (HPFH). Frequently, analytical column chromatography and alpha/beta hemoglobin chain synthesis are used in the studies of more complicated hemoglobinopathies. This communication outlines the procedures used in this laboratory for the diagnosis of a case of Hb CC-alpha-thalassemia.

Adult↗
PubMedDate not supplied

[Non-viral infectious keratitis: predisposing factors, etiologic agents and laboratory diagnosis].

Infectious keratitis cause significant morbidity and, if it is not promptly and appropriately treated, can lead to severe ocular disability. Almost all cases of keratitis are associated to predisposing conditions. In occident, the main risk factor is contact lens wear, but previous ocular surgery or trauma are also important, as well as various ocular surface diseases. An enormous diversity of etiologic agents for infectious keratitis exist, including virus, bacteria, mycobacteria, fungi and parasites. This review provides literature and personal based information about main predisposing factors, etiologic agents and pathophysiology of infectious keratitis, excluding those of viral origin. Focus is made on microbiologic procedures, describing stains and media that should be used, and highlighting their utility. A special mention on particular situations is made, including laboratory diagnosis of Acanthamoeba keratitis, utility of lens cases analysis, keratitis in patients with previous treatment, as well as molecular biology techniques described in ophthalmology.

Acanthamoeba Keratitis↗
PubMed1989

Clinical and laboratory diagnosis of acrodermatitis enteropathica.

Acrodermatitis enteropathica is an inborn error of metabolism resulting in zinc malabsorption and severe zinc deficiency. From personal experience and a literature review the following conclusions were drawn: 1. Symptoms other than dermatitis, vary with age. Diarrhoea, mood changes, anorexia, and neurological disturbance were reported most frequently in infancy. Growth retardation, alopecia, weight loss and recurrent infections were prevalent in toddlers and schoolchildren. Spontaneous remission may occur at adolescence. 2. The severity of symptoms also varies. Intermittent or mild cases of the disease and those presenting with uncommon features such as ophthalmic, cerebral or hepatic involvement, are easily overlooked. In the severe cases this may result in a fatal outcome. If untreated, the overall mortality rate is 20%, being higher in males. 3. The laboratory diagnosis is hazardous. In patients, mean zinc values in serum, urine and hair were ca. 50% of normal levels. There is a 15% overlap with healthy controls; moreover, low zinc levels in serum, urine or hair are also found in other diseases. A more specific test is required. 4. In cases of doubt, in vitro or in vivo zinc absorption tests using radioisotopes (65Zn or 69mZn) may be performed. These appear not to be influenced by other conditions and show less overlap with controls. If such tests are unavailable, the clinical response to 3-30 mumol zinc/kg per day for 5 days may be awaited. This is recommended in infants or children with one or more symptoms of acrodermatitis enteropathica.

Acrodermatitis↗
PubMed1996

[Laboratory diagnosis of lupus anticoagulant].

Lupus anticoagulant (LA) prolongs clotting times in vitro, but in vivo leads to an increased risk of thromboembolic complications. LA is detected in many patients with lupus erythematosus but also in subjects without any autoimmune disease (primary antiphospholipid syndrome). We determined LA in 133 patients, mostly with lupus erythematosus and other autoimmune diseases. Three screening and two confirmatory tests based on different mechanisms of clotting system activation were used. LA was found in 34 patients. DRVVT was the most useful test in detecting LA while kaolin clotting time was the least sensitive. Anticardiolipin antibodies (ACL) of IgG class were found in 41 patients studied (31%). They were most often detected in patient positive for LA (64%). ACL IgM were not associated with prolonged clotting times. Laboratory diagnosis of antiphospholipid syndrome is easy when the presence of LA is confirmed by two independent tests and in addition ACL would be detected. In other cases, when only single tests are positive, it is suggested to repeat diagnostic procedure at least once.

Adolescent↗
PubMed2006

Evaluation of new commercial enzyme-linked immunosorbent assay kits in the laboratory diagnosis of antiphospholipid syndrome in view of the revised classification criteria of the antiphospholipid syndrome.

Amendments to the Sapporo criteria for the diagnosis of the antiphospholipid syndrome (APS) have recently be published and include testing for the presence of IgG and IgM beta2-glycoprotein I (beta(2)GPI) antibodies. The Asserachrom Antiphospholipid antibodies line (Diagnostica Stago) with a monoclonal based standardisation, was evaluated in a Lupus anticoagulant (LAC) positive (n = 138) and a LAC negative (n = 134) populations. The ELISA line consists of the Asserachrom APA Screen, the Asserachrom APA IgG,M and the Asserachrom anti-beta(2)GPI IgG and IgM. Anti-prothrombin antibodies (APT), not being included in the updated laboratory criteria, have been tested by the Asserachrom anti-prothrombin IgG,M. Imprecision characteristics showed coefficients of variation (CV) ranging from 4.9% to 13.9%. Cut-off values were calculated with the 99 percentile. The Asserachrom APA Screen showed 1,5% false positive and 0,7% false negative results in correlation with the Asserachrom APA IgG,M. 14.7% of the patients were positive for beta2GPI antibodies, 30,0% of them showed a negative Asserachrom APA Screen. beta(2)GPI antibodies may be the only test positive in a minority of patients, so the Asserachrom APA Screen and the Asserachrom anti-beta(2)GPI IgG and IgM should be performed in parallel when APS is suspected. LAC and APA assays, however, remain essential in the laboratory diagnosis of APS.

Antibodies, Anticardiolipin↗
PubMed1993

Detection of cholera toxin gene in stool specimens by polymerase chain reaction: comparison with bead enzyme-linked immunosorbent assay and culture method for laboratory diagnosis of cholera.

Stool specimens obtained from 123 hospitalized patients with acute secretory diarrhea admitted to the Infectious Diseases Hospital, Calcutta, India, were examined for isolation of Vibrio cholerae O1 by direct or enrichment plating on selective media for cholera toxin (CT) by bead enzyme-linked immunosorbent assay (bead-ELISA) and for the CT gene by polymerase chain reaction (PCR). V. cholerae O1 was isolated either by direct culture or by enrichment culture from 70 stool specimens, all of which gave positive results by PCR. Eleven specimens which were culture negative and bead-ELISA positive also gave positive results by PCR. In addition, 13 more specimens which were negative by both the culture method and bead-ELISA, were positive by PCR. With the combined results of both the culture method and the CT bead-ELISA, a confirmed laboratory diagnosis of cholera could be made from 81 stool specimens, while the combined results of the three methods, including PCR, yielded a positive result for 94 specimens examined. From these data, we conclude that PCR provides a more sensitive and specific assay for rapid diagnosis of cholera than currently available methods.

Adult↗
PubMed1982

Laboratory diagnosis of acute myocardial infarct: usefulness of determination of lactate dehydrogenase (LDH)-1 level and of ratio of LDH-1 to total LDH.

Recent development of an antibody to the M subunit of lactic dehydrogenase (LDH) allows the rapid isolation and measurement of LDH-1 levels. I and my colleagues studied 101 consecutive patients admitted to the hospital for possible acute myocardial infarct (AMI). The LDH-1 level was 100 IU/L or more, and the ratio of LDH-1 to total LDH (LDH-1/LDH-T ratio) was 0.40 or higher, during the course of illness in 93% of the patients with AMI. The specificity was 95% and the positive predictive value, 86%. These two criteria were met eight to 24 hours after the appearance of symptoms, and often persisted seven to 14 days. Measurement of LDH-1 level and LDH-1/LDH-T ratio is a useful adjunct in the laboratory diagnosis of AMI.

Adult↗
PubMed2000

Hepatitis delta virus: the molecular basis of laboratory diagnosis.

Infection with hepatitis delta virus (HDV), a satellite virus of hepatitis B virus (HBV), is associated with severe and sometimes fulminant hepatitis. The traditional methods for the diagnosis of HDV infection, such as detection of serum anti-HD antibodies, are sufficient for the clinical diagnosis of delta infection. However, such techniques lack the sensitivity and specificity required to more accurately characterize the nature of HDV infection and to assess the efficacy of therapies. Recent improvements in molecular techniques, such as HDV RNA hybridization and RT-PCR, have provided increased diagnostic precision and a more thorough understanding of the natural course of HDV infection. These advances have enhanced the clinician's ability to accurately evaluate the stage of HDV infection, response to therapy, and occurrence of reinfection after orthotopic liver transplant. This review focuses on the recent advances in the understanding of the molecular biology of HDV and in the laboratory diagnosis of HDV infection.

Hepatitis Antibodies↗
PubMed1999

Laboratory diagnosis of Pneumocystis carinii infections by PCR directed to genes encoding for mitochondrial 5S and 28S ribosomal RNA.

PCR with 5S mitochondrial ribosomal RNA (5S) target is a sensitive and specific assay for the detection of Pneumocystis carinii in clinical specimens from the respiratory tract. We developed an oligonucleotide probe directed to a 200 bp amplicon generated by fungal-specific universal primers that anneals with sequences specific for P. carinii in the 28S ribosomal RNA gene (28S). Of 50 archived bronchoalveolar lavage 1(BAL) specimens, 46 of 50 samples (92% agreement) gave the same result (23 positive, 23 negative) by PCR directed to the 5S and 28S assays. Results of calcofluor white staining of BAL smears on slides indicated agreement with the molecular results in 43 of 46 (93.5%) assays. PCR detection of P. carinii by amplification of 28S ribosomal gene target by fungal-specific primers and an organism-specific probe provides an alternate genomic target for the laboratory diagnosis of this organism.

Aged↗