Diagnosis of avian adenovirus infections using DNA in situ hybridization

Three DNA oligonucleotide probes designated FN-23, FN-48, and FN-96 were evaluated for the diagnosis of aviadenovirus infections by DNA in situ hybridization. Paraffin-embedded tissues were obtained from birds with confirmed adenovirus infection, birds with putative adenovirus infections, and birds with intranuclear inclusions caused by herpesvirus and polyomavirus. In birds with confirmed adenovirus infection, probes FN-23 and FN-96 identified 78% and 72% of diseased individuals, respectively. Only probe FN-48 detected chickens with group II adenovirus infection. In birds with putative adenovirus infection, the DNA probes confirmed aviadenovirus infections in 76% of the population. Probes FN-23, FN-96, and FN-48 detected 85%, 74%, and 18% of adenovirus-infected birds, respectively. None of the DNA probes cross-hybridized with tissues from polyomavirus-infected psittaciform birds or with tissues from a chicken with infectious laryngotracheitis. In contrast, probe FN-23 did cross-hybridize to herpesvirus-infected tissues from two of eight psittaciform birds with Pacheco's parrot disease. Probes FN-48 and FN-96 did not react with these tissues.     

Male infertility and mycoplasma infections (author's transl)

The frequency and pathogenic role of mycoplasmas in cases of male infertility were studied in 2 groups: in 69 subjects in whom the reduced fertility (most often called asthenozoospermia) could not be explained, 35 (50%) carried mycoplasmas. 120 other subjects suffering from subacute or persisting urethritis presented sperm anomalies the degree of which seemed to be proportional to the duration of the urethritis. The presence of mycoplasmas was demonstrated in 2 cases of repeated abortion. The disappearance of this microorganism after treatment resulted in satisfactory pregnancies in these cases. This work confirms the probable role of mycoplasmas in male infertility and their certain role in certain cases of repeated abortion.     

Diagnosis of Mycobacterium microti infections among humans by using novel genetic markers

As a result of DNA typing of Mycobacterium microti isolates from animals in the United Kingdom and The Netherlands, we diagnosed four human M. microti infections. These are the first M. microti infections among humans to be reported. Three of the patients were immunocompromised and suffered from generalized forms of tuberculosis. The fourth patient was a 34-year-old immunocompetent male with a persistent cough and undefined X-ray abnormalities. Two of the M. microti infections were recognized by their IS6110 restriction fragment length polymorphism (RFLP) patterns, which showed a high degree of similarity with those of M. microti strains isolated from a pig and a ferret in The Netherlands. The two other human M. microti infections were recognized by using the recently developed DNA fingerprinting method, "spoligotyping," directly on clinical material. All M. microti isolates from the United Kingdom and The Netherlands were found to contain an exceptionally short genomic direct repeat region, resulting in identical two-spacer sequence reactions in spoligotyping. In contrast, the highly similar IS6110 RFLP patterns of the vole strains from the United Kingdom differed considerably from the RFLPs of all M. microti strains isolated in The Netherlands, suggesting that geographic isolation led to divergent strains in the United Kingdom and on the continent.     

Diagnosis of mycotic infections in oncology patients using the polymerase chain reaction]

Diagnosis of mycotic infections is despite the immense effort devoted to this problem still very inaccurate. A new and promising method is the polymerase chain reaction, PCR, which theoretically can detect a single cell. In their original study the authors decided to develop a new method for the detection of fungi by PCR and to compare this examination with post-mortem findings. Thus it was possible to determine sufficiently reliably the sensitivity and specificity of the method. For the detection of fungi the authors selected the sequence coding for a small subunit of ribosomal RNA (18S rDNA). The method is able to detect the amount of DNA from some 10-100 cells. The sensitivity was 90% and the specificity 92%. The method is so far too laborious for common practice, its simplification would be however very useful.     

Catecholamine detection using enzymatic amplification

Different amplification sensors based on the substrate recycling principle were investigated with respect to their applicability to catecholamine detection. In the bioelectrocatalytic approach, glassy carbon electrodes were modified by laccase or a PQQ-dependent glucose dehydrogenase. Substrate recycling occurs and the detection limit is in the lower nanomolar concentration range (e.g. 10 nM dopamine and 1 nM noradrenaline for the laccase- and glucose dehydrogenase-modified electrodes, respectively). Combinations of glucose dehydrogenase with laccase or tyrosinase were investigated as bienzymatic probes. Among the systems we studied, the laccase/glucose dehydrogenase sensor is the most sensitive (detection limit: 0.5 nM adrenaline). The selectivities of the different sensor systems are discussed. Application of the laccase/glucose dehydrogenase electrode in different media (i.e. brain homogenate, heart effluate) was successfully shown. For samples with high concentrations of interfering substances (uric and ascorbic acid), the interferences can be effectively removed using enzymatic methods.     

Diagnosis of infections caused by atypical mycobacteria

Laboratory methods used for the differentiation of acid resistant rods of the genera Mycobacterium make use of their biological properties, in particular the growth rate on cultivation media, pigment formation, sensitivity for biochemical substances incl. antibiotics, biochemical activity and different relations to animal hosts. By testing these properties it was possible to classify mycobacteria into groups or identify different species in more detail.     

Diagnosis and management of common tinea infections

The estimated lifetime risk of acquiring a dermatophyte infection is between 10 and 20 percent. Recognition and appropriate treatment of these infections reduces both morbidity and discomfort and lessens the possibility of transmission. Dermatophyte infections are classified according to the affected body site, such as tinea capitis (scalp), tinea barbae (beard area), tinea corporis (skin other than bearded area, scalp, groin, hands or feet), tinea cruris (groin, perineum and perineal areas), tinea pedis (feet), tinea manuum (hands) and tinea unguium (nails). To determine the best treatment approach, the physician must consider several factors: (1) the anatomic locations of the infection, (2) the safety, efficacy and cost of treatment options and (3) the likelihood that the patient will comply with treatment. Newer medications in both oral and topical forms, including imidazoles and allylamines, have greatly increased the cure rate for tinea infections. Certain types of tinea may be treated with "pulse" regimens; these innovative therapies lower treatment costs and improve patient compliance.     

Diagnosis of urinary tract infections in puerperium

Urinary tract infections (UTI) are the most frequent nosocomial infections of women during puerperium. Since, in these women, diagnostic accuracy is affected by lochial secretion, suprapubic urinary bladder puncture (SPB) is recommended. Between December 1989 and January 1993, we subjected 903 women to suprapubic urinary bladder puncture (SpBP) at the 4th or 5th day after delivery. A urine culture of SpBP was done in all cases. Semiquantitative leukocyte counts (n = 891) and nitrite test (n = 830) were done on mid-stream urine (MSU). Side by side with microbiological investigation for urinary tract pathogens via SpPB, MSU was performed in 246 cases immediately after SpPB had been carried out. Leukocyte counts were also estimated in SpBP urine samples. In 370 (41.1%) of 903 SpBP, one or more microorganisms were cultivated. Only 36 (4.0%) of 903 women showed UTI symptoms. Microorganisms were detectable via SpBP in only 26 (72.7%) of these 36 symptomatic patients. Vaginal-operative or secondary caesarean section are related to an increased UTI rate (p < 0.001). UTI were also significantly (p < 0.0001) more frequent in women subjected to catheterisation sub partu (54.5%) compared to no catheterism (24.4%). No significant differences between the number of leukocytes in MSU sediment and the SpBP findings were seen. Semiquantitative leukocyte counts in SpBP offered a significantly (p < 0.001) increased number of leukocytes in cases with microorganism detection in SpBP irrespective of MSU findings. These results justify the designation of uterine tract infection also in the absence of complaints as "infection" and not common "bacteriuria".(ABSTRACT TRUNCATED AT 250 WORDS)     

Diagnosis of bronchopulmonary infections by quantification of microflora

The quantification of bacteria and fungi in sputum or bronchoaspirate is of clinical value for the diagnosis of respiratory tract infections. We have developed an easy method to count the micro-organisms in patients with respiratory tract infections. This consists of the quantification of micro-organisms by subsequent streakings of a calibrated loop on agar. The correlation between microbiological quantitative data and the clinical status of patients with lower respiratory tract infections is discussed. The data seem to indicate that certain bacteria present in sputum or bronchoaspirate above a certain concentration may be responsible for lower respiratory tract infections. In patients with immunological disorders or chronic pathologies even lower concentrations of micro-organisms in bronchial secretions probably are enough to cause infections. The advantage of this counting method of the microbic species from the respiratory tract consists of their quantification: thus we can attribute an etiological role to a high concentration of the germs, while micro-organisms at low concentrations are probably contaminants. By this method isolated colonies are obtained after 12-18 hours. The bacterial quantification, by respiratory samples examination of the same patient in the following days, allows us to evaluate the efficacy of antibacterial therapy, producing a reduction of bacterial concentration.     

Assessing auditory distance perception using perceptually directed action

Three experiments investigated auditory distance perception under natural listening conditions in a large open field. Targets varied in egocentric distance from 3 to 16 m. By presenting visual targets at these same locations on other trials, we were able to compare visual and auditory distance perception under similar circumstances. In some experimental conditions, observers made verbal reports of target distance. In others, observers viewed or listened to the target and then, without further perceptual information about the target, attempted to face the target, walk directly to it, or walk along a two-segment indirect path to it. The primary results were these. First, the verbal and walking responses were largely concordant, with the walking responses exhibiting less between-observer variability. Second, different motoric responses provided consistent estimates of the perceived target locations and, therefore, of the initially perceived distances. Third, under circumstances for which visual targets were perceived more or less correctly in distance using the more precise walking response, auditory targets were generally perceived with considerable systematic error. In particular, the perceived locations of the auditory targets varied only about half as much in distance as did the physical targets; in addition, there was a tendency to underestimate target distance, except for the closest targets.     

Diagnosis of pulmonary infections in mechanically ventilated patients

The optimal management strategy for ventilator-dependent patients who develop symptoms suggestive of lung infection remains controversial. Proponents of the empirical approach prefer to treat most patients with fever and pulmonary infiltrates with one or more new antibiotics, even if it may be difficult (1) to determine whether pneumonia has developed in such patients, (2) in case of infection, to precisely identify the responsible microorganisms and thereby select the optimal antimicrobial treatment, and (3) to avoid resorting to broad-spectrum drug coverage in patients without true infection. Our personal bias is that using bronchoscopic techniques to obtain protected specimen brush and bronchoalveolar lavage specimens from the affected area in the lung permits to devise a therapeutic strategy superior to the one based only on clinical evaluation. These bronchoscopic techniques, when they are performed before new antibiotics are administered, enable physicians to identify most patients who need immediate treatment and select optimal therapy, in a manner that is safe and well tolerated by patients. Furthermore, they frequently permit the clinician to withhold antimicrobial treatment in patients without infection, minimizing the risk of the emergence of resistant microorganisms in the intensive care unit. In patients with clinical evidence of severe sepsis, the initiation of antibiotic therapy should not, however, be delayed while awaiting bronchoscopy, and patients should be given immediate treatment with antibiotics. In that case, "simplified" non-bronchoscopic diagnostic procedures might allow obtaining reliable distal pulmonary secretions for quantitative cultures on a 24-hour basis just before the initiation of a new antimicrobial therapy.     

Measurement of anti-enzyme antibodies using an active-site directed radiolabel

A new technique is described for measuring antibodies to an enzyme which is not available in pure form. The secretions of the rat parasitic nematode, Nippostrongylus brasiliensis, were treated with tritiated diisopropylfluorophosphate. Only one component, an acetylcholinesterase, was radiolabelled. Antibodies to this enzyme in rat antisera were estimated by the Farr technique using the labelled enzyme as antigen. The acetylcholinesterase secreted by Necator americanus, the human hookworm, was similarly specifically labelled.     

Rapid diagnosis of tuberculosis using the amplification method

BACKGROUND: Amplification methods identify Microbacterium tuberculosis on the basis of genus- or species-specific sequence of bases in nucleic acids which they replete exponentially. The objective of the work was comparison of results of biological samples by the method Gen-Probe Mycobacterium tuberculosis Direct Test (MTD) using amplification of ribosomal RNA and BK by microscopy and cultivation, assessment of standard indicators of their efficiency of the method and analysis of diverging results. METHODS AND RESULTS: During the period between April 19, 1994 and October 19, 1995 a total of 650 specimens from 316 patients examined for suspected tuberculosis were processed. After decontamination the specimens were divided into two portions and examined by the Gen-Probe MTD and by classical BK microscopy and cultivation. 95 specimens were Gen-Probe MTD positive. As compared with BK cultivation the sensitivity of Gen-Probe MTD is 94.7%, the specificity 93.1%, the positive predictive value 56.8% and the negative predictive value 99.5%. Falsely positive were the specimens from 33 patients, most frequently with a diagnosis of tumours, non-specific bronchopneumonias and interstitial pulmonary fibroses. CONCLUSIONS: Gen-Probe MTD is a rapid examination with an equal or higher sensitivity than BK cultivation. The disadvantage is a somewhat lower specificity and higher cost.     

Optical amplification of ligand-receptor binding using liquid crystals

Liquid crystals (LCs) were used to amplify and transduce receptor-mediated binding of proteins at surfaces into optical outputs. Spontaneously organized surfaces were designed so that protein molecules, upon binding to ligands hosted on these surfaces, triggered changes in the orientations of 1- to 20-micrometer-thick films of supported LCs, thus corresponding to a reorientation of approximately 10(5) to 10(6) mesogens per protein. Binding-induced changes in the intensity of light transmitted through the LC were easily seen with the naked eye and could be further amplified by using surfaces designed so that protein-ligand recognition causes twisted nematic LCs to untwist. This approach to the detection of ligand-receptor binding does not require labeling of the analyte, does not require the use of electroanalytical apparatus, provides a spatial resolution of micrometers, and is sufficiently simple that it may find use in biochemical assays and imaging of spatially resolved chemical libraries.     

Diagnosis of infections caused by varicella zoster virus]

Pendred's syndrome is manifested by congenital sensorineural deafness in association with familial goiter due to defective organic binding of iodine in the thyroid gland. The majority of patients with Pendred's syndrome are euthyroid. We report on an unusual case of a patient with Pendred's syndrome presenting with amenorrhea and late-onset hypothyroidism.     

Diagnosis and management of urinary tract infections in childhood

The children at greatest risk for kidney damage are infants and young children with febrile urinary tract infection in whom effective treatment is delayed, those with gross vesico-urethral reflux, and those with anatomic or neurogenic urinary tract obstruction. Evaluation and management of pediatric patients with urinary tract infections are summarized.