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Vaccines and diagnostic methods for bovine mastitis: fact and fiction.

A number of problems are uniquely associated with vaccination of dairy cows for mastitis. One of these is that the number of mastitis pathogens is numerous and heterogeneous. Vaccine efforts have concentrated mainly on the major mastitis pathogens. While at least one S. aureus bacterin has been commercially available for a number of years, no large-scale, independent field trials have been published in refereed journals which support the efficacy of this vaccine. Experimental vaccines for S. aureus composed of pseudocapsule-enriched bacterins supplemented with alpha- and/or beta-toxoids appear promising, but none of these has been commercialized. With S. uberis, some protection against homologous strain challenges was reported recently with a live strain and a bacterin, but other data from the same laboratory showed this vaccine would not protect against heterologous challenge strains. At this time there is only one highly effective vaccine for mastitis, the core-antigen vaccine for coliform mastitis. All of the commercially available vaccines for this indication are bacterins of rough mutants of E. coli strain J5 or Salmonella spp. Preliminary success with an experimental vaccine based on the plasminogen activator of S. uberis is a very different approach for a mastitis vaccine. Little success has been reported with vaccination against other mastitis pathogens. For diagnostic methods, the high somatic cell count, as measured by direct count or indirect assays, remains the cornerstone of mastitis diagnosis. However, for subclinical mastitis, bacterial cell culture is a reliable diagnostic method. Pathogen identification may rely on older biochemical testing methods or newer commercial identification systems, depending on the laboratory budget. ELISA assays also have been used to assess herd infection status. Epidemiologic studies have used DNA fingerprinting and ribotyping, but none of these methods has yet produced an easily utilized commercial format. Within the next decade, additional efficacious vaccines for several of the most common agents for bovine mastitis are likely. A review written at that time then can be more fact than fiction.

Animals↗

Comparison of selected diagnostic methods for identification of Cryptosporidium parvum and Cryptosporidium andersoni in routine examination of faeces.

This study involved the comparison of suitability of different methods for routine diagnostics of Cryptosporidium spp. Two staining methods, one concentration-sedimentation method, seven concentration-floatation methods and one combined floatation-sedimentation method were compared. The methods were tested with two concentrations (1 x 10(5) and 1 x 10(6)/g) of C. parvum and C. andersoni. The methods were evaluated using light microscope, magnification 400x for concentration methods and 1000x for stained samples respectively. Specificity of both staining methods was 95-100%. Ziehl-Neelsen with P < 0.01 is more suitable for identification of C. andersoni and modified Milácek-Vítovec with P < 0.01 for identification of C. parvum. Concerning specificity and sensitivity, the floatation-concentration method by Sheather was found to provide the best results of all selected methods. The merthiolate iodine formaldehyde concentration (MIFC) method was the least specific one. The least suitable method concerning sensitivity and costs was the floatation method with caesium chloride (CsCl) with a specificity of 29%.

Animals↗

The value of immunoscintigraphy for the operative retreatment of colorectal cancer. Limitations of a new diagnostic method.

In 42 patients with suspected recurrent colorectal cancer, results of conventional diagnostic methods were compared with those of immunoscintigraphy. In 69% of all cases, the intraoperative findings of a second-look operation served for validation, whereas in 31% close follow-up was used. Recurrent tumors were successfully localized in 83% of patients by conventional methods, whereas immunoscintigraphy was expressive in 57% of cases. Immunoscintigraphy was disappointing especially because of its low sensitivity (23%) and low predictive value (positive, 33%; negative, 37%) with regard to successful diagnosis of extrahepatic tumors compared with the results of conventional methods (77% sensitivity; positive, 94%; negative, 79%). The rate of false-positive results was relatively high with immunoscintigraphy (n = 12), 83% of which were related to extrahepatic recurrent tumors. The value of immunoscintigraphy using an immunococktail of 131-J-labeled F(ab')2 fragments of monoclonal antibodies against CEA, with Ca 19-9 as an additional diagnostic tool for early detection of recurrent colorectal cancer, must therefore be viewed critically.

Antibodies, Monoclonal↗

A rapid diagnostic method for a retrotransposal insertional mutation into the FCMD gene in Japanese patients with Fukuyama congenital muscular dystrophy.

Fukuyama-type congenital muscular dystrophy (FCMD) is characterized by congenital muscular dystrophy in combination with central nervous system (CNS) abnormalities. Differential diagnosis of FCMD from Duchenne and Becker muscular dystrophies (DMD/BMD) or other types of congenital muscular dystrophy is occasionally difficult, because of their phenotypic similarity. The gene (FCMD) responsible for FCMD at 9q31 was isolated in 1998. In Japan, most FCMD-bearing chromosomes (87%) have a 3-kb retrotransposal insertion into the 3'-untranslated region (UTR) of the gene that could be derived from a single ancestral founder. Nine non-founder mutations have been identified in Japanese FCMD patients. Severe phenotype was significantly more frequent in patients who were compound heterozygotes for a point mutation and the founder mutation, than in homozygotes for the founder mutation. We developed a PCR-based diagnostic method for a rapid detection of the retrotransposal insertion mutation. Using this system, we screened 18 FCMD patients, and found 16 homozygotes and two heterozygotes for the insertion. We also evaluated the carrier frequency in the normal Japanese population. Six of 676 persons were recognized as a heterozygous carrier. Furthermore, we found three homozygotes for the FCMD founder mutation among 97 patients who had been said to have probable DMD/BMD without any DMD mutations. On the other hand, there were no FCMD homozygotes but four heterozygous carriers among 335 patients with DMD mutations. The diagnostic method we developed will provide a rapid and reliable diagnosis of FCMD, which can bring important information in genetic counseling, such as the accurate mode of inheritance, recurrence risk and a life expectancy.

Genetic Counseling↗

Comparison of diagnostic methods for detecting gastric Helicobacter-like organisms in dogs and cats.

Diagnostic methods for detecting gastric Helicobacter-like organisms (GHLOs) in dogs and cats were compared. Samples for brush cytology, the urease test and histological examination were collected post mortem from the fundus, corpus and antrum of 10 dogs (17 sample sites from each animal) and 10 cats (14 sample sites each). Samples of tissue from the fundus or corpus were taken for transmission electron microscopy and culture from three and eight dogs, respectively, and from six cats that gave a positive urease test with samples from these regions. In all dogs and in six of the 10 cats, GHLOs were detected by at least one of three methods (brush cytology, urease test or histological examination) in all regions. By brush cytology, GHLOs were demonstrated in all samples from the dogs and the positive cats. In cats, the urease test (60 min) gave a positive result in every sample site; in dogs it gave a positive result in 100% of the corpus samples, in 95% of the fundus samples and in 62% of the antral samples. Histological examination revealed GHLOs in all samples from the fundus and corpus of the dogs and of the positive cats; and in 74% and 91.7% of the antral samples of the dogs and cats, respectively. GHLOs were seen in all dogs and cats studied by transmission electron microscopy, and culture of gastric tissue was successful in 3/8 dogs and 1/6 cats. In this study, brush cytology was thus the most sensitive method for demonstrating GHLOs.

Animals↗

[Comparative analysis of 2 diagnostic methods of human loiasis: IgG4 serology and nested PCR].

By evaluating the diagnostic methods developed in our laboratory, the prevalence of loaiosis was estimated among 201 individuals from the province of Haut Ogooué in Gabon using IgG4 serology and nested-PCR. The study showed that the prevalence of loaiosis was higher than that described using standard microscopy. IgG4-based ELISA (Enzyme Linked Immunosorbant Assay) using crude extract of Loa loa microfilariae showed that 80% (35/44) of microfilaraemic individuals (MF') and 56% (88/157) of amicrofilaraemics (AMF) presented antibodies. By contrast, L. loa specific DNA amplified by nested-PCR was detected in all MF and in 68% (106/157) of AMF. Among the 201 samples tested, 95 (47%) gave positive results in both tests. These results indicate that the presence of IgG4 antibodies directed against crude extract of L. loa microfilariae is not linked to the positivity of nested-PCR assay (chi 2 for paired data = 8.78; P < 0.02). We conclude that the PCR assay is more sensitive than the detection of IgG4 antibodies (directed against crude extract of L. loa microfilariae) in detecting loaiosis, and particularly occult loaiosis (infection without circulating microfilariae).

Animals↗

[Evaluation of 3 diagnostic methods in premature rupture of membranes: diamine-oxidase assay, alpha-fetoprotein assay, colorimetric method evaluating the pH].

The authors set out to assess the three diagnostic methods available which can detect early breaking of the membranes: radio-enzymatic assay of diamine-oxidase (DAO), radioenzymatic assay of alpha-fetoprotein (AFP), colorimetric method for determining pH (Amnicator). Between June 1991 and March 1992, 114 samples of vaginal secretions were taken from 104 pregnant patients being followed up at Maternity Unit A, Bordeaux (France). The results of the assays were expressed in quantitative terms (microU/ml for DAO and ng/ml for AFP); ROC (Receiver Operating Characteristic) curves were used to determine the positivity threshold in terms of the sensitivity and specificity (20 microU/ml for DAO and 15 ng/ml for AFP). The sensitivity of the pH test was 97.5%, which was significantly better than that of DAO (90.2%) and even that of AFP (82.9%). However, there was no difference between the specificities of the pH, DAO and AFP tests (93.3%, 96.6% and 93.5% respectively). The data were compared with those in the literature. The problems in collecting the vaginal secretions probably accounts for the better results of the colorimetric test. This is a reliable, fast and easily reproducible test; these qualities make it the preferred test in EBM, and it can be completed using a radioenzymatic method (DAO) or immunoradiometric test (AFP).

Adult↗

Evaluation of a polymerase chain reaction diagnostic method and risk factors for cytomegalovirus pneumonia.

In order to evaluate the diagnostic methods and risk factors for cytomegalovirus (CMV) pneumonia, 22 patients with suspected CMV pneumonia were examined by means of the polymerase chain reaction (PCR) and serological (Ab) methods (complement fixation test = CF and enzyme-immunoassay = EIA: IgG, IgM). Thirteen patients showed positive for either the PCR or serological method; the PCR method was positive in 77% (10/13) (sputum = 8/10, bronchoalveolar lavage fluid = 3/4, peripheral blood = 3/12, urine = 2/11) and the serological method in 64%(7/11)(CF = 5/10, IgG = 3/11, IgM = 0/11). All patients diagnosed as having CMV pneumonia had underlying disease, most of which were idiopathic interstitial pneumonia and malignancies. Twelve out of 13 patients had been treated with steroids for long- or short (pulse)-periods. The cure rate was high for these patients whose PCR results became negative following anti-CMV treatments. These results indicate that a) the steroid treatment acts as a risk factor for the CMV pneumonia, b) the PCR method is a useful tool not only for early diagnosis but also for assessment of the therapeutic effect on CMV pneumonia, and c) concomitant assays of PCR and Ab may be preferable in making a conclusive diagnosis of CMV pneumonia.

Adult↗

[Community-acquired legionellosis in the Barcelona region between 1992 and 1999: epidemiological characteristics and diagnostic methods].

BACKGROUND: The epidemiological characteristics of community-acquired legionellosis are not well known. We present here legionellosis cases appearing in Barcelona, Spain, districts during 1992-1999. PATIENTS AND METHOD: Questionnaire on socio-demographic, epidemiological, clinical and diagnostic data. 285 community-acquired cases of legionellosis were notified (67% of total). Incidence values increased from 0.03/100,000 in 1992 to 3.14 in 1999. Mostly used diagnostic method since 1996 was the urinary antigen test. CONCLUSIONS: The incidence of legionellosis increased sharply during the studied period. We believe that use of urinary antigen-based diagnosis allows for a better knowledge of community-acquired legionellosis.

Community-Acquired Infections↗

Comparison of the diagnostic methods used in maxillofacial trauma.

A prospective study was performed to evaluate the diagnostic methods used in acute maxillofacial trauma. Clinical examination, routine facial x-rays with linear tomography, and computer tomography were compared in 49 patients. Computer tomography was found to be the most accurate test in the diagnosis of facial bone injury, especially complex fractures. Computer tomography also provided valuable information regarding soft-tissue injury of the face. The radiation doses of linear tomography and computer tomography were calculated to be below the level known to cause cataract formation. Computer tomography is a safe, reliable adjunct in the diagnosis of acute maxillofacial trauma and should be strongly considered after initial screening measures are completed.

Adolescent↗

[Complex diagnostic method of early forms of cancer of the uterine cervix].

A complex of diagnostic procedures including extended colposcopy, aiming biopsy, cytological examination and endocervical curettage was carried out in 110 patients for differential diagnosis between precancerous diseases and early forms of carcinoma of the uterine cervix. Application of the complex diagnostic method may be recommended for identification of early stages of malignancy in cervix uteri. Due to the findings obtained, it becomes possible to give a more accurate definition of pathologic process necessary for determination of therapy to be carried out in patients with cervical carcinoma in situ which has been detected without colposcopy. Cytological method appeared to provide much information on tissue specimens.

Adult↗

Characterization of allergenic food proteins for improved diagnostic methods.

PURPOSE OF REVIEW: Diagnostic decision points for food allergen-specific serum IgE concentration and for skin prick test results have been established for several foods, reducing the requirement for food challenges in a number of patients. Many patients, however, still need to undergo oral food challenges because their food-specific IgE level is in the undefined range. In addition, diagnostic decision points could not be established for several foods. It appears that measurement of serum specific IgE concentrations to individual allergens is superior to determination of specific IgE to the crude food extract containing allergenic and nonallergenic proteins. This review will outline recent advantages in characterization of food allergens as well as the relevance of this knowledge for use in recently developed protein microarray technology. RECENT FINDINGS: Protein microarrays have been developed to profile allergen-specific IgE antibodies from human serum with the advantage of screening hundreds of allergens in parallel using minute amounts of blood. This technology, however, requires prior knowledge of the proteins to be studied. The identification and characterization of clinically relevant allergens have increased dramatically within the last several years. Relevant new allergens have been identified, especially in tree nuts and seeds. Interestingly, most of these allergens belong to the same family of seed storage proteins. In addition, known food allergens have been further characterized and IgE-binding sites have been determined. Moreover, 'informative' peptides shown to be predictive for the persistence of food allergy have been identified. SUMMARY: The combination of food allergen characterization and protein or peptide microarray technology will enable us to develop improved diagnostic tools in food allergy.

Allergens↗

[Evaluation of diagnostic methods in anatomic urinary incontinence in gynecology].

The present study was undertaken with the aim of verifying the value of diagnostic methods in female stress incontinence. In their diagnostic work the authors used urethrocystography, measuring of the urethral length and resistance. Displacement of the internal urinary meatus related to the interior border of the symphysis was also observed. In demonstrable incontinence the average posterior urethrovesical angle was 140 degrees, and in the absence of incontinence 120 degrees. It was also found that the difference between the pressure of the internal urinary meatus in straining and non-straining women with incontinence was +0,7 mm Hg and in those without incontinence +4,5 mm Hg. It has been observed, furthermore, that the relation between the vertical displacement of the internal urinary meatus in rest and stress was less than 5 in women with incontinence. In women without incontinence it was more than 5. There was no difference in the range of the urethral length in women either with or without stress incontinence.

Female↗

[Advantages and limitations of diagnostic methods for H. pylori infection].

The diagnosis of H. pylori infection is based on methods requiring gastric biopsies performed during endoscopy (histology, culture, rapid urease test, PCR) or on non-invasive methods (serology, 13C urea breath test, stool antigen test). Histology is routinely performed on gastric biopsies, also allowing the description and the classification of the gastric inflammatory mucosal lesions associated with H. pylori. The rapid urease test is less sensitive but specific. It can be done by the gastroenterologist himself, mainly when a duodenal ulcer is found at endoscopy,and may be followed by histological testing in case of a negative result. The culture of biopsies may be helpful in determining in vitro patterns of antimicrobial resistance and sensitivity in planning second line treatment for a patient after eradication failure. Non-invasive methods are not appropriate for determining the underlying disease, which may be associated with H. pylori infection. Serological tests are widely available and cheap, and may be helpful-in screening populations or in confirming the presence H. pylori infection in case of equivocal results of the other diagnostic methods due to bleeding ulcers, antibiotic and/or antisecretory treatments. The 13C urea breath test is the most accurate method in patients irrespective of age. Stool antigen testing is a promising method because its diagnostic performances approach those obtained with urea breath test. This technique is easy to perform, and its accuracy may be improved by the use of monoclonal antibodies recently proposed for capturing H. pylori antigen in stool specimen. The eradication control is recommended at least 4 weeks after the end of the eradication treatment or at least 2 weeks after antisecretory treatment to obtain high sensitive results. If endoscopic control is necessary, a biopsy culture with antibiotic testing is recommended in combination with histology, because of the actual development of antibiotic resistances. Looking for H. pylori virulence markers remains a promising research topic but is not yet recommended in routine practice.

Antigens, Bacterial↗