Mycobacterium species identification and rifampin resistance testing with high-density DNA probe arrays.

Species identification within the genus Mycobacterium and subsequent antibiotic susceptibility testing still rely on time-consuming, culture-based methods. Despite the recent development of DNA probes, which greatly reduce assay time, there is a need for a single platform assay capable of answering the multitude of diagnostic questions associated with this genus. We describe the use of a DNA probe array based on two sequence databases: one for the species identification of mycobacteria (82 unique 16S rRNA sequences corresponding to 54 phenotypical species) and the other for detecting Mycobacterium tuberculosis rifampin resistance (rpoB alleles). Species identification or rifampin resistance was determined by hybridizing fluorescently labeled, amplified genetic material generated from bacterial colonies to the array. Seventy mycobacterial isolates from 27 different species and 15 rifampin-resistant M. tuberculosis strains were tested. A total of 26 of 27 species were correctly identified as well as all of the rpoB mutants. This parallel testing format opens new perspectives in terms of patient management for bacterial diseases by allowing a number of genetic tests to be simultaneously run.

Idiopathic dilated cardiomyopathy in Dalmatians: nine cases (1990-1995).

OBJECTIVE: To describe the historical, clinical, and echocardiographic findings in Dalmatians with dilated cardiomyopathy (DCM). DESIGN: Retrospective case series. SAMPLE POPULATION: 9 Dalmatians with a diagnosis of DCM and congestive heart failure (CHF), 9 Doberman Pinschers with DCM and CHF, and 9 dogs of other breeds with DCM and CHF. PROCEDURE: Disease history; signalment; physical, radiographic, and echocardiographic examination findings; treatment; and outcome from medical records were analyzed. RESULTS: All Dalmatians were male, with a mean age of 6.8 years. Eight dogs had been fed a commercially available low-protein diet formulated for the prevention of urate uroliths. All dogs had clinical signs consistent with left-sided CHF and had marked left ventricular systolic dysfunction and severe left ventricular dilatation, although arrhythmias were not an important finding in this series of dogs. Median duration of survival was 10 months. CLINICAL IMPLICATIONS: The DCM syndrome in Dalmatians has some qualities that are distinct from DCM in other breeds of dogs.

Recommendations for standards in transthoracic two-dimensional echocardiography in the dog and cat. Echocardiography Committee of the Specialty of Cardiology, American College of Veterinary Internal Medicine.

Recommendations are presented for standardized imaging planes and display conventions for two-dimensional echocardiography in the dog and cat. Three transducer locations ("windows") provide access to consistent imaging planes: the right parasternal location, the left caudal (apical) parasternal location, and the left cranial parasternal location. Recommendations for image display orientations are very similar to those for comparable human cardiac images, with the heart base or cranial aspect of the heart displayed to the examiner's right on the video display. From the right parasternal location, standard views include a long-axis four-chamber view and a long-axis left ventricular outflow view, and short-axis views at the levels of the left ventricular apex, papillary muscles, chordae tendineae, mitral valve, aortic valve, and pulmonary arteries. From the left caudal (apical) location, standard views include long-axis two-chamber and four-chamber views. From the left cranial parasternal location, standard views include a long-axis view of the left ventricular outflow tract and ascending aorta (with variations to image the right atrium and tricuspid valve, and the pulmonary valve and pulmonary artery), and a short-axis view of the aortic root encircled by the right heart. These images are presented by means of idealized line drawings. Adoption of these standards should facilitate consistent performance, recording, teaching, and communicating results of studies obtained by two-dimensional echocardiography.

Instrumentation, principles, and pitfalls of ultrasonography.

Diagnostic ultrasonography has had a major impact on clinical diagnosis in veterinary medicine. Improved instrumentation (increased resolution and reliability) and ease of operation resulted in acceptance of ultrasonography as a diagnostic tool in private practice. As with any new imaging modality, sources of error exist. Operator inexperience and "overdiagnosis" of the image are major sources of error in the early stages of ultrasound training. The ultrasound examination of the animal should always be evaluated in conjunction with the history, physical examination, and other laboratory findings. Errors in interpretation most often occur when the ultrasound image is evaluated without respect to this complete data base. It must be stressed that ultrasonography does not replace, but is a valuable adjunct to, plain-film radiography.

Congenital heart disease.

The clinical usefulness of M-mode and two-dimensional echocardiography has been proven over the years. M-mode echocardiography allows an 'ice-pick' sampling of the heart, but in conjunction with two-dimensional echocardiography, assessments of cardiac structure and, to some extent, myocardial function can be appreciated. The limitations of these techniques include difficulty in 1) diagnosing subtle congenital heart disease and 2) estimating the severity of valvular lesions (stenosis and regurgitation). Doppler echocardiography overcomes these limitations by detecting abnormal direction, velocity, and turbulence of the blood flow (Chapter 2). This chapter will focus mainly on the two-dimensional and M-mode echocardiographic features of common congenital heart disease.

Plasma taurine concentrations and M-mode echocardiographic measures in healthy cats and in cats with dilated cardiomyopathy.

M-mode echocardiography was completed and plasma taurine concentrations were determined in 79 healthy cats and 77 cats with dilated cardiomyopathy (DCM). In healthy cats, a relationship was not observed between plasma taurine concentrations and any M-mode echocardiographic measurement. End-systolic and end-diastolic cardiac chamber dimensions were larger; wall thickness measures were smaller; and calculations of fractional shortening were less in cats with DCM than in healthy cats. Plasma taurine concentrations less than 30 nmol/mL were detected in 7/79 healthy cats and in 52/77 cats with DCM. Of the 52 cats with DCM and an initial plasma taurine concentration less than 30 nmol/mL, 23 died or were euthanized during the first post-treatment week, 7 were lost to further study, and 22 improved after taurine supplementation. Of the 25 cats with DCM and an initial plasma taurine concentration greater than or equal to 30 nmol/mL, 9 died or were euthanatized during the first post-treatment week, and 9 were lost to further study. Two cats did not improve, of which one died and one was euthanatized 4 to 8 weeks after initiation of taurine supplementation. Five cats with a plasma taurine concentration greater than or equal to 30 nmol/mL improved after taurine supplementation. Myocardial function subsequently deteriorated in three of these cats. Two of the three cats had signs of congestive heart failure redevelop.

Transient, traumatically induced, central diabetes insipidus in a dog.

A 9-year-old mixed-breed dog was evaluated for dental malocclusion secondary to mandibular fractures that had been repaired after the dog had been hit by a car. The dog had hypernatremia, high plasma osmolality, low urine osmolality, and hyposthenuria with adequate fluid administration. Skull radiography revealed a fracture line at approximately the level of the pituitary fossa. Administration of exogenous vasopressin resulted in an increase in urine specific gravity and urine osmolality, a decrease in serum osmolality, and a normalization of serum sodium concentrations. Follow-up evaluation revealed a reduction in the frequency of exogenous treatment with vasopressin over the ensuing months, indicating transient, traumatically induced, central diabetes insipidus.

Post-traumatic stress syndrome and sexual dysfunction.

There recently has been a tremendous amount of literature concerning post-traumatic stress disorder in both the scientific and the lay literature. However, with all the interest, and all the material that has been generated, symptoms of sexual dysfunction, which may be present in a significant number of patients suffering from this disorder, have not been included in the diagnostic criteria or clinical descriptions. While working with Vietnam veterans who possessed the diagnosis of post-traumatic stress disorder during 1984 at a New York area Veteran's Administration Hospital, it became apparent that many of these men suffered from erectile difficulties. While these observations are by no means epidemiologically significant, they do suggest that the sexual status of this patient population deserves investigation.

Acute mitral regurgitation with papillary muscle rupture in a dog.

Papillary muscle rupture is uncommon in the dog. Two-dimensional echocardiography provides a rapid, noninvasive test in the diagnosis of acute, severe mitral regurgitation resulting from papillary muscle rupture. This report illustrates the usefulness of echocardiography to determine the cause of acute mitral regurgitation.

Removal of hepatitis B virus infectivity from human gamma-globulin prepared by ion-exchange chromatography.

Hepatitis B virus infectivity can be removed from human plasma used to prepare a gamma-globulin product by ion-exchange chromatography with commercially available resins. A pooled human plasma sample free of hepatitis markers was contaminated with 10,000 chimpanzee infectious doses of hepatitis B virus per milliliter from a known infectious inoculum. The contaminated plasma was diluted to yield a weakly positive radioimmunoassay result for HBsAg and then processed over a double-column chromatography system containing anionic ion-exchange resins to yield highly purified gamma-globulin. Two chimpanzees were each inoculated intravenously with this product while a control animal received non-treated material. The 2 experimental animals each received a potential challenge of 3,000 ID and showed no serologic evidence of the disease during 9 months of evaluation. The control animal received 100 ID and developed hepatitis B 25 weeks after the challenge.

Anti-HBc, HBeAg and DNApolymerase activity in healthy HBsAg carriers and patients with inflammatory liver diseases.

In this paper we report on anti-HBc-titers, HBcAg, DNApolymerase activity in the serum and intracellular HBsAg in healthy HBsAg-carriers and patients with HBsAg-positive inflammatory liver diseases. 32/44 patients with acure virus-B-hepatitis were negative for anti-HBc in the first week of the disease. Anti-HBc-titers in healthy HBsAg-carriers varied between 1:10 and 1:32,000 (medium titer 1:4,000). In HBsAg-positive CAH we found a medium titer between 1:32,000 and 1:64,000, in cases with CPH of about 1:16,000. All autoimmune type CAH showed anti-HBc-titers less than 1:10. By immunofluorescence we could demonstrate in a group of 71 asymptomatic HBsAg-carriers in none of the healthy HBsAg-carriers HBcAg in the liver cell nuclei. In contrast HBcAg could only be found in 4/5 HBsAg positive CAH- and 6/9 CPH patients. No elevated DNApolymerase activity could be demonstrated in healthy HBsAg-carriers. Out of 44 patients with virus-B-hepatitis only 3 showed elevated DNApolymerase activity. On the other hand DNApolymerase elevation was demonstrable in 17/37 cases with CAH and 9/15 with CPH. The investigations showed a strong correlation between the demonstration of HBcAg in the serum and the DNApolymerase activity. The characteristic findings enabled us to differentiate between "healthy" HBsAg-carriers and HBsAg-carriers with inflammatory liver diseases.

Type B hepatitis after needle-stick exposure: prevention with hepatitis B immune globulin. Final report of the Veterans Administration Cooperative Study.

Hepatitis B immune globulin (HBIG) and immune serum globulin (ISG) were examined in a randomized, double-blind trial to assess their relative efficacies in preventing type B hepatitis after needle-stick exposure to hepatitis B surface antigen (HBsAG)-positive donors. Clinical hepatitis developed in 1.4% of HBIG and in 5.9% of ISG recipients (P = 0.016), and seroconversion (anti-HBs) occurred in 5.6% and 20.7% of them respectively (P less than 0.001). Mild and transient side-effects were noted in 3.0% of ISG and in 3.2% of HBIG recipients. Available donor sera were examined for DNA polymerase (DNAP) and e antigen and antibody (HBeAg; anti-HBE). Both DNAP and HBeAg showed a highly statistically significant correlation with the infectivity of HBsAg-positive donors. Hepatitis B immune globulin remained significantly superior to ISG in preventing type B hepatitis even when the analysis was confined to these two high-risk subgroups. The efficacy of ISG in preventing type B hepatitis cannot be ascertained because a true placebo group was not included.

The demonstration of subtype (D or Y)-specific determinants on the surface of the presumed hepatitis B virus.

Dane particles isolated from the sera of HBsAg/ad and HBsAg/ay carriers were reacted with monospecific antibodies to the d and y subtype-specific determinants of HBsAg/. Dane particles from HBsAg/ad expressed the d determinant on their surfaces and those from HBsAg/ay sera contained the y specificity. Both complete (DNA-P and HBcAg) and defective (HBcAg alone) Dane particles expressed the subtype-specific determinants.

Expression of hepatitis B virus-specific markers in asymptomatic hepatitis B surface antigen carriers.

A study was undertaken to assess the state of hepatitis B virus infection in a group of asymptomatic hepatitis B surface antigen (HBsAg) carriers. This study confirmed that the presence of hepatitis B e antigen (HBeAg) in serum was closely associated with serum HBsAg-specific deoxyribonucleic acid polymerase activity, hepatitis B core antigen (HBcAg) in serum and liver cell nuclei, and a histological picture of chronic hepatitis. No HBsAg-specific deoxyribonucleic acid polymerase activity or HBcAg was detected in highly concentrated anti-HBe-positive sera. In addition, liver biopsy specimens from carriers with anti-HBe were negative for HbcAg by immunofluorescence, and the liver histology was either normal or revealed only fatty changes. These data indicate that the anti-HBe-positive sera contained either no Dane particles or, if present, at least a 500-fold-lower concentration of Dane particles than that found in HBeAg-positive sera.

Transmission of hepatitis B to chimpanzees by hepatitis B surface antigen-positive saliva and semen.

To assess the infectivity of hepatitis B surface antigen (HBsAg)-containing body fluids other than blood, chimpanzees were inoculated intravenously with saliva and semen obtained from HBsAg-positive individuals implicated in non-percutaneous transmission of hepatitis B. Saliva and semen samples were negative for occult blood. The titer of HBsAg in saliva was on the average only 1/3,000 that of the corresponding serum. One chimpanzee, inoculated sequentially with saliva from three individuals, developed HBsAg at 9 weeks and serum glutamic pyruvic transaminase elevation at 13 weeks after injection. HBsAg persisted for 15 weeks. This animal also developed e antigen, anti-core antibody, and anti-surface antibody. Liver biopsies showed acute hepatitis that subsequently resolved. A second chimpanzee, inoculated with HBsAg-positive semen, developed HBsAg and elevated serum glutamic pyruvic transaminase 4 weeks after inoculation and then died suddenly without explanation. HBsAg was positive in two consecutive samples and was confirmed by specific neutralization. Autopsy did not reveal evidence of hepatitis. This study demonstrates that HBsAg-positive saliva and, probably, semen contain infectious virus and suggests that saliva and/or semen may serve as important mechanisms in the transmission of type B hepatitis.