Observations on neonatal mortality of the Chacoan peccary, Catagonus wagneri.

The considerable neonatal mortality of a captive population of Chacoan peccaries, the taguá (Catagonus wagneri), in Paraguay was investigated with the examination of six newborn animals and one adult. Most deaths occur primarily because of restriction of space resulting in competition for space and nutrition. The adult had nonlethal inhalation pulmonary anthracosis. Neonatal pulmonary nocardiosis was noted in one infant and is believed to be related to the dust storms prevailing locally. Another neonate had a duplication of the pelvis, rear extremities, and one ovary, representing a type of conjoined twin classified as ischiopagus.

Isolation and characterization of a polyol-responsive monoclonal antibody useful for gentle purification of Escherichia coli RNA polymerase.

A modified enzyme-linked immunosorbent assay (ELISA) was used to screen monoclonal antibodies (MAbs) that react with Escherichia coli RNA polymerase for the ability to release the RNA polymerase in the presence of a low molecular weight polyhydroxylated compound (polyol) and a non-chaotropic salt. This assay, termed the ELISA-elution assay, identified 19 presumptive "polyol-responsive" MAbs out of a total of 218 antigen-specific MAbs screened. One of these MAbs, designated NT73, was examined in detail for the ability to release the antigen in response to various combinations of polyol and salt. Using NT73 conjugated to Sepharose, highly active RNA polymerase could be prepared rapidly by a single immunoaffinity chromatography step, replacing two lengthy chromatographic steps in our conventional purification procedure. Because NT73 reacts with the beta' subunit of RNA polymerase, a mixture of the core polymerase and holoenzyme was recovered from the immunoaffinity column. The holoenzyme (E sigma 70) could be separated from the core polymerase by subsequent chromatography on a Mono Q column. This demonstrates that polyol-responsive MAbs can be easily identified and characterized by the ELISA-elution assay. The use of polyol-responsive MAbs provides a means of adapting immunoaffinity chromatography to the purification of labile proteins.

Thoracic radiographic features of silicosis in 19 horses.

Clinical records and thoracic radiographs of 19 horses with a confirmed pathologic diagnosis of silicosis were reviewed. These horses had histories of varying degrees of chronic weight loss, exercise intolerance, and respiratory distress. At the time of presentation, two horses were asymptomatic. Ten horses were geldings and nine were female. The mean age of the 19 horses was 10.7 +/- 5.5 years. Fourteen horses were identified as being from the Monterey-Carmel Peninsula of midcoastal California. An abnormal, structured interstitial pulmonary pattern was identified on thoracic radiographs in each horse. The interstitial pulmonary changes were classified as miliary (13 horses), reticulonodular (4), or linear interstitial (2), and were best visualized dorsally and caudodorsally. In addition to the abnormal interstitial pulmonary pattern, areas of pulmonary consolidation were evident caudodorsally in seven horses. Other thoracic radiographic features included: hilar lymphadenopathy (4 horses), pleural effusion/thickening (4), cranial mediastinal lymphadenopathy (2), hyperinflation (1), and a discrete pulmonary mass (1). Necropsy findings in eight horses and results of lung biopsies in an additional five horses showed a diffuse, multifocal, granulomatous pneumonia with areas of pulmonary fibrosis. Cellular infiltrates included predominantly macrophages with intracellular and/or extracellular crystalline material, occasional lymphocytes, and giant cells. Similar cellular changes were also identified, during necropsy, in the hilar and tracheobronchial lymph nodes in each of the eight horses, although gross enlargement of the lymph nodes was present in only six horses. The radiographic and pathologic findings of these 19 horses are consistent with chronic or the accelerated forms of silicosis that are recognized in humans.

Use of Mono Q high-resolution ion-exchange chromatography to obtain highly pure and active Escherichia coli RNA polymerase.

A method for the purification of highly pure and active Escherichia coli RNA polymerase holoenzyme is described. This method is simple, reproducible, and can be performed at room temperature. The procedure involves the high-performance liquid chromatography of a partially purified RNA polymerase sample on a Mono Q ion-exchange column. Under the conditions used, RNA polymerase holoenzyme is well separated from the core RNA polymerase and other impurities. The purified RNA polymerase contains virtually no impurities as judged by SDS-polyacrylamide gel electrophoresis. The purified RNA polymerase holoenzyme contains the sigma 70 subunit in stoichiometric amounts and is at least 90% active.

Comparison of two sample collection methods for quantitative bacteriologic culture of canine prostatic fluid.

Ejaculate, urine, urethral swab specimens, and ultrasonography-guided small-needle prostatic cyst aspiration and/or tissue core biopsy specimens were collected for bacteriologic culture from 25 dogs in which prostatic disease was suspected on the basis of history, clinical signs of disease, or results of physical examination. The prostate gland in each dog was examined ultrasonographically, and the tissue core biopsy specimens were examined histologically and bacteriologically. Two methods were used to assess bacterial prostatitis. In 5 dogs (20%), bacteriologic culture results of paired urethral swab and ejaculate specimens differed from culture results of specimens obtained by needle aspiration of prostatic cyst fluid or tissue core biopsy. The prostate gland in 17 dogs had 1 or more cystic, fluid-filled structures (0.5 to 4.0 cm in diameter). Ultrasonographic appearance of the prostate gland did not have obvious correlation with culture results from dogs of the study. Histologic results of prostatic tissue core biopsy specimens correlated well with culture results.

Sonography of the liver, gallbladder, and spleen.

Focal hepatic and splenic lesions, vascular abnormalities, and disorders of the biliary system can readily be detected with ultrasonography. The sonographic diagnosis can be substantially narrowed when the presenting clinical signs are considered. Ultrasonography is less helpful when the liver or spleen is diffusely involved without parenchymal, abnormalities. However, certain diseases may also be eliminated from diagnostic consideration on the basis of this finding. Percutaneous ultrasound guided biopsy markedly improves the success and safety of obtaining a definitive diagnosis when either diffuse or focal lesions are present. Sonography has also been very beneficial for serially evaluating the response to therapy once focal lesions of the liver or spleen have been identified.

Echocardiographic evaluation of cardiac tamponade in dogs before and after pericardiocentesis: four cases (1984-1986).

The echocardiographic (M-mode and 2-dimensional) features (before and after pericardiocentesis) of 4 dogs with pericardial effusion and clinical evidence of cardiac tamponade were reviewed. M-Mode echocardiography revealed pericardial effusion, with exaggerated swinging motion of the heart and abnormal septal motion in all 4 dogs. In each case, 2-dimensional echocardiography demonstrated right ventricular diastolic free-wall collapse. Three dogs had right atrial diastolic collapse as well. Clinical signs improved, and right ventricular and right atrial diastolic collapse subsided after pericardiocentesis. Two-dimensional echocardiographic features of right atrial and ventricular collapse were used as indicators for determining the presence of cardiac tamponade.

Gadolinium-DTPA enhancement of VX-2 carcinoma of the rabbit kidney on T1 weighted magnetic resonance images.

Experimental renal carcinoma was induced by percutaneous injection of VX-2 carcinoma cells into the left kidney in New Zealand white rabbits. Magnetic resonance imaging (MRI) was performed at 0.15 T before and after intravenous injection of 0.3 mmol gadolinium-DTPA (Gd-DTPA) per kg body weight. Gd-DTPA enhanced the tumors by increasing the signal intensity on T1 weighted images. The enhancement was evident immediately after Gd-DTPA injection, increasing during the observation time of 30 minutes. Histologically the areas of enhancement corresponded well to the viable tumor tissue.

Gadolinium-DTPA enhancement of experimental soft tissue carcinoma and hemorrhage in magnetic resonance imaging.

An experimental series in the rabbit was performed to test gadolinium-DTPA (Gd-DTPA) enhancement of VX-2 carcinoma and hemorrhages induced in the soft tissues. The recognition of both malignant and benign lesions was greatly facilitated on T1 weighted images after intravenous administration of 0.3 mmol Gd-DTPA/kg body weight because of reduced T1 relaxation times. Gd-DTPA enhancement reached its maximum after 10-15 minutes and was most apparent in tumor tissue, connective tissue surrounding the tumor and in the area of fresh hemorrhage.

Ectopic ureter in a dog: extension from the kidney to the urinary bladder and to the urethra.

An ectopic ureter extending to the urinary bladder and to the proximal portion of the urethra was diagnosed in a 6-month-old dog with urinary incontinence. The diagnosis was made by use of excretory urography. The kidney and ureter were removed. When urinary incontinence continued, positive-contrast cystography was performed. The ectopic ureter was found to bypass the bladder via a submucosal extension that emptied into the urethra.

Sonography of the liver, gallbladder, and spleen.

Focal hepatic and splenic lesions, vascular abnormalities, and disorders of the biliary system can readily be detected with ultrasonography. The sonographic appearance in certain cases may be nonspecific, but the differential diagnosis can be substantially narrowed when the presenting clinical signs are considered. Ultrasonography is less helpful when the liver or spleen is diffusely involved without parenchymal abnormalities. However, certain diseases may also be eliminated from diagnostic consideration on the basis of this finding. Percutaneous ultrasound guided biopsy markedly improves the success and safety of obtaining a definitive diagnosis when either diffuse or focal lesions are present. Sonography has also been very beneficial for serially evaluating the response to therapy once focal lesions of the liver or spleen have been identified.

Purification and characterization of wheat germ DNA topoisomerase I (nicking-closing enzyme).

Wheat germ contains an enzyme capable of removing supercoils from circular DNA. We have purified this enzyme using Polymin P fractionation, ammonium sulfate precipitation, and chromatography on Bio-Rex 70 and phenyl-Sepharose. Renaturation after electrophoresis on sodium dodecyl sulfate-polyacrylamide gels shows that topoisomerase activity is associated with a polypeptide with a Mr = about 111,000. The enzyme is similar to other eukaryotic type I DNA topoisomerases (nicking-closing enzymes) by the following criteria: it is capable of increasing or decreasing the topological linking number of covalently closed DNA substrate; it is capable of restoring an equilibrium distribution of linking numbers to DNA substrate with a single unique linking number; and it does not require magnesium ion or ATP for activity.

Purification and properties of the sigma subunit of Escherichia coli DNA-dependent RNA polymerase.

An improved purification procedure is described for the sigma subunit of escherichia coli DNA-dependent RNA polymerase [ribonucleoside triphosphate:RNA nucleotidyl-transferase, EC 2.7.7.6]. The method involves chromatography of purified RNA polymerase on single-stranded DNA-agarose, Bio-Rex 70, and finally Ultragel AcA44. The sigma factor obtained is electrophoretically pure with a yield of about 40%. A number of the chemical--physical properties of sigma are presented. A molecular weight of 82,000 was determined by phosphate buffered sodium dodecyl sulfate--polyacrylamide gel electrophoresis. Ultraviolet absorption spectra were used to determine an E280nm 1% of 8.4. The amino acid composition and 12-residue N-terminal sequence (Met-Glx-Glx-Asx-Pro-Glx-(Ser or Cys)-Glx-Leu-Lys-Leu-Leu) of sigma have been determined. The isoelectric focusing properties of sigma are presented. Denaturation--renaturation studies indicate that sigma is capable of an unusually rapid and complete recovery of activity after being subjected to denaturing conditions. A stable, 40,000-dalton fragment is generated from sigma by mild trypsin treatment.