Biomedical subjects

R Dubielzig

Publications and source records attributed to R Dubielzig.

12 recordsLinked to original sources

PubMed2001

DNA helicase-mediated packaging of adeno-associated virus type 2 genomes into preformed capsids.

Helicases not only catalyse the disruption of hydrogen bonding between complementary regions of nucleic acids, but also move along nucleic acid strands in a polar fashion. Here we show that the Rep52 and Rep40 proteins of adeno-associated virus type 2 (AAV-2) are required to translocate capsid-associated, single-stranded DNA genomes into preformed empty AAV-2 capsids, and that the DNA helicase function of Rep52/40 is essential for this process. Furthermore, DNase protection experiments suggest that insertion of AAV-2 genomes proceeds from the 3' end, which correlates with the 3'-->5' processivity demonstrated for the Rep52/40 helicase. A model is proposed in which capsid-immobilized helicase complexes act as molecular motors to 'pump' single-stranded DNA across the capsid boundary.

Capsid↗

PubMed1999

Adeno-associated virus type 2 protein interactions: formation of pre-encapsidation complexes.

The nonstructural adeno-associated virus type 2 Rep proteins are known to control viral replication and thus provide the single-stranded DNA genomes required for packaging into preformed capsids. In addition, complexes between Rep proteins and capsids have previously been observed in the course of productive infections. Such complexes have been interpreted as genome-linked Rep molecules associated with the capsid upon successful DNA encapsidation. Here we demonstrate via coimmunoprecipitation, cosedimentation, and yeast two-hybrid analyses that the Rep-VP association also occurs in the absence of packageable genomes, suggesting that such complexes could be involved in the preparation of empty capsids for subsequent encapsidation steps. The Rep domain responsible for the observed Rep-VP interactions is situated within amino acids 322 to 482. In the presence of all Rep proteins, Rep52 and, to a lesser extent, Rep78 are most abundantly recovered with capsids, whereas Rep68 and Rep40 vary in association depending on their expression levels. Rep78 and Rep52 are bound to capsids to roughly the same extent as the minor capsid protein VP2. Complexes of Rep78 and Rep52 with capsids differ in their respective detergent stabilities, indicating that they result from different types of interactions. Rep-VP interaction studies suggest that Rep proteins become stably associated with the capsid during the assembly process. Rep-capsid complexes can reach even higher complexity through additional Rep-Rep interactions, which are particularly detergent labile. Coimmunoprecipitation and yeast two-hybrid data demonstrate the interaction of Rep78 with Rep68, of Rep68 with Rep52, and weak interactions of Rep40 with Rep52 and Rep78. We propose that the large complexes arising from these interactions represent intermediates in the DNA packaging pathway.

Blotting, Western↗

PubMed1998

Urinary obstruction in a hermaphroditic llama.

A 24-hour-old cria was admitted for evaluation of stranguria evident shortly after birth. On physical examination, the prepuce appeared to be normally formed and small drops of fluid dripped from it as the cria strained to urinate. Testes could not be palpated. Ultrasonographic examination revealed that the bladder was distended. The only abnormality detected on serum biochemical analysis was high creatinine concentration. Tube cystostomy was performed, and the cria was treated with saline (0.9% NaCl) solution administered intravenously and antibiotics. Four days after admission, the cria could not urinate normally when the cystostomy tube was occluded. Five days after admission, normograde cystography and retrograde urethrography were performed. Radiographic findings indicated the cria was an intersex llama with urethral duplication. The llama was euthanatized at the owner's request. Necropsy revealed bilateral ovotestes with a phenotypically female reproductive tract and urethral duplication. Urethral duplication should be considered as a cause of stranguria in male neonatal crias, and hermaphroditism should be included as a cause of urethropathies in llamas.

Animals↗

PubMed1995

Neuronal ceroid lipofuscinosis in the Polish Owczarek Nizinny (PON) dog. A retinal study.

Visual dysfunction and neurological symptoms were found in Polish Owczarek Nizinny (PON) dogs. Two dogs were examined, one at 2 years of age and the other one at 4 years. The oldest dog was totally blind. The 2-year-old dog developed mental disturbances and the 4-year-old dog became severely ataxic. Ophthalmoscopical findings were retinal hyper-reflectivity, attenuation of the retinal vessels and the presence of greyish to brown spots in the fundus. Electrophysiological and ultrastructural studies were performed in the 2-year-old dog. Scotopic ERG responses were absent, whereas 30 Hz cone flicker responses were recordable, although with an amplitude reduced to about 30% of the normal level. A slow negative potential replaced the c-wave, indicating a dysfunction of the RPE. Intracellular inclusions with a granular appearance or containing membranous fingerprint-like or curvilinear profiles, resembling ceroid, were found in different retinal cells. The RPE cells in the central areas were charged with autofluorescent material having similar structure, Photoreceptor degeneration was most severe in the central areas, corresponding to the RPE changes. It appears than the PON dog may provide a new animal model for neuronal ceroid lipofuscinosis.

Animals↗

PubMed1995

Physical examination and radiographic analysis to detect dental and mandibular bone resorption in cats: a study of 81 cases from necropsy.

The mandibles of 81 randomly selected cats were examined clinically and radiographically for dental calculus, periodontitis, odontoclastic resorptive lesions (FORL) and osteoporosis. Extent of calculus increased with increasing age. Prevalence and severity of periodontitis and FORL increased with increasing age. Osteoclastic resorption and/or osteoporosis increased with age, advancing from rostral to caudal in cortical bone. No significant correlation of periodontitis with FORL could be demonstrated.

Aging↗

PubMed1994

Effect of repeated administration of tirilazad mesylate on healthy and endotoxemic calves: a pilot study.

Tirilazad mesylate (TM:U74006F), a nonglucocorticoid 21-aminosteroid (lazaroid), is beneficial in the treatment of experimentally-induced ischemic injury following brain and spinal cord trauma, subarachnoid hemorrhage, hypovolemic shock and endotoxemia. This study investigated the effects of TM following repeated administration in sixteen healthy and endotoxemic calves. Group A calves received TM 3 mg/kg IV; group B calves received Escherichia coli endotoxin in increasing doses (0.1 to 20 micrograms/kg IV); group C calves received TM and endotoxin and group D calves received sterile saline (10 mL). Endotoxin, TM and saline were given every eight hours for five days. Mild, transient tachypnea was observed following TM administration. The drug suppressed clinical signs of endotoxemia until larger doses of endotoxin were given. At necropsy no substantial lesions were observed in groups A and D. Groups B and C had lesions consistent with endotoxemia but only group C calves had evidence of abomasal and ruminal ulceration. Although TM may be of benefit in the treatment of endotoxemia, further studies are needed to determine the optimal dosage and potential side effects in the endotoxic bovine neonate.

Abomasum↗

PubMed1993

Effect of phenylbutazone and repeated endotoxin administration on hemostasis in neonatal calves.

Twenty newborn Holstein calves were allotted at random to 4 groups: group A received 0.9% sterile saline solution; group B received phenylbutazone (5 mg/kg of body weight, IV) and 0.9% sterile saline solution; group C received progressively increasing doses of endotoxin (0.1 to 15 micrograms/kg); and group D received phenylbutazone and endotoxin similarly as did calves of groups B and C, respectively. Phenylbutazone was given once daily and saline solution or endotoxin were given every 8 hours for 5 days. Clinical variables--PCV, plasma total protein and fibrinogen concentrations, platelet count, prothrombin time, activated partial thromboplastin time, and fibrin degradation products concentration were measured at 24-hour intervals. Necropsy was performed on each calf. Phenylbutazone suppressed the clinical response to endotoxin challenge until large doses (7.5 to 15 micrograms/kg) were administered. Calves of groups C and D remained stable until they abruptly developed severe dyspnea necessitating euthanasia. Thrombocytopenia and leukopenia developed after the initial endotoxin dose. Prothrombin time was prolonged and PCV suddenly decreased at 96 hours. Necropsy revealed consistent lesions in the vascular endothelium and lungs. Phenylbutazone administration did not enhance or ameliorate endotoxin-induced hemostatic alterations or pathologic lesions.

Animals↗

PubMed1988

Processed oat hulls as potential dietary fiber sources in rats.

Processed oat hull products were evaluated as potential dietary fiber sources. Three levels, 5, 10 and 15%, of processed oat hulls, bleached oat hulls or oat hulls coated with starch, were added to purified diets and fed to groups of rats for 6 wk. Control diets consisted of 5, 10 or 15% alpha-cellulose or commercial nonpurified diet. None of the oat hull products at the three levels tested had any negative effect on rat growth. Fresh and dry fecal weights increased linearly as the concentration of dietary fiber increased and were highly correlated with fiber intake (r = 0.95). Apparent digestibility of neutral detergent fiber in all diets was low and apparent calcium absorption was not consistently affected by any diet. None of the oat hull test diets lowered plasma or hepatic cholesterol levels, a finding consistent with the failure to detect mixed-linkage beta-glucans in any of the processed oat hull products. Detailed analysis of the processed oat hull fibers also indicated that they were greater than 95% insoluble fiber and high in cellulose and xylans. Light-microscopy histology of kidney, spleen, pancreas, stomach, duodenum, ileum and colon was normal. The extent of hepatocellular destruction produced by the cholesterol (1%) and cholic acid (0.2%) added to the diet to induce hypocholesterolemia was independent of the kind and amount of dietary fiber.

Absorption↗

PubMed1987

Anterior corneal dystrophy of American Dutch belted rabbits: biomicroscopic and histopathologic findings.

Spontaneously occurring anterior corneal opacities were present in related, juvenile American Dutch belted rabbits. Slit lamp biomicroscopy revealed focal opacities of epithelium, basement membrane, and subepithelial corneal stroma. Lesions were characterized histologically by thin and disorganized surface epithelium, thickened and intensely staining epithelial basement membrane, fimbriated and irregular basement membrane-stromal juncture, and disorganized subepithelial stroma. Biomicroscopic and histopathologic features of anterior corneal dystrophy of American Dutch belted rabbits appear similar to those of human anterior corneal dystrophies.

Animals↗

PubMed1986

Malignant histiocytosis in Bernese Mountain dogs.

Malignant histiocytosis was diagnosed in 10 male and 1 female Bernese Mountain Dogs. Nine of these dogs were closely related. The disease was characterized by a rapidly progressive and inevitably fatal course. Clinical signs varied, but lethargy, anorexia, weight loss, and respiratory and CNS abnormalities predominated. The lungs were the primary site of tumor involvement in 10 dogs. The eleventh dog had lymphadenopathy and severe anemia. Metastatic lesions were detected in all dogs. Anaplastic pulmonary carcinoma was diagnosed originally in 6 of the 11 cases, but this diagnosis was changed to malignant histiocytosis after electron microscopic examination of tissues and immunohistochemical identification of histiocytic markers in the tumor cells.

Animals↗

PubMed1977

Portal vein anomaly and hepatic encephalopathy in a horse.

Periodic episodes of diffuse central nervous system disease occurred in a yearling Thoroughbred gelding that had a history of frequent respiratory tract disease and stunted growth. Hepatic encephalopathy was diagnosed on the basis of history, clinical signs, prolonged bromsulphalein clearance, and increased blood ammonia content. Because of the poor prognosis and recurrent clinical signs the horse was euthanatized. Necropsy revealed an arteriovenous anomaly and thrombosis of the portal vein. Histologically, there was diffuse primary astrocytosis of the brain.

Animals↗

PubMedDate not supplied

Postoperative myositis in a neonatal foal: a case report.

A foal with azotemia, acidemia, and electrolyte abnormalities was diagnosed with uroperitoneum. The foal was anesthetized with isoflurane, and throughout the 4 hours of anesthesia and abdominal surgery, its mean arterial pressure ranged between 45 and 65 mm Hg. The foal developed a myopathy postoperatively and died 24 hours after surgery.

Animals↗