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Biomedical subjects

S J Shin

Publications and source records attributed to S J Shin.

At least 145 records · Page 8Linked to original sources

Malignant edema in horses.

Malignant edema (clostridial myositis) was diagnosed in 9 horses with signs of illness that included fever, depression, painful muscular swellings, and toxemia. The infection followed intramuscular injections in 8 horses and developed in a puncture wound in 1 horse. Treatment consisted of surgical fenestration of the involved muscle, high doses of penicillin, nonsteroidal anti-inflammatory agents and analgesics, and supportive fluid therapy. Five horses recovered and 4 died. Those that died had advanced signs of the disease at admission.

Animals↗

Nucleotide sequence of yellow fever virus: implications for flavivirus gene expression and evolution.

The sequence of the entire RNA genome of the type flavivirus, yellow fever virus, has been obtained. Inspection of this sequence reveals a single long open reading frame of 10,233 nucleotides, which could encode a polypeptide of 3411 amino acids. The structural proteins are found within the amino-terminal 780 residues of this polyprotein; the remainder of the open reading frame consists of nonstructural viral polypeptides. This genome organization implies that mature viral proteins are produced by posttranslational cleavage of a polyprotein precursor and has implications for flavivirus RNA replication and for the evolutionary relation of this virus family to other RNA viruses.

Base Sequence↗

Variable persistence of the contagious equine metritis organism in the genital tract of CBA/J, CBA/N, LAF1/J, BALB/c and congenitally thymus-deficient (nude) mice.

Five inbred strains of mice, CBA/J, CBA/N, LAF1, BALB/c and congenitally thymus-deficient nude mice of BALB/c background, varied considerably in their susceptibility to the contagious equine metritis organism (CEMO). Whereas all the strains were virtually refractive to vaginal challenge, LAF1 and CBA/N mice were readily infected by intra-uterine inoculation. Based on infection rate and nature of the bacteriological response, CBA/N mice appeared the more susceptible of the 2 strains. Attempts to transmit CEMO to thymus-deficient nude mice were unsuccessful by both of these routes of challenge and by intraperitoneal inoculation, indicating that host resistance to the causal agent is independent of thymus-mediated immune phenomena. No clinical evidence of infection was observed in any of the experimentally infected mice. Although persistence of CEMO in the female reproductive tract varied widely, it could be isolated from some of the CBA/N mice for as long as 19 weeks after challenge by the intra-uterine route. The organism was cultured from the ovaries and/or oviducts of a high percentage of one group of CBA/N mice after 50 days, when it could no longer be recovered from the remainder of the genital tract. Limited attempts to achieve venereal transmission of CEMO between culture-positive female and companion male CBA/N mice were unsuccessful. The relative susceptibility of the CBA/N strain of mice to CEMO would suggest that host resistance to this infection is at least partly dependent on the presence of a fully functional B lymphocyte system. Further studies in this experimental model may elucidate some of the immunological mechanisms underlying development of resistance in the horse, more specifically as they relate to the occurrence of the carrier state in this disease.

Animals↗

Pharmacokinetics of a long-acting oxytetracycline preparation in ring-necked pheasants, great horned owls, and Amazon parrots.

After a single IV or IM dose of a long-acting oxytetracycline (OTC) preparation, serum concentrations were determined at various times in the ring-necked pheasant, great horned owl, and Amazon parrot. Pharmacokinetic parameters, including serum half-life (t1/2) and apparent volume of distribution (Vd) were calculated from the OTC concentration-time curves for each species and route of administration. Significant differences (P less than 0.05) were found in the t1/2 and Vd parameters between species and routes of administration. Dosage regimens to maintain minimum OTC concentration of 5 micrograms/ml of serum were calculated from the t 1/2 and Vd values obtained, using steady-state pharmacokinetics. In the pheasant, the calculated mean IV dose was 23 mg/kg of body weight every 6 hours, whereas the mean IM dose was 43 mg/kg every 24 hours. The mean IM dose was 16 mg/kg every 24 hours for the owl and 58 mg/kg every 24 hours for the parrot. The small volumes required for treatment, the long-dosing interval obtainable, and the broad spectrum of antimicrobial activity of the long-acting OTC preparation studied offered major advantages over other antibiotics commonly used in treating avian species.

Animals↗

Isolation of Actinobacillus lignieresii from enlarged tongue of a horse.

In the horse described herein, Actinobacillus lignieresii was associated with a syndrome identical to wooden tongue in cattle. It responded rapidly to systemic sodium iodide and antibiotic therapy. The definitive diagnosis was based on cytologic examination and culture. If actinobacillosis is suspected, immediate treatment with sodium iodide should be instituted along with supportive therapy.

Actinobacillosis↗

Transmissibility of the contagious equine metritis organism for the cat.

A group of SPF cats were moderately susceptible to the causal organism of contagious equine metritis (CEM) following intra-uterine or intrapreputial challenge with an Irish streptomycin resistant strain isolated from a clinically infected mare. Subclinical infections were established in only 50% of the cats, none of which became long-term carriers of the organism. Cytological examination of vaginal smears was of no diagnostic value in confirming infection in inapparently infected cats. Bacteriological responses after primary or secondary challenge with the CEM organism were essentially similar, with one exception, a female cat in which there was possible evidence of local immunity persisting after the primary infection. Efforts to reactivate shedding subsequent to the immediate post-challenge period were unsuccessful. Throughout the experimental period, the cats remained sero-negative to the complement-fixation test, and they failed to develop any significant increase in the levels of antibody activity as measured by the kinetics-based ELISA or KELA system. On day 89 after primary challenge, the cats were euthanized and various sites in the genitourinary tract and the internal iliac lymphatic glands subjected to bacteriological and pathological examination for evidence of CEM infection with negative results. The findings of this study, although establishing the transmissibility of the CEM organism for the cat, demonstrate the limited value of this species as an experimental model system for the disease in the horse.

Animals↗

Absorption and distribution patterns of oral phenoxymethyl penicillin (penicillin V) in the horse.

Serum levels of phenoxymethyl penicillin (penicillin V; Pen V) were measured following oral administration of two different formulations of the drug to five healthy horses. The mean serum concentration profile was described by a two-compartment model with a first order rate of absorption. Half-lives of the absorption, distribution and elimination phases were, respectively, 0.199 +/- 0.035, 0.362 +/- 0.060 and 3.650 +/- 0.575 hours. The distribution of the drug to body fluid compartments other than serum was examined. Mean peak levels of Pen V in serum, synovial fluid, peritoneal fluid and urine were, respectively, 2.38 +/- 0.18, 0.35 +/- 0.02, 0.25 +/- 0.06 and 472 +/- 80 micrograms/ml with times to achieve peak concentration ranging from 30-360 minutes after oral administration. Steady state pharmacokinetic measurements predicted that minimum serum Pen V concentrations of 0.1 micrograms/ml would be maintained by oral administration of the drug (110,000 I.U./kg) at 8 hour intervals. Our data indicate that oral Pen V is a feasible approach to long-term penicillin therapy in the equine patient.

Administration, Oral↗

Phenoxymethyl penicillin in the horse: an alternative to parenteral administration of penicillin.

This preliminary study evaluated phenoxymethyl penicillin (Penicillin V) as an alternative to parenteral administration of penicillin in horses. Penicillin V was administered orally to five horses at two different doses and plasma levels of the drug were determined at timed intervals. The results were evaluated by regression analysis. Following the administration of penicillin V at a dose of 66,000 IU/kg or 110,000 IU/kg, the mean peak plasma levels obtained were 1.55 micrograms/mL and 2.34 micrograms/mL respectively. A plasma level two to four times above the minimal inhibitory concentration level of Streptococcus equi and Streptococcus zooepidemicus was maintained for 325 minutes at 66,000 IU/kg and 349 minutes at 110,000 IU/kg. Penicillin V given orally was thus shown to be an acceptable alternative to parenteral administration of penicillin in the horse.

Absorption↗

Energy metabolism of the contagious equine metritis bacterium.

The energy metabolism of the English E-CMO strain of contagious equine metritis bacterium was studied in whole cells and cell extracts. This bacterium appears to have an active Krebs cycle and probably obtains energy by oxidative phosphorylation since glycolysis and the hexose monophosphate pathways appear to be absent. These conclusions are based on the findings that [U-14C]glucose incorporation by this bacterium is below the level of detection, and that respiration is stimulated by Krebs cycle intermediates (i.e., malate, citrate, and succinate), but not by glucose, fructose, maltose, or sucrose. Furthermore, support comes from the fact that enzymes generally associated with the Krebs cycle and electron transport (i.e., malate dehydrogenase, succinate dehydrogenase, isocitrate dehydrogenase, fumarate hydratase, malate dehydrogenase [decarboxylating], cytochrome oxidase, superoxide dismutase, NADH dehydrogenase, and catalase) were detected. Those enzymes normally associated with glycolysis and the hexose monophosphate pathways (i.e., hexokinase, glucose 6-phosphate dehydrogenase, fructose biphosphate aldolase, glycerol 3-phosphate dehydrogenase, phosphoenolpyruvate carboxykinase, pyruvate kinase, phosphate acetyl transferase, acetate kinase, alcohol dehydrogenase, and lactate dehydrogenase) were below the level of detection.

Animals↗

Electronic probe measurements of cervico-vaginal mucus for detection of ovulation in dairy cows: sanitation, clinical observations and microflora.

An electronic vaginal probe with a sanitizing carrier unit has been designed to measure changes in the electrical resistance of cervico-vaginal mucus in the cow. Over 400 cows and heifers have been probed during the period prior to breeding. When 33 heifers and cows were probed 2-3X per day for 30 days, mild irritation of the vaginal mucosa developed during the luteal phase. In all other studies no grossly detectable lesions or other complications resulting from probing were observed either in experimental herds or in farmer herds where breeding tests were conducted. Fertility of probed cows was equal to cows inseminated when estrus was detected visually. Weekly culture of microorganisms from cervico-vaginal mucus collected from three cows probed 3X per week for 22 days resulted in no detectable change in the population of microorganisms. The number of isolates each successive week was 11, 8, 8 and 5, respectively. The sanitary procedures followed appeared to prevent introduction of organisms of any consequence, as judged by the decreasing number of isolates during the probing sequence.

Animals↗

Bovine salmonellosis attributed to Salmonella anatum-contaminated haylage and dietary stress.

An epizootic of salmonellosis in a dairy herd started 2 days after the feeding of a new shipment of medicinal-smelling soybean meal. Clinical findings consisted of diarrhea or fever (greater than 39 C), or both, and markedly decreased milk production. The attack rate was 73% in lactating cows, 3% in calves, and 0% in nonlactating cows. There were no deaths, but 1 cow aborted a late-term fetus. Salmonella anatum was isolated from feces, milk, pharynx, uterine fluid, haylage, and bird droppings from a hayfield. The epidemiologic findings suggested that haylage contaminated by wild birds and improperly stored in a silo was the source of infection and that the precipitating event was ingestion of spoiled soybean meal.

Animal Feed↗

Canine parvovirus in a commercial kennel: epidemiologic and pathologic findings.

A study was conducted at a large canine commercial kennel that had suffered serious losses due to epidemic diarrheal disease following the introduction of canine parvovirus (CPV) into the kennel population. Mortality was highest in weaned (9- to 12-week-old) puppies coincident with the decline in maternal antibody titers. Virus was present in fecal samples from both fatal and non-fatal cases. Intestinal lesions of varying severity were present in dogs that died. One case of myocarditis occurred in a 5-week-old puppy. Reproductive performance was unaffected by the introduction of canine parvovirus into the kennel population.

Animals↗

The bacteriological culture of equine uterine contents, in-vitro sensitivity of organisms isolated and interpretation.

A total of 19 pathogenic bacterial species was isolated from uterine swabs of 498 out of 1539 mares over 4 years. The swabs were taken by 5 veterinary clinicians using 2 different techniques. Bacterial contamination during swabbing was minimized by scrupulous attention to cleansing of the external genitalia and the perineal area, and in the handling of the culture specimen. The most prevalent organisms isolated were beta-haemolytic streptococcus (39%), Escherichia coli (27%) and Klebsiella pneumoniae (7%). Interpretation of microbiological findings correlated well with clinical findings when number of organisms isolated and endometrial cytology were considered. The use of a bacterial transport medium combined with sophisticated culture methods reflects a more accurate picture of the uterine microflora than can be obtained by previous techniques. Streptococci isolated were uniformly sensitive to penicillins. The sensitivity of E. coli and K. pneumoniae towards chloramphenicol, gentamicin and polymyxin was nearly 100%. The selection of an appropriate antibacterial agent depends upon sensitivity, pharmacological action, genital tract status and cost. This study shows that a Gram stain of uterine cytology can be used to diagnose quickly and select an appropriate antibiotic for treatment prior to culture results if sufficient numbers of organisms are present.

Animals↗