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Biomedical subjects

J J O'Brien

Publications and source records attributed to J J O'Brien.

At least 37 records · Page 2Linked to original sources
PubMed1989

Transmission of tuberculosis from experimentally infected cattle to in-contact calves.

Five of a group of six calves were inoculated with Mycobacterium bovis. Two more uninoculated calves were introduced to the group 84 days later. All the inoculated calves were subsequently shown to be excreting M bovis in nasal mucus. The uninoculated calf in the initial group of six became infected and subsequently excreted M bovis. The two uninoculated calves which were introduced later did not become infected. It was concluded that contact with nasal mucus from the infected cattle resulted in infection of the uninoculated calf and that the density of accommodation of animals excreting M bovis was an important factor in transmission of the disease.

Animals↗
PubMed1989

Acyclovir. An updated review of its antiviral activity, pharmacokinetic properties and therapeutic efficacy.

Acyclovir (aciclovir) is a nucleoside antiviral drug with antiviral activity in vitro against members of the herpes group of DNA viruses. As an established treatment of herpes simplex infection, intravenous, oral and to a lesser extent topical formulations of acyclovir provide significant therapeutic benefit in genital herpes simplex and recurrent orofacial herpes simplex. The effect of acyclovir therapy is maximised by early initiation of treatment, especially in non-primary infection which tends to have a less protracted course than the primary episode. Long term prophylactic oral acyclovir, in patients with frequent episodes of genital herpes simplex, totally suppresses recurrences in the majority of subjects; as with other infections responding to acyclovir, viral latency is not eradicated and pretreatment frequencies of recurrence return after discontinuation of treatment. Caution should accompany the prophylactic use of acyclovir in the general population, due to the theoretical risk of the emergence of viral strains resistant to acyclovir and other agents whose mechanism of action is dependent on viral thymidine kinase. Intravenous acyclovir is the treatment of choice in biopsy-proven herpes simplex encephalitis in adults, and has also been successful in the treatment of disseminated herpes simplex in pregnancy and herpes neonatorium. Intravenous and oral acyclovir protect against dissemination and progression of varicella zoster virus infection, but do not protect against post-herpetic neuralgia. In immunocompromised patients, intravenous, oral and topical acyclovir shorten the clinical course of herpes simplex infections while prophylaxis with oral or intravenous dosage forms suppresses reactivation of infection during the period of drug administration. Ophthalmic application of 3% acyclovir ointment rapidly heals herpetic dendritic corneal ulcers and superficial herpetic keratitis. Thus, despite an inability to eradicate latent virus, acyclovir administered in therapeutic or prophylactic fashion is now the standard antiviral therapy in several manifestations of herpes simplex virus infection, and indeed represents a major advance in this regard. With the exception of varicella zoster virus infections, early optimism concerning the use of the drug in diseases due to other herpes viruses has generally not been supported in clinical investigations.

Acyclovir↗
PubMed1989

Dezocine. A preliminary review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy.

Dezocine is an analgesic agent with opioid agonist and antagonist activity. After parenteral administration of therapeutic doses it is approximately equipotent with morphine, and has proved at least as effective an analgesic as morphine, pethidine (meperidine) and butorphanol in moderate to severe postoperative pain. However, preliminary pharmacodynamic data indicate that the ceiling of analgesic activity of dezocine occurs at a higher level of analgesia than that of reference agonist/antagonist agents. Also, the drug exhibited a morphine-like degree of anaesthetic-sparing activity in animals. Although long term data are very limited, single doses of dezocine are well tolerated, with mild and transient sedation and gastrointestinal upset the principal adverse effects. As with some other agonist/antagonist analgesics, a 'ceiling' effect to dezocine-induced respiratory depression occurs with increasing dosage, beyond which further depression has not been observed. In single analgesic doses, however, dezocine is a slightly more potent respiratory depressant than morphine. Clinically important haemodynamic changes have not been observed with usual analgesic doses of dezocine. As an agonist/antagonist opioid, the dependence liability of dezocine would be expected to be lower than that of pure agonist opioids, but extended clinical use is required before more definitive conclusions can be drawn in this regard. Unlike older drugs of its type, dezocine produced opiate-like subjective effects and was identified as morphine-like by drug abusers. Thus, provided the promising conclusions of currently available clinical studies are confirmed with its wider use, dezocine should be a useful additional agent for the treatment of moderate to severe postoperative pain.

Analgesics↗
PubMed1989

Use of PPD and phosphatide antigens in an ELISA to detect the serological response in experimental bovine tuberculosis.

Five calves from tuberculosis free herds were each inoculated intranasally with 10(6) viable organisms of a field isolate of Mycobacterium bovis. Four of the calves developed acute tuberculosis. ELISAs employing protein and phosphatide extracts of M bovis as antigens were used to monitor the humoral response of the infected calves. Fourteen days after infection there was a dramatic increase in the level of antibodies demonstrated by the phosphatide antigen. This increase coincided with the first appearance of signs of the disease. The results suggest that the phosphatide antigen may be of potential value in detecting a humoral response, if present, in cattle infected with M bovis. The tests employing the protein antigen demonstrated a humoral response in only one of the infected calves and emphasises the importance of antigen selection to detect antibodies in tuberculous animals.

Animals↗
PubMed1988

Excretion of Mycobacterium bovis by experimentally infected cattle.

Three groups, each of five calves, four to seven months old, were inoculated intranasally with different numbers of Mycobacterium bovis. Infection was established readily in the calves which received an inoculum containing either 10(6) or 10(4) colony forming units (cfu). After every infection there was a lag period during which the organisms could not be isolated from specimens of nasal mucus. All the animals excreted M bovis and the time of commencement, quantity and duration of excretion appeared to be related to the inoculation dose. Excretion continued for many weeks, and for two calves excretion became intermittent over many months. All the calves which were given inocula of 92 cfu failed to develop the disease and no immunological responses were detected; however, M bovis was isolated from nasal secretions from one of these animals 100 days after inoculation.

Animals↗
PubMed1988

Mycobacterium bovis in the anterior respiratory tracts in the heads of tuberculin-reacting cattle.

Twenty-five of 50 randomly selected tuberculin-reacting cattle were confirmed as tuberculous in the laboratory. All 25 cattle had macroscopic lesions in lymph nodes associated with the respiratory tracts but only one had lung lesions. M bovis was isolated from the anterior respiratory tracts in the heads of four of the 25 tuberculous animals and from a nostril lesion found in a fifth. For at least three of these five animals, the intervals between the final tuberculin test and their previously negative tests indicated that infection had established relatively rapidly. Four of them had been tuberculin tested solely because they were animals in contiguous 'at risk' herds. It would appear that although M bovis can be isolated from the anterior respiratory tracts in the heads of tuberculin-reacting cattle, it is unlikely that primary foci of infection exist in regions other than the lungs or associated tissues. The study demonstrates the potential for reactors with lesions to excrete M bovis and the continued importance of infected cattle in the epidemiology and eradication of the disease.

Animals↗
PubMed1987

Changes in fitness and shipboard task performance following circuit weight training programs featuring continuous or interval running.

Pre- and post-physiological data were collected on 57 Navy men (mean age = 19.5 years) who participated in either circuit weight training/continuous run (CWT/CR) (N = 31) or circuit weight training/interval run (CWT/IR) (N = 26) programs. Measured variables included 4 measures of upper torso dynamic strength (one repetition maximum [1 RM] for arm curl, bench press, shoulder press, and lat pull-down); two measures of lower torso dynamic strength (1 RM) for knee extension and leg press); one measure of power (number of revolutions completed on an arm ergometer (Monark) at maximum drag); three measures of muscular endurance (number of repetitions at 60% 1 RM for bench press and leg press and maximal number of bent-knee sit-ups in 120 s); one stamina measure (time to exhaustion on a cycle ergometer (Monark) maximal work capacity [MWC] test; and three simulated shipboard tasks: manikin shoulder drag, open/secure a water tight door and paint bucket carry. Composite shipboard performance derived from the summed time (s) required to complete the three tasks was also calculated. Results show performance on the manikin shoulder drag and majority of evaluative fitness measures was significantly (p less than 0.05) enhanced following both circuit weight training/run formats. Significantly (p less than 0.05) higher values for shoulder press (F = 7.2), arm ergometer (F = 5.3), and sit-ups (F = 6.8) and lower values for leg press muscular endurance (F = 5.1) were observed in CWT/IR when compared to CWT/CR.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Bovine leptospirosis: experimental serovar hardjo infection.

Almost the full range of clinical signs observed in pregnant cattle naturally infected with Leptospira interrogans serovar hardjo was observed in this experimental study in which 22 heifers were infected by intraplacentome inoculation with serovar hardjo strains. These features included abortion, mummification, stillbirth, premature and term birth of weak calves and full-term birth of live apparently healthy calves. Leptospires were demonstrated in all but three calves by culture and or immunofluorescence.

Animals↗
PubMed1986

Bilateral "simultaneous" femoral neck fractures following minimal stress.

Following jogging, a 53-year-old man experienced bilateral hip discomfort. Two weeks later, after stepping backward suddenly, he had severe pain in the right hip. Radiographs showed a displaced fracture of the right femoral head; this was pinned. Bone imaging revealed intense uptake in the other femoral head as well. This also was believed to be fractured, and therefore was repaired. During the two operations, no pathological cause of the bilateral femoral neck fractures was noted. The literature on simultaneous bilateral femoral neck fractures, without underlying bone disease, was reviewed.

Athletic Injuries↗
PubMed1985

Bovine leptospirosis: some clinical features of serovar hardjo infection.

During an investigation of natural in utero infection of cattle by Leptospira interrogans strains, infection (almost entirely caused by serovar hardjo) was diagnosed in 57 per cent of 505 calves (472 aborted fetuses, 20 stillborn calves and 13 perinatal deaths) examined over a six-year period. The prevalence of leptospire-infected fetuses showed a seasonal increase in September, October and December and was significantly higher in fetuses aborted by dairy cows than in fetuses aborted by beef cows. The majority of infected fetuses were aborted from the sixth month of gestation onwards. Cows which aborted infected fetuses had not previously exhibited overt signs of agalactia. There was an association between leptospiral infection and retention of fetal membranes.

Abortion, Veterinary↗
PubMed1985

Fitness changes of Naval women following aerobic based programs featuring calisthenic or circuit weight training exercises.

Two research investigations were undertaken to determine the effects of experimental aerobic/circuit weight training (A/CWT) and standard Navy aerobic/calisthenic (A/CAL) training on fitness parameters. Study I Subjects were 22 female officer and enlisted personnel aged 24 to 34 years (mean = 28.2). The women followed a 10-week A/CWT program working at an intensity of 60% of determined one repetition maximum (1RM). These women showed significant (p less than 0.05) improvements in dynamic muscular strength, muscular endurance, and stamina. Only upper torso static strength was unaffected by training. Study II Participants were 115 female recruits aged 17 to 34 years (mean = 20.4). They were randomly assigned to one of three training groups: 1) aerobic/calisthenic training (A/CAL) (N = 58); 2) aerobic/circuit weight training at 40% (A/CWT-40) of maximum strength determined for a single repetition (1RM) of the lifting exercises (N = 26); and 3) aerobic/circuit weight training at 70% (A/CWT-70) of determined 1RM (N = 30). Results showed that standard recruit A/CAL training did not significantly (p less than 0.05) enhance upper torso dynamic strength (except the lat-pulldown test) or stamina. A/CWT-70 elicited significantly (p less than 0.05) higher gains in several tests of upper torso strength than A/CAL or A/CWT-40. These results suggest that A/CWT offers a way to develop the required upper torso strength of Navy women.

Adult↗
PubMed1985

Aerobic/calisthenic and aerobic/circuit weight training programs for Navy men: a comparative study.

Study I. Participants were 43 Navy men (mean age = 32.1 yr) assigned to one of three exercise training protocols: aerobic/circuit weight training performed at either 40 or 60% of determined one-repetition maximum strength or aerobic/calisthenic training. During the 10-wk study, each exercise group participated in three training sessions per week performed on alternate days. The results of this study indicate that dynamic strength (both upper and lower) increased for the aerobic/circuit weight training groups but not for the aerobic/calisthenic group. With the exception of bench press endurance for the aerobic/calisthenic group, all groups showed significant increases in muscular endurance and stamina. No significant changes were seen in static strength or flexibility in any of the groups. Study II. Subjects were 87 male Navy personnel (mean age = 19.8 yr) receiving basic training at the Recruit Training Command, San Diego, CA. One company of recruits (N = 41) participated in an experimental aerobic/circuit weight training program at 70% of determined one-repetition maximum. A second company (N = 46) received the standard Navy recruit physical training program (aerobic/calisthenic training). During the 8-wk study, both groups participated in an identical running program performed three times per wk on alternate days. Additionally, aerobic/circuit weight training participants completed two circuits (1 circuit = 15 exercises) three times per wk on alternate days to running. Study findings show the experimental aerobic/circuit weight training program produced significantly greater dynamic muscular strength and muscular endurance changes than the standard aerobic/calisthenic program.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Excretion of Leptospira interrogans serovar hardjo following calving or abortion.

Leptospira interrogans serovar hardjo was demonstrated in the vaginal discharges of 12 experimentally infected heifers for up to eight days after abortion or calving. Organisms were recovered from the oviducts of heifers examined at slaughter eight to 22 days after calving or 32 to 91 days after infection. They were also recovered from the uteri of four heifers eight to 22 days after calving.

Abortion, Veterinary↗
PubMed1984

Contagious equine metritis--use of gas liquid chromatography in identifying the causal agent.

Cellular fatty acid compositions of contagious equine metritis isolates and three reference Haemophilus equigenitalis cultures were determined by gas chromatography. The chromatographic data were standardised and normalised fatty acid methyl ester (FAME) profiles were produced. The profiles were compared visually and similarity indices were determined using a computer peak matching method. There was little difference between the profiles of the three reference strains, each strain being characterised by three major fatty acids; C 18:1, C 16:0 and 30H-C 14:0. Variations in cultural conditions had no significant effect on the FAME profiles. The identification of laboratory isolates using the technique was in agreement with the presumptive identification based on the currently recommended tests and an improvement on the confirmatory serological identification. The FAME profiles provided confirmation of identity where it was not possible to use the presently recommended serological procedures. The authors recommend the gas chromatography technique for use in the diagnostic laboratory as an adjunct to the presently accepted identification methods.

Animals↗
PubMed1983

Leptospiral infection in horses in Northern Ireland: serological and microbiological findings.

Thirteen strains of pathogenic leptospires were isolated from 12 of 91 horses; seven strains belonged to the Australis serogroup (serotype bratislava) with three, two and one strains belonging to the Icterohaemorrhagiae, Hebdomadis (serotype hardjo) and Autumnalis serogroups respectively. Using leptospires isolated from horses and others representing the known parasitic Leptospira serogroups, a sample of 650 mares' sera was tested for agglutinating antibodies. Antibodies were found in 89.1 per cent of sera. The predominant reaction was to serotype bratislava, strain S/1334/79, isolated in this study, antibodies to which were detected in 81.8 per cent of sera. It is suggested that serotype bratislava may be adapted to, and maintained by, the horse population in Northern Ireland.

Animals↗