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Biomedical subjects

W G Ryan

Publications and source records attributed to W G Ryan.

At least 37 records · Page 2Linked to original sources
PubMed1997

Persistent efficacy of abamectin and doramectin against gastrointestinal nematodes of cattle.

OBJECTIVE: To assess the persistent activity of injectable formulations of abamectin and doramectin against gastrointestinal nematodes of cattle. DESIGN: Controlled slaughter study assessing residual efficacy. PROCEDURE: Nematode-free calves were treated with abamectin or doramectin (each at a dose of 200 micrograms/kg) and infections then induced with repeated doses of infective larvae of Trichostrongylus axei, Haemonchus placei, Ostertagia ostertagi and Cooperia species. The duration of challenge ranged from 14 to 28 days. The calves were slaughtered at either 38/39 or 45/46 days after the treatments and nematodes recovered from the gastro-intestinal tract. RESULTS: Significant reductions in numbers of O ostertagi occurred for both abamectin and doramectin treatments (> 93%) relative to counts in untreated calves, when challenge was administered up to 21 days after treatment. For T axei and Cooperia spp significant reductions occurred when the challenge occurred for 14 days after treatment (99%). Although differences from untreated animals were not significant, the results for H placei suggested high efficacy (> 85%) for up to 21 days for doramectin and up to 28 days for abamectin. CONCLUSIONS: There was no significant difference between abamectin and doramectin for any parasite at any challenge point, indicating that there is equivalent persistent activity of doramectin and abamectin against important gastrointestinal nematodes of cattle.

Animals↗
PubMed1996

Evaluation of ivermectin and milbemycin oxime efficacy against Dirofilaria immitis infections of three and four months' duration in dogs.

OBJECTIVES: To determine the efficacy of ivermectin (IVM) and milbemycin oxime (MBO) against induced heartworm infection, where monthly treatment is started 3 or 4 months after infection, and to monitor microfilaremia and antigenemia. ANIMALS: 21 heartworm-naive Beagles. PROCEDURES: Each of 21 dogs was given 50 infective larvae of Dirofilaria immitis by SC inoculation. One group of 5 dogs served as nonmedicated controls, 2 groups of 5 dogs received IVM at 6 micrograms/kg of body weight or MBO at 500 micrograms/kg for 12 months beginning at postinfection (PI) month 4, and 2 groups of 3 dogs received IVM or MBO for 13 months beginning at PI month 3. Blood collected at intervals not > 1 month beginning at PI month 4 was examined for microfilariae and antigen. Dogs were euthanatized at PI month 16. RESULTS: Adult worm counts, relative to controls, were reduced in the 4-month treatment groups by 95.1 (P < 0.01) and 41.4% for IVM and MBO, respectively. The difference between the IVM and MBO groups was significant (P < 0.01). Live worms were found in all MBO-treated (range, 8 to 27) and control dogs (range, 12 to 39) and in 3 of 5 IVM-treated dogs (range, 2 to 4). In the 3-month treatment groups, worm counts were reduced by 97.7 (P < 0.01) and 96.8% (P < 0.01) for IVM and MBO, respectively. Microfilariae were seen in all control dogs and in only 2 of the 16 treated dogs. The antigen response of MBO-treated dogs in the 4-month treatment group was only slightly weaker than that for control dogs. In all other treated dogs, this response was delayed and weaker. CONCLUSION: Ivermectin is highly (> or = 95%) and significantly more effective than MBO against induced heart-worm infection when 1 year of monthly prophylactic dosing is started 4 months after infection. CLINICAL RELEVANCE: In some cases of owner compliance failure, monthly administration of IVM gives a high level of protection against young adult heartworms.

Animals↗
PubMed1995

The perceived relationship between back symptoms and preceding injury.

A questionnaire was used to gather information regarding the prevalence of minor back symptoms related to performing everyday tasks, including sitting, lifting, etc. in a population of hospital employees. We studied 175 subjects, of whom 111 had not suffered a back injury. Of this group, 68 (61.3 per cent) had suffered back discomfort during or after performing everyday tasks. Sixty-four reported a previous injury to their back, and of these 55 (85.9 per cent) described back discomfort during or after performing everyday tasks. Of the symptomatic cases, 46 (83.3 per cent) maintained that they had no back symptoms prior to their injury, and attributed all of their back symptoms to the injury. The chi 2 test was used to test the null hypothesis that the group attributing their symptoms to injury was derived from the same population as the group who had not suffered any definite injury, and yet had back symptoms. This hypothesis was rejected (P < 0.001), indicating that there was a significant difference between these two groups. We conclude that individuals who sustain a back injury sometimes do not recall that they suffered symptoms prior to their injury. This may be of medico-legal importance in cases where compensation is being sought.

Activities of Daily Living↗
PubMed1994

A failure mechanism of Leeds-Keio ligaments.

From our experience with the Leeds-Keio artificial ligament at Bolton Hospitals we report the histology from three cases in which the new ligament was demonstrated to have failed in response to trivial injury, after an initially successful anterior cruciate replacement. The histology showed fragmentation of graft material associated with a chronic inflammatory response in the new ligament. A chronic inflammatory response occurs as a result of fragmentation of the Dacron fibres; and once established, inhibits production of the neoligament, thus dooming it to failure.

Adult↗
PubMed1994

Altered sexual function and decreased testosterone in patients receiving intraspinal opioids.

Altered sexual function has been reported in individuals addicted to opioids or on methadone maintenance, yet little literature is available regarding the effect of intraspinal opioids on libido or sex hormone levels. We evaluated sexual function and plasma sex hormone levels in six men treated with chronic intraspinal opioids. All patients had some reduction in libido and four patients had difficulty obtaining or maintaining an erection. These changes were noted within 1 month of beginning intraspinal opioid therapy. Serum testosterone levels ranged from 26 to 367 ng/dL (normal, 350-1500 ng/dL); the mean serum level was 197.7 ng/dL (SD = 119.8). Serum testosterone levels and other sex hormones, including follicle-stimulating hormone, luteinizing hormone, sex-hormone-binding globulin, and prolactin, should be measured prior to and at various points during intraspinal opioid therapy. Patients should be queried regarding sexual function and should be cautioned regarding the possibility of these adverse effects prior to initiating spinal opioids. Supplemental testosterone should be considered to treat this dysfunction.

Adult↗
PubMed1994

Back pain in ophthalmologists.

A questionnaire regarding the working practices and incidence of back pain was sent to all 498 consultant ophthalmologists in the United Kingdom. Three hundred and twenty-five (65.3%) questionnaires were analysed by time spent in speciality, and time spent operating each week. One hundred and seventy-four ophthalmologists (54%) had significant attacks of back pain, with the longest-serving consultants having an increased incidence. The number and duration of acute attacks increased with years in speciality but was unrelated to time spent operating. Treatment included analgesics in 97 (56%), physiotherapy in 40 (23%), and 'alternative' medical treatment including osteopathy and chiropraxy in 14 (8%); no treatment was needed in 56 (32%). Investigation and treatment increased with years spent in speciality, 49 (28%) seeking medical advice, usually from a specialist, and 69 (39%) requiring further investigations including plain radiographs, CT scans, myelograms and MRI scans. Nine surgeons needed surgery for back pain.

Back Pain↗
PubMed1994

Histopathological features of failed prosthetic Leeds-Keio anterior cruciate ligaments.

Artificial ligaments such as the Leeds-Keio ligament are inserted into knee joints to treat cruciate ligament trauma. Three cases of prosthetic ligament failure are reported, showing foreign body granulomatous inflammation around implanted fibres, together with abundant fibre particles within giant cells. It is suggested that intra-operative fibre fragmentation can produce a sufficient quantity of dendritic particles to elicit a granulomatous reaction, which can ultimately lead to ligament instability and failure.

Adult↗
PubMed1994

Thyroid function screening in newly admitted psychiatric inpatients.

Thyroid function tests (T4, T3RU, free thyroxine index) were performed upon admission in 269 acute psychiatric patients during a 2-year period. Thyroid disease was detected in 3% and euthyroid abnormalities in 9.3%. T4 and free thyroxine index were significantly lower in depressed patients than those with mania or schizophrenia. The rate of abnormal thyroid tests was lower in this study than in previously reported surveys of psychiatric admissions. Laboratory techniques or differences in population may be responsible for the difference. The differences in thyroid function test values between psychiatric diagnoses are relatively new findings, and appear worthy of investigation.

Adult↗
PubMed1992

Adenocarcinoma metastatic to a growth-hormone-secreting pituitary adenoma: case report.

Although the pituitary gland is known to harbor metastatic deposits, it is a rare occurrence for a metastatic deposit to appear in a pituitary adenoma. A case is presented of an adenocarcinoma metastatic in an acromegalic patient with a pituitary adenoma. This report adds to the literature of the unusual phenomenon of neoplasm-to-neoplasm metastasis.

Adenocarcinoma↗
PubMed1992

Paget's disease of bone and fibrous dysplasia.

This review discusses recent studies of the etiology and epidemiology of Paget's disease of bone, as well as studies of its complications and associations. Medical and surgical treatments are reviewed; agents used in the medical treatment of Paget's disease include pamidronate and other bisphosphonates, gallium nitrate, and plicamycin, among others. The article concludes with a review of various investigations of fibrous dysplasia.

Fibrous Dysplasia of Bone↗
PubMed1991

Apparent beneficial effects of tamoxifen on bone mineral content in patients with breast cancer: preliminary study.

Eight postmenopausal women undergoing adjuvant treatment with tamoxifen (20 mg/day) for breast cancer had baseline pretreatment, and 6- and 12-month post-treatment dual-photon determinations of vertebral bone mineral content (BMC). BMC measured at 6 and 12 months increased over baseline in all subjects. These observations imply that women treated with tamoxifen may retain rather than surrender the protective effect of estrogen against osteoporosis.

Aged↗
PubMed1991

Contraceptive female sterilization in Alabama: a replication of the WHO study.

The prevalence of female sterilization for contraceptive purposes has grown rapidly throughout the world, and is especially high in the United States. Yet the psychosocial impact of female sterilization is incompletely understood. Much of the previous research has been retrospective and has lacked comparison groups of women using other methods. Better designed, prospective studies have been needed, and the World Health Organization's Collaborative Prospective Study of Female Sterilization was conducted to address this need. No evidence was found in the WHO study of a significant impact of tubal ligation compared to other contraceptive methods on mental health, menstruation, or sexual satisfaction. The present study, a replication of the WHO study, compared 323 Alabama women undergoing elective contraceptive sterilization with 318 women using other techniques to control fertility. In general, the results supported the WHO study conclusions. Although sterilization produced a small increase in menstrual distress in Alabama, there were no significant differences between sterilization and comparison women in mental health or sexual satisfaction.

Adult↗