PubMed Health⌕ Search

Biomedical subjects

D H Wallace

Publications and source records attributed to D H Wallace.

At least 19 recordsLinked to original sources
PubMed2000

Potential for cross-transmission of Dictyocaulus viviparus between cattle and white-tailed deer.

Development of an in vitro culture system for infectious Dictyocaulus viviparus larvae made it possible to study the potential cross-transmission of D. viviparus between white-tailed deer (Odocoileus virginianus) and cattle (Bos taurus). Between 26 September 1995-29 February 1996, six parasite-free bull calves were individually inoculated with 15 to 50 infective third stage larvae (L3)/kg of body weight cultured from adult D. viviparus collected from white-tailed deer. Three bull calves were simultaneously inoculated with 45 L3/kg of body weight recovered from cattle either by the Baermann technique or by in vitro culture as above. All three calves inoculated with the homologous cattle strain became patently infected while all six calves inoculated with the heterologous deer strain remained negative for the presence of D. viviparus in the feces and in the lungs upon necropsy.

Animals↗
PubMed1999

Sexual function in 1,202 aging males: differentiating aspects.

BACKGROUND: Late-life sexuality is an important quality-of-life issue that has been minimally explored. This survey seeks to extend our knowledge of the relationship of sexual attitudes and preferences to sexual functioning of a large group of older, community-dwelling men. METHODS: Older men aged 58-94 (N = 1,202) were surveyed with an anonymous self-administered questionnaire including 63 items regarding present and past, actual and desired sexual practices and attitudes. RESULTS: Although age correlated consistently with increased erectile dysfunction and decreased sexual activity, a substantial number of older men continued active sexual behaviors supported by positive attitudes toward sexual function. It was found that both health status and perceived partner's responsiveness are prominent moderators of the age effect. CONCLUSION: In the absence of social isolation and health issues, many older men show persistently active sexual lifestyles as evidenced in their interest and participation in sexual activities. These findings negate a portion of the starkly negative imagery of sexual expression in aging males.

Aged↗
PubMed1999

Safety of omeprazole paste in foals and mature horses.

Omeprazole has been shown to promote healing of spontaneously occurring gastric ulcers in horses when administered for 28 days at a dose of 4 mg/kg bwt/day and to prevent recurrence of ulcers in almost all horses when treatment is continued at a dose of at least 2 mg/kg bwt/day. The purpose of the 3 studies reported here was to 1) evaluate the evolution of potential effects of omeprazole paste (GastroGard), at a dose of 20 mg/kg bwt/day (5x the recommended dose) for 91 days in mature Thoroughbred horses; 2) evaluate the safety in young horses of omeprazole paste when dosed at 4 mg/kg bwt/day (1x), 12 mg/kg bwt/day (3x) or 20 mg/kg bwt/day (5x) for 91 days in Tennessee walking horse foals; and 3) evaluate the safety of omeprazole paste when dosed at 40 mg/kg bwt/day (10x) for 21 days in mature Thoroughbred horses. Within each study, horses were allocated randomly to the control or omeprazole paste treatment group. Clinical examinations, serum biochemistry and haematology were performed at regular intervals until necropsy at the end of the study. There were no treatment-related clinical signs in any treated horse and serum biochemistry and haematology were normal. In conclusion, omeprazole paste is safe for use in horses as demonstrated in studies with foals and mature horses.

Administration, Oral↗
PubMed1999

Physical fitness, aging, and sexuality.

Sexuality is a major quality-of-life issue, even into advanced age. Although relatively few studies have addressed sexuality, most studies have emphasized the decline in both sexual performance and satisfaction with aging. In an effort to assess possible positive modifiers of the decline, we included questions concerning sexuality in a multipurpose 90-item questionnaire submitted to members of the Fifty Plus Fitness Association based in Stanford, California. This group is unique in its commitment to a very active lifestyle and has served as a cohort for many prior studies related to fitness and medical outcomes. Sixty-seven percent of the membership returned the mail questionnaire, and 59% of these respondents replied to the sexually relevant items. The results indicated a high level of sexual activity and satisfaction in both older men and women of the Fifty Plus Fitness Association members. Further, sexual satisfaction seemed to correlate with the degree of fitness. We conclude that physical fitness and high levels of sexual activity are mutually supportive elements of successful aging.

Aged↗
PubMed1998

Efficacy of an in-feed formulation of ivermectin against somatic larvae of Strongyloides ransomi in pregnant swine.

OBJECTIVE: To confirm that ivermectin fed for 7 days to pregnant sows controls transmission of Strongyloides ransomi larvae to pigs via the colostrum or milk. ANIMALS: 24 mixed-breed sows. PROCEDURE: The sows were infected with 250,000 S ransomi larvae on 3 occasions (days 63, 64, or 65, days 71 or 73, and days 78, 79, or 80 of gestation). Eight sows received ivermectin at a dosage of 100 micrograms of ivermectin/kg of body weight/d from days 92 to 99 of gestation, and 8 sows were treated from days 103 to 110 of gestation; 8 remaining sows received unmedicated vehicle. Numbers of S ransomi larvae were counted in samples of colostrum or milk collected 1, 2, and 7 days after parturition. At 7 and 14 days after parturition, fecal samples were collected from each sow and from 4 pigs from each litter for determination of nematode egg counts; at the latter date, pigs were euthanatized and necropsied for worm counting. RESULTS: Pigs born to ivermectin-treated sows had significantly (P < 0.01) fewer adult S ransomi than did those born to control sows; efficacy was 100%. Treated sows had significantly (P < 0.05) fewer S ransomi larvae in colostrum/milk samples taken 1, 2, and 7 days after parturition than did control sows; efficacy was 100%, with the exception of 1 S ransomi larva found in a milk sample from 1 treated sow at 2 days after parturition. CONCLUSION AND CLINICAL RELEVANCE: Ivermectin fed to sows during the last third of gestation at a dosage of 100 micrograms/kg/d for 7 consecutive days is highly efficacious for control of transmission of infective S ransomi larvae to pigs via colostrum or milk.

Animals↗
PubMed1997

Assessment of parasite control and weight gain after use of an ivermectin sustained-release bolus in calves.

OBJECTIVE: To assess parasite control and weight gain after administration of an ivermectin sustained-release bolus over 135 days to calves grazing in the midwestern United States. DESIGN: Replicated pasture study. ANIMALS: 56 Bos taurus calves. PROCEDURE: Calves were matched for body weight and randomly allocated to remain untreated or to receive an ivermectin sustained-release bolus before turnout on day 0. Calves were grazed by treatment group on B pastures (4 replicates). Body weights and fecal egg counts were recorded on days- 1 and 28, and then at 28-day intervals until day 168. RESULTS: Parasitism was not clinically evident prior to or during the study. In treated calves, mean fecal egg counts were at or near 0 at all posttreatment evaluations. Although the mean egg count exceeded 20 ova/g only once in control calves, the cumulative egg output was > 42 million/calf. For the treated group, it was < 0.1% of this number. Mean total weight gain was 33.9 kg (74.6 lb) greater for ivermectin-treated calves than for untreated control calves (P < 0.02): a 34% increase. CLINICAL IMPLICATIONS: Fecal trichostrongyle eggs from calves can accumulate over a grazing season to provide enormous potential for augmenting pasture infectivity. An ivermectin sustained-release bolus (administered to calves being placed on pasture) controls parasitism, limits pasture infectivity, and can substantially influence growth by limiting the impact of subclinical parasitism.

Animals↗
PubMed1997

Evaluation of the persistence of the effect of ivermectin and abamectin against gastrointestinal and pulmonary nematodes in cattle.

The persistence of the effect of ivermectin and abamectin against gastrointestinal nematodes and lungworm in cattle was evaluated in two trials, each involving 28 animals. Groups of seven cattle either remained untreated, or were treated topically with ivermectin at 500 micrograms/kg bodyweight or subcutaneously with either ivermectin or abamectin at 200 micrograms/kg bodyweight. Starting on the day of treatment the cattle were given daily trickle infections with various infective nematode larvae for two weeks (Haemonchus species, Trichostrongylus axei and Cooperia species), three weeks (Ostertagia ostertagi and Oesophagostomum radiatum) and four weeks (Dictyocaulus viviparus). The cattle were killed 49 to 51 days after treatment and their worm burdens measured. An efficacy of > 99 per cent was recorded in all the groups demonstrating that the products controlled Haemonchus species, T axei, C oncophora, C punctata and C surnabada for at least two weeks, O ostertagi and O radiatum for at least three weeks and D viviparus for at least four weeks.

Administration, Topical↗
PubMed1997

Clinical experience with open laparoscopy.

A modified method of open laparoscopy was performed on 568 consecutive patients requiring laparoscopy or laparoscopic surgery. There were no intraoperative complications related to the technique. All patients were reviewed at 1 week following surgery; 4% had minor umbilical sepsis, while none had a postoperative hernia. The modifications to the technique of open laparoscopy described here make it simple and efficient while maintaining the safety inherent with this technique.

Cholecystectomy, Laparoscopic↗
PubMed1997

Randomized trial of different insufflation pressures for laparoscopic cholecystectomy.

BACKGROUND: The factors affecting cardiorespiratory changes and postoperative pain after laparoscopic cholecystectomy are poorly understood. The aim of this study was to assess these changes in patients undergoing laparoscopic cholecystectomy at an insufflation pressure of 7.5 or 15 mmHg. METHODS: Forty patients with similar preoperative characteristics were randomized, 20 to each group. RESULTS: There were no significant differences in intraoperative heart rate or cardiac index although the latter fell significantly soon after insufflation in both groups. The fall in cardiac index lasted longer (7 versus 2 min) and coincided with a slower rise in mean arterial pressure in those having 15 mmHg insufflation. Changes in peak airway pressure, end-tidal carbon dioxide and arterial blood gases were similar. After operation the low-pressure group had significantly less pain, better preservation of pulmonary function and were discharged home sooner (P = 0.015). CONCLUSIONS: Insufflation pressure significantly affects the haemodynamic changes and postoperative pain associated with laparoscopic cholecystectomy.

Carbon Dioxide↗
PubMed1997

Effect of a no-conversion policy on patient outcome following laparoscopic cholecystectomy.

BACKGROUND: One of the potential drawbacks of laparoscopic cholecystectomy is lack of experience with open cholecystectomy. The aim of this study was to examine the effect of a no-conversion policy on patient outcome following laparoscopic cholecystectomy. METHODS: One hundred and sixty-one patients underwent laparoscopic cholecystectomy in the no-conversion period and were compared with 127 operated on during a period in which there was a low threshold for conversion from laparoscopic to open cholecystectomy. All operations in the no-conversion period were performed by surgeons in training assisted by one consultant. RESULTS: One patient in the no-conversion group had a gallbladder carcinoma and the operation was converted to open surgery. All others underwent total cholecystectomy except for one patient who had part of a severely diseased gallbladder left in situ. Operating time was significantly lower, median 65 versus 50 min (P = 0.004), as was postoperative hospital stay, 3 versus 2 days (P = 0.001), in favour of the no-conversion group. There was no bile duct injury and postoperative complications were similar in both groups (6 versus 8 per cent; P not significant). CONCLUSION: Laparoscopic cholecystectomy can be performed safely without converting to open cholecystectomy. As surgeons become more experienced with laparoscopic cholecystectomy, the need to perform open cholecystectomy in an elective setting may disappear.

Adult↗
PubMed1995

Randomized comparison of general and regional anesthesia for cesarean delivery in pregnancies complicated by severe preeclampsia.

OBJECTIVE: To evaluate the maternal and fetal effects of three anesthetic methods used randomly in women with severe preeclampsia who required cesarean delivery. METHODS: Eighty women with severe preeclampsia, who were to be delivered by cesarean, were randomized to general (26 women), epidural (27), or combined spinal-epidural (27) anesthesia. The mean preoperative blood pressure (BP) was approximately 170/110 mmHg, and all women had proteinuria. Anesthetic and obstetric management included antihypertensive drug therapy and limited intravenous (IV) fluid and drug therapy. RESULTS: The mean gestational age at delivery was 34.8 weeks. All infants were born in good condition as assessed by Apgar scores and umbilical arterial blood gas determinations. Maternal hypotension resulting from regional anesthesia was managed without excessive IV fluid administration. Similarly, maternal BP was managed without severe hypertensive effects in women undergoing general anesthesia. There were no serious maternal or fetal complications attributable to any of the three anesthetic methods. CONCLUSION: General as well as regional anesthetic methods are equally acceptable for cesarean delivery in pregnancies complicated by severe preeclampsia if steps are taken to ensure a careful approach to either method.

Adult↗
PubMed1993

Comparison of an ephedrine infusion with crystalloid administration for prevention of hypotension during spinal anesthesia.

This study was designed to compare the efficacy of an ephedrine infusion with crystalloid administration for reducing the incidence of hypotension during spinal anesthesia. Fifty-four ASA I patients scheduled for postpartum tubal ligations under spinal anesthesia were randomly allocated to receive either 15 mL/kg of crystalloid (crystalloid group) or an ephedrine infusion (infusion group). Spinal anesthesia was performed using 70-90 mg of hyperbaric 5% lidocaine. Patients in the infusion group immediately thereafter received an ephedrine infusion at a rate of 5 mg/min for the first 2 min and then 1 mg/min for the next 18 min. The incidence of hypotension was 15/27 (55%) in the crystalloid group and 6/27 (22%) in the infusion group (P < 0.05). There was no significant difference between the groups in relation to the level of anesthesia or maximal heart rate, and hypertension did not occur in either group. We conclude that a prophylactic ephedrine infusion is effective for minimizing and managing hypotension associated with spinal anesthesia and compares favorably with crystalloid administration in this patient population in terms of efficacy and incidence of side effects.

Adult↗
PubMed1992

Effect of type of anesthesia on blood loss at elective repeat cesarean section.

It has recently been reported that the use of halogenated agents during balanced general anesthesia may result in an increase in blood loss associated with cesarean section. This report has been criticized for failure to control for a variety of other factors that may have contributed to the increased blood loss, particularly the indication for and type of cesarean section. The present study was designed in an attempt to resolve this criticism. Blood loss was evaluated in uncomplicated patients undergoing elective repeat cesarean section under either general anesthesia using a halogenated agent (isoflurane) or regional anesthesia (spinal/epidural). All 117 singleton term, nonlaboring women underwent repeat low transverse cesarean section performed through a midline abdominal incision. Exclusion criteria included maternal medical complications, abnormal placentation, polyhydramnios, presence of uterine leiomyomas, and intraoperative complications. Seventy-five patients (64%) received regional and 42 (36%) received general anesthesia. A greater proportion of women undergoing general anesthesia experienced a postoperative decrease in hematocrit of 5 vol% or more compared with patients receiving regional anesthesia (10 of 42 versus 5 of 75, p = 0.018). Thus, we conclude that women undergoing uncomplicated elective repeat cesarean section under general anesthesia supplemented with a halogenated agent are at risk for increased blood loss compared with those women receiving regional anesthesia. However, the increased blood loss was not clinically significant in this study, since none of the patients required transfusion.

Anesthesia, Conduction↗