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Biomedical subjects

L E Evans

Publications and source records attributed to L E Evans.

At least 19 recordsLinked to original sources
PubMed1997

A novel surgical technique for vasectomizing boars.

A novel surgical technique was used for vasectomizing boars. The benefit of this approach over existing methods is that the ductus deferens is isolated prior to its entrance into the spermatic cord, thereby eliminating the potential for damage to associated neurovascular structures that are essential to testicular viability. Additionally, the described surgical procedure can be performed on boars positioned in lateral recumbency. Vasectomized boars can be used in breeding management strategies.

Anesthesia, General↗
PubMed1997

Removal of the caudae epididymides to create infertile boars for use in estrus detection programs.

Epididymectomies (removal of the caudae epididymides) were performed to create infertile boars. The simplicity of this procedure allowed for it to be easily performed on physically or chemically restrained boars that weighted 30 kg. Benefits of the use of epididymectomy, rather than vasectomy, to render boars infertile include low cost, simplicity, reduced surgical time, and minimum need of surgical instruments and materials. Epididymectomized boars are used in swine breeding management programs.

Animals↗
PubMed1994

Excretion of porcine reproductive and respiratory syndrome virus in semen after experimentally induced infection in boars.

Four boars intranasally inoculated with porcine reproductive and respiratory syndrome (PRRS) virus were monitored for 56 days after exposure for changes in semen characteristics and for the presence of virus in the semen. Clinically, 2 of 4 boars had mild respiratory signs of 1 day's duration after infection. Changes in appetite, behavior, or libido were not detected. All boars seroconverted on the indirect fluorescent antibody and serum virus neutralization tests by day 14 after inoculation. Virus was isolated from serum between days 7 and 14 after inoculation. During the monitoring period, semen volume decreased and pH correspondingly increased; however, this change began 7 to 10 days prior to infection. Differences in sperm morphologic features, concentration, or motility between the preinfection and postinfection samples were not observed. The PRRS virus was detected in semen at the first collection in each of the 4 boars (ie, 3 or 5 days after challenge exposure). Virus was detected in nearly all semen samples collected from the 4 infected boars through days 13, 25, 27, and 43, respectively. Neither gross nor microscopic lesions attributable to PRRS virus were observed in tissues collected at the termination of the experiment (day 56), and virus isolation results from reproductive tissues were negative.

Animals↗
PubMed1994

Medically treated miscarriage in Alamance County, North Carolina, 1988-1991.

The authors attempted to identify all medically treated miscarriages in Alamance County, North Carolina, between September 1988 and August 1991. Clinical and demographic characteristics of the cases were evaluated, and risks were calculated in relation to total pregnancies, including induced abortions. Miscarriage cases usually had positive pregnancy tests, and a sizable proportion (66% of whites, 72% of blacks) had a pathology report indicating the presence of a conceptus. Nineteen percent of the cases were identified in hospitals, a more common source for women who were unmarried, young, of low education, and had pregnancies of advanced gestational age. The risk of medically treated miscarriage was 7.7% among whites and 5.5% among blacks, with higher risks among older women. The lower risk among blacks, especially those with lower levels of education, suggests underascertainment, possibly resulting from a failure to seek treatment.

Abortion, Spontaneous↗
PubMed1993

Transoral axial division, under endoscopic guidance, for correction of epiglottic entrapment in horses.

Transoral axial division was performed, using endoscopic guidance, in 20 horses with epiglottic entrapment. Mean age of affected horses was 3 years (range, 2 to 5 years), and there were 18 Standardbreds and 2 Thoroughbreds. Standardbreds and female horses were significantly overrepresented when compared with a reference population. Upper respiratory noise prompted endoscopic examination before surgery in 16 horses, but noise was not heard in 4 horses. Ten horses had entrapment by thin tissue without ulceration, 6 horses had entrapment by thin tissue with small, partial-thickness ulceration, 3 horses had entrapment by moderately thick tissue with large, partial-thickness ulceration, and 1 horse had entrapment with thick tissue and severe ulceration. After surgery, horses received anti-inflammatory medication and box stall rest with hand walking for 7 days. All horses returned to race training on day 7 after surgery and returned to their previous level of racing or training. Epiglottic entrapment recurred in 2 horses (10%), and dorsal displacement of the palate developed in 2 horses after surgery. Relationship of epiglottic entrapment and dorsal displacement of the palate to epiglottic hypoplasia was not apparent. Transoral axial division under endoscopic guidance appeared to be a useful, safe, and economic alternative to currently available methods for management of epiglottic entrapment in horses. Horses with entrapment by thick and ulcerated tissue may be best managed by surgical resection of entrapping tissue.

Animals↗
PubMed1993

Episodic scrotal mutilation with concurrent bilateral sperm granuloma in a dog.

Bilateral sperm granuloma with diffuse spermatocele was found to be the cause of infertility in a young Golden Retriever. Anamnesis indicated that the dog had intermittent episodes of self-inflicted ulcerative scrotal dermatitis, beginning when it was 4 to 5 months old and regardless of season or environment. A complete breeding soundness examination produced consistently azoospermic ejaculates in the presence of bilaterally firm, distinct swellings of the epididymides. Because of the poor reproductive prognosis, the owner requested castration and scrotal ablation. Although scrotal trauma was initially thought to be associated with the onset of sperm granuloma formation, evaluation of the history and physical examination and laboratory findings indicated that a bilateral congenital anomaly was the most likely cause of infertility.

Animals↗
PubMed1993

Fetal dopamine cell survival after transplantation is dramatically improved at a critical donor gestational age in nonhuman primates.

Mesencephalic tissue containing newly generated dopamine neurons was collected from brains of embryonic African green monkeys at 44 and 49 days of gestation and stereotaxically implanted into multiple sites in the caudate nucleus of adult monkeys previously treated with the dopamine protoxin, 1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine. Ultrasonography was utilized to assess the developmental stage prior to hysterotomy. Brains were removed for combined histochemical and biochemical analyses at 3 1/2 months after grafting to determine the extent of graft survival and growth. The dopamine content of the target nucleus was assessed from microdissected "punches" placed in proximity to grafts identified in unfixed brain slices prior to fixation. Tissue dopamine levels adjacent to the grafts were elevated markedly, reaching 25-50% of control levels at some sites in the caudate nucleus. Morphometric analysis of graft size and dopamine cell numbers was performed with computer-enhanced, video-based imaging. Exceptionally large grafts that far exceeded their initial size at the time of implantation were seen at each placement site. The dopamine cell count was as high as 3500 in a single graft from E44 tissue, but only as high as 550 from the E49 donor. Up to 15,000 tyrosine hydroxylase-positive neurons were stained in the host monkey that received E44 tissue; only 1/10 as many were seen in each of the recipients of E49 day samples. The earlier donor grafts occupied as much as 15% of the caudate nucleus as seen in a single coronal section; summation of all sections that contained grafts at each placement from the E44 donor revealed average areas occupied by the grafts ranging from 3 to 8% of the caudate nucleus. In comparison, grafts produced from an E49 donor averaged between 2.4 and 5.4% of the area of the target. Qualitatively, grafts from each gestational stage showed well-developed dopamine neurons with morphological characteristics equivalent to those of all three ventral mesencephalic dopamine cell groups. The attainment of large, well-differentiated grafts with thousands of dopaminergic neurons from early gestation tissue suggests that optimal cell survival in primates is dependent on the degree of postgerminal development of the dopamine neuron. Neurite extension may be critical in this regard as well as other, at present, undefined factors. Maximal graft development and cell survival may be a critical element in the ability of neural grafts to reverse a neurological disability and to maintain improvement in the event of continued degeneration of host dopamine neurons.

Animals↗
PubMed1991

Effect of latex and vinyl examination gloves on canine spermatozoal motility.

Two experiments were conducted to determine whether contact with latex or vinyl examination gloves affects canine spermatozoal motility. In experiment 1, semen was collected by digital manipulation from each of 5 dogs, and initial spermatozoal motility was assessed. The ejaculate was divided into 5 equal subsamples of 2 ml each, then randomly assigned to a control group, or treated with a 0.5-cm2 piece of latex or vinyl glove with or without talcum powder. After such exposure, spermatozoal motility was assessed at 1 and 5 minutes. Talcum powder within latex or vinyl glove treatments had no significant effect on spermatozoal motility at either period. Spermatozoal motility in samples did not differ between the control and vinyl glove groups; however, latex glove-treated samples were found to have a significant (P less than 0.05) decrease in spermatozoal motility at 1 and 5 minutes. In experiment 2, the effects of latex and vinyl gloves on canine spermatozoal motility during a sham laboratory manipulation was performed. Three ejaculates of approximately 10 ml were collected from each of 5 dogs and randomly assigned, within each dog, to be either a control (no glove exposure) or allowed to briefly contact either a latex or vinyl glove during sample manipulation. Spermatozoal motility was assessed for each sample immediately prior to and at 1 minute after manipulation. Exposure of semen to latex gloves significantly (P less than 0.05) decreased sample spermatozoal motility, whereas vinyl glove exposure had a minimal (P greater than 0.05) effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1991

Surgical treatment of uterine torsion in a llama (Lama glama).

A multiparous llama was presented because of failure to proceed into the second stage of labor. Clockwise uterine torsion and a live fetus were identified by rectal and vaginal examinations. A cesarean operation was elected because of the prolonged first stage of labor and lack of cervical dilatation. Anesthesia was induced with a 10% guaifenesin solution administered intravenously via a pressurized pump followed by intubation and maintenance with 2% halothane. A ventral midline surgical approach exposed the uterus and the fetus was removed through a uterotomy. The placenta was manually stripped from the myometrial edges of the incision and the margins were oversewn using a continuous interlocking pattern. The uterus was then closed using a continuous Utrecht pattern and the uterus rotated 180 degrees back to its normal anatomical position. The abdomen was closed in 3 layers. Recovery of the llama was uneventful with the male cria able to nurse 6 hours post-operatively. Placental expulsion occurred approximately 48 hours after fetal removal.

Anesthesia, Intravenous↗
PubMed1990

Electroejaculation and artificial insemination in Vietnamese potbellied miniature pigs.

A 15-month-old Vietnamese miniature boar was examined because of suspected infertility. A breeding soundness examination was conducted, using electroejaculation under anesthesia for semen collection. Semen values were normal despite a subpubic location of the testes. Artificial insemination of a gilt with extended semen resulted in the birth of a litter 111 days later. Vietnamese potbellied boars have small and sometimes nearly undetectable scrotal pouches, which may cause the producer to question the fertility of the boars.

Animals↗
PubMed1988

Prescribing patterns in agoraphobia with panic attacks.

Although medication is used commonly in the treatment of agoraphobia with panic attacks, the actual drug-prescribing patterns of the medical profession have not been well studied in this condition. The present study compares the prescribing patterns of general practitioners and psychiatrists in their treatment of agoraphobia with panic attacks. The medical records of 111 agoraphobic patients with panic attacks were analysed and divided into those who were referred by general practitioners and those who were referred by psychiatrists. Over all, in the treatment of agoraphobia with panic attacks, general practitioners prescribed drugs less often than did psychiatrists. They used fewer combinations of drugs and tended to prescribe tricyclic antidepressant agents in doses which generally are considered to be below the therapeutic range. This finding would suggest that general practitioners are less effective than are psychiatrists in prescribing for this condition as judged by current practice, although they are less likely to prescribe combinations of drugs--a practice which might well be to their credit.

Adult↗
PubMed1984

Testicular changes observed in boars following experimental inoculation with pseudorabies (Aujeszky's) virus.

Four boars were inoculated intranasally with pseudorabies virus to determine if microscopic testicular changes occurred as a result of infection. Testicular biopsies and semen samples were taken at two, four and six weeks postinoculation and the boars were castrated immediately after the last sample collection. Testicular samples and semen were cultured to determine if the virus was present. Pseudorabies virus was not isolated from the semen or testicular tissue. Virus was isolated from trigeminal ganglia at necropsy and from nasal swabs taken one day after castration. Consequently, a time of high risk for shed of the virus from clinically normal carrier animals is immediately following castration. Gross changes were not observed in testicular tissues and microscopic changes in the testicles were the result of biopsy. Lesions consistent with pseudorabies virus infection were observed in the central nervous system of all inoculated boars. Temporary lowered fertility may result from the effects of elevated body temperature on spermatogenesis during acute clinical disease. However, it appears that the strain of pseudorabies virus used, lacked the ability to infect and/or replicate in the boars' reproductive tracts.

Animals↗
PubMed1984

The effect of pseudorabies (Aujeszky's) virus infection on young mature boars and boar fertility.

This study was designed to determine the effects of experimental inoculation with pseudorabies virus on the reproductive tracts of young adult boars. Pseudorabies virus was inoculated intranasally into 12 boars and intrapreputially into four boars. All animals seroconverted after nasal or preputial inoculation. Semen abnormalities were observed 21 days postinoculation with partial recovery by 50 days postinoculation. Virus was isolated from the preputial sheath of two intrapreputially inoculated boars 12 days postinoculation. It was concluded that pseudorabies virus infection can be established via preputial inoculation and that decreased spermatogenesis and infertility can result.

Animals↗
PubMed1983

Antigenic relationships among some bovine rotaviruses: serum neutralization and cross-protection in gnotobiotic calves.

A method was further developed to screen non-tissue-culture-adapted bovine rotaviruses for serotype, using a neutralization test with infectious fecal rotavirus. One of those rotaviruses (B223) which was not blocked by antiserum to the neonatal calf diarrhea virus (NCDV) serotype was then adapted to cell culture in the presence of the antiserum for two or more passages and hyperimmune antiserum to this isolate had a 60-fold-higher homologous neutralization titer than with the NCDV serotype rotavirus. Seventy-three isolates were serotyped and eight (11%) were not of the NCDV serotype (bovine rotavirus serotype I). Of these eight, five belonged to the new bovine rotavirus serotype II and three were not typed, indicating the existence of one or more further serotypes. Cross-protection studies in gnotobiotic calves showed that cross-protection only occurred between rotaviruses of the same serotype, and even a minor serotype difference was sufficient for the calves to show a lack of cross-protection. The serotypes (I and II and the three untyped isolates) also showed differences in the rate of migration in polyacrylamide gel electrophoresis of some of their RNA segments (no. 4, 6, 7, 8, 9, 10), indicating that they were of different electropherotypes.

Animals↗
PubMed1981

Comparison of sperm-rich fractions of boar semen collected by electroejaculation and the gloved-hand technique.

Semen was collected from 8 yearling boars, using electroejaculation and the gloved-hand technique. Four semen samples were collected from each boar by each technique, on an alternating schedule, with a 72-hour interval between collections. Comparison of the volume, motility, live-dead ratio, sperm concentration, and spermatozoal conformation of the sperm-rich fractions showed that there were no significant differences between the 2 techniques for any factor evaluated.

Animals↗
PubMed1981

Expanded polytetrafluoroethylene femoropopliteal grafts: forty-eight-month follow-up.

Ninety-eight expanded polytetrafluoroethylene (PTFE) grafts were used for femoropopliteal reconstruction in 81 patients. Forty-eight-month follow-up is now available for 20 grafts and 36-month follow-up is available for 51 grafts. Seventy-four percent of the patients were men. Thirty-one percent had diabetes mellitus, 38% had hypertension, 36% had atherosclerotic heart disease, 18% had prior myocardial infarction, 17% had a previous operation for aortoiliac disease, and 14% had a previous ipsilateral femoropopliteal bypass procedure. The indication for operation was claudication in 47%, rest pain in 20%, and ischemic pregangrene or gangrene in 32% of patients. Distal runoff was angiographically graded as good (76%) or poor (24%). Seventy-three grafts were anastomosed to the proximal or midpopliteal artery (above the knee); 25 grafts were anastomosed to the distal popliteal artery (below the knee). Graft occlusion was determined by the return of ischemic symptoms, disappearance of previously palpable pulses, or by angiographic or Doppler assessment. There were no operative deaths. Nonocclusive causes of graft loss were death (7), amputation (2), infection (2), and aneurysm (5). The overall cumulative patency rate calculated by the life-table method, according to the criterion of occlusion alone, was 75% at 6 months, 68% at 2 years, 58% at 3 years, and 48% at 4 years. Preoperative symptoms, the number of patent outflow vessels, popliteal anastomosis placed above or below the knee, or hypertension did not adversely affect graft patency. Diabetes mellitus was associated with significantly increased graft failure. The PTFE graft is an acceptable alternative for femoropopliteal reconstruction for the patient without a suitable autologous saphenous vein.

Aged↗