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Biomedical subjects

L E Evans

Publications and source records attributed to L E Evans.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1978

Drugs and depression.

Moderate or severe depression is now one of the most common diseases of our time with a prevalence of nearly 3%. It seems likely that this prevalence has increased as a result of the wider use of drugs which have an effect on the neurotransmitters. Changes in the levels of these neurotransmitters in the central nervous system are thought to be the biochemical basis for the development of at least some depressive illnesses. Drug-induced depressions are more likely to occur in those individuals who are genetically predisposed to depression or who have had a previous depressive illness. Other groups who are particularly susceptible to these effects are the elderly. Many groups of drugs have a primary or secondary action on the central nervous system neurotransmitter function. Some 200 drugs have been claimed to cause depression in certain patients, but only a relatively small number precipitate depressive symptoms with any frequency. Those most commonly implicated are the long-acting antipsychotics, barbiturates, ethanol, oral contraceptives and antihypertensive agents. It is important to remember that some drugs, such as reserpine, cause depression as a side-effect during their therapeutic use whereas others, such as fenfluramine, cause depression mainly when they are withdrawn too rapidly. In those patients presenting with depression, it is important to review the current drug therapy in order to assess the part played by these drugs in the development of the depression. Following this assessment, drug therapy should be adjusted appropriately. However, a distinction must be made between the symptoms of depression, those physiological changes which occur during treatment with a variety of drugs, and the patient's reaction to the disease for which they are being treated.

Analgesics↗
PubMed1976

Bovine plasma oestrogens, progesterone and glucocorticoids during dexamethasone induced parturition.

Plasma samples were collected from jugular, uterine and utero-ovarian veins during glucocorticoid induced parturition. Plasma oestrogens, corticosteroids and progesterone were determined by competitive protein binding methods. Corticosteroids and progesterone began to decline within 8 to 10 h following DXMS treatment. Corticoids were only temporarily suppressed, while progesterone fell to minimum levels and remained low through calving. At this stage of gestation (270 days) peripheral plasma progesterone was primarily of ovarian origin. Pre-treatment with HCG appeared to support progesterone production by the CL despite DXMS treatment in 2 of 6 cows. These 2 cows failed to calve within the expected 96 h after DXMS. Plasma oestrogens did not show significant increased until 24 h after DXMS treatment. Cows which responded to DXMS treatment (calved) had significantly higher oestrogen levels than those which did not respond. It was concluded that oestrogens probably play a permissive rather than an initiating role in parturition.

Animals↗
PubMed1968

Durum-type wheat with high bread-making quality.

A durum-type wheat (2n = 4x = 28) with high bread-making quality was produced by crossing a durum-wheat variety with a common bread-wheat variety (2n = 6x = 42), backcrossing to the bread-wheat variety for three generations, and then selecting for 28-chromosome plants. The high quality is tentatively attributed to a translocation involving one of the D-genome chromosomes.

Bread↗