Biomedical subjects

J C Wright

Publications and source records attributed to J C Wright.

At least 73 records · Page 4Linked to original sources

PubMed1993

Use of prostaglandin products by dairy cattle owners, beef cattle owners, and veterinarians.

Questionnaires regarding the use of prostaglandin F2 alpha and its analogues (hereafter referred to as PG) were sent to 332 Alabama beef cattle owners and to 279 Alabama dairy cattle owners after attempting to contact them by telephone to request their participation in the survey. Questionnaires concerning the use of PG in their clients' herds were likewise sent to 147 food animal and mixed animal practitioners in Alabama after attempting telephone contact. Response among beef cattle owners, dairy cattle owners, and veterinarians to whom questionnaires were mailed was 64.5, 61.6, and 75.5%, respectively. Only 7.4% (13 of 175) of respondent beef cattle owners reported use of PG in their herds, and this use was predominantly for artificial insemination and embryo transfer. In contrast, 66.5% (109 of 164) of respondent dairy cattle owners reported use of PG, generally with satisfactory results, for some of the following conditions: unobserved estrus (n = 77), uterine infections (n = 74), retained placenta (n = 65), cystic ovaries (n = 56), estrus synchronization (n = 45), and induction of parturition (n = 13). Although 94.9% of respondent veterinarians treated cattle with PG, those attending beef herds thought that more important strategies were available for improvement of beef cattle productivity than increased use of PG. Among these strategies were shorter calving seasons, improved nutrition, better record keeping, more frequent herd health visits, improved animal identification, and increased use of bull breeding soundness examinations.(ABSTRACT TRUNCATED AT 250 WORDS)

Agriculture↗

PubMed1993

Use of in vitro fertilization for production of calves from involuntary cull cows.

PURPOSE: The main purpose of the study was to assess the feasibility of a combined system for in vitro maturation of oocytes, in vitro fertilization, and in vitro culture of embryos for production of calves from cows that have to be removed prematurely from production units. RESULTS: Eighteen cows that were to be culled from experimental dairy production units were ovariectomized. An average of 45.7 oocytes per cow was collected from the ovaries. After in vitro maturation and fertilization of the oocytes, an average of 40.8 presumptive zygotes was placed into in vitro culture, with an average of 16.1 cleaving by day 2 and an average of 5.7 developing to morulae/blastocysts by day 6 or 7. A greater mean quantity of oocytes was collected from cows that were ovariectomized between day 5 and day 13 of the estrous cycle than from those that were ovariectomized between day 0 and day 3 of the estrous cycle. Correspondingly larger mean numbers of cleaved zygotes and morulae/blastocysts were produced from the cows that were ovariectomized between day 5 and day 13 of the cycle. Transferable embryos were produced from 17 of the 18 cows. Eighteen embryos from six oocyte donor cows were transferred to recipients. Six of the eighteen recipients were confirmed to be pregnant after 40 days. Three of the pregnant recipients delivered live calves at term. Two others remain pregnant but have not reached term. The sixth recipient aborted at approximately 120 days of gestation. CONCLUSIONS: Results from the preliminary study indicate that this system can be used for production of calves from cull cows. Although transferable embryos were produced from all except one cow, there was a high degree of variability among cows in total number of oocytes recovered and embryos produced. More donors need to be evaluated to determine the effects of age, breed, reason for culling, and source of semen.

Animals↗

PubMed1993

Differentiation of benign from malignant breast masses by time-intensity evaluation of contrast enhanced MRI.

Using gadolinium-DTPA enhanced MRI we analyzed the enhancement characteristics of palpable breast masses in 23 patients--10 cancers and 13 benign lesions. The most specific finding for separating benign from malignant lesions was a ratio of maximum intensity change divided by the time interval during which this first occurred. Designated ranges of this ratio were specific for benign disease and sensitive for malignancy in this small patient group. Three of eight fibroadenomas exhibited enhancement patterns indistinguishable from cancer.

Adenofibroma↗

PubMed1993

Measurement of left ventricular mass in hypertrophic cardiomyopathy using MRI: comparison with echocardiography.

Left ventricular mass (LVM) is an important consideration in the management of cardiac hypertrophy associated with hypertrophic cardiomyopathy (HCM), systemic hypertension, and other diseases. A brief MRI cardiac imaging procedure used to monitor regression of LVM during treatment would be beneficial in management of these patients, since echocardiograms cannot be obtained in all patients and since the volume of a hypertrophic heart can straightforwardly be assessed from a series of tomographic slices. The present study was designed to evaluate a brief cardiac MRI procedure for measurement of LVM in HCM and compare it to echocardiography. MRI images acquired in a simulated transverse body plane were used to evaluate the mass of the left ventricle in 6 ex vivo human hearts obtained at autopsy. The estimates of LVM by MRI in the ex-vivo hearts were within 8% of the actual LVM. MRI images were acquired to evaluate LVM in 5 normal subjects and 12 patients diagnosed with HCM. Echocardiography was accomplished on 4 of the normal subjects and 10 of the patients having HCM. There were no significant differences in LVM by MRI and echocardiographic techniques in normal subjects. Transverse MRI images acquired on normal subjects demonstrated that estimates of LVM are reproducible when repeated over 3-w to 3-mo intervals. Images selected for analysis represented the heart in an early diastolic phase. MRI and echocardiographic techniques demonstrated significant differences in LVM in HCM patients. Estimates of LVM in normal subjects and patients diagnosed with HCM were normalized for body weight. The LVM estimates for HCM patients were very significantly different than normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Weight↗

PubMed1993

The role of situational demands and cognitive competencies in behavior organization and personality coherence.

Consistency in the natural organization of aggressive and prosocial (constructive) behavior, assessed repeatedly in vivo over a summer in a residential camp for children, was predicted from situational and personal characteristics. Similarity of situations in the types of competencies they demand in part predicted cross-situational consistency in individual differences in aggressive behaviors (Study 1). Study 2 examined the effect of cognitive competence on the discriminative patterning of behavior variation across situations. More cognitively competent Ss showed such discriminative patterning, which was reflected in greater Person X Situation interaction variance in their prosocial behavior.

Aggression↗

PubMed1993

Scanning electron microscopy of intraocular lenses that had been implanted in dogs.

Scanning electron microscopy was used to evaluate changes on the surfaces of polymethylmethacrylate (PMMA), silicone, and polyhydroxyethylmethacrylate (HEMA) intraocular lenses (IOL) that had been implanted in the anterior chambers of the right eyes of 15 dogs. Five dogs received PMMA IOL; 5 dogs received silicone IOL; and 5 dogs received HEMA IOL. Twenty-eight days after surgery, the IOL were removed and processed for scanning electron microscopy. Nonimplanted IOL of each type were processed identically for comparison. Implanted PMMA IOL had significantly more debris and macrophages on their surfaces than did silicone IOL or HEMA IOL. Silicone IOL had significantly less fibrin deposition than did PMMA or HEMA IOL. Silicone IOL had surface defects attributable to handling by surgical instruments. Implanted HEMA IOL had multiple pits that appeared to be caused by biodegradation.

Animals↗

PubMed1993

Development of a DNA probe for identification of bovine herpesvirus 4.

A sensitive and specific DNA probe for detection and identification of bovine herpesvirus 4 (BHV-4) was developed. Cloned fragments from a library of HindIII fragments of the BHV-4 (DN-599) genome were labeled with 32P or digoxigenin and were tested for sensitivity and specificity in detecting viral DNA by dot-blot hybridization. Two probes were identified that detected 10 pg of purified viral DNA, and detected viral DNA in 0.001 micrograms of total DNA extracted from BHV-4-infected cells. Both probes labeled with 32P and 1 labeled with digoxigenin detected viral DNA in samples prepared from cells infected with 2 prototype strains (DN-599 and Movar 33/63) and 4 field isolates of BHV-4. The DNA probes did not hybridize to total DNA prepared from uninfected bovine cells or from cells infected with BHV-1, BHV-2, alcelaphine herpesvirus 1, pseudorabies virus, or equine herpesvirus 1. One probe, labeled with digoxigenin, was tested further by dot-blot hybridization with infected cell lysates that were simply treated with sodium dodecyl sulfate and proteinase K prior to application to the membrane, avoiding extensive DNA purification procedures. This simplified procedure also resulted in specific detection of field isolates of BHV-4 and prototype strains of BHV-4.

Animals↗

PubMed1993

Corneal thickness measured by ultrasonic pachymetry in cats.

Ultrasonic pachymetry was used to measure central, superior peripheral, and temporal peripheral corneal thickness of 35 cats (70 eyes) with normal corneas, anterior chambers, and intraocular pressures. Mean central corneal thickness for both eyes in 3 locations for 35 cats was 578 +/- 64 microns. Significant differences did not exist between central and peripheral corneal thickness. Corneal thickness increased significantly (P < 0.0001) with age up to 100 months. There was no significant difference in corneal thickness with regard to sex of the cats when adjusted for age.

Animals↗

PubMed1993

Clinicopathologic findings after experimental implantation of synthetic intraocular lenses in dogs.

Clinical findings indicate that canine eyes tolerate implantation of polymethylmethacrylate (PMMA) intraocular lenses (IOL) well, although inflammation and ocular damage attributable to the implants is not known. The use of silicone or polyhydroxyethylmethacrylate (HEMA) IOL has not been reported in dogs. In this study, 15 conditioned, mixed-breed dogs were allotted to 3 groups: 5 received PMMA IOL; 5 received silicone IOL; and 5 received HEMA IOL. The IOL optic was inserted into the anterior chamber of the right eye and anchored to the cornea. An identical surgical procedure was done on the left eye, except that no lens optic was inserted. Clinical examination and measurement of corneal thickness were done immediately prior to and after surgery. Aqueous humor samples were collected at the time of surgery and 28 days after surgery. Only mild and transient inflammation was observed in IOL-implanted eyes. On several postoperative days, it was found that PMMA IOL induced significantly greater corneal thickness, aqueous flare, anterior uveal irritation, and corneal edema than did other IOL. Significantly more anterior uveal irritation and increased aqueous humor protein concentration was observed with HEMA IOL than with PMMA or silicone IOL. Silicone IOL induced significantly less fibrin deposition than did PMMA or HEMA IOL.

Analysis of Variance↗

PubMed1992

Orbital neoplasms in cats: 21 cases (1974-1990).

Squamous cell carcinoma was the most common neoplasm found in a review of case records of 21 cats with histopathologically confirmed orbital neoplasms. Other neoplasms found were lymphosarcoma, undifferentiated carcinoma, malignant melanoma, adenocarcinoma, fibrosarcoma, chondroma, and hemangiosarcoma. Three (14%) neoplasms were primary, 15 (71%) were secondary, invading the orbit from adjacent tissues, and 3 (14%) were a manifestation of multicentric disease. The most common clinical sign was exophthalmia, followed by chronic epiphora, enophthalmia, and strabismus. Mean survival time after diagnosis was 1.9 months. Ten cats were euthanatized at the time of diagnosis because of extensive disease. Mean survival time of the other 11 cats was 4.3 months. Skull radiography was helpful in diagnosing orbital neoplasms in 8 of 11 cats that had invasion of the orbit by adjacent neoplasms.

Adenocarcinoma↗

PubMed1992

Comparison of four erythrocyte fragility tests as indicators of vitamin E status in adult dogs.

Plasma alpha-tocopherol (alpha-T) concentrations, erythrocyte osmotic fragility and detergent sensitivity were measured at 8 week intervals in two 1-year-old male beagle dogs fed a vitamin E-deficient diet (< 0.08 mg per kg alpha-T) and in two control beagles fed the same diet supplemented with vitamin E (> 90 mg per kg alpha-T). Beginning at 24 weeks, dialuric acid haemolysis and spontaneous haemolysis were evaluated also. In the vitamin E-deficient dogs, plasma alpha-T concentrations declined progressively from baseline values of 20.5 and 31.3 micrograms per ml to 0.11 and 0.07 micrograms per ml, respectively, by 90 weeks. The supplemented dogs maintained alpha-T concentrations between 18.3 and 38.4 micrograms per ml. Both dialuric acid haemolysis (R = -0.89) and spontaneous haemolysis (R = -0.91) increased with declining plasma alpha-T concentration. In the dialuric acid haemolysis assay, 50 per cent haemolysis occurred when plasma alpha-T declined to 1.7 micrograms per ml, compared with spontaneous haemolysis in which 50 per cent haemolysis occurred when plasma alpha-T declined to 0.5 micrograms per ml. Osmotic fragility and detergent sensitivity remained unchanged in the vitamin E-deficient dogs throughout the study. Of the four tests, dialuric acid haemolysis was the most sensitive in-vitro assay for vitamin E deficiency in adult dogs.

Animals↗

PubMed1992

The effects of FSH-priming and dominant follicular regression on the superovulatory response of cattle.

Thirty superovulatory treatments were administered to 19 mixed-breed, nonlactating cows. In 10 superovulatory treatments, the cows were primed with follicle stimulating hormone (FSH) on the second and third day of the estrous cycle, and in another 10 superovulatory treatments, the cows received no priming dosage of FSH. Initiation of the superovulatory treatments in both groups was determined by ultrasonically monitoring for regression of the dominant anovulatory follicle. Still another 10 superovulatory treatments were begun on Day 10 without regard for regression of the dominant anovulatory follicle and without a priming dosage of FSH. The mean days for starting the superovulatory treatment in the FSH-primed cows, in the nonprimed cows and in the controls were 10.5, 11.9 and 10 days, respectively. All cows were treated with eight injections of FSH at 12-hour intervals in a declining dosage (36 mg total). Cows were bred naturally and embryos collected nonsurgically seven days later. There was no significant difference (P>0.05) between the total number of embryos or transferable embryos in the three treatment groups. In this study neither priming on Days 2 or 3 nor initiating the superovulatory treatment, based on the morphologic regression of the dominant anovulatory follicle, was an effective means for improving the superovulatory response in cattle.

Journal Article↗

PubMed1992

Redistribution of air within the lungs may potentiate "fright" bradycardia in submerged crocodiles (Crocodylus porosus).

1. Voluntary undisturbed dives by Crocodylus porosus were short in duration (3.08 +/- 1.87 min, mean +/- SD) and accompanied by a small but significant bradycardia (14.3 +/- 5.9% drop). 2. When crocodiles were disturbed underwater there was a rapid onset of "fright" bradycardia, to 65 +/- 6.0% of surface heart rates and dive durations were prolonged to 19.6 +/- 1.8 min. 3. The development of "fright" bradycardia was not accompanied by any increase in intratracheal pressure or expulsion of lung gas. However, sustained contraction of the abdomen and expansion of the thorax revealed a redistribution of air anteriorly within the lungs. 4. We propose that the redistribution of air within the lungs may generate an afferent signal which potentiates the initiation of a severe, dive-prolonging bradycardia.

Afferent Pathways↗

PubMed1992

Borrelia sp. in ticks recovered from white-tailed deer in Alabama.

Six hundred sixty-five hunter-killed white-tailed deer (Odocoileus virginianus) from 18 counties in Alabama (USA) were examined for ticks. Most of the collections were made at state-operated wildlife management areas. Four species of ticks (n = 4,527) were recovered: the lone star tick Amblyomma americanum (n = 482); the Gulf Coast tick A. maculatum (n = 11); the winter tick Dermacentor albipictus (n = 1,242); and the black-legged tick Ixodes scapularis (n = 2,792). Fifty-six percent of the ticks (n = 2,555) were examined for Borrelia sp. spirochetes using an immunofluorescent, polyclonal antibody assay. Spirochetes were detected in I. scapularis (five females, seven males) from Barbour, Butler, Coosa, and Lee counties and A. americanum (four males, four nymphs) from Hale, Lee, and Wilcox counties. Area-specific prevalences in ticks were as high as 3.3% for I. scapularis and 3.8% for A. americanum.

Alabama↗

PubMed1992

Evaluation of sodium carboxymethylcellulose for prevention of adhesions after uterine trauma in ewes.

Efficacy of a 1% solution of sodium carboxymethylcellulose (CMC) infused into the peritoneal cavity of ewes was evaluated for prevention of intraperitoneal adhesions resulting from surgery of the reproductive tract. Six ewes were assigned to each of 4 groups. Group-1 ewes were controls that underwent ventral midline celiotomy and exploration of the abdominal viscera. Group-2 ewes were treated similarly to group-1 ewes, except that a 1% solution of CMC (14 ml/kg of body weight) was infused into the peritoneal cavity. This group was studied to determine whether CMC would cause changes in the peritoneal cavity. Group-3 comprised ewes representing a uterine trauma model. Ewes underwent abdominal exploration, but in addition had a standard embryo collection technique performed on 1 uterine horn and hysterotomy performed on the opposite uterine horn. Group-4 ewes were treated like group-3 ewes, except that, similar to treatment of group-2 ewes, CMC was infused into the peritoneal cavity. All ewes were euthanatized and necropsied 12 to 14 days after surgery. Abdominal adhesions were evaluated, and an adhesion severity score was assigned to each ewe on the basis of number and severity of the adhesions. Ewes of all groups had abdominal adhesions. Significantly (P less than 0.05) lower adhesion score was observed in ewes given CMC (groups 2 and 4) than in the adhesion model (group 3). Significant difference was not observed in adhesion score when groups 1, 2, or 4 were compared. Though not statistically significant, fewer adhesions were observed in ewes of groups 2 and 4 than in group-1 ewes.

Animals↗

PubMed1992

Efficacy of milbemycin oxime against naturally acquired or experimentally induced Ancylostoma spp and Trichuris vulpis infections in dogs.

The efficacy of milbemycin oxime was evaluated at dosages of 0.25, 0.50, and 0.75 mg/kg of body weight in dogs naturally infected with mature Ancylostoma spp, at a dosage of 0.50 mg/kg in dogs with experimentally induced immature and mature A caninum, and at dosages of 0.55 to 0.86 mg/kg in dogs naturally infected with mature Trichuris vulpis. Milbemycin oxime was 95 and 99% effective against mature Ancylostoma spp at dosages of 0.50 and 0.75 mg/kg, respectively, but only 49% effective at a dosage of 0.25 mg/kg. Efficacy was 49% against pulmonary L3-L4 stages of A caninum (36 hours after inoculation), greater than 80% against L4 (120 hours after inoculation) and early L5 stages (216 hours after inoculation), and greater than 90% against experimentally induced mature stages (360 hours after inoculation). Milbemycin oxime was also 97% effective in the removal of mature Tr vulpis from naturally infected dogs. Adverse reactions were not observed following treatment in any of the dogs.

Ancylostomiasis↗

PubMed1991

Children's auditory and visual processing of narrated and nonnarrated television programming.

Two experiments with 5- and 7-year-old children tested the hypotheses that auditory attention is used to (a) monitor a TV program for important visual content, and (b) semantically process program information through language to enhance comprehension and visual attention. A direct measure of auditory attention was the latency of the child's restoration of gradually degraded sound quality. Restoration of auditory clarity did not vary as a function of looking. Restoration of visual clarity was faster when looking than when not looking. Restoration was faster for visual than auditory degrades, but audiovisual degrades were restored most rapidly of all, suggesting that dual modality presentation maximizes children's attention. Narration enhanced visual attention and comprehension including comprehension of visually presented material. Auditory comprehension did not depend on looking, suggesting that children can semantically process verbal content without looking at the TV. Auditory attention did not differ with the presence or absence of narration, but did predict auditory comprehension best while visual attention predicted visual comprehension best. In the absence of narration, auditory attention predicted visual comprehension, suggesting its monitoring function. Visual attention indexed overall interest and appeared to be most critical for comprehension in the absence of narration.

Attention↗

PubMed1991

Canine aggression toward people. Bite scenarios and prevention.

This article reviews studies of different dog bites directed toward people. Typical bite events are summarized by describing the characteristics of the dog, victim, and wound; serious bites (severe and fatal bites) are described separately. Suggestions for the prevention of dog bites are presented.

Age Factors↗