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Biomedical subjects

D J Patterson

Publications and source records attributed to D J Patterson.

At least 37 records · Page 2Linked to original sources
PubMed1999

Reuse of disposable sphincterotomes for diagnostic and therapeutic ERCP: a one-year prospective study.

BACKGROUND: Although previous studies have documented that single-channel sphincterotomes can be sterilized and used up to 10 times, no studies have prospectively evaluated the reuse of disposable sphincterotomes. METHODS: Five- and six-French double-channel sphincterotomes marketed as one-time-use only were manually cleaned, sterilized with ethylene oxide, and used up to 10 times. Over a 1-year period, total number of uses as a cannulation or cutting device, reason for sphincterotome dysfunction, possible infectious complications were evaluated, and cost-savings associated with reuse were evaluated. RESULTS: The mean number of times sphincterotomes could be used in our institution was 3.4; a broken or stiff cutting wire was the main reason for discard. There were two infectious complications during the study period. Both were experienced by patients with unrelieved obstruction treated with new sphincterotomes. Contingent on the method used, total savings related to sphincterotome reuse was approximately $66,000. CONCLUSIONS: Double-channel sphincterotomes marketed as one-time-use items can be reused safely when properly cleaned. Reuse was associated with significant cost savings in our institution.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1998

Effects of melengestrol acetate on onset of puberty, follicular growth, and patterns of luteinizing hormone secretion in beef heifers.

Our objective was to test the hypothesis that short-term (8 days) treatment of prepubertal heifers with melengestrol acetate (MGA) and subsequent steroid withdrawal would stimulate LH secretion and follicular growth. Angus heifers were divided randomly into two groups; MGA-treated (n = 8) or control (CON; n = 9). Puberty was determined by monitoring circulating concentrations of progesterone and ovarian morphology during a 14-day period following MGA withdrawal. LH secretory patterns were assessed upon initiation of MGA (Day 0), during MGA (Day 7), and 1 day after withdrawal of MGA (Day 9). All MGA-treated heifers, versus four CON heifers, exhibited corpora lutea and luteal phase concentrations of progesterone within 10 days after treatment (p = 0.01). Mean LH and LH pulse frequency increased (p = 0.005 and 0.0001, respectively) between Days 0 and 9 in MGA-treated heifers. In CON heifers, mean LH concentrations and pulse frequencies did not change. During the same period, diameter of the largest follicle increased in MGA-treated animals (p = 0.003) but did not change in the CON heifers. On the basis of these results, we suggest that MGA withdrawal enhances onset of puberty by stimulating pulsatile LH secretion that accelerates follicle growth to the preovulatory stage.

Animals↗
PubMed1997

Estrus synchronization with an oral progestogen prior to superovulation of postpartum beef cows.

Ovarian follicular dynamics and steroid secretion patterns were monitored in postpartum beef cows that were synchronized for estrus with melengestrol acetate (MGA) or prostaglandin F(2alpha) (PGF) prior to superovulation. Twenty-four muhiparous Angus cows were stratified by number of days postpartum to an MGA or PGF treatment prior to superovulation. Cows in the MGA group were fed 0.5 mg MGA/d for 14 d in a grain carrier. Superstitnulatory treatments began 14 d after withdrawal of MGA from feed or 11 d after administering a single injection of 500 microg cloprostenol (PGF). Supersthnulatory treatments (FSH) were administered twice daily in decreasing doses (7.5, 5, 5, 2.5 mg) over 4 d. Sixty and 72 h after initiating the superstimulatory treatments, all cows were treated with 750 microg and 500 microg PGF, respectively Cows were inseminated at 0, 12, and 24 h from the onset of standing estrus with semen from 2 proven sires. Cows within treatment were inseminated with 1, 2 and 1 (single) or 2, 4 and 2 units (double) of semen at the designated insemination times. Blood sampling and transrectal ultrasonography of ovaries were performed daily beginning 2 d prior to the initiation of FSH treatment and were continued through embryo recovery. Ovaries were examined daily to determine the number and size of follicles. Plasma samples were analyzed for progesterone and estradiol. Follicles were counted and categorized based on a 5 to 9 mm range or >/= 10 mm. At the end of superovulatory treatment there were more (P </= 0.01) follicles >/= 10 mm among cows that were estrus synchronized with MGA (75 +/- 1.2) than with PGF (3.9 +/- 1.2) These differences were reflected in higher (P </= 0.05) subsequent concentrations of plasma progesterone, suggestive of differences in ovulation rate between treatments (MGA = 8.5 ng/ml; PGF = 5.6 ng/ml). There were no significant differences between treatments in concentrations of estradiol, total number of ova (MGA = 11; PGF = 9), fertilized embryos (MGA = 9; PGF = 7), or transferable embryos recovered (MGA = 8; PGF = 6) Furthermore, double insemination offered no significant improvement in the number of recovered fertilized ova. These data identify differences in follicular and endocrine response when cows were estrus synchronized with MGA versus PGF prior to superovulation.

Journal Article↗
PubMed1996

Change in morphology of corpora lutea, central luteal cavities and steroid secretion patterns of postpartum suckled beef cows after melengestrol acetate with or without prostaglandin F2alpha.

Change in morphology of the corpus luteum (CL) and patterns of progesterone and estradiol secretion after treatment with melengestrol acetate (MGA) were monitored in postpartum beef cows. Twenty Angus cows were randomly assigned to MGA or MGA + prostaglandin F(2alpha) (PGF) treatments. All cows were fed 0.5 mg of MGA per cow per day for 14 d. The MGA-treated cows (n = 10) were allowed to return to estrus spontaneously at the second estrus after withdrawal of MGA from the feed. The MGA + PGF-treated cows (n = 10) received an injection containing 25 mg of PGF(2alpha) 17 d after the last feeding of MGA. Cycle 1 was defined as the first luteal phase after MGA feeding and Cycle 2 represented the subsequent cycle or luteal phase after PGF. Blood sampling and transrectal ultrasonography of the ovaries was done daily through the completion of 2 estrous cycles upon removal of MGA from the feed. Blood samples were analyzed for plasma progesterone and estradiol concentrations. Area of CL and fluid-filled cavities within each CL were determined by ultrasonography. Concentrations of progesterone and area of CL were similar between cycles and treatments. Estradiol concentrations were higher (P < 0.05) in Cycle 2 than in Cycle 1. Fluid-filled cavities were larger (P < 0.001) in Cycle 1 than in Cycle 2 for both mid-luteal (Days 5 to 9) and late-luteal (Days 10 to 14) phases. Multiple CL (2 or more during 1 cycle) were observed in 5 cows. Progesterone concentrations and total area of luteal tissue did not change with respect to treatment or cycle, but CL morphology was altered in the first cycle after MGA treatment. Of the 19 cows that ovulated after withdrawal of MGA, 3 experienced a short luteal phase. These data characterize changes that occur among cows that are fed melengestrol acetate during the postpartum period and enhance observations from prior studies regarding MGA use.

Journal Article↗
PubMed1996

Thawing and processing of cryopreserved bovine spermatozoa at various temperatures and their effects on sperm viability, osmotic shock and sperm membrane functional integrity.

The objective of this study was to evaluate the effects of thawing and processing temperatures on post-thaw sperm viability, occurrence of osmotic shock and sperm membrane functional status. The occurrence of osmotic shock, characterized by increased spermatozoa with coiled tails, eventually results in reduced sperm viability and sperm membrane integrity. The effects of different thawing temperatures were assessed by thawing frozen specimens at 37, 21 or 5 degrees C for 1 to 2-min, followed by processing at these temperatures. A subset of frozen specimens were thawed at 37 degrees C for 10 to 15-sec and transferred to a water bath at 21 or 5 degrees C for 1 to 2-min to complete thawing, followed by processing at these temperatures. Sperm processing (washing) consisted of dilution, centrifugation and resuspension to remove glycerol from the medium and to gradually return the spermatozoa to isotonic conditions. Post-thawed specimens (0.5 mL) were slowly diluted 1:1 (v/v) at a rate of 0.1 mL/min, centrifuged, and resuspended to 0.5 mL (37 degrees C). Diluted specimens were equilibrated for 1 to 2-min after dilution and for 5-min after resuspension. The specimens were then incubated for 2-h (37 degrees C) and assessed at 60-min intervals for the percentage of motility, for progressive motility (Grades 0 to 4), for the percentage of spermatozoa with coiled tails, and for the percentage of swollen spermatozoa. The percentage of swollen spermatozoa (measurement of sperm membrane integrity) was assessed by exposing spermatozoa to a modified hypoosmotic swelling (HOS) test. The results obtained seem to indicate that physiological thawing and processing temperatures (37 degrees C) are required to maintain sperm motility. However, thawing and processing at lower temperatures (< 37 degrees C) seems to prevent the occurrence of osmotic shock and to maintain sperm membrane functional integrity. In this study, thawing at 37 degrees C (10 to 15-sec) and transfer to a water bath at 21 degrees C (1-min) to complete thawing, followed by processing at 21 degrees C, yielded better results in terms of increased sperm viability, reduced occurrence of osmotic shock and higher reactivity to the HOS test.

Journal Article↗
PubMed1996

Expandable versus conventional esophageal prostheses: easier insertion may not preclude subsequent stent-related problems.

BACKGROUND: Although expandable esophageal endoprostheses may be easier to insert and are associated with fewer procedure-related perforations, data comparing clinical results with these stents to those obtained with conventional prostheses are sparse. METHODS: We reviewed the records of all patients undergoing esophageal stent placement at our institution between October 1983 and July 1995 to define relative risks, clinical results, and need for reintervention prior to death, contrasting conventional to a variety of expandable esophageal endoprostheses. RESULTS: Over the period of review, 47 patients had conventional prostheses (CP) and 38 had expandable prostheses (EP) placed. Fifteen of 44 patients with CP and 14 of 38 with EP for malignancy also had esophago-airway fistulas. Insertion complications, prestent and poststent dysphagia scores, and complete fistula occlusion rates were comparable. Subacute complications were higher in the patients receiving EP (80%) than in those receiving CP (60%), possibly related to the prospective accumulation of data in patients receiving EP. Survival data were virtually identical and approximated 3 months for either group. CONCLUSIONS: Although both CP and EP improve dysphagia and occlude tracheoesophageal fistulae, patients ill enough to require a prosthesis do poorly regardless of prosthesis design. Moreover, although EP may be easier to insert than CP, stent- and patient-related problems persist and may require additional intervention.

Aged↗
PubMed1995

Endoscopic approach to pancreas divisum.

Pancreas divisum has been claimed to be a harmless congenital variant or to occasionally cause acute relapsing pancreatitis (ARP), chronic pancreatitis (CP), or a chronic abdominal pain (CAP) syndrome. Both surgical and endoscopic approaches to accessory papilla decompression have been promulgated and widely disparate results reported in the literature. We retrospectively reviewed a five-year experience with dorsal pancreatic duct decompression at our institution utilizing a variety of endotherapeutic techniques. Data collected included procedural complications; patient interpretation of pre- and posttherapy pain, frequency, and intensity graded on an analog pain scale; frequency of hospitalization; and patient perception of "global" improvement to endotherapy. At a mean follow-up of 20 months, there was a statistically significant decrease in pancreatitis incidence in 15 patients with ARP (P = 0.016) and 19 patients with CP (P = 0.025). The frequency and intensity of chronic pain was also significantly improved (P < 0.001) in the latter group. In contrast, only one of five patients with CAP and normal dorsal pancreatography and secretin tests experienced global improvement, and there was no improvement utilizing an analog pain scale (P = 0.262) in the group as a whole. There was a 20% incidence of mild procedure or subsequent stent-related pancreatitis and an 11.5% accessory papilla restenosis rate. It is concluded that a subset of carefully selected patients with pancreas divisum may respond to endotherapy but that long-term follow-up will be required to define its ultimate place in the management of symptomatic patients with this anomaly.

Abdominal Pain↗
PubMed1995

Survey for internal parasites in cattle in Kentucky (1993).

Fecal samples were examined between 17 September and 1 November 1993 from 1765 cattle (one bull, 533 cows, 474 heifers, 22 steers, and 735 calves) on pasture on 15 farms in 11 counties in Kentucky for eggs or larvae of internal parasites. All of the cattle were beef-type except for 22 which were dairy-type. In fecal samples from the bull, cows, heifers, steers, and calves, the types of helminth eggs present were trichostrongyles (excluding Nematodirus) in 0%, 25%, 31%, 86%, and 93%, Nematodirus in 0%, 0%, < 1%, 0%, and 34%, Strongyloides in 0%, 0%, < 1%, 0%, and 7%, Trichuris in 0%, 0%, 0%, 0%, and 2%, Capillaria in 0%, 0%, 0%, 0%, and < 1%, and Moniezia in 0%, 1%, 8%, 5%, and 21%, respectively. Dictyocaulus viviparus larvae were present in feces of calves (7%) on one farm and heifers (< 1%) on another farm.

Animals↗
PubMed1995

Iatrogenic achalasia. A case series.

Between 1984 and 1992, 14 cases of "secondary" achalasia were diagnosed at our institution, five due to malignancy and nine as a result of esophageal or paraesophageal surgery. Preoperative manometry had excluded preexistent achalasia in eight of nine of the latter patients. Dysphagia developed immediately postoperatively in all. Esophagram and subsequent manometry were consistent with achalasia. All failed conventional dilation sessions and eight of nine underwent pneumatic dilation: Five were cured by this alone, two required surgery (one for iatrogenic perforation), and one was lost to follow-up. This achalasia-like picture appears to be the result of a tight antireflux repair that impairs the ability of the lower esophageal sphincter to completely relax, creating a functional obstruction with proximal dilation and stasis. Such secondary achalasia appears to be a distinct clinical entity and was more common than that associated with neoplasia in our institution. Therapeutically, pneumatic dilation was required and probably causes partial disruption of a tight surgical repair.

Adenocarcinoma↗
PubMed1995

Esophageal dilation can be done safely using selective fluoroscopy and single dilating sessions.

Maxims for safe esophageal dilation have included recommendations to use fluoroscopy in all instances and to limit dilation sessions to 2-mm increments. We reviewed a 34-month experience of all esophageal dilations undertaken at a large multispecialty clinic to define adherence to these recommendations and to delineate whether deviation was associated with significant complications. Four hundred thirty-two patients underwent 716 courses of esophageal dilation during this time, 92% of whom had benign disease. Eighty-nine percent of patients were dilated with polyvinyl dilators (Savary/American) and only 8% of these patients required fluoroscopic monitoring for the bougienage. Seventy-eight percent of the dilating sessions for patients without achalasia were undertaken using either a single large dilator (> or = 45 Fr) or employed incremental dilator sizes > 2 mm (6 Fr) in a single session. There was a single perforation in 662 nonachalasia dilations and this was a consequence of attempted placement of an esophageal endoprosthesis. We conclude that use of guide wire technology and newer dilating techniques do away with the need for routine fluoroscopic control. Moreover, single large dilators or dilator increments > 2 mm may be safely used, contingent on endoscopic stricture assessment.

Dilatation↗
PubMed1995

A 'big five' scoring system for the item pool of the adjective check list.

The item pool of the Adjective Check List (ACL; Gough & Heilbrun, 1980) is widely used as a means of capturing the personal characteristics associated with various target groups (e.g., women vs. men, young adults vs. old adults). The purpose of this research was to develop a system for scoring the ACL items in terms of the five-factor model of personality. In Study 1, five groups of introductory psychology students served as judges, with each group of approximately 100 persons rating the 300 ACL items for one of the five factors. The ratings of each factor were highly reliable. When corrected for favorability, the intercorrelations among the five factors were quite low, as expected, except for the positive correlation of Openness and Extraversion. Good convergence was found between our ratings and the indicative and counterindicative items identified by John's (1989) graduate student judges. In Study 2, convergent validity was demonstrated between the five-factor scores obtained from self-descriptive ACLs and corresponding factor scores obtained from Costa and McCrae's NEO-PI-R and NEO-FFI instruments (Costa & McCrae, 1992). Data from earlier cross-cultural studies of gender and age stereotypes were rescored using the new ACL-FF system to illustrate its potential utility as a research tool.

Journal Article↗
PubMed1995

Improved synchrony, conception rate, and fecundity in postpartum suckled beef cows fed melengestrol acetate prior to prostaglandin F2 alpha.

Occurrence of estrus, conception rate, and fecundity were compared between postpartum suckled beef cows fed or not fed melengestrol acetate (MGA) before synchronizing estrus with prostaglandin F2 alpha (PG). One hundred thirty-three purebred Angus cows were stratified by age and days postpartum to one of two treatments. All cows received an injection containing 25 mg of PG; however, one group (MGA+PG) was fed .5 mg of MGA.cow-1.d-1 for 14 d then received PG 17 d after the last feeding of MGA. The other group (PG) received only PG. Cows in both treatments that failed to exhibit estrus within 6 d after PG received a second injection of PG 11 d after the first injection was administered. Cows were checked for estrus from the first PG injection until 6 d after the second PG injection. Cows were inseminated with semen from a 3/4 Brahman bull 12 h after observed estrus. Cows were exposed to Angus bulls after the AI period. Conception date was determined by palpation per rectum and verified by calving date and calf phenotype. Differences in response variables were analyzed by chi-square. A greater proportion of cows (P < .04) that were pretreated with MGA exhibited estrus after the first injection of PG (76%) than of cows that received only PG (60%). Total response did not differ between treatments after both injections of PG. Conception rate among cows that received a first service was higher (P < .007) for the MGA+PG (88%) group than for the PG (67%) group, although the total number of cows that received a first service was not different between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1994

Interactive effects of K+, acidosis, and catecholamines on isolated rabbit heart: implications for exercise.

Intense exercise can double arterial K+ concentration, decrease pH by 0.4 units, and increase catecholamines 15-fold. Any one of these changes may be cardiotoxic in a subject at rest, yet these changes are well tolerated in exercise. We tested the interactive effects of extracellular K+ concentration ([K+]o), metabolic acidosis (pH 7.0), and raised catecholamines in the isolated working rabbit heart when they were changed with similar kinetics and concentrations to those seen in exercise. Raised [K+]o (8 and 12 mM) significantly decreased aortic flow (AF) by 23 and 76%, respectively (P < 0.01). Acidosis decreased AF by 19% (P < 0.05) and by 38% in combination with 8 mM [K+]o (P < 0.05), making their combined effect additive. Either epinephrine (80 nM), norepinephrine (80 nM) or extracellular Ca2+ concentration (5 mM) offset the negative effects of 8 and 12 mM [K+]o on AF. Norepinephrine also improved AF in 8 mM [K+]o with acidosis. Thus, there may be a beneficial interaction among changes in K+, catecholamines, and acidosis during exercise such that each could offset the others' potentially harmful effects.

Acidosis↗
PubMed1994

Prokinetic agents in postgastrectomy patients.

Postgastrectomy syndromes are uncommon but, unfortunately, frustrating for both patient and physician, because treatment with prokinetic agents is often of limited benefit. This article examines the evidence for efficacy of available prokinetic drugs in the management of these difficult disorders.

Bethanechol↗