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Biomedical subjects

M L Patton

Publications and source records attributed to M L Patton.

At least 19 recordsLinked to original sources
PubMed2005

Glucocorticoids of bison bulls in relation to social status.

A primary response to stress is an increase in circulating adrenal glucocorticoids (GC) such as cortisol. Two hypotheses propose differential stress responses to agonistic and aggressive interactions in social groups. If subordinate animals are subjected to social and psychological stressors leading to chronic GC elevation, the 'stress of subordination' hypothesis predicts that GCs will be higher in subordinates than dominants. Alternatively, if dominant animals are subject to physiological stressors (e.g., fight at higher rates than subordinates) or hierarchies are unstable, the 'stress of domination' hypothesis predicts higher GCs in dominant individuals. Both models predict that GC levels will peak during the breeding season. We tested these predictions in bison bulls (Bison bison) using fecal steroid analysis to characterize GC concentration and behavioral observations to determine dominance rank, copulatory success, and tending status of bulls. Fecal samples were collected during 2003 from adult bison bulls during pre-rut (June), rut (July-August), and post-rut (September). Matched sample data indicated that mean GC levels (ng/g feces) of bulls strongly peaked during the 4-week rut, doubling from pre-rut to rut and then declining again during post-rut. High ranked dominant bulls maintained higher GC levels than lower ranked subordinate bulls. Dominance rank was positively correlated with copulatory success and age, and dominant bulls were more likely to tend (guard) cows as they approached estrus. There was a positive correlation between GC level and copulatory success, with prime-aged bulls (> or =7 years) obtaining the most copulations. GC levels were positively correlated with bull androgen levels determined in a previous study. These results support the 'stress of domination' hypothesis, indicating that dominant bison bulls pay a significant physiological price for high social status and the opportunity to mate.

Aggression↗
PubMed2004

Fecal androgens of bison bulls during the rut.

The influence of sex hormones is a key proximate factor underlying male reproductive behavior in mammals. Effective conservation policies for the remaining purebred plains bison (Bison bison bison) herds require knowledge of the physiology underlying bison reproductive biology. We used fecal steroid analysis to characterize androgen levels in adult bison bulls before, during, and after the rut, and to examine androgen levels of bulls differing in reproductive status, age, and mating success. Fieldwork was carried out at the Fort Niobrara National Wildlife Refuge in north-central Nebraska. All adult bison in the herd were individually known by unique brands. Fecal samples were collected during 2003 from bulls during pre-rut (June), rut (July-August), and post-rut (September), and behavioral observations focused on reproductive status and mating success during the rut. Matched sample data indicated that androgen levels (ng/g feces) of bulls peaked during the rut, doubling from pre-rut to rut and then declining by 75% during post-rut. Dominant bulls that tended (guarded) cows maintained higher androgen levels than bulls that were not tending. There was a positive correlation between bull age (associated with mating success) and androgens, with higher androgen levels in prime-aged bulls compared with younger bulls. Nonetheless, there was no correlation between mating success (measured by number of copulations observed) and androgen level. This suggests that while androgens may provide the proximate motivation to compete for matings, other factors determine the mating success of bison bulls.

Age Factors↗
PubMed2001

Ultrasonographic characterization of ovarian events and fetal gestational parameters in two southern black rhinoceros (Diceros bicornis minor) and correlation to fecal progesterone.

A tremendous potential exists for the application of transrectal ultrasonography as a tool to enhance the captive management of endangered species. Reproductive study of two southern black rhinoceros (Diceros bicornis minor) females was performed daily to every other day for a approximately 60 day period to document ovarian changes, and three times weekly in early pregnancy to once monthly in late pregnancy in order to characterize changes in fetal parameters throughout gestation. All ovarian and fetal anatomical structures were measured in millimeters. The mean (+/- SD) length of the estrous cycle or interovulatory period was 26 +/- 1.4 days (n=2 cycles). Follicular growth rate of a dominant follicle was approximately 3 mm/day once the follicle reached 35 mm in diameter. Ovulation was observed to occur at a mean (+/- SD) follicular diameter of 49.5 +/- 2.6 mm (n=4) and within 48 to 72 h after observed estrus (n=2). Large ovarian structures [mean (+/- SD) diameter of 71.7 +/- 2.9 mm; n=3], considered analogous to equine anovulatory hemorrhagic follicles, were observed to form in the winter months and suggest seasonal periods of reduced fertility. Fecal progesterone assays confirmed ultrasonographic events. Although preliminary, the results of fetal sexing are presented and compared to the horse. Our data indicate that fetal eye or fetal foot diameter measurements can be used to accurately predict gestational age from about 2 months to term, providing useful information to managers of both captive and wild rhino populations. The ability to identify and quickly release animals in late term pregnancy in the wild and thereby reduce-abortions and neonatal mortalities in holding bomas is one potential practical conservation benefit of the fetal age predictive models.

Animals↗
PubMed2001

Identification of a series of C(21)O(2) pregnanes from fecal extracts of a pregnant black rhinoceros (Diceros bicornis minor).

Fecal extracts from a pregnant black rhinoceros, Diceros bicornis, were analyzed by radioimmunoassay, HPLC, and by GC-mass spectrometry. From 40 g of dried feces a total of 33 pregnanes in the C(21)O(2) series, including a number of novel 17 alpha epimers were identified. No progesterone was recovered. The principal progesterone metabolite by mass was 5 alpha-pregnan-3 beta,20 alpha-diol (44.5%), which did not cross react with the antibody used in our RIA. The antibody recognized progesterone and pregnanes with 20-one configuration, which when combined made up less than 15% of the total C(21)O(2) steroid mass. Of the 33 pregnanes in the C(21)O(2) series identified, 81%, by mass, were in the 5 alpha-configuration. These results are compared with studies in other rhinoceros species (Asian and Sumatran) in which pregnanes in the 5 beta-configuration are the major fecal metabolites, and the white rhinoceros in which pregnanes in the 5 alpha-configuration are the dominant form.

Animals↗
PubMed2000

Trichosporon beigelii infection: experience in a regional burn center.

Trichosporon beigelii is a fungus once thought to cause only superficial infections, but recently has been increasingly identified as an opportunistic systemic pathogen in immunocompromised patients. There have been very limited reports of this organism in the burn patient population. We describe the first report of pharmacological management of invasive T. beigelii with a combination of amphotericin B and high dose fluconazole in a burn patient. Antifungal susceptibility testing of T. beigelii determined a change in minimum inhibitory concentrations (MICs) of amphotericin B and a consistent resistance pattern with the use of flucytosine. This paper will review our experience with T. beigelii fungus in a regional burn treatment center and review the literature on other experiences in the burn population.

Adult↗
PubMed2000

Successful contraception in a herd of Chinese goral (Nemorhaedus goral arnouxianus) with melengestrol acetate.

Thirteen Chinese goral (Nemorhaedus goral arnouxianus) (five males and eight females) were each given 0.8 mg of melengestrol acetate orally in pelleted food for 224 days. The previous breeding season, six of the eight females calved (two were immature). No calf was born during the treatment season. The season after treatment, six females calved (one was immature prior to treatment). Two females were moved to other institutions, and the status of these is unknown. On the basis of this information, melengestrol acetate in feed was successful in preventing conception and was reversible. This treatment did not prevent the siring of offspring the following year and did not prevent a female that was subadult prior to the treatment from calving.

Administration, Oral↗
PubMed1999

Intravenous immunoglobulin as adjunctive treatment for streptococcal toxic shock syndrome associated with necrotizing fasciitis: case report and review.

Streptococcal toxic shock syndrome (STSS) is caused by infection with a toxicogenic strain of Streptococcus pyogenes. Clinical manifestations may be those of a mild illness, characterized by malaise, fever, and muscle pain, to severe sepsis and multisystem organ failure. The syndrome may be associated with several invasive infections including necrotizing fasciitis. Treatment is primarily surgical debridement of infected tissue with supportive care, antibiotics, and hemodynamic monitoring. Intravenous immunoglobulin (IVIG) is reported to have beneficial effects in the management of STSS associated with necrotizing fasciitis. The agent was successful in conjunction with surgical excision and antibiotics in a patient with necrotizing fasciitis, toxic shock, and multisystem organ failure. On the basis of this experience and a thorough literature review, we concur that IVIG may be a useful adjunct in the treatment of STSS associated with necrotizing fasciitis.

Adolescent↗
PubMed1998

Successful utilization of ECMO to treat an adult burn patient with ARDS.

We present an interesting case of the first adult reported in the United States to suffer from thermal burns, adult respiratory distress syndrome (ARDS) and to be treated with extracorporeal membrane oxygenation (ECMO) who survived. Our patient is a 26 year old male who sustained thermal burns (12% TBSA) to his face and anterior trunk and broncoscopically demonstrable inhalation injury. He was transported to our regional burn center for burn wound care and ventilatory support. The patient was treated with silver sulfadiazine 1% to his wounds which healed per primam. Because of low oxygen saturation he required increasing FIO2. The following parameters: FIO2= 1, PEEP = 17, minute ventilation of 15.1 1, peak airway pressure of 45 and mean of 27, along with chest X-rays corroborated the severity of ARDS. The patient failed volume control ventilation. A trial of pressure ventilation was attempted but the patient only reached O2 saturation in the low 80s. At this point, the decision was made to transfer the patient to a hospital capable of ECMO treatment. The patient was subsequently treated with veno venous ECMO. Six weeks later the patient was discharged from the hospital off all ventilatory support.

Adult↗
PubMed1997

Concomitant laparoscopic cholecystectomy and splenectomy for surgical management of hereditary spherocytosis.

Laparoscopic splenectomy is rapidly becoming a common treatment modality in the surgical management of hematological processes involving the spleen. Hereditary spherocytosis is the most common red blood cell membrane disorder, and its diagnosis is often associated with hemolytic crisis and premature cholelithiasis. This condition has not been successfully treated laparoscopically until recently, and to our knowledge, the technique of concomitant laparoscopic splenectomy and cholecystectomy described here is the first reported in U.S. literature. Our patients, a 16-year-old 5-foot 3-inch-tall 90 pound emaciated albino, presented with cholelithiasis, splenomegaly, and anemia. Because of persistent anemia and gastrointestinal symptoms, the patient underwent laparoscopic cholecystectomy and splenectomy. The cholecystectomy was performed in a standard laparoscopic fashion. An additional 12-mm trocar was utilized for takedown of the spleen. The umbilical incision was extended to 4.5 cm, and the spleen was extracted manually. Total operative time was 12 hours. Examination demonstrated a 15 x 10 x 5-cm spleen, which weighed 350 grams. The gallbladder microscopically showed cholecystitis and had several stones. In conclusion, we present a combined laparoscopic cholecystectomy and splenectomy for hereditary spherocytosis associated with splenomegaly, cholelithiasis, and cholecystitis.

Adolescent↗
PubMed1995

Barium and fecal impaction: an unusual case of bilateral hydronephrosis.

We present an interesting case report of the second adult female reported to suffer from bilateral ureteral hydronephrosis, secondary to a fecal impaction, and the first caused by complications from residual barium. This elderly patient suffers from many associated neurologic, bowel, and urinary tract problems; this case report demonstrates their close proximal relationship. Through ureteral stent placement and manual disimpaction of the barium fecaloma, the patient was able to recover her normal renal and bowel functions. Aided by the use of excellent figures, it is our intent to inform physicians that they should consider fecal impaction as a cause for bilateral ureteral hydronephrosis in predisposed patients, and also the necessity of purging the GI tract of residual barium following radiologic studies.

Aged↗
PubMed1994

Use of percutaneous endoscopic gastrostomy tubes in burn patients.

Alimentation and decompression are imperative to the successful management of the severely burned patient. Utilization of percutaneous endoscopic gastrostomy (PEG) tubes for these purposes has become a proven effective procedure in non-burned patients with few major complications. We retrospectively reviewed placement of PEG tubes in 31 burn patients, some of whom had been admitted with additional diagnoses such as inhalation injury and/or dysphagia. In 90% of our burn patients, the use of PEG tubes was without complication. The placement of PEG tubes through burn wound areas or donor sites added no increase in wound complications. In summary, there was no mortality referable to the use of PEG tubes, there were no major operative or wound complications, and feedings were tolerated well. This study reports on the use of PEG tubes in a regional Burn Treatment Center. It shows that PEG tubes offer safe and effective alimentation and decompression in the management of burned patients.

Adolescent↗
PubMed1993

An improved technique for needle localized biopsy of occult lesions of the breast.

The current retrospective study reports the results of the 98 outpatient procedures using a modified version of needle localized excisional biopsies of occult lesions of the breast at a community hospital. Intraoperative fluoroscopy is used to direct a second needle placement along the dissection tract to localize more accurately the intraglandular lesion. The medical records of 88 patients who underwent this procedure between 1989 and 1991 were reviewed. A detailed description of the procedure used as well as clinical data from roentgenographic, histologic and operative reports are given. Benign histologic findings were reported in 80.6 percent of the instances, with fibrocystic disease accounting for most (66 of 79) of the benign diagnoses. Primary malignancy was found in 18 biopsies, with noninfiltrating ductal carcinoma being the most prevalent (n = 8). Infiltrating ductal carcinoma was found six times, infiltrating lobular carcinoma was found three times and a combination of noninfiltrating ductal and noninfiltrating lobular carcinoma was found once. Metastasis to axillary lymph nodes was found twice. One lesion of the breast was large cell lymphoma. Mass lesions accounted for 46 of the 98 lesions and calcifications accounted for the remaining 52. Thirteen of the 18 primary lesions that proved to be malignant presented as calcifications, whereas five presented as a mass. Infiltrating carcinoma, however, was more likely to be associated with mass lesions than with calcifications--all five malignant mass lesions were infiltrating, whereas of the 13 lesions with calcifications, four were infiltrating. Failure to confirm the removal of the lesion roentgenographically occurred once, but there were no other complications to this technique. Additionally, a circumareolar incision was used in 64.7 percent of the procedures and 76.5 percent of the procedures were done using local anesthesia and intravenous sedation. We conclude that the technique introduced herein is a simple, highly reliable means to localize accurately nonpalpable lesions of the breast using a combination of fluoroscopy and needle localization that allows a better cosmetic result.

Adenofibroma↗
PubMed1993

Diminishing blood loss during operation for burns.

The current placebo-controlled, randomized clinical trial was done to determine the effect of preoperative 1-desamino-8-D-arginine vasopressin (DDAVP) infusion on blood loss in patients undergoing burn débridement and grafting, a patient population in which extreme blood loss is a frequent occurrence. Eleven patients undergoing 22 surgical procedures completed the study protocol--mean age was 33 years (range of 12 to 70 years), mean burn size was 53 percent body surface area (BSA) (range of 17 to 92 percent) and mean area débrided and grafted was 3,935 centimeters squared (range of 848 to 8,134) or 21.1 percent (range of 4.0 to 43.5 percent) BSA. The treatment group received 0.3 microliter per kilogram DDAVP infused during 15 to 30 minutes within one hour of anesthetic induction. The control group received placebo in a similar manner. Standard hemostatic maneuvers were used in all patients. Blood loss was calculated based on Warden's formula. No significant hemodynamic consequences or changes in routine coagulation profiles were noted in either group. No significant difference was found between the control and treatment groups in the volume of blood lost per percent BSA débrided and grafted (145.9 +/- 109.7 versus 130.2 +/- 61.7, respectively) or the volume lost per unit area débrided and grafted (0.75 +/- 0.54 versus 0.74 +/- 0.41, respectively). Based on these data, we cannot conclude that preoperative DDAVP infusion reduces blood loss in patients undergoing débridement and grafting of burn wounds.

Adolescent↗
PubMed1992

Can general surgeons perform colonoscopy safely?

The purpose of the current study was to review the safety of colonoscopy performed by nonfellowship-trained general surgeons. To address this issue, we reviewed more than 1,000 consecutive diagnostic and therapeutic colonoscopies and recorded the complications. This was a multi-institutional study involving seven general surgeons, none of whom had had formal fellowship endoscopic training. Perforation was confirmed by laparotomy, bleeding was defined as that requiring hospitalization and/or transfusion, and cardiopulmonary arrest was self-explanatory. There was one perforation in the diagnostic group and none in the therapeutic group, for a rate of 0.10% overall and 0.12% in diagnostic colonoscopy. There were no instances of bleeding or cardiac arrest. This complication rate of 1 per 1,025 colonoscopic procedures by general surgeons compares favorably with that previously reported by other specialties (p less than 0.001). We conclude that postgraduate endoscopy fellowship is not necessary for general surgeons to become safe colonoscopists.

Clinical Competence↗
PubMed1992

The response of statocyst receptors of the lobster, Homarus americanus, to movements of statolith hairs.

1. While recording from the statocyst nerve of Homarus americanus, we deflected the statolith hairs from the "rest" position they assumed after the lith was removed. 2. Each of the smaller statocyst hairs apparently drove three sensory receptors; all receptors were sensitive to hair position, hair movement velocity, and hair movement direction. 3. Two of the receptors, types A and C, only responded when the hair was lifted up and away from rest; the third, type B, only responded vigorously when a hair was moved back toward rest from such a deflexion. 4. Type A and B receptors were phasic-tonic; type C receptors were phasic.

Animals↗
PubMed1991

Impairment of follicular development by intra-ovarian infusion of gonadotrophin-releasing hormone antiserum in prepubertal pigs.

Antiserum against gonadotrophin-releasing hormone (GnRH) was infused into one ovary in 4 prepubertal gilts and control porcine serum was infused into one ovary in 4 other gilts. Ovaries were infused for 156 h, after which infused and non-infused ovaries were removed surgically and processed for histology. Infusion of GnRH antibodies did not alter (P greater than 0.10) concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH) or oestradiol-17 beta, and GnRH titres in peripheral circulation were low, averaging 1:15. Weights of ovaries not infused were similar (P greater than 0.10) between treatment groups. There were fewer (P less than 0.05) follicles greater than 0.5 mm in diameter in the ovaries infused with GnRH antiserum than in the others, but there were no differences (P greater than 0.10) between treatment groups in the number of follicles less than 0.5 mm in diameter. Infusion of GnRH antibodies increased (P less than 0.05) the incidence of atresia in follicles with greater than 4 layers of granulosa cells compared with the other treatment groups. These results provide evidence that a peptide binding to the GnRH antibodies is involved directly in ovarian follicular development.

Animals↗
PubMed1988

Hydrofluoric acid-induced hypocalcemia.

Among patients exposed to hydrofluoric acid the potentially lethal effect of calcium depletion induced by binding with fluoride ion has not been well reported. Three patients exposed to hydrofluoric acid had acute fluoride poisoning with serum calcium levels equal to or below 4.1 mgm/dl. Treatment included administration of large amounts of calcium, both intravenously and by subsechar injection, to replenish the biologically active calcium and to bind fluoride. This report describes successful treatment of two survivors, apparently the first two, of severe hypocalcemia caused by hydrofluoric acid.

Adult↗