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Biomedical subjects

D P Ryan

Publications and source records attributed to D P Ryan.

At least 19 recordsLinked to original sources
PubMed1992

Treatment of acute pulmonary failure with extracorporeal support: 100% survival in a pediatric population.

Since February 1990, five children, aged 10 days to 6.5 years, were treated with extracorporeal lung support at our hospital for acute, unrelenting pulmonary failure. Two had viral pneumonia: one with respiratory syncytial virus (RSV) bronchiolitis, and one with herpes simplex virus pneumonia, encephalitis, and disseminated intravascular coagulation. One presented with a febrile illness followed by a pulmonary hemorrhage. Two patients had adult respiratory distress syndrome (ARDS) complicating severe systemic illnesses, toxic epidermal necrolysis in one and cat scratch disease with encephalitis in the other. All children had diffuse parenchymal lung disease by chest x-ray. On maximum medical management all patients were developing carbon dioxide retention and progressive hypoxemia, exceeding previously established NIH study criteria for extracorporeal treatment. Three children (10 days, 2 months, 13 months) were placed on venoarterial support and two children (20 months and 6.5 years) were placed on venovenous extracorporeal support (ECCO2R). Three of the five had open lung biopsies performed, which showed findings consistent with a moderate to severe cellular phase of ARDS. No viral inclusions were found in the patient with RSV infection. One hundred percent immediate survival was achieved in this patient population. Average duration of support was 330 hours (range, 89 to 840). Following completion of extracorporeal support, all children were successfully weaned from the ventilator with an average time to extubation of 23.2 days (range, 2 to 58 days). One child died of congestive heart failure following palliative surgery for a complex noncyanotic congenital cardiac lesion 35 days after successfully weaning from extracorporeal support for an acute febrile illness and pulmonary hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1992

Ectopic class II major histocompatibility antigens in Hirschsprung's disease and neuronal intestinal dysplasia.

Although the etiology of Hirschsprung's disease and neuronal intestinal dysplasia remains obscure, both have histological abnormalities involving ganglion cells and neuronal elements. Searching for a common pathway that may inhibit normal maturation of neurogenic precursors, we examined the possible role of an immune mechanism in the maldevelopment of the enteric neural network. Six patients with Hirschsprung's disease were studied by comparing biopsy specimens from diseased colon with ones taken from proximal ganglionic colon in the same patients. These were similarly compared with colonic biopsy specimens from patients studied with chronic constipation or bowel removed at the time of operation for other disorders. Biopsies were taken from four other patients with neuronal intestinal dysplasia. Each was examined by hematoxylin & eosin staining, acetylcholinesterase histochemistry, and immunohistochemistry of major histocompatibility complex (MHC) class I and class II antigens. All rectal samples from Hirschsprung's disease patients exhibited elevated acetylcholinesterase histochemistry and absent ganglia to confirm the diagnosis. These findings were correlated with marked elevation of class II MHC in the aganglionic area, whereas the proximal normal ganglionic segments showed no elevation. Rectal biopsy specimens from patients with chronic constipation exhibited no such elevation. A similar elevation of class II MHC was detected in the mucosa and submucosa of all four patients with the rare neuronal intestinal dysplasia disorder whose diagnosis was confirmed by giant ganglia in Auerbach's plexuses, aberrant Meissner's ganglia in the lamina propria mucosa, and giant neurofibrils in the mucosa and submucosa. The correlation of elevated class II MHC in these two neuronal dysfunction disorders may indicate an underlying autoimmune mechanism as is seen in thyroiditis and insulin dependent diabetes mellitus.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1992

Effect of heat-stress on bovine embryo development in vitro.

Chronic elevation of uterine temperature has long been known to increase embryo mortality in dairy cattle. Short-term elevation in temperature of mouse embryos to 43 degrees C (acute) has been shown to induce intracellular production of heat-shock proteins. In this study, in vitro development of bovine embryos was assessed during short-term (60 h) coculture with oviduct epithelial cells at 38.6 degrees C (T1), 40 degrees C (T2), 38.6 degrees C after a prior pulse treatment (20 min) at 43 degrees C with 5% CO2 (T3), or 38.6 degrees C after a prior pulse treatment (20 min) at 43 degrees C with 100% CO2 (T4). During incubation, embryos cocultured at 40 degrees C had a greater (P < .05) mean embryo development score at 36 h than embryos cocultured at 38.6 degrees C. At 60 h of incubation, embryo development scores were greater (P < .05) for embryos cultured at 38.6 degrees C than for those cocultured at 40 degrees C. The number of embryos hatched at 60 h was similar after coculture at 38.6 degrees C (T1) or a prior pulse treatment with 5% CO2 and 43 degrees C (T3), but the embryo development score at 60 h was greater (P < .05) for the pulse-treated embryos. Embryos in T4 had greater (P < .05) embryo development scores than did T1 embryos from 36 through 60 h. Pulse treatment (T4) resulted in a greater (P < .05) number of hatched embryos at 60 h than T1, T2, and T3. These results indicate a detrimental effect of a chronic elevation in temperature that was evident shortly after embryo hatching.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Ovarian follicular characteristics, embryo recovery, and embryo viability in heifers fed high-fat diets and treated with follicle-stimulating hormone.

Postpubertal beef heifers (n = 55) were used to examine the effects of high-fat diets, independently of energy intake, on nonesterified fatty acid and lipoprotein metabolic patterns, ovarian follicular dynamics, and embryo recovery/viability after FSH superstimulation. High-lipid (HL) diets (5.4% added fat) increased (P < .01) serum concentrations of cholesterol, but not of nonesterified fatty acids, during the 35-d period before FSH treatment. Development of medium-sized (5 to 9.9 mm) follicles was enhanced (P < .05) during this period in heifers fed the HL diet. The HL diet increased total cholesterol (P < .05) and progesterone (P = .14) concentrations in follicular fluid obtained at ovariectomy (n = 10) 60 h after the onset of FSH treatment, but neither estradiol-17 beta nor androstenedione was affected. Granulosa cells recovered from FSH-induced, estrogen-active follicles in heifers fed the HL diet produced greater quantities of progesterone (P = .06) and less estradiol-17 beta (P < .05) in vitro than did granulosa cells from heifers fed the normal lipid diet. Dietary treatment did not influence FSH-stimulated recruitment of medium and large follicles, number of ovulations, embryo recovery, or embryo viability. Data suggest that increments in dietary fat intake can alter specific aspects of ovarian steroidogenic potential and can increase the population of medium-sized follicles theoretically available for maturation and harvest during the estrous cycle. However, conditions that limited the latter process in the current experiment are not understood and require further investigation.

Animals↗
PubMed1992

Luteal maintenance in cattle after conceptus death during the first trimester of gestation.

The objectives of this experiment were to evaluate effect of age of the conceptus at death on subsequent interval to estrus and to determine whether prostaglandin F2 alpha (PGF) treatment after induced conceptus death would reduce interval to estrus. Sixty-four beef cows were diagnosed pregnant by ultrasonography between 24 and 50 d of gestation. Nine pregnancy groups were identified; each encompassed a 3-d interval from d 24 through 50 of gestation. Cows were allocated at random within pregnancy group to be treated with colchicine to induce conceptus death. Forty-eight hours after colchicine treatment, conceptus death was verified by ultrasonography and each animal received either saline or PGF. There was no evidence of an effect of age of conceptus at death on the subsequent interval to estrus after either saline or PGF. Interval to estrus after saline was 13.5 +/- .8 d, which was greater (P less than .01) than the 6.2 +/- .8 d after PGF. After saline, the estimate for the linear effect of time on serum progesterone (P4) was -1.32 +/- .36 ng/d and was less (P less than .05) than -2.83 +/- .36 ng/d for cows given PGF. Cows were exposed to fertile bulls at the first postabortion estrus. Pregnancy rates were 37.5% for cows given saline vs 31.3% for those given PGF. These results indicate that interval to estrus after conceptus death between 24 and 50 d of gestation is not affected by the age of the conceptus and can be reduced by PGF treatment.

Animals↗
PubMed1992

Evaluating two different evaporative cooling management systems for dairy cows in a hot, dry climate.

Milk production, rectal temperature, live weight gain, reproductive performance, and weather data were obtained on 150 Holstein cows managed under two cooling systems on a large dairy farm in Saudi Arabia during the summer months. Cows were paired at the onset of the trial according to days postpartum, lactation number, and current milk production. Females were then allocated either to a system that forced air, precooled by evaporative cooling, over the cows or to a system that alternately showered a fine mist onto the surface of the cows and then forced air at ambient temperature over them. The cows receiving evaporative cooling and those with spray and fan cooling were on sand and on slatted concrete floor, respectively, during the periods of cooling. The onset of estrus was observed during the night when the cows preferred the unshaded corral. For the 120-d trial period, 84% (62 of 75) of the cows receiving evaporative cooling and 60% (44 of 75) of the cows receiving spray and fan cooling became pregnant. In the evaporative cooling system, the pregnancy rate per insemination was 35.2% (179 inseminations) versus 23.2% (194 inseminations) for spray and fan cooling. The mean postpartum interval to pregnancy was 117.6 d for the evaporative cooling cows and 146.7 d for spray and fan cooling cows. The evaporative cooling system, with its open shades and sand bedding, enhanced reproductive performance and milk production compared with that of cows cooled with a spray and fan system with slatted flooring in this hot climate.

Air Conditioning↗
PubMed1991

Laryngotracheoesophageal cleft (type IV): management and repair of lesions beyond the carina.

Since the first successful repair of a complete laryngotracheoesophageal cleft (LTEC) to the carina in 1982, three newborn infants were observed with a particularly difficult variant in which the cleft extends beyond the carina into the mainstem bronchi. This type IV LTEC creates a long common tracheoesophagus, whose successful separation requires meticulous preoperative, operative, and postsurgical care. Three infants had complete surgical repair at our institution at 29, 49, and 225 days old and survived a minimum of 8 months. Recurrent tracheoesophageal fistulae at the thoracic inlet occurred in two infants, but was not observed in one patient when sternocleidomastoid muscle was interposed between the trachea and esophagus in the neck. Microgastria is an associated finding in each infant with the tracheoesophageal cleft extending beyond the carina. The small stomach is problematic as it is anatomically inadequate for any antireflux procedure and has not grown well, even with prolonged feeding. Early cleft repair is essential to prevent the development of chronic lung disease secondary to recurrent aspiration. The techniques to make the diagnosis, the preferred treatment to initially protect the airway, a single-stage operation performed simultaneously through the chest and neck to definitively repair the cleft, and finally the intraoperative and postoperative management critical for an optimal outcome are described.

Abnormalities, Multiple↗
PubMed1990

Prevalence of udder bacteria in milk samples from four dairy goat herds.

The prevalence of udder bacterial infections in 4 commercial goat herds in New South Wales was examined. Coagulase negative staphylococci were the predominant bacteria isolated being cultured from 13.3% of the 896 halves tested. Other bacteria isolated were Staphylococcus aureus (less than 1% of halves), streptococci (0.6%) and coliforms (2.0%). The low prevalence of udder bacteria contributing to the contamination of the milk was attributed to the milking management practices carried out in these herds, in particular pre-milking and post-milking antisepsis.

Animals↗
PubMed1990

Validation of the alexithymia construct: a measurement-based approach.

Alexithymia is a hypothetical personality construct that has been associated with a variety of medical and psychiatric disorders. This article reviews a program of research evaluating the validity of the construct using a measurement-based, construct validation approach. For this purpose the Toronto Alexithymia Scale (TAS) was developed. In a series of studies the TAS demonstrated internal consistency, good test-retest reliability, and a stable factor structure theoretically congruent with the alexithymia construct. In separate tests of construct validity, the TAS correlated in a theoretically meaningful fashion with measures of other constructs. Criterion validity was supported by a study in which the TAS was able to discriminate between behavioural medicine outpatients designated as alexithymic and those designated as nonalexithymic on the basis of objectively rated structured interviews. In a normal adult sample, TAS scores were not related to sociodemographic variables or intelligence. These results provide considerable empirical support for the validity of the alexithymia construct. In addition, the TAS appears to be a psychometrically sound measure of alexithymia that may prove useful in testing the construct with psychiatric and medical patient populations.

Adolescent↗
PubMed1989

The first international conference on the Palliative Care of the Elderly: an overview.

The effort to examine and improve palliative care for the elderly is actively joined. In Europe, Scandinavia, and North America, at least, issues are slowly being examined in clinical research. The response to the conference was enthusiastic, and new information emerged, for example: British Columbia's "Levels of Intervention" guidelines, Dr Doyle's description of new developments in Geriatric and Palliative Care training and service in the United Kingdom, Dr Triau et al's (Psychogeriatric Nursing Home, Leuven, Belgium) normalization model of care for dementia, and Dr Rory Fisher's argument that instead of using negative DNR orders in palliative care we should instead take a positive approach of specifying what palliative care can provide. Palliative care is not "no treatment;" increasingly we are able to be concrete and specific in our ability to prescribe a range of measures to ensure that our dying elderly die in comfort and without medical, legal, or social intrusion.

Aged↗
PubMed1988

Duplications of the alimentary tract. Clinical characteristics, preferred treatment, and associated malformations.

Duplications of the alimentary tract are unusual congenital anomalies that frequently present a diagnostic as well as therapeutic challenge to the surgeon. Because these lesions occur so infrequently, they are often not suspected until encountered intraoperatively. Due to the complicated anatomy and common blood supply shared between the duplication and associated native bowel, appropriate management requires a familiarity with the anatomy and clinical characteristics of this entity. To better define the range of patient characteristics, clinical presentation, and preferred therapy, 20 enteric duplications were reviewed in 17 patients treated at the Children's Hospital Medical Center from 1956 to 1986. Ages of patients ranged from 1 day to 11 years; 60% were less than 2 years of age at initial presentation. Seven duplications in six patients involved alimentary tract structures of foregut derivation (esophagus, stomach, and Parts I and II of duodenum), with a predominance of girls (4 of 6). Most of these patients (67%) presented with moderate to severe acute respiratory distress and a mass present on chest radiograph. In 67% of the patients, the correct diagnosis was established before operation. None required emergency operative intervention. By contrast, 13 duplications in 11 patients were of midgut or hindgut derivation (Parts III and IV of the duodenum, jejunum, ileum, and colon). In this group of patients, 62% of the duplications involved the cecum, 23% involved the ileum, and 16%, the jejunum. Seventy-eight per cent of the patients were boys. The most common symptoms were nausea and vomiting, and the most common sign was a palpable abdominal mass. Emergency operative intervention was required of eight of 11 patients with duplications involving the small bowel and colon. Three patients presented with an intussusception, four with signs and symptoms consistent with acute appendicitis, one with a small bowel obstruction, and two with gastrointestinal hemorrhage due to the presence of ectopic gastric mucosa within the duplication. It was found that two important points must be considered in regard to the management of enteric duplications: (1) the common blood supply shared between the duplication and native bowel must be carefully protected to avoid undue sacrifice of normal bowel, and (2) the presence of heterotopic gastric mucosa in 35% of patients negates internal drainage.(ABSTRACT TRUNCATED AT 400 WORDS)

Abnormalities, Multiple↗
PubMed1986

Villous tumors of the duodenum.

Nineteen cases of villous tumors of the duodenum are reported. They have a predilection for the ampullary region, tend to present with obstructive jaundice, especially if malignancy is present, and have a high prevalence of cancer (12 of 19, or 63%). Even when biopsies are available, the diagnosis of cancer is frequently missed (5 of 9 proven cancers, 56% false-negative rate), and it may be impossible to assess the presence of carcinoma in situ or invasive carcinoma without complete excision of the lesion. The authors' experience suggests that some small benign ampullary villous adenomas or those with carcinoma in situ can be excised locally but that pancreaticoduodenectomy is preferable in the fit patient for better local control both of extensive benign lesions and cancers without distant metastases.

Adenoma↗
PubMed1976

Epithelial and surfactant changes in influenzal pulmonary lesions.

Pulmonary epithelial cell destruction in mice infected with PR8-A influenza virus has been studied with light and electron microscopy and enzyme histochemistry, and correlated with pulmonary surfactant activity. All epithelial cell types were infected by the virus, resulting in destruction, pneumonitis, and atelectasis by seven to ten days. Pulmonary surfactant activity decreased progressively following onset of infection, and was minimal by seven to ten days. Before types 1 and 2 alveolar pneumocytes regenerated, the regenerating bronchial cells grew peripherally into some of the denuded alveolar ducts and alveoli to form epithelial nodules. Eventually the types 1 and 2 pneumocytes regenerated to cover the alveolar surfaces that were not invaded by bronchial epithelium. This regeneration was associated with increased surfactant activity in the postinfluenzal lesions, suggesting that the type 2 pneumocytes are a source of surfactant.

Animals↗