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Biomedical subjects

L A Nelson

Publications and source records attributed to L A Nelson.

At least 19 recordsLinked to original sources
PubMed2001

Epithelial permeability is not increased in rats following small bowel resection.

BACKGROUND: Increased intestinal permeability and translocation of bacteria and/or bacterial products may cause infection and liver dysfunction in patients with the short bowel syndrome. In previous studies, serum from mice undergoing small bowel resection (SBR) enhanced growth of cultured rat intestinal epithelial cells (RIEC-6), implicating a role for a serum factor(s) in the enterocyte response to SBR. These experiments tested the hypothesis that epithelial cell permeability is increased following SBR. MATERIALS AND METHODS: Male Sprague-Dawley rats underwent a 75% SBR or sham operation. Intestinal permeability in the remnant ileum was determined by Ussing chambers on Postoperative Day (POD) 3. Additionally, serum was collected on POD 1, 3, and 7 and mesenteric lymph was harvested on POD 3. Once confluent, RIEC-6 cells were incubated for 3 days in media supplemented with 10% fetal bovine serum (FBS; control), 1% FBS, 1% FBS plus 9% Sham serum, or 1% FBS plus 9% SBR serum or exposed to media with varied concentrations of SBR or Sham lymph. Monolayer permeability was determined by measuring the passage of dextran-rhodamine. RESULTS: Intestinal permeability was reduced in rats undergoing SBR. Sham serum-treated monolayers demonstrated the greatest permeability. Incubation with SBR serum reduced permeability to near control media. There were no permeability differences between SBR and Sham lymph-treated monolayers. CONCLUSION: The early adaptive response of the remnant intestine after SBR is associated with reduced permeability. These results suggest an alternative mechanism for the increased bacterial translocation that has been described following SBR.

Adaptation, Biological↗
PubMed2001

Intestinal adaptation: structure, function, and regulation.

After massive small bowel resection (SBR), the remnant intestine undergoes an adaptive process characterized by increases in wet weight, protein and DNA content, villus height and crypt depth, and absorptive surface area. These changes are the result of a proliferative stimulus that increases crypt cell mitosis and augments cellular progression along the villus axis. Functionally, there is upregulation of the Na(+)/glucose cotransporter, Na(+)/H(+) exchanger, and other enzymes involved in intestinal digestion and absorption. These physiologic events are a compensatory response to the sudden loss of digestive and absorptive capacity by the remnant intestine. A major consequence of inadequate intestinal adaptation is lifelong dependence on parenteral nutrition, which results ultimately in cholestatic liver dysfunction. Furthermore, adaptation may be associated with changes in intestinal permeability and an increased risk of bacterial translocation and sepsis. Several mediators thought to be integral to the postresection adaptive response have been proposed, including luminal nutrients, gastrointestinal secretions, and humoral factors. A thorough understanding of intestinal adaptation will be essential in the rational development of new and innovative therapies that amplify this complex but important process.

Animals↗
PubMed2001

The combined use of bupropion, lithium, and venlafaxine during ECT: a case of prolonged seizure activity.

There is limited literature addressing the safety of administering electroconvulsive therapy (ECT) to patients concomitantly receiving bupropion monotherapy or in combination with other drugs that may alter the seizure threshold. We describe a prolonged seizure occurring during the first treatment of a course of ECT in an adult patient receiving long-term bupropion therapy, lithium, and venlafaxine.

Antidepressive Agents, Second-Generation↗
PubMed2000

Melancholic symptoms during concurrent olanzapine and fluoxetine.

The concomitant use of olanzapine and fluoxetine has been advocated for the treatment of various psychiatric disease states. We describe a case in which the combination of olanzapine and fluoxetine appears to have caused the psychopathology of melancholic depression requiring hospitalization in a 40-year-old female. Postulated mechanisms for this drug interaction, particularly CYP450 isoenzyme inhibition by fluoxetine, is discussed.

Adult↗
PubMed2000

Asthma severity, psychophysiological indicators of arousal, and immune function in asthma patients undergoing biofeedback-assisted relaxation.

Asthma is characterized by airway hyper-responsiveness, inflammation, and reversible obstruction. Respiratory tract infection, allergies, air pollution, and psychosocial factors impact the severity and frequency of asthma symptoms. Pharmacotherapy and self-care are the major components in the management of asthma, but behavioral interventions also have the potential to affect asthma morbidity. We conducted a small, randomized controlled study, examining the effects of biofeedback-assisted relaxation in 16 nonsmokers with nonsteroid-dependent mild asthma. Data were collected on asthma symptoms, pulmonary function, indicators of arousal, and cellular immune factors. The trained group evidenced a decrease in forehead muscle tension in comparison to the controls, but no changes in peripheral skin temperature. Decreases in asthma severity and bronchodilator medication usage for the experimental group were observed. Pulmonary function testing revealed a significant difference between groups in FEV1/FVC at posttest, with the E group having a higher ratio than the controls. The cellular immune data showed no significant group differences in total white blood cell or lymphocyte counts, but decreases over time were observed. Significant differences were observed in the numbers of neutrophils and basophils in the trained group compared to controls, which supports the concept of decreased inflammation. Results of delayed-type hypersensitivity skin testing suggested enhanced function, but they were not conclusive. These findings, though limited by size of population, suggest a positive effect of biofeedback-assisted relaxation in young, nonsteroid-dependent asthmatics. The mechanisms underlying linkages between psychological, behavioral, and immune responses in asthma require further study.

Adolescent↗
PubMed1998

The application of volume deformation to three-dimensional facial reconstruction: a comparison with previous techniques.

Facial reconstruction has been widely criticised for its subjective nature and is thus often viewed as a last resort. Recent computer-aided reconstructions, which claim to be objective, may be subject to similar errors. To date, both manual reconstructions and computer-aided techniques have been limited to using the same tissue depth data reference tables. We propose that it is not solely the accuracy of the soft tissue depth data, but the sparsity of landmarks, which contributes to a lack of understanding of how soft tissue changes between the landmarks. The authors feel that a new approach to facial reconstruction using a computer graphics technique known as volume deformation addresses some of the problems encountered in the past. A review of previous methods is provided with discussion of the strengths and limitations of these techniques. In addition, areas are highlighted where the new deformation-based approach may offer possible solutions.

Computer Graphics↗
PubMed1998

Burn injury.

An important element in the care of burns, which affect more than 2.5 million Americans per year, is a multidisciplinary team approach. Nurses are important members of the team, which also includes physicians, physical and occupational therapists, psychologists, rehabilitation counselors, and nutritionists among others. Regular communication with the team is important for consistent quality care.

Bandages↗
PubMed1996

Allograft tolerance by intrathymic donor splenocyte transfer: an age-dependent, species-specific phenomenon?

Protocols that allow allograft survival without immunosuppression remain the ultimate goal in transplantation. Intrathymic injection of donor splenocytes into a transiently immunosuppressed recipient has induced tolerance to a variety of subsequently transplanted allografts in rats. The purpose of this study was to determine if recipient age is critical to intrathymic tolerance in light of age-dependent thymic changes, and if this protocol can be extended to an outbred, large animal model. Prepubertal and postpubertal Wistar-Furth rats underwent intrathymic injection of splenocytes from Lewis rats and antilymphocyte serum (ALS) intraperitoneally. On day 21, a heterotopic Lewis heart was transplanted, with graft survival evaluated by cardiac palpation. Graft tolerance (> 100 days) occurred in four out of five (80%) of the prepubertal rats compared to two out of six (33%) postpubertal rats. Tolerance was not demonstrated in rats receiving intrathymic injection of buffer only. In puppies, groups 1 and 2 underwent splenectomy with intrathymic injection of allo splenocytes. Control puppies (group 3) received intrathymic auto splenocytes. Groups 1 and 3 were given antilymphocyte gamma globulin (ALG) on days 7 to 0 with respect to the intrathymic injection. Group 2 did not receive ALG, but instead received cyclosporin A (CSA) on days 0-2. On day 21, all puppies underwent bilateral nephrectomy and single renal transplantation. No additional immunosuppression was given. Tolerance (creatinine < 7 mg/dl for 100 days) was not obtained by any dog in all three groups. There was no difference in graft survival between control and experimental dogs, with the longest surviving graft seen in a control dog (26 days). Our results suggest that thymic change during maturation may alter the ability to induce tolerance by intrathymic injection of donor cells in rats, and that the protocol is not easily adapted to large animals.

Age Factors↗
PubMed1993

Antibodies to phospholipids and nuclear antigens in non-pregnant women with unexplained spontaneous recurrent abortions.

In a collaborative study of 73 non-pregnant Kuwaiti women with unexplained spontaneous recurrent abortion (RSA), 30 control healthy non-pregnant multiparous Kuwaiti women and 20 North American women who received elective abortion(s), autoantibodies to 6 phospholipids and 9 nuclear antigens were measured. Women with recurrent spontaneous abortions demonstrated 3 times higher incidence of antibodies to phospholipids (30.1%) than controls (10% each) (P = 0.029). The incidence of both IgM and IgA class antiphospholipid antibodies were significantly higher than those of controls. The incidence of antibodies to cardiolipin in women with recurrent spontaneous abortions (12.3%) was significantly higher than those of controls (P = 0.035) and incidence of IgM but not IgG anticardiolipin antibody was significantly higher in women with RSAs than in controls (P = 0.053). The incidences of anti-polyinosinic acid (P = 0.035) and anti-histone 1 antibody (P = 0.052) were significantly higher in women with recurrent spontaneous abortions than controls. There was no significant difference in the incidence of autoantibodies between primary and secondary aborters. However, women with a history of second trimester abortions showed a higher incidence of antiphospholipid antibodies than women with first trimester abortions only. Recurrent spontaneous abortion is associated with autoantibodies to phospholipid epitopes including IgA antiphospholipid antibodies.

Abortion, Habitual↗
PubMed1989

Performance contracting: the Colorado model.

Through a process of negotiation between a community mental health centers association (CMHCA) and the state division of mental health (DMH), a performance contracting system has created entrepreneurial freedom for the mental health centers while still providing adequate controls by the DMH.

Colorado↗
PubMed1989

Periodic hyperammonemic encephalopathy associated with a ureterosigmoidostomy.

Ureterosigmoidostomy, a urinary diversion procedure performed for treatment congenital urologic defects or bladder cancer, may be associated with hyperammonemia. A delayed periodic encephalopathy, characterized by dysarthria, ataxia, and coma, developed in a 44-year-old woman who had undergone this procedure. Hyperammonemia-associated neurotoxicity resolved after surgical revision of the ureterosigmoidostomy to a uretero-ileostomy. Therefore, a treatable episodic encephalopathy may occur in association with hyperammonemia in patients who have undergone ureterosigmoidostomy.

Adult↗
PubMed1989

Synthesis and cytotoxic activity of pyridylthio, pyridylsulfinyl, and pyridylsulfonyl methyl acrylates.

Nineteen 2-pyridylthio (2), 2-pyridylsulfinyl (3) or 2-pyridylsulfonyl (4) derivatives of (Z)-methyl acrylate were synthesized in order to investigate the effect of the oxidation state of the sulfur atom, and the position and nature of pyridyl substituents on cytotoxic activity. Analogous sulfinyl and sulphonyl derivatives were equipotent, and more potent than analogous thio derivatives, in an vitro L1210 screen. In most cases, incorporation of nuclear trifluoromethyl and chloro substituents at various positions of the pyridyl ring of the sulfinyl derivatives (compounds 3b-3h) decreased activity relative to the unsubstituted sulfinyl 3a (ED50 0.43 micrograms/ml). Compounds 3b, 3d and 3i exhibited weak antineoplastic activity in an in vivo P388 screen at a dose of 5 mg/kg.

Animals↗