Biomedical subjects

D Baum

Publications and source records attributed to D Baum.

At least 19 recordsLinked to original sources

PubMed1995

Functional interactions of T cells with endothelial cells: the role of CD40L-CD40-mediated signals.

CD40 is expressed on a variety of cells, including B cells, monocytes, dendritic cells, and fibroblasts. CD40 interacts with CD40L, a 30-33-kD activation-induced CD4+ T cell surface molecule. CD40L-CD40 interactions are known to play key roles in B cell activation and differentiation in vitro and in vivo. We now report that normal human endothelial cells also express CD40 in situ, and CD40L-CD40 interactions induce endothelial cell activation in vitro. Frozen sections from normal spleen, thyroid, skin, muscle, kidney, lung, or umbilical cord were studied for CD40 expression by immunohistochemistry. Endothelial cells from all tissues studied express CD40 in situ. Moreover, human umbilical vein endothelial cells (HUVEC) express CD40 in vitro, and recombinant interferon gamma induces HUVEC CD40 upregulation. CD40 expression on HUVEC is functionally significant because CD40L+ Jurkat T cells or CD40L+ 293 kidney cell transfectants, but not control cells, upregulate HUVEC CD54 (intercellular adhesion molecule-1), CD62E (E-selectin), and CD106 (vascular cell adhesion molecule-1) expression in vitro. Moreover, the kinetics of CD40L-, interleukin 1-, or tumor necrosis factor alpha-induced CD54, CD62E, and CD106 upregulation on HUVEC are similar. Finally, CD40L-CD40 interactions do not induce CD80, CD86, or major histocompatibility complex class II expression on HUVEC in vitro. These results demonstrate that CD40L-CD40 interactions induce endothelial cell activation in vitro. Moreover, they suggest a mechanism by which activated CD4+ T cells may augment inflammatory responses in vivo by upregulating the expression of endothelial cell surface adhesion molecules.

Antigens, CD↗

PubMed1995

Insulin dependent diabetes in children under 5: incidence and ascertainment validation for 1992.

OBJECTIVE: To establish the incidence of insulin dependent diabetes diagnosed in children under 5 years of age in the British Isles during 1992, comparing the national and regional results with those of our 1988 national study, and estimating the 1992 study's level of case ascertainment. DESIGN: Active monthly reporting of cases by consultant paediatricians through the framework of the British Paediatric Surveillance Unit, with additional reports from specialist diabetes nurses and regional health authorities. SUBJECTS: All children diagnosed under the age of 5 years with primary insulin dependent diabetes from 1 January to 31 December 1992 (inclusive) and resident in the British Isles at diagnosis. RESULTS: 387 children (208 boys and 179 girls) were confirmed to have insulin dependent diabetes, giving a national incidence of 9.3/100,000/year. This is similar to the 9.9/100,000/year found in 1988. Three sample capture-recapture analysis, which could only be applied across the 12 (out of 18) regions supplying regional information to the study, suggested ascertainment rates of 78% for the British Paediatric Surveillance Unit, 67% for specialist nurses, 69% for regional health authorities, and 99% for the aggregated registry. CONCLUSIONS: The national incidence of diabetes in the under 5s in the British Isles did not differ between 1988 and 1992. Nearly complete (99%) ascertainment of cases was possible only for regions for which three data sources were available. Capture-recapture analysis highlighted both the need for more than one data source and for each data source to be complete for the whole study area.

Age Factors↗

PubMed1995

Ligation of CD40 on fibroblasts induces CD54 (ICAM-1) and CD106 (VCAM-1) up-regulation and IL-6 production and proliferation.

CD40 was originally described as a functionally significant B cell surface molecule. However, CD40 is also expressed on monocytes, dendritic cells, epithelial cells, and basophils. We now report that synovial membrane (SM) or dermal fibroblasts also express cell surface CD40 in vitro. Fibroblast CD40 expression declines with increasing time in culture and recombinant interferon-gamma (rINF-gamma) induces fibroblast CD40 up-regulation. This effect of rINF-gamma is augmented by recombinant interleukin-1 alpha or recombinant tumor necrosis factor-alpha. CD40 expression on fibroblasts is functionally significant because CD40L-CD40 interactions induce SM fibroblast CD54 (intercellular adhesion molecule-1) and CD106 (vascular cell adhesion molecule-1) up-regulation. Moreover, ligation of CD40 augments IL-6 production by SM fibroblasts and induces fibroblasts to proliferate. In addition, rINF-gamma enhances the effect of CD40L-CD40 interactions on fibroblast proliferation. Taken together, these studies show that fibroblasts can express CD40, cytokines can regulate fibroblast CD40 expression, and CD40 ligation induces fibroblast activation and proliferation.

Animals↗

PubMed1994

Pediatric cardiac transplantation. The Stanford experience.

BACKGROUND: Cardiac transplantation for children with endstage heart disease has become an accepted form of therapy and is being practiced with increasing frequency and improving short-term outcome. METHODS AND RESULTS: To assess the medium-term outcome of pediatric cardiac transplantation, we analyzed our experience with 72 patients under the age of 18 (range, 0.1 to 17.7 years; mean, 9 +/- 6.4 [SD]) who underwent orthotopic cardiac transplantation at Stanford University between 1977 and 1993. There were 38 male and 34 female patients. Preoperative diagnoses included congenital heart disease in 24 (33%), idiopathic cardiomyopathy in 27 (37%), viral cardiomyopathy in 12 (17%), and familial cardiomyopathy in 7 (10%) patients. Immunosuppressive management has evolved over time and has included a tapering schedule of steroids, azathioprine, rabbit antithymocyte globulin, cyclosporine in all patients after 1980, and induction with OKT3 since 1987. Operative mortality rate was 12.5 +/- 4.0% (mean +/- 70% confidence intervals). Actuarial survival estimates at 1, 5, and 10 years are 75 +/- 7.1%, 60 +/- 6.4%, and 50 +/- 8.1% (mean +/- 1 SEM), respectively. Causes of death included infection in 8 (28% of deaths), rejection in 7 (24%), graft coronary disease in 5 (17%), pulmonary hypertension in 4 (14%), and nonspecific graft failure in 2 (7%) patients. Survival rates were similar for patients over and those under age 10 years (including the infant cohort of 18 patients transplanted since 1986). Currently, there are 43 patients alive, all in New York Heart Association functional class I. Only 22 +/- 5.6% of patients were free of rejection at 1 year, but 86 +/- 5.4% were free of rejection-related death at 10 years. At 1 year, only 37 +/- 6% of patients were free from any infection, but 88 +/- 4.2% remained free of infection-related death at 5 years. Actuarial freedom from graft coronary artery disease (angiographic or autopsy proven) was 85 +/- 6.6% at 5 years and from coronary artery disease-related death was 91 +/- 4.7%. CONCLUSIONS: These data demonstrate satisfactory medium-term outcome of cardiac transplantation in selected pediatric patients with end-stage heart disease, but further progress is necessary to more effectively control rejection, infection, and graft coronary disease.

Actuarial Analysis↗

PubMed1993

Nursing frequency and the energy intake from breast milk and supplementary food in a rural Thai population: a longitudinal study.

A group of 60 infants representative of a rural Thai population were studied longitudinally over the first year of life. Their breast milk intake, supplementary food intake and nursing patterns were measured for 2 consecutive days at about 15, 45, 90, 180, 270 and 360 days of age. For the sample as a whole, the estimated peak value for energy intake from breast milk was 529 kcal (2213 kJ) and occurred at 34 days post-partum. Thereafter milk intake declined, with 40% of infants fully weaned by the end of the first year. Supplements were introduced early, with 15% of infants supplemented by 2 weeks and 68% by 6 weeks. Higher levels of supplementation were associated with lower breast milk intake. In addition there was an independent positive effect of nursing patterns (number of breast feeds per day). Interaction terms show that both supplementary feeding and number of feeds have quantitatively different effects at different ages: breast milk intake varies more with level of supplementation in younger infants than in older infants, and varies more with number of feeds in older infants than in younger infants. Higher peak levels of breast milk intake were followed by a steeper decline, and infants who took more breast milk at 15 days were more likely to be fully weaned by their first birthday.

Age Factors↗

PubMed1993

Neoplastic disorders after pediatric heart transplantation.

BACKGROUND: Because of their life-long requirement for immunosuppressive therapy, neoplastic disorders could represent a significant threat to long-term survival in infants and children after heart transplantation. This study determined the incidence and clinical spectrum of neoplastic disorders in 80 pediatric patients who underwent heart transplantation between 1974 and 1992. METHODS AND RESULTS: Follow-up ranged from 6 to 189 months (mean, 50.0 months). Tumors occurred in 10 patients (12.5%). Time to detection ranged from 3.3 to 139.2 months (mean, 52.7 months). Tumor incidence was greatest in 9 patients transplanted before the cyclosporine era (44%) compared with the subsequent 71 patients (8.5%, P < .05). There was no increase in risk related to sex, age, underlying disease, or blood type; however, patients with tumors received higher initial doses of cyclosporine and prednisone and had more rejection episodes in the first 3 months (P < .05). There was an increased risk associated with anti-thymocyte globulin (33%, P < .05) but not with OKT3 (6%, P = NS). There were eight lymphoproliferative disorders (four B-cell, one T-cell, three not determined) and one hepatocellular and one squamous cell carcinomas. Six cases of lymphoproliferative disorder had in situ evidence of Epstein-Barr virus. Patients were treated by reducing immunosuppression (7), radiotherapy (2), and chemotherapy (1). There were five deaths: two tumor related and the others due to rejection, renal failure, and infection. Of 5 survivors, 1 had tumor recurrence 4 years after diagnosis, and 4 are disease free. CONCLUSIONS: Tumors represent a small but serious long-term risk to pediatric heart transplant recipients. The incidence in children transplanted in the cyclosporine era is similar to that in adults, and the majority of tumors are lymphoproliferative disorders that often regress by reducing immunosuppression.

Actuarial Analysis↗

PubMed1992

Heart, heart-lung, and lung transplantation in the first year of life.

Seventeen infants less than 1 year of age have undergone heart (12), heart-lung (3), and lung (2) transplantation for end-stage cardiopulmonary disease. The infants undergoing heart transplantation had a mean age of 4.5 months (range, 19 days to 12 months) with the diagnosis of cardiomyopathy in 4 and congenital heart disease in 8. Four of the 8 patients (50%) had hypoplastic left heart syndrome. Actuarial survival at 1 and 2 years was 74% and compared favorably with the survival of older children at 1 and 2 years of 82% and 69%. The linearized rejection rate was less in infants as compared with children more than 1 year of age (0.61 versus 1.48 episodes per 100 patient days). In intermediate follow-up, no graft atherosclerosis has been noted. Immunosuppression has included a three-drug protocol of cyclosporine, azathioprine, and prednisone. A steroid taper to alternate day steroids or off completely by 6 months has been the goal and has been accomplished in 6 of 12 infants. Heart-lung and lung transplantation has been performed in 5 infants. One infant in each group died: 1 infant secondary to airway complications and sepsis and another due to pulmonary sepsis. A pulmonary lobe from a larger and older donor was transplanted into a 4-week-old infant as a single-lung transplant with good outcome. The 3 surviving infants are well 24, 18, and 2 months after transplantation. Obliterative bronchiolitis has not been clinically apparent in this group. These data support the clinical efficacy of heart, heart-lung, and lung transplantation in the first year of life.

Actuarial Analysis↗

PubMed1992

Cardiac growth after pediatric heart transplantation.

BACKGROUND: To assess whether normal cardiac growth occurs after heart transplantation in the pediatric age group, we performed a study of 13 infants and children who underwent orthotopic heart transplantation at Stanford. METHODS AND RESULTS: The echocardiographic data from a population of 93 normal children were analyzed to determine estimates of the fifth, 25th, 50th, 75th, and 95th percentiles of the normal pediatric population. Growth curves for each of the cardiac dimensions were stratified into six classes representing each of the percentile bands, and dimensions for the 13 patients were tracked between early postoperative (early) and point of maximal follow-up (late). Results were compared by Student's paired t test to determine whether normal growth was occurring. The mean age at transplant was 5.0 +/- 1.3 years (mean +/- SEM) (range, 0.4-12.8 years), duration of follow-up was 3.1 +/- 0.4 years (1.3-5.8 years), and change in body surface area was 0.24 +/- 0.03 m2 (0.12-0.50 m2). Both right ventricular (RV) and left ventricular (LV) chamber dimensions were within the normal range at both early and late time points and grew normally as assessed by a lack of class changes. Early wall thickness measurements were above the 95th percentile in seven of 13 patients (LV), 12 of 13 patients (septum), and four of 13 patients (RV). Wall thickness measurements remained above normal, and there were no significant class changes at late follow-up. Histological examination in five patients showed markedly increased septal myocyte width, indicating myocyte hypertrophy. Atrial and great vessel anastomotic sites showed no evidence of obstruction by Doppler and catheterization studies. CONCLUSIONS: These data demonstrate that normal cardiac chamber dimensional growth occurs at greater than 3 years' follow-up after pediatric heart transplantation. Significant LV and septal (and to a lesser extent RV) hypertrophy persists and may have implications for long-term allograft growth and function.

Body Surface Area↗

PubMed1992

Current approach to hypoplastic left heart syndrome. Palliation, transplantation, or both?

Over the past 3 years, 35 newborn infants have been referred for surgical management of hypoplastic left heart syndrome. Surgical palliation (first-stage Norwood) or cardiac transplantation was offered. Twenty-four families (68%) chose palliation and 11 families (32%) chose cardiac transplantation. Of the 11 infants listed for cardiac transplantation, five underwent transplantation. Because of a lack of donors after an average wait of 25 days (19 to 31), the remaining six infants underwent palliation, with no perioperative deaths. Of the 30 infants undergoing palliation, including crossovers, 20 (67%) survived the first operative stage. Among the last 19 infants undergoing palliation in 1990, the early survival was 84%. Risk factors determined for poor outcome were year of operation (p less than 0.001) and circulatory arrest time greater than 50 minutes (p less than 0.001). Among the 13 infants undergoing palliation with a circulatory arrest time of less than 50 minutes, there were 12 survivors (92%); among 12 having a circulatory arrest time of more than 50 minutes, there were four survivors (33%). At intermediate follow-up, six infants have undergone second-stage procedures (Glenn), with five survivors. There were eight late deaths, four caused by respiratory infections and four caused by cardiac problems, including a thrombosed shunt in one infant. Three of five infants are alive and doing well after cardiac transplantation. Size of aorta, tricuspid regurgitation, and ventricular wall thickness did not prove to be risk factors. Given the existing data, we believe these infants should be managed selectively on the basis of donor availability and family wishes.

Actuarial Analysis↗

PubMed1991

The Chiang Mai lactation project: study design and implementation.

The Chiang Mai lactation project is a longitudinal field study of human lactation carried out among northern Thai women living in the Sanpatong area of Chiang Mai Province. Its aim was to measure the volume and composition of breast milk transferred from mothers to their infants in the first year postpartum, and to relate it to predictors of milk production, and to the growth of the child. Breast milk and supplementary food intake, and nursing patterns, were recorded over two consecutive 24-hour periods six times during the first year. Samples of breast milk and of supplementary foods were analysed for energy and protein. Supplementary foods were also analysed for bacterial contamination. The growth of the child was measured, and health assessed using a combination of health diaries and examination by a physician. Recruitment to the study was excellent. After recruitment, two subjects left the study area, but otherwise only two dropped out, so complete sets of data covering these variables are available for 58 of the 62 recruited subjects.

Body Weight↗

PubMed1991

Pediatric heart transplantation at Stanford: results of a 15-year experience.

The long-term results of pediatric heart transplantation were evaluated in 53 patients, aged 0.25 to 18.94 years, who received transplants at Stanford University Medical Center between 1974 and 1989. Indications for transplantation were idiopathic cardiomyopathy (68%), congenital heart disease (21%), endocardial fibroelastosis (8%), and doxorubicin cardiomyopathy (3%). Immunosuppression was achieved with combinations of cyclosporine, prednisone, and azathioprine. Thirty-seven of 42 recipients leaving the hospital after transplantation were alive and in New York Heart Association class I at study's end. Cumulative survival was 79% at 1 year, 76% at 3 years, and 69% at 5 years. Fourteen recipients have survived more than 5 years (5.1 to 12.4 years). Hospital readmission for illness has been infrequent, decreasing from 6.8 days to 0.9 days per year over 5 years. Eleven patients have required no rehospitalization. Posttransplant deaths were due to infection (19%), rejection (4%), pulmonary hypertension (4%), coronary artery disease (2%), and lymphoproliferative disease (2%). Retransplantation was required for intractable rejection in 4 patients and advanced coronary artery disease in 2. Hypertension and elevated blood urea nitrogen and creatinine levels were common in individuals receiving cyclosporine. Growth was often impaired in prepubertal children receiving daily prednisone. Based on this 15-year experience, it is concluded that heart transplantation represents a reasonable alternative for selected young patients with end-stage cardiac disease.

Adolescent↗

PubMed1990

Chicken growth hormone: cDNA-synthesis and base sequence.

1. Growth hormone (GH)-cDNA was synthesized from poly A(+)-mRNA extracts of chicken pituitary glands. 2. Chicken-cDNA library was cloned into E. coli. 3. Base sequence analysis of chicken GH-cDNA revealed only 70% similarity compared with duck GH-cDNA, and 97% similarity with a previously published chicken GH-cDNA sequence. 4. Dissimilarities in base sequences are primarily observed in the 3'-non-coding region of GH-cDNAs (chicken and duck). 5. Comparisons of amino acid sequences of chicken and duck GH exhibit only three substitutions, while the amino acid sequences of GHs of chicken are identical.

Amino Acid Sequence↗

PubMed1990

Adrenal cortical adenoma in the spinal canal of an 8-year-old girl.

An ectopic adrenal cortical adenoma containing high levels of androstenedione but without clinically detectable virilizing effects was found in the spinal intradural space of an 8-year-old girl. The tumor, which was located at the L2 level, manifested itself clinically by a short history of bilateral leg pain. It was well encapsulated; therefore, total surgical removal was accomplished. The light microscopic appearance of the tumor was typical of adenomatous adrenal cortical tissue. Ultrastructurally, it also showed characteristic features of steroid-producing tumors, including very abundant smooth endoplasmic reticulum and giant mitochondria with tubulovesicular and circular cristae. Frozen tissue analyzed by radioimmunoassay was found to contain almost 20 times the normal tissue level of androstenedione. There was no elevation of cortisol or aldosterone levels in the tumor. Postoperative magnetic resonance imaging (MRI) scan of the retroperitoneum showed no abnormalities in the patient's adrenal glands. Serum androstenedione levels were normal. We postulate that the adenoma developed from congenital ectopic rests of intraspinal adrenal tissue. Although ectopic occurrence of adrenal cortical tissue has been recorded in other areas, neither such rests nor tumors developing from them have been previously reported within the spinal canal.

Adenoma↗

PubMed1990

Pediatric heart transplantation.

Heart transplantation has been performed successfully in the pediatric age group for just over 10 years, yet early results are encouraging, and this procedure has moved from the realm of experimental therapy to that of accepted medical practice for certain specific conditions. In infants and children with cardiomyopathies or with congenital heart disease for which no reasonable standard surgical alternative exists, heart transplantation offers the best hope for long-term survival. Most important, in those patients surviving heart transplantation, rehabilitation has been almost universally complete. Although the long-term prospects for pediatric heart transplant patients are still unknown, we have now accumulated sufficient experience in adults suggesting the potential for decades-long survival. Future improvements in diagnosis and treatment of rejection and prevention of the complications of immunosuppressive therapy will continue to improve the prospects for lifelong survival in these patients.

Adolescent↗

PubMed1986

Adipose tissue thymidine kinase activity in man.

Thymidine kinase activity was studied during human adipose tissue development. Adipose tissue was obtained from the groin in 81 persons, aged 7 wk through 60 yr. None had a metabolic or growth disorder. Adipose tissue thymidine kinase activity was highest in infants and lowest in adults. Peak thymidine kinase activity was seen in the early postnatal period and a lesser elevation was found in the preadolescent years, coinciding with hypothesized periods of proliferation of preadipocytes in man. In contrast, during adulthood, a time of stable lipid-laden cell number, thymidine kinase activity was lower. Although these adipose tissue samples include both stromal and fat cells, the data support the hypothesis that adipose tissue growth in early infancy is primarily the result of cellular proliferation, and that little cellular proliferation occurs after infancy, except possibly for a brief period prior to adolescence.

Adipose Tissue↗

PubMed1986

Medication compliance in children with asthma.

The aim of the study was to determine whether self-management skills, when taught to asthmatic children and their parents, would improve medication compliance. The latter was assessed by a variety of procedures including serum theophylline levels, pill counts by parents, and self-monitoring measures. Results indicated a group receiving self-management training showed no greater gains in medication compliance, self-concept, or health locus of control than did a self-monitoring-only group. However, children in the former group became more responsible for initiating appropriate treatment for their attacks than did youngsters in the latter group.

Adolescent↗

PubMed1985

Pentobarbital effects on plasma catecholamines: temperature, heart rate, and blood pressure.

The effects of intravenous pentobarbital were studied in dogs. Plasma pentobarbital concentrations were inversely related to epinephrine and norepinephrine concentrations. Plasma catecholamines appeared fully suppressed at pentobarbital levels greater than 25-30 micrograms/ml. Furthermore, pentobarbital levels were negatively related to rectal temperature, heart rate, and mean blood pressure. The methods of pentobarbital administration influenced plasma pentobarbital as well as epinephrine and norepinephrine levels, temperature, heart rate, and blood pressure. These observations suggest the possibility that pentobarbital inhibits the sympathetic nervous system, which in turn may affect temperature, heart rate, and blood pressure. Because pentobarbital anesthesia affects plasma catecholamine concentrations, the regimen used in animal models requires consideration when interpreting data potentially influenced by the sympathetic nervous system.

Animals↗

PubMed1984

Pentobarbital anesthesia suppresses basal and 2-deoxy-D-glucose-stimulated plasma catecholamines.

Since pentobarbital anesthesia is known to attenuate certain autonomic reflexes, we tested whether pentobarbital would suppress both basal and stimulated levels of plasma catecholamines and whether a large stimulus might counterbalance this suspected suppression. In untrained dogs, sampled by venipuncture, pentobarbital (30 mg/kg iv) decreased the plasma concentration of epinephrine (E) from 146 +/- 9 to 38 +/- 8 (SE) pg/ml (n = 46) and norepinephrine (NE) from 276 +/- 13 to 91 +/- 10 pg/ml (both P less than 0.0005), suggesting that barbiturate anesthesia suppresses sympathetic outflow in these mildly stressed animals. Pentobarbital also had a marked suppressive effect on the lower baseline catecholamines (E, 84 +/- 14 pg/ml; NE, 118 +/- 10 pg/ml; n = 6) of trained, chronically catheterized dogs, suggesting that it was capable of suppressing resting sympathetic outflow as well. To determine whether pentobarbital anesthesia also suppressed reflex activation of the sympathetic nervous system, the plasma catecholamine response to the neuroglucopenic agent, 2-deoxy-D-glucose (2-DG), was measured in conscious and in pentobarbital-anesthetized dogs. In conscious dogs, the administration of 2-DG (100 mg/kg iv) doubled the base-line plasma concentration of E and NE 30 min after the 2-DG injection. In contrast, the administration of 2-DG (100 mg/kg iv) to pentobarbital-anesthetized dogs produced no significant increase of either plasma catecholamine, suggesting marked suppression of this sympathetic reflex.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗