bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of starvation and biofilm formation on acid resistance of Streptococcus mutans
Authors: Zhu M. , Takenaka S. , Sato M. , Hoshino E.
Published: March 2003

The aim of this study was to investigate acid resistance induced by starvation or biofilm formation in Streptococcus mutans ATCC 25175. The artificial biofilms were made on cover glasses, starved for 24 h and immersed in 0.1 M lactate buffer at pH 3.8 for 10 min. The biofilms were also exposed to 5% sucrose solution for 20 min to simulate acid shock produced by sucrose metabolism. Confocal laser scanning microscopy with fluorescein isothiocyanate staining measured the resultant minimum pH in biofilms. Live and dead organisms in biofilms were differentiated by confocal laser scanning microscopy with proidium iodide and SYTO9 staining. The same processes were used to treat planktonic organisms. The results showed that starved biofilms or planktonic cells showed significantly more viable bacteria after acid shock induced either by lactic acid or during sucrose consumption than non‐starved biofilms or planktonic cells. In addition, biofilms showed greater resistance to acid shock induced by lactic acid than planktonic cells, whereas similar results were obtained where sucrose was used as a carbon source to reduce pH in biofilms and planktonic cells. Thus, it is suggested that starvation protects both biofilm and planktonic S. mutans from acid shock induced either by lactic acid or during sucrose consumption, while biofilm formation seemed to protect bacteria only from acid shock induced by pH 3.8 lactate buffer but not the acid shock of a slightly higher pH produced during sucrose consumption.
Studies on the aminopeptidase activities of Porphyromonas gingivalis
Authors: Grenier D. , Gauthier P. , Plamondon P. , Nakayama K. , Mayrand D.
Published: March 2003

Porphyromonas gingivalis is an asaccharolytic bacterium that requires nitrogen substrates as carbon and energy sources. The aims of this study were to investigate the aminopeptidase activities of P. gingivalis and to evaluate the effect of aminopeptidase inhibitors on bacterial growth. Only arginine aminopeptidase and dipeptidyl aminopeptidase IV activities were detected. Experimental evidence was obtained suggesting that the Arg‐gingipains of P. gingivalis can function as both an endopeptidase and an aminopeptidase. Firstly, the arginine aminopeptidase activity was found to be inhibited by leupeptin, a well‐known inhibitor of Arg‐gingipain activity. Secondly, a preparation of Arg‐gingipain activity could hydrolyze the chromogenic substrate for arginine aminopeptidase. Lastly, a mutant of P. gingivalis constructed via gene disruption by use of suicide plasmids and deficient in both Arg‐gingipain A and B was also devoid of arginine aminopeptidase activity. To investigate the key role of aminopeptidase activities in growth of P. gingivalis, aminopeptidase inhibitors were incorporated in the culture medium prior to inoculation. Bestatin and actinonin were the only ones to inhibit growth of P. gingivalis. Their mechanism of growth inhibition appears to be different but does not involve inhibition of the two major aminopeptidase activities (arginine aminopeptidase and dipeptidyl aminopeptidase IV).
Porphyromonas endodontalis binds, reduces and grows on human hemoglobin
Authors: Zerr M. , Drake D. , Johnson W. , Cox C. D.
Published: March 2003

Porphyromonas endodontalis is a black‐pigmented, obligate anaerobic rod‐shaped bacterium implicated as playing a major role in endodontic infections. We have previously shown that P. endondontalis requires the porphyrin nucleus, preferably supplied as hemoglobin, as a growth supplement. The bacteria also actively transport free iron, although this activity does not support growth in the absence of a porphyrin source. The purpose of this study was to further investigate the binding and subsequent utilization of human hemoglobin by P. endodontalis.P. endodontalis binds hemoglobin and reduces the Fe(III) porphyrin, resulting in a steady accumulation of ferrous hemoglobin. Reduction of methemoglobin was similar to the extracellular reduction of nitrobluetetrazolium in the presence of oxidizable substrate. Turbidimetric and viable cell determinations showed that P. endodontalis grew when supplied only hemoglobin. Therefore, we conclude that hemoglobin appears to serve as a sole carbon and nitrogen source, and that these bacteria reduce extracellular compounds at the expense of oxidized substrates.
A possible mechanism of maxillofacial abscess formation: involvement of Porphyromonas endodontalis lipopolysaccharide via the expression of inflammatory cytokines
Authors: Murakami Y. , Hanazawa S. , Tanaka S. , Iwahashi H. , Yamamoto Y. , Fujisawa S.
Published: March 2003

In a previous study, we developed a specific monoclonal antibody against Porphyromonas endodontalis lipopolysaccharide, and demonstrated that this lipopolysaccharide was detected in bacterially infected root canal fluid. We suggest here that P. endodontalis lipopolysaccharide in the infectious materials plays a stimulatory role in maxillofacial abscess formation via the expression of inflammatory cytokines. Our epidemiological study showed that this lipopolysaccharide was detected in significant levels the infectious material of patients with periapical periodontitis and odontogenic abscesses. Interestingly, infectious material‐induced expression of tumor necrosis factor‐α, interleukin‐1β, or neutrophil chemoattractant KC genes in mouse macrophages, was significantly neutralized by monoclonal antibody against the lipopolysaccharide. In addition, we also detected a significant amount of tumor necrosis factor‐α in the infectious material. These results suggest that P. endodontalis lipopolysaccharide plays an important role in the pathogenic mechanism of maxillofacial abscess formation via the expression of inflammatory cytokines.
Actinobacillus actinomycetemcomitans induces apoptosis of T lymphocytes by the Fas and Fas ligand pathway
Authors: Nalbant A. , Zadeh H. H.
Published: March 2003

Actinobacillus actinomycetemcomitans expresses a number of toxins capable of inducing apoptotic cell death of T lymphocytes. However, the exact mechanism(s) has not been elucidated. The present study investigated the involvement of the Fas (CD95)‐mediated apoptotic pathway in A. actinomycetemcomitans‐induced T‐cell apoptosis. To that end, peripheral blood mononuclear cells (PBMC) were cultured with or without A. actinomycetemcomitans cell‐free culture supernatant (CFCS) for 0–96 h. The cells were then labeled with specific monoclonal antibodies and flow cytometry was performed. Results demonstrated up‐regulation of Fas and activation of caspase‐3 in T cells in response to A. actinomycetemcomitans CFCS. Monocytes were the only cells analyzed to express Fas ligand (FasL) constitutively, and this was further up‐regulated in response to A. actinomycetemcomitans CFCS, while T cells expressed FasL only after this stimulation. Depletion of monocytes prior to stimulation with A. actinomycetemcomitans CFCS led to a marked decline in apoptosis. Blocking of Fas–FasL interactions with anti‐Fas monoclonal antibody or Fas:Fc fusion protein lead to a significant decline, but not abolition, of T‐cell apoptosis. Nearly all T cells expressed Bcl‐2 at the outset of culture, and Bcl‐2 expression declined in T cells stimulated with A. actinomycetemcomitans CFCS. Collectively, these data provide evidence for the induction of T‐cell apoptosis by A. actinomycetemcomitans via the Fas‐mediated pathway, involving caspase‐3 and Bcl‐2. Moreover, this apoptotic response was dependent on the presence of monocytes.
Similarity of the oral microbiota of pre‐school children with that of their caregivers in a population‐based study
Authors: Tanner A. C. R. , Milgrom P. M. , Kent R. , Mokeem S. A. , Page R. C. , Liao S. I. A. , Riedy C. A. , Bruss J. B.
Published: March 2003

This study evaluated the similarity between the oral microbiota of young children and that of their adult caregivers. Oral samples from children (174 dentate and 18 pre‐dentate) aged 6–36 months and their caregivers in Saipan were assayed using a DNA probe assay. Many species including Streptococcus mutans, Streptococcus sobrinus, Actinomyces species, Campylobacter rectus, Fusobacterium nucleatum, Prevotella intermedia, and Porphyromonas gingivalis were detected in dentate and pre‐dentate children, whereas Bacteroides forsythus was detected only in dentate children. A higher percentage of children were positive for the detection of an individual species if the caregiver was also positive. There were significant relative risks of species detection between dentate children and their caregivers. By logistic regression, there were significant positive associations between species detection in caregiver and in child, but not between species detection and child age or maternal education level. In conclusion, dental pathogens were detected in young, including pre‐dentate, children. The microbial profiles of children were strongly associated with the microbiota of their caregivers.
Asthma and allergy among schoolchildren in a mountainous, dry, non‐polluted area in Norway
Authors: Njå Frode , Røksund Ola Drange , Svidal Bjørn , Carlsen Kai‐håkon
Published: March 2003

The aim of this study was to assess prevalence of asthma and allergy in the non‐polluted mountain area of Upper Hallingdal, Norway. All schoolchildren (7–16 years) who in a previous questionnaire survey (n = 1177) reported ‘sometime’ asthma were enrolled in group I (n = 80), the 59 who reported asthma‐like symptoms in the past 12 months formed group II, and 77 of the healthy controls were randomly selected as group III. All 216 children underwent clinical examination, skin prick test, spirometry, bronchial provocation (PD20 metacholine) and treadmill exercise test. Subsequently they were reclassified as (1) healthy, never had asthma or symptoms, (2) symptoms not confirmed as asthma, (3) previous asthma, now healthy, (4) current asthma. Lifetime asthma prevalence was 10.2%. Based upon clinical examination, the specificity and sensitivity of the questionnaire for asthma diagnosis were 0.88 and 0.74, respectively. Forced vital capacity was significantly higher among the asthmatics (group 4 versus 1), whereas forced expiratory volume in one second (FEV1) and forced expiratory flow at 50% of vital capacity were similar in all groups. More than 10% reduction in FEV1 following treadmill‐run was found in 20% of children. Children with current asthma compared to controls had significantly; lower mean values of PD20 (9.1 versus 16.5 µmol), higher eosinophil cationic protein (13.4 versus 7.7 µmol) and more frequent sensitization to animal dander (56% versus 10%). In conclusion, despite a favorable climate, little mite sensitization and low outdoor pollution, asthma prevalence was surprisingly high in Upper Hallingdal. Sensitization to animal dander was the most important contributing factor for current asthma.
Inhaled corticosteroids during and after respiratory syncytial virus‐bronchiolitis may decrease subsequent asthma
Authors: Kajosaari Merja , Syvänen Pirkko , Förars Merit , Juntunen‐Backman Kaisu
Published: March 2003

Respiratory syncytial virus (RSV) bronchiolitis in infancy can lead to bronchial hyper‐reactivity or recurrent obstructive bronchitis. The aim of the present study was to determine whether the type of treatment has an influence on respiratory status after RSV bronchiolitis. The study involved 117 infants (mean age 2.6 months), who needed hospital treatment because of RSV bronchiolitis. The patients were divided randomly into three groups. All received the same symptomatic treatment. Group I children received symptomatic treatment only, group II children were treated for 7 days with inhaled budesonide, 500 µg three times per day, administered via a nebulizer. Group III children received nebulized budesonide, 500 µg twice per day for two months. Follow‐up consisted of out‐patient check‐ups 2 and 6 months after the infection, and telephone contact two years after the infection. Statistically significant differences were seen between the groups. In group I 37% of the children had asthma, in group II 18%, and in group III 12%. According to the present study it seems that inhaled corticosteroid treatment during and after the acute phase of infant RSV bronchiolitis may have a beneficial effect on subsequent bronchial wheezing tendency.
Wheezing following lower respiratory tract infections with respiratory syncytial virus and influenza A in infancy
Authors: Eriksson Margareta , Bennet Rutger , Nilsson Anna
Published: March 2003

We examined the incidence of subsequent wheezing in 292 children, hospitalized for influenza A or respiratory syncytial virus (RSV) lower respiratory tract infection, during two consecutive seasons (November–December, 1993 and March–April, 1995). Questionnaires concerning episodes of wheezing and known risk factors for wheezy bronchitis were mailed to parents 1 year after hospitalization. Sixty per cent of parents reported two or more episodes of wheezing following either influenza A or RSV. Hospitalization as a result of wheezing was necessary in 15% of the patients. The severity of the primary infection, as indicated by the need for treatment in the intensive care unit (ICU), was correlated with later wheezing. No additional significant risk factors predicting later wheezing could be identified.
Low‐dose cyclosporin A microemulsion in children with severe atopic dermatitis: Clinical and immunological effects
Authors: Bunikowski Rita , Staab Doris , Kussebi Fatima , Bräutigam Matthias , Weidinger Gottfried , Renz Harald , Wahn Ulrich
Published: March 2003

Cyclosporin A (CsA) is an effective and well‐tolerated treatment for severe childhood atopic dermatitis (AD). By starting at a low dose, the therapeutic safety should be further increased. The aim of this study was to evaluate low‐dose CsA in childhood AD with respect to clinical outcome and modulation of T‐cell dysregulation. In an open prospective study, 10 children (age: 22–106 months) with severe AD (mean objective SCORAD score > 40 on two baseline measurements at a minimum interval of 2 weeks) were treated with CsA solution for 8 weeks. All patients received a starting dose of 2.5 mg/kg/day, which was increased stepwise in non‐responders to a maximum of dose of 5 mg/kg/day. Disease activity was monitored using the SCORAD index. The frequency of cytokine‐producing peripheral blood T lymphocytes was analyzed by intracellular cytokine staining, and T‐cell numbers were measured by fluorescence‐activated cell sorter (FACS) analysis. Twenty healthy age‐matched children were included as controls for the immunological data. Nine of the 10 patients had a SCORAD reduction of at least 35%. In seven patients this was achieved with low‐dose CsA at 2.5 mg/kg/day (n = 4) and 3.5 mg kg/day (n = 3). Seven of the nine responders experienced no relapse within the 4‐week follow‐up period. At baseline the percentage of interleukin‐4 (IL‐4), IL‐13, and human leucocyte antigen (HLA)‐DR‐positive CD3+ cells was higher in the patient group than in the controls. After CsA treatment there was a significant reduction in interferon‐γ (IFN‐γ), IL‐2, IL‐4, IL‐13, and HLA‐DR‐positive CD3+ cells. Hence, in severe pediatric AD, CsA microemulsion, when started at a low dose (2.5 mg/kg/day), improves clinical measures of disease, reduces T‐lymphocyte cytokine production, and regulates T‐cell activation.
Is early BCG vaccination associated with less atopic disease? An epidemiological study in German preschool children with different ethnic backgrounds
Authors: Grüber Christoph , Meinlschmidt Gerhard , Bergmann Renate , Wahn Ulrich , Stark Klaus
Published: March 2003

We investigated the association of bacille Calmette‐Guérin (BCG) vaccination and atopic manifestations among children. Because many children in the study area were from minority ethnic groups, the effect of ethnicity on disease prevalence was also analyzed. A mandatory health survey included all preschool children from Berlin in 1994. Trained medical personnel asked parents whether their child had ever had a diagnosis of atopic dermatitis (AD), bronchial asthma (BA), and hay fever (HF) or symptoms suggestive of these conditions. BCG‐vaccination status was recorded from official vaccination documents. Ethnicity of the child was defined by maternal citizenship. We included 38 808 children in our study (20 813 children from former west Berlin), on average aged 6 years. The proportion of children with a foreign family background was 2.1% in East Berlin and 27.5% in West Berlin. BCG vaccination was more common in East Berlin than in West Berlin (94.2% vs. 16.5%) and in West Berlin more common among children with a foreign family background compared with Germans (25.3% vs. 13.2%). The adjusted odds ratio (95% CI) for BA was 0.85 (0.71–1.00) for BCG‐vaccinated individuals. BCG vaccination was not significantly associated with AD or HF. Among non‐German children, the odds ratios were 0.35 (0.30–0.42) for AD, 0.58 (0.48–0.70) for BA, and 0.72 (0.54–0.92) for HF. The OR for AD among children living in eastern Berlin was 1.19 (1.04–1.36), no significant regional differences were found for BA or HF. This study demonstrated a weak protective effect of BCG vaccination against asthma but a much stronger protective effect of non‐German ethnicity against atopic manifestations among preschool children from Germany.
Low frequency of CD4+, but not CD8+, T cells expressing interferon‐γ is related to cow's milk allergy in infancy
Authors: Österlund Pamela , Suomalainen Hanna
Published: March 2003

Low interferon‐γ (IFN‐γ) and tumor necrosis factor‐α (TNF‐α) production in peripheral blood mononuclear cells (PBMC) from patients with atopic dermatitis and food allergy have been reported previously. However, it remains unclear whether the weak cytokine production is caused by the imbalance of specific T‐cell subsets or by dysregulation of T‐cell function. In the present study we investigated the intracellular expression of these cytokines at a single‐cell level to clarify the background of the disruption. Twelve of 27 breast‐fed infants (0.1–8.8 months of age) had challenge‐proven cow's milk allergy (CMA), and 15 infants were studied as a healthy control group. PBMC were stimulated with phorbol 12‐myristate 13‐acetate (PMA) and ionomycin. The frequencies of the cells expressing intracellular IL‐4, IFN‐γ, and TNF‐α were assessed using flow cytometry. In addition, at this time‐point leucocyte subsets from the milk of mothers of these infants were evaluated using light microscopy. A lower number of CD8+ T cells and the defective capability of CD4+ T cells to express IFN‐γ in infant's peripheral blood co‐existed with a lower number of macrophages in their mother's milk.
Quantitation of allograft fibrosis and chronic allograft nephropathy
Authors: Grimm Paul C. , Nickerson Peter , Gough Jim , McKenna Rachel , Jeffery John , Birk Patricia , Rush David N.
Published: March 2003

Abstract:Despite improvements in the prevention and treatment of acute renal allograft rejection, the long‐term survival of renal transplants has not increased. Immunologic and non‐immunologic factors contribute to the gradual deterioration of graft function and to the histologic lesion characterized by vascular and interstitial fibrosis (‘chronic rejection’). Quantitation of this process has been attempted using various invasive and non‐invasive methods. These methods, performed at different times post‐transplant, are reviewed in this article. In particular, pathology scoring systems and the potential of using computerized image analysis of biopsy material are discussed.
Intensive care management after pediatric liver transplantation: A single‐center experience
Authors: Ganschow R. , Nolkemper D. , Helmke K. , Harps E. , Commentz J. C. , Broering D. C. , Pothmann W. , Rogiers X. , Hellwege H. H. , Burdelski M.
Published: March 2003

Abstract:A retrospective study was conducted to determine the significance of intensive care management on outcome after liver transplantation (LTx) in children. Of 195 transplants performed in 162 children, factors affecting morbidity and mortality were documented during the post‐operative intensive care unit (ICU) stay. To assess the gain in experience of ICU management, we compared mean ventilation time and stay in the ICU as well as mortality, incidence of surgical complications, infections, and rejection episodes, during three different time‐periods (October 1991–August 1994, September 1994–July 1996, and August 1996–February 1998). The time spent by patients in the ICU (9.7 days vs. 7.9 days vs. 4.7 days, p < 0.001) and time on ventilation (5.2 days vs. 3.1 days vs. 1.2 days, p < 0.001) were significantly reduced over the duration of the study. The overall mortality was 18.0% (n = 30) and 76.7% (n = 23) of these deaths occured during the early post‐operative period in the ICU. The incidence of severe surgical complications decreased significantly over time, and the application of intra‐operative Doppler ultrasound since 1994 led to detection of 27 correctable vascular complications. The overall incidence of acute cellular rejection episodes in our center was 64.1%: 43.5% of the infectious episodes occured in the ICU (bacterial 70.2%, viral 12.3%, and fungal 17.5%). The main side‐effect from immunosuppressive drugs was arterial hypertension in 29% of the patients. We conclude that our efforts to improve intensive care management and monitoring were the key elements in reducing morbidity and mortality after pediatric LTx.
Primary tacrolimus (FK506) therapy and the long‐term risk of post‐transplant lymphoproliferative disease in pediatric liver transplant recipients
Authors: Cacciarelli Thomas V. , Reyes Jorge , Jaffe Ronald , Mazariegos George V. , Jain Ashok , Fung John J. , Green Michael
Published: March 2003

Abstract: While the overall incidence of post‐transplant lymphoproliferative disease (PTLD) in pediatric liver transplant recipients has been reported to be 4–11%, the long‐term risk of PTLD associated with primary tacrolimus therapy is unknown. Therefore, in order to determine the incidence and long‐term risk of PTLD, the present study examined 131 pediatric recipients who underwent liver transplantation (LTx) between October 1989 and December 1991 and received primary tacrolimus therapy. This cohort of children was evaluated over an extended time‐period (until December 31 1996) with a mean follow‐up of 6.3 yr. Actuarial Kaplan–Meier analysis was utilized to determine the risk of PTLD over time. The overall incidence of PTLD was 13% (17/131) with an average age of 4.3 ± 0.75 yr at diagnosis. Pretransplant Epstein–Barr virus (EBV) serologies were negative in 82%, positive in 12%, and not available in 6% of the patients. The median time to diagnosis of PTLD post‐Tx was 11.9 months (mean 16.4 ± 3.9, range 1.7–63.0 months). Mean tacrolimus dose and plasma trough level (as evaluated by enzyme‐linked immunosorbent assay [ELISA]) at the time of diagnosis was 0.32 ± 0.06 mg/kg/day and 1.3 ± 0.3 ng/mL, respectively. The cumulative long‐term risk of PTLD was found to increase over time: 3% at 6 months, 8% at 1 yr, 12% at 2 yr, 14% at 3 yr, and 15% at 4 and 5 yr. Mortality from PTLD was 12% (two of 17 patients). Primary tacrolimus use in pediatric LTx has a long‐term risk of PTLD approaching 15%, with the majority of episodes (78%) occurring in the first 2 yr, suggesting that intense EBV surveillance should occur early post‐transplantation.
Mycophenolate mofetil in pediatric heart transplant recipients: A single‐center experience
Authors: Dipchand Anne I. , Benson Lee , McCrindle Brian W. , Coles John , West Lori
Published: March 2003

Abstract:Mycophenolate mofetil (MMF) is emerging as an effective agent for the treatment of both established rejection and primary rejection prophylaxis in solid‐organ transplantation (Tx). However, little data is available on the use of MMF in the pediatric population. We therefore report on our experience with MMF in 21 pediatric heart transplant recipients. Data were obtained by retrospective chart review. Median age at time of review was 12.3 yr (range 11 months to 16.9 yr). Median age at Tx was 10.7 yr (range 55 days to 16.7 yr). MMF was started at a median of 4.3 months after Tx (range 1 day to 4.5 yr). At the time of MMF institution, all patients were concurrently on prednisone and azathioprine; 20 of these patients were also undergoing treatment with tacrolimus (median dose 0.18 mg/kg, range 0.03–0.64 mg/kg) and one with cyclo‐sporin A (10 mg/kg). Azathioprine was discontinued at the time of commencing MMF. The average MMF dose was 40 ± 14 mg/kg. The rationale for switching to MMF included rejection (International Society for Heart and Lung Transplantation [ISHLT] 3A/B), 66%; inability to wean steroids, 14%; ABO blood group donor–recipient mismatch, 10%; coronary artery disease (CAD), 5%; and side‐effects of immuno‐suppression, 5%. Of the patients switched for rejection, 93% demonstrated resolved or improving rejection. Both ABO donor–recipient mismatch patients were started on tacrolimus/MMF as primary therapy and had no significant episodes of rejection. Two patients had rejection classified as unchanged (one with CAD, one treated with addition of sirolimus prior to improvement). Corticosteroids were successfully discontinued in 28% of patients, and 20% are currently on a reduced dose. Fourteen per cent developed significant rejection while attempting to reduce the steroid dose. Steroid reduction has not yet been attempted in 38% of patients. The following side‐effects were reported in 38% of the patients: diarrhea, 10%; gastrointestinal discomfort, 20%; and leukopenia, 20%. Dose reduction or temporary discontinuation was required in 63% of the patients who experienced side‐effects (24% of the total number of patients). Opportun‐istic infections developed in 10% (cryptococcus, cytomegalovirus). Hence, MMF appears to be effective for treatment of rejection in the pediatric heart transplant population and has an acceptable side‐effect profile. In addition, it may have a role in primary rejection prophylaxis and may facilitate a reduced steroid dosage or a steroid‐free immunosuppression regimen.
Factors limiting the rate of living‐related kidney donation to children in an inner city setting
Authors: Hidalgo Guillermo , Tejani Cena , Clayton Rosita , Clements Peggy , Distant Dale , Vyas Shefali , Baqi Noosha , Singh Anup
Published: March 2003

Abstract:A recent review of our center experience revealed that only 38% of our pediatric renal transplants come from living‐related donors (LRD), which is 11% lower than the national average. The present study was designed to identify factors that limit the availability of LRD in our population pool. Retrospective chart reviews and subsequent telephone interviews were conducted with parents of all children who received renal replacement therapy (RRT) at our institution from 1990 to 1999. The availability of parents and their willingness to donate a kidney were noted. Self‐reported willingness was defined as the verbal expression of a desire to donate. Firm willingness was defined as the completion of the steps necessary for donation, unless excluded by the medical team. Factors that may impact the ability to donate, such as donor age, ethnicity, religion, educational attainment, employment, and presence of other siblings younger than 18 yr of age, were evaluated. Statistical analyses were performed using the Student'st‐test and chi‐square analysis. Significant results were entered into a single‐step multiple regression analysis. Sixty children were identified with RRT, of whom 60% were Blacks, 30% Hispanics, 7% Caucasians, and 3% Asian. Fifty‐five mothers were available for interview. Forty‐four mothers reported a desire to donate, nine were unwilling to donate, and two were undecided. However, only 35 attended for screening. Only 30 fathers were available and, of these, 27 reported willingness to donate, yet only 20 attended for screening. Seventy‐four per cent (26 out of 35) of mothers screened and 55% (11 out of 20) of fathers screened were medically unsuitable for kidney donation. Nineteen potential donors had hypertension, diabetes and/or obesity, seven had renal disease, four had anemia, two had hepatitis C, and five had other conditions. Expressed unwillingness to donate was associated with a greater number of children (3.1 compared to 1.5 children in addition to the child with end‐stage renal disease [ESRD]) (odds ratio 2.91, p < 0.05) and employment (26.3% vs. 4.0%, p < 0.05) (odds ratio 31.2, p = 0.05). Comparing mothers who were firmly willing to donate with mothers who did not complete screening and evaluation, unwilling mothers had, likewise, a greater number of children (2.9 vs. 1.2 in addition to the child with ESRD) (odds ratio 3.23, p < 0.01) and a greater number of years of education (12.4 vs. 10.4) (odds ratio 2.14, p < 0.05). Hence, the availability of living kidney donors for our inner city children is severely limited by a high rate of single parenthood and a high rate of comorbid conditions in the parental donor pool. Furthermore, there is a diminished capacity of the available parent, particularly the mother, to donate as she tends to have numerous other dependents.
Necrotizing fasciitis following liver and small intestine transplantation
Authors: Kobayashi Shogo , Kato Tomoaki , Nishida Seigo , Buttrago Efren , Mittal Naveen , Thompson John , Tzakis Andreas G.
Published: March 2003

Abstract: Necrotizing fasciitis is a rare, subcutaneous infection. It can occur in patients after solid‐organ transplantation. We herein report two patients who developed necrotizing fasciitis following combined liver and small intestine transplantation. The first patient experienced this infection 4 yr after transplantation and 1 yr after the closure of the ileostomy. The second patient suffered from necrotizing fasciitis 2 days after the transplant. Both cases were diagnosed on the physical findings, culture of subcutaneous lavage, and the computed tomography findings. The site of entrance of the organism was not clear in either case. Both patients had a fulminant course and died within 1 week from the onset, despite aggressive surgical intervention. Therefore, necrotizing fasciitis has to be recognized as a potential complication of intestinal transplantation.
Optimal immunosuppression in teenagers
Authors: Kelly Deirdre A.
Published: March 2003

Abstract:Adolescence is a difficult time for transplant recipients, who need to cope with the challenges of becoming independent from their parents, as well as taking responsibility for their own behavior and medication. They need to balance their developing sexuality with a body image which may be affected by the side‐effects of immunosuppression. It is now anticipated that more than 80% of children will survive their transplant to become teenagers and adults, and it is therefore important to ensure that immunosuppressive medication is acceptable, convenient for drug level monitoring and free of significant long‐term side‐effects.
Measles: A rare communicable disease in a child with renal transplantation
Authors: Kalman Süleyman , Bakkaloglu Sevcan A. , Özkaya Ozan , Buyan Necla , Söylemezoglu Oguz
Published: March 2003

Abstract: Measles is a rare communicable disease which may be fatal in renal transplant patients. Herein we present a patient with renal transplantation who had measles and who subsequently developed subacute measles encephalitis 4 months later. We recommend all children with chronic renal failure be vaccinated against measles before transplantation.
Hepatic insufficiency and liver transplantation in a patient with COACH syndrome
Authors: Herzog D. , Martin S. , Yandza T. , Alvarez F.
Published: March 2003

Abstract:An 8‐yr‐old‐patient was diagnosed with COACH syndrome at the moment of her first bleeding episode from esophageal varices. Investigations revealed biliary cirrhosis as the cause of portal hypertension, no visible kidney cyst or impairment of renal function, cerebellar dysplasia with non‐disabling ataxia, and minimal mental retardation. By the age of 12 yr she had developed liver insufficiency and, after a challenging discussion, underwent a liver transplantation. She subsequently developed an abdominal aspergillosis, which required several abdominal explorations and splenectomy as well as 6 months of therapy with liposomal amphotericin B, but survived and in long‐term follow‐up is in good health, with completed puberty, and has finished school.
Epstein–Barr virus and post‐transplant lymphoproliferative disease
Authors: Holmes R. D. , Sokol R. J.
Published: March 2003

Abstract:There is convincing evidence that Epstein–Barr virus (EBV) is associated with post‐transplant lymphoproliferative disease (PTLD). Primary EBV infection following transplantation occurs in as many as 90% of cases of PTLD in children and pretransplant EBV seronegativity is a recognized risk factor for developing PTLD. Other risk factors include young age at the time of transplant, the type of transplant that the recipient receives and the type and intensity of immunosuppression. The clinical presentation is often nonspecific and tissue biopsy is necessary to establish the diagnosis. There appears to be a correlation between PTLD and EBV viral load measured by polymerase chain reaction (PCR) of the peripheral blood and quantitative PCR may be a useful guide in the management of PTLD. Antiviral drugs and cytomegalovirus‐immunoglobulin G may have a role in preventing PTLD. Because PTLD results from functional over‐immunosuppression, the initial treatment is reduction of immunosuppression. Antiviral agents, interferon, immuno‐based monoclonal therapy, cell‐based therapy and chemotherapy also have a potential role in treating this disorder. At the present time there is no standardized approach to the evaluation and treatment of PTLD.
Long‐term outcome after liver transplantation in children
Authors: Bucuvalas John C. , Ryckman Frederick C.
Published: March 2003

Abstract:Children (defined as under 18 yr of age) account for approximately 12.5% of all liver transplants in the United States. Even though the annual number of liver transplantation procedures remains relatively constant, the population of long‐term survivors of liver transplantation has grown. Presently, the population of long‐term survivors of liver transplantation is 10‐fold greater then the number of transplantations carried out each year. For long‐term survivors of liver transplantation, the goal is to maintain graft function and wellness while decreasing the morbidity associated with long‐term immunosuppression. The primary diagnosis leading to liver transplantation in children do not recur in the allograft. Consequently, many of the complications of liver transplantation, both early and long term, relate to the need for immunosuppression. Children may be at increased risk to develop significant end‐organ damage as a result of increased serum lipid levels, elevated blood pressure, altered glucose metabolism, decreased renal function, cancer, and diminished bone accretion that occur as a result of immunosuppressive therapy or complications of therapy. As survival rates have increased, health care providers have begun to assess health‐related quality of life. We will review our current knowledge of long‐term outcome following pediatric liver transplantation in children.
Arterioportal fistulae following segmental liver transplantation in a child
Authors: Mieles L. A. , Waldman D. , Orloff M. S.
Published: March 2003

Abstract:We report a case of arterio‐portal fistulae in a 12‐month‐old‐child following a segmental liver transplantation. The fistula, probably the result of mass ligature of a vascular pedicle during back table allograft reduction, is to our knowledge the first such case reported. Diagnosed on the third post‐operative day, the fistula was successfully managed with transcatheter coil embolization. The child is well and asymptomatic, 33 months after transplantation. In addition to those seen in whole organ transplantation, there are a few complications specifically related to segmental transplantation. These complications, although infrequent, are a direct consequence of the back table liver partition, as in the case herein reported.
No relation between drought stress and ethylene production in Norway spruce
Authors: Eklund Leif , Cienciala Emil , Hällgren Jan‐Erik
Published: March 2003

The relationship between water availability and ethylene production was studied in 24‐year‐old trees of Norway spruce [Picea abies (L.) Karst.] growing on experimental plots with different water availability. Ethylene and oxygen were collected from the cambial/xylem region and heartwood in the stem using non‐destructive sampling methods. Xylem sap flow was measured in stems using a heat‐balance technique. Pre‐dawn water potential of shoots was used to assess the water status of the trees. Growth was calculated from increments in stem basal area. The highest ethylene concentrations were found in irrigated trees that also, as compared to the other treatments, showed the most rapid flow rate of sap, the highest pre‐dawn water potential, and the most rapid growth. By contrast, the lowest ethylene concentrations were measured in trees to which artificial drought was induced. Such trees also showed the lowest water transport, lowest water potential and relatively slow growth. Thus, no signs of drought‐induced ethylene production were found in this study, contrary to the general contention of a positive relation between drought stress and ethylene production.
Oxidation of hydroxycinnamic acid and hydroxycinnamyl alcohol derivatives by laccase and peroxidase. Interactions among p‐hydroxyphenyl, guaiacyl and syringyl groups during the oxidation reactions
Authors: Takahama Umeo
Published: March 2003

Fungal laccase oxidized derivatives of hydroxycinnamic acid. The rates decreased in the order sinapic acid > ferulic acid ≥p‐coumaric acid. The laccase oxidized sinapyl alcohol faster than coniferyl alcohol. The rates of oxidation of the hydroxycinnamic acid derivatives by an isoenzyme of peroxidase from horseradish decreased in the order p‐coumaric acid > ferulic acid ≥ sinapic acid. The peroxidase oxidized coniferyl alcohol much faster than sinapyl alcohol. The laccase and the peroxidase predominantly oxidized (a) ferulic acid in a reaction mixture that contained p‐coumaric acid and ferulic acid, (b) sinapic acid in a mixture of p‐coumaric acid plus sinapic acid, and (c) sinapic acid in a mixture of ferulic acid plus sinapic acid. In a reaction mixture that contained both coniferyl and sinapyl alcohols, both fungal laccase and horseradish peroxidase predominantly oxidized sinapyl alcohol. From these results, it is concluded (1) that the p‐hydroxyphenyl radical can oxidize guaiacyl and syringyl groups and produce their radicals and (2) that the guaiacyl radical can oxidize the syringyl group under formation of its radical; and that (3) in both cases the reverse reactions are very slow.
Boron controls suspensor development in embryogenic cultures of Larix decidua
Authors: Behrendt Ulrike , Zoglauer Kurt
Published: March 2003

Suspensor formation in somatic embryos of Larix decidua Mill. was. studied in relation to its dependence on nutritional factors of the culture medium. Protoplasts exhibiting embryogenic competence were prepared from an embryogenic suspension culture, immobilized in Ca‐alginate and cultured in liquid media. Developmental patterns showed qualitative differences in the two basic media used. In one medium, containing 100 μM boric and, compact colonies developed, most of which displayed formation of polar suspensors after 3 to 4 weeks. In contrast, suspensor development never occurred in the other medium, containing 10 μM borate, yet colonies of loosely connected cytoplasmically dense cells were regenerated without loss of embryogenic competence. Detailed examination of the constituents of the two media led to the conclusion that suspensor development is dependent on boron concentration: below 35 μM boron, suspensor formation is blocked completely, whereas with an increase up to 1 μM boron there is a progressively faster development of suspensor‐bearing embryos.
Cuttings of a tobacco mutant, rae, undergo cell divisions but do not initiate adventitious roots in response to exogenous auxin
Authors: Lund Steven T. , Smith Alan G. , Hackett Wesley P.
Published: March 2003

Numerous studies have shown that auxin induces adventitious root initiation in stem explants from a variety of species, including tobacco. A dominant, monogenic mutation previously identified in tobacco (Nicotiana tabacum cv. Xanthii), rac, confers tenfold auxin resistance to mesophyll‐derived cell suspensions and an impaired primary root development phenotype to seedlings. Results presented here demonstrate that adventitious root formation does not occur when heterozygous and homozygous rac stem cuttings are treated in vitro with indole‐3‐butyric acid (IBA) concentrations ranging from 0.5 μM to 500 μM. Histological analysis showed that some phloem parenchyma or inner cortical parenchyma cells in wild‐type stem cuttings undergo adventitious root morphogenesis when they are treated with 5 μM IBA. The same cell types in heterozygous and homozygous rac stem cuttings undergo mitoses in response to auxin, but never form adventitious root meristems. The lack of adventitious root initiation in rac stem cuttings is phenotypically distinct from the aberrant primary root development in rac seedlings. The rac mutation appears to block an essential process for auxin induction of adventitious root initiation but not cell division in phloem parenchyma or inner cortical parenchyma cells. Comparisons of rac heterozygous and homozygous seedling primary root length and callus formation in response to auxin in stem cuttings indicate that rac copy number is correlated to the degree of expression of these two phenotypes.
Photocontrol of somatic embryogenesis and polyamine content in Araujia sericifera petals
Authors: Torné José M. , Moysset Luisa , Claparols Inmaculada , Simón Esther
Published: March 2003

The effects of photoperiod and end‐of‐day phytochrome control on somatic embryogenesis and polyamine (PA) content in Araujia sericifera petals have been studied. Petals from immature flowers were cultured under 16‐ and 8‐h photoperiods. Far red (FR), red (R) and FR followed by R light treatments were applied at the end of the photoperiods for three weeks. The number of somatic embryos, callus weight and the levels of free and bound PAs in the cultured petal explants were determined 40 days after the beginning of light treatments. Long day (LD) promoted somatic embryogenesis but did not have any significant effect on PA content. Short day (SD) reduced somatic embryogenesis and enhanced total PAs, mainly in the form of bound spermidine. End‐of‐day FR treatment increased PA content and inhibited somatic embryogensis under LD but had no significant effect under SD. This effect of FR on PA levels was cancelled by R and was independent of the presence of silver thiosulphate in the medium. End‐of‐day R treatment reduced the total PA content under SD. However, end‐of‐day R increased or reduced somatic embryogenesis under SD depending on the presence or absence of silver in the medium. The results suggest a photoperiodic control of somatic embryogenesis and PA content in A. sericifera. The effects of end‐of‐day R and FR treatments depend on the length of the photoperiod. This finding and the FR/R photoreversibility of end‐of‐day treatments indicate that phytochrome may be involved in both somatic embryogenesis and accumulation of PA.
Culture on sugar medium enhances photosynthetic capacity and high light resistance of plantlets grown in vitro
Authors: Tichá I. , Čáp F. , Pacovská D. , Hofman P. , Haisel D. , Čapková V. , Schäfer C.
Published: March 2003

The significance of photosynthetic photon flux (PPF) and sugar feeding for the production of plants in vitro is only poorly understood. Nicotiana tabacum L. plantlets were grown photoautotrophically and photomixotrophically (3% sucrose) at two different PPFs (60 µmol m−2 s−1 and 200 µmol m−2 s−1) to investigate the effect of these culture parameters on photosynthetic performance and growth. Photomixotrophically‐grown plantlets showed an increase in carbohydrate content, mainly in glucose and fructose. Plant growth, dry matter accumulation and total leaf area were higher under photomixotrophic than photoautotrophic conditions. Not only biomass formation but also photosynthesis was positively affected by exogenous sucrose; the chlorophyll (Chl) content and the light‐saturated rate of photosynthetic oxygen evolution were higher in photomixotrophic plantlets. Photoinhibition occurred in plantlets that were grown photoautotrophically at the higher PPF. It became apparent as a loss in Chl content and photochemical efficiency. Photoinhibited plantlets showed a decrease in the D2/LHCII and CP47/LHCII ratios, suggesting a preferential loss of proteins from the photosystem II (PSII) core. The increased content of xanthophyll cycle pigments in photoinhibited plantlets indicated that also protective mechanisms were activated. Photomixotrophic growth of the plantlets prevented the occurrence of photoinhibitory symptoms. Therefore, we conclude that culture on sugar medium increases not only the photosynthetic potential but also the high light resistance of plantlets grown in vitro.
Apoplastic and membrane‐associated Ca2+ in leaves and roots as affected by boron deficiency
Authors: Mühling Karl Hermann , Wimmer Monika , Goldbach Heiner E.
Published: March 2003

A combination of fluorescein‐isothiocyanate (FITC), coumarin‐benzothiazol (BTC), and chlorotetracycline (CTC) fluorescence was used to simultaneously monitor apoplastic pH, apoplastic free Ca2+, and plasma membrane‐bound Ca2+. As early boron deficiency reactions supposedly include alterations of plasma membrane‐bound transport processes besides rapid effects on cell wall physical properties, the corresponding changes were followed in leaves and roots of Vicia faba L. cv. Troy.

Boron deficiency did not alter the apoplastic pH, but it reduced plasma membrane‐bound Ca2+ in roots at 4 h and leaves at 3 days after starting the deficiency treatment. The decrease in plasma membrane‐bound Ca2+ coincided with an increase in apoplastic free Ca2+ and K+, and occurred before the first visible symptoms were noticed.

It is proposed that less Ca2+ is bound to the plasma membrane due to a reduction of specific Ca2+‐binding sites (borate esters with vic‐diols or polyhydroxy‐carboxylates) before plasma membrane integrity deteriorates.
Influence of senescence and of carbohydrate levels on the pattern of leaf proteases in purple nutsedge (Cyperus rotundus)
Authors: Fischer Andreas , Brouquisse Renaud , Raymond Philippe
Published: March 2003

Cyperus rotundus L. is a monocotyledonous perennial weed, which forms large numbers of tubers during its vegetative growth. Since these tubers represent major sinks, source/sink interactions are more complex, and leaf senescence and proteolytic processes in this species may be different from the situation in the well‐investigated annual crop plants characterized by monocarpic senescence. Judged by native PAGE and by inhibitor studies, three different aminopeptidases, one iminopeptidase, two or more carboxypeptidases and two or more different endopeptidases were present in mature green leaves. Exo‐ and endoproteolytic activities increased during the senescence of excised leaf segments. A marked change was observed in the endopeptidase pattern, since a cysteine proteinase activity was strongly induced during senescence of the segments. This endopeptidase was also found in naturally senescing leaves and may, therefore, participate in nitrogen salvage from these organs. An increase of different protease activities was demonstrated in leaf segments of C. rotundus in the presence of high carbohydrate levels. The mechanisms involved, and the importance of this phenomenon for the interaction between source/sink relations and senescence, remain to be demonstrated.