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Biomedical subjects

C Peters

Publications and source records attributed to C Peters.

At least 271 records · Page 15Linked to original sources
PubMedDate not supplied

Transmission of Ebola virus (Zaire strain) to uninfected control monkeys in a biocontainment laboratory.

Secondary transmission of Ebola virus infection in humans is known to be caused by direct contact with infected patients or body fluids. We report transmission of Ebola virus (Zaire strain) to two of three control rhesus monkeys (Macaca mulatta) that did not have direct contact with experimentally inoculated monkeys held in the same room. The two control monkeys died from Ebola virus infections at 10 and 11 days after the last experimentally inoculated monkey had died. The most likely route of infection of the control monkeys was aerosol, oral or conjunctival exposure to virus-laden droplets secreted or excreted from the experimentally inoculated monkeys. These observations suggest approaches to the study of routes of transmission to and among humans.

Aerosols↗
PubMedDate not supplied

Hematopoietic stem cell transplantation for mucopolysaccharidoses and leukodystrophies.

The only effective treatment for selected metabolic diseases is a successful allogeneic hematopoietic stem cell transplantation (HCT). Best results with HCT are obtained when performed early in the course of the disease. Hence, timely identification and referral are critical. Also, early identification of affected patients during the newborn period via screening may be invaluable, particularly for the infantile onset rapidly progressive forms of diseases. Rapid availability of a donor graft is often crucial for these patients. Preliminary experience suggests that results after umbilical cord blood (UCB) transplant may be comparable to those after marrow transplants. UCB grafts have certain benefits of rapid availability and even reduced risk of GvHD. Hence, UCB transplant represents an alternative to marrow HCT. Related haploidentical HCT, possibly with very high doses of CD34+ cells, may also represent an option. However, expertise has been developed in very few transplant centers and no large reports are available of its use for patients with inherited metabolic diseases.

Adrenoleukodystrophy↗
PubMedDate not supplied

[Autologous peripheral stem cell transplantation in children].

19 children between 3 and 23 years underwent 79 leukapheres for collection of blood stem cells. In children suffering from acute lymphoblastic leukemia (ALL), Non Hodgkin's Lymphoma (NHL) and Ewing's Sarcoma (ES) we collected 6.87 x 10(4) CFU-GM/kg (range 2,65-21.7), if collections were started with the first platelet rise. In children with peripheral primitive neuroectodermal tumors (PNET) and neuroblastoma (NBL) we gained only 1.20 x 10(4) CFU-GM/kg (range 0.09-2.24). 17 children received high dose chemoradiotherapy and peripheral stem cell +/- bone marrow rescue. 9 suffered from solid tumors, 8 from hematopoietic malignancies. 9 were transfused with peripheral stem cells only, 8 received bone marrow in addition. Time to reach 0.5 x 10(9)/l granulocytes was very short-median 31 days (12-65), in 4 children receiving more than 5 x 10(4) CFU-GM/kg 12 to 13 days, only. On January 31st, 1989 6/17 children are alive in complete remission after a median observation time of 14.5 months (3-26) after autologous stem cell transfusion, one child is alive in "no remission", 7 died with relapse, 3 died because of infections (2 x aspergillosis, 1 x pseudomonas septicemia). The collection of blood derived stem cells by leukaphereses was well tolerated even in very small children and easily repeatable. With optimal timing high stem cell numbers were obtainable, resulting in a very short duration of posttransplant granulocytopenia.

Adolescent↗
PubMedDate not supplied

A single centre experience with allogeneic stem cell transplantation for severe aplastic anaemia in childhood.

BACKGROUND: Severe aplastic anaemia (SAA) is a rare disorder which has a fatal course when allogeneic stem cell transplantation (SCT) or an immunosuppressive regimen is not applied. Stem cell replacement is the only curative approach for these patients but it is limited by the availability of a compatible donor. PATIENTS: Between 1982 and 1993, 18 children (15 boys, 3 girls) with SAA and HLA identical, MLC negative donors underwent SCT in our institution. SAA was preceded by viral infection in 8 patients (3x hepatitis, 1x measles, 1x herpes simplex infection and 3x viral upper respiratory tract infections). It was drug-associated in one and idiopathic in the 9 others. The median age at diagnosis was 9.7 years (range, 2 months to 16 years). Pretreatments included corticosteroids in 11/18 patients, androgens in 4 patients in addition, two had received cyclosporin A (CSA). One patient progressing from Diamond- Blackfan anaemia to SAA had multiple immunosuppressive treatment courses over 7 years before his grand-uncle was identified as donor while 4 patients had no treatment prior to SCT. METHODS: Early SCT (within 90 days after diagnosis) was performed in 9/18 patients and the median interval between diagnosis and SCT was 2.6 months (range, 0.5 to 7 years). The stem cell source was the bone marrow (BM) of a syngeneic twin in 2 patients, the BM (13 patients) or the cord blood (1 patient) of a sibling whilst it was BM from a HLA-phenotypical family donor (1 father, 1 grand-uncle) in two patients. Cyclophosphamide 50 mg/kg on 4 consecutive days was given as preparative regimen to 16 patients but not to the two syngeneic twins. Rejection prophylaxis included total lymphoid irradiation in 5/16 patients while in the other 11 patients donor buffy coat cells were given on days +1 to +4. The syngeneic twins had no need for either approach. Patients received a median number of 3.7 x 10(8)/kg nucleated cells (range, 2.6 to 6.7). Prophylaxis of graft versus host disease (GVHD) was carried out with MTX alone (n = 12), with CSA alone (n = 2) or with both (n = 4). All patients received standard supportive care. RESULTS: The overall survival is 89% at the median observation time of 100 months. The median time to reach 500 granulocytes was 24 days (range, 15 to 40). Median time to become transfusion independent after BMT was 30 days for platelets (range, 2 to 111) and was 28 days for packed red blood cells (range, 6 to 128). Acute GVHD was observed in 10/18 patients and involved only skin in 6 patients, skin and liver or gut in two patients and all 3 organs in another two patients. Seven of 10 patients had grade 1 to 2 a GVHD toxicity, whereas 3 patients experienced grade 3 to 4 acute GVHD. Chronic GVHD developed in 5 patients. Acute transplant related mortality was 5.5%. Cause of death was persisting non engraftment till day +180 after 2 transplant procedures in a boy with previous platelet transfusions from his mother. Late mortality occurred in 2 patients: one chronic GVHD associated haemorrhage 20 months after SCT and one chronic GVHD associated septicaemia 10 years after SCT. CONCLUSION: Although this report reflects patients data accumulated over 15 years, results compare favourably with more recent survival data. Acute and late transplant related toxicity was low in patients undergoing early transplantation with adequate prior supportive care. This data confirms that SCT still should be the first treatment choice if an HLA identical sibling is available.

Anemia, Aplastic↗
PubMedDate not supplied

[Measuring vibrations of transport stress in premature and newborn infants during incubator transport].

BACKGROUND: Despite increasing numbers of centers for perinatology, transportation of newborns and premature infants can not totally be avoided for several obvious reasons. The following investigations were carried out as part of our quality control measures of the established neonatal transportation system, and were aimed on the optimization of a new neonatal transportation equipment resulting in reduction of transportation stress caused by acceleration forces. METHOD: The new system investigated consisted of a Volkswagen type T4 equipped with a Dräger incubator type 5400, which was mounted on a pneumatic patient lift. We measured acceleration forces in three axes (expressed as K-Wert) as well as over a spectrum of frequencies (1-80 Hz). Measurements were taken at different points of the transportation unit during simulated transports driving a predetermined route. After obtaining informed consent of the parents, one actual transport of a newborn was used for an additional point measurement at the newborn's head. RESULTS: The mean K-Wert was decreased by about 50% in the vertical axis between the chassis of the car and the incubator by activating the pneumatic patient lift. Without activating the lift the K-Wert increased by about 20% between the car's chassis and the incubator. The frequency analysis showed resonance effects between the different components of the system. However, by activating the patient lift, effective accelerations in the incubator were decreased to less than 0.1 m/s2 across the whole frequency spectrum evaluated. The single measurement at a newborn's head revealed similar acceleration forces at the head of the baby and under its head. CONCLUSIONS: Utilization of a pneumatic patient lift can reduce acceleration forces. However, our results show that each system (car, incubator, and its base) has to be investigated and optimized for this purpose as a unit. Optimization of the complete system is necessary not only before its primary use but also in regular intervals over the years. Sometimes, further improvements can be reached with minor modifications such as the exchange of worn out rubber buffers.

Acceleration↗
PubMedDate not supplied

[Phenotypic differences between CD34 positive cells in various transplantation tissues].

Transplantations to restore the hematopoietic system were originally performed with cells from the bone marrow (BM) (20) which was considered the only cell source comprising repopulating progenitor cells. The discovery that chemotherapy induced the mobilization of CD34+ cells into the peripheral blood (PB) (14) gave rise to the successful autologous transplantation of PBSC (1, 13). Also cord blood (CB) was found to contain considerable numbers of "stem cells", and to date at least 42 allogeneic transplantations have been performed with this cell source (22, J. Wagner, personal communication). Further investigations led to the successful autologous transplantation of positively selected CD34+ cells from BM and PB (18), and the latest results indicate that it is promising to transplant purified CD34+ cells obtained from cytokine-stimulated donors (4, 10, 15-16). Despite such achievements it remains unclear how many "stem cells" are required per kg of the recipient and how they are phenotypically characterized. In this communication we give examples of typical differences observed by flow cytometry and clonogenic assay between the CD34+ cells contained in the different cell sources. They may explain why it is not sufficient only to analyze the CD34+ cell populations which may represent progenitors of different lineages as well as of various states of differentiation. CB CD34+ cells are early myeloid progenitor cells with the highest incidence of CFU-mix among the three cell sources. They have a high proliferative potential in vitro. They hardly coexpress B cell antigens and they are partially negative for CD38.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Influence of fractionated total body irradiation on mucosal toxicity in intensified conditioning regimens for autologous bone marrow transplantation in pediatric cancer patients.

From April 1988 to March 1991 28 children with generalized solid tumors (N = 15) or hematologic malignancies (N = 13) received intensified myelotoxic regimens followed by autologous stem cell rescue (ABMT). These intensified regimens consisted of 12 Gy fractionated total body irradiation (FTBI) and 2 (or 3) cytotoxic drugs (group A, n = 19) or a combination of 3 cytotoxic drugs (group B, n = 9). FTBI-containing regimens produced more severe mucositis > = WHO grade 3 (p = 0.01) and a longer duration of severe mucositis. The mucositis had a median duration of 8 days (range 0-28) in group A compared with median 0 days (range 0-7) in group B (p < 0.01). Acute renal and liver toxicity were not different. The probability of overall survival at day +100 was 89% in all patients. In terms of long-term survival FTBI containing regimen did not prove superior: 5 out of 19 patients in group A and 6 out of 9 patients in group B have been survivors for a minimum of 3 years. In conclusion, severe gastrointestinal toxicity of such intensive regimens is avoidable if FTBI is omitted.

Adolescent↗
PubMedDate not supplied

Enteroviral meningoencephalitis in immunocompromised children after matched unrelated donor-bone marrow transplantation.

Two children are described who presented with fever and generalized seizures, days 50 and 200, respectively, after matched unrelated donor-bone marrow transplantation. Upon antiepileptic treatment the seizures vanished but somnolence and fever remained. Magnetic resonance imaging (MRI) of the brain was performed and revealed transient asymmetric multifocal hyperintense lesions. Seizures were considered related to infection, and the cyclosporin A (CsA) treatment was not interrupted. Enterovirus was detected by reverse transcriptase-polymerase chain reaction in the spinal fluid of one patient and in the sputum of the other. Both children recovered completely within the next weeks without neurological sequel. This report shows that enteroviral meningoencephalitis can present with seizures during the post-transplant period. It highlights the importance of MRI for neuroimaging and of viral infections as differential diagnosis to CsA neurotoxicity.

Adolescent↗
PubMedDate not supplied

Genu valgum deformity in Hurler syndrome after hematopoietic stem cell transplantation: correction by surgical intervention.

Hematopoietic stem cell transplantation has increased the survival of patients with Hurler syndrome. Genu valgum occurs frequently in untransplanted patients and has been noted in 52% of our patients after stable engraftment. No deformities spontaneously corrected. We describe the orthopaedic management of genu valgum in Hurler syndrome. Medial epiphyseal stapling predictably affects angular deformity in these patients. Recurrence of deformities either after staple dislodgement or surgical removal can occur, and repeated stapling may be required. Surgical epiphyseal stapling has a role in the management of genu valgum in successfully engrafted Hurler patients. We discuss the relationship of this skeletal deformity to other skeletal deformities and alternative therapies for genu valgum.

Adolescent↗
PubMedDate not supplied

High-dose melphalan, etoposide +/- carboplatin (MEC) combined with 12-gray fractionated total-body irradiation in children with generalized solid tumors.

Long-term disease-free survival is poor in patients with primary generalized or relapsed solid tumors. High-dose chemoradiotherapy with stem cell rescue improved survival, but more effective protocols are needed. From January 1988 to November 1988, we treated 7 patients (median age, 9 years; range, 3-23 years) with an intensified treatment program. They received 12-Gy fractionated, total-body irradiation (FTBI). High-dose chemotherapy (MEC) consisted of melphalan (120-140 mg/m2 Mel) and etoposide (40-60 mg/kg VP-16) with or without carboplatin (1.5 g/m2 CBDCA). Although we combined 12-Gy FTBI with Mel, VP-16, +/- CBDCA in doses used previously for high-dose single-agent chemotherapy, the extramedullary toxicity of FTBI with ME(C) was tolerable. Two of the four patients who were grafted without delay after good initial chemotherapy response are still alive in continued complete remission 30 and 33 months, respectively, after initial diagnosis. Early application of FTBI and ME(C) during first chemotherapy response might improve outcome in patients with primarily generalized solid tumors.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Limited tolerance of intensified conditioning regimens in children receiving methotrexate/cyclosporin A for graft-versus-host disease prophylaxis.

Twenty-one patients with a median age of 9 years (0.5-19) underwent intensified myeloblative therapy: 1800 mg/m2 etoposide (VP) was added to 120 mg/kg cyclophosphamide (CY) and 12 Gy fractionated total body irradiation (FTBI) or 12-16 mg/kg busulfan (BU) for treatment of acute lymphoblastic leukemia (11 patients), acute myeloid leukemia (8 patients), non-Hodgkin's lymphoma (1 patient), or myelodysplastic syndrome (1 patient). Severe liver toxicity occurred in 5 of 7 children (71%) receiving short-term methotrexate (MTX) and additional cyclosporin A (CSA) for prophylaxis of graft-versus-host disease (GVHD). Three of them died of subsequent acute renal failure on days 8, 13, and 34. In contrast, acute severe organ toxicity occurred in only 1 of 14 children (7%) receiving the same intensified regimens who were autografted (7 pts) or received MTX alone for GVHD prophylaxis (7 pts). These observations suggest that GVHD prophylaxis with MTX and CSA may adversely influence the tolerance of intensified antileukemic regimens in children.

Adolescent↗
PubMedDate not supplied

Conventional vs. liposomal amphotericin B in immunosuppressed children.

Invasive fungal infections, mostly caused by Candida and Aspergillus species, are a major cause of early morbidity and mortality in immunocompromised children. The treatment of choice for systemic fungal infections is still the early intravenous administration of amphotericin B. However, conventional AMB therapy is often limited by severe side effects such as fever, chills, bronchospasm, and nephrotoxicity. In recent reports liposomal AMB (AmBisome) was shown to be effective in the treatment of severe systemic fungal infections. So far, clinical experience with AmBisome in children is still anecdotal and no comparative study is yet available. In the following we report on 11 immunosuppressed children who were treated with conventional or liposomal AMB for longer than 3 weeks.

Adolescent↗
PubMedDate not supplied

High-dose cyclophosphamide, adriamycin, and vincristine (HD-CAV) in children with recurrent solid tumor.

A dose-intensive regimen of cyclophosphamide (140 mg/kg over 2 days), doxorubicin (Adriamycin, 75 mg/m2 over 3 days), and vincristine (1 mg/m2 on days 1, 2, and 3 and 1.5 mg/m2 on day 9) was tested in 18 children and adolescents with poor-prognosis recurrent or refractory solid tumors. Nine were affected by neuroblastoma, 3 by Ewing's tumors, 2 by rhabdomyosarcoma, 2 by synovial sarcoma, 1 by hepatocellular carcinoma, and 1 by osteogenic sarcoma. All enrolled patients were heavily pretreated, including 2 patients after bone marrow transplantation. Forty courses were applied (median, 2). The overall response rate was 33% (2 complete remissions and 4 partial remissions). Responses were obtained in children with neuroblastoma, Ewing's tumors, and hepatocellular carcinoma. Myelosuppression [World Health Organization (WHO) grade IV after all courses] and cardiac toxicity (3 WHO grade I, 5 WHO grade III, and 3 WHO grade IV) were the main side effects. Nephrotoxicity and hepatoxicity were not observed. With further therapy consisting of surgery, radiotherapy, and high-dose chemotherapy [cisplatin, carboplatin/etoposide (VP16), or ifosfamide/VP16 with or without autologous stem cell reinfusion after conditioning with melphalan/VP16/carboplatin], 3 complete remissions and 5 very good partial remissions were obtained. Ten of 18 patients are alive after a median follow-up of 16 months.

Adolescent↗
PubMedDate not supplied

Formative and effectiveness evaluation of a worksite program promoting healthy alcohol consumption.

PURPOSE: This project involved the formative and effectiveness evaluation of a program aiming to enable working, nondependent drinkers to consume alcohol in a healthy and socially responsible fashion. DESIGN: A baseline survey (n=387) of employee needs and interests was followed by a formative evaluation testing accessibility, interest/resistance, and potential effectiveness. The formative evaluation used successive iterations of focus groups. The subsequent effectiveness evaluation (n=268) used a randomized pre-post design with three conditions: alcohol program, placebo (nutrition) program, or no program. SETTINGS AND SUBJECTS: The program was implemented in a multi-branch, blue-collar, shiftworking organization (n=813) in four Quebec cities with many mobile workers. INTERVENTION: The worksite alcohol program consisted of two, half-hour sessions delivered one week apart by a health professional during paid time. The program provided information on the social and personal costs of alcohol, on strategies for promoting socially responsible drinking, and for the prevention of negative consequences of intoxication for oneself and one's family and friends. MEASURES: Constructs measured using self-administered questionnaires were: alcohol knowledge, socially responsible attitudes, perceived self-efficacy for drinking management, and self-reported drinking behavior. RESULTS: Despite the lack of interest in the topic (as found in the needs and interests survey), the program was effective in promoting socially responsible attitudes and reducing self-reported weekly consumption among participants. Some placebo effects were also present. Participants were not completely representative of all employees. CONCLUSION: Worksite alcohol health promotion programs can be effective especially when promoting socially responsible attitudes.

Alcohol Drinking↗
PubMedDate not supplied

A qualitative investigation of organizational issues in an alcohol awareness program for blue-collar workers.

PURPOSE: To explore sociopolitical and organizational issues in worksite alcohol health promotion. Few such programs are reported in the literature. DESIGN: Qualitative data were gathered during the development and implementation phases of a program through focus groups, key informant interviews, and observations made by the research team. SETTINGS AND SUBJECTS: One hundred and ninety-nine blue-collar workers from a private company (a group which was also involved in a randomized controlled trial) and 123 workers from four other organizations (nontrial groups) received the intervention. The nontrial groups were used to pilot-test the intervention and in a post-trial assessment. All companies were located in Montreal, Quebec, Canada. INTERVENTION: Two worksite health promotion sessions on responsible drinking were given to small groups of workers. MEASURES: The reactions of workers, unions, and employers to the program and to the evaluation trial were observed. The viewpoints of key informants were solicited through semi-structured interviews. Analysis was accomplished through several cycles of memo writing. RESULTS: Alcohol is a sensitive subject when discussed in worksite group settings. Our data suggest that there are alcohol problems in the workplace of which coworkers are clearly cognizant. In one setting the intervention led to the development of organizational rules regarding workers who reported to work inebriated, where this behavior had been previously tolerated. The sessions were better received when disease concepts were avoided. Evaluation research on alcohol requires particular care with confidentiality and ongoing communication with all stakeholders, especially unions. CONCLUSIONS: Worksite health promotion regarding alcohol is feasible.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Drinking↗