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Biomedical subjects

C Berger

Publications and source records attributed to C Berger.

At least 163 records · Page 9Linked to original sources
PubMed1995

Kinetics of folding of leucine zipper domains.

Leucine zippers are short coiled coils frequently found in transcription factors where they serve as dimerization domains. The basic features contributing to the thermodynamic stability of leucine zippers are well understood, but very little is known about their folding kinetics. Leucine zippers have a simple and well defined structure and are, therefore, excellent models for the study of the concerted folding and assembly of polypeptide chains. Here we report on a fluorescence stopped flow investigation of the kinetics of association and dissociation of a series of model leucine zippers based on the common sequence Xzero-EYEALEKKLAAX1EAKX2QALEKKLEALEHG-amide (Xzero = N alpha-acetyl, N alpha-fluorescein-GGG, or N alpha-dimethylaminocoumarin-GGG; Xl = Leu or Ala; X2 = Leu, Ala, or Asn). When Xzero is fluorescein, self-quenching between adjacent fluorophores leads to a decrease in fluorescence emission intensity whereas unfolding of the coiled coil leads to an increase. In a heteromeric coiled coil containing both fluorophores, resonance energy transfer between the donor coumarin and the acceptor fluorescein is observed, and the mixing of labeled and nonlabeled peptides allows the measurement of the rates of strand exchange between leucine zippers. Exchange rates do not depend on peptide concentration, indicating that strand exchange is governed by the rate of dissociation of the coiled coil. Strand exchange between leucine zippers with X1 and X2 = Leu occurs with a half-time of approximately 30 min. A single Leu/Ala substitution at X1 or X2 decreases the half-time to approximately 1 s. Folding was also studied in a relaxation experiment in which a preexisting equilibrium between monomeric chains and coiled coils was rapidly disturbed by dilution with buffer, and the relaxation to the new equilibrium was followed by the increase in fluorescence. In peptides with X1, X2 = Ala or X1 = Ala, X2 = Asn the folding process can be described by a simple two-state monomer<-->dimer equilibrium with k(on) approximately 4 x 10(6) M-1 s-1 and k(off) approximately 10 s-1. Kd = k(off)/k(on) approximately 2.5 microM is in good agreement with the value of Kd obtained from equilibrium measurements. The peptides with a single Ala at X1 or X2 exhibit biphasic folding kinetics. One phase is concentration dependent and the other apparently concentration independent. This behavior can be interpreted as a monomer<-->dimer equilibrium coupled to an equilibrium between different conformational isomers. Leu to Ala and Leu to Asn substitutions in the hydrophobic core alter the folding kinetics in a position-dependent manner.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1995

Stereotactic radiosurgery: the Lyon experience.

From 10/1989 to 12/1992, 135 patients were treated, in Lyon, by Stereotactic Radiosurgery (RS) +/- External beam Radiotherapy (EBRT). Indications were AVMs or tumours that could not be cured by embolisation or/and surgery and are not larger than 30 to 35 mm. Lesions received 15 to 20 Gy (70% isodose) in one course. Among the 42 AVMs, only one rebled 6 months after RS and 9/15 had clinical improvement. Thirty-one had a radiological follow-up of 4 to 29 months after RS. Ten were totally obliterated, seven regressed more than 80% and six had a reduction of 50 to 80% of their AVM. Three grade 3 radio necrosis occurred for a cerebral trunk AVM and two large lesions. Three of the 15 treated meningiomas progressed after RS, 2 of them were controlled by conventional surgery. Four out of nine presenting symptoms had clinical improvement and, with a radiological follow-up of 4 to 24 months, 5 were stabilised and 6 regressed. Two grade three complications occurred for large lesions. The biological and radiological results of RS were good for the 42 treated pituitary adenomas but the high visual complication rate (12/42 with 8 grade 3) was too important and we stopped RS for these tumours except for small (less than 2 cm) adenoma at some distance from the optic chiasma. The visual complications were related to the tumour volume, the distance between the adenoma and the visual tract and pre-existent visual alterations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1995

Comparison of C-reactive protein and white blood cell count with differential in neonates at risk for septicaemia.

UNLABELLED: We prospectively compared the diagnostic value of C-reactive protein (CRP) and white blood cell counts for detection of neonatal septicaemia. Sensitivity and specifity in receiver operating characteristics, and positive and negative predictive value of CRP and white blood cell count were compared in 195 critically ill preterm and term newborns clinically suspected of infection. Blood cultures were positive in 33 cases. During the first 3 days after birth CRP elevation (sensitivity 75%, specifity 86%), leukopenia (67%/90%), neutropenia (78%/80%) and immature to total neutrophil count (I/T) ratio (78%/73%) were good diagnostic parameters, as opposed to band forms with absolute count (84%/66%) or percentage (79%/71%), thrombocytopenia (65%/57%) and toxic granulations (44%/94%). Beyond 3 days of age elevated CRP (88%/87%) was the best parameter. Increased total (84%/66%) or percentage band count (79%/71%) were also useful. Leukocytosis (74%/56%), increased neutrophils (67%/65%), I/T ratio (79%/47%), thrombocytopenia (65%/57%) and toxic granulations had a low specifity. The positive predictive value of CRP was 32% before and 37% after 3 days of age, that of leukopenia was 37% in the first 3 days. CONCLUSION: During the first 3 days of life CRP, leukopenia and neutropenia were comparably good tests while after 3 days of life CRP was the best single test in early detection of neonatal septicaemia. Serial CRP estimations confirm the diagnosis, monitor the course of infection and the efficacy of antibiotic treatment.

C-Reactive Protein↗
PubMed1995

Dialysis staff influence patients in formulating their advance directives.

Patients on chronic dialysis were surveyed to determine the degree to which completion of advance directives (ADs) was influenced by personal factors that patients bring to their dialysis situation (eg, demographic characteristics or personal preferences) and by environmental factors that are not under their control (eg, interaction with dialysis staff or hospital system). Of the 113 questionnaires distributed to the population of 40 hemodialysis and 73 peritoneal dialysis patients, 90 (80%) were completed. Although only 17% of the respondents had actually completed written ADs previously, respondents seemed to have a good general understanding of ADs, as evidenced by the 80% overall accuracy on a 19-question portion of the survey that tested knowledge regarding ADs. While a few personal factors, such as gender, dialysis, modality, perceived quality of life, and attitude toward death, were associated with completion of ADs, most other demographic variables, including age, marital status, religion, work status, number of years of education, disability status, locus of control, renal diagnosis, and number of years on dialysis, were not correlated. More prominently correlated with completion of ADs were environmental factors, such as having dialysis staff discuss ADs with patients, patients being asked to complete ADs at the time of hospitalization, and perception of staff as being comfortable discussing ADs with patients. The overall results of the survey suggest that discussing ADs as an ongoing activity may have been positively influenced by the Federal Patient Self-Determination Act of 1991.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Abdomino pelvic irradiation after second-look laparotomy for stage III ovarian carcinoma.

OBJECTIVE: The purpose of this retrospective analysis of 34 patients with stage III ovarian carcinoma was to review results and morbidity of whole abdominal irradiation after surgery and chemotherapy. METHODS AND MATERIALS: All of the 34 patients had reached a complete clinical remission after first cytoreductive surgery and chemotherapy. After second-look laparotomy each patient underwent whole abdominal irradiation. Except for two patients with chronic myelosuppression, the dose administered was of 22.5 Gy to the abdominal cavity with a boost of 22.5 Gy added to the pelvis. RESULTS: Three and 5-year overall survival rates were 62% and 43%, respectively. Three and 5-year disease-free survival rates were 53% and 38%. Twenty-three patients (68%) developed local relapse or local disease progression. Metastasis occurred in five cases and were always associated with an abdominal cavity recurrence. Residual disease after first cytoreductive surgery appeared as a prognostic factor in univariate analysis. Patients with unresected residuum had a 5-year survival probability of 35% versus 83% for patients without residual disease. We observed 12% grade-3 intestinal toxicities and one fatal case of radiation enteritis. CONCLUSION: Despite its curative potential, the long term benefit of whole abdominal irradiation in the multimodality treatment of advanced ovarian carcinoma must be evaluated in well designed controlled trials.

Antineoplastic Agents↗
PubMed1995

Dilated cardiomyopathy and neonatal lethality in mutant mice lacking manganese superoxide dismutase.

The Sod2 gene for Mn-superoxide dismutase (MnSOD), an intramitochondrial free radical scavenging enzyme that is the first line of defense against superoxide produced as a byproduct of oxidative phosphorylation, was inactivated by homologous recombination. Homozygous mutant mice die within the first 10 days of life with a dilated cardiomyopathy, accumulation of lipid in liver and skeletal muscle, and metabolic acidosis. Cytochemical analysis revealed a severe reduction in succinate dehydrogenase (complex II) and aconitase (a TCA cycle enzyme) activities in the heart and, to a lesser extent, in other organs. These findings indicate that MnSOD is required for normal biological function of tissues by maintaining the integrity of mitochondrial enzymes susceptible to direct inactivation by superoxide.

Acidosis↗
PubMed1995

Malignant and normal T cells show random use of T-cell receptor alpha chain variable regions in patients with cutaneous T-cell lymphoma.

Cutaneous T-cell lymphoma (CTCL) is a malignancy of mature T lymphocytes, most of which express alpha/beta type T-cell receptors (TCRs). The cause of CTCL is unknown, but hypotheses postulating chronic stimulation of TCRs by superantigen or by a leukemogenic virus have been proposed. Either mechanism might produce bias in the TCR variable (V) region types used by the malignant cells. To determine if TCR alpha use is restricted in CTCL, we used reverse transcription and the polymerase chain reaction to determine V alpha and V beta usage by malignant cells purified from the peripheral blood of leukemic patients with CTCL. Usage of alpha chain V region segments appeared totally random; malignant lymphocytes isolated from each of six patients used different V alpha regions. As has been previously reported, no bias was found in beta chain V region usage either. In addition to productive (in frame) TCR V region mRNAs in malignant cells from each patient, we detected non-productive (out of frame) beta chain transcripts in these cells in two of six patients, and non-productive alpha chain transcripts in five of six. Residual normal peripheral blood lymphocytes from these patients showed a random, polyclonal or oligoclonal pattern of V region usage. We conclude that there is no bias in V region usage in CTCL, making it unlikely that interactions between superantigen or virus and the TCR V regions play a role in the pathogenesis of CTCL.

Aged↗
PubMed1995

Experience with liposomal Amphotericin-B in 60 patients undergoing high-dose therapy and bone marrow or peripheral blood stem cell transplantation.

60 patients undergoing bone marrow or stem cell transplantation were treated with liposomal Amphotericin-B for documented or suspected mycosis. 34 patients had a prior course of conventional Amphotericin-B with the following adverse effects: increasing creatinine above 1.4 mg/dl (n = 17), increasing creatinine below 1.5 mg/dl (n = 9), no response (n = 6), and clinical side-effects (n = 4). Liposomal Amphotericin-B failed in 6/7 patients with culture-proven mycosis who died from infection with Aspergillus (n = 2) and Candida (n = 4), respectively. One patient with Candida lambica sepsis was cured. No patient with clinically or serologically suspected or diagnosed infection died from mycosis. Liposomal Amphotericin-B was well tolerated in 57 patients, even after side-effects of the conventional formulation. Adverse effects occurred in three cases, requiring the withdrawal of the drug in one patient. Due to toxic side-effects of the high-dose therapy and transplant-related complications, it was difficult to evaluate the influence of liposomal Amphotericin-B on laboratory parameters. Eight patients showed a decrease of creatinine levels, which had increased above normal values under preceding therapy with conventional Amphotericin-B. Liposomal Amphotericin-B is well tolerated in patients undergoing high-dose therapy and bone marrow transplantation. The efficacy of liposomal Amphotericin-B needs to be investigated in randomized studies in comparison with conventional Amphotericin-B.

Adolescent↗
PubMed1995

[Fetal cerebral accident due to massive fetomaternal hemorrhage. A case report].

Massive fetomaternal haemorrhage (FMH) occurs in 0.12 to 0.5% of pregnancies. It is most often spontaneous and involves uncomplicated near-term pregnancies. It causes fetal anaemia, with or without fetal distress and hydrops fetalis. To our knowledge only one paper has reported a neurological complication (hemiplegia). We describe one case of FMH (maximal Kleihauer test = 6.5%) at 28 weeks gestation, which was spontaneous, reversible, associated with sinusoidal fetal heart rare (FHR) and hydrops fetalis; and complicated by an intraventricular antenatal haemorrhage at 30 weeks gestation. Echographic abnormalities decreased. The infant was born at 40 weeks gestation. Clinical examination was normal during the first week of life. At the age of 4 1/2 months, examination showed axial hypotonia and moderated dilatation of intracerebral lateral ventricules without any other brain damage. At the age of 24 months, the child had retarded walking and hypotonia. The outcome was spontaneously favourable with disappearance in utero of the intraventricular haemorrhage (HIV), without hydrocephalia or ischaemic lesions. Three cases of similar FMH have been reported but none of them described cerebral complications. Intrauterine intravascular transfusion should be proposed early. No single pathophysiological mechanism of FMH has been universally accepted and there is no aetiological treatment. The risk of recurrence of FMH in later pregnancies requires careful follow-up.

Adult↗
PubMed1995

Inhibition of CFU-C growth by VP-16 containing plasma samples obtained from patients after conditioning therapy for bone marrow transplantation.

The introduction of VP-16 into high-dose therapy regimens used for conditioning before BMT or PBSCT has resulted in higher remission rates and prolonged disease-free survival, even in high risk patients. VP-16 levels have been measured in plasma at the time of transplantation. The question is, is there a biological activity that corresponds with the risk of delayed engraftment or graft failure? We investigated the inhibitory effects of plasma samples obtained from patients under high-dose VP-16 therapy on the growth of human bone marrow progenitor cells. Bone marrow cells from healthy donors were exposed to the plasma samples and seeded into methylcellulose-culture (CFU-C-assay). We found a dose dependent CFU-C inhibition related to VP-16 plasma levels at the time of transplantation (k = 0.769, P < 0.01). There were signs of a correlation between CFU-C growth inhibition at the time of BMT and haematological recovery (k = 0.656, P < 0.05) between CFU-C inhibition and the time until leucocytes reached 0.2 x 10(9)/l. Patients with CFU-C growth inhibition at the time of BMT may show delayed engraftment of leucocytes and that there might be a correlation with VP-16 levels, but further investigation is necessary to determine the significance of the latter thesis and if VP-16 plasma levels could lead to failure of engraftment. We recommend a minimum time interval between VP-16 infusion and graft transplantation of 72 h.

Adolescent↗
PubMed1995

Bone marrow transplantation for Philadelphia-chromosome-positive acute lymphoblastic leukemia.

The outcome of 14 bone marrow transplants (BMT) (autologous 4; allogeneic 10) for Philadelphia-chromosome (Ph1) positive acute lymphoblastic leukemia (ALL) was analyzed. Preparative regimens consisted of etoposide (VP16) (30 or 45 mg/kg BW) (n = 14), cyclophosphamide (CY)(120 mg/kg BW) (n = 14), and total body irradiation (TBI)(12 Gy) (n = 13) or busulfan (Bu)(16 mg/kg) (n = 1). All patients receiving autologous marrow were in complete remission (CR) (three patients in 1.CR, one patient in 2.CR) at the time of BMT. For allogeneic BMT (nine related, one unrelated donor), seven patients were in first CR, two patients in first refractory relapse, and one patient in second relapse. With a median follow-up of 503 days (range 93-1522 days), eight out of 14 patients are alive in remission (six out of 10 patients receiving allogeneic, and two out of four patients receiving autologous BMT). Disease-free survival for all patients is 46%. Causes of death were relapse (n = 3) and transplant-related toxicity (n = 3). All patients tested for the bcr/abl rearrangement by reverse transcriptase-polymerase chain reaction (RT-PCR) were negative 4 weeks post-BMT. Two of the three patients who subsequently relapsed were repeatedly RT-PCR positive prior to relapse (test not done in the third). Considering the negligible cure rate of Ph1-positive ALL with conventional chemotherapy regimens, our data support the concept of early (> or = 1 CR) BMT (allogeneic > autologous (purged) following triple therapy with TBI, VP16, and CY.

Adult↗
PubMed1995

[Evaluation and analysis of social relationships of children in clinical practice and research: "Social Relationship Scale for Children"].

The Social Relationship Procedure for Children (Soziales Beziehungsverfahren f¿ur Kinder, SOBEKI), a technique employing figure tasks and interviewing, is a new clinical psychology assessment instrument for use with children. With this instrument it is possible to (a) determine the significant others (social network) of 6- to 12-year-old children, (b) measure how specific functions are divided among members of a child's social networks, and (c) visualizing cohesion and hierarchical structures of the children's networks within and outside their families. In the present paper the theoretical foundations, administration and assessment of the procedure are outlined. In addition, the results of a comparison of children with psychiatric disorders and a healthy control group are presented.

Child↗
PubMed1995

[Concomitant radiochemotherapy with cisplatin (CDDP), 5-fluorouracil (5-FU) and mitomycin C (MMC) in locally advanced carcinoma of the oropharynx. Results of a phase II trial].

In order to improve loco-regional control in locally advanced oropharyngeal carcinoma, a phase II trial was designed to establish the feasibility of concomitant conventional radiotherapy and three cycles of chemotherapy at day 1, 21 and 42 with cisplatin (CDDP) 20 mg/m2 and 5-fluorouracil (5-FU) 400 mg/m2 day 1 to day 4, and mitomycin C (MMC) 10 mg/m2 day 1. From March 1990 to September 1993, 27 patients (mean age: 55) were included in this study. Three patients (11%) were T2N0, 19 (70%) T3 (T3N0: n = 9, T3N1: n = 1, T3N2: n = 5, T3N3: n = 4), and 5 (19%) T4 (T4N0: n = 1, T4N1: n = 1, T4N2: n = 2, T4N3: n = 1). With a mean follow-up of 34 months (17-59), ten patients (37%) were alive, free of disease; among the 17 other patients, seven died with cancer. Loco-regional control rate was 85%. One and 2-year survival rates were respectively 48 and 31% for overall and disease-free survival; respective corrected overall survival rates were 68 and 61%. Grade 3 or 4 mucositis was 81%; enteral feeding was necessary for 63% of the patients; mean loss of weight was 5.7 kg. Grade > 2 thrombopenia occurred in 11 patients (41%), grade > 2 neutropenia in eight patients (29%) , grade > 2 anemia in four patients (15%). Febrile neutropenia or aplasia occurred in five patients (19%). Two patients (7%) died during treatment of haematological or infectious complications related to the treatment. Another patient died 2 months after treatment with grade 4 thrombopenia and septicemia. Addition of MMC to 5-FU and CDDP might have been partly responsible of this increased toxicity. A high complete response rate has been achieved with this concomitant radio-polychemotherapy, but with a severe digestive and haematological toxicity, which did not allow to conclude to the feasibility of this therapeutic association.

Adult↗
PubMed1995

[Post-partum dysthyroidism. Prospective study in a French region (1986-1988)].

UNLABELLED: Post-partum thyroiditis' prevalence has not been previously evaluated in France. OBJECTIVE: To study prospectively a cohort of delivered women to evaluate the prevalence of antimicrosomal antibodies and dysthyroidism during the post partum period. DESIGN, PATIENTS AND MEASURES: 400 women were observed 4 to 12 weeks after delivery and evaluated for the presence of a goiter and a measure of antimicrosomal antibodies (AMA) and us TSH. A subgroup of these selected women was then prospectively followed. HLA typing was also performed. RESULTS: 4 to 12 weeks after delivery, a goiter was found in 40 women. 19 women had positive AMA levels. No abnormality in thyroid function was detected during this period. In these selected women, 8 cases of dysthyroidism, mainly hypothyroidism, were diagnosed later on, 3 to 9 months after delivery. One of them became AMA positive during the follow-up, so the AMA prevalence was 5%. HLA DR4 and the hyplo-type HLA A3B7 were more frequent in this selected population. CONCLUSIONS: Post-partum thyroiditis is a rare and benign disease in France. The transient dysthyroidism occurs later than 3 months after delivery, mainly in women with positive AMA (5% of the parturients). HLA DR4 is more often encountered in this thyroid pathology, as already observed in other Caucasian populations.

Antibodies↗
PubMed1994

Abrogation of baboon natural xenoantibody to pig splenocytes by DL-penicillamine.

Natural xenoantibodies are believed to be IgM in nature and are known to play a critical role in the hyperacute rejection of distantly related xenografts. The purpose of this study was to determine whether the reducing agent DL-penicillamine could inactivate baboon natural xenoantibodies to pig splenocytes. Pooled baboon serum was treated with varying concentrations of DL-penicillamine over different lengths of time and a complement-mediated cytotoxicity assay was used to determine the reactivity of baboon natural xenoantibodies to pig splenocytes. A whole-cell ELISA assay was used to assess the binding of both IgG and IgM xenoantibodies to pig splenocytes. In addition, DL-penicillamine-treated serum was dialyzed to assess its potential clinical application. These in vitro experiments indicate that both IgM and IgG baboon natural xenoantibodies bind to pig splenocytes, but only IgM xenoantibody is cytotoxic. The binding of baboon natural IgM xenoantibody can be eliminated, and the cytotoxicity of IgM xenoantibody markedly reduced by DL-penicillamine treatment despite continued binding of IgG xenoantibody to pig splenocytes. In addition, DL-penicillamine can be dialyzed, suggesting that it may be an efficacious clinical treatment, the toxicity of which can be regulated with hemodialysis.

Animals↗
PubMed1994

Conservative treatment feasibility with induction chemotherapy, surgery, and radiotherapy for patients with breast carcinoma larger than 3 cm.

BACKGROUND: The traditional surgical treatment for operable breast carcinoma larger than 3 cm is mastectomy. To avoid mutilating surgery, the authors administered primary chemotherapy to 158 patients with operable nonmetastatic large breast carcinoma with a TNM classification of T2 greater than 3 cm and T3 with a lymph node status of N0-N1. Conservative treatment was proposed for patients responding to the chemotherapy and whose tumor was reduced to 3 cm or less. The purpose of the study was to evaluate the feasibility and treatment results of this strategy. METHODS: The mean patient age was 50.4 years. Eighty-two patients had T2 carcinomas greater than 3 cm, and 76 had T3 carcinoma. Fifty-four tumors were classified as lymph node status N0, and 104 as N1. Mean tumor size was 5.6 cm. Patients were treated with three courses of the NVCF regimen (mitoxantrone, vindesin, cyclophosphamide, and 5-fluorouracil) or the EVCF regimen, in which mitoxantrone was replaced by epirubicin every 4 weeks, and then administered with a radiosurgical combination. RESULTS: The overall response rate to induction chemotherapy was 60.8% with 20.2% complete tumor regression. Twenty-one percent of the patients experienced grade 3 or 4 chemotherapy toxic effects, which were all acceptable and reversible. Breast-conserving treatment was feasible in 48.7% of patients (77 of 158). Forty-five patients (28.5%) were treated with a radiosurgical combination (tumorectomy plus radiation therapy), whereas 32 (20.2%) were treated with radiotherapy alone (external irradiation and brachytherapy). Other patients were treated with mastectomy. Age, tumor stage, histology, hormonal status, and hormonal receptor rate had no influence on the frequency of the observed regressions. Isolated recurrences occurred in 11 patients, 6 who were treated conservatively and 5 who were treated with mastectomy. Metastatic relapses were observed in 38 patients (14.6% in the chemotherapy responders and 38.7% in the nonresponders) (P < 0.02). Five-year actuarial survival was 73.2% and was significantly higher for responders to the induction treatment. CONCLUSION: These preliminary results suggest that primary chemotherapy and radiosurgical breast-conserving treatment is feasible and is an alternative to mastectomy for patients with large operable breast carcinoma who are responders to the induction treatment. The long term benefit of this strategy must be evaluated in well designed controlled trials.

Antineoplastic Combined Chemotherapy Protocols↗