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Biomedical subjects

A Vlad

Publications and source records attributed to A Vlad.

At least 19 recordsLinked to original sources
PubMed2005

Thermopower of interacting GaAs bilayer hole systems in the reentrant insulating phase near nu=1.

We report thermopower measurements of interacting GaAs bilayer hole systems. When the carrier densities in the two layers are equal, these systems exhibit a reentrant insulating phase near the quantum Hall state at total filling factor nu=1. Our data show that, as the temperature is decreased, the thermopower diverges in the insulating phase. This behavior indicates the opening of an energy gap at low temperature, consistent with the formation of a pinned Wigner solid. We extract an energy gap and a Wigner solid melting phase diagram.

Journal Article↗
PubMed2004

GADA and islet cell antibodies in Romanian children and adolescents with diabetes mellitus.

UNLABELLED: Childhood type 1 diabetes is defined by autoimmunity and insulinopenia. Etiopathogenic definition based on biochemical characteristics has recently replaced the clinical definition based on insulin requirement for treatment. The aim of this study was to describe biochemical and clinical characteristics of children with clinically diagnosed type 1 diabetes, hospitalized at the "Cristian Serban" Center in Buziaş. PATIENTS AND METHODS: Fasting C peptide, HbA1c, islet cell autoantibodies (ICA) and antibodies against glutamic acid decarboxylase (GADA) were measured in 278 subjects aged (mean +/- SD; range) 15.1 +/- 4.8 (4-28) years, with a disease duration of 2.1 +/- 0.7 (1.1-3.1) years. GADA and ICA positivity was defined by values higher than the 95th percentile in 99 age-matched non-diabetic controls (0.4 units for ICA and 1.4 for GADA). RESULTS: As many as 66.2% of all patients had positive GADA and 10.1% had positive ICA. While 68.7% had at least one positive antibody, only 7.6% had both antibodies positive. As expected, most of the children (79.9%) had fasting C peptide values in the low range (<0.5 ng/ml), but 3 patients (1.1%) had biochemical signs of insulin resistance (C peptide concentrations >3 ng/ml). Two of the three insulin resistant children had positive GADA and one of them had positive ICA, therefore showing "mixed" features of both type 1 (autoimmunity) and type 2 diabetes (insulin resistance). CONCLUSIONS: Childhood diabetes is now acknowledged to be a complex disorder with heterogeneity in its pathogenesis, clinical course and outcomes. While type 1 diabetes is the most frequent form of diabetes among Caucasian children, measurement of diabetes autoantibodies and C peptide is necessary to better define the types of diabetes in youth.

Adolescent↗
PubMed2004

The value of basal C peptide and its relationship with pancreatic autoantibodies in young adults with type 2 diabetes mellitus.

UNLABELLED: It is well known that sometimes it is difficult to distinguish between type 1 and 2 diabetes mellitus using clinical criteria, in subjects with disease onset relatively early in adult life. The measurement of C peptide level and of immunological markers may represent important additional tools for establishing the correct diagnosis. The aim of the study is to assess the trend of basal C peptide in patients with clinical diagnosis of type 2 diabetes and to relate it to the type of treatment, the body weight and the positivity for pancreatic autoantibodies. PATIENTS AND METHOD: we studied a group of 268 patients with type 2 diabetes, aged between 30 and 50 years, with a diabetes duration of less than 5 years. In all patients, we measured basal C peptide, islet cell autoantibodies and antibodies against glutamic acid decarboxylase, computed the body mass index and recorded the current antidiabetic treatment. RESULTS: Based on basal C peptide value, diabetic subjects fell under 3 categories: a) low C peptide (<0.58 ng/ml): 7.5%, b) normal C peptide (0.58-2.70 ng/ml): 57.8%, and c) high C peptide (>2.70 ng/ml): 34.7%. Patients with low C peptide were treated more often with insulin, while those in high C peptide group received more often biguanides. A direct correlation between C peptide and body weight was established. Mean C peptide was lower in patients positive for at least one pancreatic autoantibody, compared to those who were negative for antibodies CONCLUSION: Low basal C peptide can be considered criterion for transferring the patients, initially diagnosed as type 2 diabetes, in the type 1 diabetes group.

Adult↗
PubMed1999

Immunization of chimpanzees with tumor antigen MUC1 mucin tandem repeat peptide elicits both helper and cytotoxic T-cell responses.

CTLs and antibody responses to the tumor-associated antigen MUC1 mucin can be detected in patients with adenocarcinomas of the breast, pancreas, colon, and ovary. However, neither response is generally effective at controlling disease. Methods to augment immunity to MUC1 are being designed, with the expectation that this will lead to an antitumor response. The key to eliciting potent immunity to tumor MUC1 may be in generating MUC1-specific T-helper cell responses, which, to date, have not been reported in cancer patients. We have recently demonstrated that a synthetic vaccine representing five copies of the MUC1 tandem repeat peptide can be used to prime MUC1-specific human CD4+ T cells in vitro. Here, we extend these studies to test the immunogenicity and safety of the tandem repeat peptide in the chimpanzee, which has the identical MUC1 tandem repeat sequence to the human. To promote induction of Th1-type responses, we used the novel adjuvant LeIF, a Leishmania-derived protein that is known to stimulate human peripheral blood mononuclear cells (PBMCs) and antigen-presenting cells, to produce a Th1-type cytokine profile. We found that MUC1 tandem repeat peptide administered with LeIF elicited positive, albeit transient, proliferative T-cell responses to MUC1 in the PBMCs from four of four chimpanzees. Immunization induced MUC1-specific IFN-gamma but not interleukin 4 expression in CD4+ T cells from PBMCs and draining lymph nodes. MUC1-specific CTLs were also generated that did not induce detectable autoimmune dysfunction during the 1 year of observation. We conclude that the MUC1 tandem repeat peptide can be used to elicit both T-helper and cytotoxic cell responses to MUC1 in the primate and holds promise as a safe and effective cancer vaccine.

Animals↗
PubMedDate not supplied

MTD calculations on quantitative structure-activity relationships of steroids binding to the progesterone receptor.

The minimal topological difference (MTD) method is used to describe quantitative structure-activity relationships (QSAR) for the progesterone-receptor binding affinity including 59 progestational steroids. Multiple correlation coefficients of r = 0.962 and r = 0.955 are obtained by use of the MTD variable and a measure of hydrophobicity for the series of progesterone and ethisterone derivatives, respectively. Hydrophobic effects are found to strongly influence receptor binding. In accordance with the hydrogen bonding concept, the optimized MTD receptor maps indicate cavity vertices in the regions of oxygen functions at C3 and in the 17 beta position. Receptor wall vertices are attributed in the areas of 4, 10 beta, and 13 beta substituents of 4-en-3-one steroids while 17 alpha side chains additionally contain receptor cavity vertices. A comparison of corresponding receptor maps suggests in accord with X-ray crystal structure data that progesterone and ethisterone derivatives are bound in somewhat different orientations relative to the receptor surface.

Animals↗
PubMedDate not supplied

Etiological, clinical and pathomorphological aspects of acute respiratory distress syndrome in children.

Acute respiratory distress syndrome (ARDS) is the result of severe injuries of different etiologies of the capillary system in patients with previously healthy lungs, resulting in noncardiogenic pulmonary edema. The authors studied 42 infants in whom the histopathologic aspects were suggestive for ARDS. The etiologic factors of this syndrome were: severe gastroenteritis with hypovolemic or endotoxic shock (13 cases), sepsis (9 cases), fulminans purpura (2 cases), severe neurological disorders (13 cases), pulmonary infections (5 cases). In such conditions, if the infant presents hyperpnea followed by generalised cyanosis, refractory to oxygen therapy, and if there are clinical and radiologic signs of acute pulmonary edema, the diagnosis of ARDS must be considered and a complete intensive care therapy is compulsory in order to alleviate the severe prognosis of this syndrome.

Acute Disease↗
PubMedDate not supplied

[Intestinal occlusion by persistence of the omphalo-enteric conduct in a 10-year old child].

The persistence of the omphalo-enteric conduct is a rare, but possible, cause of pathology in children. Haemorrhage and intestinal occlusion are the most frequent clinical presentations, usually in infants. We describe the case of a 10 year old boy, who was admitted in our department for what seemed first to be an acute appendicitis. During hospitalization, the clinical picture turned on to an intestinal occlusion, and the patient finally required surgery. We performed exploratory laparotomy and we discovered a mechanical occlusion by persistence of the omphalo-enteric conduct, which was treated according to standard protocols. The post-operative course was good, and the child was discharged 8 days after surgery. This case emphasizes that the persistence of the omphalo-enteric conduct should be sought as the source of symptoms in any child presenting with intestinal occlusion.

Child↗
PubMedDate not supplied

[Osteoarticular changes in childhood leukemia, lymphoma and neuroblastoma].

Osteoarticular changes may occur in up to 23% of the cases with Acute Lymphoblastic Leukemia (ALL) and even more frequent with Acute Myeloblastic Leukemia (AML). Most of the bone and joint pains are due to neoplastic infiltration, radiologically obvious as metaphyseal clear stripes, parietal enlargement, periosteal reaction, osteolysis and diffuse osteoporosis in the long bone. In Malignant Lymphomas (ML) the bone involvement is rarer, usually bone metastases identifiable with Tc scintigraphy being the cause. In Neuroblastoma (Nbl) cases, bone metastases are commonly associated with abdominal tumor beyond one year of age. Of the total ALL, AML, ML and Nbl cases treated in our Oncology Dept, we selected 43 children with osteoarticular involvement. The sex ratio was 24 boys to 19 girls and the specific malignancy was ALL in 25 cases, AML in 5 cases, ML in 2 cases and Nbl in 10 cases. The following biological parameters were monitored: type of onset, the localization and nature of the bone affectation, differential diagnosis, and the response to therapy. The presence of the osteoarticular involvement has proved to be of no prognostic significance. The spectrum of clinical manifestations varied from mild pain to severe disability, in 7% of the cases being the unique symptoms. The type of lesion did not rise important differential diagnosis issues, excepting the cases with unique osteolytic lesion or diffuse osteoporosis, where the rest of the data and the elevated urine vanilmandelic acid helped to establishing the diagnosis. We conclude that the osteoarticular involvement encountered in different malignancies in children is a major sources of diagnostic problems, but it is not associated with a significant outcome.

Bone Neoplasms↗
PubMedDate not supplied

[Achalasia in children: Diagnostic opportunities and therapeutical options].

Achalasia is a functional disorder of the distal esophagus, which fails to relax during swallowing. Although being rare, this disorder is the source of a significant morbidity, including developmental disorders in children. Several therapeutical options are available: myorelaxants administration, esophageal dilations and surgery--distal esophageal myomectomy followed by an antireflux procedure. The paper introduces our experience in treating a number of 5 children between 1991 and 1998.

Adolescent↗
PubMedDate not supplied

[Primary obstructive megaureter- diagnosis and treatment].

The authors have treated 13 cases of primary obstructive megaureter (POM) in children, presenting without vesicoureteric reflux. The diagnostic possibilities and the surgical approach options are discussed. Both Cohen and Leadbetter--Politano uretero-vesical reimplantation techniques proved to be successful in this series. Ureteric folding was done in 2 cases. Reported final results are good in 10 cases.

Adolescent↗
PubMedDate not supplied

[Chronic dacryocystitis fistulization in a Rubinstein-Taybi syndrome].

The article presents the treatment difficulties of the chronic dacryocystitis at an eight month old patient, diagnosed with Rubinstein-Taybi syndrome. The difficulties occurred as a result of numerous antibiotic treatments and surgical procedures suffered by the patient since his second week of life.

Dacryocystitis↗
PubMedDate not supplied

[Association of active pulmonary tuberculosis and pulmonary neoplasms].

Six cases are presented (out of a total of 11) with sputum positive pulmonary tuberculosis associated with bronchopulmonary carcinoma. The carcinoma developed during the evolution of 9 cases of active tuberculosis that had received a long discontinous treatment with tuberculostatic drugs. Only two of the 11 patients could be operated because the other 9 were hospitalized in the terminal stage of the disease, with invasive tumors. These had neither been suspected nor investigated for neoplasia. The use of all available means of investigation in the early stages of cancer can be of considerable help in the early detection of this disease and may allow for the application of surgical methods. Exploratory thoracotomy, together with extemporaneous histological investigation, are much more useful for the diagnosis than the expectative attitudes, which lead to theloss of the patient. Positive sputum should not eliminate the possibility of the association of tuberculosis with cancer.

Aged↗
PubMedDate not supplied

[Frequency of isolation of tuberculous bacilli as a function of some mechanical factors in patients with pulmonary tuberculosis].

A series of mechanical factors, such as postural changes and every day movements, favour mobilization of bronchoalveolar secretions and, hence, offer greater chanses of detecting the tuberculosis bacillus. It is recommended to collect, in out-patient units, two sputum samples, one in the morning and the second several hours later, after beginning the day's work.

Humans↗