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Biomedical subjects

A Attanasio

Publications and source records attributed to A Attanasio.

At least 55 records · Page 3Linked to original sources
PubMed1993

Dose-dependent effect of growth hormone therapy on glucose metabolism in subjects with Turner syndrome. The German Lilly Ullrich-Turner Syndrome Study Group.

Recombinant human growth hormone (GH) is effective in promoting growth velocity in subjects with Turner syndrome. As higher doses are used for this indication than for substitution therapy in GH deficiency, the long-term effects of GH therapy on carbohydrate metabolism represent a safety issue; this is particularly important in Turner syndrome, in which there is an increased prevalence of impaired glucose tolerance. So far, GH therapy has been given to patients with Turner syndrome for up to 7 years without any significant changes having been reported in glycosylated haemoglobin (HbA1c) values, unstimulated and stimulated oral glucose tolerance test (OGTT) blood glucose and serum insulin concentrations. These findings may, however, be influenced by other variables, such as study design, number of subjects or standardization methods applied. Results of an ongoing trial in the FRG, from which 2 years' data on glucose metabolism (as assessed by serial OGTTs) of 72 patients with Turner syndrome are available, indicate that glucose homoeostasis is maintained at the expense of an increase in insulin secretion, which is time- and dose-dependent. Although these changes may be fully reversible on withdrawal of GH. therapy, accurate control of glucose metabolism both during and after GH. treatment is advocated.

Blood Glucose↗
PubMed1993

Postembedding staining of brain tissue for ultrastructural visualization of amyloid in Alzheimer's disease.

A postembedding staining method is presented for ultrastructural visualization of amyloid deposits in brain sections from patients with Alzheimer's disease. Methenamine silver stain is applied to thin sections of tissue embedded in the acrylic resin LR Gold. Senile plaques are easily labeled by silver granules and the ultrastructural detail is well preserved. When staining time is prolonged, silver precipitate also is deposited on neuronal paired helical filaments. This method overcomes the drawbacks of previously reported applications of the stain on Vibratome and Epon sections. Thin sections from the same tissue block can be immunostained with antibodies to various plaque components, thus allowing comparative studies at the electron microscope level.

Acrylic Resins↗
PubMed1993

Peripherin immunoreactive structures in amyotrophic lateral sclerosis.

BACKGROUND: Increased levels of the neuron-specific intermediate filament, peripherin, have been recently detected in regenerating motor neurons of rat spinal cord after nerve transection. No data are yet available on peripherin expression in normal and diseased human spinal cord. EXPERIMENTAL DESIGN: We have investigated the presence of peripherin immunoreactive structures in routinely processed spinal cord of human patients with amyotrophic lateral sclerosis and control cases by immunohistochemistry and immunoelectron microscopy. Adjacent sections were stained with antibodies to neurofilaments (NF) and ubiquitin. RESULTS: In control cases, immunoreactivity for peripherin was found in neurons of dorsal root ganglia, in the posterior columns, in dorsal and ventral roots, and in scattered age-related axonal swellings. The cytoplasms of motor neurons were unstained. In amyotrophic lateral sclerosis cases most spheroids were immunoreactive for NF and to a lesser extent for peripherin. A few spheroids were strongly reactive for peripherin and were only weakly stained by antibodies to NF in adjacent sections. Both antibodies to NF and peripherin failed to demonstrate structures corresponding to the intraneuronal filamentous inclusions labeled by ubiquitin. CONCLUSIONS: The accumulation of peripherin and NF in spheroids is likely related to the reduced anterograde transport. Alternatively, the spheroids showing a higher degree of peripherin immunoreactivity might represent regenerating axonal terminals.

Aged↗
PubMed1992

LR Gold embedding of nervous tissue for immunoelectron microscopy studies.

A major drawback of all acrylic resins commonly used for post-embedding immunocytochemical studies of the central nervous system is the disruption of the ultrastructural morphology, due to the high lipid content of neural tissue. We have investigated the suitability of the acrylic resin LR Gold, which has been employed recently for immunogold labeling studies in several non-neural tissues. Optimal preservation of both antigenicity and ultrastructure of nervous tissue was obtained after en bloc staining with uranyl acetate, followed by total dehydration in acetone and curing at low temperature. Cell membranes and myelin sheaths, which are usually lost with other acrylic resins, were well maintained. The degree of antigenicity of LR Gold-embedded tissues was comparable to that of LR White-embedded one, but the morphologic detail was much better preserved. The use of LR Gold is particularly advantageous for studying neurodegenerative disorders such as Alzheimer disease.

Acrylic Resins↗
PubMed1992

Age-related ubiquitin deposits in dystrophic neurites: an immunoelectron microscopic study.

Widespread neuritic dystrophy is a hallmark of Alzheimer's disease (AD) and, in a less severe form, of brain ageing in various mammalian species. By immunohistochemistry, diffuse dot-like staining for ubiquitin (Ubq), a polypeptide involved in the degradation of abnormal and short-lived proteins, has been associated with human brain ageing. The nature of the Ubq deposits was investigated by immunogold electron microscopy on autopsy samples from aged human and dog brains. Most of the dot-like staining was localized to the white matter and corresponded to myelinated dystrophic neurites filled by Ubq-labelled lysosomal dense bodies. They did not contain paired helical filaments or multilamellar bodies. A minority of Ubq deposits was represented by amorphous densities in focal enlargements of the myelin sheaths. Our findings show that the spectrum of Ubq changes in ageing brain is wider than formerly recognized, and support the hypothesis that a defective regulation of the lysosomal system might be involved in the pathogenesis of structural abnormalities both in the ageing brain and in Alzheimer's disease.

Aged↗
PubMed1992

Prevalence of autoantibodies to endocrine organs in girls with Ullrich-Turner syndrome aged 5-14 years.

Endocrine function tests and a broad panel of autoantibodies to endocrine organs were assessed in 77 patients aged 5-14 years with Ullrich-Turner syndrome (UTS), who were included in the German UTS Multicenter Study. None of these patients had abnormal pituitary, thyroid or adrenocortical function, as assessed by the adequate hormone tests. Antibodies to thyroid microsomes were found in 3 of the 77 (3.9%), antibodies to thyroglobulin in 0/77, antibodies to adrenocortical cells in 1/77 (1.3%), gastric parietal cell antibodies in 2/77 (2.6%), and anterior pituitary cell antibodies in 3/77 (3.9%) probands. These prevalences were not significantly higher than those obtained in 154 age- and sex-matched normal control children when 2 control subjects were assigned to each patient with UTS. Our data do not show an increase in serological signs of endocrine autoimmunity in young patients with UTS suggesting that a putative association of these syndromes does not exist from birth and is not usually present in childhood. However, we cannot exclude the possibility that UTS is associated with factors that render these patients more susceptible to endocrine autoimmunity later in life.

Adolescent↗
PubMed1991

Dystrophic neurites around amyloid plaques of human patients with Gerstmann-Sträussler-Scheinker disease contain ubiquitinated inclusions.

Dystrophic neurites have been previously observed around prionic protein-derived amyloid plaques of Gerstmann-Sträussler-Scheinker (GSS) disease. Ubiquitin (Ubq) immunohistochemistry reveals the presence of dot-like stainings around many of these plaques. In order to determine the nature of ubiquitinated deposits, we performed an immunogold electron microscope study on autoptic samples from the cerebellum of a GSS patient. Both pre- and post-embedding staining methods showed Ubq-positive dense bodies and filamentous structures, belonging to dystrophic neurites. They are analogous to ubiquitinated neuritic processes described around cerebellar amyloid plaques of Alzheimer's disease (AD). These results suggest that amyloid deposition is responsible for the degeneration of adjacent axon terminals in both AD and GSS.

Amyloid↗
PubMed1991

Ultrastructural localization of factor VIII-related antigen in endothelial proliferations of malignant gliomas.

The ultrastructural localization of Factor VIII-related antigen (FVIII/RAg) in the endothelial cells of malignant gliomas was studied with immunogold labelling on thin sections of LR White-embedded tissue. FVIII/RAg was localized in Weibel-Palade bodies (WPBs) as well as in cytoplasmic vacuoles and vesicles, and in extracellular spaces. Stained WPBs were found both in cells surrounding vascular channels and in several proliferating cells of solid buds and glomeruli. Our results confirm previous ultrastructural observations on non-neural tissues that FVIII/RAg is produced by endothelial cells and stored in WPBs. The presence of FVIII/RAg-stained WPBs in capillary buds and tufts indicates that at least some of the proliferating cells are endothelial in origin rather than pericytes. Thus, the contribution of endothelial cells to new vessel formation seems to be more substantial than previously reported.

Antigens↗
PubMed1991

Continuous intravenous infusion of TRH-T: clinical, cardiovascular and endocrinological effects.

Seven patients, six suffering from amyotrophic lateral sclerosis (ALS) and one from Friedreich ataxia, were treated with a placebo i.v. infusion during the first day and with TRH-T i.v. infusion at a rate of 2 mg/h for 8 h daily (total daily dosage 16 mg) on the 2 consecutive days. Continuous blood pressure (BP) and EKG monitorings were performed during 3 days infusion. Blood samples were collected for endocrinological evaluations. The neurological evaluation after acute TRH-T treatment showed an objective improvement in 3 of the 8. We found significantly higher values of systolic (max. difference of 10.1 mm Hg) and diastolic (max. difference of 8.8 mm Hg) BP than during placebo, beginning from the 5th h of the infusion (p less than 0.05). A trend in progressive increase of the heart rate (HR) reached statistical significance (p less than 0.01) at the 8th h of the second TRH-T infusion. The cardiovascular changes during the i.v. continuous TRH-T infusions were clinically irrelevant and never required the interruption of the treatment.

Adult↗
PubMed1991

Two methods for flat embedding sections in LR white cut from paraffin blocks.

Two simple methods are described for flat embedding of sections cut from paraffin blocks of brain tissue in the hydrophilic resin LR White. The ability of fresh resin to polymerize when added to already cured resin is exploited. In the first method, a tissue section with a drop of LR White is pressed to the bottom of a gelatin capsule using a blank block. In the second method, the section in a drop of resin is sandwiched between the sawed halves of a blank block. After curing, thin sections containing large areas of tissue can be collected and processed for immunocytochemistry.

Acrylic Resins↗
PubMed1989

[Efficacy of flecainide in the treatment of ventricular tachycardia in the elderly. Dynamic electrocardiographic study].

The antiarrhythmic activity of flecainide has been tested in seven old patients (mean age 71 years) suffering from recurrent episodes of ventricular tachycardia. A basal 24-hour dynamic electrocardiogram was recorded for each patient and was repeated on day 5 of oral flecainide treatment (200 mg). A significant reduction (p less than 0.0001) of premature ventricular beats, of bigeminism (p = 0.0025) and of the episodes of ventricular tachycardia (p = 0.017) was obtained with plasma flecainide levels between 322 and 614 ng/ml. In addition, sinus rhythm was restored in two patients with stable atrial fibrillation and in the others ectopic atrial beats were markedly reduced. Among the ECG parameters examined, only QRS was significantly increased (p = 0.034). No significant change of blood pressure and laboratory parameters was observed. Untoward side effects were not observed.

Aged↗
PubMed1989

[Current knowledge and problems of accelerated idioventricular rhythm. Clinical observations and indications for therapy].

The authors report on present knowledge and questions concerning Accelerated Idioventricular Rhythm (AIR). The electrocardiographic characteristics and the supposed electrophysiologic mechanisms are analyzed and compared to ventricular tachycardia (VT). The authors emphasize that AIR is not a single entity: in some cases it may represent an unusual form of VT, in others a separate ventricular arrhythmia.

Electrocardiography↗
PubMed1989

Cardiovascular effects of lisuride continuous intravenous infusion in fluctuating Parkinson's disease.

The cardiovascular effects of a continuous intravenous infusion of lisuride plus oral domperidone were studied in 16 fluctuating parkinsonian patients as compared to their usual oral therapy with levodopa plus carbidopa. The study was performed using a 24-h ambulatory recording and an automatic noninvasive device for blood pressure monitoring. During lisuride infusion, a significant increase of systolic blood pressure was observed; however, in three patients, a decrease of systolic-diastolic blood pressure occurred; furthermore, a mild increase of atrial arrhythmias and, in two patients, a short run of atrial fibrillation were noted. Asymptomatic orthostatic hypotension, observed in seven patients during levodopa therapy, disappeared during lisuride infusion. Paradoxical hypertensive effects and disappearance of orthostatic hypotension observed in our patients seem related to the concurrent administration of domperidone.

Adult↗