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Biomedical subjects

A Brunetti

Publications and source records attributed to A Brunetti.

At least 19 recordsLinked to original sources
PubMed1996

Human diabetes associated with defects in nuclear regulatory proteins for the insulin receptor gene.

The control of gene transcription is mediated by sequence-specific DNA-binding proteins (trans-acting factors) that bind to upstream regulatory elements (cis elements). We have previously identified two DNA-binding proteins that specifically interact with two unique AT-rich sequences of the 5' regulatory region of the insulin receptor gene which have in vivo promoter activity. Herein we have investigated the expression of these DNA-binding proteins in cells from two unrelated patients with insulin resistance and non-insulin-dependent diabetes mellitus. In these patients, the insulin receptor gene was normal. In EBV-transformed lymphoblasts from both patients, insulin receptor mRNA levels and insulin receptor expression were decreased. The expression of nuclear-binding proteins for the 5' regulatory region of the insulin receptor gene was markedly reduced, and this defect paralleled the decrease in insulin receptor protein expression. These studies indicate that DNA-binding proteins to the regulatory region of the insulin receptor gene are important for expression of the insulin receptor. Further, they suggest that in affected individuals, defects in the expression of these proteins may cause decreased insulin receptor expression and insulin resistance.

Cell Extracts↗
PubMed1996

Morphologic alterations in the cilia of a cat.

Based upon ultrastructural findings and computed tomography, a presumptive diagnosis of feline primary ciliary dyskinesia was made in a 2.5-year-old cat. The cat demonstrated morphologic alterations in the ultrastructure of oviductal cilia. In the oviduct, axonemal abnormalities were detected in 132 (20%) of 660 cross-sectioned cilia. The main ultrastructural ciliary defects were a lack of central microtubules, transposition of peripheral doublets to the center of the axoneme, supernumerary microtubules, and morphologic abnormalities of peripheral doublets. Computed tomography of the chest was consistent with early lesions of bronchiectasis, suggesting chronic stagnation of respiratory secretions, attributed to abnormal function of respiratory cilia. Specifically, the cranial branches of the cat's bronchi were wider and thicker than those of five healthy controls. Foci of pleural thickening and interstitial enlargement were also observed.

Animals↗
PubMed1995

1H MR spectroscopy in patients with metastatic brain tumors: a multicenter study.

In a cooperative study involving six clinical MR centers, localized 1H MR spectroscopy was used to characterize untreated metastatic brain tumors (40 cases, 45 lesions). Cubic volumes (3.4 or 8 cm3) filled for more than 50% by metastatic brain tissue were examined by single-voxel double spin echo MRS, by using chemical shift selective imaging (CHESS) pulses for water suppression and TE = 135 ms. Choline (Cho), creatine (Cr) and N-acetyl aspartate (NAA) levels in brain metastases of mammary carcinoma (n = 13), lung cancer (n = 11) and melanoma (n = 10) were similar. Metastasis NAA/Cho signal intensity ratio varied between 0.00 and 1.17, compared with 2.68 +/- 0.56 (SD) in lobus occipitalis and 1.94 +/- 0.63 in corpus nuclei caudati region (P < 0.0001, both). 1H MR spectroscopy, although not suited to recognize the primary tumor of metastases, could serve as a clinical test for excluding (metastatic) tumor as cause of solitary focal brain disorders that are hard to diagnose with current imaging methods.

Adult↗
PubMed1995

Dermoid sinus and spinal malformations in a Yorkshire terrier: diagnosis and follow-up.

An unusual case of a Yorkshire terrier with a dermoid sinus associated with multiple spinal/costal malformations is described. The dog presented with ataxia and pain in the dorsal thoracic region. Diagnostic characterisation of the lesions was obtained with radiography, myelography and computed tomography. After surgical removal of the sinus, the dog showed marked clinical improvement over a two-year period.

Abnormalities, Multiple↗
PubMed1995

Effect of adenosine on cerebral blood flow as evaluated by single-photon emission computed tomography in normal subjects and in patients with occlusive carotid disease. A comparison with acetazolamide.

BACKGROUND AND PURPOSE: Acetazolamide is commonly used with single-photon CT to assess the cerebrovascular reserve in patients with internal carotid artery stenosis or occlusion. In this study we wanted to evaluate the effects of adenosine, a well-known vasodilatatory compound with a short biological half-life, on brain circulation in humans and compare the results with those of acetazolamide. METHODS: Acetazolamide (1 g) and adenosine (140 micrograms/kg per minute) were injected intravenously on different days in 6 normal subjects and 6 patients: 4 with unilateral stenosis, 1 with bilateral stenosis, and 1 with complete occlusion of the internal carotid artery. Changes in regional cerebral blood flow relative to that of the cerebellum (cortico/cerebellar ratios) from resting conditions were evaluated by 99mTc-hexamethylpropyleneamine oxime and single-photon emission CT. RESULTS: The measured blood flow ratios increased significantly in the normal group 20 minutes after acetazolamide injection in several cortical and subcortical regions, as well as at the 4th minute of a 6-minute adenosine infusion. Regional cerebral blood flow ratio values were higher after adenosine than after acetazolamide in both cortical (frontal and parietal) and subcortical (thalamus and basal ganglia) regions. In 4 of the 6 patients the side-to-side asymmetry increased from the basal resting condition after the injection of acetazolamide and even more so after the injection of adenosine. CONCLUSIONS: Adenosine infusion causes vasodilation of cerebral arteries and can be used for the investigation of cerebrovascular perfusion capacity in patients with carotid occlusive disease. One advantage in the use of adenosine over acetazolamide is the possibility of interrupting the test with reversal of clinical symptoms or patient discomfort within a few minutes.

Acetazolamide↗
PubMed1995

Decreased cerebral glucose metabolism in patients with brain tumors: an effect of corticosteroids.

The authors measured cerebral glucose metabolism (CMRglu) using [18F]fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) in patients with brain tumors to evaluate the effect of exogenous corticosteroids (in this instance, dexamethasone) on glucose metabolism. Fifty-six FDG-PET studies obtained in 45 patients with unilateral supratentorial brain tumors were analyzed. Patients with brain tumors were divided into three groups: 1) patients with cushingoid symptoms, who had been treated with combinations of radiotherapy and chemotherapy taking oral dexamethasone; 2) patients not taking dexamethasone but treated with radiotherapy; and 3) patients not taking dexamethasone who had not been treated with radiotherapy. Serial FDG-PET scans were obtained in eight of the cushingoid patients. Glucose metabolism was measured in the contralateral cerebral and ipsilateral cerebellar hemispheres in patients and compared to measurements taken from 19 normal volunteers. The authors found that in the cushingoid brain tumor patients there was a marked reduction in CMRglu compared to normal volunteers and other brain tumor patients (Kruskal-Wallis test; p 0.001). In the majority of patients who had serial FDG-PET scans, there was a decline in glucose metabolism over time and in one patient, in whom dexamethasone was reduced in dosage, there was a subsequent increase in CMRglu. The authors conclude that there is a generalized reduction in CMRglu in brain tumor patients taking dexamethasone compared to other brain tumor patients and normal volunteers, and that this effect is independent of radiotherapy, concurrent anticonvulsant medication, and transhemispheric functional disconnection (transhemispheric diaschisis).

Adult↗
PubMed1995

Correlative morphologic and functional imaging for diagnosis, staging and follow up in AIDS: an overview.

The immunocompromised patient can be affected by different opportunistic infections and tumors, that can involve all organ systems, and particularly, the central nervous system, the respiratory system, the gastrointestinal tract. The extreme variability of AIDS presentations requires a specific preparation and cooperation between the different diagnostic imaging specialists and a close collaboration with the clinicians. With AIDS, different morphologic and functional imaging techniques can be used for detection of disease sites, assessment of the extent of the disease and monitoring of disease changes over time and response to treatment. The complexity of AIDS presentations is such that full integration of the complementary information obtained with different techniques could be most useful. Image registration (coregistration, fusion) indicates approaches where precise spatial cross-references are obtained, in order to combine the information acquired with different imaging modalities, in particular by blending morphologic CT/MRI data with functional SPET/PET data. In this paper, an overview of the developments in the field of "image fusion" follows some comments on the results of morphologic and functional assessment of brain, chest and abdominal diseases in the course of AIDS, as illustrative examples of the potential benefits of multimodality image correlation.

AIDS-Related Opportunistic Infections↗
PubMed1995

Computed tomography and second-look surgery in ovarian cancer patients. Correlation, actual role and limitations of CT scan.

Computed tomography (CT scan) was performed on 58 clinically disease-free ovarian cancer patients. The scans were correlated with the results obtained at a subsequent second-look laparotomy. The sensitivity was 0.47, the specificity 0.87, diagnostic accuracy 0.63, positive predictive value 0.84 and negative 0.53. Undetected microscopic disease was classified as a false-negative result. Sensitivity was poor for omental, mesenteric and peritoneal implants and for bowel infiltration, good for lymphnodal involvement and abdominal mass and decisively good for intrahepatic and plenic metastases of ovarian cancer. Due to a still high false-negative rate a normal CT scan does not provide sufficiently accurate diagnostic information to replace a second-look laparotomy. But on the other hand, due to a high specificity, the usefulness of CT can be limited to approximately 27% of patients, with true-positive findings, who might have been saved surgical reexploration. Adjunct studies such as immunoscintigraphy with radiolabelled monoclonal antibodies and measurement of tumor markers further increase its diagnostic accuracy.

Female↗
PubMed1995

[Low-pressure transurethral prostatectomy. Personal experience and case series at the Urological Department of the Ospedale di Desenzano del Garda].

We report the experience of Urological Department of Desenzano del Garda by explaining strict indications and accurate technical approach. We indicate the useful employment of Reuter's trocar, with our results and complications. The Author support the actuality and validity of low-pressure TURP with good results and minimal invasiveness of this technique.

Evaluation Studies as Topic↗
PubMed1994

[Scintigraphy with gallium-67 citrate in patients with AIDS: pathologic extrapulmonary uptake].

67Gallium citrate can accumulate in different inflammatory and neoplastic lesions. The mechanisms of 67Gallium uptake in abnormal tissue are still partially unknown and the tracer is considered a nonspecific indicator of disease. In AIDS patients, 67Gallium citrate is used in the diagnosis and characterization of opportunistic pulmonary infections and especially of Pneumocystis carinii pneumonia. From June 1989 through December 1992 in our Department 140 67Gallium scans were performed on 103 AIDS patients, referred for evaluation of pulmonary symptoms. All studies were carried out 72 hours after i.v. administration of 185 MBq 67Gallium citrate, with anterior and posterior views of head, chest and abdomen. The images were evaluated with conventional diagnostic criteria and site, number and intensity of abnormal foci of extrapulmonary uptake were recorded. Abnormal extrapulmonary uptake was found in 17 patients (12%): gastric (3, two of which also exhibited abnormal intestinal uptake), esophageal (1) hepatic (1), intestinal (2) renal (4), nodal (3), ocular (1), cutaneous (1), sinusal (1) localizations. In all cases clinical, endoscopic, bioptic or microbiological demonstration of the possible cause of 67Gallium uptake was obtained. An intriguing finding in our series was the lower incidence of gastric uptake (two patients with miliary tuberculosis and one patient with gastric candidiasis) than in the literature. This finding could be explained by clinical and epidemiologic differences between different patient populations. However, the scan interval after tracer administration should be also taken into account, since in our study scans were always performed at 72 hours, while in other series the interval ranged 24-48 hours. The relatively high incidence of abnormal extrapulmonary uptake confirms the opportunity of whole body exploration after 67Gallium administration in the patients with such multisystemic disease as AIDS, even when the patients are referred mainly for respiratory problems.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Diagnostic evaluation of thyroid involvement by histiocytosis X.

UNLABELLED: We report the successful diagnosis of thyroid involvement by histiocytosis X due to accurate evaluation of nuclear medicine results. METHODS: A total thyroidectomy specimen from our patient was initially suggestive of medullary thyroid carcinoma. However, histologic reevaluation was performed on the basis of nuclear medicine findings which were incompatible with the original histologic diagnosis. RESULTS: Immunohistochemical and light microscopy studies were performed to obtain the correct diagnosis. Diffuse thyroid involvement by histiocytosis X was demonstrated. CONCLUSION: Thyroid scintigraphy was helpful in successfully diagnosing thyroid involvement by histiocytosis X. Because tracer uptake is related to increased cellularity and metabolism, none of these tracers reported here is specific for defining histiocytosis X.

3-Iodobenzylguanidine↗
PubMed1993

Identification of unique nuclear regulatory proteins for the insulin receptor gene, which appear during myocyte and adipocyte differentiation.

To define the molecular mechanism(s) that activate insulin receptor gene transcription during cell differentiation, we tested nuclear extracts from BC3H-1 muscle cells for their binding to the 5'-flanking region of the human insulin receptor gene. DNA binding activity of nuclear extracts was low in undifferentiated BC3H-1 cells and increased significantly during differentiation. Gel retardation assays, combined with DNase I footprinting, showed that the increased insulin receptor gene transcription occurring during differentiation was directly correlated with the appearance of DNA binding proteins that specifically interacted with two AT-rich sequences of the regulatory region of the insulin receptor gene. Fibroblast growth factor, a known inhibitor of the transcription of muscle-specific DNA binding proteins, did not inhibit the appearance of these insulin receptor DNA binding proteins. When 3T3-L1 cells differentiate from preadipocytes to adipocytes, insulin receptor gene transcription significantly increases. In differentiated adipocytes, the same two insulin receptor DNA binding proteins markedly increased. Reporter gene analysis with the two AT-rich sequences demonstrated that both of these regions of the insulin receptor gene had the characteristics of promoter rather than enhancer elements. Thus, these proteins interacting with these AT-rich sequences may have major importance in regulating the expression of the insulin receptor in target tissues.

3T3 Cells↗
PubMed1993

[Lung interstitial disease in systemic sclerosis: semiologic characteristics with high-resolution computerized tomography and comparison with other methods].

In 28 patients with systemic sclerosis interstitial lung involvement was investigated with high-resolution Computed Tomography (HRCT) in comparison with other diagnostic methods (respiratory function tests, lung scintigraphy and conventional radiography of the chest). The most frequent CT signs were: interlobular septal thickening, intralobular interstitial thickening, and ground-glass density. Their distribution was generally basal and posterior and high correlation was observed between the extent of lung disease and the cutaneous pattern of scleroderma. Pathological findings were present in 93% of cases: HRCT can must be considered more effective than the other methods in the evaluation of systemic sclerosis and should therefore be a fundamental diagnostic tool in the study and follow-up of interstitial diseases in the patients with systemic sclerosis.

Adult↗
PubMed1993

[Multiple metachronous metastasis of adenocarcinoma of the kidneys in crossed ectopy with fusion].

The A.A. report the clinic history of patient that showed up their examination with multiple metachronous arose fifteen months ago after a widening nephrectomy, by adenocarcinoma of ectopic-crossed kidney with fusion. They resume the pathogenetic and therapeutics hypothesis; in agreement on the prognostic difficulty and on the variability line of conduct by the kidney adenocarcinoma.

Adenocarcinoma↗
PubMed1992

Regulation of biological functions by an insulin receptor monoclonal antibody in insulin receptor beta-subunit mutants.

We investigated the effects of MA-5, a human-specific monoclonal antibody to the insulin receptor alpha-subunit, on transmembrane signaling in cell lines transfected with and expressing both normal human insulin receptors and receptors mutated in their beta-subunit tyrosine kinase domains. In cell lines expressing normal human insulin receptors, MA-5 stimulated three biological functions: aminoisobutyric acid (AIB) uptake, thymidine incorporation, and S6 kinase activation. Under conditions where these biological functions were stimulated, there was no detectable stimulation of receptor tyrosine kinase. We then combined the use of this monoclonal antibody with cells expressing insulin receptors with mutations in the beta-subunit tyrosine kinase domain; two of ATP binding site mutants V1008 (Gly----Val) and M1030 (Lys----Met) and one triple-tyrosine autophosphorylation site mutant F3 (Tyr----Phe at 1158, 1162, and 1163). In cells expressing V1008 receptors, none of the three biological functions of insulin was stimulated. In cells expressing M1030 receptors, AIB uptake was stimulated to a small, but significant, extent whereas the other two functions were not. In cells expressing F3 receptors, AIB uptake and S6 kinase activation, but not thymidine incorporation, were fully stimulated. The data suggest, therefore, that (1) activation of insulin receptor tyrosine kinase may not be a prerequisite for signaling of all the actions of insulin and (2) there may be multiple signal transduction pathways to account for the biological actions of insulin.

Aminoisobutyric Acids↗
PubMed1992

Growth factor receptor regulation in the Minn-1 leprechaun: defects in both insulin receptor and epidermal growth factor receptor gene expression.

Leprechaunism is a disorder characterized by intrauterine growth retardation, distinctive dysmorphology, and extreme insulin resistance due to structural abnormalities of the insulin receptor (IR). In addition to the IR, it has been suggested that abnormalities of the other growth factor receptors may occur in this syndrome. Using fibroblasts from the Minn-1 leprechaun, we have now investigated the expression of three different growth factor receptor genes: the IR, the insulin-like growth factor-I receptor (IGF-IR), and the epidermal growth factor receptor (EGFR). In agreement with previous studies, we found decreased insulin binding to fibroblasts from the Minn-1 leprechaun. In these cells, the IR transcription rate was not decreased, and sequence analysis of the IR promoter region of the patient showed no abnormalities. Both single-stranded conformational polymorphism analysis (SSCP) and DNA sequencing confirmed a previously reported nonsense mutation in one of the patient's two IR alleles at exon 14. mRNA levels for the IR were markedly decreased, suggesting that IR mRNA turnover was enhanced. We then studied the expression of the closely related IGF-IR Ligand binding, mRNA content, and transcription rate were all normal. In contrast to the IGF-IR, when the EGFR was studied, ligand binding and mRNA content were markedly decreased. These studies therefore raise the possibility that the phenotypic expression of leprechaunism results from defects in the expression of both the IR and the EGFR.

Abnormalities, Multiple↗