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Biomedical subjects

C Tosi

Publications and source records attributed to C Tosi.

At least 19 recordsLinked to original sources

[Endemic cholera in Chad: a real public health problem].

At the present time, cholera epidemics have become annual, even seasonal, events in Chad. This review of data obtained from a Division of the Sanitation Information System in Chad was carried out to determine the epidemiological profile and natural course of cholera in Chad and to propose preventive measures within the country's means. The main findings were that cholera epidemics start at the junction between the dry and rainy season (March to June), that they last for six months, and that peak incidence occurs 4 to 6 weeks after the first reported cases. The mortality rate is approximately 5 p. 100 depending on time and place. Two foci were located: one at Logone-Gana (Chari-Baguiri) and the other at Fianga (Mayo-Kebbi). These findings show that cholera is now endemic in Chad. A major implication of this study is that decentralized epidemiological surveillance should be set up with monitoring units located around endemic sites. Mortality could probably be lowered by better patient care at the beginning of the epidemic. Improvements in public hygiene, waste disposal, and water purification are needed.

Chad↗

Confocal microscopic localization of anti-myelin-associated glycoprotein autoantibodies in a patient with peripheral neuropathy initially lacking a detectable IgM gammopathy.

We report here on a patient with anti-myelin-associated glycoprotein (MAG) neuropathy in whom examination of a sural nerve biopsy by multichannel confocal microscopy showed a partly overlapping distribution of MAG and IgM deposits in myelinated fibers. Our data demonstrate that MAG in Schmidt-Lanterman incisures and paranodal loops, as well as some additional HNK-1-positive components of the basal lamina, are the major targets of the anti-MAG monoclonal IgM autoantibodies in this neuropathy in vivo. Perforation of the basal lamina can allow the penetration and binding of anti-MAG IgM inside myelinated fibers. Our results support and extend the notion that the production of monoclonal anti-MAG IgM may be antigenically driven by MAG molecules and that this process may occur in the immunologically privileged environment of the nerve prior to the appearance of a genuine gammopathy in serum.

Autoantibodies↗

[The assessment of skin tumors with magnetic resonance with high resolution and a paramagnetic contrast medium].

INTRODUCTION: The technologic improvement of surface coils in MRI has allowed better visualization of the skin and thus permitted the clinical use of this technique in dermatology. MRI allows to assess the depth and extent of skin tumors and to detect any malignant transformation. The MR differentiation between benign and malignant skin lesions relies on morphological criteria which however do not have an absolute diagnostic value. We investigated the role of paramagnetic contrast agents in the differentiation between benign and malignant skin lesions. MATERIAL AND METHODS: Forty-one patients, 33 with benign and 8 with malignant skin tumors, were submitted to MRI. All the examinations were performed with a 1.5 T superconductive unit, with a 2.5 cm surface coil. Axial T1- and T2-weighted SE images were acquired with 2 mm slice thickness. Paramagnetic contrast material was administered to all patients. The signal intensity of the skin lesions was calculated before and after paramagnetic contrast agent administration positioning a region of interest. A percentage ratio of contrast enhancement was calculated to quantify contrast agent uptake and the relative values were compared between benign and malignant lesions. A qualitative analysis was also performed rating the contrast enhancement of each lesion as high, intermediate, or absent. RESULTS: The quantitative analysis showed a statistically significant difference (p < .5) between the contrast enhancement values of benign and malignant lesions. In particular, malignancies had values ranging 117.3 (+/- 28.7) to 125 (+/- 32.4), while benign lesions had -20.6 to 99.8 (+/- 21.1). Conversely, no difference in contrast enhancement was found at qualitative analysis. CONCLUSIONS: MRI is a promising tool for characterizing skin tumors. Our preliminary results should be confirmed on larger series of patients with the use of high temporal resolution imaging sequences.

Adolescent↗

Engineering of peptide synthetases. Key role of the thioesterase-like domain for efficient production of recombinant peptides.

Peptide synthetases are large enzymatic complexes that catalyze the synthesis of biologically active peptides in microorganisms and fungi and typically have an unusual structure and sequence. Peptide synthetases have recently been engineered to modify the substrate specificity to produce peptides of a new sequence. In this study we show that surfactin synthetase can also be modified by moving the carboxyl-terminal intrinsic thioesterase region to the end of the internal amino acid binding domains, thus generating strains that produce new truncated peptides of the predicted sequence. Omission of the thioesterase domain results in nonproducing strains, thus showing the essential role of this region and the possibility of obtaining peptides of different lengths by genetic engineering. Secretion of the peptides depends on the presence of a functional sfp gene.

Amino Acid Sequence↗

[Thoracic actinomycosis with lung, mediastinal and pericardial involvement. A case report].

A case of actinomycosis is reported in a 17-years-old woman with pleural and pericardial effusions and anterior mediastinal mass. Histopathological diagnosis of actinomycosis was performed by mediastinal mass biopsy. There was no evidence of immunodeficit or neoplasia. Probably a dental manipulation favoured the Actinomyces infection. Treatment with antibiotics resulted in a reduction of mediastinal mass and in a complete resolution of pleural and pericardial effusions.

Actinomycosis↗

Thyroid ultrasonography in patients with a previous episode of amiodarone induced thyrotoxicosis.

Amiodarone induced thyrotoxicosis (AIT) occurs most frequently in euthyroid patients with nodular goiter or Graves' disease due to release of iodine from this iodine rich drug. However, some cases of AIT have been attributed to an inflammatory process of the thyroid gland due to amiodarone itself. We have studied the echographic pattern of the thyroid in 11 euthyroid patients who had an episode of AIT 32.4 +/- 3.6 months earlier due to amiodarone induced thyroiditis. There was a significant increase in dyshomogeneous echo patterns and hyperechogenecity which suggests fibrotic lesions. These findings were similar to those observed in 10 euthyroid patients who 77 +/- 12 months earlier had an episode of subacute thyroiditis (SAT). Thyroid volumes of control subjects and patients with a history of AIT and SAT were 10.9 +/- 1.4, 8.7 +/- 1.4 and 9.8 +/- 1.7, in the order. These values were not significantly different. These echographic findings, normal serum thyroid hormone and TSH concentrations and the absence of circulating antithyroid peroxidase antibodies suggest that underlying thyroid autonomy and Graves' disease were not the cause of the previous episode of AIT. The presence of hyperechogenic and dyshomogeneous patterns appears the result of the healing of the inflammatory AIT process.

Adult↗

Restoration of gait with orthoses in thoracic paraplegia: a multicentric investigation.

Twenty-eight patients with complete T3-12 traumatic paraplegia were fitted with hip guidance orthosis (HGO, four cases), reciprocating gait orthosis (RGO, 13 cases) or advanced reciprocating gait orthosis (ARGO, 11 cases). Patients were enrolled for 2 months-6 years (median 5 months) in six Italian rehabilitation centres engaged in a common prospective protocol, including a 6 month follow up. After 12-84 (median 20) rehabilitation sessions over a 3-16 week (median 7) period of specific training all of the patients could perform don-doff manoeuvres autonomously in 2.5-15 min (median 6.4), and could walk at least 30 m with a walker (15 cases) or forearm crutches (13 cases) at 10-50 cm/s (median 16.6). HGO patients tended to walk more slowly than the others. None of them could walk upstairs, while three out of 13 RGO patients and seven out of 11 ARGO patients could. Six months later, 21 patients still used the orthosis for 0.5-3 h daily (median 2). Only four patients used the orthosis to walk outdoors. As a median they could still attain the speed recorded at discharge. Six patients had decided to abandon the device, while one was wheelchair bound due to a recent spinal intervention. Neither clinical, demographic or locomotor variables, nor centre and type of orthosis appeared to be predictive of abandonment of the device. During either the training or the follow up periods, six out of 13 RGO and seven out of 11 ARGO had to be repaired by the orthotist 1-10 times (median 3). Thus, in our sample of paraplegics, walking with these orthoses appeared to be a promising form of exercise rather than an alternative to wheelchair locomotion.

Adolescent↗

Echographic diagnosis of pretibial myxedema in patients with autoimmune thyroid disease.

In the present study we have evaluated the use of pretibial ultrasound for the diagnosis of pretibial myxedema (PTM). We studied 76 patients, 58 with Graves' disease, 13 with Hashimoto's thyroiditis and five with idiopathic hypothyroidism. Thirty-two normal subjects were also studied as controls. Sixty-four patients had associated ophthalmopathy. The ultrasound scanner was equipped with 10- and 13-MHz probes. Punch biopsies were carried out in 11 patients and tissue sections examined on a light microscope. On clinical examination 21 patients (28%) had suspected PTM. By ultrasound, we measured the thickness of dermis and subcutaneous tissue (D1) and that including only deeper dermis (D2) in normal subjects to define the echographic parameters of normal pretibial skin. We then found increased skin thickness in 25 patients (33%), with mean D1 and D2 values significantly higher than those measured in controls (p < 0.00001). The echographic study was positive in 20 patients with ophthalmopathy (31%). Ultrasound showed increased skin thickness in 16 of 21 patients (76%) with clinically suspected PTM. Histopathological findings confirmed the presence of PTM in all the patients who underwent pretibial skin biopsy. We believe that the measurement of pretibial skin thickness by ultrasound may be useful for revealing the presence of PTM.

Adult↗

[Role of echo-color Doppler in the monitoring of the transplanted kidney].

Renal allografts are subject to many vascular complications. Doppler US is a non-invasive technique that can evaluate many of the potential complications related to renal allografts, such as rejection, cyclosporine toxicity, acute tubular necrosis, renal artery stenosis, renal vein thrombosis. Changes in the resistive index (RI), which accurately reflects renal vascular impedance, have been employed in the evaluation of renal allograft dysfunction. A review of the literature shows conflicting results with values of sensitivity and specificity ranging from 0.96 and 0.97 to 0.46 and 0.80, respectively. It seems that an increase in the RI is a nonspecific sign in determining the underlying abnormality due to the unique features of the vascular bed of each allograft which results in poor correlative values for single isolated measurements of RI. Serial studies, employing a baseline value, can be useful in the follow-up of graft dysfunction.

Color↗

Effects of bezafibrate on biosynthesis of cholesterol and on degradation of native and acetylated low-density lipoproteins in incubated human monocytes.

The effects of bezafibrate on 14C-acetate incorporation into non-saponifiable lipids and on degradation of native and acetylated [125I] low-density lipoproteins (LDL) in cultured human monocytes has been evaluated. The presence of bezafibrate in the incubation medium resulted in a decrease of labelled acetate incorporation into non-saponifiable lipids. In parallel with the decrease in sterol synthesis, bezafibrate produced an increase in total and specific degradation of native low-density lipoproteins, whereas the degradation of acetylated low-density lipoproteins was not affected by the drug. These data, though obtained with concentrations of bezafibrate in the incubation medium greater than those encountered in ordinary therapeutic conditions, support the hypothesis that bezafibrate inhibits cholesterol biosynthesis and increases removal of low-density lipoproteins by activating the specific receptor pathway.

Bezafibrate↗

Apolipoprotein AIMilano. Disulfide-linked dimers increase high density lipoprotein stability and hinder particle interconversion in carrier plasma.

The in vitro metabolism of high density lipoproteins (HDL) in carriers of the apolipoprotein AIMilano (apoAIM) mutant was investigated during incubation of whole plasma and isolated lipoprotein fractions. A reduced cholesterol esterification (16.5 versus 25.0% for controls) and a decreased exchange of lipids between HDL and lower density lipoproteins was observed during incubation (6 h at 37 degrees C) of AIM plasma. Control HDL3 were converted to larger, faster-floating HDL particles, whereas only a fraction of AIM HDL3 followed the same pathway. Incubations were also carried out by mixing HDL3 from controls and AIM carriers with a lipoprotein-depleted plasma fraction in the presence of triglyceride-rich particles isolated from Intralipid. AIM HDL3 again showed a reduced capacity for lipid exchange; some HDL3 particles followed a "normal" conversion to faster-floating, larger HDL, whereas the small AIM HDL3 were not modified, indicating that AIM HDL3 are a mixture of metabolically functional and nonfunctional particles. Following transformation of the apoAIM homo- and heterodimers into their normal counterparts, i.e. monomeric apoAI and -AII, by reduction and carboxamidomethylation of AIM HDL3, the modified HDL3 behave like control HDL3 during incubation with lipoprotein-depleted plasma and triglyceride-rich particles. The presence of AIM dimers is most likely responsible for the increased HDL3 stability in the AIM carriers, indicating that apolipoprotein composition plays a major role in HDL particle interconversion.

Apolipoprotein A-I↗

RIECA: an innovative immuno enzymatic competition assay for apolipoproteins AI and B determination.

The authors describe the production, via recombinant DNA technology, of bifunctional polypeptides for immunoenzymatic assays. These molecules contain an apolipoprotein moiety fused to an active beta-galactosidase enzyme, and are used as tracers in competition assays with specific monoclonal antibodies. The final colorimetric result is inversely correlated with the apolipoproteins plasma values. This technology, named RIECA (Recombinant Immunoenzymatic Competition Assay) is very accurate and flexible and may be applied to a wide range of diagnostic interest.

Antibodies, Monoclonal↗

Structure and molecular orbital study of ergoline derivatives. 1-(6-Methyl-8 beta-ergolinylmethyl)imidazolidine-2,4-dione (I) and 2-(10-methoxy-1,6-dimethyl-8 beta-ergolinyl)ethyl 3,5-dimethyl-1H-2-pyrrolecarboxylate toluene hemisolvate (II) and comparison with nicergoline (III).

(I): C19H22N4O2 (Registry No. 95688-34-9), m.p. greater than 573 K, Mr = 338.4, orthorhombic, P2(1)2(1)2(1), a = 8.392 (2), b = 13.004 (2), c = 15.676 (5) A, V = 1710.7 (7) A3, Z = 4, Dx = 1.31 Mg m-3, Mo Ka radiation, lambda = 0.71069 A, mu = 0.08 mm-1, F(000) = 720, T = 293 K, final R = 0.051 for 990 independent reflexions. (II): C26H33N3O3.1/2C7H8 (Registry No. 54370-23-9), m.p. 427-429 K, Mr = 481.64, monoclinic, P2(1), a = 11.595 (4), b = 14.274 (2), c = 16.103 (4) A, beta = 100.19 (3) degrees, V = 2623 (1) A3, Z = 4, Dx = 1.22 Mg m-3, Mo Ka radiation, lambda = 0.71069 A, mu = 0.07 mm-1, F(000) = 1036, T = 293 K, final R = 0.064 for 2738 independent reflexions. Two independent molecules constitute the asymmetric unit, together with a toluene molecule. Parallel investigations of the title compounds by single-crystal X-ray analysis and theoretical calculations have converged in showing an extended configuration of the side chain attached at the C8 atom of the ergoline nucleus.

Chemical Phenomena↗

[Can one use high thoracic epidural analgesia in postoperative intensive care of the myasthenia patient following trans-sternal thymectomy?].

Analgesia is an important problem in myasthenia gravis patients who have undergone transsternal thymectomy. Postoperative pain interferes with pulmonary function, which is already limited by the disease. The choice of medication is restricted because many analgesics are synergic to the myasthenia gravis syndrome and detrimental to the patient. Three patients with severe myasthenia gravis are presented who had undergone transsternal thymectomy with good postoperative results. They received high thoracal epidural anesthesia (C7-Th1/Th1-Th2/Th2-Th3) with a solution of bupivacaine and morphine (20 ml 0.25% bupivacaine with 10% morphine). The patients were extubated in the first 48 hours and monitoring of respiratory function (CV2, PO2, PCO2) showed satisfactory values. With this type of analgesia we obtained early mobilization and good patient cooperation. Although limited this favourable experience confirms that high thoracal epidural anesthesia is a sure technique which allows rapid weaning from the ventilator and maximum comfort for the patient. It avoids the use of other medication or analgesics which are contraindicated in these patients.

Adult↗

Reduced HDL2 levels in myocardial infarction patients without risk factors for atherosclerosis.

Out of a total of 170 patients with a first myocardial infarction, aged below 65 years, consecutively admitted to the Coronary Care Unit of a large urban hospital, only 14 did not present with any risk factor(s) for atherosclerosis (smoking, hypertension, diabetes and obesity). None of these 14 patients showed significant hyperlipidemia. Compared to a control series of normal individuals of the same age (50.0 +/- 5.8 years for males and 61.6 +/- 3.0 years for females), they showed a significant reduction of high-density lipoprotein (HDL)-cholesterol and of apolipoprotein A-I (respectively -18.2 and -9.5%). However, the most striking abnormality was a 30% decrease of the HDL2 mass and of HDL2 cholesterol; both HDL2 and HDL3 had a reduced cholesteryl ester content in the patients. Reduced HDL2 mass and cholesterol levels in plasma, accompanied by significant alterations in HDL subfraction composition, are consistent with a defective cholesterol esterification in HDL. HDL2 deficiency may be a primary alteration in myocardial infarction patients without other significant risk factors.

Arteriosclerosis↗