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Biomedical subjects

M Zanetti

Publications and source records attributed to M Zanetti.

At least 55 records · Page 3Linked to original sources
PubMed2000

Functional MR imaging of the craniocervical junction. Correlation with alar ligaments and occipito-atlantoaxial joint morphology: a study in 50 asymptomatic subjects.

PURPOSE: Whiplash injuries are frequent in industrialized countries. The acute and chronic symptoms following such injuries are incompletely understood and objective clinical or imaging findings are rare. Several authors have suspected that rear end collisions occurring when the head is rotated may result in tears of the alar ligaments. There has been experimental proof that a torn alar ligament increases the rotation of the C0/C1 and C1/C2 segments to the contralateral side. Functional cross sectional imaging has therefore been proposed to diagnose injuries of the alar ligaments. So far, published data on normal ranges of rotation in an asymptomatic population have been sparse. The aim of this study was to determine by MR imaging the normal range of rotation in the first three cervical segments and their relation to the morphology of the alar ligaments and the occipito-atlantoaxial joints. MATERIAL AND METHODS: Functional MR imaging of the craniocervical junction in maximum active left and right head rotation was performed in 50 healthy volunteers with a mean age of 29.8 years (31 men, 19 women, range 19-47 years). Measurements were independently performed by two musculoskeletal radiologists to assess interobserver error. The results were correlated with gender and age, with morphological findings in the occipito-atlantoaxial joints (i.e. joint symmetry, joint effusions, dens position), and with the form, course and symmetry of the alar ligaments. RESULTS: The mean range of rotation for the C0/C1 joint was 2.7 degrees (standard deviation [SD] 3.3 degrees)/3.3 degrees (SD 3.6 degrees) (right/left) and at the C1/C2 level 38 degrees (SD 6.5 degrees)/37.8 degrees (SD 6.4 degrees). The mean differences in left/right rotation were: C0/C1 3.5 degrees (SD 2.8 degrees) and C1/C2 6.3 degrees (SD 4.4 degrees). No correlation was found between segmental rotation and morphological characteristics of the craniocervical joints or ligament structures. CONCLUSION: There is wide variation of segmental motion in the upper cervical spine. Differences in right-to-left rotation are frequently encountered in an asymptomatic population. Therefore, these measurements are unsuitable for indirect diagnosis of soft tissue lesions after whiplash injury and should not be used as a basis for treatment guidelines.

Adult↗
PubMed2000

Cytotoxic T cell immunity against telomerase reverse transcriptase in humans.

Telomerase is a ribonucleoprotein enzyme which has been linked to malignant transformation in human cells. Telomerase activity is increased in the vast majority of human tumors, making its gene product the first molecule common to all human tumors. The generation of endogenously processed telomerase peptides bound to Class I MHC molecules could therefore target cytotoxic T lymphocytes (CTL) to tumors of different origins. This could advance vaccine therapy against cancer provided that precursor CTL recognizing telomerase peptides in normal adults and cancer patients can be expanded through immunization. We demonstrate here that the majority of normal individuals and patients with prostate cancer immunized in vitro against two HLA-A2.1 restricted peptides from telomerase reverse transcriptase (hTRT) develop hTRT-specific CTL. This suggests the existence of precursor CTL for hTRT in the repertoire of normal individuals and in cancer patients. Most importantly, the CTL of cancer patients specifically lysed a variety of HLA-A2(+) cancer cell lines, demonstrating immunological recognition of endogenously processed hTRT peptides. Moreover, in vivo immunization of HLA-A2.1 transgenic mice generated a specific CTL response against both hTRT peptides. Based on the induction of CTL responses in vitro and in vivo, and the susceptibility to lysis of tumor cells of various origins by hTRT CTL, we suggest that hTRT could serve as a universal cancer vaccine for humans.

Adult↗
PubMed2000

Structural features and biological activities of the cathelicidin-derived antimicrobial peptides.

Cathelicidins are a numerous group of mammalian proteins that carry diverse antimicrobial peptides at the C-terminus of a highly conserved preproregion. These peptides, which become active when released from the proregion, display a remarkable variety of sizes, sequences, and structures, and in fact comprise representatives of all the structural groups in which the known antimicrobial peptides have been classified. Most of the cathelicidin-derived peptides exert a broad spectrum and potent antimicrobial activity and also bind to lipopolysaccharide and neutralize its effects. In addition, some of them have recently been shown to exert other activities and might participate in host defense also by virtue of their ability to induce expression of molecules involved in a variety of biological processes. This review is aimed at providing a general overview of the cathelicidins and of the peptides derived therefrom, with emphasis on aspects such as structure, biological activities in vitro and in vivo, and structure/activity relationship studies.

Amino Acid Sequence↗
PubMed2000

Gene transfer of endothelial nitric oxide synthase alters endothelium-dependent relaxations in aortas from diabetic rabbits.

AIMS/HYPOTHESIS: Cardiovascular disease is the leading cause of death in diabetes mellitus. Abnormal endothelium-dependent relaxation is observed both in humans and in animal models of diabetes mellitus and decreased bioavailability of nitric oxide (NO) is thought to be involved in this defect. Therefore, the aim of this study was to test whether adenovirus-mediated gene transfer of endothelial nitric oxide synthase (eNOS) alters vascular reactivity of diabetic vessels. METHODS: Vascular reactivity was first assessed in thoracic aortas and carotid arteries from nine alloxan-induced diabetic (plasma glucose, 26.5 +/- 1.2 mmol/l; HbA1c, 6.4 +/- 0.3%) and nine control rabbits (plasma glucose, 11.1 +/- 1.3 mmol/l; HbA1c, 2.1 +/- 0.1%). Vascular reactivity was next examined in thoracic aortas of diabetic animals after ex vivo transduction with replication-deficient adenovirus encoding gene for eNOS (AdeNOS) or beta-galactosidase (Ad beta gal). RESULTS: After 10 weeks of hyperglycaemia, endothelium-dependent relaxation to acetylcholine was impaired in diabetic aorta, but was normal in carotid arteries from diabetic rabbits. In contrast, responses of both vessels to calcium ionophore and nitric oxide donor were normal. Histochemical staining for beta-galactosidase and immunohistochemistry for eNOS showed transgene expression in the endothelium and adventitia in Ad beta gal and AdeNOS transduced vessels, respectively. During submaximum contractions with phenylephrine, relaxations to low concentrations of acetylcholine (3 x 10(-8) to 10(-7) mol/l) were augmented in AdeNOS transduced diabetic vessels. CONCLUSION/INTERPRETATION: These findings suggest that adenovirus-mediated gene transfer of eNOS to diabetic aorta alters vascular reactivity.

Animals↗
PubMed2000

Spontaneous osteonecrosis of the medial compartment of the knee: a MRI follow-up after conservative and operative treatment, preliminary results.

Symptoms in patients suffering from spontaneous osteonecrosis of the knee (SONK) may be reduced by high tibial osteotomy (HTO). However, the fate of the necrotic lesion is unknown and needs further investigation. We conducted a prospective study to evaluate magnetic resonance imaging (MRI) changes after operative and nonoperative treatment. Ten consecutive patients suffering from SONK of the medial compartment were given two treatment options: either HTO (n = 6) or conservative treatment with partial weight bearing for 3 months (n = 4). We measured the greatest extent of well-defined subchondral low signal intensity abnormality, considered to represent necrosis, and the surrounding area of intermediate signal intensity, considered to represent perifocal bone marrow edema, on T1-weighted coronal MRI images before and after treatment. The MRI follow-up period was 17.5 months (range 12-27) in the HTO group and 14.5 months (range 8-25) in the nonoperative group. At follow-up the MRI evaluation revealed a decrease in the low signal intense areas (necrosis) in five of the six patients in the HTO group. Only one of the four nonoperative patients showed a decrease in the low signal intense area. The intermediate intense areas (edema) decreased in all patients in the HTO group and in three of four in the nonoperative group. The mean decrease in the area of perifocal edema was significantly greater in the HTO group than in the nonoperative group (P = 0.019). No statistically significant difference was found for the area of necrosis between the two groups (P = 0.171). A clinical improvement was observed in all patients of the HTO group but in only two of the four patients of the nonoperative group. We conclude that the decrease in perifocal bone marrow edema seems to be associated with improved patient comfort. The MRI appearance of the necrotic lesion does not alter with either treatment mode.

Aged↗
PubMed2000

MR imaging after rotator cuff repair: full-thickness defects and bursitis-like subacromial abnormalities in asymptomatic subjects.

OBJECTIVE: To determine the prevalence and extent of residual defects or retears and bursitis-like subacromial abnormalities on MR images after rotator cuff repair in asymptomatic subjects, and to define the clinical relevance of these findings. DESIGN AND PATIENTS: Fourteen completely asymptomatic patients and 32 patients with residual symptoms were investigated 27-53 months (mean 39 months) after open transosseous reinsertion of the rotator cuff. Coronal T2-weighted turbo spin-echo and turbo STIR or T2-weighted fat-suppressed MR images were obtained. The prevalence and extent of residual defects or retears of the rotator cuff and bursitis-like subacromial abnormalities were determined. RESULTS: Residual defects or retears were detected in three (21%) and bursitis-like abnormalities in 14 (100%) of the 14 asymptomatic patients. Fifteen (47%) residual defects or retears and 31 (97%) bursitis-like abnormalities were diagnosed in the 32 patients with residual symptoms. The size of the residual defects/retears was significantly smaller in the asymptomatic group (mean 8 mm, range 6-11 mm) than in the symptomatic group (mean 32 mm, range 7-50 mm) (t-test, P = 0.001). The extent of the bursitis-like subacromial abnormalities did not significantly differ (t-test, P > 0.05) between asymptomatic (mean 28 x 3 mm) and symptomatic patients (mean 32 x 3 mm). CONCLUSION: Small residual defects or retears (< 1 cm) of the rotator cuff are not necessarily associated with clinical symptoms. Subacromial bursitis-like MR abnormalities are almost always seen after rotator cuff repair even in patients without residual complaints. They may persist for several years after rotator cuff repair and appear to be clinically irrelevant.

Adult↗
PubMed2000

Posterior glenoid rim deficiency in recurrent (atraumatic) posterior shoulder instability.

OBJECTIVE: To assess the shape of the posterior glenoid rim in patients with recurrent (atraumatic) posterior instability. DESIGN AND PATIENTS: CT examinations of 15 shoulders with recurrent (atraumatic) posterior instability were reviewed in masked fashion with regard to abnormalities of the glenoid shape, specifically of its posterior rim. The glenoid version was also assessed. The findings were compared with the findings in 15 shoulders with recurrent anterior shoulder instability and 15 shoulders without instability. For all patients, surgical correlation was available. RESULTS: Fourteen of the 15 (93%) shoulders with recurrent (atraumatic) posterior shoulder instability had a deficiency of the posteroinferior glenoid rim. In patients with recurrent anterior instability or stable shoulders such deficiencies were less common (60% and 73%, respectively). The craniocaudal length of the deficiencies was largest in patients with posterior instability. When a posteroinferior deficiency with a craniocaudal length of 12 mm or more was defined as abnormal, sensitivity and specificity for diagnosing recurrent (atraumatic) posterior instability were 86.7% and 83.3%, respectively. There was a statistically significant difference in glenoid version between shoulders with posterior instability and stable shoulders (P=0.01). CONCLUSION: Recurrent (atraumatic) posterior shoulder instability should be considered in patients with a bony deficiency of the posteroinferior glenoid rim with a craniocaudal length of more than 12 mm.

Adolescent↗
PubMed2000

Imaging of degenerative and posttraumatic disease in the shoulder joint with ultrasound.

This article reviews the examination technique of shoulder ultrasound, normal and abnormal ultrasound findings in acute (posttraumatic) and chronic (degenerative) lesions. Moreover, it reviews the effectiveness of ultrasound in relation to magnetic resonance (MR) imaging. Most authors report that full-thickness tears of the supraspinatus can reliably be diagnosed by ultrasound. However, the simple diagnosis of a full-thickness rotator cuff tear is no longer sufficient for surgical management. The precise localization and size of rotator cuff tears as well as the extent of muscle degeneration is important for surgical planning. For this aspect and for partial-thickness tears of the supraspinatus, for subscapularis lesions as well as for lesions of the long biceps tendons there is no consensus regarding the diagnostic value of ultrasound. To the present, ultrasound (contrary to MR imaging) has failed to demonstrate that it consistently influences the clinician's degree of confidence in the clinical diagnosis or the treatment plan. Therefore, some orthopedic surgeons prefer MR imaging to ultrasound in the evaluation of rotator cuff tears and other abnormalities of the glenohumeral joint. Moreover, MR imaging, especially when combined with arthrography, represents a one-step investigation, which not only allows for assessment of rotator cuff lesion but also of lesions of the labrum (Bankart lesions, SLAP lesions), the joint capsule and the biceps tendon. It also demonstrates muscle atrophy, which represents an important predictor of surgical outcome in rotator cuff repair.

Diagnosis, Differential↗
PubMed2000

Microchimerism does not induce tolerance after in utero transplantation and may lead to the development of alloreactivity.

In utero transplantation is a new technology that may provide non-toxic treatment for congenital disorders. However, a decade of research on in utero transplantation has demonstrated a low degree of chimerism and tolerance in small and large animal models as well as in human beings. We hypothesized that if large numbers of purified stem cells/progenitors were injected, a higher degree of tolerance would be induced. We have performed a 2-year experiment designed to study chimerism and tolerance after in utero transplantation with large numbers of cytokine-recruited C-kit+ cells. Chimerism in the blood and tissues was tested through the lifespan of the animals, and in vitro immunologic assays were performed at the end of life. C-kit+ cells obtained from the peripheral blood of C57BL/6 mice were injected intraperitoneally into 12- to 13-day-old Balb/c murine fetuses. The injected populations contained 5% to 20% of Sca-1+ and 1% to 5% of CD3+ cells. Twenty-three percent of mice that received transplants showed circulating donor cells in the blood, and 7% to 14% showed donor cells in the tissues. The percent of donor cells in the blood and tissues was low (<0.01%). Timing of injection or cell dose did not affect chimerism or tolerance. Fifty percent (13 of 26) showed accelerated skin graft rejection and 5 of 26 (19%) had prolonged acceptance as compared with control mice not receiving transplants in utero. All mice that rejected skin grafts showed significantly increased natural killer function as compared with the mice with delayed graft acceptance. Fifty percent of tested recipient mice showed reactivity against donor cells in the cytotoxicity assay, which could be related to the prenatal sensitization. We conclude that microchimerism does not lead to the induction of a high degree tolerance after in utero transplantation and instead may lead to the development of alloreactivity to donor cells.

Animals↗
PubMed2000

Positional MR imaging of the lumbar spine: does it demonstrate nerve root compromise not visible at conventional MR imaging?

PURPOSE: To evaluate whether positional magnetic resonance (MR) images of the lumbar spine demonstrate nerve root compromise not visible on MR images obtained with the patient in a supine position (conventional MR images). MATERIALS AND METHODS: Thirty patients with chronic low back pain unresponsive to nonsurgical treatment and with disk abnormalities but without compression of neural structures were included. Positional MR images were obtained by using an open-configuration, 0.5-T MR imager with the patients seated and with flexion and extension of their backs. The disk and nerve root were related to the body position. Nerve root compression and foraminal size were correlated with the patient's symptoms, as assessed with a visual analogue scale. RESULTS: Nerve root contact without deviation was present in 34 of 152 instances in the supine position, in 62 instances in the seated flexion position, and in 45 instances in the seated extension position. As compared with the supine position, in the seated flexion position nerve root deviation decreased from 10 to eight instances; in the seated extension position, it increased from 10 to 13 instances. Nerve root compression was seen in one patient in the seated extension position. Positional pain score differences were significantly related to changes in foraminal size (P =.046) but not to differences in nerve root compromise. CONCLUSION: Positional MR imaging more frequently demonstrates minor neural compromise than does conventional MR imaging. Positional pain differences are related to position-dependent changes in foraminal size.

Adult↗
PubMed2000

Bone marrow edema pattern in osteoarthritic knees: correlation between MR imaging and histologic findings.

PURPOSE: To correlate magnetic resonance (MR) images of a bone marrow edema pattern with histologic findings in osteoarthritic knees. MATERIALS AND METHODS: Sixteen consecutive patients (age range, 43-79 years; mean, 67 years) referred for total knee replacement were examined with sagittal short inversion time inversion-recovery (STIR) and T1- and T2-weighted turbo spin-echo MR imaging 1-4 days before surgery. Tibial plateau abnormalities on MR images were compared quantitatively with those on histologic maps. RESULTS: The bone marrow edema pattern zone (ill-defined and hyperintense on STIR images and hypointense on T1-weighted MR images) mainly consisted of normal tissue (53% of the area was fatty marrow, 16% was intact trabeculae, and 2% was blood vessels) and a smaller proportion of several abnormalities (bone marrow necrosis [11% of area], abnormal [necrotic or remodeled] trabeculae [8%], bone marrow fibrosis [4%], bone marrow edema [4%], and bone marrow bleeding [2%]). The bone marrow edema pattern zone and the zone with a normal MR imaging appearance differed significantly in the presence of bone marrow necrosis (P =.021), bone marrow fibrosis (P =.014), and abnormal trabeculae (P =.011) but not in the prevalence of bone marrow edema (P =.069). Bone marrow edema also was found in zones with an unremarkable MR appearance (perifocal zone, 5% edema; control zone, 2% edema). CONCLUSION: A bone marrow edema pattern in osteoarthritic knees represents a number of noncharacteristic histologic abnormalities. Edema is not a major constituent of MR imaging signal intensity abnormalities in such knees.

Adult↗
PubMed2000

Characteristics of triangular fibrocartilage defects in symptomatic and contralateral asymptomatic wrists.

PURPOSE: To characterize triangular fibrocartilage (TFC) defects in symptomatic and contralateral asymptomatic wrists. MATERIALS AND METHODS: Communicating and noncommunicating defects of the TFC were depicted on bilateral wrist arthrograms in 56 patients with unilateral wrist pain and without associated lesions of the scapholunate or lunotriquetral ligaments. The exact location of each TFC lesion was noted. RESULTS: Communicating defects were noted in 36 (64%) of 56 symptomatic and in 26 (46%) of 56 asymptomatic wrists. Twenty-five (69%) of 36 communicating defects were bilateral. Except for one defect in each group of symptomatic and asymptomatic wrists, all communicating defects were noted radially. Noncommunicating defects were noted in 28 (50%) of 56 symptomatic wrists and in 15 (27%) of 56 asymptomatic wrists. Eleven (39%) of 28 noncommunicating defects were bilateral. On the symptomatic side, 28 of 36 noncommunicating defects (including eight multiple defects) were located proximally at the ulnar side. On the asymptomatic side, 11 of 17 noncommunicating defects (including two multiple defects) were at or near the ulna. CONCLUSION: Noncommunicating TFC defects, which typically are located on the proximal side of the TFC near its ulnar attachment, have a more reliable association with symptomatic wrists than do communicating defects. Radial-sided communicating defects described in the literature (Palmer type 1A and 1D) as posttraumatic commonly are seen bilaterally and in asymptomatic wrists.

Adolescent↗
PubMed2000

Femoral trochlear dysplasia: MR findings.

PURPOSE: To establish quantitative and qualitative magnetic resonance (MR) criteria for the diagnosis of trochlear dysplasia. MATERIALS AND METHODS: MR images were analyzed in 16 consecutive patients with and 23 without trochlear dysplasia. The standard of reference was a true lateral radiograph of the knee. Quantitative and qualitative MR criteria were assessed. RESULTS: In patients with trochlear dysplasia, the trochlear groove was significantly less deep than that in control subjects. The most accurate measurement was 3 cm above the femorotibial joint space (P: <.001), where a trochlear depth of 3 mm or less had a sensitivity of 100% and a specificity of 96%. The ventral trochlear prominence between the supratrochlear femoral cortex and the most ventral point of the trochlear floor (midsagittal section) was always larger than 6.9 mm in dysplastic trochleae. A facet ratio of less than 2:5 (medial to lateral) 3 cm above joint space level had a sensitivity of 100% and a specificity of 96%. A nipplelike anterior prominence at the superior end of the femoral trochlea on midsagittal images was a specific (91%) qualitative criterion. CONCLUSION: Dysplasia of the femoral trochlea can be diagnosed reliably by using quantitative or qualitative criteria on midsagittal or transverse MR images obtained 3 cm above the femorotibial joint space.

Adolescent↗
PubMed2000

Increased fibrinogen production in type 2 diabetic patients without detectable vascular complications: correlation with plasma glucagon concentrations.

Fibrinogen is a strong cardiovascular risk factor in the general population, and increased fibrinogen plasma concentrations have been reported in type 2 diabetic patients. However, the mechanisms leading to hyperfibrinogenemia in type 2 diabetes are not known. It is also not known whether possible alterations of fibrinogen turnover may precede clinical diabetic micro- and macrovascular complications and therefore potentially contribute to their onset. To address these questions, fibrinogen production was determined in six male type 2 diabetic patients without detectable micro- and macrovascular complications (age, 45 +/- 4 yr; body mass index, 27 +/- 0.9 kg/m2) and in seven nondiabetic matched controls using leucine isotope precursor-product relationships. Plasma glucose (P < 0.001), insulin (P < 0.05), and glucagon concentrations (P < 0.01) were increased in the patients. Diabetic patients also had increased plasma fibrinogen concentration (+ approximately 50%; P < 0.01) and pool (+ approximately 40%; P < 0.01) as well as fractional (+ approximately 35%; P = 0.08) and absolute (+ approximately 100%; P < 0.01) synthetic rates. The plasma glucagon concentration was positively related (P < 0.005 or less) to the fibrinogen concentration as well as to fractional and absolute synthetic rates. Thus, fibrinogen production is markedly enhanced, and this alteration is likely to determine the observed hyperfibrinogenemia in type 2 diabetic patients. Hyperglucagonemia may contribute to the increased fibrinogen production. These findings in normoalbuminuric patients without clinical complications support the hypothesis that increased fibrinogen production and plasma concentrations may precede and possibly contribute to the onset of clinical cardiovascular complications in type 2 diabetes.

Adult↗
PubMed2000

Subacute subdural haematoma complicating lumbar microdiscectomy.

There have been no previous reports of a spinal subdural haematoma occurring as a complication of spinal surgery. We highlight the pitfalls in the diagnosis and management of a subacute subdural haematoma resulting from a dural tear which occurred as a surgical complication of microdiscectomy.

Aged↗