Biomedical subjects

A Rovira

Publications and source records attributed to A Rovira.

At least 55 records · Page 3Linked to original sources

PubMed2000

One year follow up study of primary and transitional progressive multiple sclerosis.

OBJECTIVE: To document clinical and magnetic resonance imaging (MRI) characteristics of a large cohort of primary and transitional progressive multiple sclerosis (PP and TP MS) patients over one year. INTRODUCTION: Patients with PP or TP MS have been shown to have low brain T2 and T1 lesion loads and slow rates of new lesion formation with minimal gadolinium enhancement, despite their accumulating disability. Serial evaluation of these patients is needed to elucidate the pathological processes responsible for disease progression and to identify clinical and MRI measures which can monitor these processes in treatment trials. METHOD: Patients, recruited from six European centres, underwent two assessments on the expanded disability status scale (EDSS) and MRI of the brain and spinal cord, 1 year apart. RESULTS: Of the 167 patients studied (137 with PP MS and 30 with TP MS), 41 (25%; 35 PP and six TP) showed a one step increase in the EDSS. The mean number of new brain lesions seen was 0.88 in the PP group and 0.47 in the TP MS group. Both groups demonstrated change in T2 lesion load over the year (p< or =0.002), with median percentage changes of 7.3% in the PP group and 10. 8% in the TP MS group. The PP group also showed a significant change in T1 load (p< 0.001, median change 12.6%). The number of new cord lesions seen was small (mean of 0.14 in the PP group and no new cord lesions in the TP group). Both groups demonstrated a decrease in cord cross sectional area (p< 0.001, median changes; PP 3.8%, TP 4. 9%), but only the PP group showed evidence of significant brain atrophy (p<0.001, 0.95%). CONCLUSION: Although the monitoring of disease progression in this patient group is difficult, this study demonstrates changes in both lesion load and atrophy, which, if shown to correlate with clinical change over a longer time will facilitate therapeutic trial design.

Atrophy↗

PubMed2000

Use of a long-acting gonadotrophin-releasing hormone analogue in a postmenopausal woman with hyperandrogenism due to a hilus cell tumour.

OBJECTIVE: The aim of this study was to prove the utility of GnRH analogues for the suppression of androgen secretion in a postmenopausal woman with a suspected virilizing ovarian tumour. DESIGN AND METHODS: We present a case of a 72-year-old woman with virilization of recent onset. Hormonal studies revealed a fourfold increase in serum testosterone levels, normal dehydroepiandrosterone sulphate concentrations and high levels of serum 17-hydroxyprogesterone levels. Computed axial tomography scan of the ovaries was normal and the adrenal glands showed a discrete enlargement. The long-acting GnRH analogue, triptorelin, was injected initially (3.75mg i.m.) and serum hormone levels were measured weekly throughout one month. RESULTS: GnRH produced a decrease in serum testosterone levels to normal values, in parallel with the suppression of serum LH and FSH concentrations. The patient was treated for three months with triptorelin and she experienced an amelioration of the hyperandrogenic symptoms. In order to achieve a diagnosis, the patient was submitted to a laparotomy that revealed a small hilus cell tumour in the left ovary. CONCLUSION: GnRH analogues may offer a good therapeutic option in some states of gonadotrophin-dependent hyperandrogenism of ovarian origin.

Aged↗

PubMed2000

Stimulation of glucose transport by thyroid hormone in 3T3-L1 adipocytes: increased abundance of GLUT1 and GLUT4 glucose transporter proteins.

In 3T3-L1 adipocytes we have examined the effect of tri-iodothyronine (T(3)) on glucose transport, total protein content and subcellular distribution of GLUT1 and GLUT4 glucose transporters. Cells incubated in T(3)-depleted serum were used as controls. Cells treated with T(3) (50 nM) for three days had a 3.6-fold increase in glucose uptake (P<0.05), and also presented a higher insulin sensitivity, without changes in insulin binding. The two glucose carriers, GLUT1 and GLUT4, increased by 87% (P<0.05) and 90% (P<0. 05), respectively, in cells treated with T(3). Under non-insulin-stimulated conditions, plasma membrane fractions obtained from cells exposed to T(3) were enriched with both GLUT1 (3. 29+/-0.69 vs 1.20+/-0.29 arbitrary units (A.U.)/5 microg protein, P<0.05) and GLUT4 (3.50+/-1.16 vs 0.82+/-0.28 A.U./5 microg protein, P<0.03). The incubation of cells with insulin produced the translocation of both glucose transporters to plasma membranes, and again cells treated with T(3) presented a higher amount of GLUT1 and GLUT4 in the plasma membrane fractions (P<0.05 and P<0.03 respectively). These data indicate that T(3) has a direct stimulatory effect on glucose transport in 3T3-L1 adipocytes due to an increase in GLUT1 and GLUT4, and by favouring their partitioning to plasma membranes. The effect of T(3) on glucose uptake induced by insulin can also be explained by the high expression of both glucose transporters.

3T3 Cells↗

PubMed2000

Isolated demyelinating syndromes: comparison of different MR imaging criteria to predict conversion to clinically definite multiple sclerosis.

BACKGROUND AND PURPOSE: Various authors have developed criteria to classify MR imaging findings that suggest the possibility of multiple sclerosis. The purpose of this study was to evaluate and compare the capacity of three sets of MR imaging criteria for predicting the conversion of isolated demyelinating syndromes to clinically definite multiple sclerosis. METHODS: Seventy patients with clinically isolated neurologic symptoms suggestive of multiple sclerosis were prospectively studied with MR imaging. The MR imaging findings were evaluated by two independent neuroradiologists who were blinded to clinical follow-up data. Based on the clinical outcome at follow-up (presence of a second attack that established clinically definite multiple sclerosis), the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the criteria proposed by Paty et al, Fazekas et al, and Barkhof et al were calculated. RESULTS: Clinically definite multiple sclerosis developed in 22 (31%) patients after a mean follow-up time of 28.3 months. The criteria proposed by Paty et al and those proposed by Fazekas et al showed identical results: sensitivity, 86%; specificity, 54%; accuracy, 64%; positive predictive value, 46%; and negative predictive value, 89%. The criteria proposed by Barkhof et al showed the following: sensitivity, 73%; specificity, 73%; accuracy, 73%; positive predictive value, 55%; and negative predictive value, 85%. CONCLUSION: The four dichotomized MR imaging parameters proposed by Barkhof et al are more specific and accurate than the criteria proposed by Paty et al or Fazekas et al for predicting conversion to clinically definite multiple sclerosis.

Adult↗

PubMed2000

[Calcified cerebral metastases. Study of two cases and review of literature].

Although the most frequent cause of intracranial neoplasms are metastases, they very rarely calcify; classic histopathological series have shown the incidence to be approximately 1%. We have found 54 reported cases of intracranial calcified metastasis, the most frequent primary tumour reported being pulmonary adenocarcinoma (13 cases) and adenocarcinoma of gastrointestinal tract and adenocarcinoma of breast (8 cases each). Some reports have shown a longer survival in patients with this kind of image on cerebral scans. We present two patients with intracranial calcified metastasis due to dissemination in both cases of pulmonary adenocarcinomas. The survival under treatment in both patients was similar to that of patients with no calcified metastasis on brain scans. So, facing calcified intracranial lesions, metastatic origin should be considered in the differential diagnosis, pulmonary tumours being the first to be ruled out.

Adenocarcinoma↗

PubMed1999

[Optic neuritis, brain stem syndromes and myelitis: rapid conversion to multiple sclerosis].

BACKGROUND: To establish the early risk of multiple sclerosis (MS) following isolated demyelinating syndromes. PATIENTS AND METHOD: 36 patients with optic neuritis, 24 with brainstem syndromes, 27 with spinal cord syndromes and 8 patients with a poliregional syndrome were included in a prospective protocol: including clinical data, immunological determinations, oligoclonal bands, visual, somestesic and brainstem evoked potentials and a magnetic resonance imaging (MRI) study. RESULTS: MRI showed the presence of signal abnormalities in 70% of the patients. The conversion rate (CR) was 18.5%. In patients with a normal MRI, CR was 4% compared to 26% in patients with an abnormal MRI (p = 0.05). CONCLUSIONS: The early conversion rate to MS is significantly increased when MRI is abnormal.

Adolescent↗

PubMed1999

Primary and transitional progressive MS: a clinical and MRI cross-sectional study.

BACKGROUND: Ten percent of patients with MS have a progressive course from onset with no history of relapses or remissions. A smaller subgroup follow a similar progressive course but have a single relapse at some point (transitional progressive [TP] MS). To date these patients have been excluded from receiving licensed treatments for MS and from most therapeutic trials. OBJECTIVE: To document the clinical and MRI characteristics of a large cohort of progressive patients, including 158 with primary progressive (PP) MS and 33 with TPMS. Data from a small reference group of 20 patients with secondary progressive (SP) MS are also presented for reference. METHODS: Patients were recruited from six European centers. All underwent a clinical assessment including scoring on the Expanded Disability Status Scale (EDSS) and MRI of the brain and spinal cord. RESULTS: The men-to-women ratio was 81:77 (51% men) in the PP group, 14:19 (42% men) in the TP group, and 5:15 (25% men) in the SP group. The mean age at disease onset was significantly higher in the PP group than it was in the other two groups (PP 40.2 years, TP 34.9 years, SP 28.7 years). On MRI the PP group had lower mean brain T2 and T1 hypointensity lesion loads than the SP group (T2 12.02 versus 27.74 cm3, p = 0.001; T1 4.34 versus 7.04 cm3, p = 0.015). The SP and TP cohorts had significantly more T2-weighted lesions in the spinal cord than the PP patients, and the SP cohort had the greatest degree of atrophy. There was a correlation in the PP and TP patients between EDSS score and brain and spinal cord atrophy (r = 0.3, 0.2, p < or = 0.006) but not with brain lesion load. The PP and TP patients who presented with spinal cord pathology had significantly lower brain T2 and T1 lesion loads than those with non-spinal cord presentations (p = 0.002). CONCLUSIONS: The monitoring of disease progression in PPMS is difficult, although measures of atrophy correlate with the EDSS and appear most promising. This study increases our understanding of this unique patient group, which will be further expanded with the acquisition of serial data.

Adult↗

PubMed1999

Macrocephaly and dilated Virchow-Robin spaces in childhood.

We report two children who presented with progressive macrocephaly and dilated Virchow-Robin spaces on magnetic resonance imaging. Follow-ups of 1-4 years and 5-9 years, respectively, showed normal neuro-developmental progress. We suggest that dilated Virchow-Robin spaces in patients with macrocephaly is a benign association.

Abnormalities, Multiple↗

PubMed1999

Induction of microalbuminuria by l-arginine infusion in healthy individuals: an insight into the mechanisms of proteinuria.

Despite evidence from individuals with diabetes mellitus or reduced renal mass, the actual relationship between protein- or amino acid-induced changes in renal function and urinary albumin excretion (UAE) is largely unknown in subjects without renal disease. In humans, infusions of l-arginine have been used recently in vascular and renal pathophysiological studies. The present study was undertaken to analyze the mechanisms involved in a particular effect; namely, the behavior of UAE during amino acid loading. A prospective interventional protocol was performed on 10 healthy adults by means of an intravenous infusion of l-arginine. The main results show that l-arginine induced a significant increase in UAE from 13.1 +/- 3.8 before to 53.3 +/- 11.1 microgram/min after the infusion (P < 0.005). This increment was simultaneous to an increase in glomerular filtration rate (GFR) and renal plasma flow (RPF). Furthermore, l-arginine markedly increased the urinary excretion of beta2-microglobulin. UAE correlated significantly with GFR (r = 0. 738; P = 0.014) and RPF (r = 0.942; P < 0.0001), but not with urinary beta2-microglobulin (r = 0.05; P = not significant). Furthermore, marked differences (P = 0.001) were found between the percentage of increase in UAE (306.8% +/- 163.2%) with respect to either albumin filtered load (FLAlb; 57.9% +/- 16.3%) and beta2-microglobulin excretion (1,088.5% +/- 424.6%). No changes were found in vehicle-infused individuals. In conclusion, the present study shows, in controlled conditions, that l-arginine infusion induces a relevant increase in UAE in healthy individuals that significantly exceeds that expected from the increase in GFR alone. The intense and simultaneous increment in beta2-microglobulin excretion strongly suggests that the effect of l-arginine on UAE is, in a relevant part, mediated through a blockade in the tubular protein reabsorption pathways. However, the profound differences observed in the changes induced by l-arginine on UAE and beta2-microglobulin excretion and the differences in the correlation of UAE and beta2-microglobulin with respect to GFR suggest that substantial diversity exists in the mechanisms by which l-arginine affects the renal management of albumin and beta2-microglobulin. These findings are relevant for understanding the renal response to l-arginine and protein/amino acid loads.

Adult↗

PubMed1999

Hyperkalemia in patients infected with the human immunodeficiency virus: involvement of a systemic mechanism.

BACKGROUND: The appearance of hyperkalemia has been described in human immunodeficiency virus (HIV)-positive patients treated with drugs with amiloride-like properties. Recent in vitro data suggest that individuals infected with HIV have alterations in transcellular K+ transport. METHODS: With the objective of examining the presence of alterations in transmembrane K+ equilibrium in HIV-positive patients, we designed a prospective, interventional study involving 10 HIV-positive individuals and 10 healthy controls, all with normal renal function. An infusion of L-arginine (6%, intravenously, in four 30-min periods at 50, 100, 200, and 300 ml/hr) was administered, and plasma and urine electrolytes, creatinine, pH and osmolality, total and fractional sodium and potassium excretion, transtubular potassium gradient, plasma insulin, renin, aldosterone, and cortisol were measured. RESULTS: A primary disturbance consisting of a significant rise in plasma [K+] induced by L-arginine was detected in only the HIV patients but not in the controls (P < 0.001 between groups). A K+ redistribution origin of the hyperkalemia was supported by its rapid development (within 60 min) and the lack of significant differences between HIV-positive individuals and controls in the amount of K+ excreted in the urine. The fact that the HIV-positive individuals had an inhibited aldosterone response to the increase in plasma K+ suggested a putative mechanism for the deranged K+ response. CONCLUSIONS: These results reveal that HIV-infected individuals have a significant abnormality in systemic K+ equilibrium. This abnormality, which leads to the development of hyperkalemia after the L-arginine challenge, may be related, in part, to a failure in the aldosterone response to hyperkalemia. These results provide a new basis for understanding the pathogenesis of hyperkalemia in HIV individuals, and demonstrate that the risk of HIV-associated hyperkalemia exists even in the absence of amiloride-mimicking drugs or overt hyporeninemic hypoaldosteronism.

Adult↗

PubMed1999

Comparison of high and low doses of trimethoprim-sulfamethoxazole for primary prevention of toxoplasmic encephalitis in human immunodeficiency virus-infected patients.

To evaluate the influence of the dose of co-trimoxazole prophylaxis on the risk of toxoplasmosis in human immunodeficiency virus (HIV)-infected patients, we performed a nested case-control study of 32 patients with toxoplasmosis (case patients) and 64 patients without toxoplasmosis (control patients) who were matched by CD4 cell count and Toxoplasma gondii serostatus; these patients were from a cohort of 521 HIV-infected patients who underwent a diagnostic neuroimaging study between March 1993 and January 1997. Twenty-seven (84.4%) of 32 case patients and 33 (51.6%) of 64 control patients received low doses of co-trimoxazole, a finding associated with an adjusted odds ratio (OR) of 9.36 (95% confidence interval [CI], 2.05-42.75) and indicating 89% protective efficacy for high doses. Fifteen (46.9%) of 32 case patients and 16 (25%) of 64 control patients were exposed to rifampin (adjusted OR, 3.38; 95% CI, 1.08-10.61). These results indicate that high doses of co-trimoxazole appear to be more effective than low doses for lowering the risk of toxoplasmosis in HIV-infected patients and that rifampin therapy may reduce the efficacy of co-trimoxazole.

AIDS-Related Opportunistic Infections↗

PubMed1999

Impaired cerebrovascular reactivity as a risk marker for first-ever lacunar infarction: A case-control study.

BACKGROUND AND PURPOSE: Functional assessment of small arteries and arterioles could provide valuable information regarding the extent of diffuse arteriolosclerosis in patients with small-vessel disease. Therefore we attempted to clarify the role of cerebrovascular reactivity (CVR) as a risk marker for first-ever symptomatic lacunar infarction. METHODS: Forty-six patients with lacunar infarction and 46 sex- and age-matched control subjects were prospectively evaluated. Cerebral hemodynamics were studied with transcranial Doppler ultrasonography. CVR was examined by calculating the percent increase in mean flow velocity occurring after 15 mg/kg acetazolamide administration (Diamox test). RESULTS: CVR was significantly (P<0.0001, Student's t test) lower in cases (50.0+/-12. 7%) as compared with control subjects (65.2+/-12.4%). A multiple logistic regression analysis identified male sex (odds ratio [OR] 2. 3, P=0.02), age (OR 3.6, P<0.005), and the presence of lacunar infarction on magnetic resonance imaging (OR 5.3, P<0.001) as significant and independent factors associated with a reduction of CVR. Moreover, a cut-point of 55.6% (sensitivity 67%, specificity 82%) was established as the threshold value for distinguishing between pathological and normal CVR. CVR was significantly (P=0.02) lower in patients with multiple (46.38+/-12.6%) than with single (54. 83+/-11.58%) lacunar infarction. In addition, a trend of negative correlation was found between CVR and the number of lacunar infarctions (r=-0.26, P=0.08). In the multiple logistic model, history of hypertension (OR 7.24; 95% confidence interval 2.95 to 17. 79) and CVR (OR 0.8; 95% confidence interval 0.81 to 0.93) emerge as significant and independent predictors of first-ever lacunar infarction. CONCLUSIONS: These data suggest that impaired CVR is a risk marker for first-ever lacunar infarction.

Acetazolamide↗

PubMed1999

Spontaneous ventriculostomy: report of three cases revealed by flow-sensitive phase-contrast cine MR imaging.

Spontaneous ventriculostomy is a rare condition that occurs with the spontaneous rupture of a ventricle, resulting in a communication between the ventricular system and the subarachnoid space. Three cases of spontaneous ventriculostomy through the floor of the third ventricle that occurred in cases of chronic obstructive hydrocephalus are presented. The communication was identified via flow-sensitive phase-contrast cine MR imaging. Spontaneous ventriculostomy is probably a result of a rupture of the normally thin membrane that forms the floor of the third ventricle and, with long-standing obstructive hydrocephalus, creates an internal drainage pathway that spontaneously compensates for the hydrocephalus.

Adolescent↗

PubMed1999

Radiologic findings in two cases of acute Schmörl's nodes.

We describe two cases of atypical acute Schmörl's nodes, one benign, the other on a tumoral vertebra. In both cases, MR imaging showed a decreased vertebral T1 signal and a slightly increased T2 signal. These signal intensities are indistinguishable from tumoral disease or inflammatory lesions. The identification of endplate defects or intranuclear cleft bending of the disk by either CT or MR may be helpful for the correct diagnosis of acute Schmörl's nodes.

Adult↗

PubMed1999

Lumbar extradural hemangiomas: report of three cases.

The CT, MR, and histologic findings of three patients with surgically proved lumbar extradural cavernous and arteriovenous hemangiomas are reported. All three patients suffered from radicular and low back pain that disappeared completely or nearly so after total surgical excision. In each case, neuroimaging studies showed a well-defined ventrally located extradural mass with no bone involvement. On MR images, all lesions were homogeneous and isointense on noncontrast T1-weighted images and hyperintense on T2-weighted images relative to the intervertebral disk. Homogeneous enhancement was seen in one of the two cases in which contrast-enhanced T1-weighted images were obtained. Purely extradural hemangiomas should be included in the differential diagnosis of lumbar extradural soft-tissue lesions. Features that may help to distinguish this entity from the more common extruded disk herniation or neurogenic tumors are its homogeneous high signal intensity on T2-weighted images, ovoid shape, and lack of anatomic relationship with the adjacent intervertebral disk or exiting nerve root.

Adolescent↗

PubMed1998

31Phosphorus magnetic resonance spectroscopy in the assessment of head and neck tumors.

PURPOSE: 31Phosphorus magnetic resonance spectroscopy (31P-MRS) provides biochemical information in a noninvasive way. The aim of this work was: (a) to characterize the 31P spectrum of advanced head and neck tumors, and (b) to evaluate the spectral changes after treatment and to correlate them with the pathologic response. METHODS AND MATERIALS: A total of 20 patients diagnosed with advanced head and neck tumors and 7 healthy controls participated in the study. The tumor mass and its contralateral side were studied by means of 31P-MRS before and after treatment. Neck muscles of a control group were also studied. RESULTS: Tumors presented ratios of phosphomonoesters (PME), phosphodiesters (PDE), and inorganic phosphate (Pi) with respect to the adenosine triphosphate (ATP), significantly higher and a PCr (phosphocreatine)/ATP ratio lower than the neck muscle of volunteers or the contralateral side. The PDE/ATP and PME/ATP ratio values obtained before therapy were similar, independent of the later response to treatment. However, when there was a complete response, the ratios measured after treatment were decreased. CONCLUSION: These results show the existence of significant differences between the 31phosphorus spectrum of tumors and neck muscle, but also between the tumors and their contralateral sides. Moreover, 31P-MRS is able to detect metabolic changes after a complete response. These results suggest that 31P-MRS would be useful in the evaluation of the clinical response of head and neck tumors.

Adenosine Triphosphate↗

PubMed1998

High glucose uptake by adipocytes in a type 1 diabetic patient with a partial 'honeymoon' period.

Hypoglycaemic episodes and low insulin requirements are frequently seen in the early phase of treatment of Type 1 diabetes mellitus but the mechanism is not clear. We present a diabetic patient with recurrent hypoglycaemia in the early phase of insulin treatment. A very high glucose transport in adipocytes (basal: 176 and insulin stimulated glucose transport 10(-7) mol l(-1): 335 fl cell(-1) s(-1)) was found when compared with reference laboratory diabetic patients (basal: 59 +/- 10 and insulin 10(-7) mol l(-1): 106 +/- 7 fl cell(-1) s(-1), mean +/- SE) and with reference laboratory of non-diabetic subjects (basal: 106 +/- 6 and insulin 10(-7) mol l(-1): 188 +/- 15 fl cell(-1) s(-1)). Insulin binding to adipocytes was in the normal range. The patient was studied again 1 year later when the partial clinical remission had disappeared, and the glucose transport in adipocytes had decreased. In conclusion, an increase in glucose uptake by peripheral tissues may be among the mechanisms of the partial 'honeymoon' period of diabetic patients.

Adipocytes↗

PubMed1998

Response to acyclovir in two cases of herpes zoster leukoencephalitis and review of the literature.

Herpes zoster leukoencephalitis is a rare complication of varicella-zoster virus infection. Associated with high mortality, the majority of cases have been discovered postmortem; today, however, magnetic resonance imaging is being used successfully as an aid in the diagnosis of this disease. The first two reported cases of HIV-infected patients with herpes zoster leukoencephalitis who recovered clinically and showed complete resolution of the magnetic resonance demyelination images after acyclovir treatment are described. In addition, the cases of herpes zoster leukoencephalitis reported in the literature to date are reviewed.

AIDS-Related Opportunistic Infections↗