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Biomedical subjects

S Iglesias

Publications and source records attributed to S Iglesias.

At least 19 recordsLinked to original sources

Hemorrhagic stroke associated with the Iowa amyloid precursor protein mutation.

The authors searched for mutations in the beta-amyloid precursor protein in a Spanish family with a hereditary syndrome of hemorrhagic stroke, dementia, leukoencephalopathy, and occipital calcifications. DNA from two affected members demonstrated the Iowa amyloid precursor protein mutation previously identified as a cause of severe amyloid angiopathy without hemorrhagic stroke. These data point to other genetic or environmental factors that may determine the occurrence of symptomatic hemorrhage in amyloid angiopathy.

Age of Onset↗

Appendectomies in rural hospitals. Safe whether performed by specialist or GP surgeons.

OBJECTIVE: To compare outcomes of appendectomies performed in rural hospitals by specialist surgeons and GP surgeons. DESIGN: Retrospective analysis of the Canadian Institute for Health Information's (CIHI) Discharge Abstract Database (DAD) 1996-1999. SETTING: Rural hospitals in Ontario, Saskatchewan, Alberta, and British Columbia. PARTICIPANTS: All surgeons who performed appendectomies in these hospitals during the study period. MAIN OUTCOME MEASURES: Mortality; diagnostic accuracy, perforation, and repeat laparotomy rates; length of stay; and need for transfer to another acute-care institution. RESULTS: Specialist surgeons performed 3624 appendectomies; GP surgeons performed 963. Rates of comorbidity, diagnostic accuracy, and transfer, and mean lengths of stay were similar for patients of GP and specialist surgeons. Patients operated on by specialists were older and more likely to have perforations and to require second intra-abdominal or pelvic procedures. Triage to a specialist, older age, and comorbidity all independently predicted perforation. Only perforation predicted a second intra-abdominal or pelvic procedure. CONCLUSION: Appendectomy is a safe procedure in rural hospitals, whether performed by specialist or GP surgeons. Some difficult cases are routinely referred to specialists.

Adolescent↗

Familial occipital calcifications, hemorrhagic strokes, leukoencephalopathy, dementia, and external carotid dysplasia.

OBJECTIVE: To describe a new familial association of late-onset dementia, patchy leukoencephalopathy, intracerebral hemorrhages, bilateral occipital calcifications (BOC), and external carotid artery dysplasia (ECAD). METHODS: At age 62, the proband, who was of Spanish descent, had left temporal hemorrhage in a background of progressive mental deterioration. Neuroimaging revealed fine tram-line BOC, extensive leukoencephalopathy, and bilateral ECAD. Biologic screening for celiac disease was negative. Skin biopsy with ultrastructural study revealed heretofore unreported changes in the basal lamina of capillaries, with multilayered appearance and round-shaped microcalcifications. Of 19 next-of-kin who survived beyond 60 years of age, six had brain disorders; four of the six presented at least three components of the syndrome. The proband's mother had died at age 83 with profound dementia; one sister, who was diagnosed with dementia with BOC and leukoencephalopathy at age 67, died 2 years later from intracerebral hemorrhage; a brother had an occipital hemorrhage at age 58, at which time BOC and leukoencephalopathy were discovered; and another brother died after a minor stroke at age 70 with dementia, leukoaraiosis, BOC, and ECAD. A proband's cousin also had an unexplained ischemic stroke at age 55, but without other features of the entity. In no subject was there evidence of seizures, facial angioma, or intracranial vascular malformation, and arterial hypertension was neither constant nor severe. CONCLUSION: These clinical, neuroradiologic, and histologic features suggest a new familial cerebrovascular entity with widespread microvascular calcifications and autosomal (presumably dominant) inheritance. We suggest the acronym FOCHS-LADD, for familial occipital calcifications, hemorrhagic strokes, leukoencephalopathy, arterial dysplasia, and dementia.

Aged↗

Voxel-based mapping of irreversible ischaemic damage with PET in acute stroke.

Objective mapping of irreversible tissue damage in the acute stage of ischaemic stroke would be useful for prognosis and in assessing the efficacy of therapeutic manoeuvres in impeding extension of infarction. From our database of 30 patients studied with 15O-PET within 5-18 h after onset of first-ever middle cerebral artery territory stroke, we extracted a subgroup of 19 survivors (age 74.6 +/- 8.5 years) in whom late CT coregistered with PET was available to determine final infarct topography. By means of a voxel-based analysis of the PET data, we determined putative thresholds for irreversible tissue damage as the lower limit of the 95% confidence interval calculated from all voxels within the ultimately non-infarcted brain parenchyma ipsilateral to the insult. The following values were found: 8.43 ml/100 ml/min, 0.87 ml/100 ml/min, 1.64 ml/100 ml, 0.27 and 2.21/min, for cerebral blood flow (CBF), oxygen consumption (CMRO2), blood volume (CBV), oxygen extraction fraction and the ratio CBF : CBV, respectively. Voxels below these thresholds occurred significantly more frequently in the final infarct region than in the non-infarcted parenchyma for CBF and CMRO2 (P = 0.016 and P = 0.0045, respectively, Wilcoxon test), but not for the other PET variables. Furthermore, with both CBF and CMRO2, the percentage of irreversible tissue damage voxels in the affected hemisphere relative to the opposite hemisphere was significantly positively correlated to both the volume of final infarct and the neurological outcome at 2 months (all P < 0.005, Spearman ranked test). These findings validate our voxel-based CBF and CMRO2 thresholds for probabilistic mapping of irreversible tissue damage within the 5-18 h interval after stroke onset; however, whether they would be applicable to earlier intervals remains to be determined. Transfer of our procedure for determination of irreversible tissue damage thresholds to other imaging modalities such as single proton emission computed tomography and diffusion-weighted MRI should be straightforward.

Aged↗

Episodic memory in transient global amnesia: encoding, storage, or retrieval deficit?

OBJECTIVES: To assess episodic memory (especially anterograde amnesia) during the acute phase of transient global amnesia to differentiate an encoding, a storage, or a retrieval deficit. METHODS: In three patients, whose amnestic episode fulfilled all current criteria for transient global amnesia, a neuropsychological protocol was administered which included a word learning task derived from the Grober and Buschke's procedure. RESULTS: In one patient, the results suggested an encoding deficit, and in two others, a storage deficit. CONCLUSIONS: The encoding/storage impairment concerning anterograde amnesia documented in our patients stands in clear contrast with the impairment in retrieval which must underly the retrograde amnesia that also characterises transient global amnesia. This dissociation in turn favours the idea of a functional independence among the cognitive mechanisms that subserve episodic memory.

Aged↗

Oxidative stress in chronic renal failure.

This study focuses on the oxidative stress in patients with severe chronic renal failure who are not undergoing dialysis treatment. The erythocyte levels, creatinine clearing and plasma- and cell activities of the following enzymes were determined: glutathione peroxidase (Gpx), superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione transferase (GT). The concentrations of non-enzyme molecules such as total glutathione in both oxidized and reduced forms, and malonyldialdehyde (MDA) were also measured. The obtained values were compared with those in healthy blood donors of comparable age and social status. The results indicate that chronic renal patients have lower glutathione levels and reduced activities of glutathione peroxidase and of glutathione reductase, while exhibiting elevated levels of malonyldialdehyde and activities of superoxide dismutase, glutathione transferase, and catalase. Finally, creatinine clearing was found to be correlated (p < 0.001) to total (oxidized and reduced) glutathione, Gpx and MDA. These observations may serve to establish a simple protocol for evaluation of renal function.

Biomarkers↗

Paraneoplastic cerebellar syndrome and optic neuritis with anti-CV2 antibodies: clinical response to excision of the primary tumor.

OBJECTIVE: To describe a patient with a paraneoplastic cerebellar syndrome and optic neuritis with circulating anti-CV2 antibodies and clinical improvement after excision of a small cell lung carcinoma. DESIGN: Report of a case. SETTING: A 62-year-old man simultaneously developed a severe cerebellar syndrome and a bilateral optic neuritis predominantly in the left eye (visual acuity, 20/25 in the right eye; < 20/400 in the left eye; and bilateral swelling of the optic discs). MAIN OUTCOME AND RESULTS: Anti-CV2 antibodies, recently described as associated with paraneoplastic neurological syndrome, were detected in the patient's serum sample. These antibodies were demonstrated to react with the cytoplasm of a subpopulation of oligodendrocytes in the white matter of rat brain in the cerebellum, brainstem, spinal cord, and optic chiasm. The patient was found to have a small cell lung carcinoma, which was removed. After excision of the tumor, the cerebellar syndrome improved dramatically and the papilledema disappeared despite aftereffects of the optic neuritis. CONCLUSIONS: These findings were consistent with the diagnosis of a paraneoplastic neurological syndrome, although both optic neuritis and remission of the cerebellar syndrome are uncommon patterns of paraneoplastic syndromes. CV2 antigen expression by the oligodendrocytes of the cerebellum, brainstem, spinal cord, and optic chiasm correlated with the clinical syndrome observed in our patient. However, the precise pathophysiological role of anti-CV2 antibodies is still unknown.

Autoantibodies↗

Do changes in oxygen metabolism in the unaffected cerebral hemisphere underlie early neurological recovery after stroke? A positron emission tomography study.

BACKGROUND AND PURPOSE: Whether an initial depression of function in the unaffected hemisphere ("transcallosal diaschisis") plays a role in early neurological recovery after acute stroke remains controversial. Previous studies were confounded by lack of acute-stage assessment with follow-up and by the problem of defining a suitable control group, since preexisting stroke risk factors may influence prestroke cerebral metabolism. We evaluated with positron emission tomography (PET) the relationships between unaffected-hemisphere (ie, contralateral) oxygen consumption (cCMRO2) and quantitative neurological assessments (and their respective evolution over time) after ischemic stroke. METHODS: Among 30 consecutive patients with first-ever middle cerebral artery ischemic stroke studied with the (15)O equilibrium method, we selected all survivors (n=19; mean age, 74.6 years) who were investigated both within the first 18 hours after stroke onset (PET1; mean, 11 +/- 4 hours) and 15 to 30 days later (PET2; mean, 24 +/- 10 days), with each patient serving as his/her own control. Neurological deficits were quantified using Orgogozo's middle cerebral artery scale (N score) at each PET session. Neurological changes were calculated as changes in the N score. A late CT scan coregistered with PET provided infarct topography and volume index. RESULTS: At PET2, we observed the overall expected neurological recovery. There was a nearly significant trend for a decrease in cCMRO2 from PET1 to PET2, especially for the neocortex (P=.08, F test); in a subgroup of eight patients with large infarcts, this CMRO2 decline was significant (P<.05) in the mirror region to the infarct. There was no significant correlation (Spearman's tests) between acute-stage cCMRO2 and same-day N scores or between changes in cCMRO2 versus changes in N score from PET1 to PET2 (any region). There was a nearly significant trend for lower PET2 cCMRO2 in the subgroup of eight patients with large compared with small infarcts (P=.06). CONCLUSIONS: We found no evidence for an influence of cCMRO2 on acute-stage neurological deficit or for a role of the unaffected hemisphere in early recovery after acute MCA ischemic stroke. The decline in unaffected-hemisphere metabolism from the acute to the subacute stage in the face of overall clinical recovery appears clinically irrelevant. The fact that the neocortical cCMRO2 at PET2 tended to be lower, and declined significantly from PET1 to PET2 in the mirror region in the subgroup of patients with large infarcts, suggests that this delayed effect represents transcallosal fiber degeneration.

Aged↗

Precancerous pathology evoked by hexachlorobenzene treatment.

The porphyrinogenic and carcinogenic ability of hexachlorobenzene (HCB) was assayed in male and female gold hamsters, and histological examinations of tissue alterations were performed. So it was studied, in liver: a) porphyrin content which was significantly increased at five months of HCB treatment, specially in males, and the pattern of accumulated porphyrins which was altered independent of the sex, b) haem pathway enzymes:delta aminolaevulinic acid synthase, ferrochelatase and porphyrinogen carboxylyase (PCL); among which only PCL appeared to be altered just at ten months of HCB feeding. While thyroid gland and kidney remained unaltered along the treatment time, liver and spleen exhibited a noticeable size variation and morphological alterations. In fact the spleen in treated animals was hypotrophic showing a red pulp less developed with respect to the Malpighian corpuscles and many macrophages with iron deposits. Respect to the liver, enlargement in size of hepatocytes, high content of iron deposits, no PAS positive structures in the cytoplasm, several small lipid droplets, microsteatosis although no cytonecrosis, polymorphic nuclei, and proliferations of nucleoli were observed. Therefore HCB is able to cause precancerous pathology and to induce porphyria in hamsters, but not hyperthyroidism, upon this experimental conditions. By the way, males were found to be a good experimental model, better than females, to study the earliest relations between porphyria and cancer.

Animals↗

Porphyrinogen carboxylyase. Studies on the existence of isoenzymes.

Porphyrinogen carboxylyase from normal rat liver was subjected to purification methods. Two different purification protocols were used. In both cases, the initial steps consisted in obtaining a liver homogenate, followed by centrifugation, salt precipitation and phosphate gel absorption. Scheme I consisted in then submitted the preparation to DEAE-cellulose, followed by Sephacryl S-200 and Phenyl-sepharose sequential column chromatographies. Scheme II involved an affinity column followed by a Sephadex G-75 gel filtration column. In both cases, the enzyme was stored at -20 degrees C until its assay. The addition of 2mM dithiotreytol to the incubation media or to the enzyme extract before storage, did not help improve the activity nor the stability of the enzyme. Those fractions containing the maximal enzyme activity, detected using Uroporphyrinogen III or Pentacarboxy-porphyrinogen III as substrate, were not always present in the same tubes for the different columns employed. In addition, the degree of purification obtained in some steps was different according to the substrate employed. The results suggest the existence of at least two isoenzymes for rat liver porphyrinogen carboxy-lyase.

Animals↗

[Unusual triggering circumstance of benign acute cerebral angiopathy; link with exertion cephalalgia?].

Immediately following a scream of fear, a sixty-year old woman complained of severe bilateral headache which relapsed several times over the following month during exercise. There was no history of sympathomimetic drug intake. The work-up was normal save for minimal subarachnoid bleeding and the angiogram showed a disseminated "sausage-string" appearance over all cerebral arterial territories, without aneurysm. The unusual triggering event in this case and the subsequent recurrence of headache in relation to exercise lead us to discuss possible links between the clinical entity of "Isolated benign cerebral angiopathy" and exertional headache.

Cerebral Arteries↗

Migraine and risk of ischaemic stroke: a case-control study.

OBJECTIVES: To determine whether migraine is a risk factor for ischaemic stroke. DESIGN: A case-control study. SETTING: Two hospitals in Paris. SUBJECTS: 212 patients with stroke (137 men and 75 women) and 212 controls matched for sex, age (to within five years), and history of hypertension. MAIN OUTCOME MEASURES: Ischaemic stroke, confirmed by brain computed tomography or magnetic resonance imaging, and history of headache, recorded with structured questionnaire during interview. RESULTS: Prevalence of migraine did not differ between patients with stroke and controls: 18/137 v 17/137 for men (odds ratio 1.1 (95% confidence interval 0.5 to 2.2), p = 0.86); 23/75 v 17/75 for women (odds ratio 1.6 (0.7 to 3.5), p = 0.24); and 41/212 v 34/212 for both sexes (odds ratio 1.3 (0.8 to 2.3), p = 0.33). When subjects were split into two age groups, however, prevalence of migraine was significantly higher among younger women (aged < 45) with stroke compared with their controls (13/20 v 6/20, odds ratio 4.3 (1.2 to 16.3), p = 0.03). Furthermore, the risk of ischaemic stroke was higher among younger women who smoked (7/20 v 1/20, odds ratio 10.2 (1.1 to 93.3)). CONCLUSIONS: Prevalence of migraine was not different between patients with stroke and matched controls except among women aged < 45, when migraine and stroke were significantly associated.

Adolescent↗

Reducing the cesarean section rate in a rural community hospital.

OBJECTIVE: To determine the success of a program designed to reduce the cesarean section rate in a rural community hospital, to identify reasons for any reduction in the rate and to identify any accompanying increases in the maternal and neonatal morbidity and mortality rates. DESIGN: Longitudinal study of modes of delivery. SETTING: A 44-bed community hospital with a medical staff of nine family physicians serving a population of 9000. PATIENTS: All 1161 women who gave birth at the hospital from Jan. 1, 1985, to Dec. 31, 1989. Routinely recorded data were manually extracted from medical charts and entered into a computer database. INTERVENTION: The guidelines of the National Consensus Conference on Aspects of Cesarean Birth (NCCACB) for vaginal birth after cesarean section (VBAC), management of breech presentation and the diagnosis of dystocia requiring cesarean section were introduced at the hospital in 1985. OUTCOME MEASURES: The annual overall cesarean section rates and the rates among nulliparous women, multiparous women eligible for VBAC and multiparous women ineligible for VBAC. RESULTS: The overall cesarean section rate decreased from 23% in 1985 to 13% in 1989 (p = 0.001). Among the nulliparous women the rate decreased from 23% to 12%, but the difference was insignificant (p = 0.069); this decrease was due to a drop in the number of dystocia-related cesarean sections. The rate among VBAC-eligible multiparous women decreased from 93% to 36% (p less than 0.001) because of an increased acceptance of VBAC by the patients and the physicians. The rate among multiparous women ineligible for VBAC was virtually unchanged. There were 20 neonatal transfers to an intensive care unit, with no tendency toward an increase over the study period. None of the mothers died; one newborn, of a nulliparous woman, died from a prolapsed umbilical cord. CONCLUSIONS: The program was accompanied by a significant decrease in the cesarean section rate. Rural hospitals with facilities and personnel for emergency cesarean sections should consider the introduction of a similar program.

Alberta↗

Effects of Escherichia coli lipopolysaccharide on the phosphoinositide metabolism and serotonin secretion in thrombin-activated platelets.

Lipopolysaccharide treatment of platelets in basal conditions does not produce any effect on serotonin secretion or on phosphatidic acid synthesis or arachidonic acid release. However, a brief exposure of platelets to endotoxin enhances the thrombin-stimulated activation of these parameters, whereas a more prolonged treatment with lipopolysaccharide impairs thrombin action. The results presented here also suggest that very short-term treatment of platelets with lipopolysaccharide activates the inositol 1,4,5-trisphosphate 3-kinase. The long-term effects of endotoxin could be mediated by protein kinase C activation.

Animals↗

Arachidonic acid releasing systems in pig aorta endothelial cells.

Endothelial cells synthesize prostacyclin both from platelet-derived endoperoxides and from the arachidonic acid released from its intracellular stores. The mechanisms controlling this release does not appear to be mediated through phospholipid methylation but by means of phosphoinositide hydrolysis. As yet two possible mechanisms have so far been proposed to regulate arachidonic acid release in a number of cellular systems: phospholipase C-controlled phospholipase A2 activity or phospholipase C-diglyceride lipase system. The results presented here show that using phospholipases inhibitors is not a reliable strategy to study arachidonic acid release in cultures of endothelial cells. Our data also strongly suggest that the release of prostacyclin may be accounted in these cells for by a phospholipase C-diglyceride lipase system.

Animals↗

Ionophore A23187 induces a refractory state in thrombin-activated release of inositol phosphates.

The phosphatidylinositol cycle has been proposed to be involved in the regulation of platelet functionality through the control of cytoplasmic Ca2+ levels. However, the requirements of phospholipase C for Ca2+ has not yet been elucidated in intact platelets. The primary purpose of the present study was to investigate the Ca2+ requirements of this enzyme in platelets from miniature swine by taking advantage of the permeabilizing properties of the ionophore A23187. Our results strongly suggest that the treatment of platelets with A23187 induces a refractory state in thrombin-stimulated release of inositol phosphates while 5-hydroxytryptamine (serotonin)-secretory capacity in response to thrombin remained constant. This refractory state seems to be dependent on some cytochalasin-inhibitable cytoskeletal phenomena.

Animals↗

Predictive value of (99m)Tc-HMPAO-SPECT for neurological Outcome/Recovery at the acute stage of stroke.

BACKGROUND AND PURPOSE: Combined perfusion and oxygen metabolism PET imaging is highly predictive of spontaneous outcome after middle cerebral artery (MCA) stroke, independent of clinical scores, but whether the assessment of perfusion alone by SPECT provides similar information remains unclear. We have assessed the prognostic value of (99m)Tc-HMPAO-SPECT at the acute stage of stroke. METHODS: Twenty-seven first-ever nonhemorrhagic MCA territory stroke patients were prospectively studied 4-20 h (mean: 12 h) after onset with (99m)Tc-HMPAO-SPECT. None was part of a therapeutic trial or received thrombolysis. Neurological deficits were quantified at admission and 2 months later with Orgogozo's MCA scale. SPECT images were visually classified by 3 independent observers into one of three patterns, as follows: pattern I = marked and extensive tracer hypofixation; pattern II = moderate and/or focal hypofixation with or without combined hyperfixation, and pattern III = normal or increased uptake without hypofixation. In addition to this visual analysis, we also calculated a voxel-based 'hypoperfusion score', an index of severity x extent of hypofixation according to Mountz's method. RESULTS: There was a good intra- and interobserver agreement. After consensus, 9, 14 and 4 patients were classified in patterns I, II and III, respectively. These patterns had a significant predictive value for raw outcome but not for percentage recovery (p = 0.008 and p = 0.127, respectively). Thus, all patients in pattern III had a good outcome, while most (but not all) patients in pattern I had a poor or intermediate outcome; pattern II patients were more evenly distributed among outcomes. Hypoperfusion scores were highly significantly positively correlated with both 2-month outcomes and percentage recoveries, even after controlling the predictive value of day 0 MCA scores by partial correlations. COMMENTS: We found that SPECT had a significant added predictive value even when compared to admission neurological scores. Although less accurate than PET, (99m)Tc-HMPAO-SPECT may help to predict spontaneous individual neurological evolution, especially whenever perfusion images are normal or show an increased tracer uptake without associated hypofixation.

Acute Disease↗