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Biomedical subjects

C A Buchpiguel

Publications and source records attributed to C A Buchpiguel.

At least 19 recordsLinked to original sources
PubMed2003

Primary chemotherapy effect in sentinel node detection in breast cancer.

PURPOSE: Sentinel node (SN) biopsy is a reliable method for improved staging of breast cancer, offering an alternative to routine axillary dissection. Perhaps preoperative chemotherapy could increase the rate of false-negative SN because of induced lymphatic changes. The aim of the study was to evaluate the utility of lymphoscintigraphy and of hand-held probe detection in the SN approach after chemotherapy, correlating it with histologic analysis of the axilla. METHODS: Eighty-three patients (mean age, 53 years; TNM stage I) were studied prospectively. They were separated into two groups: group 1 (G1), 37 patients with preoperative chemotherapy and group 2 (G2), 46 patients without chemotherapy. Mean tumor size was 2 cm in both groups. Lymphoscintigraphy was performed 3 to 4 hours after peritumoral injection of Tc-99m dextran-70 in a 0.2-ml volume and activity of 14.8 MBq (0.4 mCi), performed under ultrasound or mammographic control. On the following day, each patient underwent tumor resection with axillary dissection, included the SN. RESULTS: The SN was detected by scintigraphy in 78 patients (94%). The failure of SN to predict the axillary histologic status was significantly higher (P = 0.01) in G1 than in G2 (7 and 1 false-negative result, respectively). CONCLUSION: Preoperative chemotherapy seems to impair axillary evaluation by SN biopsy and should be used cautiously in this subset of patients.

Adult↗
PubMed2002

Relation between medial temporal atrophy and functional brain activity during memory processing in Alzheimer's disease: a combined MRI and SPECT study.

OBJECTIVE: To investigate the relation between atrophy of the hippocampal region and brain functional patterns during episodic memory processing in Alzheimer's disease. PATIENTS AND METHODS: Whole brain structural magnetic resonance imaging (MRI) data and single photon emission computed tomography (SPECT) measures of regional cerebral blood flow (rCBF) were obtained during a verbal recognition memory task in nine subjects with mild Alzheimer's disease and 10 elderly healthy controls. Using the statistical parametric mapping approach, voxel based comparisons were made on the MRI data to identify clusters of significantly reduced grey matter concentrations in the hippocampal region in the Alzheimer patients relative to the controls. The mean grey matter density in the voxel cluster of greatest hippocampal atrophy was extracted for each Alzheimer subject. This measure was used to investigate, on a voxel by voxel basis, the presence of significant correlations between the degree of hippocampal atrophy and the rCBF SPECT measures obtained during the memory task. RESULTS: Direct correlations were detected between the hippocampal grey matter density and rCBF values in voxel clusters located bilaterally in the temporal neocortex, in the left medial temporal region, and in the left posterior cingulate cortex during the memory task in the Alzheimer's disease group (p < 0.001). Conversely, measures of hippocampal atrophy were negatively correlated with rCBF values in voxel clusters located in the frontal lobes, involving the right and left inferior frontal gyri and the insula (p < 0.001). CONCLUSIONS: Hippocampal atrophic changes in Alzheimer's disease are associated with reduced functional activity in limbic and associative temporal regions during episodic memory processing, but with increased activity in frontal areas, possibly on a compensatory basis.

Alzheimer Disease↗
PubMed2001

Regional cerebral blood flow abnormalities in early-onset obsessive-compulsive disorder: an exploratory SPECT study.

OBJECTIVE: Recent epidemiological and clinical data suggest that obsessive-compulsive disorder (OCD) may be subtyped according the age of onset of obsessive-compulsive symptoms. The regional cerebral blood flow (rCBF) single photon emission computed tomography (SPECT) technique was used to investigate whether the pathophysiology of OCD differs between early- and late-onset OCD subjects. METHOD: Resting rCBF was measured in 13 early-onset (<10 years) and 13 late-onset (>12 years) adult OCD subjects and in 22 healthy controls. Voxel-based rCBF comparisons were performed with statistical parametric mapping. RESULTS: Early-onset OCD cases showed decreased rCBF in the right thalamus, left anterior cingulate cortex, and bilateral inferior prefrontal cortex relative to late-onset subjects (p < .0005, uncorrected for multiple comparisons). Relative to controls, early-onset cases had decreased left anterior cingulate and right orbitofrontal rCBF, and increased rCBF in the right cerebellum, whereas late-onset subjects showed reduced right orbitofrontal rCBF and increased rCBF in the left precuneus. In early-onset subjects only, severity of obsessive-compulsive symptoms correlated positively with left orbitofrontal rCBF. CONCLUSIONS: rCBF differences in frontal-subcortical circuits between early-onset and late-onset OCD subjects were found, both in location and direction of changes. These results provide preliminary evidence that brain mechanisms in OCD may differ depending on the age at which symptoms are first expressed.

Adolescent↗
PubMed2001

Protective effect of metronidazole on uncoupling mitochondrial oxidative phosphorylation induced by NSAID: a new mechanism.

BACKGROUND: The pathogenesis of non-steroidal anti-inflammatory drug (NSAID) enteropathy is complex. It involves uncoupling of mitochondrial oxidative phosphorylation which alters the intercellular junction and increases intestinal permeability with consequent intestinal damage. Metronidazole diminishes the inflammation induced by indomethacin but the mechanisms remain speculative. A direct effect on luminal bacteria has traditionally been thought to account for the protective effect of metronidazole. However, a protective effect of metronidazole on mitochondrial oxidative phosphorylation has never been tested. AIMS: To assess the protective effect of metronidazole on mitochondrial uncoupling induced by indomethacin and also on the increased intestinal permeability and macroscopic damage. MATERIAL AND METHODS: The protective effect of metronidazole was evaluated in rats given indomethacin; a macroscopic score was devised to quantify intestinal lesions, and intestinal permeability was measured by means of (51)Cr-ethylenediaminetetraacetic acid. The protective effect of metronidazole against mitochondrial uncoupling induced by indomethacin was assessed using isolated coupled rat liver mitochondria obtained from rats pretreated with metronidazole or saline. RESULTS: Metronidazole significantly reduced the macroscopic intestinal damage and increase in intestinal permeability induced by indomethacin; furthermore, at the mitochondrial level, it significantly reduced the increase in oxygen consumption in state 4 induced by indomethacin and caused less reduction of the respiratory control rate. CONCLUSION: Our study confirmed the beneficial effects of metronidazole on intestinal damage and intestinal permeability, and demonstrated, for the first time, a direct protective effect of metronidazole on uncoupling of mitochondrial oxidative phosphorylation caused by NSAIDs.

Animals↗
PubMed2001

Involuntary hand levitation associated with parietal damage: another alien hand syndrome.

The alien hand syndrome (AHS) usually consists of an autonomous motor activity perceived as an involuntary and purposeful movement, with a feeling of foreignness of the involved limb, commonly associated with a failure to recognise ownership of the limb in the absence of visual clues. It has been described in association to lesions of the frontal lobes and corpus callosum. However, parietal damage can promote an involuntary, but purposeless, hand levitation, which, sometimes, resembles AHS. In the present study, four patients (cortico-basal ganglionic degeneration - n=2; Alzheimer's disease - n=1 and parietal stroke - n=1) who developed alien hand motor behaviour and whose CT, MRI and/or SPECT have disclosed a major contralateral parietal damage or dysfunction are described. These results reinforce the idea that parietal lobe lesions may also play a role in some patients with purposeless involuntary limb levitation, which is different from the classic forms of AHS.

Aged↗
PubMed2000

A voxel-based investigation of regional cerebral blood flow abnormalities in obsessive-compulsive disorder using single photon emission computed tomography (SPECT).

Several functional imaging studies have reported abnormalities of the orbitofrontal and anterior cingulate cortices, striatum and thalamus in obsessive-compulsive disorder (OCD). These studies have often been limited by small patient samples and image analysis methods that rely on region-of-interest (ROI) approaches. We have assessed resting regional cerebral blood flow with 99mTc-ECD SPECT in 26 unmedicated OCD patients and 22 healthy control subjects using the voxel-based Statistical Parametric Mapping method for data analysis. We found a significantly reduced ECD uptake in OCD patients relative to the control subjects in the right lateral orbitofrontal cortex, and in the left dorsal anterior cingulate cortex (P<0.001 two-tailed, uncorrected for multiple comparisons). There were significant positive correlations in the OCD group between the ECD uptake in the left lateral orbitofrontal cortex and ratings for obsessive-compulsive symptoms (OCS), and between the ECD uptake in the right medial orbitofrontal cortex and the ratings for both OCS and depressive symptoms. There were also unpredicted significant ECD uptake increases in the cerebellum in OCD patients, as well as a negative correlation between posterior cingulate ECD uptake and OCS severity (P<0.05, corrected for multiple testing). These results implicate specific subregions of the orbitofrontal and anterior cingulate cortices in the pathophysiology of OCD, as well as suggesting the involvement of other areas not usually included in ROI-based imaging studies. With the incorporation of voxel-based methods and the use of large patient samples, rCBF-SPECT studies may continue to provide valuable information about the functional anatomy of OCD.

Adult↗
PubMed2000

SPECT in Alzheimer's disease: features associated with bilateral parietotemporal hypoperfusion.

OBJECTIVE: To investigate why bilateral parietotemporal hypoperfusion, the typical SPECT pattern of Alzheimer's disease (AD), occurs in some but not in all patients with probable AD. METHODS: We reviewed the SPECT scans of 220 patients presenting with cognitive impairment. Among them, 104 patients fulfilled NINCDS-ADRDA criteria for probable AD, 48 (32 women) with early onset (before age of 65) and 56 (40 women) with late onset of the symptoms. Dementia severity was assessed by the Mini-Mental State Examination. The SPECT scans were classified by visual inspection blind to clinical diagnoses. RESULTS: Bilateral parietotemporal hypoperfusion was more frequent in patients with severe AD, in those with early onset of the symptoms, and in men. Duration of symptoms, type of gamma-camera or radiopharmaceutical agent used were not associated with this SPECT pattern. CONCLUSION: These findings may be useful in the clinical setting and point to heterogeneity of AD according to age at onset.

Aged↗
PubMed1997

Neuroimaging findings in Rasmussen's syndrome.

Rasmussen's syndrome is a progressive childhood disease of unknown cause characterized by severe epilepsy, hemiparesis, mental deterioration, inflammation of one cerebral hemisphere, and brain atrophy. Computed tomography, single-photon emission computed tomography (SPECT), and magnetic resonance (MR) neuroimaging findings of 8 patients with pathologically confirmed Rasmussen's syndrome were evaluated retrospectively. All patients showed a predominance of the atrophy in the temporoinsular region and cerebral hemispheric alterations on MR images in a similar extension as seen on SPECT studies. Focal increase in regional cerebral blood flow was observed in the 4 patients presenting with epilepsia partialis continua at the time of hexamethylpropyleneamineoxime injection. Extensive cortical hypoperfusion was noted in the other 4 patients who received the injection during the interictal state. Cerebellar functional abnormalities were present in 6 patients, 2 of them with structural damage.

Adolescent↗
PubMed1996

Cardiac and skeletal muscle scintigraphy in dermato- and polymyositis: clinical implications.

To determine the role of scintigraphy in the detection of skeletal and cardiac involvement in dermato- and polymyositis (DM/PM), we studied 30 patients with a confirmed diagnosis of DM/PM (23 females, 7 males; mean age: 35 years). Technetium-99m pyrophosphate (99mTc-PYP) and gallium-67 scans showed similar sensitivity, specificity and accuracy in the detection of skeletal muscle involvement when compared with serum enzymes (70%, 100% and 80%, respectively). Compared with the clinical parameters, 99mTc-PYP showed 70% and 67Ga 65% accuracy. Abnormal PYP cardiac uptake was observed in 57% of patients, whereas abnormal 67Ga cardiac uptake was seen in only 15%. Electrocardiography was abnormal in 40%, rest gated blood pool study in 23%, and chest X-ray in 13%. In conclusion, both 99mTc-PYP and 67Ga can be useful in the detection of the active phase of muscle disease. However, 99mTc-PYP seems to be more effective than 67Ga in the early diagnosis of cardiac involvement.

Adolescent↗
PubMed1996

Gallbladder emptying in normal volunteers. Comparative study between cholescintigraphy and ultrasonography.

To assess the reproducibility of and compare the patterns of gallbladder emptying after a fatty meal stimulus, the authors analyzed 10 healthy fasting volunteers (8 men; mean age, 32 years). Cholescintigraphy was obtained after intravenous injection of 185 MBq of Tc-99m DISIDA. A standardized fatty meal was provided 70 minutes after injection. The ejection fraction was measured sequentially by ultrasound and cholescintigraphy 15, 30, 45, and 60 minutes after eating. All patients had repeat studies within 1-3 weeks. The two methods showed a distinct gallbladder time course of emptying after the fatty meal stimulus. Nuclear medicine showed higher values of gallbladder ejection fraction at 45 and 60 minutes after eating when compared to ultrasound (P < 0.01). The plotted curves, using the four different periods of time, also showed different behavior due mainly to distinct angular coefficients (nuclear medicine, 2.6; ultrasound, 0.9). Good reproducibility of fatty meal-induced gallbladder ejection fraction at 30, 45, and 60 minutes was also observed using both methods. Thus, ultrasound and nuclear medicine are reproducible methods of studying gallbladder dynamics. However, nuclear medicine demonstrated continued excretion of bile at 45 and 60 minutes, whereas ultrasound did not show significant volume variations in these time frames.

Adult↗
PubMed1996

Brain SPECT in dementia. A clinical-scintigraphic correlation.

The aim of this study was to compare the accuracy of computed tomography (CT) and single photon emission computerized tomography (SPECT) in the diagnosis of dementia. Fifty-two patients with clinical diagnosis of dementia and 11 controls were studied. The scans were interpreted by one experienced neuroradiologist and one nuclear radiologist, both blinded to the clinical data. In the diagnosis of dementia, CT and SPECT showed equal sensitivity (82.7%) and statistically similar specificity (63.8 and 81.8%, respectively). The specificity of SPECT in diagnosing Alzheimer's disease (100%) was statistically superior to CT (69%). However, both methods showed similar sensitivity in detecting Alzheimer's disease. In conclusion, SPECT and CT showed similar accuracy in the diagnosis of dementia. The quite high specificity of SPECT in Alzheimer's disease may be useful for confirming that diagnosis, particularly for patients with presenile onset of the disease.

Adult↗
PubMed1995

PET versus SPECT in distinguishing radiation necrosis from tumor recurrence in the brain.

Two cases of postsurgical brain tumor evaluation in which MRI was inconclusive are discussed. Functional imaging techniques, such as FDG-PET and 201TI SPECT, were used in both cases for distinguishing radiation necrosis from tumor recurrence. These methods proved to be complimentary. For Patient 1, FDG-PET showed more limitations compared to 201TI SPECT. FDG-PET results on the other hand, were consistent with the final diagnosis and the SPECT image was false positive for tumor recurrence in Patient 2.

Adult↗
PubMed1995

[Single photon emission tomography in temporal epilepsy: interictal and ictal studies with visual and semi quantitative analysis].

Single photon emission tomography (SPECT) was performed in 27 patients with refractory complex partial seizures from the temporal lobes due to mesial temporal sclerosis. Independent blinded observers assessed the 28 interictal studies and 9 ictal/postictal studies. Visual analysis of interictal studies detected hypoperfusion in 22, ipsilateral to the epileptogenic zone in 19 (67%) and contralateral in 3 (10.7%). Quantified temporal lobe asymmetry, greater than a previously derived normal range, correctly identified the epileptogenic zone in 16 (61.5%) with false lateralization in 4 (15.3%). In all 9 cases in which they were performed, ictal/postictal studies showed hyperperfusion at the region of epileptic focus. In 3 patients with complex partial seizures followed by symmetric generalized tonic-clonic seizures, hyperperfusion restricted to the temporal lobe was demonstrated. In 5 of these patients the interical studies were unable to demonstrate localized changes. There were no significant correlations between SPECT findings and clinical parameters or EEG slowing in the temporal lobes.

Adolescent↗
PubMed1994

MRI and brain spect findings in patients with unilateral temporal lobe epilepsy and normal CT scan.

26 patients with temporal lobe epilepsy clinically documented by several abnormal interictal surface EEGs with typical unitemporal epileptiform activity and a normal CT scan were studied. Interictal 99mTC HMPAO brain SPECT and MRI were performed in all subjects. Abnormalities were shown in 61.5% of MRI (n = 16) and 65.4% of SPECT (n = 17). Hippocampal atrophy associated to a high signal on T2-weighted MRI slices suggesting mesial temporal sclerosis was the main finding (n = 12; 75% of abnormal MRI). MRI correlated well to surface EEG in 50% (n = 13). There was also a good correlation between MRI and SPECT in 30.7% (n = 8). SPECT and EEG were in agreement in 57.7% (n = 15). MRI, SPECT and EEG were congruent in 26.9% (n = 7). These results support the usefulness of interictal brain SPECT and MRI in detecting lateralized abnormalities in temporal lobe epilepsy. On the other hand, in two cases, interictal SPECT correlated poorly with surface EEG. This functional method should not be used isolately in the detection of temporal lobe foci. MRI is more useful than CT as a neuroimaging technique in temporal lobe epilepsy. It may detect small structural lesions and mesial temporal lobe sclerosis which are not easily seen with traditional CT scanning.

Adolescent↗
PubMed1994

Functional significance of MRI defined mesial temporal sclerosis in temporal lobe epilepsy.

The functional significance of MRI-defined mesial temporal sclerosis in temporal lobe epilepsy (TLE) is not completely established. In order to study the possible relationship between signals of mesial temporal sclerosis on MRI and interictal SPECT findings we selected 18 patients with complex partial seizures, unilateral temporal EEG focus and normal CT. The EEG focus was defined by the presence of interictal sharp waves and slow background on several scalp EEG obtained during many years of follow up in all patients and by ictal recordings with sphenoidal electrodes in 12 patients. Group I comprised patients (n = 11) in whom MRI showed mesial temporal sclerosis; group II patients (n = 7) had normal MRIs. All patients were submitted to interictal 99m-Tc HMPAO injections with concomitant EEG monitoring. Lateralized hypoperfusion ipsilateral to the EEG was found in 13 patients (72%). In all Group II and in 6 Group I patients a temporal hypoperfusion was found. This SPECT study showed a higher positivity rate in patients with normal MRI than previously reported. On the other hand, in all these group II patients a neocortical origin of epileptic focus was suspected on clinical or electroencephalographic basis. Positive SPECT findings may be at least as prevalent in neocortical as in mesiolimbic epilepsy.

Adolescent↗
PubMed1992

Brain SPECT in the pre-surgical evaluation of epileptic patients. Preliminary results.

Pre-surgical evaluation of epileptic patients consists of neurological examination, intensive electroencephalographic (EEG) monitoring and anatomical studies (CT and MRI). Functional methods such as PET and SPECT imaging are now used more frequently. We have studied pre-operatively 15 adult epileptic patients (8 female, 7 male) using a rotational scintillation camera interfaced to a dedicated computer. The tomographic images were obtained 15 minutes after intravenous injection of 99mTc-HMPAO. All had MRI scanning and intensive EEG monitoring which generally included seizure recording. Five patients had progressive lesions (3 meningiomas, 2 astrocytomas). In 10 patients, neuroradiological studies did not show the presence of progressive lesions (2 normal scans and 8 cases with inactive lesions). Two patients with meningioma showed hypoperfusion at the lesion site while the third patient had a marked hyperperfusion which might correlate with the clinical diagnosis of epilepsia partialis continua. In the astrocytoma patients SPECT scans showed hypoperfusion at the lesion site. Data obtained from the 10 patients without progressive CNS lesions showed: (a) in 4, SPECT findings correlated well with the anatomical findings; (b) in 5 instances, SPECT was able to disclose additional functional deficits; (c) in one case, there was no SPECT correlate of a discrete anatomical lesion. In 5 of these cases with no progressive lesions (n = 10) SPECT findings were useful as a complementary tool in determining the clinical or surgical management of these patients. Despite the small number and heterogenicity of the present sample, SPECT seems to be an useful tool as part of the clinical workup of epileptic patients who are candidates for epilepsy surgery.

Adult↗
PubMed1991

Quantification of ocular inflammation with technetium-99m glucoheptonate.

Histological and morphometric evaluation of ocular inflammation is difficult, particularly when there is extensive ocular involvement with abscess formation and necrosis. A quantitative imaging procedure applicable to humans would be important clinically. To establish such a procedure, turpentine-induced ocular inflammation was obtained by subconjunctival injection in the right eye of 55 rabbits. The left eye was used as control and injected with a volume of saline equal to the volume of turpentine in the right eye. Volumes of turpentine or saline were 0.02, 0.04, 0.06, 0.2 and 0.6 ml, and the rabbits were divided into groups 1-5, according to these volumes. Imaging was performed 48 h after turpentine injection and 6 h after intravenous injection of 10 mCi of technetium-99m glucoheptonate (99mTc-GH). An inflammatory reaction index (IRI), defined as the ratio of counts of the right eye divided by counts of the left eye, was used. IRIs were proportional to the degree of inflammation and allowed the distinction of 3 subgroups: one represented by group 4, one by group 5 and one by groups 1, 2 and 3. This method of quantification of ocular inflammatory processes using 99mTc-GH is original, rapid, non-invasive, reproducible and safe, although unable to differentiate inflammatory processes caused by doses of turpentine which are very small and close to each other. It is conceivable that its application to humans will bring new insight into the ocular inflammatory process and response to therapy.

Animals↗