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F Lomeña

Publications and source records attributed to F Lomeña.

At least 55 records · Page 3Linked to original sources
PubMed1996

Baseline, visual deprivation and visual stimulation 99TCm-HMPAO-related changes in visual cortex can be detected with a single-head SPET system.

To determine the sensitivity of 99TCm-hexamethylpropylene amine oxime (99TCm-HMPAO) and a single-head SPET (single photon emission tomography) system in the detection of perfusion changes in the visual cortex due to different visual conditions, six normal healthy volunteers were studied under conditions of visual deprivation (blindfolded), visual stimulation (stroboscopic light) and baseline (dim light and eyes open). Visual cortex/whole-brain activity ratios, and the percentage of activity change between the different visual conditions were calculated after three-dimensional realignment of the images. The activity in the visual cortex was higher during visual stimulation than during the visual deprivation (P = 0.002, 17.6 +/- 8.6% increase) and baseline conditions (P = 0.009, 8.8 +/- 5.6% increase). Furthermore, the activity in the visual cortex was lower during the visual deprivation than in the baseline condition (P = 0.001, 8.1 +/- 2.9% decrease). 99TCm-HMPAO SPET, even with a single-head system, is capable of detecting changes in rCBF in the striate cortex, not only between conditions of visual stimulation and deprivation, but also between these two conditions and the baseline state.

Adult↗
PubMed1996

Salbutamol reduces pulmonary neutrophil sequestration of platelet-activating factor in humans.

To investigate whether salbutamol inhibits platelet-activating factor (PAF)-induced neutrophil sequestration in the lungs, we studied eight nonatopic, nonsmoking, healthy subjects (six men; aged 27.0 +/- 1.5 (SE) yr) with PAF-induced bronchial response. Prior to PAF challenge (24 micrograms), they inhaled either salbutamol (300 micrograms) or placebo in a randomized, double-blind, crossover manner two weeks apart. Respiratory system resistance (Rrs), arterial blood gases, and neutrophil counts were measured 4, 8, 12 and 30 min after PAF. Neutrophil kinetics in the lungs were assessed by tracking autologous 99mTc-erythrocytes and 111in-neutrophils. Compared with salbutamol, arterial blood neutrophil counts fell (p < 0.04) maximally at 4 min after PAF, followed by a mild rebound neutrophilia, whereas Rrs increased (p < 0.01) and Pao2 decreased (p < 0.05) at 4 min only. The intrapulmonary activity of 111in-neutrophils after pretreatment with placebo was higher compared with salbutamol (1.98 +/- 0.15 versus 1.33 +/- 0.23 cps/mCi/pixel) (p < 0.01) although both their initial sequestration (first-pass) and subsequent washout were not significantly different. Inhaled salbutamol blocks pulmonary neutrophil sequestration and lung function abnormalities following PAF challenge in humans.

Administration, Inhalation↗
PubMed1994

Correlation of MRI hippocampal volume analysis, video/EEG monitoring and inter- and postictal single photon emission tomography in refractory focal epilepsy.

The effectiveness of surgery in patients with refractory complex partial seizures depends on accurate localisation of the epileptogenic zone. To assess the correlation between magnetic resonance imaging (MRI) hippocampal volume measurements. Tc 99m-hexamethyl-propyleneamineoxime inter- and postictal single photon emission computed tomography (SPECT) and clinico-electrophysiological (video/EEG) localisation of the epileptogenic zone we prospectively studied 16 consecutive patients with refractory complex partial seizures and no significant abnormality on standard MRI. Each test was interpreted blindly by independent observers. Eight patients (50%) had asymmetrical hippocampal volumes indicative of unilateral atrophy; correlation with the video/EEG and postical SPECT changes was very high (100% with definitive video/EEG localisation, 75% with interictal EEG and 83% with postictal SPECT). Moreover, the left/right hippocampal ratio was able to differentiate temporal from extratemporal video/EEG localisations. Postictal SPECT showed regional lateralised changes in 9 (64%) of 14 technically satisfactory studies. Disagreement between the video/EEG and postictal SPECT was seen with two extratemporal and one bitemporal foci.

Adolescent↗
PubMed1994

Prefrontal dysfunction in young acute neuroleptic-naive schizophrenic patients: a resting and activation SPECT study.

Regional cerebral blood flow (rCBF) was measured with single photon emission computed tomography (SPECT) in six neuroleptic-naive, young, acute schizophrenic patients and six normal control subjects. We evaluated rCBF changes in prefrontal areas at rest and during a prefrontal activation task, the Wisconsin Card Sorting Test (WCST). Schizophrenic patients had significantly higher prefrontal blood flow than did control subjects during the resting conditions. During activation, the control group showed significant increases in prefrontal blood flow, whereas the schizophrenic group did not. These results suggest that at rest there is no evidence of hypofrontality, whereas hyperfrontality seems to be the most frequent pattern in our selected sample of young acute neuroleptic-naive schizophrenic patients. Furthermore, schizophrenic patients seem to be unable to increase prefrontal blood flow under conditions that challenge the prefrontal cortex.

Adult↗
PubMed1994

Procedure for red blood cell labelling with 99mTc-HMPAO. Methodology and quality control.

We present here results on the labelling of red blood cells with 99mTc-HMPAO as an alternative method to the usual in vitro technique. Anticoagulant agents, the labelling medium with plasma, and the lapse of time between 99mTc-HMPAO preparation and labelling are the main factors which affect the efficiency of the procedure. A 93.9 +/- 2.3% labelling yield was obtained with freshly prepared 99mTc-HMPAO. In vitro (tracer elution of 4.3 +/- 1.2% at 60 mins) and in vivo (percentage of plasma activity at 60 mins, 7.8 +/- 2.8%) stability of the label, as well as image quality, qualify 99mTc-HMPAO labelled red blood cells as a suitable agent for clinical use.

Erythrocytes↗
PubMed1992

Pulmonary aspiration of gastric contents in patients receiving mechanical ventilation: the effect of body position.

OBJECTIVE: To determine if the semirecumbent position (45-degree angle) decreases aspiration of gastric contents to the airways in intubated and mechanically ventilated patients. DESIGN: A randomized, two-period crossover trial. SETTING: Respiratory intensive care unit. PATIENTS: Nineteen patients requiring intubation and mechanical ventilation. INTERVENTIONS: Patients were studied in the supine and semirecumbent positions on two separate days. MEASUREMENTS: After technetium (Tc)-99m sulphur colloid labeling of gastric contents, sequential radioactive counts in endobronchial secretions were measured at 30-minute intervals over a 5-hour period. Samples of endobronchial secretions, gastric juice, and pharyngeal contents were obtained for qualitative bacterial cultures. RESULTS: Mean radioactive counts in endobronchial secretions were higher in samples obtained while patients were in the supine position than in those obtained while patients were in the semirecumbent position (4154 cpm compared with 954 cpm; P = 0.036). Moreover, the aspiration pattern was time-dependent for each position: For the supine position, radioactivity was 298 cpm at 30 min and 2592 cpm at 300 min (P = 0.013); for the semirecumbent position, radioactivity was 103 cpm at 30 min and 216 cpm at 300 min (P = 0.04). The same microorganisms were isolated from stomach, pharynx, and endobronchial samples in 32% of studies done while patients were semirecumbent and in 68% of studies done while patients were in the supine position. CONCLUSIONS: We conclude that the supine position and length of time the patient is kept in this position are potential risk factors for aspiration of gastric contents. Elevating the head of the bed for patients who can tolerate the semirecumbent position may be a simple, no-cost prophylactic measure.

Female↗
PubMed1992

Radioimmunoscintigraphy of colorectal carcinoma with a 99Tcm-labelled anti-CEA monoclonal antibody (BW 431/26).

Radioimmunoscintigraphy (RIS) with BW 431/26 monoclonal antibody (MoAb) labelled with 99Tcm (962 MBq) has been performed in 64 patients with colorectal carcinoma, one of them with two independent tumours. The group consisted of 46 primary lesions, 15 pelvic recurrences and four suspected recurrences which were shown to be liver metastases. Imaging of liver was obtained in all patients, but surgical liver examination was performed in only 56 of them. Planar scans were obtained at 4 and 24 h postinjection. Tomographic images were also performed in five patients. The final diagnosis was confirmed in all patients by their clinical course and by findings at surgery and pathology. A comparative study between the RIS results and the final diagnosis gave a global sensitivity in primary tumours and pelvic recurrences of 59.7% with an accuracy of 59.0%. When rectal tumours were excluded, the results were 81.1 and 84.9%, respectively. In liver metastases the sensitivity was 50%, with an accuracy of 85.7% and a specificity of 100%. No correlation has been found between CEA serum levels and lesion detection. In conclusion, RIS is a useful technique for the study and localization of colorectal tumours, being also indicated in patients with normal carcinoembryonic antigen (CEA) serum levels and clinical suspicion of illness.

Aged↗
PubMed1991

Reflex sympathetic dystrophy syndrome of the lower limbs in renal transplant patients treated with cyclosporin A.

In a 36-month period, 240 patients at our institution received kidney transplants from cadaver donors. Cyclosporin A (CsA) was used as the initial immunosuppressive therapy. Seven patients (5 men and 2 women) developed severe pain, periarticular soft tissue swelling with no effusion, and vasomotor changes in affected areas. Although articular mobility was conserved, most of the patients had great difficulty in walking. A patchy osteoporotic pattern was seen radiographically and increased uptake of 99mtechnetium with a periarticular distribution in the clinically affected areas were found. All of these symptoms and radiographic and scintigraphic signs are compatible with definite reflex sympathetic dystrophy syndrome (RSDS). Articular symptoms began within 3 months after kidney transplantation in all patients; all but 1 patient had plasma CsA levels greater than 200 ng/ml at that time. When the dosage of CsA was reduced, there was concomitant improvement in the RSDS, which appeared when the plasma CsA levels declined to less than 200 ng/ml. The mean duration of the clinical symptoms of RSDS was 8 months. We believe RSDS should be added to the list of complications that may appear in kidney transplant patients who receive CsA treatment.

Adult↗
PubMed1991

99Tcm-HMPAO leucocyte scintigraphy in the diagnosis of bone infection.

The utility of 99Tcm-HMPAO leucocytes has been studied in combination with 99Tcm-MDP bone scanning in the diagnosis of bone infection in a series of 50 patients with a clinical suspicion of bone infection. Thirty-three patients were referred to our Service from the Department of Orthopaedic Surgery (Group A) and seventeen from the Infectious Disease Unit (Group B). A total of 52 lesion sites were studied. The leucocyte and bone studies were performed within four days. The leucocyte scan was obtained at 30-60 min and 4-6 h after i.v. injection of 370 +/- 74 MBq of 99Tcm-HMPAO leucocytes. After confirming the scintigraphic findings, the results obtained were: Group A, 12 true positive, 21 true negative and 2 false positive; and in Group B, 5 true positive, 9 true negative and 4 false negative. The overall sensitivity was 80.9% with a specificity of 93.7%. Although the high bone marrow activity seen with 99Tcm-HMPAO leucocytes may reduce sensitivity, very good results were obtained in bone infection. The use of 99Tcm means great progress in the radiolabelling of white blood cells in terms of availability and better image quality. The combination of 99Tcm-HMPAO leucocytes and 99Tcm-MDP can be recommended as one of the most suitable methods for use in the diagnosis of bone infection, especially in patients with previous bone disease.

Adolescent↗