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Biomedical subjects

Michael Gabriel

Publications and source records attributed to Michael Gabriel.

At least 19 recordsLinked to original sources
PubMed2006

99mTc-depreotide scintigraphy versus 18F-FDG-PET in the diagnosis of radioiodine-negative thyroid cancer.

BACKGROUND: Papillary and follicular thyroid cancer were found recently to express somatostatin receptors (SSTRs). (99m)Tc-depreotide binds with high affinity to SSTRs 2, 3, and 5. AIM: The aim of this study was to evaluate the feasibility of applying (99m)Tc-depreotide scintigraphy to search for radioiodine-negative thyroid cancer; comparison is made to a standard approach using (18)F-fluorodeoxyglucose-positron emission tomography ((18)F-FDG-PET). PATIENTS AND METHODS: Ten radioiodine-negative patients with suspicion of recurrent or metastatic thyroid cancer were investigated with (99m)Tc-depreotide scintigraphy and (18)F-FDG-PET, performed with a time interval that ranged from 1-8 wk. Locoregional recurrence and metastases were confirmed by ultrasonography and/or computed tomography, together with cytology or histological examination in selected cases. RESULTS: True-positive results were obtained in nine patients (90%) with (99m)Tc-depreotide scintigraphy and in seven patients (70%) with (18)F-FDG-PET. (99m)Tc-depreotide scintigraphy gave better results in terms of detection of recurrent or metastatic disease compared with (18)F-FDG-PET in three patients, whereas (18)F-FDG-PET identified metastatic disease that was not seen with (99m)Tc-depreotide in only one patient. (99m)Tc-depreotide scintigraphy portrayed lesions in three patients with negative morphological imaging. CONCLUSIONS: Results indicate a potential value of (99m)Tc-depreotide scintigraphy for the diagnosis of thyroid cancer in the setting of detectable thyroglobulin and negative radioiodine scan. Furthermore, (99m)Tc-depreotide adds complementary information regarding the SSTR status of lesions, which may be helpful for individual therapy planning in this group of patients, which is hard to manage clinically.

Aged↗
PubMed2006

Collaborative development of the Arrowsmith two node search interface designed for laboratory investigators.

Arrowsmith is a unique computer-assisted strategy designed to assist investigators in detecting biologically-relevant connections between two disparate sets of articles in Medline. This paper describes how an inter-institutional consortium of neuroscientists used the UIC Arrowsmith web interface http://arrowsmith.psych.uic.edu in their daily work and guided the development, refinement and expansion of the system into a suite of tools intended for use by the wider scientific community.

Journal Article↗
PubMed2006

Insular-type component follicular thyroid carcinoma in a 10-year-old girl--case report.

Insular-type carcinoma of the thyroid is a rare form of undifferentiated thyroid cancer. The manifestation of disease occurs mainly in adults and is extremely rare in children. Prognosis of this type of thyroid carcinoma is unfavorable in childhood. Because of its rarity, it is not yet clear whether these tumors carry the same risk of progression. Therapy of choice is total thyroidectomy combined with a cervical lymph node dissection. In children, surgery is associated with a higher risk of recurrent nerve palsy and loss of parathyroid glands than in adults. Therefore, identification and protection of the recurrent laryngeal nerve using electrical neuromonitoring as well as exact preparation of parathyroid glands may reduce these risks. The history of a 10-year-old girl with insular-type thyroid carcinoma is presented. Surgical considerations such as total thyroidectomy vs less-than-total thyroidectomy with unilateral or bilateral cervical lymph node dissection are presented. Prognosis concerning morbidity, pointing out the aspect of electrical neuromonitoring and precaution of parathyroid glands, and survival rate of this extremely rare entity are discussed.

Adenocarcinoma, Follicular↗
PubMed2006

Implementing cash for work programmes in post-tsunami Aceh: experiences and lessons learned.

Cash for work (CFW) programmes are utilised in various disaster and emergency contexts and were a prominent component of the tsunami response in Aceh province, Indonesia. This paper describes Mercy Corps' CFW programme, discusses CFW implementation experiences and provides key recommendations for similar programmes in future emergencies. For the majority of CFW participants and their households, CFW was the only source of household income and 93 per cent of household incomes were attributable to it. The CFW programme empowered displaced populations to return to their communities; 91 per cent of participants indicated that CFW facilitated their return. Other reported psychosocial benefits included providing productive activities and giving communities an opportunity to work together. Mercy Corps' experience in Aceh demonstrates that cash disbursements can be safely delivered in a widespread manner in emergencies, and that when implemented on a short-term basis, can have positive impacts at the individual and community level.

Disasters↗
PubMed2005

Image fusion analysis of (99m)Tc-HYNIC-Tyr(3)-octreotide SPECT and diagnostic CT using an immobilisation device with external markers in patients with endocrine tumours.

PURPOSE: The aim of this study was to assess the value of multimodality imaging using a novel repositioning device with external markers for fusion of single-photon emission computed tomography (SPECT) and computed tomography (CT) images. The additional benefit derived from this methodological approach was analysed in comparison with SPECT and diagnostic CT alone in terms of detection rate, reliability and anatomical assignment of abnormal findings with SPECT. METHODS: Fifty-three patients (30 males, 23 females) with known or suspected endocrine tumours were studied. Clinical indications for somatostatin receptor (SSTR) scintigraphy (SPECT/CT image fusion) included staging of newly diagnosed tumours (n=14) and detection of unknown primary tumour in the presence of clinical and/or biochemical suspicion of neuroendocrine malignancy (n=20). Follow-up studies after therapy were performed in 19 patients. A mean activity of 400 MBq of (99m)Tc-EDDA/HYNIC-Tyr(3)-octreotide was given intravenously. SPECT using a dual-detector scintillation camera and diagnostic multi-detector CT were sequentially performed. To ensure reproducible positioning, patients were fixed in an individualised vacuum mattress with modality-specific external markers for co-registration. SPECT and CT data were initially interpreted separately and the fused images were interpreted jointly in consensus by nuclear medicine and diagnostic radiology physicians. RESULTS: SPECT was true-positive (TP) in 18 patients, true-negative (TN) in 16, false-negative (FN) in ten and false-positive (FP) in nine; CT was TP in 18 patients, TN in 21, FP in ten and FN in four. With image fusion (SPECT and CT), the scan result was TP in 27 patients (50.9%), TN in 25 patients (47.2%) and FN in one patient, this FN result being caused by multiple small liver metastases; sensitivity was 95% and specificity, 100%. The difference between SPECT and SPECT/CT was statistically as significant as the difference between CT and SPECT/CT image fusion (P<0.001). Twenty-seven abnormal SPECT findings in 17 patients could not be initially assigned to organs, but were clearly delineated after image fusion. In 21 patients (40%), clinically relevant information was obtained by image fusion as compared with SPECT alone. CONCLUSION: Co-registration of SPECT and diagnostic CT using a cost-effective immobilisation device provides excellent accuracy for tumour detection of endocrine malignancies and is superior to SPECT and CT alone. Image fusion reduces false positive results and can detect additional lesions. Anatomical information provided by CT enables precise localisation of abnormalities observed in SPECT.

Adult↗
PubMed2005

Cingulate cortical coding of context-dependent latent inhibition.

Neuronal activity of the auditory thalamus, amygdala, cingulate cortex, and substantia nigra was recorded during the administration of a behavioral test for latent inhibition (LI) or the retardation of behavioral conditioning because of preexposure of the conditional stimulus (CS). Following CS preexposure, both the preexposed CS and a control CS predicted avoidable footshock. LI occurred as significantly fewer avoidance conditioned avoidance responses after the preexposed CS than after the control CS. Attenuation of neuronal responses to the preexposed CS, or neural LI, occurred in all monitored areas. One group of subjects (Oryctolagus cuniculus) then received context extinction, and additional groups experienced novel context exposure or handling. Context extinction enhanced behavioral responding to the preexposed CS, eliminating LI. Context extinction also eliminated cingulate cortical neural LI by enhancing posterior cingulate cortical responses to the preexposed CS and attenuating anterior cingulate cortical responses to the control CS. Present and past results are interpreted to indicate that LI is (a) a failure of response retrieval and/or expression mediated by interfering CS-context associations and (b) a product of interactions of the posterior cingulate cortex and the hippocampus.

Acoustic Stimulation↗
PubMed2004

Independent generation of theta rhythm in the hippocampus and posterior cingulate cortex.

Theta rhythmicity of field potentials recorded in the posterior cingulate cortex is thought to have a septo-hippocampal origin, principally because phase reversal of this theta occurs in the dorsal hippocampus, but not in the posterior cingulate cortex. In the current study, theta activity of cue-elicited field potentials and multiple unit activity in posterior cingulate cortical areas 29b and 29c/d, and in the associated anterior ventral (AV) thalamic nucleus, was monitored while rabbits underwent discriminative avoidance conditioning. Theta activity in the field potentials occurred during training in areas 29b and 29c/d, and was severely attenuated by electrolytic lesions in the dorsal hippocampus. Significant theta rhythmicity was not evident in multiple unit activity recorded from area 29c/d, either in lesioned or sham-operated subjects. However, theta-like modulation was evident in the multiple unit activity of area 29b, and in the AV thalamic nucleus, occurring in synchrony with the field potential oscillations. Theta rhythmicity of unit activity in these areas was unaffected by dorsal hippocampal lesions. These results suggest that theta-frequency oscillations apparent in posterior cingulate cortical field potentials are volume-conducted from the dorsal hippocampus, but that theta-like unit activity in posterior cingulate cortical area 29b and in the AV thalamic nucleus occurs independently of hippocampal theta.

Analysis of Variance↗
PubMed2004

Accuracy of preoperative pinhole subtraction single photon emission computed tomography for patients with primary and recurrent hyperparathyroidism in an endemic goiter area.

PURPOSE: Bilateral parathyroid exploration is still the standard therapeutic procedure for primary and recurrent hyperparathyroidism (HPTH). Since a unilateral surgical strategy that reduces surgical complications should not increase the risk of missing enlarged parathyroid glands, reliable preoperative imaging is the first requirement for this approach. This study was conducted to assess the accuracy of preoperative (99m)TcO(4)-(201)T1 pinhole subtraction single photon emission computed tomography (SPECT) compared with sonography. METHODS: The study population consisted of 15 patients with primary (n = 13) or recurrent (n = 2) HPTH who underwent preoperative (99m)TcO(4)-(201)T1 pinhole subtraction SPECT. Preoperative sonography was also done in 14 of these patients. RESULTS: (99m)TcO(4)-(201)T1 pinhole subtraction SPECT was significantly more accurate than sonography. It had an overall accuracy of 80% in detection of enlarged parathyroid glands. The accuracy of localization increased to 92.3% in patients with solitary adenomas, and to 100% in those with solitary adenomas and no previous parathyroid exploration. CONCLUSIONS: The high accuracy of preoperative localization with (99m)TcO(4)-(201)T1 pinhole subtraction SPECT in patients with primary and recurrent HPTH allows for an imaging-guided unilateral operative strategy in most patients, even those with concomitant nodular goiters. This may reduce the risk of surgical complications and expand the use of minimally invasive techniques in parathyroid surgery.

Adenoma↗
PubMed2004

Computed axial tomography-MIBI image fusion for preoperative localization in primary hyperparathyroidism.

BACKGROUND: An imaging-guided unilateral surgical approach in patients with primary hyperparathyroidism (HPTH) requires reliable preoperative localization procedures. Using present imaging techniques, 60% to 80% of patients with primary HPTH can be treated successfully with limited surgery. Thus, further improvement of diagnostic accuracy is required. Computed axial tomography (CAT)-MIBI image fusion was introduced as a new technique for localizing enlarged parathyroid glands. We describe the new method and present its first results. METHODS: Six consecutive patients with primary HPTH underwent CAT-MIBI image fusion for preoperative parathyroid localization. CAT and technetium-99m-sestamibi scan were performed separately. The patient's head and neck were fixed with the noninvasive Vogele-Bale-Hohner Head Holder (VBH HeadFIX; Medical Intelligence, Schwabmünchen, Germany) and the BodyFIX (Medical Intelligence) vacuum cushion. Radiographic and scintigraphic markers were mounted at the head holder and the patient. CAT and MIBI images were fused by overlaying radiographic markers using a commercial software and workstation. RESULTS: In 5 patients, localization and dimension of the solitary adenomas were exactly predicted. In 1 patient with multiglandular disease (3 enlarged glands), CAT-MIBI image fusion was not able to predict multiple gland involvement. However, in a retrospective analysis of the localization study, the other two enlarged parathyroid glands could be correctly identified regarding their site and size. CONCLUSIONS: First results of CAT-MIBI image fusion are promising. The new technique provides a higher image resolution and better delimitation of enlarged parathyroid glands and adjacent anatomic structures than conventional scintigraphic methods.

Aged↗
PubMed2004

CT-MIBI image fusion: a new preoperative localization technique for primary, recurrent, and persistent hyperparathyroidism.

BACKGROUND: Successful minimally invasive or imaging-guided operations in patients with primary, recurrent, and persistent hyperparathyroidism are based on the reliability of preoperative parathyroid localization studies. The CT-MIBI image fusion promises a higher diagnostic accuracy than current imaging procedures. The aim of our study was to assess its reliability in correctly detecting enlarged parathyroid glands. METHODS: In a prospective study 24 consecutive patients underwent CT-MIBI image fusion as preoperative parathyroid localization procedure. The results of technetium 99m sestamibi single photon emission computed tomography (MIBI-SPECT) alone, today the standard method in parathyroid imaging, and CT-MIBI image fusion were analyzed by a blinded reviewer, and the imaging results were compared with the intraoperative findings. RESULTS: For CT-MIBI image fusion a sensitivity of 93% and a specificity of 100% in correctly detecting the position of enlarged parathyroid glands was calculated and compared with a sensitivity of MIBI-SPECT of 31% and a specificity of 87% (P<.001). This new imaging technique enabled us to successfully treat 22 of our patients (92%) with imaging-guided surgery. Twenty (83%) underwent unilateral or minimally invasive operations. CONCLUSIONS: CT-MIBI image fusion appears to be superior to MIBI-SPECT in preoperative parathyroid imaging. CT-MIBI image fusion can be performed on existing CT- and MIBI-SPECT units. We recommend this method for preoperative localization in patients with primary, recurrent and persistent hyperparathyroidism.

Adult↗
PubMed2004

Effects of conditioning during amygdalar inactivation on training-induced neuronal plasticity in the medial geniculate nucleus and cingulate cortex in rabbits (Oryctolagus cuniculus).

This study addressed the amygdala's role in avoidance conditioning in rabbits (Oryctolagus cuniculus). Intra-amygdalar muscimol infusion before 60 or 120 conditioning trials blocked training-induced neuronal activity (TIA) in the medial geniculate (MG) nucleus. One hundred twenty trials with muscimol blocked TIA permanently, during conditioning with muscimol and then later without muscimol; 60 trials with muscimol blocked TIA only when muscimol was present. Cingulate cortical TIA was blocked only when muscimol was present. Behavioral learning did not occur with muscimol, but later learning was facilitated (i.e., savings occurred) in rabbits initially given muscimol plus training. These results define the time period wherein amygdalar processes initiate TIA in the MG nucleus and suggest that distinct forms of amygdalar processes induce TIA in the MG nucleus and cingulate cortex.

Action Potentials↗
PubMed2004

Fornix lesions impair context-related cingulothalamic neuronal patterns and concurrent discrimination learning in rabbits (Oryctolagus cuniculus).

Cingulothalamic neurons develop topographic patterns of cue-elicited neuronal activity during discrimination learning. These patterns are context-related and are degraded by hippocampal lesions, suggesting that hippocampal modulation of cingulothalamic activity results in the expression of the patterns, which could promote the retrieval of context-appropriate responses and memories. This hypothesis was tested by training rabbits (Oryctolagus cuniculus) with fornix lesions concurrently on two discrimination tasks (approach and avoidance) in different contexts. Because the same conditioned stimuli were used for both tasks, contextual information was critical for overcoming intertask interference during concurrent task acquisition. The lesions degraded the topographic patterns and significantly impaired concurrent learning, suggesting that hippocampal-cingulothalamic interactions and the resulting topographic patterns are critical for processing contextual information needed to defeat interference.

Action Potentials↗
PubMed2004

99mTc-N4-[Tyr3]Octreotate Versus 99mTc-EDDA/HYNIC-[Tyr3]Octreotide: an intrapatient comparison of two novel Technetium-99m labeled tracers for somatostatin receptor scintigraphy.

Tetraamine-[Tyr3]octreotate (Demotate) is a somatostatin (SST) analogue that can be easily labeled with 99mTc at high specific activities and showed promising preclinical properties for SST receptor scintigraphy. This study reports on the first intra-patient comparison of 99mTc-Demotate and another 99mTc-labeled SST analogue, 99mTc-EDDA/HYNIC-TOC (HYNIC-TOC). Five patients with carcinoid tumors (n = 2) and endocrine pancreatic tumors (n = 3) were investigated with both radiopharmaceuticals. 99mTc-Demotate rapidly visualized somatostatin receptor positive tumors as early as 15 minutes post-injection (p.i.) with maximum tumor uptake and tumor/organ ratios already 1 hour p.i. Organs of predominant physiological uptake were the spleen and the kidneys with no intestinal excretion detectable up to 24 hours. 99mTc-Demotate exhibited faster pharmacokinetic properties compared to HYNIC-TOC. Tumor/organ ratios at equivalent time points were higher or comparable for 99mTc-Demotate in three patients with a matching scan result. Equivocal findings were observed in two patients, i.e. comparable uptake behavior in larger lesions with differences in smaller ones. 99mTc-Demotate is a promising agent for somatostatin receptor scintigraphy providing images of excellent quality as early as 1 hour after injection.

Aged↗
PubMed2004

An individual dosimetric approach to 153Sm-EDTMP therapy for pain palliation in bone metastases in correlation with clinical results.

BACKGROUND: The clinical results of therapy using 153Sm ethylenediamine-N,N,N'N'-tetrakis(methylene phosphonic acid) (153Sm-EDTMP) were correlated with radiation dose indices in metastases, with the intention of improving the therapeutic efficacy. METHODS: Fifty-six patients with disseminated bone metastases were treated. Prior to therapy, whole-body scans and single photon emission computed tomography (SPECT) of the trunk were performed. Whole-body retention of 99mTc labelled phosphonates was compared with 153Sm-EDTMP retention after therapy. Estimations of the volumes of bone lesions were done by SPECT. Assuming a solid tumour but a thin metabolically active boundary zone between tumour and healthy bone that absorbed the beta radiation, we estimated an 'irradiated volume' by using a spherical shell model of 6 mm thickness. Local tracer uptake in lesions was assessed by regions of interest techniques on conjugated views of whole-body scans with homogeneous attenuation correction. Calculation of the dose index by applying the Medical Internal Radiation Dosimetry (MIRD) scheme was done retrospectively in 10 patients and prospectively in 22 cases. Depending on changes in pain/mobility scores, results were classified as 'very good', 'good' and 'no response'. RESULTS: A mean dose index > or =10 per lesion was estimated under the condition of a homogeneous uptake within the idealized, spherical, tumour volume. Assuming that the uptake of the radiopharmaceutical occurs mostly within an outer shell of the tumour, dose indices to this 'irradiated volume' can increase to more than twice that value. CONCLUSION: Very good clinical results for bone pain palliation by using 153Sm-EDTMP therapy could be found in patients receiving a dose index >15 per lesion. Even this approximate dosimetric approach, considering the individual differences in tumour spread and the varying intensity of 153Sm uptake, could improve the impact of 153Sm-EDTMP for pain control in cancer patients.

Aged↗
PubMed2003

99mTc-EDDA/HYNIC-TOC and (18)F-FDG in thyroid cancer patients with negative (131)I whole-body scans.

Several studies have reported on the expression of somatostatin receptors in patients with differentiated thyroid cancer (DTC). The aim of this study was to evaluate the imaging abilities of a recently developed technetium-99m labelled somatostatin analogue, (99m)Tc-EDDA/HYNIC-TOC ((99m)Tc-TOC), in terms of precise localisation of disease. The study population comprised 54 patients (24 men, 30 women; age range 22-90 years) with histologically confirmed DTC who presented with recurrent or persistent disease as indicated by elevated Tg levels after initial treatment. All patients were negative on the iodine-131 post-therapy whole-body scans. Fluorine-18 fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) was performed in a subgroup of 36 patients. The study population consisted of two groups: Group A ( n=22) comprised patients with disease recurrence as shown by elevated Tg levels but without detectable pathology. In group B ( n=32), pre-existing lesions were known. Among the 54 cases, SSTR scintigraphy was true positive in 33 (61.1%), true negative in 4 (7.4%) and false negative in 17 (31.5%) cases, which resulted in a sensitivity of 66%. A total of 138 tumour foci were localised in 33 patients. The fraction of true positive (99m)Tc-TOC findings was positively correlated ( P<0.01) with elevated Tg levels (higher than 30 ng/ml). Despite two false positive findings, analysis on a lesion basis demonstrated better diagnostic efficacy with (18)F-FDG PET ( P<0.001); however, it also revealed substantial agreement between the imaging techniques [Cohen's kappa of 0.62 (0.47-0.78)]. In conclusion, scintigraphy with (99m)Tc-TOC might be a promising tool for treatment planning; it is easy to perform and showed sufficient accuracy for localisation diagnostics in thyroid cancer patients with recurrent or metastatic disease.

Adult↗
PubMed2003

99mTc-Demotate 1: first data in tumour patients-results of a pilot/phase I study.

Somatostatin receptor (SSTR) scintigraphy with indium-111 DTPA-octreotide has become a routine diagnostic procedure in oncology. However, it suffers some drawbacks concerning the limited availability, suboptimal imaging properties and elevated radiation burden of (111)In. We have recently been involved in the development of a new tetraamine-functionalised [Tyr(3)]octreotate derivative (Demotate 1) that can be easily labelled with technetium-99m at high specific activities. (99m)Tc-Demotate 1 showed promising properties in preclinical studies. In this study we report on the first experience with (99m)Tc-Demotate 1 in patients. Six patients (mean age 56 years) with carcinoid tumours ( n=2) or endocrine pancreatic tumours ( n=4) with previously positive SSTR scintigraphy were enrolled in the study. Patients were injected with 500-600 MBq (99m)Tc-Demotate 1. Clinical and laboratory parameters were controlled up to 3 months p.i. Blood samples were taken at various time points up to 24 h p.i., and urine was collected up to 24 h. Whole-body images were acquired at 15-30 min, 1-2 h, 4 h and 24 h p.i. with additional single-photon emission tomography imaging at 1-4 h. Blood excretion was very rapid, with <2%ID in plasma after 1 h, and urinary excretion <20% ID after 6 h. Two patients complained of mild gastrointestinal problems and paraesthesia, but no other adverse reactions were observed. SSTR-positive tumours were rapidly visualised as early as 15 min p.i., with maximum tumour uptake (up to 19% ID) and tumour/organ ratios as early as 1 h p.i. Organs of predominant physiological uptake were the spleen and the kidneys, with no intestinal excretion detectable up to 24 h. (99m)Tc-Demotate 1 detected 11 lesions while In-Oct detected ten; differences in uptake behaviour were observed in three patients. This study shows for the first time that peptides derivatised with a tetraamine ligand for labelling with (99m)Tc show suitable properties for receptor imaging in patients. (99m)Tc-Demotate 1 is a promising agent for the visualisation of SSTR-positive lesions in patients, allowing rapid imaging as early as 1 h p.i.; some differences are observed in pharmacokinetic behaviour compared with (111)In-DTPA-octreotide.

Aged↗