INCIDENTAL PARATHYROIDECTOMY DURING TOTAL THYROIDECTOMY AS A POSSIBLE RISK FACTOR OF HYPOCALCEMIA. EXPERIENCE OF A SINGLE CENTER AND REVIEW OF LITERATURE.

CONTEXT: Post-operative clinical and biochemical hypocalcemia is a common complication of thyroid surgery and the correlation with incidental parathyroidectomy (IP) remains controversial. OBJECTIVE: To evaluate the incidence of IP during TT, its correlation to early post-surgery hypocalcemia, and its potential risk factors. PATIENTS AND METHODS: 77 consecutive patients submitted to thyroid surgery between January 2018 and December 2019. Demographic, clinical, biochemical, surgical and histopathological factors were assessed. Statistical multivariate analysis was performed to identify the risk of IP. RESULTS: IP was evident in 22 (28.5%) patients who underwent TT, TT with lymph node dissection of the central compartment (CLND) and reoperation for previous hemithyroidectomy with CLND. Early symptomatic hypocalcemia 24 hours after TT was demonstrated in 12/22 (54.5%) patients, with PTH value of <14pg/mL in 7/12 (58.3%) patients, and in 6 of these 7 patients (85.7%) the PTH value was <6.3pg/mL. In 5/22 (22.7%) patients the IP was associated with biochemical hypocalcemia <8.4mg/dL, and in 5/22 (22.7%) patients anatomical damage was not associated with a reduction in plasma calcium levels. The severity of early post-op hypocalcemia was not correlated with the number of parathyroid glands left in situ. The multivariate analysis did not show statistically significant values between the clinical-pathological variables and increased risk of IP. CONCLUSIONS: No IP clinical-pathological risk factors have been identified during thyroid surgery. In all cases of TT, with or without CLND, the meticulous identification of the parathyroid glands, whose incidental removal is frequently associated with clinical and biochemical hypocalcemia, is recommended.

Multilocus sequence typing of Arcobacter butzleri isolates collected from dairy plants and their products, and comparison with their PFGE types.

AIMS: The present study aimed to determine, by multilocus sequence type (MLST), the heterogeneity level of Arcobacter butzleri isolates and to compare MLST and pulsed-field gel electrophoresis (PFGE) in terms of discriminatory power (DI) as well as unidirectional and bi-directional concordance. METHODS AND RESULTS: Arcobacter butzleri isolates (N = 133) from dairy products and environmental samples, collected from dairy plants, were characterized by MLST and PFGE with SacII and classified in 29 sequence types (STs), 47 PFGE and 62 type strains (TS). Among the 119 alleles, 19 were previously unreported and the same for all the STs but two. A significant linkage disequilibrium was detected when the complete ST data set was analysed The DIs of MLST, PFGE and their combination were 0·937, 0·953 and 0·965 respectively. The adjusted Wallace coefficients between MLST and PFGE as well as PFGE and MLST were 0·535 and 0·720 respectively; the adjusted Rand coefficient was 0·612. CONCLUSIONS: The A. butzleri studied population showed recombination to some degree. PFGE showed a DI higher than MLST. Both methods presented good concordance. The TS analysis seems to show persistence of the same strain on time and possible cross-contaminations between food and environmental sites. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides insights in the A. butzleri population found in raw milk, cheese, and dairy production plants. The data suggest that MLST and PFGE genotypes correlate reasonably well, although their combination results in optimal resolution.

Adenovirus 36 DNA in human adipose tissue.

Recent studies have suggested a possible correlation between obesity and adenovirus 36 (Adv36) infection in humans. As information on adenoviral DNA presence in human adipose tissue are limited, we evaluated the presence of Adv36 DNA in adipose tissue of 21 adult overweight or obese patients. Total DNA was extracted from adipose tissue biopsies. Virus detection was performed using PCR protocols with primers against specific Adv36 fiber protein and the viral oncogenic E4orf1 protein nucleotide sequences. Sequences were aligned with the NCBI database and phylogenetic analyses were carried out with MEGA6 software. Adv36 DNA was found in four samples (19%). This study indicates that some individuals carry Adv36 in the visceral adipose tissue. Further studies are needed to determine the specific effect of Adv36 infection on adipocytes, the prevalence of Adv36 infection and its relationship with obesity in the perspective of developing a vaccine that could potentially prevent or mitigate infection.

Evaluation of E6 and E7 mRNA expression in HPV DNA positive breast cancer.

Several studies have suggested a possible role for HPV in the pathogenesis of the breast cancer. We investigated the presence of the HPV DNA in breast cancers and non malignant disease breast tissues by the use of a standard HPV detection method (INNO-Lipa HPV), in order to detect HPV DNA in metastatic nodes, to investigate a possible cervical HPV co-infection, and to evaluate the E6/E7 mRNA expression in HPV DNA positive breast cancer tissues. The rate of HPV infection was significantly higher in the cancer group than in controls (9/31 vs. 0/12, p = 0.04). One out of eight metastatic axillary nodes was positive for HPV infection; 2/3 of the positive HPV breast cancer patients were co-infected at the cervical site. The role of the virus in breast oncogenesis is still unclear, since our analysis failed in demonstrating the expression of viral E6 and E7 in positive HPV positive breast tumor tissues.

[Hormone replacement therapy after total thyroidectomy. Can the combined treatment be considered effective to get metabolic adequacy? Preliminary results]. / Terapia ormonale sostitutiva dopo tiroidectomia totale. Il trattamento ormonale combinato può essere considerato efficace strumento di adeguatezza metabolica? Risultati preliminari.

INTRODUCTION: Even if T4 is standard treatment for hypothyroidism after thyroidectomy, a treatment with T4 plus T3 has been proposed as an alternative reproducing carefully the physiology of the thyroid. We performed an observational study about the effects of the combined replacement therapy with T4 and T3 in patients who underwent total thyroidectomy. PATIENTS AND METHODS: Fifty thyroidectomized patients (not for cancer), in T4 replacement therapy, were included in the study. Such a therapy has been changed by administering T3 and T4 in proportion 1/16. Adverse effects, clinical parameters and general health perceptions (SF36 Questionnaire) have been considered at the time of enrollment (T0), after 30 days (T1) and after 60 days (T2). RESULTS: No differences in weight, cardiac frequency and blood pression have been found between T0 and T2. A not statistically significant reduction has been found in total cholesterol (3 mg/dL) and triglycerides (3.29 mg/dL) levels. A reduction of complaints referred by the patients at T0 has been revealed in T2: anxiety from 21 to 13 patients; headache from 22 to 13; tiredness from 17 to 8 (p<0.05); sleepiness from 25 to 15 (p<0.05). About the questionnaire, in the General Health Perception sub-score has been found a not significant increase of the parameter. DISCUSSION AND CONCLUSIONS: T4 replacement therapy is of proved efficacy, notwithstanding some complaints afflict a share of patients. To improve the quality of life of these patients, we consider relevant the reduction of complaints and the improvement of well-being and cognitive function obtained by the combined T4 and T3 treatment. Moreover, even if the production of T3 from T4 usually ensures euthyroidism in all tissues, contemporary pathologies and alterations determined by the oldness can disturb the enzymatic activity, which is the essential requirement of T4 therapy. These preliminary findings in a small group of patients encourage further studies on a larger patient population.

Clostridium perfringens occurrence and ribotypes in healthy broilers reared in different European countries.

The main aim of this study was to investigate the occurrence and ribotypes of Clostridium perfringens in broiler flocks reared in 2 European countries that apply European Union Regulation 1831/2003. A total of 1,532 cecum contents were collected between June 2005 and November 2006 from birds belonging to 51 intensively reared flocks produced in the Czech Republic and 41 intensive production, organic, and free-range flocks reared in Italy. Clostridium perfringens was detected in 64.7 and 82.9% of the Czech Republic and Italian flocks, respectively, at mean loads ranging between 3.65 and 4.77 log10 cfu per gram of cecum content. More than 1 ribotype was identified among isolates belonging to the same flock in 57.1 and 76.5% of the Czech Republic and Italian flocks, respectively. Moreover, common ribotypes were identified between strains belonging to 2 up to 8 different flocks. In particular, 4 ribotypes were shared between strains isolated in the 2 European countries. The results of this study report on C. perfringens occurrence and mean populations in broilers reared on diets devoid of antibiotic growth promoters. Moreover, these findings show for the first time the presence of common ribotyping profiles among isolates collected from birds reared more than 1,000 km apart.

Application of different DNA extraction procedures, library preparation protocols and sequencing platforms: impact on sequencing results.

In this study three DNA extraction procedures, two library preparation protocols and two sequencing platforms were applied to analyse six bacterial cultures and their corresponding DNA obtained as part of a proficiency test. The impact of each variable on sequencing results was assessed using the following parameters: reads quality, assembly and alignment statistics; number of single nucleotide polymorphisms (SNPs), detected applying assembly- and alignment-based strategies; antimicrobial resistance genes (ARGs), identified on de novo assemblies of all sequenced genomes. The investigated nucleic acid extraction procedures, library preparation kits and sequencing platforms do not significantly affect de novo assembly statistics and number of SNPs and ARGs. The only exception was observed for two duplicates, which were associated to one PCR-based library preparation kit. Results from this comparative study can support researchers in the choice toward the available pre-sequencing and sequencing options, and might suggest further comparisons to be performed.

Total thyroidectomy associated to chemotherapy in primary squamous cell carcinoma of the thyroid.

Primary squamous cell carcinoma of the thyroid (PSCCT) is a rare malignant disease with rapid fatal prognosis. The onset is generally characterized by sudden bilateral latero-cervical lymphadenopathy. The Authors report patient of 58-year-old who referred for evaluation of rapidly aggravating bilateral latero-cervical lymphadenopathy. The US highlighted the presence of a hypoechoic nodular lesion characterized by peri and intra-nodular vascularization. Multilayer CT showed diffused involvement of mediastinal and bilateral latero-cervical lymph nodes, with no evidence of primary pulmonary neoplasia or elsewhere. The patient underwent total thyroidectomy. The peri-isthmic tissue was removed due to the presence of a small roundish formation, that was due to lymph node metastasis at histological examination. Histological diagnosis: PSCCT. The immunohistochemical panel of the thyroid lesion was indispensable for the differential diagnosis between PSCCT, medullary carcinoma, anaplastic carcinoma, and thyroid metastasis of neoplasia with unknown primitiveness. The patient underwent chemotherapeutic treatment with Carboplatin and Paclitaxel with modest improvement of dysphagia symptoms and reduction of 10-15% of the target lesions. The clinical course was characterized by loco-regional progression of the disease with exitus in 10 months after diagnosis. Survival and quality of life after surgical therapy and chemotherapy were like that of patients undergoing only chemotherapy. Due to the extreme rarity of the neoplasia, 60 cases described in Literature, no exclusive guidelines are reported for PSCCT. More extensive case studies are needed to evaluate the effects of total thyroidectomy with intent R0/R1 on improving survival and quality of life of patients with PSCCT.

Genotypic and phenotypic diversity within three Campylobacter populations isolated from broiler ceca and carcasses.

The main aim of this study was to trace Campylobacter subtypes colonizing Italian broilers and carcasses in and between flocks. Overall, 209 Campylobacter isolates were collected from ceca (n = 94) and carcasses (n = 115) of broilers belonging to 3 different flocks reared in the same farm during subsequent rotations and processed in the same slaughterhouse. All isolates were identified by multiplex polymerase chain reaction and genotyped by amplified fragment length polymorphism. Furthermore, 166 out of 209 strains were phenotyped by antimicrobial resistance profile (R-type). The results of genetic and phenotypic characterization showed that (1) multiple Campylobacter species and subtypes can colonize the same broiler and carcass; (2) common Campylobacter subtypes in ceca and carcasses seem to be rare; and (3) carryover of Campylobacter subtypes between broiler flocks in the same house rarely occurs. The outcomes of this study should be taken into account for setting of isolate collection during epidemiological investigations to check sources and transmission routs of Campylobacter in broilers and poultry products.

Application of automated ribotyping to support the evaluation of Listeria monocytogenes sources in a Taleggio cheese producing plant.

In March 2005, Listeria monocytogenes was detected on the rinds of Taleggio cheeses produced in an Italian plant. To identify the pathogen source, 154 rinds of cheeses that had been manually and automatically salinated and 52 environmental swabs collected from salting equipment, ripening cloths, and ripening boxes were tested for L. monocytogenes. Twenty-seven strains isolated from cheese samples and 16 strains isolated from environmental samples were genotyped by EcoRI and PvuII automated ribotyping. The microbiological results revealed a significant incidence of contamination of cheeses that were automatically salinated and contamination on the salting equipment, ripening cloths, and boxes. All cheese and environmental strains had the same EcoRI and PvuII ribotyping profiles, designated 153-204-S5 and 153-210-S-2, respectively. The only exception were three Taleggio strains, isolated from the same lot of product, that had EcoRI and PvuII ribotyping profiles designated 153-289-S6 and 153-214-S-5, respectively. Strains with EcoRI profile 153-204-S5 were classified as DUP-ID 1045 and serotype 1/2a, whereas strains with EcoRI profile 153-289-S6 were classified as DUP-ID 1034 and serotype 1/2b. The microbiological and molecular typing data collected in this study suggest that the source of the L. monocytogenes contamination in the Taleggio plant under study was the automated salting equipment. The isolate DUP-IDs were used to trace the introduction of potentially dangerous strains, such as those characterized as DUP-ID 1034, in the processing plant.

Risk of mortality from cardiovascular and respiratory causes in patients with chronic obstructive pulmonary disease submitted to follow-up after lung resection for non-small cell lung cancer.

AIM: Considerable controversy surrounds mortality from non-neoplastic diseases during the postoperative follow-up of patients with non-small cell lung cancer (NSCLC) and chronic obstructive pulmonary disease (COPD). This study investigated the incidence of mortality from cardiovascular and respiratory (CVR) causes in patients with COPD submitted to follow-up after lung resection for NSCLC, and identified preoperative and postoperative risk factors. METHODS: A total of 398 patients with mild or moderate COPD were followed up in our department after lung resection for NSCLC (median follow-up 61 months). Statistical analysis of the data was carried out to determine the incidence and the prognostic factors of postoperative death from CVR causes. RESULTS: Of the 398 resected patients, 186 survived without tumor recurrence; 24/186 (12.9%) died of CVR causes (acute respiratory failure, pneumonia, pulmonary embolism, acute pulmonary edema, acute myocardial ischemia or stroke). These 24 patients had a higher frequency of pre-existing coronary artery disease or heart failure (P=0.0003), predicted postoperative FEV1 <1000 mL (P=0.0008), exertional dyspnea (P=0.0000), and 30-day operative cardiopulmonary complications (P=0.001). Protective features were young age (<40 years), early stage disease, and minor resection (lobectomy). Independently significant adverse prognostic factors were stage III-IV disease (cumulative CVR death rate 47% at 5-10 years; P=0.028 vs. stage I-II) and completion pneumonectomy or partial resection of the other lung for a second primary tumor (cumulative CVR death rate 50% and 57%, respectively, at 5-10 years; P=0.0016 vs. all other resections). Older age and tumor histology were significant risk factors only in patients with advanced stage disease. CONCLUSION: The findings suggest that postoperative CVR death may be expected in patients with COPD and advanced stage NSCLC or in those undergoing completion pneumonectomy or partial resection of the other lung for a second primary tumor. Other risk factors are previous coronary artery disease and/or heart failure, exertional dyspnea and predicted postoperative FEV1 <1000 mL.

[Tissue attenuation in small animals on contrast enhanced ultrasound]. / Prise en compte de l'atténuation ultrasonore en présence d'agents de contraste chez le petit animal.

Despite recent advances in contrast-enhanced ultrasound imaging, evaluation of tissue perfusion with contrast-enhanced ultrasound is still impaired by shadowing effects. These effects are particularly relevant in small animal studies due to high frequency imaging. Current methods of tissue attenuation correction are not suited for contrast-enhanced ultrasound examinations, because microbubble acoustic response to ultrasound waves is far more complex than that of tissues. A method allowing in vivo tissue attenuation correction in the presence of contrast agents is presented.

Bilateral hydrocele. Uncommon clinical presentation of primary testicular lymphoma in the elderly.

Primary testicular lymphoma (PLT) represents 5% of testis tumors, the incidence increases in patients older than 60 years of age. Bilateral hydrocele is an unusual clinical presentation. Relapse in the central nervous system and in the contralateral testis is often observed. The US shows hypoechoic nodular lesions with a complete structural involvement of didymus and hypervascularization at Color Doppler. Orchiectomy should be performed in all cases as it is indispensable for the histopathological diagnosis and to characterize the immunophenotypic features. The most common histotype is diffuse large-B cell lymphoma. Combined biological approach and chemotherapy with rituximab and doxorubicin has radically changed the prognosis of disease. The authors report two patients of 81 and 82 years-old who referred for evaluation of massive bilateral hydrocele causing severe limitation of deambulation. Negative cytological findings for neoplastic cells in the scrotal effusion made difficult the differential diagnosis between inflammatory and malignant disease. Histopathologic findings made a diagnosis of high grade diffuse large B-cell NHL, respectively stage IV-E and stage III-E. The 82 years old patient was treated with 6 chemotherapy cycles of rituximab, cyclophosphamide, vincristine, prednisone. The exitus was dued to the umbilical hernia complications. In the 81 years old patient, cognitive deficit and severe impairment of general conditions constituted an absolute contraindication to polychemotherapy treatment. Rapid tumor progression led the patient to exitus 2 months after diagnosis. In both patients the delayed diagnosis of PLT was probably due to the reduction of welfare protection in the elderly with adverse social conditions.

Enumeration and identity of Campylobacter spp. in Italian broilers.

Transmission of Campylobacter to humans has been prominently associated with mishandling or improperly preparing contaminated poultry carcasses. The number of organisms per carcass represents an important measure of human exposure to the agent. Therefore, we wished to estimate this public exposure over 1 yr among Italian broiler carcasses. We sampled 213 broiler carcasses from rinse water samples collected from a single slaughterhouse. Groups of carcasses had mean processed weights ranging from 1.2 to 2.7 kg. These were produced from 22 commercial broiler chicken flocks collected from 12 different farms, 3 of which were seasonally tested. Carcasses were rinsed with sterile water, and the rinse suspension was then serially diluted and spread-plated directly onto Campy-Cefex agar plates. One to 5 typical Campylobacter colonies per plate were identified by polymerase chain reaction as Campylobacter thermo-tolerant species. The overall estimated mean count per carcass in our study was 5.16 +/- 0.80 log10 cfu. This value increased in summer and autumn, as well as on carcasses collected from farms located > 100 km far from the slaughterhouse. A total of 678 Campylobacter colonies were identified by polymerase chain reaction. The majority of isolates were classified as Campylobacter jejuni (49.2%) or Campylobacter coli (47.5%). The overall number of C. jejuni was significantly higher on 1) carcasses weighing > 2 kg, 2) carcasses belonging to flocks with > 10,000 birds, and 3) carcasses collected from farms located > 100 km from the slaughterhouse. Moreover, among farms tested seasonally, C. jejuni was significantly greater than C. coli in winter. These data provide the first results of a continuing survey on Campylobacter loads and species identification from Italian broiler carcasses and represents an important baseline to estimate the human exposure to Campylobacter in Italy.

Assessment of left ventricular contraction by parametric analysis of main motion (PAMM): theory and application for echocardiography.

The computerized study of the regional contraction of the left ventricle has undergone numerous developments, particularly in relation to echocardiography. A new method, parametric analysis of main motion (PAMM), is proposed in order to synthesize the information contained in a cine loop of images in parametric images. PAMM determines, for the intensity variation time curves (IVTC) observed in each pixel, two amplitude coefficients characterizing the continuous component and the alternating component; the variable component is generated from a mother curve by introducing a time shift coefficient and a scale coefficient. Two approaches, a PAMM data driven and a PAMM model driven (simpler and faster), are proposed. On the basis of the four coefficients, an amplitude image and an image of mean contraction time are synthesized and interpreted by a cardiologist. In all cases, both PAMM methods allow better IVTC adjustment than the other methods of parametric imaging used in echocardiography. A preliminary database comprising 70 segments is scored and compared with the visual analysis, taken from a consensus of two expert interpreters. The levels of absolute and relative concordance are 79% and 97%. PAMM model driven is a promising method for the rapid detection of abnormalities in left ventricle contraction.

A reduced calorie-high fiber diet retards age-associated decreases in muscarinic receptor sensitivity.

The effects of a reduced calorie-high fiber diet (RCHF) were examined on three cholinergic signal transduction (ST) parameters: (a) oxotremorine enhancement of K(+)-evoked dopamine release and (b) carbachol-stimulated low KM GTPase activity [an indicator of muscarinic receptor (mAChR)-G protein coupling/uncoupling], and (c) [3H]Quinuclidinyl benzilate (QNB) autoradiography. Comparisons were made among: young control (6 months), old normal control, old reduced calorie high fiber [both 24 months)]. The results indicated that old reduced calorie high fiber rats (1900 kcal/kg/day, 2.4%, lipids 2.4%, fiber 28%, carbohydrates 40.7%) as compared to the old normal control rats (3000 kcal/kg/day, 4.8% lipids, 4.2% fiber, carbohydrates 61.5%) showed a retardation of age-related deficits in dopamine release (a above) and GTPase activity (b above). These parameters were 25% higher in the old reduced calorie high fiber rats as compared to old normal controls and did not differ from young controls, even though there was no increase in mAChR concentration in the restricted group. Thus, these results indicate that a reduced calorie high fiber diet as utilized in these experiments was effective in retarding the age-related decrements in two of three signal transduction parameters. They are discussed in terms of the induction of membrane changes (e.g., fluidity) or related decreases in oxidative stress by the restricted diet that may be involved in these signal transduction effects.

Validation of myocardial perfusion reserve measurements using regularized factor images of H(2)(15)O dynamic PET scans.

UNLABELLED: The use of H(2)(15)O PET scans for the measurement of myocardial perfusion reserve (MPR) has been validated in both animal models and humans. Nevertheless, this protocol requires cumbersome acquisitions such as C(15)O inhalation or (18)F-FDG injection to obtain images suitable for determining myocardial regions of interest. Regularized factor analysis is an alternative method proposed to define myocardial contours directly from H(2)(15)O studies without any C(15)O or FDG scan. The study validates this method by comparing the MPR obtained by the regularized factor analysis with the coronary flow reserve (CFR) obtained by intracoronary Doppler as well as with the MPR obtained by an FDG acquisition. METHODS: Ten healthy volunteers and 10 patients with ischemic cardiopathy or idiopathic dilated cardiomyopathy were investigated. The CFR of patients was measured sonographically using a Doppler catheter tip placed into the proximal left anterior descending artery. The mean velocity was recorded at baseline and after dipyridamole administration. All subjects underwent PET imaging, including 2 H(2)(15)O myocardial perfusion studies at baseline and after dipyridamole infusion, followed by an FDG acquisition. Dynamic H(2)(15)O scans were processed by regularized factor analysis. Left ventricular cavity and anteroseptal myocardial regions of interest were drawn independently on regularized factor images and on FDG images. Myocardial blood flow (MBF) and MPR were estimated by fitting the H(2)(15)O time-activity curves with a compartmental model. RESULTS: In patients, no significant difference was observed among the 3 methods of measurement-Doppler CFR, 1.73 +/- 0.57; regularized factor analysis MPR, 1.71 +/- 0.68; FDG MPR, 1.83 +/- 0.49-using a Friedman 2-way ANOVA by ranks. MPR measured with the regularized factor images correlated significantly with CFR (y = 1.17x - 0.30; r = 0.97). In the global population, the regularized factor analysis MPR and FDG MPR correlated strongly (y = 0.99x; r = 0.93). Interoperator repeatability on regularized factor images was 0.126 mL/min/g for rest MBF, 0.38 mL/min/g for stress MBF, and 0.34 for MPR (19% of mean MPR). CONCLUSION: Regularized factor analysis provides well-defined myocardial images from H(2)(15)O dynamic scans, permitting an accurate and simple measurement of MPR. The method reduces exposure to radiation and examination time and lowers the cost of MPR protocols using a PET scanner.

Isolated intestinal neurofibromatosis of colon. Single case report and review of the literature.

Isolated intestinal neurofibromatosis of the colon is a most unusual disease: from 1937 to 1999 only 12 cases have been reported. The differential diagnosis and treatment of this lesion are very difficult. A review of the literature is made and personal experience in the diagnosis and treatment of a case in a 68-year-old female is described.

Spatial regularization applied to factor analysis of medical image sequences (FAMIS).

Dynamic image sequences allow physiological mechanisms to be monitored after the injection of a tracer. Factor analysis of medical image sequences (FAMIS) hence creates a synthesis of the information in one image sequence. It estimates a limited number of structures (factor images) assuming that the tracer kinetics (factors) are similar at each point inside the structure. A spatial regularization method for computing factor images (REG-FAMIS) is proposed to remove irregularities due to noise in the original data while preserving discontinuities between structures. REG-FAMIS has been applied to two sets of simulations: (a) dynamic data with Gaussian noise and (b) dynamic studies in emission tomography (PET or SPECT), which respect real tomographic acquisition parameters and noise characteristics. Optimal regularization parameters are estimated in order to minimize the distance between reference images and regularized factor images. Compared with conventional factor images, the root mean square error between regularized images and reference factor images is improved by 3 for the first set of simulations, and by about 1.5 for the second set of simulations. In all cases, regularized factor images are qualitatively and quantitatively improved.