Utility of artificial intelligence for detection of pneumothorax on chest radiopgraphs done after transthoracic percutaneous transthoracic biopsy guided by computed tomography.

OBJETIVE: To assess the ability of an artificial intelligence software to detect pneumothorax in chest radiographs done after percutaneous transthoracic biopsy. MATERIAL AND METHODS: We included retrospectively in our study adult patients who underwent CT-guided percutaneous transthoracic biopsies from lung, pleural or mediastinal lesions from June 2019 to June 2020, and who had a follow-up chest radiograph after the procedure. These chest radiographs were read to search the presence of pneumothorax independently by an expert thoracic radiologist and a radiodiagnosis resident, whose unified lecture was defined as the gold standard, and the result of each radiograph after interpretation by the artificial intelligence software was documented for posterior comparison with the gold standard. RESULTS: A total of 284 chest radiographs were included in the study and the incidence of pneumothorax was 14.4%. There were no discrepancies between the two readers' interpretation of any of the postbiopsy chest radiographs. The artificial intelligence software was able to detect 41/41 of the present pneumothorax, implying a sensitivity of 100% and a negative predictive value of 100%, with a specificity of 79.4% and a positive predictive value of 45%. The accuracy was 82.4%, indicating that there is a high probability that an individual will be adequately classified by the software. It has also been documented that the presence of Port-a-cath is the cause of 8 of the 50 of false positives by the software. CONCLUSIONS: The software has detected 100% of cases of pneumothorax in the postbiopsy chest radiographs. A potential use of this software could be as a prioritisation tool, allowing radiologists not to read immediately (or even not to read) chest radiographs classified as non-pathological by the software, with the confidence that there are no pathological cases.

In vitro models for neuropathic pain phenotypic screening in brain therapeutics.

The discovery of brain therapeutics faces a significant challenge due to the low translatability of preclinical results into clinical success. To address this gap, several efforts have been made to obtain more translatable neuronal models for phenotypic screening. These models allow the selection of active compounds without predetermined knowledge of drug targets. In this review, we present an overview of various existing models within the field, examining their strengths and limitations, particularly in the context of neuropathic pain research. We illustrate the usefulness of these models through a comparative review in three crucial areas: i) the development of novel phenotypic screening strategies specifically for neuropathic pain, ii) the validation of the models for both primary and secondary screening assays, and iii) the use of the models in target deconvolution processes.

Splicing accuracy varies across human introns, tissues and age.

Alternative splicing impacts most multi-exonic human genes. Inaccuracies during this process may have an important role in ageing and disease. Here, we investigated mis-splicing using RNA-sequencing data from ~14K control samples and 42 human body sites, focusing on split reads partially mapping to known transcripts in annotation. We show that mis-splicing occurs at different rates across introns and tissues and that these splicing inaccuracies are primarily affected by the abundance of core components of the spliceosome assembly and its regulators. Using publicly available data on short-hairpin RNA-knockdowns of numerous spliceosomal components and related regulators, we found support for the importance of RNA-binding proteins in mis-splicing. We also demonstrated that age is positively correlated with mis-splicing, and it affects genes implicated in neurodegenerative diseases. This in-depth characterisation of mis-splicing can have important implications for our understanding of the role of splicing inaccuracies in human disease and the interpretation of long-read RNA-sequencing data.

Identification of differentially expressed genes profiles in a combined mouse model of Parkinsonism and colitis.

Different cellular mechanisms have been described as being potentially involved in the progression of neurodegeneration in Parkinson's disease, although their role is still unclear. The present study aimed to identify in detail, through differentially expressed genes analysis by bioinformatics approaches, the molecular mechanisms triggered after a systemic insult in parkinsonian mice. To address this objective, we combined a dextran sodium sulfate (DSS)-induced ulcerative colitis experimental mice model with an acute 1-methyl-4-phenyl-1,2,3,6-tetradropyridine (MPTP) intoxication. The animals were divided into four experimental groups based on the different treatments: (i) control, (ii) DSS, (iii) MPTP and (iv) MPTP + DSS. The data obtained by microarray and functional enrichment analysis point out the implication of different molecular mechanisms depending on the experimental condition. We see, in the striatum of animals intoxicated only with DSS, dysfunction processes related to the blood. On the other hand, oxidative stress processes are more prominent at the MPTP intoxicated mice. Finally, differentially expressed genes within the MPTP + DSS show functional enrichment in inflammation and programmed cell death. Interestingly, we identify a significant synergistic negative effect of both toxins since the expression of differentially expressed genes (DEGs) related to balanced cellular homeostasis was not enough to prevent processes associated with cell death. This work provides detailed insights into the involvement of systemic inflammation, triggered after an insult in the colon, in the progression of the degeneration in Parkinsonism. In this way, we will be able to identify promising therapeutic targets that prevent the contribution of inflammatory processes in the progression of Parkinson's disease.

Essential role of the C148-C227 disulphide bridge in the human 5-HT2A homodimeric receptor.

The 5-HT2A receptor is a homodimeric G protein-coupled receptor implied in multiple diseases, including schizophrenia. Recently, its co-crystallisation with the antipsychotic drugs zotepine and risperidone has revealed the importance of its extracellular domains in its pharmacology. Previous studies have shown that the non-specific disruption of extracellular disulphide bridges in the 5-HT2A receptor decreases ligand binding and receptor activation. There is enough evidence to hypothesize that this decrease may be due to a reduction of the disulphide bridge that links transmembrane domain 3 (TM-3) and extracellular loop 2 (ECL-2) of the 5-HT2A receptor via cysteine 148 (C148) and C227. Thus, to study the influence of the C148-C227 disulphide bridge on 5-HT2A receptor pharmacology, we substituted C148 and C227 in the human 5-HT2A receptor (WT) with alanines, to obtain two single mutants (C148A and C227A) and a double mutant (C148A/C227A), and the resultant DNA constructs were used to generate four stable cell lines. These substitutions reduced the binding of the 5-HT2A receptor to [3H]lysergic acid diethylamide ([3H]LSD) and impeded the 5-HT2A receptor-mediated activation of phospholipase C (PLC). Furthermore, bioluminescence resonance energy transfer (BRET) and western blotting analysis revealed that these mutations did not alter the homodimeric nature of the 5-HT2A receptor. However, fluorescence microscopy showed that these mutations hindered receptor trafficking to the cell membrane. These results illustrate the importance of the disulphide bridge between TM-3 and ECL-2 in maintaining the correct 5-HT2A receptor conformation to allow ligand binding and migration of the homodimeric receptor to the cell membrane.

Parkinson's disease: a short story of 200 years.

After Alzheimer's disease, Parkinson's disease (PD) is the second most prevalent and incidental neurodegenerative disorder, affecting more than 2% of the population older than 65 years old. Since it was first described 200 years ago by Dr James Parkinson, great steps have been made in the understanding of the pathology. However, the cause(s) that initiates and perpetuates the neurodegenerative process is (are) still not clear. Thus, early diagnosis is not available, nor are there efficient therapies that can stop neurodegeneration. PD clinical features are defined by motor (like bradykinesia, resting tremor, gait impairment) and non-motor symptoms (like constipation, apathy, fathigue, olfactory dysfunction, depression and cognitive decline) that get more severe as the disease advances. Neuropathological hallmarks comprise selective loss of dopaminergic neurons in the Substantia Nigra pars compacta (SNpc) and Lewy bodies (LB) in different nuclei of the nervous system. Numerous studies have shown that these pathological features are aggravated by the confluence of other contributing factors, such as a genetic component, exposure to environmental toxins, mitochondrial dysfunction, increase of oxidative stress, calcium imbalance and chronic neuroinflammation, among others. Here, we provide a summary of the actual state of PD's pathology, the most studied molecular mechanisms, classic and novel therapeutic strategies and diagnosis methods, especially highlighting recent advances in these 200 years.

Electrical stimulation or MK-801 in the inferior colliculus improve motor deficits in MPTP-treated mice.

The inferior colliculus (IC) is an important midbrain relay station for the integration of descending and ascending auditory information. Additionally, the IC has been implicated in processing sensorimotor responses. Glutamatergic and GABAergic manipulations in the IC can improve motor deficits as demonstrated by the animal model of haloperidol-induced catalepsy. However, how the IC influences motor function remains unclear. We investigated the effects of either intracollicular deep brain stimulation (DBS) or microinjection of the glutamatergic antagonist MK-801 or the agonist NMDA in C57BL/6J mice chronically treated with saline or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). After DBS or microinjections, the mice were submitted to rotarod and open field tests, respectively. DBS in the IC was effective to increase the time spent on the rotarod in MPTP-treated mice. After unilateral microinjection of MK-801, but not NMDA, MPTP-treated mice increased the distance travelled in the open field (p < 0.05). In conclusion, intracollicular DBS or MK-801 microinjection can improve motor performance in parkinsonian mice suggesting the IC as a new and non-conventional therapeutic target in motor impairment.

Alteration of the PAC1 Receptor Expression in the Basal Ganglia of MPTP-Induced Parkinsonian Macaque Monkeys.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a well-known neuropeptide with strong neurotrophic and neuroprotective effects. PACAP exerts its protective actions via three G protein-coupled receptors: the specific Pac1 receptor (Pac1R) and the Vpac1/Vpac2 receptors, the neuroprotective effects being mainly mediated by the Pac1R. The protective role of PACAP in models of Parkinson's disease and other neurodegenerative diseases is now well-established in both in vitro and in vivo studies. PACAP and its receptors occur in the mammalian brain, including regions associated with Parkinson's disease. PACAP receptor upregulation or downregulation has been reported in several injury models or human diseases, but no data are available on alterations of receptor expression in Parkinson's disease. The model closest to the human disease is the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced macaque model. Therefore, our present aim was to evaluate changes in Pac1R expression in basal ganglia related to Parkinson's disease in a macaque model. Monkeys were rendered parkinsonian with MPTP, and striatum, pallidum, and cortex were evaluated for Pac1R immunostaining. We found that Pac1R immunosignal was markedly reduced in the caudate nucleus, putamen, and internal and external parts of the globus pallidus, while the immunoreactivity remained unchanged in the cortex of MPTP-treated parkinsonian monkey brains. This decrease was attenuated in some brain areas in monkeys treated with L-DOPA. The strong, specific decrease of the PACAP receptor immunosignal in the basal ganglia of parkinsonian macaque monkey brains suggests that the PACAP/Pac1R system may play an important role in the development/progression of the disease.

Variability among Capsicum baccatum accessions from Goiás, Brazil, assessed by morphological traits and molecular markers.

Capsicum peppers are native to the Americas, with Brazil being a significant diversity center. Capsicum baccatum accessions at Instituto Federal (IF) Goiano represent a portion of the species genetic resources from central Brazil. We aimed to characterize a C. baccatum working collection comprising 27 accessions and 3 commercial cultivars using morphological traits and molecular markers to describe its genetic and morphological variability and verify the occurrence of duplicates. This set included 1 C. baccatum var. praetermissum and 29 C. baccatum var. pendulum with potential for use in breeding programs. Twenty-two morphological descriptors, 57 inter-simple sequence repeat, and 34 random amplified polymorphic DNA markers were used. Genetic distance was calculated through the Jaccard similarity index and genetic variability through cluster analysis using the unweighted pair group method with arithmetic mean, resulting in dendrograms for both morphological analysis and molecular analysis. Genetic variability was found among C. baccatum var. pendulum accessions, and the distinction between the two C. baccatum varieties was evident in both the morphological and molecular analyses. The 29 C. baccatum var. pendulum genotypes clustered in four groups according to fruit type in the morphological analysis. They formed seven groups in the molecular analysis, without a clear correspondence with morphology. No duplicates were found. The results describe the genetic and morphological variability, provide a detailed characterization of genotypes, and discard the possibility of duplicates within the IF Goiano C. baccatum L. collection. This study will foment the use of this germplasm collection in C. baccatum breeding programs.

Neurotrophic keratitis after transscleral diode laser cyclophotocoagulation. / Queratitis neurotrófica posciclofotocoagulación transescleral con láser diodo.

OBJECTIVE: To study the relationship between treatment with diode laser transscleral cyclophotocoagulation and development a neurotrophic keratitis due to the damage of the sensitive corneal innervation. METHODS: A study was conducted on 5 eyes of 5 patients who were treated with diode laser transscleral cyclophotocoagulation and soon developed neurotrophic ulcers. Personal characteristics of the patients were collected, as well as refraction and risk factors for corneal hypoesthesia, and the parameters of the laser used in the surgery. RESULTS: It was found that the 5 patients had predisposing factors of corneal hypoesthesia prior to surgery (chronic use of topical beta blockers, surgery with corneal incisions, diabetes mellitus, or corneal dystrophies); however none had developed neurotrophic keratitis until the cyclophotocoagulation was performed. It also showed that 4 of them were highly myopic, and they all were treated with high laser parameters (with an average of 2880 mW for 3s at an average surface of 275°), triggering neurotrophic ulcers between 10 and 35 days after surgery. CONCLUSION: Neurotrophic keratitis is a rare complication that can occur after diode laser transscleral cyclophotocoagulation, secondary to the damage of the long ciliary nerves. The emergence of this disorder can be triggered by the existence of previous risk factors, including high myopia, thus it is important to respect the recommended treatment parameters to prevent the development of this disorder.

Effect of feeding system and breed on growth performance, and carcass and meat quality traits in two continental beef breeds.

A total of 100 young bulls were allotted a 2 × 2 factorial arrangement of treatments to determine the effect of the feeding system (concentrate and wheat straw: T; total mixed ration comprised of the same concentrate, maize silage and wheat straw: TMR) and breed (Limousine: LI; Retinta: RE) on growth performance, carcass characteristics and meat quality. The diets were administrated ad libitum for 193 days. The average daily weight gain was similar (P > 0.05) for both diets, while the LI bulls grew significantly (P < 0.05) more than RE. T bulls showed higher L*, a* and rib bone percentage. TMR bulls showed higher carcass yield, conformation and fatness, and greater changes in ultrasound measurements, except Δ UGMD and rib fat percentage. Instrumental meat quality, except shear force at 1 and 21 days of ageing, was not affected (P > 0.05) by the diets. Breed significantly affected most of the analyzed characteristics.

Associations between DGAT1, FABP4, LEP, RORC, and SCD1 gene polymorphisms and fat deposition in Spanish commercial beef.

The objective of the present study was to assess the frequency distribution of markers in the diacylglycerol acyltransferase (DGAT1), fatty acid binding protein 4 (FABP4), leptin (LEP), retinoic acid receptor-related orphan receptor C (RORC), and stearoyl-CoA desaturase (SCD1) genes in a Spanish commercial crossbred population (n = 286) produced in southwest Spain. We have also evaluated the association of these 5 major SNP with backfat thickness (BFT) and intramuscular fat (IMF) to use them routinely in the industry (if the associations are confirmed) due to their ease of use. The KK genotype of the DGAT1 gene was associated (P = 0.046) with the greatest BFT value. Bulls presenting the GG genotype for SNP in the FABP4 gene showed greater values for the percentage of IMF (P = 0.030), which means an increase of 0.155% IMF per copy of the G allele of this marker (P = 0.009). A significant association was found between the RORC: g.3290T > G marker and the percentage of IMF. The GG genotype of the RORC: g.3290T > G marker showed the lowest IMF percentage (P = 0.025). The specific associations found in this study not only provide information about the involvement of these genes in the fat deposition at different levels in the southwestern Spain cattle population, but can also serve as a tool to improve certain meat quality attributes through Marker Assisted Selection. However, sensory studies are needed to explore further the usefulness of these genes in meat quality and the impact on the actual palatability of the beef.

Sedative and anxiolytic efficacy of Tilia americana var. mexicana inflorescences used traditionally by communities of State of Michoacan, Mexico.

AIM OF THE STUDY: Increasing demand of herbal products acquired in stores and markets, as well as medicinal plants collected for personal consume are a known modern tendency. In this study, the ethnomedicinal use of Tilia americana var. mexicana inflorescences as sedative and anxiolytic is reinforced by examinating inflorescences used by communities of the State of Michoacan, Mexico. MATERIALS AND METHODS: Experimental mouse models were used to evaluate the sodium pentobarbital (SP)-induced hypnosis potentiation, ambulatory activity, as well as sedative and anti-anxiety responses via oral administration of the aqueous extracts (10, 30 and/or 100 and 300mg/kg). RESULTS: All samples tested produced a lengthening in the time of SP. Moreover, a significant attenuation in the anxiety-response in the plus-maze test and a diminution in both the head dipping response and ambulatory activity were observed resembling the response to diazepam (0.3mg/kg, i.p.). TLC profiles of the samples showed similar pattern of flavonoids; HPLC-DAD exhibited peaks identified as derived of quercetin and kaempferol that may be responsible for the plant activity. CONCLUSIONS: Our results demonstrate that inflorescences of stored specimens obtained from popular local markets show the same effectiveness with regard to sedative and anxiolytic-like actions than freshly collected samples. Since no toxicity was observed through this route of administration (up to 5000mg/kg); therefore, it suggests that this plant is secure when used as tranquilizer in folk medicine.

Evaluation of the antinociceptive effect of Rosmarinus officinalis L. using three different experimental models in rodents.

The rationale of this investigation was to examine the antinociceptive effect of an ethanol extract of Rosmarinus officinalis (RO) aerial parts, using three different experimental models: acetic acid-induced writhing test and formalin test in mice; and a model of arthritic pain: "pain-induced functional impairment model in the rat (PIFIR model)". The antinociceptive efficacies were evaluated using several dose-response curves and time courses. The antinociceptive effects from RO extract were compared with the antinociceptive effect of either tramadol (TR: 3.16-50 mg/kg, i.p. in mice, and 1.0-31.62 mg/kg, i.p. in rats) or acetylsalicylic acid (AA: 31.62-562.32 mg/kg, p.o.). RO extract (10-300 mg/kg, p.o.) significantly (P < 0.001) reduced the number of writhing movement induced by the i.p. administration of acetic acid solution in a dose-dependent way (ED50 = 108.84 mg/kg, whereas, TR showed an ED50 = 12.38 mg/kg). In addition, RO extract (30-300 mg/kg) significantly (P < 0.001) inhibited licking and shaking behaviours in both early (neurogenic pain) and in the late (inflammatory pain) phases of the formalin test. These effects were like those produced by TR. Concerning the results using the PIFIR model, RO extract (30-3000 mg/kg, p.o.) like either TR or AA, produced a significant (P < 0.001) and dose-dependent antinociceptive response in rats (RO: ED50 = 222.78 mg/kg versus TR: ED50 = 11.06 mg/kg and AA: ED50 = 206.13 mg/kg). These results strongly suggest that aerial parts of RO possess antinociceptive and anti-inflammatory activity, and reinforce the use of this plant in folk medicine.

Pharmacological evaluation of the anxiolytic and sedative effects of Tilia americana L. var. mexicana in mice.

The anxiolytic and sedative effects of Tilia americana L. var. mexicana (Schltdl.) Hardin inflorescence extracts and its acute toxicity were tested. Sodium pentobarbital (SP)-induced hypnosis potentiation (SPP), as well as ambulatory activity and anti-anxiety response in three different experimental models were evaluated with hexane and methanol extracts in mice. In order to determine the proper timing of assessments and to identify the most active extract, a 100mg/kg dosage of hexane, ethyl acetate and methanol crude extracts were tested on SPP after 15, 30 and 60min of the administration. Then a dose-response curve was made for the hexane (10-1000mg/kg) and methanol (10-300mg/kg) extracts in all experimental models. Both extracts produced a significant and dose-dependent lengthening in the time of SP, with the methanol extract being more potent than the hexane extract at 60min after administration. Moreover, a significant and dose-dependent attenuation in the anxiety-response in the plus-maze test and exploratory cylinder activity, but also a diminution in the ambulatory activity and in the head dipping response were observed resembling the response to diazepam. Acute toxicity was observed with less dose of methanol extract (LD(50)=375mg/kg) in comparison to the hexane extract (LD(50)>2900mg/kg). Results of the present study shows that Tilia americana var. mexicana possesses depressant activity on the CNS similar to the better-studied species of European Tilia and reinforces its use as anxiolytic and sedative in traditional medicine.

Evaluation of the enhanced oral effect of omapatrilat-monolein nanoparticles prepared by the emulsification-diffusion method.

In the present study, the emulsification-diffusion method was optimized in order to obtain omapatrilat/monolein-nanoparticles (omapatrilat/MO-nanoparticles). The antihypertensive effect of omapatrilat/MO-nanoparticles in spontaneously hypertensive rats (SHR) after oral administration was evaluated. The results indicated that the variables involved in the process did not have an influence on particle size, and that the former is directly determined by the amphiphilic properties of MO. When SHR were orally treated with omapatrilat/MO-nanoparticles, blood pressure was significantly reduced and completely normalized after three days. This effect was markedly higher than that observed with omapatrilat suspensions. The effect of omapatrilat/MO-nanoparticles can be attributed to: (i) The molecular dispersion of the drug into the lipophilic domain of monolein's bicontinuous phase; (ii) the adhesive properties of the nanodispersion on the gastrointestinal mucosa; (iii) the high surface area of the dispersion; (iv) the intraluminal interaction between MO, the mixed micelles arising from the digestive process, and omapatrilat; and (v) the well-known absorption-promoting properties of lipids, and in particular, of MO. MO-nanoparticles can be an interesting system to increase the oral bioavailability of drugs.

Neuropharmacological effects of an ethanol extract of the Magnolia dealbata Zucc. leaves in mice.

Magnolia dealbata Zucc. is considered to have tranquilizer and anticonvulsant properties in Mexican traditional medicine. In the present study we report the effects of a crude extract of Magnolia dealbata (30, 100 and 300 mg/kg) on mouse central nervous system (CNS). Pharmacological effects were tested on ambulatory activity, anti-anxiety response, sodium pentobarbital-induced hypnosis and pentylenetetrazole (PTZ)-induced seizures in comparison to honokiol, buspirone, ethosuximide and diazepam as corresponding reference drugs. No changes in spontaneous locomotor activity were produced posterior to Magnolia dealbata administration; however, a significant and dose-dependent diminution in the anxiety response was observed in experimental models such as plus-maze, head-dipping and exploratory rearing tests. Magnolia dealbata not only prolonged the time of sodium pentobarbital-induced hypnosis and delayed the onset of PTZ-induced mioclonus and clonus, but also hindered the presence of tonic seizures and avoided mortality. The hypnotic, anxiolytic and anticonvulsant effects obtained in these experiments support the hypothesis that Magnolia dealbata possesses CNS activity and reinforces the popular use in Mexican traditional medicine.

Anaplastic thyroid carcinoma in ecuador: analysis of prognostic factors.

The highest incidence of anaplastic thyroid carcinoma (ATC) has been reported in countries with endemic goiter, such as in Ecuador. In this country, ATC is the third most common histologic type of thyroid cancer, following papillary and follicular carcinoma. The aim of this study was to review the clinical presentation and the results of treatment of a large consecutive series of ATC patients treated at the oncological department of a general hospital in Quito, Ecuador. This is a retrospective study of 30 patients diagnosed with ATC at the Social Security Hospital, from 1982 to 1998. Symptomatic rapidly growing neck masses were generally present. All the patients had histological diagnosis of ATC. Two patients with pulmonary metastases and pleural effusion died before treatment could be instituted. Twenty-eight patients received at least one type of treatment: surgery, radiation therapy (RT), or chemotherapy (CT). The two most frequently employed therapeutic modalities were surgery followed by RT and/or CT in 14 patients and surgery alone in 9 patients. Surgery was performed in 23 patients but a complete resection was possible in only 14 patients. RT, postoperatively or alone, was given to 17 patients. Only 5 patients received doses ranging from 4,000 to 5,000 cGy and 4 patients more than 5,000 cGy. CT was administered to 17 patients. Doxorubicin alone was given to 10 patients and different combinations to the remaining patients. Local control was obtained in 8 of 14 complete resections. The prognostic value of the following parameters was studied by univariate analysis: duration of symptoms, size of the tumor, extent of glandular involvement, type of treatment, and surgical margins. A statistically longer survival was found in cases of differentiated carcinoma with areas of ATC or tumor limited to one lobe, those patients who received a complete treatment of chemotherapy, and those patients with tumors smaller than 10 cm and with duration of symptoms longer than 4 months. Longer mean survivals were seen in patients with longer duration of symptoms and smaller lesions. Five patients with focal anaplastic lesions within a differentiated thyroid carcinoma or a lesion limited to one lobe had a significant better survival (a mean of 20 months).

Sister-chromatid exchanges induced by disulfiram in bone marrow and spermatogonial cells of mice treated in vivo.

Disulfiram is a widely used drug to treat alcoholism due to its capacity to inhibit the metabolism of acetaldehyde; however, its genotoxic potential is not well known. Thus, the aim of this investigation was to determine whether the chemical may induce sister-chromatid exchanges (SCEs) in an in vivo study using mouse bone marrow and spermatogonial cells. We used doses of 200, 400 and 800 mg/kg body weight and compared the obtained data with the values determined in a negative control group as well as with a positive control group (cyclophosphamide, 50 mg/kg). The results in both systems indicated a weak genotoxic response by the chemical. In the case of bone marrow, a significant SCE level was achieved only with the high tested dose, but in spermatogonial cells the three doses tested showed a significant difference with respect to the negative control. No significant alterations in the mitotic index or in the cell proliferation kinetics were observed in somatic cells. Concerning the effect of cyclophosphamide, an increase in the level of SCEs was observed in both types of cells, reaching more than three times the values obtained in their respective control groups.

[Thyroglossal duct cysts]. / Quistes del conducto tirogloso.

INTRODUCTION: A thyroglossal cyst (TGC) is an unusual neck lesion that is occassionally diagnosed in a general hospital that mostly attend adult patients. The aim of the current study was to analyze our experience in the management of these lesions. MATERIAL AND METHODS: The records of 43 patients operated on at the Social Security Hospital in Quito (Ecuador) from 1980 to 1998 for a thyroglossal duct cyst or fistula, were reviewed. RESULTS: Distribution was similar in both sexes. Mean age was 23. Thirty-five patients presented with a cystic lesion located in the midline or slightly laterally in the neck, closely related to the hyoid bone; the other 8 patients had a cutaneous fistula at the same place. All of the patients but one, underwent a radical Sistrunk procedure; complications were minor. In 5 patients (12%), a papillary thyroid carcinoma within the TGC was reported at the histologic study. No recurrence developed after a mean 23-month follow-up. CONCLUSIONS: A cyst or a fistula located at the level of the hyoid bone suggest a thyroglossal duct lesion. A papillary carcinoma can rarely occur within the TGC. A Sistrunk procedure is usually curative.