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1.
B-ENT ; 12(3): 199-206, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-29727124

RESUMEN

PURPOSE: The success of stone removal with sialendoscopic lithotripsy in the management of lithiasis-related obstructive sialoadenitis has been reported, but the proper management for patients with non-lithiasis obstructive sialoadenitis remains unclear. This study aims to report experiences in sialendoscopy for the management of obstructive sialoadenitis with and without the presence of stones. METHODS: Data from 71 procedures in 66 patients who underwent sialendoscopy for obstructive sialoadenitis were recorded and compared in terms of clinical data, computed tomography (CT) findings, procedural techniques and outcomes. RESULTS: The overall specificity rate of CT for detecting sialolithiasis was 91.6%. The complete remission rate was 100% for patients with confirmed sialolithiasis successfully treated with stone removal after endoscopic lithotripsy. For patients with non-sialolithiasis obstructive sialoadenitis of the submandibular gland, the complete remission rate dropped to 22% if no additional treatments were done after a diagnostic sialendoscopy. If sialostents were inserted, the complete remission rate increased to 55%. However, this improvement was very limited in terms of the overall management of the affected parotid gland. CONCLUSION: For patients with obstructive sialoadenitis and salivary gland stones, removal of the stones under sialendoscopy will most likely provide complete remission. Patients without stones have much worse treatment outcomes compared to those with true sialolithiasis. Sialostent placement may have the potential to improve treatment outcomes in the management of non-lithiasis obstructive sialoadenitis.


Asunto(s)
Endoscopía , Sialadenitis/terapia , Adolescente , Adulto , Anciano , Niño , Preescolar , Femenino , Humanos , Litotripsia por Láser , Masculino , Persona de Mediana Edad , Inducción de Remisión , Estudios Retrospectivos , Cálculos de las Glándulas Salivales/complicaciones , Cálculos de las Glándulas Salivales/diagnóstico , Cálculos de las Glándulas Salivales/terapia , Sialadenitis/diagnóstico , Sialadenitis/etiología , Stents , Tomografía Computarizada por Rayos X , Adulto Joven
2.
Br J Surg ; 102(10): 1267-71, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26122401

RESUMEN

BACKGROUND: Altered immune function after appendicectomy has been associated with autoimmune disease, even though the mechanisms are not clearly elucidated. This study aimed to investigate whether the frequency of new-onset type II diabetes was increased after appendicectomy in a case-control study. METHODS: This was a retrospective cohort study from the Taiwan Longitudinal Health Insurance Database 2000. The relative risk was compared with that in the general population using population-based data. Each patient was tracked for a 3-year interval to identify those who developed type II diabetes. Cox proportional hazard regression analysis was used to assess the risk of type II diabetes during follow-up. RESULTS: A total of 31,512 patients were included in the study, of whom 5252 had an appendicectomy (study cohort) and 26,260 were matched for comparison. Some 714 patients (2.3 per cent) developed type II diabetes during the 3-year follow-up, 161 in the study cohort (3.1 per cent) and 553 in the comparison cohort (2.1 per cent). The adjusted hazard ratio (HR) for type II diabetes in the study cohort was 1.45 (95 per cent c.i. 1.22 to 1.74). This increased risk was most pronounced in men (adjusted HR 1.47, 1.16 to 1.88) and in those with a perforated appendix (adjusted HR 2.28, 1.71 to 3.03), and applied only to patients younger than 65 years of age. CONCLUSION: An increased risk of new-onset type II diabetes within 3 years after appendicectomy was found in patients aged less than 65 years. The risk was highest in men and in those with complicated appendicitis.


Asunto(s)
Apendicectomía/efectos adversos , Diabetes Mellitus Tipo 2/epidemiología , Medición de Riesgo/métodos , Adulto , Anciano , Apendicitis/cirugía , Diabetes Mellitus Tipo 2/etiología , Femenino , Estudios de Seguimiento , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Taiwán/epidemiología , Factores de Tiempo
3.
B-ENT ; 11(1): 57-61, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26513949

RESUMEN

PROBLEM/OBJECTIVE: Laser-assisted lithotripsy under sialendoscopy has the potential to overcome the limitations of traditional sialendoscopic lithotripsy when facing salivary stones. In this preliminary study, we report our experience with Holmium:YAG laser-assisted lithotripsy. METHODS: Data from 11 Asian patients receiving sialendoscopies for laser-assisted lithotripsy performed in our department from August 2013 to June 2014 were recorded and reviewed. RESULTS: A total of 18 procedures were performed in 11 Taiwanese patients with symptoms of obstructive sialoadenitis who were diagnosed with sialolithiasis. The sizes of the stones ranged between 3 mm and 13 mm. The endoscopic lithotomy procedures were performed in all 11 patients, and stone fragmentation with the Holmium:YAG laser was done successfully in all patients. All patients were followed for a minimum of 3 months, and there was no evidence of complications or recurrences over the follow up period. CONCLUSION: The Holmium:YAG laser allowed successful fragmentation of stones in all 11 patients. Our experience with this procedure supports the use of Holmium:YAG laser-assisted lithotripsy through sialendoscopy in Asian patients.


Asunto(s)
Endoscopía , Láseres de Estado Sólido/uso terapéutico , Litotricia/métodos , Cálculos de las Glándulas Salivales/cirugía , Adolescente , Adulto , Anciano , Femenino , Holmio , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven
4.
Rhinology ; 52(2): 156-161, 2014 06.
Artículo en Inglés | MEDLINE | ID: mdl-24932628

RESUMEN

BACKGROUND: The Venturi-principle atomizer is a commonly used device in otolaryngology practices. The purpose of this study is to evaluate the possible route of bacterial contamination from the nasal vestibule to the atomizer tip through the jet airflow created during the use of the Venturi atomizer. METHODS: Thirty nostrils from 15 enrolled volunteers were tested. The aerosols generated by spraying sterilized saline into the nostrils were collected using a specially made aerosol-collecting nozzle cap. The collected samples were sent for bacterial culture, and nasal vestibular swab cultures were performed for comparison. RESULTS: In the aerosol-exposed group, 18 out of 30 samples (60%) were positive for bacterial growth, confirming the bacterial contamination from the nasal vestibule to the atomizer tip through the reverse jet airflow. The bacteria species in 8 of the 18 positive samples were identical to those from the nasal swab culture results from the same nostril. CONCLUSION: In ordinary otolaryngology practices, there are significant risks for bacterial contamination from the nasal vestibule to the tip of the Venturi atomizer even without direct contact. Clinicians must be more aware of this pattern of contamination, which has not been reported in the existing literature.


Asunto(s)
Contaminación de Equipos , Cavidad Nasal/microbiología , Nebulizadores y Vaporizadores/microbiología , Otolaringología/instrumentación , Administración Intranasal/instrumentación , Enterobacteriaceae/aislamiento & purificación , Diseño de Equipo , Humanos , Rociadores Nasales , Staphylococcus/aislamiento & purificación
5.
J Chem Phys ; 139(20): 204702, 2013 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-24289364

RESUMEN

We grew graphene epitaxially on 6H-SiC(0001) substrate by the simulated annealing method. The mechanisms that govern the growth process were investigated by testing two empirical potentials, namely, the widely used Tersoff potential [J. Tersoff, Phys. Rev. B 39, 5566 (1989)] and its more refined version published years later by Erhart and Albe [Phys. Rev. B 71, 035211 (2005)]. Upon contrasting the results obtained by these two potentials, we found that the potential proposed by Erhart and Albe is generally more physical and realistic, since the annealing temperature at which the graphene structure just coming into view at approximately 1200 K is unambiguously predicted and close to the experimentally observed pit formation at 1298 K within which the graphene nucleates. We evaluated the reasonableness of our layers of graphene by calculating carbon-carbon (i) average bond-length, (ii) binding energy, and (iii) pair correlation function. Also, we compared with related experiments the various distance of separation parameters between the overlaid layers of graphene and substrate surface.

6.
Eur J Clin Invest ; 39(4): 296-303, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19292885

RESUMEN

BACKGROUND: Previous reports have indicated that statins could prevent bone loss in ovariectomized (OVX) rats and increase the expressions of osteogenic genes in cultured osteoblasts. In this study, we hypothesized that simvastatin might increase osteoblast number and protein expressions of osteogenic markers localized in bones in concomitance with the prevention of bone loss in OVX rats. MATERIALS AND METHODS: Fifty-four 3-month-old OVX and sham-operated (SHAM) female Sprague-Dawley rats were used. Simvastatin (10-20 mg kg(-1) day(-1)) was administrated orally for 6 weeks. Trabecular volume, osteoblast number and osteogenic proteins including BMP2, collagen type I and osteocalcin on bone sections obtained from lumbar vertebral body, distal femur and proximal tibia were measured. RESULTS: The results showed that SHAM rats had significantly less trabecular bone volume and osteoblast number than that of OVX rats 6 weeks after operation. Oral simvastatin treatment (10-20 mg kg(-1) day(-1)) increased bone volume and osteoblast number in the distal femurs, proximal tibiae and vertebrae of OVX rats. Furthermore, the osteoblastic cells with immuno-stained BMP2, collagen type I and osteocalcin in vertebral bones were significantly increased by simvastatin treatment (20 mg kg(-1) day(-1)) in OVX rats. CONCLUSIONS: This study demonstrates that simvastatin enhances the production of osteogenic proteins in bone and this effect may contribute to the prevention of bone loss in OVX rats.


Asunto(s)
Densidad Ósea/efectos de los fármacos , Proteínas Morfogenéticas Óseas/efectos de los fármacos , Huesos/efectos de los fármacos , Osteoblastos/efectos de los fármacos , Simvastatina/farmacología , Análisis de Varianza , Animales , Modelos Animales de Enfermedad , Femenino , Ovariectomía , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley
7.
Eur Rev Med Pharmacol Sci ; 23(13): 5548-5557, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31298306

RESUMEN

OBJECTIVE: To compare two different Ho:YAG laser systems in relation to the preset parameters and their effectiveness for intraductal fragmentation of the salivary stones. PATIENTS AND METHODS: We made a retrospective study in two tertiary referral centers (Department of ENT, Head and Neck Surgery, University of Erlangen-Nuremberg, Germany and the MacKay Memorial Hospital, Taipei, Taiwan). Patients with a diagnosis of sialolithiasis were treated in Erlangen and Taipei. The Erlangen patients were treated using the Calculase II™ Ho:YAG laser (Karl Storz, Tuttlingen, Germany) at 4 Hz, 1.2 J (4.8 W) and the MacKay patients were treated using the VersaPulse® PowerSuite™ Ho:YAG laser (Lumenis Ltd., Yokneam, Israel) at 6 Hz, 0.5 J (3 W). RESULTS: A total of 12 patients with 12 stones were treated in Erlangen and 54 with 75 stones in Taipei. The submandibular stones were present in 50% and 86.7% of cases, respectively. The complete fragmentation was achieved in all of the treated stones in both groups; 100% and 92.6% of the patients were stone-free, 100% and 94.4% of the patients became symptom-free, respectively. 33% of the Erlangen patients had multimodal treatments. The glands were preserved in all cases in both centers. CONCLUSIONS: The Ho:YAG laser proved to be effective in the treatment of sialolithiasis. Stone size, location, and involved gland were important additional parameters. Our experience and the literature results show that the laser presetting with a frequency of 3-6 Hz, an energy level of 0.5-1.2 J, and effective power of between 3 and 4.8 W is sufficient to achieve maximum success without any increased risk for complications.


Asunto(s)
Láseres de Estado Sólido , Litotricia/métodos , Cálculos de las Glándulas Salivales/terapia , Adolescente , Adulto , Anciano , Niño , Femenino , Humanos , Litotricia/instrumentación , Masculino , Persona de Mediana Edad , Glándula Parótida/patología , Estudios Retrospectivos , Glándula Submandibular/patología , Centros de Atención Terciaria , Resultado del Tratamiento , Adulto Joven
8.
Eur Respir J ; 32(3): 651-9, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18508824

RESUMEN

The application of a supervised endurance exercise training programme in a home setting offering convenience and prolonged effects is a challenge. In total, 48 patients were initially assessed by the incremental shuttle walk test (ISWT), spirometry and the Short Form-12 (SF-12) quality-of-life questionnaire, and then every 4 weeks for 3 months thereafter and again after 1 yr. During the first 3 months, 24 patients in the cell phone group were asked to perform daily endurance walking at 80% of their maximal capacity by following the tempo of music from a program installed on a cell phone. The level of endurance walking at home was readjusted monthly according to the result of ISWT. In the control group, 24 patients received the same protocol and were verbally asked to take daily walking exercise at home. Patients in the cell phone group significantly improved their ISWT distance and duration of endurance walking after 8 weeks. The improvements in ISWT distance, inspiratory capacity and SF-12 scoring at 12 weeks persisted until the end of the study, with less acute exacerbations and hospitalisations. In the present pilot study, the cell phone-based system provides an efficient, home endurance exercise training programme with good compliance and clinical outcomes in patients with moderate-to-severe chronic obstructive pulmonary disease.


Asunto(s)
Teléfono Celular , Terapia por Ejercicio/métodos , Enfermedad Pulmonar Obstructiva Crónica/rehabilitación , Anciano , Tolerancia al Ejercicio , Femenino , Humanos , Masculino , Música , Cooperación del Paciente , Proyectos Piloto , Calidad de Vida
9.
J Laryngol Otol ; 130(6): 521-5, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27117586

RESUMEN

BACKGROUND: This study aimed to evaluate the association of chronic rhinosinusitis with sudden sensorineural hearing loss using a population-based database. METHODS: Sampled subject data were obtained from the Taiwan Longitudinal Health Insurance Database 2000. A total of 3325 patients with sudden sensorineural hearing loss were identified and 9975 controls were randomly selected. A conditional logistic regression was used to calculate the odds ratio for having been previously diagnosed with chronic rhinosinusitis, for cases and controls. RESULTS AND CONCLUSION: The adjusted odds ratio of having prior chronic rhinosinusitis among cases compared to controls was 1.36 (95 per cent confidence interval = 1.16-1.60). The significant relationship between sudden sensorineural hearing loss and chronic rhinosinusitis was most pronounced among those patients aged 44 years or less (compared to controls) (odds ratio = 2.18; 95 per cent confidence interval = 1.63-2.92). However, the significant relationship between sudden sensorineural hearing loss and prior chronic rhinosinusitis was not sustained for patients older than 60 years compared to controls.


Asunto(s)
Pérdida Auditiva Súbita/epidemiología , Rinitis/epidemiología , Sinusitis/epidemiología , Adulto , Factores de Edad , Anciano , Estudios de Casos y Controles , Enfermedad Crónica , Enfermedad Coronaria/epidemiología , Bases de Datos Factuales , Diabetes Mellitus/epidemiología , Femenino , Humanos , Hiperlipidemias/epidemiología , Hipertensión/epidemiología , Enfermedades Renales/epidemiología , Modelos Logísticos , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Taiwán/epidemiología
10.
Biochim Biophys Acta ; 1090(2): 255-8, 1991 Oct 08.
Artículo en Inglés | MEDLINE | ID: mdl-1932120

RESUMEN

A genomic DNA clone containing Chinese hamster metallothionein II (MTII) gene and its 5' flanking region was isolated from Cd resistant Chinese hamster ovary (CHO) cells. DNA sequence analysis showed that there are three exons and two introns in the structure of the MTII gene. Further characterization of the 5' flanking region reveals the possible transcription initiation site, metal responsive element and basal-level enhancer sequence. Putatively, this is the promoter region of CHO MTII gene.


Asunto(s)
ADN/análisis , Metalotioneína/genética , Regiones Promotoras Genéticas , Animales , Secuencia de Bases , Línea Celular , Clonación Molecular , Cricetinae , Cricetulus , Exones , Intrones , Datos de Secuencia Molecular
11.
Biochim Biophys Acta ; 1294(1): 89-97, 1996 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-8639720

RESUMEN

Plant vacuolar vesicles contain a novel H(+)-translocating pyrophosphatase (H(+)-PPase, EC 3.6.1.1). Modification of tonoplast vesicles and purified vacuolar H(+)-PPase from etiolated mung bean seedlings with tetranitromethane (TNM) resulted in a progressive decline in H(+)-translocating pyrophosphatase activity. The half-maximal inhibition was brought about by 0.6, 1.0, and 0.8 mM TNM for purified and membrane-bound H(+)-PPases, and its associated proton translocation, respectively. The maximal inhibition of vacuolar H(+)-PPase by TNM occurred at a pH value above 8. Loss of activity of purified H(+)-pyrophosphatase followed pseudo-first order rate kinetics, yielding a first-order rate constant (k2) of 0.039 s(-1) and a steady-state dissociation constant of inactivation (Ki) of 0.02 mM. Covalent modification of vacuolar H(+)-PPase by TNM increased Km value of the enzyme for its substrate without a significant effect on Vmax. Double logarithmic plots of the pseudo-first order rate constant (kobs) versus TNM concentration exhibited a slope of 0.88, suggesting that at least one tyrosine residue was involved in the inactivation of H(+)-PPase enzymatic activity. Further spectrophotometric measurements of the nitrated H(+)-pyrophosphatase indicated that TNM could modify approximately two tyrosine residues/subunit of the enzyme. However, Tsou's analysis revealed that only one of those modified tyrosine residues directly participated in the inhibition of enzymatic activity of vacuolar H(+)-PPase. The physiological substrate, i.e., dimagnesium pyrophosphate, provided substantial protection against inactivation by TNM. Moreover, NEM pretreatment of the enzyme decreased the number of subsequent nitration of vacuolar H(+)-PPase. Taken together, we suggest that vacuolar H(+)-pyrophosphatase contains a substrate-protectable tyrosine residue conferring to the inhibition of its activity and this tyrosine residue may be located in a domain sensitive to the modification of Cys-634 by NEM.


Asunto(s)
Inhibidores Enzimáticos/farmacología , Fabaceae/enzimología , Plantas Medicinales , Pirofosfatasas/antagonistas & inhibidores , Tetranitrometano/farmacología , Tirosina/metabolismo , Vacuolas/enzimología , Electroforesis en Gel de Poliacrilamida , Pirofosfatasa Inorgánica , Cinética , Pirofosfatasas/aislamiento & purificación , Pirofosfatasas/metabolismo , Espectrofotometría
12.
Protein Sci ; 8(10): 2001-9, 1999 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-10548045

RESUMEN

Members of the aspartic proteinase family of enzymes have very similar three-dimensional structures and catalytic mechanisms. Each, however, has unique substrate specificity. These distinctions arise from variations in amino acid residues that line the active site subsites and interact with the side chains of the amino acids of the peptides that bind to the active site. To understand the unique binding preferences of plasmepsin II, an enzyme of the aspartic proteinase class from the malaria parasite, Plasmodium falciparum, chromogenic octapeptides having systematic substitutions at various positions in the sequence were analyzed. This enabled the design of new, improved substrates for this enzyme (Lys-Pro-Ile-Leu-Phe*Nph-Ala/Glu-Leu-Lys, where * indicates the cleavage point). Additionally, the crystal structure of plasmepsin II was analyzed to explain the binding characteristics. Specific amino acids (Met13, Ser77, and Ile287) that were suspected of contributing to active site binding and specificity were chosen for site-directed mutagenesis experiments. The Met13Glu and Ile287Glu single mutants and the Met13Glu/Ile287Glu double mutant gain the ability to cleave substrates containing Lys residues.


Asunto(s)
Ácido Aspártico Endopeptidasas/metabolismo , Ácido Aspártico Endopeptidasas/química , Ácido Aspártico Endopeptidasas/genética , Sitios de Unión , Hemoglobinas/química , Cinética , Mutagénesis Sitio-Dirigida , Conformación Proteica , Proteínas Protozoarias , Especificidad por Sustrato
13.
Methods Enzymol ; 246: 19-34, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-7538624

RESUMEN

Absorption and CD measurements of complementary oligomers and mixtures are described. The concentrations of oligomers may be estimated from absorption measurements and nearest-neighbor calculations of molar extinction coefficients. Interactions between complementary strands in mixtures can lead to obvious differences between measured CD spectra and the average of the spectra of the individual strands. CD spectra also allow an assessment of whether the individual strands are in self-complexes, which could compete with duplex or triplex formation. Isodichroic and isoabsorptive points provide important indicators of the stoichiometry of the strands in base-paired complexes. CD spectra provide an important means of characterizing differences in the conformations of DNA, RNA, and hybrid duplexes or triplexes having analogous sequences.


Asunto(s)
Dicroismo Circular , ADN/química , Conformación de Ácido Nucleico , Oligorribonucleótidos/química , ARN/química , Espectrofotometría Ultravioleta/métodos , Fosfatos de Dinucleósidos/química , Sustancias Macromoleculares , Ribonucleótidos/química
14.
Am J Kidney Dis ; 37(2): 427-30, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11157387

RESUMEN

Thiamine deficiency is mainly encountered in alcoholics or food faddists, but it may complicate chronic dialysis because of low intake and accelerated loss of thiamine in dialysis patients. We report here 2 hemodialysis (HD) patients who developed chorea induced by thiamine deficiency. We propose that thiamine deficiency, with a consequent dysfunction of the basal ganglia, may induce chorea in HD patients.


Asunto(s)
Corea/etiología , Diálisis Renal/efectos adversos , Deficiencia de Tiamina/complicaciones , Anciano , Humanos , Fallo Renal Crónico/complicaciones , Fallo Renal Crónico/terapia , Masculino , Persona de Mediana Edad
15.
Am J Kidney Dis ; 38(5): 941-7, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11684545

RESUMEN

Patients with end-stage renal disease undergoing regular dialysis are prone to encephalopathy, but the cause is often unclear. Dialysis patients are at risk for thiamine deficiency, which may mimic many uremic complications, including encephalopathy. To determine whether unexplained encephalopathy in regular dialysis patients is associated with thiamine deficiency, we conducted a prospective study that enrolled 30 consecutive dialysis patients with altered mental status admitted to a referred hospital during a 1-year period. A complete history, physical and neurological examinations, laboratory investigations, and computed tomographic scans or magnetic resonance imaging of the brain were obtained for each subject. In 10 of the 30 patients, diagnoses remained obscure after the initial workup. Manifestations included confusion, chorea, acute visual loss, rapidly progressive dementia, myoclonus, convulsions, and coma. Intravenous thiamine was administered to these 10 patients. All 10 patients had thiamine deficiency confirmed by a marked response to thiamine supplementation and/or a low serum thiamine concentration (35.3 +/- 6.0 nmol/L; normal, >50 nmol/L). Nine patients recovered, but one patient failed to respond because of delayed treatment. We conclude that in regular dialysis patients, unexplained encephalopathy can be mainly attributed to thiamine deficiency. This condition is fatal if unrecognized and can be successfully treated with prompt thiamine replacement.


Asunto(s)
Diálisis Peritoneal , Diálisis Renal , Deficiencia de Tiamina/complicaciones , Encefalopatía de Wernicke/patología , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Inyecciones Intravenosas , Fallo Renal Crónico/complicaciones , Fallo Renal Crónico/terapia , Masculino , Persona de Mediana Edad , Tasa de Supervivencia , Tiamina/sangre , Tiamina/uso terapéutico , Deficiencia de Tiamina/tratamiento farmacológico , Deficiencia de Tiamina/mortalidad , Resultado del Tratamiento , Encefalopatía de Wernicke/tratamiento farmacológico , Encefalopatía de Wernicke/etiología
16.
IEEE Trans Pattern Anal Mach Intell ; 1(1): 100-9, 1979 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21868838

RESUMEN

A natural generalization of two-dimensional digital pulsecode modulations (DPCM) has been used to handle the compression of images for human eyes only. It shows that by ignoring the mean-square error (MSE) and wisely arranging the errors in the right place, a simple method can achieve very good results.

17.
IEEE Trans Pattern Anal Mach Intell ; 7(2): 203-15, 1985 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21869257

RESUMEN

The straightness of a digital arc can simply be determined by the absence of unevenness in its chain code. The absence of unevenness is a necessary and sufficient condition for a digital arc to have the chord property, and it offers a much simpler alternative for examining whether a digital arc has the chord property or not. This condition is also the most comprehensive and precise expression of the third criterion about digital straight lines given by Freeman. The relations among the chord property, Freeman's three criteria, and the hierarchical structure that a digital straight line supposedly have become much more clear. A procedure to detect the uneven segments and algorithms for determining the straightness of digital arcs is also included.

18.
J Formos Med Assoc ; 96(10): 812-8, 1997 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9343981

RESUMEN

A decline in sexual arousal and copulatory activity has been observed in male rats with advancing age. Grafting of fetal hypothalamic tissue into the third ventricle of aged male rats restores sexual behavior. This study investigated the effects of grafting fetal preoptic area (POA) neurons into the POA of aged male rats exhibiting decreased sexual behavior. We grafted suspensions of fetal POA neurons into the POA of 20 aged (19 to 24 months old) male rats that displayed no ejaculation. From 2 weeks after grafting, one or more series of male copulatory activity and sexual motivation tests were performed at intervals of 3 to 4 weeks. Three behavioral tests given 5 days apart were repeated for each animal in each series. Among the 20 aged rats with the fetal grafts, 15 showed improved sexual motivation, and 14 of these had copulatory activity restored to levels comparable with those of young males. Among these 14 rats, eight ejaculated during copulation. Copulatory behavior was restored between 21 and 45 days after grafting and persisted until the end of observation (2-4.5 months). Sexual performance did not improve in control aged male rats grafted with either fetal cerebral cortex neurons into the POA or POA, neurons into the ventromedial hypothalamus. The rats that received grafts of fetal POA neurons into the POA and recovered sexual performance also showed improvement or recovery to levels comparable to those in young males of serum testosterone concentrations, serum luteinizing hormone levels after castration, and the post-castration rise in luteinizing hormone. These results indicate that decreases in copulatory activity, sexual motivation, and some neuroendocrine functions in aged male rats are at least partially due to dysfunction of the POA.


Asunto(s)
Envejecimiento/fisiología , Trasplante de Tejido Encefálico , Trasplante de Tejido Fetal , Área Preóptica/fisiología , Conducta Sexual Animal , Animales , Hormona Luteinizante/sangre , Masculino , Ratas , Testosterona/sangre
19.
J Am Dent Assoc ; 129(7): 1014-21, 1998 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9685767

RESUMEN

While being shipped to a laboratory, impressions can be exposed to excessive temperatures. This study compared the effects of different time and temperature storage conditions, including temperature extremes of 66 C and -10 C, on the accuracy of addition silicone and polyether impressions. The greatest distortion generally occurred as a result of the 66 C temperature extreme. The authors recommend that impressions be poured in stone according to manufacturers' specifications before being shipped to a dental laboratory.


Asunto(s)
Materiales de Impresión Dental/química , Éteres/química , Polímeros/química , Polivinilos/química , Siloxanos/química , Sulfato de Calcio/química , Fenómenos Químicos , Química Física , Frío , Revestimiento para Colado Dental/química , Técnica de Colado Dental , Técnica de Impresión Dental/instrumentación , Calor , Ensayo de Materiales , Modelos Dentales , Resinas Sintéticas/química , Acero Inoxidable , Propiedades de Superficie , Temperatura , Factores de Tiempo
20.
Am J Dent ; 3(6): 249-52, 1990 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-2095804

RESUMEN

Often times light-body wash (LB) cannot be added to the heavy-body putty (HB) within 30 minutes when utilizing the two-step reline impression technique. The purpose of this study was to add the LB to the HB at times greater than 30 minutes and test the tensile bond strength. A split aluminum mold which created a bonding area of 1.13 cm2 and tray were filled with Express HB. After HB set the Express LB in a tray was added at varying times. The split molds were then separated and samples tested on the Instron. Ten groups with five samples/group (determined by a pilot study) were made. The times which the LB was added to the set HB and tested were: A) Immediately (one-step procedure); B) 10 minutes and contaminated with saliva (negative control); C) 10 minutes; D) 30 minutes; E) 45 minutes; F) 1 hour; G) 3 hours; H) 24 hours; I) 115 hours; and J) Freshened after 3 months. The results of this study indicate that saliva-contaminated samples were weaker than all other groups (P less than or equal to 0.01) and as far as tensile bond strength between materials is concerned, there appears to be no detrimental effect in tensile bond strength between HB and LB when delaying the application of the light-body material (P less than or equal to 0.01).


Asunto(s)
Recubrimiento Dental Adhesivo , Materiales de Impresión Dental , Técnica de Impresión Dental , Polivinilos , Siloxanos , Resistencia a la Tracción , Factores de Tiempo
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