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1.
J Am Chem Soc ; 142(51): 21469-21483, 2020 12 23.
Artículo en Inglés | MEDLINE | ID: mdl-33290059

RESUMEN

This work explores the mechanism whereby a cationic diimine Pd(II) complex combines coordination insertion and radical polymerization to form polyolefin-polar block copolymers. The initial requirement involves the insertion of a single acrylate monomer into the Pd(II)-polyolefin intermediates, which generate a stable polymeric chelate through a chain-walking mechanism. This thermodynamically stable chelate was also found to be photochemically inactive, and a unique mechanism was discovered which allows for radical polymerization. Rate-determining opening of the chelate by an ancillary ligand followed by additional chain walking allows the metal to migrate to the α-carbon of the acrylate moiety. Ultimately, the molecular parameters necessary for blue-light-triggered Pd-C bond homolysis from this α-carbon to form a carbon-centered macroradical species were established. This intermediate is understood to initiate free radical polymerization of acrylic monomers, thereby facilitating block copolymer synthesis from a single Pd(II) complex. Key intermediates were isolated and comprehensively characterized through exhaustive analytical methods which detail the mechanism while confirming the structural integrity of the polyolefin-polar blocks. Chain walking combined with blue-light irradiation functions as the mechanistic switch from coordination insertion to radical polymerization. On the basis of these discoveries, robust di- and triblock copolymer syntheses have been demonstrated with olefins (ethylene and 1-hexene) which produce amorphous or crystalline blocks and acrylics (methyl acrylate, ethyl acrylate, n-butyl acrylate, and methyl methacrylate) in broad molecular weight ranges and compositions, yielding AB diblocks and BAB triblocks.

2.
Anal Chem ; 92(23): 15596-15603, 2020 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-33169611

RESUMEN

Polyolefins are important and broadly used materials. Their molecular microstructures have direct impact on macroscopic properties and dictate end-use applications. 13C NMR is a powerful analytical technique used to characterize polyolefin microstructures, such as long-chain branching (LCB), but it suffers from low sensitivity. Although the 13C sensitivity of polyolefin samples can be increased by about 5.5 times with a cryoprobe, when compared with a conventional broadband observe (BBO) probe, further sensitivity enhancement is in high demand for studying increasingly complex polyolefin microstructures. Toward this goal, distortionless enhancement by polarization transfer (DEPT) and refocused insensitive nuclei enhanced by polarization transfer (RINEPT) are explored. The use of hard, regular, and new short adiabatic 180° 13C pulses in DEPT and RINEPT is investigated. It is found that RINEPTs perform better than DEPTs and a sensitivity enhancement of 3.1 can be achieved with RINEPTs. The results of RINEPTs are further analyzed with statistics software JMP and recommendations for optimal usage of RINEPTs are suggested. An example of analyzing saturated chain ends in an ethylene-octene copolymer sample with a hard 180° 13C RINEPT pulse is demonstrated. It is shown that the experimental time can be further reduced in half because of faster proton relaxation, where the total experimental time is about 580 times shorter when compared to using a conventional method and a 10 mm BBO probe. A naturally abundant nitrogen-containing polyolefin is analyzed using 1H-15N HMBC and, to our knowledge, is the first 1H-15N HMBC presented in the field of polyolefin characterization. The relative amount of similar nitrogen-containing structures is quantified by two-dimensional integration of 1H-15N HMBC. Two pragmatic technical challenges related to using high-sensitivity NMR cryoprobes are also addressed: (1) A new 1H decoupling sequence Bi_Waltz_65_256pl is proposed to address decoupling artifacts in 13C{1H} NMR spectra which contain a strong 13C signal with a high signal-to-noise ratio (S/N). (2) A simple pulse sequence that affords zero-slope spectral baselines and quantitative results is presented to address acoustic ringing that is often associated with high-sensitivity cryoprobe use.

3.
Angew Chem Int Ed Engl ; 58(36): 12370-12391, 2019 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-30791191

RESUMEN

The inherent differences in reactivity between activated and non-activated alkenes prevents copolymerization using established polymer synthesis techniques. Research over the past 20 years has greatly advanced the copolymerization of polar vinyl monomers and olefins. This Review highlights the challenges associated with conventional polymerization systems and evaluates the most relevant methods which have been developed to "bridge the gap" between polar vinyl monomers and olefins. We discuss advancements in heteroatom tolerant coordination-insertion polymerizations, methods of controlling radical polymerizations to incorporate olefinic monomers, as well as combined approaches employing sequential polymerizations. Finally, we discuss state-of-the-art stimuli-responsive systems capable of facile switching between catalytic pathways and provide an outlook towards applications in which tailored copolymers are ideally suited.

4.
Optom Vis Sci ; 87(8): 604-11, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20512081

RESUMEN

PURPOSE: To evaluate the effect of non-penetrating corneal foreign bodies secondary to explosive blasts on the visual performance of soldiers. METHODS: In a prospective, non-interventional study subjective visual performance and objective optical quality of 11 injured eyes with retained corneal foreign bodies were compared with that of 11 normal controls. Visual performance measures consisted of best spectacle-corrected high-contrast visual acuity (HCVA), low-contrast (5%) visual acuity (LCVA), and contrast sensitivity (CS). LCVA was evaluated in two luminance levels (photopic and mesopic) and two glare conditions (with and without glare). Acuity measurements were scored using logMAR notation. Objective optical quality was assessed comparing total root mean square wavefront error (WFE) and percent higher order aberrations. Modulation transfer functions calculated from the wavefront maps were used to predict the results of the psychophysical contrast testing. RESULTS: HCVA of injured eyes (M = -0.03) did not differ significantly (t(20) = 1.56, p = 0.13) when compared with controls (M = -0.09). However, visual performance of injured eyes (M = 0.33) was significantly worse than control eyes (M = 0.11) on photopic LCVA (t(20) = 4.16, p < 0.001), mesopic LCVA(M = 0.44 vs. M = 0.21, t(20) = 3.85, p = 0.001), mesopic LCVA with glare (M = 0.49 vs. M = 0.21, t(20) = 3.66, p = 0.002), and small letter CS (M = 0.25 vs. M = 0.90, t(20) = -6.6, p < 0.001). For a 6-mm pupil, mean absolute WFE attributed to higher order aberrations for the injured eyes was 0.86 microm and 0.59 microm for the control eyes. This difference was significant (t(20) = -2.15, p = 0.044). CONCLUSIONS: Although HCVA was no different than the normal controls, visual performance of the injured eyes was significantly worse in terms of LCVA and CS. On average, visual performance can be broadly predicted by the modulation transfer function derived from the subjects' wavefront aberration map.


Asunto(s)
Traumatismos por Explosión/complicaciones , Córnea , Cuerpos Extraños en el Ojo/etiología , Cuerpos Extraños en el Ojo/fisiopatología , Visión Ocular , Adulto , Anteojos , Femenino , Deslumbramiento , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Psicofísica , Refracción Ocular , Agudeza Visual , Adulto Joven
5.
Mil Med ; 172(5): 491-7, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17521096

RESUMEN

We retrospectively reviewed the records of 107 U.S. military personnel referred to the Walter Reed Army Medical Center ophthalmology service with eye diseases and nonbattle injuries diagnosed during Operation Enduring Freedom and Operation Iraqi Freedom. Ocular diseases and nonbattle injuries ranged from minor to vision-threatening, represented a broad variety of conditions, and required the expertise of a number of ophthalmic subspecialists. The most common diagnoses were uveitis (13.1%), retinal detachment (11.2%), infectious keratitis (4.7%), and choroidal neovascularization (4.7%). Eighty-four patients (78.5%) met Army retention standards and were returned to duty. Twenty patients (18.7%) were referred to a medical evaluation board, seven (6.5%) of whom failed to meet retention standards for eye and vision; the retention status of three patients (2.8%) remains to be determined.


Asunto(s)
Oftalmopatías/diagnóstico , Lesiones Oculares/diagnóstico , Hospitales Militares/estadística & datos numéricos , Personal Militar/estadística & datos numéricos , Terrorismo , Guerra , Adulto , Estudios Transversales , Demografía , District of Columbia/epidemiología , Oftalmopatías/epidemiología , Lesiones Oculares/epidemiología , Femenino , Humanos , Irak , Masculino , Persona de Mediana Edad , Medicina Militar , Estudios Retrospectivos , Revisión de Utilización de Recursos
6.
J Control Release ; 244(Pt B): 366-374, 2016 12 28.
Artículo en Inglés | MEDLINE | ID: mdl-27411978

RESUMEN

Polyglycidol-based nanohydrogels (nHGs) have been prepared by optimizing the use of liposome master templates resulting in a high-yielding and more practical one-pot process to provide materials capable of carrying drugs of adverse chemical nature. The nanogels prepared with the one-pot method showed favorable kinetics for the release of either Nile Red (NR) or lysozyme (LYS), loaded with gel precursors such as semi-branched poly(glycidol allylglycidyl ether), PEG dithiol (1KDa), a free radical initiator and liposomal lipids at the liposome formation step. This process is superior to a comparable step-wise traditional approach and circumvents loading of the gel precursors with the hydrophilic drug into preformed liposome templates. A thiol-ene crosslinking reaction accomplishes the formation of the nanonetwork resulting in nHGs prepared in the traditional step-wise (nHG-SW) approach and the one-pot (nHG-OP) process. Both nanogel networks were characterized in terms of particle size and zeta (ζ) potential with average values of 148nm±39nm and -25.9mV±9.2 for the nHG-SW and 132nm±32 and -23.1mV±9.7 for the nHG-OPs. Loading efficiency for both of the nanogels with NR was determined by spectrophotometry to be 28% (nHP-SW) and 31% (nHP-OP). The LYS loading was based on the target loading of 10µg/mg for both nanogels found to be 84% and 86% for the nHG-SW and nHP-OP, respectively. As proof of concept for combination drug delivery, the in vitro release of both drug mimics, NR and LYS, were monitored under physiologically relevant conditions by an optimized dialysis method. The implementation of the multi-functional and semi-branched polyglycidol is recognized as the main contributor for the observed highly controlled release of proteins that are otherwise rapidly released from common PEG-based nanogel networks. Furthermore, the one-pot process led to be the most favorable drug delivery system based on the release kinetics pointing to a denser polymer network.


Asunto(s)
Sistemas de Liberación de Medicamentos , Nanopartículas/química , Glicoles de Propileno/química , Liberación de Fármacos , Interacciones Hidrofóbicas e Hidrofílicas , Liposomas , Muramidasa/administración & dosificación , Muramidasa/química , Nanopartículas/administración & dosificación , Oxazinas/administración & dosificación , Oxazinas/química , Tamaño de la Partícula , Glicoles de Propileno/administración & dosificación
7.
J Control Release ; 220(Pt B): 751-7, 2015 Dec 28.
Artículo en Inglés | MEDLINE | ID: mdl-26344396

RESUMEN

We report the synthesis and encapsulation of polyester nanosponge particles (NPs) co-loaded with tamoxifen (TAM) and quercetin (QT) to investigate the loading, release and in vitro metabolism of a dual drug formulation. The NPs are made in two variations, 4% and 8% crosslinking densities, to evaluate the effects on metabolism and release kinetics. The NP-4% formulation with a particle size of 89.3 ± 14.8 nm was found to have loading percentages of 6.91 ± 0.13% TAM and 7.72 ± 0.15% QT after targeting 10% (w/w) each. The NP-8% formulation with a particle size of 91.5 ± 9.8 nm was found to have loading percentages of 7.26 ± 0.10% TAM and 7.80 ± 0.12% QT. The stability of the formulation was established in simulated gastrointestinal fluids, and the metabolism of TAM was shown to be reduced 2-fold and 3-fold for NP-4%s and NP-8%s, respectively, while QT metabolism was reduced 3 and 4-fold. The implications for improved bioavailability of the NP formulations were supported by cytotoxicity results that showed a similar efficacy to free dual drug formulations and even enhanced anti-cancer effects in the recovery condition. This work demonstrates the suitability of the nanosponges not only as a dual release drug delivery system but also enabling a regulated metabolism through the capacity of a nanonetwork. The variation in crosslinking enables a dual release with tailored release kinetics and suggests improved bioavailability aided by a reduced metabolism.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Neoplasias de la Mama/tratamiento farmacológico , Portadores de Fármacos , Nanopartículas , Poliésteres/química , Quercetina/farmacología , Tamoxifeno/farmacología , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/química , Protocolos de Quimioterapia Combinada Antineoplásica/metabolismo , Disponibilidad Biológica , Biotransformación , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Química Farmacéutica , Reactivos de Enlaces Cruzados/química , Citocromo P-450 CYP3A/metabolismo , Preparaciones de Acción Retardada , Relación Dosis-Respuesta a Droga , Estabilidad de Medicamentos , Femenino , Jugo Gástrico/química , Glucuronosiltransferasa/metabolismo , Secreciones Intestinales/química , Cinética , Ratones , Nanomedicina/métodos , Tamaño de la Partícula , Quercetina/administración & dosificación , Quercetina/química , Quercetina/metabolismo , Solubilidad , Tamoxifeno/administración & dosificación , Tamoxifeno/química , Tamoxifeno/metabolismo
8.
Am J Clin Nutr ; 53(6): 1443-9, 1991 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-2035471

RESUMEN

We studied the relationship between eight variables, including age, sex, baseline plasma beta-carotene (BC) concentration, and smoking status and the increase in plasma BC in 582 subjects receiving oral supplementation with 50 mg BC/d. Median plasma BC concentrations after 1 y of supplementation increased from 335 nmol/L at entry to 3163 nmol/L. Changes in plasma BC concentrations ranged widely from -313 to 16,090 nmol/L (median 2721 nmol/L). Multivariate analysis revealed that the subject's plasma BC concentration before supplementation was the most important indicator of the amount of increase after supplementation. Nonsmokers, women, and leaner subjects all had larger increases in plasma concentrations although the statistical model could account for relatively little of the variability in subjects' plasma response to BC supplementation (R2 = 0.14). We conclude that between-subject variability in response to daily supplementation with oral BC is very large and that the best predictor of this response is the initial plasma BC concentration.


Asunto(s)
Carotenoides/sangre , Fumar/metabolismo , Administración Oral , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Constitución Corporal , Peso Corporal , Carotenoides/administración & dosificación , Carotenoides/uso terapéutico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Análisis de Regresión , Factores Sexuales , Neoplasias Cutáneas/prevención & control , beta Caroteno
9.
Am J Clin Nutr ; 66(2): 315-9, 1997 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-9250109

RESUMEN

beta-Carotene has been studied widely as a potential cancer-preventing agent. Recent studies found that subjects who took beta-carotene supplements orally had increases in their serum concentrations of alpha-carotene and lycopene that were large (> 150% increase) and significantly greater than such increases in subjects who received placebo and that similar supplementation was associated with a decrease of approximately 37% in plasma lutein concentrations. A biologic interaction between beta-carotene and other carotenoids was suggested. We measured concentrations of retinol, alpha-tocopherol, and five carotenoids in serum specimens from a random sample of subjects enrolled in a clinical trial of the use of antioxidant vitamins in preventing colonic adenomas. We used serum specimens obtained at enrollment and after the subjects took placebo (n = 54) or 25 mg beta-carotene/d (n = 54) orally for 4 y. In a multivariate analysis, baseline serum concentrations of the analytes, sex, body mass index, diet, smoking status, and age were associated with variable changes in some analytes over the 4-y period but supplementation with beta-carotene was related only to a mean increase in serum beta-carotene itself of 151%. We excluded with 95% confidence an increase in lycopene > 4.9%, an increase in alpha-carotene > 17.6%, and a decrease in lutein > 14.7% in subjects given beta-carotene. These results confirm previous findings that supplementation with beta-carotene given orally does not alter serum concentrations of retinol or alpha-tocopherol. The findings also indicate that beta-carotene supplementation, which results in a moderate increase in serum beta-carotene concentration, does not significantly change serum concentrations of other carotenoids.


Asunto(s)
Carotenoides/sangre , Vitamina A/sangre , Vitamina E/sangre , beta Caroteno/administración & dosificación , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Placebos
10.
Cancer Epidemiol Biomarkers Prev ; 7(9): 783-9, 1998 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9752986

RESUMEN

We evaluated menstrual factors in relation to breast cancer risk in a large, population-based, case-control study. Case women were ascertained through state-wide registries covering Wisconsin, Western Massachusetts, Maine, and New Hampshire; control women were randomly selected from driver's license and Medicare lists in each state. Information regarding menstrual characteristics was obtained through a telephone interview. The study population comprised 6888 breast cancer cases and 9529 control women. Because exogenous hormones influence menstrual cycle patterns, we repeated our analyses in a subgroup of women who had never used oral contraceptives or hormone replacement therapy. Our results indicate decreased breast cancer risk with menarcheal age of 15 years or more, relative to menarche at age 13; the relation was stronger among premenopausal [odds ratio (OR), 0.72; 95% confidence interval (CI), 0.57-0.91] as opposed to postmenopausal women (OR, 0.90; 95% CI, 0.80-1.03). Risk was slightly reduced among premenopausal women whose menstrual cycles did not become regular until at least 5 years after onset of menses, relative to those whose cycles became regular within 1 year (OR, 0.80; 95% CI, 0.63-1.02). There was no clear relation between breast cancer risk and irregular menstrual cycles, episodes of amenorrhea, or menstrual cycle length. Early menopause, whether natural or surgical, was associated with decreased breast cancer risk; surgical menopause before age 40 conferred the strongest protective effect (OR, 0.57; 95% CI, 0.47-0.71). We found no evidence of increased risk with late natural menopause (OR, 0.92; 95% CI, 0.80-1.06). Results in the subgroup of women who never used exogenous hormones were similar to those for the entire group.


Asunto(s)
Neoplasias de la Mama/etiología , Ciclo Menstrual , Adulto , Factores de Edad , Anciano , Neoplasias de la Mama/inducido químicamente , Neoplasias de la Mama/epidemiología , Estudios de Casos y Controles , Anticonceptivos Orales/efectos adversos , Anticonceptivos Orales/farmacología , Femenino , Terapia de Reemplazo de Hormonas/efectos adversos , Hormonas/fisiología , Humanos , Menopausia/efectos de los fármacos , Ciclo Menstrual/efectos de los fármacos , Persona de Mediana Edad , Factores de Riesgo
11.
Cancer Epidemiol Biomarkers Prev ; 7(3): 207-10, 1998 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9521434

RESUMEN

We conducted a case-control study to identify factors associated with the presence of clinically atypical nevi. Potential participants were selected, using a two-staged sampling scheme, from a population-based cohort of 50,000 Swedish women who had responded to a previous health survey questionnaire. Of 500 women sampled for study recruitment, 400 (80%) agreed to participate. Study participants underwent a physician-conducted skin examination, which identified 130 women who had at least one clinically atypical nevus (cases) and 270 women without these lesions (controls). The physician-conducted skin examination also assessed women for benign nevus counts; other risk factor information was based upon responses to a health survey questionnaire. We found a strong and highly statistically significant relationship between number of benign nevi and the presence of at least one clinically atypical nevus (P < 0.0001). Women with 100 or more benign nevi had a 26-fold increased likelihood of having an atypical nevus. We noted statistically significant interactions between number of benign nevi and other factors of interest; thus, the results are reported separately for women with low (<50) or high (> or =50) counts of benign nevi. Among women with low counts of benign nevi, the likelihood of having an atypical nevus increased with degree of freckling; there was also a suggested role for early sun exposure. Among women with high counts of benign nevi, difficulty tanning and lack of peeling sunburns between ages 10 and 19 appeared to increase the likelihood of case status; our data also suggested an inverse relationship between parity and atypical nevi in this subgroup.


Asunto(s)
Neoplasias Inducidas por Radiación/etiología , Nevo Pigmentado/etiología , Nevo/etiología , Lesiones Precancerosas/etiología , Neoplasias Cutáneas/etiología , Adulto , Relación Dosis-Respuesta en la Radiación , Femenino , Humanos , Masculino , Melanosis/etiología , Persona de Mediana Edad , Factores de Riesgo
12.
Cancer Epidemiol Biomarkers Prev ; 7(4): 291-5, 1998 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-9568783

RESUMEN

The association between calcium intake and the risk of colorectal neoplasia remains controversial. This analysis prospectively investigated the association between dietary and supplemental calcium intake and recurrent colorectal adenomas. Participants were part of a multicenter, randomized clinical trial of antioxidant vitamins. The study endpoints were adenomas detected between surveillance colonoscopies conducted at approximately 1 year and 4 years after study entry. Baseline intake of energy-adjusted calcium derived from a food frequency questionnaire was used as the main exposure of interest. Calcium supplement use was assessed by semiannual questionnaires. Logistic regression was used to compute odds ratios and 95% confidence limits, and Poisson regression was used to estimate rate ratios. Subjects in the fifth quintile of dietary calcium had an adjusted odds ratio of 0.72 (95% confidence interval, 0.43-1.22) compared to those in the lowest quintile. Investigation of the numbers of adenomas yielded stronger findings: the rate ratio for the fifth quintile versus the first was 0.63 (95% confidence interval, 0.39-1.02). Dietary calcium seemed to have a greater effect among individuals with a high-fat diet than among those with a low-fat diet; however, the interaction was not statistically significant. Use of calcium supplements was not related to adenoma recurrence. These results suggest that a high calcium intake may be associated with a reduction in risk of recurrent adenomas, especially among individuals on a high-fat diet.


Asunto(s)
Adenoma/prevención & control , Calcio/administración & dosificación , Calcio/metabolismo , Neoplasias Colorrectales/prevención & control , Dieta , Suplementos Dietéticos , Recurrencia Local de Neoplasia/prevención & control , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos
13.
J Clin Epidemiol ; 44(6): 505-12, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-1645398

RESUMEN

We investigated differences in lung cancer care and outcome between academic and community settings for all lung cancer patients diagnosed during 1973-1976 in New Hampshire and Vermont. Trained abstracters reviewed hospital charts to record personal, diagnostic, and clinical information, and survival was determined for all patients through the end of 1979. Patients diagnosed in university hospital cancer centers underwent more staging procedures and tended to be assigned to a higher stage than similar patients diagnosed in community hospitals. When tumor stage was considered as a covariable in a survival analysis, these patients appeared to have a lower mortality rate both for non-small cell tumors (mortality rate ratio, 95% confidence interval = 0.81, 0.71-0.91) and for small cell tumors (0.71, 0.55-0.91). When functional status rather than tumor stage was used to adjust for disease severity, there was no apparent survival advantage for university patients with non-small cell cancer (0.96, 0.85-1.09) and the lower mortality for small cell cancers (0.76, 0.59-0.97) was attenuated, although still statistically significant. We conclude that inconsistently-collected data on clinical stage can complicate comparisons of prognosis between cancer patients from different types of hospitals and that measures of performance status may be more useful indicators of disease severity in population based studies.


Asunto(s)
Centros Médicos Académicos , Hospitales Comunitarios , Neoplasias Pulmonares/mortalidad , Estadificación de Neoplasias/métodos , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Carcinoma de Células Pequeñas/mortalidad , Recolección de Datos/métodos , Métodos Epidemiológicos , Neoplasias Pulmonares/patología , Pronóstico , Análisis de Supervivencia
14.
Chest ; 96(4): 877-84, 1989 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-2791687

RESUMEN

In this study, 82 patients who experienced translaryngeal intubation (TLI) for more than four days were prospectively evaluated for laryngeal complications. At the time of extubation or tracheostomy, direct laryngoscopy was performed in these patients and laryngeal damage evaluated. A typical pattern of laryngeal damage was seen, consisting of mucosal ulcerations along the posterior-medial aspects of both vocal cords and varying degrees of laryngeal edema in 77 patients (94 percent). Performance of a tracheostomy and presence of neuromotor activity were associated with the severity of laryngeal damage, but duration of TLI was not. Laryngoscopy was repeated at two-week intervals in 54 patients and laryngeal damage was resolved within four weeks in 63 percent. These 54 patients were evaluated for adverse clinical effects arising from TLI-induced laryngeal pathology and no relationship was found between laryngeal pathology seen at initial laryngoscopy and the development of adverse effects.


Asunto(s)
Intubación Intratraqueal/efectos adversos , Enfermedades de la Laringe/etiología , Edema Laríngeo/etiología , Ronquera/etiología , Humanos , Mucosa Laríngea/lesiones , Laringoscopía , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Factores de Tiempo , Úlcera/etiología , Pliegues Vocales/lesiones
15.
Radiat Res ; 118(1): 112-30, 1989 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-2704784

RESUMEN

The effects of low-dose-rate irradiation (brachytherapy) were investigated in vivo using a murine mammary adenocarcinoma (MTG-B) growing in the flank of C3H mice. For local tumor irradiations, a noninvasive cap was devised to cover the tumor and house three 125I seeds (average apparent activity 5.2 mCi each) located at 120 degree intervals around the circumference of the hemispherical cap (13 mm i.d.). Mice were secured during treatment in a tube allowing limited mobility while restricting access to the seeds. Tumors were exposed to a series of dose rates ranging from 14-40 cGy/h, and the total dose over the treatment interval (48 or 72 h) ranged from 830 to 2378 cGy. A total of nine experiments were conducted using the caps over a 10-week interval. In each experiment three groups (irradiated tumors, sham controls, and untreated controls) were analyzed, each containing 8-15 mice (N = 34, untreated control; N = 46, sham control; N = 91, brachytherapy irradiation). The brachytherapy results are compared to the effects of external beam irradiation in the same tumor system. A linear relationship was observed between the total radiation dose and doubling volume growth delay (GDDV) or treatment volume growth delay (GDTV) for the brachytherapy and external beam irradiation. The slopes of the dose-response curves are steeper for the acute dose (517 cGy/min) external beam irradiation (0.0072 day/cGy, GDDV; 0.00695 day/cGy, GDTV) than for the brachytherapy (0.0050 day/cGy, GDDV; 0.0057 day/cGy, GDTV) using both GDTV and GDDV end points. Comparison of the tumor volume regrowth slopes indicates that the tumor bed effect is larger for external beam irradiation than for brachytherapy, suggesting that the tumor bed effect may be dose-rate dependent.


Asunto(s)
Adenocarcinoma/radioterapia , Braquiterapia , Radioisótopos de Yodo/uso terapéutico , Neoplasias Mamarias Experimentales/radioterapia , Animales , Femenino , Ratones , Ratones Endogámicos C3H , Trasplante de Neoplasias
16.
Ann Thorac Surg ; 63(1): 193-7, 1997 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8993264

RESUMEN

BACKGROUND: Early detection and surgical resection offers the highest likelihood of cure for patients with lung cancer. Patients presenting at the extremes of age may fail to benefit maximally from these interventions. To study the impact of age on stage, histology, symptom, and treatment of patients with non-small cell lung cancer, we undertook a retrospective review. METHODS: One thousand eight hundred two patients with non-small cell lung cancer were identified between 1983 and 1993. Patients were selected by age as less than 45 years (55 patients) and 80 years or more (108 patients), and their medical records were reviewed. RESULTS: Three younger patients (6%) presented with stage I or II disease, yet 15 (32%) underwent thoracic operation. Twenty-seven elderly patients (33%) presented with early stage disease and only 6% underwent operation. The median survival was significantly longer for the younger population with surgically resectable stages of disease (stage I to IIIA) (p < 0.05), whereas no significant difference in survival was seen for the two groups with advanced disease (stage IIIB and IV). CONCLUSIONS: Age significantly affects the presentation and treatment of non-small cell lung cancer patients. Although thoracic operation imparts the greatest survival advantage, this benefit is diminished due to advanced disease in the younger patients and lack of surgical intervention in the elderly.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/diagnóstico , Carcinoma de Pulmón de Células no Pequeñas/cirugía , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/cirugía , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Estudios de Casos y Controles , Femenino , Humanos , Neoplasias Pulmonares/mortalidad , Masculino , Estadificación de Neoplasias , Sistema de Registros , Estudios Retrospectivos , Análisis de Supervivencia , Tasa de Supervivencia , Resultado del Tratamiento
17.
Clin Ther ; 20(3): 497-504, 1998.
Artículo en Inglés | MEDLINE | ID: mdl-9663365

RESUMEN

Acarbose is an alpha-glucosidase inhibitor approved for the treatment of type 2 diabetes mellitus. Acarbose inhibits carbohydrate digestion, allowing an excessive amount of undigested carbohydrate to reach the colon. Bacterial fermentation of the carbohydrate produces intestinal gas, which can cause flatulence and abdominal pain. Beano, an over-the-counter enzyme preparation (alpha-galactosidase), diminishes intestinal gas production by enhancing the breakdown of certain carbohydrates before they reach the lower intestine. This study was undertaken to investigate whether concomitant administration of Beano and acarbose could reduce the flatulence associated with acarbose and, if so, whether Beano would interfere with the effects of acarbose on postprandial serum glucose concentration. In this randomized, double-masked, placebo-controlled, three-period crossover study, 37 patients with type 2 diabetes mellitus received acarbose 100 mg, acarbose 100 mg plus Beano, or placebo. The study population consisted of 20 males and 17 females who ranged in age from 36 to 72 years (mean, 56 years) and in weight from 62 to 142 kg (mean, 92 kg). Each treatment period consisted of 3 days, during which both acarbose and Beano were given at the beginning of each of three meals. There was a 4-day washout interval between each treatment period. The frequency and severity of flatulence were measured using a score compiled from patient diaries. As an additional measure of intestinal gas production, breath hydrogen concentration was measured on day 3 of each treatment period. Postprandial serum glucose concentration was measured at predetermined times after each morning dose to assess pharmacodynamic activity. Patients who took Beano with acarbose had a significantly lower flatulence score than did those who took acarbose alone (0.79 vs 1.09). Consistent with this finding, breath hydrogen concentration was lower after administration of acarbose plus Beano than with acarbose alone (31.2 ppm vs 50.5 ppm). Beano had variable effects on the ability of acarbose to reduce the postprandial serum glucose concentration. Although postprandial serum glucose levels were higher in patients who received acarbose plus Beano than in those who received acarbose alone, both treatments (with or without Beano) resulted in postprandial serum glucose levels that were significantly lower than those seen with placebo. Therefore, although Beano appeared to diminish the activity of acarbose, postprandial serum glucose concentrations still decreased significantly in patients taking Beano with acarbose. Beano has been shown to alleviate the flatulence accompanying acarbose treatment, but it may also interfere with the glucose-lowering effect of acarbose.


Asunto(s)
Inhibidores Enzimáticos/efectos adversos , Inhibidores Enzimáticos/farmacocinética , Inhibidores de Glicósido Hidrolasas , Hipoglucemiantes/efectos adversos , Hipoglucemiantes/farmacocinética , Trisacáridos/efectos adversos , Trisacáridos/farmacocinética , alfa-Galactosidasa/uso terapéutico , Acarbosa , Adulto , Anciano , Glucemia/metabolismo , Pruebas Respiratorias , Estudios Cruzados , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Método Doble Ciego , Inhibidores Enzimáticos/uso terapéutico , Femenino , Humanos , Hidrógeno/metabolismo , Hipoglucemiantes/uso terapéutico , Masculino , Persona de Mediana Edad , Trisacáridos/uso terapéutico , alfa-Galactosidasa/efectos adversos
18.
J Consult Clin Psychol ; 68(2): 258-68, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10780126

RESUMEN

Current posttraumatic stress disorder (PTSD) associated with participation in secret military tests of mustard gas during World War II was assessed in 363 male military veterans who were randomly sampled from a registry developed by the Department of Veterans Affairs. Current prevalence was 32% for full PTSD and 10% for partial PTSD. Prevalence of PTSD varied as a function of risk and protective factors, including volunteering, physical symptoms during the tests, and prohibited disclosure. Prediction of partial PTSD was weaker than prediction of full PTSD. Veterans with full PTSD reported poorer physical health, a higher likelihood of several chronic illnesses and health-related disability, greater functional impairment, and higher likelihood of health care use than those with no PTSD. Veterans with partial PTSD also had poorer outcomes than did veterans with no PTSD in a subset of these domains. There is discussion of the traumatic elements of experimental mustard gas exposure, vulnerability to PTSD, and the relevance of these findings to understanding the broad range of outcomes associated with PTSD.


Asunto(s)
Guerra Química/psicología , Trastornos de Combate/psicología , Intoxicación por Gas/psicología , Gas Mostaza/efectos adversos , Veteranos/psicología , Anciano , Trastornos de Combate/diagnóstico , Evaluación de la Discapacidad , Evaluación Geriátrica , Humanos , Masculino , Rol del Enfermo
19.
J Pain Symptom Manage ; 18(3): 157-63, 1999 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10517036

RESUMEN

The purpose of the current study was to examine the impact of massage therapy on psychological, physical, and psychophysiological measures in patients undergoing autologous bone marrow transplantation (BMT). Patients scheduled to undergo BMT were randomly assigned to receive either (a) massage therapy, consisting of 20-minute sessions of shoulder, neck, head, and facial massage, or (b) standard treatment. Overall effects of massage therapy on anxiety, depression, and mood were assessed pretreatment, midtreatment, and prior to discharge using the State-Trait Anxiety Inventory, Beck Depression Inventory, and Brief Profile of Mood States, respectively. The immediate effects of massage were measured via the State Anxiety Inventory, Numerical Scales of Distress, Fatigue, Nausea, and Pain and indices of psychophysiological arousal (heart rate, blood pressure, and respiration rate), collected prior to and following patients' first, fifth, and final massage (on Days--7, midtreatment, and predischarge). Analysis of the data evaluating the immediate effects of massage showed that patients in the massage therapy group demonstrated significantly larger reductions in distress, fatigue, nausea, and State Anxiety than the standard treatment group at Day-7, in State Anxiety at midtreatment, and in fatigue at the predischarge assessment. The overall measures of psychological symptoms measured at pretreatment, midtreatment, and prior to discharge showed no overall group differences, although the massage group scored significantly lower on the State Anxiety Inventory than the standard care group at the midtreatment assessment. The two groups together showed significant declines through time on scores from the Profile of Mood States and State and Trait Anxiety Inventories.


Asunto(s)
Trasplante de Médula Ósea/efectos adversos , Masaje , Estrés Psicológico/terapia , Adulto , Afecto , Femenino , Humanos , Masculino , Escalas de Valoración Psiquiátrica , Estrés Psicológico/etiología , Estrés Psicológico/psicología
20.
J Reprod Med ; 43(10): 889-92, 1998 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9800672

RESUMEN

OBJECTIVE: To compare the Pipelle suction curette with the Vabra aspirating catheter in terms of their ability to obtain a sufficient amount of tissue (> or = 1 mm2 of endometrium) in order to make a histologic diagnosis. STUDY DESIGN: A prospective, randomized, double-blind, crossover study at Dartmouth-Hitchcock Medical Center, which serves as the clinical staff of the Dartmouth Medical School. RESULTS: Agreement between the Pipelle and Vabra was high: 74 of 79 (93.7%) samples. The Pipelle obtained adequate samples in 78 of 79 (98.7%) cases as compared with 75 of 79 (94.9%) for the Vabra. The McNemar test comparing these two proportions, adjusting for the fact that the Pipelle and Vabra readings were taken on the same subjects at the same visits, yielded a nonsignificant result (P = .180). CONCLUSION: The Pipelle and Vabra have equal diagnostic accuracy.


Asunto(s)
Biopsia/métodos , Dilatación y Legrado Uterino/métodos , Endometrio/patología , Método Doble Ciego , Femenino , Humanos , Inhalación , Estudios Prospectivos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
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