RESUMO
The year 1860 was a beginning of social, political, and medical upheaval in the United States. The Civil War over states' rights, which would last for 4 years and change the political landscape of the United States forever, had its roots in that year. American neurology was conceived and gestated by the Civil War because of the collaboration between William A. Hammond (1828-1900) and Silas Weir Mitchell (1829-1914), who became the founders of American neurology. Thus, 1860 serves as a pivotal point from which to view the precursors of American neurology and the later war and postwar developments.
Assuntos
Neurologia/história , Educação Médica/história , História do Século XIX , Humanos , Neurologia/educação , Estados UnidosRESUMO
OBJECTIVE: To determine the effects of cardiopulmonary bypass and famotidine on gastric acid secretion in adults undergoing cardiac surgery. DESIGN: Prospective, randomized, double-blind, placebo-controlled study. SETTING: University teaching hospital. PARTICIPANTS: Eighteen patients undergoing elective cardiac surgery with cardiopulmonary bypass. MAIN OUTCOME MEASURES: Famotidine 20 mg or NaCl 0.9% placebo was administered intravenously following induction of anesthesia and placement of a nasogastric pH probe. A second dose was given 12 hours after surgery in the intensive care unit. Gastric pH was measured continuously and gastric volume was measured every 4 hours for up to 24 hours after cardiopulmonary bypass. RESULTS: Following famotidine administration, pH increased by 43% within 45 minutes and remained above 5.5 throughout the study period (p < 0.05 vs placebo and baseline). The gastric pH did not increase, but remained above 4.0 in most patients in the placebo group for up to 12 hours after cardiopulmonary bypass. Gastric volumes were on average 24% lower in the famotidine group (p > 0.05). CONCLUSIONS: Gastric acid secretion is decreased during and for 12 hours after cardiopulmonary bypass. Perioperative administration of famotidine suppresses gastric secretion in cardiac surgery patients.
Assuntos
Procedimentos Cirúrgicos Cardíacos , Famotidina/farmacologia , Ácido Gástrico/metabolismo , Adulto , Idoso , Ponte Cardiopulmonar , Método Duplo-Cego , Feminino , Mucosa Gástrica/efeitos dos fármacos , Mucosa Gástrica/metabolismo , Hospitais de Ensino , Humanos , Injeções Intravenosas , Masculino , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
STUDY OBJECTIVE: To determine the hemodynamic effects of famotidine in patients undergoing cardiac surgery. DESIGN: A prospective, randomized, double-blinded, placebo-controlled study. SETTING: A large university teaching hospital. PATIENTS: Twenty-one patients undergoing elective cardiac surgery with cardiopulmonary bypass. INTERVENTIONS: The patients received a rapid intravenous bolus injection of famotidine 20 mg or saline placebo after anesthesia induction. A second dose was given 12 hours after surgery in the intensive care unit. MEASUREMENTS AND MAIN RESULTS: Serial hemodynamic measurements (heart rate, arterial blood pressure, cardiac index, pulmonary arterial pressure, central venous pressure, systemic vascular resistance) were obtained after each famotidine or placebo dose and analyzed by ANOVA: The values were not altered (p > 0.05) after intraoperative or postoperative famotidine or placebo administration. CONCLUSIONS: Rapid intravenous bolus administration of famotidine does not alter patient hemodynamics after anesthesia induction or in the intensive care unit after cardiac surgery.
Assuntos
Procedimentos Cirúrgicos Cardíacos , Famotidina/farmacologia , Hemodinâmica/efeitos dos fármacos , Idoso , Anestesia , Pressão Sanguínea/efeitos dos fármacos , Ponte Cardiopulmonar , Método Duplo-Cego , Famotidina/administração & dosagem , Feminino , Frequência Cardíaca/efeitos dos fármacos , Hospitais Universitários , Humanos , Injeções Intravenosas , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Estudos Prospectivos , Pressão Propulsora Pulmonar/efeitos dos fármacos , Pressão Venosa/efeitos dos fármacosRESUMO
The purpose of this study was to determine the effect of material and design on the force and stress required to permanently deform metal brackets. Fourteen types of metal brackets were categorized according to raw material composition, slot torque degree, and wing type. Five types of raw materials, three types of slot torque degree, and four types of wing design were tested using an archwire torque test developed by Flores. An analysis of variance (ANOVA) and t-test showed that all three categories had a significant effect on the force and stress needed to permanently deform metal brackets. Of the three, raw material had the greatest effect on the amount of force. Results showed that 17-4PH and 303S had higher yield strengths and regular twin brackets had higher resistance to deformation. Also, as slot torque degree increased, brackets deformed with less force. Result confirmed that brackets requiring the greatest stress to permanently deform were made of steel with the greatest hardness.
Assuntos
Ligas Dentárias/química , Desenho de Aparelho Ortodôntico , Braquetes Ortodônticos , Análise de Variância , Dureza , Teste de Materiais , Fios Ortodônticos , Rotação , Aço Inoxidável/química , Estresse Mecânico , Propriedades de Superfície , Resistência à TraçãoRESUMO
We studied low-dose intramuscular succinylcholine in 9 subjects as part as an ongoing investigation of its potential to predict responses to botulinum toxin. We measured compound muscle action potentials (CMAPs) from the extensor digitorum brevis (EDB) muscles in each foot before and after intramuscular injections of 2.5 mg of succinylcholine into the EDB. Succinylcholine reduced mean CMAP amplitudes to 42% of baseline; the maximal reduction occurred at 19 +/- 6 (mean +/- standard deviation) minutes. Recovery to 73% of the baseline CMAP amplitude (approximately 50% recovery from block) occurred at 105 +/- 49 minutes after injection. Repetitive (train-of-four) stimulation at 2 Hz produced mild CMAP decrements (5-25%), but only during the recovery phase. Varying the succinylcholine concentrations (10, 20, or 50 mg/mL) while holding the total drug dose constant did not change the rate of onset or the extent of block. No systemic complications occurred. We conclude that: (1) 2.5 mg intramuscular succinylcholine can safely induce selective muscle weakness with a time course that differs from intravenously administered succinylcholine; and (2) further clinical studies comparing intramuscular succinylcholine and botulinum toxin are warranted.
Assuntos
Pé/fisiologia , Músculos/fisiologia , Succinilcolina/administração & dosagem , Potenciais de Ação , Adulto , Estimulação Elétrica , Feminino , Humanos , Injeções Intramusculares , Masculino , Músculos/efeitos dos fármacos , Succinilcolina/farmacologiaRESUMO
White Carneau pigeons have previously been shown to be genetically susceptible to the development of spontaneous atherogenesis. The severity of development of atheromatous lesions is considerably greater than a more resistant breed of Show Racer pigeons. Analysis of levels of total hydroxyproline and isodesmosine in the thoracic aorta and celiac bifurcation of prelesion, six-week-old White Carneau and Show Racer pigeons, revealed an increased accumulation of total collagen and cross-linked elastin in the White Carneau arterial tissue. Using dot blot hybridization, measurements of steady state levels of several mRNAs in total RNA extracted from pigeon aortic tissue were also determined. While the increased deposition of extracellular matrix proteins was paralleled by a significantly greater recovery of mRNAs coding for pro alpha 1(1) collagen and elastin, in RNA extracted from White Carneau aortal tissue, increased recovery of mRNAs coding for an intracellular protein, gamma-actin were also observed in White Carneau aortal tissue. No differences in steady state levels of mRNAs coding for pro alpha 1(1) collagen and elastin were observed in RNA extracted from pigeon liver, suggesting a tissue specific increase in the mRNAs coding for these connective tissue proteins in aorta. A markedly reduced cell population however, was responsible for this overall increase in biosynthetic activity in White Carneau pigeon aortic tissue. This was demonstrated by a reduced cell count and by the recovery of reduced levels of total DNA in the thoracic aorta and celiac bifurcation of the White Carneau pigeon. The cell population in White Carneau aortic tissue exhibits therefore a markedly different phenotype with respect to a capacity for the biosynthesis of extracellular and intracellular proteins.
Assuntos
Aorta Torácica/metabolismo , Arteriosclerose/veterinária , Columbidae , Proteínas da Matriz Extracelular/metabolismo , Actinas/genética , Actinas/metabolismo , Animais , Aorta Torácica/patologia , Arteriosclerose/genética , Arteriosclerose/metabolismo , Arteriosclerose/patologia , Artéria Celíaca/metabolismo , Colágeno/genética , Colágeno/metabolismo , DNA/metabolismo , Elastina/genética , Elastina/metabolismo , Hibridização de Ácido Nucleico , Fenótipo , RNA Mensageiro/metabolismoRESUMO
Recent demand for esthetic brackets has led to the development and use of ceramic brackets in orthodontics. The purpose of this study was to compare the fracture strength of different ceramic brackets under different surface conditions and ligation methods using a torsional wire bending force. Five different bracket types (two polycrystalline, two single-crystal, and one metal) were tested using elastic and wire ligation, with half being scratched and the other half remaining unscratched. Results showed a significant difference between bracket types and surface conditions. Non-scratched single-crystal brackets had higher fracture strengths and slightly higher fracture loads than polycrystalline brackets. However, single-crystal brackets were significantly adversely affected by surface damage (scratching), while polycrystalline brackets were not significantly affected by surface damage. The fracture behavior of ceramic brackets followed the Griffith model where fracture strength decreased following surface damage.
Assuntos
Cerâmica/química , Colagem Dentária , Aparelhos Ortodônticos , Análise de Variância , Ligas Dentárias/química , Análise do Estresse Dentário , Elasticidade , Fios Ortodônticos , Borracha/química , Estresse Mecânico , Propriedades de Superfície , Resistência à TraçãoRESUMO
A genome rearrangement involving RNA segment 11 of a bovine rotavirus has been analysed by molecular cloning and sequencing. This revealed that the rearranged genome segment was generated by a head to tail concatemerisation of two almost full length copies of segment 11. The upstream copy of the gene has lost its 3' end and the downstream copy its 5' end. The truncation of the upstream copy of the gene occurs within the termination codon for VP11 converting it from a UAG to a UGA, the rearranged gene is therefore still able to encode a normal VP11. The possible mechanisms by which this rearrangement may have been generated are discussed.
Assuntos
Rearranjo Gênico , Genes Virais , Rotavirus/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Bovinos , Linhagem Celular , Mapeamento Cromossômico , Clonagem Molecular , Dados de Sequência Molecular , RNA de Cadeia Dupla/genética , Rotavirus/isolamento & purificaçãoRESUMO
Gastrointestinal (GI) complications after cardiac surgical procedures are infrequent but severe. Thirty-three GI complications were identified in 25 patients who underwent cardiac surgery during a 7-year period (2.0% incidence). The mortality rate for patients having these GI complications was 44%. Acute acalculous cholecystitis was the most lethal complication (86%). Acute pancreatitis was the most common complication (eight patients). Most patients responded well to conservative measures. Five patients had upper GI hemorrhage and three had lower GI bleeding that required more than 2 U of packed red blood cells. All patient conditions were diagnosed endoscopically and none necessitated operation. Of the remaining patients, one was operated on because of perforated duodenal ulcer, one because of perforated diverticulitis, and one because of pseudo-obstruction of the colon, and one patient underwent diagnostic laparotomy and showed negative results for presumed acalculous cholecystitis. Liver failure was fatal in all three patients in whom it occurred. GI complications correlated significantly with advanced age, prolonged bypass times, valve surgery, and the female sex. We conclude that septic GI complications--particularly acute acalculous cholecystitis and perforated viscus--after cardiac surgery are uncommon but lethal. Clinical features are often subtle, and a high index of suspicion is necessary for an early diagnosis and the institution of appropriate treatment.
Assuntos
Ponte Cardiopulmonar/efeitos adversos , Gastroenteropatias/etiologia , Doença Aguda , Adulto , Idoso , Colecistite/etiologia , Feminino , Gastroenteropatias/mortalidade , Gastroenteropatias/terapia , Hemorragia Gastrointestinal/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Pancreatite/etiologia , Fatores de RiscoRESUMO
Quantitative levels of mRNAs coding for elastin, types I and III procollagen and gamma-actin were measured in porcine vascular material following balloon catheterization. A balloon catheter was introduced into the thoracic aorta and jugular vein of 3-6 week old pigs; following distention and six days of postoperative recovery, tissue samples were obtained for histopathology, electron microscopy, RNA extraction and mRNA quantitation. Using a series of mammalian cDNA clones and the procedure of slot blot hybridization, we have shown that elastin and types I and III procollagen mRNA levels rose significantly during the postoperative period following vascular distention. The increase correlated with an increase in the cell mass present in both the venous and arterial intimal layers. Changes in gamma-actin mRNA levels were also associated with this rapid proliferative response but in arterial tissue only.
Assuntos
Elastina/biossíntese , Endotélio Vascular/metabolismo , RNA Mensageiro/metabolismo , Actinas/biossíntese , Animais , Northern Blotting , DNA/metabolismo , Endotélio Vascular/patologia , Hiperplasia/metabolismo , Hiperplasia/patologia , Pró-Colágeno/biossíntese , Estresse Mecânico , SuínosRESUMO
The mechanical properties of ceramic brackets, particularly fracture toughness, are so different from those of metal brackets that their selection and handling requires a completely different set of criteria and techniques.
Assuntos
Cerâmica , Teste de Materiais , Aparelhos Ortodônticos , Estresse Mecânico , Propriedades de Superfície , Resistência à TraçãoRESUMO
The Jahnke-Barron heart support has proven to be a useful adjunct to coronary artery surgery by allowing an easy access to the coronary arteries while maintaining a quiet operating field. Further, the use of this device eliminates the need for a surgical assistant or a heart holder.
Assuntos
Ponte de Artéria Coronária/instrumentação , Telas Cirúrgicas , Vasos Coronários/cirurgia , Desenho de Equipamento , Humanos , Propriedades de SuperfícieRESUMO
Three cardiac surgical patients with acute postoperative renal failure were treated with a constant infusion of furosemide (Lasix) after furosemide given in bolus proved ineffective. Furosemide given continuously brought about a prompt resolution of the oliguria and tended to hasten the resolution of acute renal failure.
Assuntos
Injúria Renal Aguda/tratamento farmacológico , Furosemida/administração & dosagem , Complicações Pós-Operatórias/tratamento farmacológico , Micção/efeitos dos fármacos , Injúria Renal Aguda/etiologia , Idoso , Feminino , Furosemida/uso terapêutico , Humanos , Infusões Parenterais , Masculino , Pessoa de Meia-IdadeAssuntos
Dissulfiram/uso terapêutico , Solventes/efeitos adversos , Adulto , Alcoolismo/reabilitação , Feminino , Humanos , MasculinoRESUMO
Over 100 synaptic ribbons were studied in the intact animal from birth to the 23rd day and over 500 were studied in the isolated organ up to 24 days in culture. Our findings suggest that synaptogenesis in the cochlea of the mouse occurs mainly postnatally and lasts at least 14 days. Afferent synapses of young cochleas are characterized by round ribbons which are attached to the presynaptic membrane by two rodlets, each surrounded by a discrete triangular density. The postsynaptic density is continuous and coextends with the presynaptic complex. The single layer of vesicles surrounding the dense body of the ribbon is disrupted by the presynaptic densities. In an afferent synapse of the adolescent animal, the predominant organelle is a plate ribbon--often laminated--which measures on the average approximately 1000 A wide, 2000 A tall, and 1500 A long (one section = 700 A). The ribbon is attached to a presynaptic density, arcuate in form; a row of synaptic vesicles is aligned along each side of the arcuate density. The presynaptic membrane forms a trough accommodating the ribbon. The postsynaptic density exceeds the territory of the ribbon. Similar development of the synapse also may be observed in culture. Structural variability of ribbons (seen especially in culture), clustering of ribbons, multiribbon synapses, and ribbon families seem to be characteristic of early development. The occurrence of ring-like or fenestrated ribbons in the intact adolescent animal suggests a limited life span of the organelle. A decrease in the ribbon population of the outer hair cells, to about 20% of the total number, occurs postnatally in the intact animal. A similar decrease occurs also in culture. This implies that the ribbon population is not affected by the efferent influx. The mature cochlear ribbon appears comparable to those of the retina and some ampullary organs of electric fishes.
Assuntos
Órgão Espiral/crescimento & desenvolvimento , Sinapses/fisiologia , Vias Aferentes/fisiologia , Envelhecimento , Animais , Cóclea/crescimento & desenvolvimento , Células Ciliadas Auditivas/crescimento & desenvolvimento , Células Ciliadas Auditivas/fisiologia , Camundongos , Camundongos Endogâmicos , Técnicas de Cultura de ÓrgãosRESUMO
A portable device for the rapid concentration of viruses from natural freshwaters described and its performance in field use is evaluated. The system handled up to 500 litres of water in less than 90 min at a cost of only 2 pounds per sample. Where the samples contained sufficient bacteriophages for detection by direct plating the apparent phage recoveries were greater than 75%. Plant and animal viruses were also concentrated from waters with this system.
Assuntos
Técnicas Microbiológicas/instrumentação , Vírus/isolamento & purificação , Microbiologia da Água , Bacteriófagos/isolamento & purificação , Enterovirus/isolamento & purificação , Água Doce , Vírus de Plantas/isolamento & purificação , Poliovirus/isolamento & purificaçãoRESUMO
A method is described which allows the half saturation tension (T50 value) of blood to be obtained within 5 min on samples of 100 mul volume, using a standard Clark PO2 electrode A PO2-time trace is recorded on a blood/buffer suspension from which the oxygen is removed at a constant rate using yeast cells. The T50 value is then derived graphically. The values taken for 210 traces show the graphical solutions to lie within +/- 0.5 mmHg of the tensions calculated from complete dissociation curves. Values from a further 590 traces show the T50 estimates are also reproducible with a standard error of less than 0.3 mmHg.