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2.
J Surg Res ; 81(2): 209-15, 1999 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9927542

RESUMEN

BACKGROUND: Cardiomyoplasty is a new surgical alternative therapy for CHF. Although conditioning of muscle for cardiomyoplasty has a positive effect on fatigue resistance it also produces negative effects. In this study we assessed the effect of salbutamol, a beta2-agonist, on both the positive and the negative effects of conditioning. METHODS: In a control group of six animals one latissimus dorsi was subject to chronic, 1 Hz, low-frequency stimulation (CLFS) while the other served as a control. The experimental group of seven dogs received a continuous SC infusion of salbutamol and one latissimus dorsi was subjected to CLFS. The other muscle demonstrated the effects of salbutamol per se. After 42 days the animals were anesthetized and fatigue resistance, muscle mass, and mechanical properties of the muscles were evaluated. RESULTS: Salbutamol increased muscle mass, tetanic tension, and rate of rise and fall of tetanic tension. It diminished fatigue resistance and had no effect on shortening velocity. Chronic stimulation decreased muscle mass, tetanic tension, rate of rise and fall of tetanic tension, and muscle shortening velocity in both groups of dogs. Salbutamol diminished the declines in muscle mass, rate of tension development, and rate of muscle shortening due to CLFS, but did not change the effects of CLFS on tetanic tension and the rate of fall of tetanic tension. Salbutamol did not alter the increase in fatigue resistance induced by CLFS. CONCLUSIONS: The favorable effect of CLFS on fatigue resistance was unaffected by salbutamol. The unfavorable effects of CLFS on loss of muscle mass, rate of tension development, and decline in shortening velocity were partially blocked by salbutamol, improving the ability of the latissimus dorsi to augment cardiac systole.


Asunto(s)
Albuterol/farmacología , Cardiomioplastia/métodos , Contracción Muscular/fisiología , Músculo Esquelético/efectos de los fármacos , Ventrículo de Músculo Esquelético/fisiología , Albuterol/administración & dosificación , Animales , Perros , Estimulación Eléctrica , Infusiones Parenterales , Masculino , Contracción Muscular/efectos de los fármacos , Fatiga Muscular , Músculo Esquelético/anatomía & histología , Músculo Esquelético/fisiología , Unión Neuromuscular/efectos de los fármacos , Unión Neuromuscular/fisiología
3.
J Surg Res ; 75(1): 6-17, 1998 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-9614850

RESUMEN

The observations in vivo of a non-linear, afterload-sensitive end-systolic pressure-volume relation (ESPVR) and a linear, load-insensitive preload recruitable stroke work (PRSW) relation may be reconciled by considering the PRSW as a product of both the ventricular ESPVR and the arterial elastance (Ea). We obtained pressure-volume data from eight conscious dogs. The ESPVR was nonlinear, and its trajectory was afterload-dependent. The PRSW was linear and load-independent. Arterial elastance changed with both acute reductions in preload and steady-state changes in afterload. The PRSW relation thus describes both myocardial function and ventricular-arterial interaction and is a useful index of cardiovascular performance in patients.


Asunto(s)
Presión Sanguínea , Corazón/fisiología , Contracción Miocárdica , Volumen Sistólico , Sístole , Animales , Arterias/fisiología , Circulación Coronaria , Perros , Elasticidad , Femenino , Pruebas de Función Cardíaca , Masculino , Función Ventricular
4.
Pflugers Arch ; 435(4): 511-7, 1998 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9446698

RESUMEN

Chronic administration of salbutamol induced expression of hybrid fibers in canine skeletal muscles. Fast-twitch fibers expressed SERCA2a (the slow-twitch isoform of sarcoplasmic reticulum Ca2+-ATPase) and slow-twitch fibers expressed SERCA1 (the fast-twitch isoform of the Ca2+-ATPase). The proportion of fibers that became hybrid increased from a small percentage in the control muscles to 30% in the predominantly fast-twitch latissimus dorsi and to 45% in the predominantly slow-twitch vastus intermedius. In contrast to this response by the SERCA genes the phospholamban gene response was muscle specific. The fraction of fibers that expressed phospholamban decreased slightly in the latissimus dorsi while increasing moderately in the vastus intermedius. The effects of chronic neurostimulation of the latissimus dorsi on SERCA1, SERCA2a and phospholamban levels were mostly blocked by salbutamol. While 100% of fibers from neurostimulated muscles expressed phospholamban, only 51% of the fibers from the neurostimulated and salbutamol-treated muscles expressed it. In the neurostimulated muscle, very few muscle fibers expressed SERCA1a while 61% of the fibers that received salbutamol expressed it, albeit as hybrid fibers. The levels of SERCA2a in response to these interventions were just the opposite. In the neurostimulated muscle 37.5% of fibers were hybrid and 62.5% expressed SERCA2a only. With co-administration of neurostimulation and salbutamol, 61.3% of fibers were hybrid and 38.7% expressed SERCA2a only.


Asunto(s)
Agonistas de Receptores Adrenérgicos alfa 2 , Agonistas Adrenérgicos beta/farmacología , Albuterol/farmacología , Proteínas de Unión al Calcio/biosíntesis , ATPasas Transportadoras de Calcio/biosíntesis , Isoenzimas/biosíntesis , Fibras Musculares de Contracción Rápida/enzimología , Músculo Esquelético/enzimología , Retículo Sarcoplasmático/enzimología , Animales , Perros , Estimulación Eléctrica , Inmunohistoquímica , Fibras Musculares de Contracción Rápida/efectos de los fármacos , Fibras Musculares de Contracción Rápida/ultraestructura , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/ultraestructura , Unión Neuromuscular/efectos de los fármacos , Unión Neuromuscular/fisiología , Retículo Sarcoplasmático/efectos de los fármacos
5.
Biochim Biophys Acta ; 1395(1): 121-5, 1998 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-9434159

RESUMEN

Chronic low frequency stimulation of predominantly fast-twitch skeletal muscles decrease the levels of SERCA1 (fast-twitch sarco(endo)plasmic reticulum Ca2+-ATPase) mRNA, and increase the levels of SERCA2 (slow-twitch sarco(endo)plasmic reticulum Ca2+-ATPase) and phospholamban mRNAs. To assess the role of transcription in these changes in mRNA levels, nuclei were isolated from chronically stimulated canine latissimus dorsi muscles and transcription rates were estimated by nuclear run-on assays. Decreases in the rates of SERCA1 gene transcription matched the fall in its mRNA level and increases in the rates of SERCA2 and phospholamban gene transcription matched the increases in their mRNAs.


Asunto(s)
Proteínas de Unión al Calcio/genética , ATPasas Transportadoras de Calcio/genética , Regulación de la Expresión Génica/fisiología , Fibras Musculares de Contracción Rápida/fisiología , Transcripción Genética/fisiología , Animales , Núcleo Celular , Perros , Retículo Endoplásmico/enzimología , Regulación Enzimológica de la Expresión Génica/fisiología , Genes/genética , Fibras Musculares de Contracción Rápida/química , Músculo Esquelético/química , Músculo Esquelético/fisiología , ARN Mensajero/análisis , Retículo Sarcoplasmático/enzimología
6.
Am J Surg ; 174(2): 177-80, 1997 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-9293839

RESUMEN

BACKGROUND: The patency of vascular reconstructive procedures is limited by the development of intimal hyperplasia (IH). Nitric oxide (NO) seems to be beneficial in abrogating this process. Currently, there is little information concerning inducible nitric oxide synthase (iNOS), the enzyme responsible for NO synthesis, and human vein grafts. The purpose of this study was to examine iNOS gene expression in human aortocoronary vein grafts (ACVG) and infrainguinal vein bypass grafts (IVG). METHODS: Nonthrombosed sections from ACVG (n = 5), IVG (n = 5), and control saphenous vein (SV; n = 4) were harvested and processed for RNA isolation. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed on samples using 32P radioactively end labeled primers. Glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) was the internal control, and results were expressed as iNOS pmol/GAPDH pmol. RESULTS: There was a significant increase in the iNOS gene expression in the ACVG (0.049 +/- 0.01) when compared with IVG (0.019 +/- 0.001) or normal SV (0.011 +/- 0.002; P < or = 0.05). There was no significant difference between normal vein and the infrainguinal grafts. Sequencing of a fragment of the amplified 428 bp gene product confirmed 84% homology with the available gene bank human sequence. CONCLUSIONS: This study proves that iNOS is expressed in human vein bypass grafts. Additionally, there is a significant elevation of iNOS message in human ACVGs compared with IVG or normal SV. This difference may be the result of the unique vascular beds supplied by these grafts. Ultimately, manipulation of iNOS expression may lead to therapies to alleviate IH in these grafts.


Asunto(s)
Puente de Arteria Coronaria , Regulación Enzimológica de la Expresión Génica , Pierna/irrigación sanguínea , Óxido Nítrico Sintasa/biosíntesis , Homología de Secuencia , Venas/enzimología , Venas/trasplante , Arteriopatías Oclusivas/cirugía , Secuencia de Bases , Enfermedad Coronaria/cirugía , Activación Enzimática , Humanos , Datos de Secuencia Molecular , Óxido Nítrico Sintasa/química , Reacción en Cadena de la Polimerasa/métodos , Transcripción Genética
7.
Pflugers Arch ; 434(2): 209-11, 1997 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-9136677

RESUMEN

Canine latissimus dorsi, composed predominantly of fast-twitch muscle fibers, were subjected to chronic 1 Hz neuromuscular stimulation for periods up to 42 days to induce changes in gene expression. This produced down regulation of SERCA1 (fast-twitch isoform of sarco(endo)plasmic reticulum Ca2+-ATPase), a gene product of fast-twitch muscle, and up regulation fo SERCA2 (slow-twitch isoform of sarco(endo)plasmic reticulum Ca2+-ATPase) and phospholamban, products of genes expressed by slow-twitch muscles. To assess the involvement of MyoD and myogenin in the regulation of the expression of these genes their levels were measured during the stimulation period. The prompt, at 7 days, fall in SERCA1 mRNA preceded the fall in MyoD by about 7 days, suggesting that the decline in MyoD was not causally related to the decline in SERCA1. The prompt rise in SERCA2 mRNA at 7 days preceded the rise in myogenin by 14 days. The rise in myogenin at 21 days did correlate with the similar rise in phospholamban mRNA.


Asunto(s)
Proteínas de Unión al Calcio/metabolismo , Fibras Musculares de Contracción Rápida/metabolismo , Fibras Musculares de Contracción Lenta/metabolismo , Proteínas Musculares/metabolismo , Músculo Esquelético/fisiología , Miogenina/metabolismo , Animales , Perros
8.
Pflugers Arch ; 433(6): 766-72, 1997 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-9049168

RESUMEN

Using an immunohistochemical double-labeling technique, we observed that different isoforms of sarcoplasmic reticulum Ca-ATPase are co-expressed in single fibers of canine fast-twitch skeletal muscles stimulated chronically at low frequency. By 7 days of neuromuscular stimulation, the population of hybrid fibers expressing both SERCA1 and SERCA2a [fast- and slow-twitch isoforms of sarco(endo)plasmic reticulum Ca(2+)-ATPase] had increased from 1.5% to 9.2% of fibers. By 14 days of stimulation 90% of the pure fast-twitch fibers (expressing only SERCA1) were replaced by hybrid fibers. An additional 28 days of stimulation caused all fast-twitch fibers to express SERCA2a at the same level as found in nonstimulated slow-twitch fibers (expressing only SERCA2a). At this time, one-half of the previously hybrid fibers had become pure-slow-twitch fibers. The remaining one-half of the hybrid fibers expressed SERCA1 at a very low level. Extending stimulation to 70 days did not further change the percentage of fibers that were slow-twitch or hybrid. Immunoblot studies at the whole-muscle level confirmed that changes in SERCA expression at 42 days of neuromuscular stimulation were complete. Immunohistochemical analysis of longitudinal sections of muscle showed that the changes in SERCA protein were uniform along the length of the muscle fiber, indicating that nuclei along its length responded equally to chronic stimulation.


Asunto(s)
ATPasas Transportadoras de Calcio/biosíntesis , Isoenzimas/biosíntesis , Fibras Musculares de Contracción Rápida/enzimología , Fibras Musculares de Contracción Lenta/enzimología , Retículo Sarcoplasmático/enzimología , Animales , Anticuerpos Monoclonales , Membrana Celular/enzimología , Perros , Estimulación Eléctrica , Inmunohistoquímica , Técnicas In Vitro , Fibras Musculares de Contracción Rápida/fisiología , Fibras Musculares de Contracción Lenta/fisiología
9.
J Muscle Res Cell Motil ; 18(1): 81-90, 1997 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9147996

RESUMEN

The canine latissimus dorsi was stimulated at 1 Hz via the thoracodorsal nerve for 70 days. Seven days of muscle stimulation caused muscle mass, fibre cross-sectional areas, and tetanic tensions to decrease. Fourteen days of stimulation produced marked decreases in Ca(2+)-uptake rates in a membrane fraction containing sarcoplasmic reticulum. At this time there was a decline in fusion frequency, but no statistically significant changes in time-to-peak tension, total contraction times, or half-relaxation times. With 42 days of stimulation a switch from the fast-twitch to the slow-twitch phenotype was indicated by elevations in the levels of expression of the slow-twitch isoforms of sarco(endo)plasmic reticulum Ca(2+)-ATPase and myosin heavy chain-I, and increases in half-relaxation times, total contraction times and time-to-peak tensions. Decreases in muscle shortening velocity correlated negatively with increases in myosin heavy chain-I levels. Up-regulation of the slow-twitch isoforms of sarco(endo)plasmic reticulum Ca(2+)-ATPase increases in half-relaxation times. The changes in the slow-twitch isoform of sarco(endo)plasmic reticulum Ca(2+)-ATPase and myosin heavy chain-I levels indicated coordinate expression of these two proteins in chronically stimulated muscles.


Asunto(s)
Músculo Esquelético/fisiología , Unión Neuromuscular/fisiología , Animales , Calcio/metabolismo , ATPasas Transportadoras de Calcio/metabolismo , Perros , Estimulación Eléctrica , Fluoresceína-5-Isotiocianato/metabolismo , Fibras Musculares de Contracción Rápida/metabolismo , Fibras Musculares de Contracción Rápida/fisiología , Fibras Musculares de Contracción Lenta/metabolismo , Fibras Musculares de Contracción Lenta/fisiología , Músculo Esquelético/metabolismo , Cadenas Pesadas de Miosina/metabolismo , Tamaño de los Órganos , Fenotipo
10.
Radiology ; 201(2): 463-6, 1996 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8888241

RESUMEN

PURPOSE: To evaluate the usefulness of computed tomography (CT) in the diagnosis of mediastinitis following median sternotomy. MATERIALS AND METHODS: Fifty patients aged 6 weeks to 80 years (31 male, 19 female) who underwent CT for clinically suspected mediastinitis following median sternotomy were retrospectively identified. CT scans were evaluated for primary findings (localized mediastinal fluid, pneumomediastinum, or both) versus secondary or other findings (mediastinal edema, adenopathy, pleural effusion, or a sternal or lung abnormality). Patients were divided into three groups on the basis of the CT findings and final clinical diagnosis: those with primary CT signs and a final diagnosis of mediastinitis, those with primary CT signs of mediastinitis and a different final diagnosis, and those with neither primary CT findings nor a final diagnosis of mediastinitis. RESULTS: All patients with clinical mediastinitis had primary CT findings. These patients under went CT an average of 24 days after surgery. Patients with primary CT findings and a final clinical diagnosis of something other than mediastinitis underwent CT an average of 9 days following following surgery. Through postoperative day 14, CT had a sensitivity of 100% for clinical mediastinitis but a specificity of 33%; after postoperative day 14, the sensitivity was 100% and the specificity was 100%. CONCLUSION: Primary CT findings are not specific for mediastinitis through postoperative day 14; after day 14, they are highly indicative of mediastinitis.


Asunto(s)
Mediastinitis/diagnóstico por imagen , Complicaciones Posoperatorias , Esternón/cirugía , Tomografía Computarizada por Rayos X , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Diagnóstico Diferencial , Femenino , Humanos , Lactante , Masculino , Mediastinitis/etiología , Persona de Mediana Edad , Sensibilidad y Especificidad , Factores de Tiempo
11.
J Physiol ; 496 ( Pt 1): 211-20, 1996 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-8910209

RESUMEN

1. Salbutamol, a beta 2-agonist, increased the weight of the canine latissimus dorsi muscle. It also increased fusion frequency, and decreased time-to-peak tension, half-relaxation time, and total contraction time. These changes in twitch times and fusion frequency were associated with changes in the levels of proteins expressed in slow- and fast-twitch fibres. Salbutamol decreased the levels of the slow-twitch cardiac isoform of sarco-/endoplasmic reticulum Ca(2+)-ATPase (SERCA2a) and phospholamban proteins, and increased the level of the fast-twitch isoform of sarco-/endoplasmic reticulum Ca(2+)-ATPase (SERCA1a). 2. Changes in the levels of SERCA proteins, particularly SERCA1a, could account for most of the increases in calcium uptake rate observed in homogenates of muscles from the salbutamol-treated animals and could partially account for the changes in half-relaxation rates and other twitch times. 3. Changes in the levels of SERCA1a, SERCA2a and phospholamban protein did not always follow changes in the levels of their corresponding mRNAs. Divergence depended upon the SERCA isoform and muscle. The muscles studied were latissimus dorsi and vastus intermedius. 4. Salbutamol did not change the level of myosin heavy chain (HC)-I isoforms in either muscle, suggesting that it did not increase the proportion of slow-twitch fibres in these muscles. It did increase the level of HC-IIx and decrease the level of HC-IIa isoforms in the latissimus dorsi. Salbutamol did not produce these effects in the vastus intermedius. It is of particular interest that salbutamol changed the relative levels of SERCA proteins in the latissimus dorsi muscle without producing significant change in the level of HC-I isoform.


Asunto(s)
Agonistas Adrenérgicos beta/farmacología , Albuterol/farmacología , Fibras Musculares de Contracción Rápida/fisiología , Músculo Esquelético/fisiología , Agonistas de Receptores Adrenérgicos beta 2 , Animales , Calcio/metabolismo , Proteínas de Unión al Calcio/biosíntesis , ATPasas Transportadoras de Calcio/biosíntesis , Perros , Técnicas In Vitro , Masculino , Contracción Muscular/efectos de los fármacos , Fibras Musculares de Contracción Rápida/efectos de los fármacos , Proteínas Musculares/metabolismo , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/metabolismo , Cadenas Pesadas de Miosina/metabolismo , Fenotipo , ARN Mensajero/biosíntesis , Retículo Sarcoplasmático/efectos de los fármacos , Retículo Sarcoplasmático/enzimología
12.
J Physiol ; 496 ( Pt 1): 221-7, 1996 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-8910210

RESUMEN

1. The effect of simultaneous application of chronic muscle stimulation and salbutamol on the expression of mRNAs and proteins normally expressed by fast- or slow-twitch fibres was followed and the effects of changes in protein expression on mechanical performance were evaluated. Chronic low-frequency stimulation increased the myosin heavy chain (HC)-I level in the canine latissimus dorsi muscle and simultaneous administration of salbutamol partially blocked this change. Associated with the increase in HC-I level was a decrease in the velocity of shortening at zero load, VMAX. The change in VMAX was partially blocked by salbutamol. 2. Chronic low-frequency stimulation increased the levels of slow-twitch cardiac isoform sarco-/endoplasmic reticulum Ca(2+)-ATPase (SERCA2a) and phospholamban mRNA, and SERCA2a and phospholamban protein expression. These changes were associated with an increase in time-to-peak tension and a decrease in fusion frequency. Simultaneous administration of salbutamol blocked these changes in protein expression and muscle mechanics. Chronic stimulation of latissimus dorsi decreased the levels of the fast-twitch isoform of sarco-/endoplasmic reticulum Ca(2+)-ATPase (SERCA1a) and increased SERCA2a protein expression and decreased calcium uptake rate by muscle homogenates. These changes were blocked by salbutamol. 3. The loss of latissimus dorsi muscle weight by chronic stimulation was partially blocked by salbutamol.


Asunto(s)
Agonistas Adrenérgicos beta/farmacología , Albuterol/farmacología , Músculo Esquelético/fisiología , Animales , Calcio/metabolismo , Proteínas de Unión al Calcio/biosíntesis , ATPasas Transportadoras de Calcio/biosíntesis , Perros , Estimulación Eléctrica , Técnicas In Vitro , Masculino , Neuronas Motoras/efectos de los fármacos , Neuronas Motoras/fisiología , Proteínas Musculares/biosíntesis , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/inervación , Cadenas Pesadas de Miosina/biosíntesis , Tamaño de los Órganos/efectos de los fármacos , ARN Mensajero/biosíntesis , Retículo Sarcoplasmático/efectos de los fármacos , Retículo Sarcoplasmático/enzimología
13.
Am J Physiol ; 270(5 Pt 1): C1413-20, 1996 May.
Artículo en Inglés | MEDLINE | ID: mdl-8967442

RESUMEN

To determine whether expression of a nuclear gene encoding a mitochondrial fatty acid oxidation enzyme is regulated in parallel with skeletal muscle fibre-type-specific energy substrate preference, expression of the gene encoding medium-chain acyl-CoA dehydrogenase (MCAD) was delineated in canine latissimus dorsi muscle subjected to chronic motor nerve stimulation. In predominantly fast-twitch canine latissimus dorsi muscle, MCAD mRNA levels were regulated by chronic stimulation in a biphasic pattern. During the 1st wk of stimulation, steady-state MCAD mRNA levels decreased to 50% of unstimulated levels. MCAD mRNA levels began to increase during the 3rd wk of stimulation to reach a level 3.0-fold higher than levels in unstimulated contralateral control muscle by day 70. Immunodetectable MCAD mRNA levels throughout the stimulation period. The temporal pattern and magnitude of MCAD mRNA accumulation in response to muscle stimulation was distinct from that of mRNAs encoding other enzymes known to be regulated by this stimulus, including glyceraldehyde phosphate dehydrogenase, citrate synthase, and sarcoplasmic reticulum Ca-ATPase, but paralleled the protein levels of the peroxisome proliferator-activated receptor (PPAR), an orphan member of the nuclear hormone receptor superfamily known to regulate genes encoding fatty acid oxidation enzymes in liver. The skeletal muscle expression pattern of PPAR was also similar to that of MCAD in unstimulated rat skeletal muscles with distinct fiber-type compositions. These results demonstrate that a nuclear gene encoding a mitochondrial beta-oxidation enzyme is dynamically regulated in a pattern that parallels skeletal muscle fiber-type-specific energy substrate utilization and implicate an orphan nuclear receptor transcription factor as a candidate transducer of this response.


Asunto(s)
Expresión Génica , Músculo Esquelético/fisiología , Acil-CoA Deshidrogenasa , Acil-CoA Deshidrogenasas/genética , Animales , Perros , Estimulación Eléctrica , Homeostasis , Masculino , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Receptores Citoplasmáticos y Nucleares/fisiología , Factores de Tiempo , Factores de Transcripción/fisiología , Transducción Genética
14.
J Surg Oncol ; 61(1): 68-83, 1996 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8544465

RESUMEN

Part I of this study [Spratt JS, Meyer JS, Spratt JA: J Surg Oncol 60:137-146, 1995] reviewed the early reports of investigators, predominantly mathematical biologists and statisticians considering the mathematical laws that would describe the growth of a neoplasm. Included were cytokinetic measurements of the mitotic index, thymidine labeling index, bromodeoxy-uridine labeling index, and the relation of these indices to the potential tumor volume doubling time. The actual doubling time of benign and malignant colonic neoplasms were reported. This second part provides the cumulative observations on the actual doubling times of pulmonary metastases, primary pulmonary cancers, skeletal sarcomas, melanomas, a chemodectoma, tumors of maxillary antrum, testicular cancers, prostate cancer, and the relation between the accumulation of multiple primary cancers and growth rates. The most complete data set is for breast cancer concluding that the cancer growth curve is a decelerating curve with great natural variance. Understanding of the rates of growth of human cancers is essential for understanding the spectrum of cancer behavior observed clinically.


Asunto(s)
Neoplasias Pulmonares/patología , Neoplasias Óseas/patología , Neoplasias de la Mama/patología , División Celular/fisiología , Femenino , Humanos , Modelos Logísticos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/mortalidad , Neoplasias Pulmonares/secundario , Masculino , Melanoma/patología , Neoplasias Primarias Múltiples/patología , Paraganglioma Extraadrenal/patología , Neoplasias de la Próstata/patología , Radiografía Torácica , Análisis de Regresión , Sarcoma/patología , Tasa de Supervivencia , Neoplasias Testiculares/patología
15.
J Surg Oncol ; 60(2): 137-46, 1995 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-7564383

RESUMEN

The purpose of this article is to consolidate data collected from a variety of sources that have permitted calculations of the rates of growth of human neoplasms. These sources include Fischel State Cancer Hospital (Columbia, MO); Mallinckrodt Institute of Radiology, (St. Louis, MO); Roentgen Diagnostic Institute, Allmanna Sjukhuset (Malmo, Sweden); University of Louisville (Louisville, Kentucky); University of Heidelberg (Heidelberg, Germany); and St. Luke's Hospital (St. Louis, MO). Included in the data are laboratory measurements of cell replication rates. All gross measurements were made either on imaging studies or with a centimeter scale for surface or palpable neoplasms. Data have been reported for breast and pulmonary cancers and metastases of many types, melanomas, skeletal sarcomas, benign and malignant colonic neoplasms, and isolated cases of less frequent neoplasms. Related cytokinetic measurements by tritriated thymidine labelling, bromodeoxyuridine labelling, S-phase fraction from DNA flow cytometric analysis, and mitotic indices are discussed. The various mathematical formulae applicable to the analysis of the collected data and the determination of rates and patterns of growth are included. Also considered are the clinical implications of these data and the importance of ever better knowledge on the cytokinetics of human cancer. Prior studies on the evolution of insight into this field are cited and discussed. The authors conclude that a more accurate quantification of the growth rates of human cancer is essential for understanding the biological variance of human cancers seen clinically.


Asunto(s)
Neoplasias/patología , Neoplasias de la Mama/patología , Ciclo Celular , Neoplasias Colorrectales/patología , ADN de Neoplasias/análisis , Citometría de Flujo , Humanos , Pólipos Intestinales/patología , Neoplasias Pulmonares/secundario , Matemática , Índice Mitótico , Estudios Multicéntricos como Asunto
16.
J Surg Res ; 58(6): 665-74, 1995 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-7791345

RESUMEN

Chronic repetitive stimulation of skeletal muscle causes significant changes in contractile mechanics and makes the muscle fatigue resistant. The purpose of this study was to quantify the magnitude and time course of these changes. One latissimus dorsi muscle from each of 28 mongrel dogs was stimulated in situ at 1 Hz for 0, 3, 7, 14, 21, 42, or 70 days. Changes in isometric and isotonic mechanical performance were measured as a function of conditioning time. Isotonic force and velocity data were fitted to the Hill equation to obtain Vmax. The most striking early change was a 30 and 26% decline in muscle mass and cross-sectional area, respectively. Coincident with this was an approximate 40% decline in tetanic and twitch tension. There was a similar decline in the rates of rise and fall of twitch and tetanus tensions (+dT/dt and -dT/dt). The decline in tetanus +dT/dt and -dT/dt followed a similar time course, suggesting that these muscle functions were under similar influences. Calculation of the isometric force data per unit of cross-sectional area minimized the effect of stimulation on isometrically measured muscle function but did not eliminate it. Fusion frequency declined 52% with conditioning. The increases in time-to-peak twitch tension and half-relaxation time were independent of cross-sectional area. Time-to-peak twitch tension and half-relaxation time increased after 7 days of stimulation and became maximal after 42 or 70 days, respectively. Time-to-peak tetanus tension was unchanged by muscle conditioning. Changes in the force-velocity relationship began after 3 days of stimulation, changed very little between 3 and 21 days of stimulation, and showed another change after 42 and 70 days of stimulation. It may be possible to better modify the muscle for dynamic cardiomyoplasty by pharmacological or stimulation regimens once the mechanism of fiber switching is better understood.


Asunto(s)
Cardiomioplastia , Músculo Esquelético/fisiología , Animales , Perros , Estimulación Eléctrica , Contracción Muscular
17.
J Biol Chem ; 270(19): 11619-22, 1995 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-7744801

RESUMEN

Chronic 1 Hz stimulation of the canine latissimus dorsi muscle produced a time-dependent switch from the fast-twitch to the slow-twitch phenotype. This included changes in the proteins of the sarcoplasmic reticulum. After 3 days of muscle stimulation, there was down-regulation of fast-twitch Ca-ATPase (SERCA1a) mRNA and induction of slow-twitch Ca-ATPase (SERCA2a) mRNA; most changes in both mRNAs were nearly complete after 14 days of stimulation. Although the induction of phospholamban mRNA began after 3 days of muscle stimulation, its up-regulation was not completed until the muscle had been stimulated for 42 days. The time course of expression of SERCA2a protein was very different from that of SERCA2a mRNA, suggesting that SERCA2 gene expression is regulated at the translational as well as the transcriptional level. The time course of expression of phospholamban protein closely followed that of phospholamban mRNA, suggesting that this gene is under transcriptional control. Thus coordinated expression of SERCA2a and phospholamban proteins is achieved via translational control of the SERCA2 gene and transcriptional control of the phospholamban gene.


Asunto(s)
Proteínas de Unión al Calcio/biosíntesis , ATPasas Transportadoras de Calcio/biosíntesis , Regulación Enzimológica de la Expresión Génica , Músculo Esquelético/fisiología , Biosíntesis de Proteínas , Retículo Sarcoplasmático/enzimología , Adenosina Trifosfatasas/biosíntesis , Animales , Condicionamiento Psicológico , Perros , Estimulación Eléctrica , Microsomas/enzimología , Fibras Musculares de Contracción Rápida/fisiología , Fibras Musculares de Contracción Lenta/fisiología , Músculo Esquelético/enzimología , Fenotipo , ARN Mensajero/análisis , ARN Mensajero/biosíntesis , Factores de Tiempo , Transcripción Genética
18.
Ann Thorac Surg ; 59(5): 1092-8; discussion 1098-9, 1995 May.
Artículo en Inglés | MEDLINE | ID: mdl-7733703

RESUMEN

A new generation of defibrillators has been introduced that do not require a thoracotomy. The purpose of this report was to examine 100 consecutive nonthoracotomy implantations at our institution and compare them with a series of 102 patients undergoing thoracotomy implantations by the same surgeon over a 4-year period between August 1989 and September 1994. The two groups were comparable for age, sex, comorbidity, cardiac disease status, ejection fraction, and electrophysiologic presentation. Nonthoracotomy systems were implanted successfully in 94% of patients. Patients undergoing a nonthoracotomy implantation had significantly shorter intensive care unit (1.7 +/- 1.7 versus 3.3 +/- 3.9 days; p < 0.005) and postoperative stays (5.0 +/- 2.8 versus 9.5 +/- 5.6 days; p < 0.001) than patients undergoing a thoracotomy approach. This was due to a significant decrease in the incidence of postoperative complications from 29% in the thoracotomy group to 11% in the nonthoracotomy group (p < 0.001). There was no significant difference in overall mortality rates. Nonthoracotomy systems are implantable in the majority of patients and are associated with less morbidity and shorter hospital stays than traditional thoracotomy approaches.


Asunto(s)
Desfibriladores Implantables , Estimulación Cardíaca Artificial , Desfibriladores Implantables/efectos adversos , Electrocardiografía , Femenino , Estudios de Seguimiento , Humanos , Unidades de Cuidados Intensivos , Tiempo de Internación , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias , Tasa de Supervivencia , Taquicardia Ventricular/etiología , Taquicardia Ventricular/fisiopatología , Taquicardia Ventricular/terapia , Toracotomía
19.
Geburtshilfe Frauenheilkd ; 54(5): 286-90, 1994 May.
Artículo en Alemán | MEDLINE | ID: mdl-8050689

RESUMEN

Numerous trials have shown, that breast cancer have highly variable rates of growth. It is assumed, that the rates (relative growth rates) decelerate with increasing tumour size. The Universities of Heidelberg and Louisville carried out a retrospective statistical analysis of the mammographically measured growth rates of 448 screening patients until breast cancer diagnosis. The analysis did not include fast-growing carcinomas appearing between mammograms for which only one mammogram was available or some cancer, where growth was not detectable by mammography. Generalized logistic curves provided the best fit to the data on the increase in tumour size, as observed in mammograms. Large variations in individual tumour doubling times were found, from extremely fast-growing to extremely slow-growing tumours. The results are relevant for patient prognosis, for the evaluation of therapy, and for screening strategies.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , División Celular/fisiología , Mamografía , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias de la Mama/terapia , Femenino , Estudios de Seguimiento , Humanos , Modelos Logísticos , Persona de Mediana Edad , Metástasis de la Neoplasia , Estudios Retrospectivos
20.
Ann Thorac Surg ; 57(4): 1044-50, 1994 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8166512

RESUMEN

Mucormycosis is an opportunistic fungal infection that commonly begins by invading the respiratory tract. The purpose of the present study was to define the clinical presentation of pulmonary mucormycosis and to evaluate current treatment regimens. Thirty patients treated at our institution and 225 cases reported in the literature were reviewed. For the combined groups, the mean age at presentation was 41 +/- 21 years and associated medical conditions included leukemia or lymphoma (37%), diabetes mellitus (32%), chronic renal failure (18%), history of organ transplantation (7.6%), or a known solid tumor (5.6%). The in-hospital mortality was 65% for patients with isolated pulmonary mucormycosis, 96% for those with disseminated disease, and 80% overall. The mortality in patients treated surgically was 11%, significantly lower than the 68% mortality in those treated medically (p = 0.0004). The most common causes of death were fungal sepsis (42%), respiratory insufficiency (27%), and hemoptysis (13%). Pulmonary mucormycosis has a high mortality; however, antifungal agents appear to improve survival. In addition, surgical resection may provide additional benefit to patients with pulmonary mucormycosis confined to one lung.


Asunto(s)
Enfermedades Pulmonares Fúngicas , Mucormicosis , Infecciones Oportunistas , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antifúngicos/uso terapéutico , Causalidad , Causas de Muerte , Niño , Preescolar , Terapia Combinada , Diagnóstico Diferencial , Femenino , Mortalidad Hospitalaria , Humanos , Lactante , Recién Nacido , Enfermedades Pulmonares Fúngicas/diagnóstico , Enfermedades Pulmonares Fúngicas/epidemiología , Enfermedades Pulmonares Fúngicas/etiología , Enfermedades Pulmonares Fúngicas/terapia , Masculino , Persona de Mediana Edad , Mucormicosis/diagnóstico , Mucormicosis/epidemiología , Mucormicosis/etiología , Mucormicosis/terapia , Infecciones Oportunistas/diagnóstico , Infecciones Oportunistas/epidemiología , Infecciones Oportunistas/etiología , Infecciones Oportunistas/terapia , Neumonectomía , Pronóstico , Estudios Retrospectivos , Tasa de Supervivencia , Resultado del Tratamiento
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