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1.
Am J Transplant ; 14(11): 2633-9, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25250717

RESUMEN

We describe two cases of donor-derived methicillin-resistant Staphylococcus aureus (MRSA) bacteremia that developed after transplantation of organs from a common donor who died from acute MRSA endocarditis. Both recipients developed recurrent MRSA infection despite appropriate antibiotic therapy, and required prolonged hospitalization and hospital readmission. Comparison of S. aureus whole genome sequence of DNA extracted from fixed donor tissue and recipients' isolates confirmed donor-derived transmission. Current guidelines emphasize the risk posed by donors with bacteremia from multidrug-resistant organisms. This investigation suggests that, particularly in the setting of donor endocarditis, even a standard course of prophylactic antibiotics may not be sufficient to prevent donor-derived infection.


Asunto(s)
Genoma Bacteriano , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Trasplante de Órganos/efectos adversos , Análisis de Secuencia de ADN , Infecciones Estafilocócicas/transmisión , Donantes de Tejidos , ADN Bacteriano/genética , Humanos , Masculino , Staphylococcus aureus Resistente a Meticilina/genética , Polimorfismo de Nucleótido Simple , Infecciones Estafilocócicas/microbiología
2.
Am J Transplant ; 14(1): 163-71, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24279908

RESUMEN

Primary amebic meningoencephalitis (PAM) caused by the free-living ameba (FLA) Naegleria fowleri is a rare but rapidly fatal disease of the central nervous system (CNS) affecting predominantly young, previously healthy persons. No effective chemotherapeutic prophylaxis or treatment has been identified. Recently, three transplant-associated clusters of encephalitis caused by another FLA, Balamuthia mandrillaris, have occurred, prompting questions regarding the suitability of extra-CNS solid organ transplantation from donors with PAM. During 1995-2012, 21 transplant recipients of solid organs donated by five patients with fatal cases of PAM were reported in the United States. None of the recipients developed PAM, and several recipients tested negative for N. fowleri by serology. However, historical PAM case reports and animal experiments with N. fowleri, combined with new postmortem findings from four patients with PAM, suggest that extra-CNS dissemination of N. fowleri can occur and might pose a risk for disease transmission via transplantation. The risks of transplantation with an organ possibly harboring N. fowleri should be carefully weighed for each individual recipient against the potentially greater risk of delaying transplantation while waiting for another suitable organ. In this article, we present a case series and review existing data to inform such risk assessments.


Asunto(s)
Amebiasis/parasitología , Amebiasis/transmisión , Infecciones Protozoarias del Sistema Nervioso Central/parasitología , Infecciones Protozoarias del Sistema Nervioso Central/transmisión , Naegleria fowleri/patogenicidad , Trasplante de Órganos/efectos adversos , Donantes de Tejidos , Adolescente , Adulto , Amebiasis/mortalidad , Infecciones Protozoarias del Sistema Nervioso Central/mortalidad , Niño , Resultado Fatal , Femenino , Humanos , Masculino
3.
J Med Entomol ; 51(6): 1317-21, 2014 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-26309324

RESUMEN

Amblyomma maculatum Koch, 1844 (also known as the Gulf Coast tick) is found in parts of the Americas, including the central and southern United States. Its primary importance is as the vector of Rickettsia parkeri, a spotted fever group rickettsia that causes an illness similar to, but milder than, Rocky Mountain spotted fever. A second spotted fever group rickettsia, "Candidatus Rickettsia andeanae," was detected in Gulf Coast ticks approximately 10 yr ago. However, the significance of this organism, including pathogenicity, has not yet been well-characterized. Here, we use transmission electron microscopy to describe bacteria within the tissues of A. maculatum ticks that were positive by polymerase chain reaction assay for "Ca. R. andeanae." In ultrathin sections of unfed A. maculatum adult females, we found evidence of bacteria with morphological features consistent with spotted fever group rickettsiae, including small size (≈0.3 by 0.9 µm), a halo zone (electron-lucent layer around the bacterium), and a trilaminar cell wall. In female ticks, bacteria were present in granular salivary glands and ducts, foregut, Malpighian tubules, nerve trunks, and reproductive tissue. These findings demonstrate evidence of "Ca. R. andeanae" in situ and contribute to our understanding of this novel rickettsia in A. maculatum.


Asunto(s)
Ixodidae/microbiología , Rickettsia/ultraestructura , Animales , Femenino , Microscopía Electrónica de Transmisión
4.
Am J Transplant ; 13(12): 3262-8, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24165397

RESUMEN

Since an initial case in 2006, we noted multiple patients undergoing heart transplantation (HTx) for Chagas cardiomyopathy (CC) at our transplant program. The clinical characteristics, laboratory results and outcomes of patients with CC undergoing HTx in the United States have not been reported previously. In 2010, we implemented a systematic screening and management program for patients undergoing HTx for CC. Before HTx, all patients with idiopathic dilated cardiomyopathy who were born in a Chagas disease endemic country were screened for Trypanosoma cruzi (TC) infection with serology. After HTx, monitoring for TC reactivation was performed using clinical visits, echocardiography, endomyocardial biopsy and serial whole blood polymerase chain reaction (PCR) testing. Between June 2006 and January 2012, 11 patients underwent HTx for CC. One patient was empirically treated due to the presence of TC amastigotes in explanted cardiac tissue. Two patients experienced allograft dysfunction due to TC reactivation and three patients experienced subclinical reactivation (positive PCR results), which were treated. Chagas disease is a common cause of dilated cardiomyopathy in patients from endemic countries undergoing HTx at a transplant program in the United States. Reactivation is common after transplantation and can cause adverse outcomes.


Asunto(s)
Cardiomiopatía Chagásica/terapia , Adulto , Anciano , Belice , Biopsia , Cardiomiopatía Chagásica/parasitología , Ecocardiografía , El Salvador , Femenino , Supervivencia de Injerto , Trasplante de Corazón , Humanos , Masculino , México , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Recurrencia , Trypanosoma cruzi/genética , Estados Unidos
5.
J Clin Microbiol ; 50(6): 2173-5, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22495564

RESUMEN

We report a fatal case of Brucella suis endocarditis initially misdiagnosed by automated identification systems as Ochrobactrum anthropi infection in a patient with a history of Marfan syndrome and recreational feral swine hunting. This report emphasizes the need to consider brucellosis as a part of the differential diagnosis of acute febrile illness, particularly in patients with known risk of exposure.


Asunto(s)
Brucella suis/aislamiento & purificación , Brucelosis/diagnóstico , Errores Diagnósticos , Endocarditis Bacteriana/diagnóstico , Síndrome de Marfan/complicaciones , Automatización/métodos , Técnicas Bacteriológicas/métodos , Brucelosis/microbiología , Brucelosis/patología , Endocarditis Bacteriana/microbiología , Endocarditis Bacteriana/patología , Resultado Fatal , Humanos , Masculino , Persona de Mediana Edad , Ochrobactrum anthropi/aislamiento & purificación
6.
Infection ; 39(6): 545-8, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21773760

RESUMEN

BACKGROUND: In a previous controlled study, we investigated the relationship between Bordetella pertussis infections and sudden unexpected deaths among German infants (sudden infant death syndrome, SIDS). In this present study, we investigated further the respiratory pathology in a subset of infants in the original study. METHODS: Originally, there were 234 infants with SIDS and, of these, 12 had either a nasopharyngeal swab (NPS) or a tracheal swab specimen (TS) that was positive for B. pertussis by polymerase chain reaction (PCR). Here, tissue specimens from eight infants who were originally PCR-positive were compared with tissue specimens from seven infants in whom the original PCR studies were negative. RESULTS: The histopathologic diagnoses were as follows: 14 of 15 had pulmonary edema and the remaining case had early diffuse alveolar damage. Although 14 of 15 cases had some histologic or clinical evidence suggesting respiratory tract infection, the features were more consistent with a viral etiology, and in none were the findings typical of respiratory disease attributable to B. pertussis. CONCLUSIONS: The findings in this present investigation do not support a direct role of B. pertussis at the site of infection (ciliated epithelium) in the causation of SIDS. The clinical aspects of this study were carried out in the 1990s when pertussis was widespread in Germany. Therefore, the original finding of some PCR-positive cases is not surprising. The possibility that B. pertussis infection could still be a factor in some SIDS cases, e.g., by a systemic release of toxins, cannot be definitely ruled out.


Asunto(s)
Bordetella pertussis/aislamiento & purificación , Pulmón/patología , Sistema Respiratorio/microbiología , Muerte Súbita del Lactante/etiología , Alemania , Histocitoquímica , Humanos , Lactante , Nasofaringe/microbiología , Reacción en Cadena de la Polimerasa , Tráquea/microbiología , Virosis/patología
7.
Science ; 247(4947): 1219-22, 1990 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-1690453

RESUMEN

An antibody to a platelet integral membrane glycoprotein was found to cross-react with the previously identified CD31 myelomonocytic differentiation antigen and with hec7, an endothelial cell protein that is enriched at intercellular junctions. This antibody identified a complementary DNA clone from an endothelial cell library. The 130-kilodalton translated sequence contained six extracellular immunoglobulin (Ig)-like domains and was most similar to the cell adhesion molecule (CAM) subgroup of the Ig superfamily. This is the only known member of the CAM family on platelets. Its cell surface distribution suggests participation in cellular recognition events.


Asunto(s)
Antígenos de Diferenciación Mielomonocítica/genética , Moléculas de Adhesión Celular/genética , Clonación Molecular , Genes de Inmunoglobulinas , Secuencia de Aminoácidos , Anticuerpos Monoclonales , ADN/análisis , Endotelio Vascular/análisis , Endotelio Vascular/inmunología , Epítopos/inmunología , Humanos , Immunoblotting , Inmunoglobulinas , Técnicas de Inmunoadsorción , Datos de Secuencia Molecular , Molécula-1 de Adhesión Celular Endotelial de Plaqueta , Glicoproteínas de Membrana Plaquetaria/inmunología , Conformación Proteica , Secuencias Repetitivas de Ácidos Nucleicos , Homología de Secuencia de Ácido Nucleico , Transducción de Señal
8.
Curr Top Microbiol Immunol ; 315: 289-324, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17848069

RESUMEN

Two infectious diseases, and one presumably infectious disease, each vectored by or associated with the bite of the lone star tick (Amblyomma americanum), were identified and characterized by clinicians and scientists in the United States during the 1980s and 1990s. These three conditions-human monocytic (or monocytotropic) ehrlichiosis (HME), Ehrlichia ewingii ehrlichiosis, and southern tick-associated rash illness (STARI)-undoubtedly existed in the United States prior to this time. However, the near-simultaneous recognition of these diseases is remarkable and suggests the involvement of a unifying process that thrust multiple pathogens into the sphere of human recognition. Previous works by other investigators have emphasized the pivotal role of white-tailed deer (Odocoileus virginianus) in the emergence of Lyme disease, human babesiosis, and human granulocytic anaplasmosis. Because whitetails serve as a keystone host for all stages of lone star ticks, and an important reservoir host for Ehrlichia chaffeensis, E. ewingii, and Borrelia lonestari, the near-exponential growth of white-tailed deer populations that occurred in the eastern United States during the twentieth century is likely to have dramatically affected the frequency and distribution of A. americanum-associated zoonoses. This chapter describes the natural histories of the pathogens definitively or putatively associated with HME, E. ewingii ehrlichiosis, and STARI; the role of white-tailed deer as hosts to lone star ticks and the agents of these diseases; and the cascade of ecologic disturbances to the landscape of the United States that have occurred during the last 200 years that provided critical leverage in the proliferation of white-tailed deer, and ultimately resulted in the emergence of these diseases in human populations.


Asunto(s)
Vectores Arácnidos/microbiología , Infecciones por Borrelia/transmisión , Ciervos , Ehrlichiosis/transmisión , Garrapatas/microbiología , Zoonosis , Animales , Infecciones por Borrelia/epidemiología , Infecciones por Borrelia/veterinaria , Ciervos/microbiología , Ciervos/parasitología , Reservorios de Enfermedades/veterinaria , Ehrlichiosis/epidemiología , Ehrlichiosis/veterinaria , Humanos , Estados Unidos/epidemiología
9.
J Clin Invest ; 95(4): 1553-60, 1995 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-7706461

RESUMEN

To gain insight into region of the platelet GPIIb-IIIa complex involved in receptor biogenesis and function, we examined the biochemical properties of a defective GPIIb-IIIa complex from patient suffering from type II Glanzmann thrombasthenia. Flow cytometric as well as immunoblot analysis of patient platelets showed significantly reduced levels of GPIIb and GPIIIa compared with a normal control. Patient platelets, however, retained the ability to retract a fibrin clot. Sequence analysis of PCR-amplified platelet GPIIb mRNA revealed an Arg327-->His amino acid substitution between the second and third calcium-binding domains of the GPIIb heavy chain, a residue that is highly conserved among integrin alpha-subunits. The recombinant His327 form of GPIIb was found to be fully capable of associating with GPIIIa, therefore the role of the calcium-binding domains in intersubunit association was further examined by constructing amino-terminal segments of GPIIb that ended before the first, second, and third calcium-binding domains. All three fragments were found to associate with GPIIIa, demonstrating that the calcium-binding domains of GPIIb are not necessary for initial complex formation. Regions amino-terminal to the calcium-binding domains of GPIIb may play a heretofore unappreciated role in integrin subunit association.


Asunto(s)
Calcio/metabolismo , Fibrinógeno/metabolismo , Mutación , Glicoproteínas de Membrana Plaquetaria/genética , Trombastenia/genética , Adolescente , Secuencia de Aminoácidos , Secuencia de Bases , Plaquetas/fisiología , Femenino , Citometría de Flujo , Humanos , Integrinas/metabolismo , Datos de Secuencia Molecular , Procesamiento Proteico-Postraduccional , Relación Estructura-Actividad
10.
Ann N Y Acad Sci ; 1078: 342-3, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17114736

RESUMEN

This study describes preliminary results of an investigation of RMSF in Arizona associated with the brown dog tick, Rhipicephalus sanguineus. High numbers of dogs and heavy infestations of ticks created a situation leading to human disease.


Asunto(s)
Rhipicephalus sanguineus/microbiología , Fiebre Maculosa de las Montañas Rocosas/epidemiología , Animales , Arizona/epidemiología , Dermacentor/microbiología , Humanos , Incidencia
11.
J Bone Miner Res ; 10(2): 211-21, 1995 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-7754801

RESUMEN

To investigate the dose-dependent effects of risedronate on cancellous bone remodeling, adult female beagle dogs were treated with either placebo, 0.1, 0.5, or 2.5 mg/kg/day of risedronate orally in an intermittent cyclic regimen (7 days on 21 days off), repeated three times. Iliac cancellous bone samples were subjected to histomorphometric analysis and three-dimensional (3-D) kinetic reconstruction of the remodeling site was performed. In the 0.1 mg/kg dose group, resorption and activation indices were no different from the placebo group. However, wall thickness was increased resulting in a positive bone balance at the level of the remodeling unit. In the 0.5 and 2.5 mg/kg dose groups, a dose-dependent reduction in activation frequency and tissue level bone formation was observed. Resorption rates were also significantly decreased, 60% and 80% for the 0.5- and 2.5-mg/kg groups, respectively. An approximate 25% reduction in final erosion depth was noted in both these groups. Analyses of the growth curves of the bone packet confirmed that the kinetics of the growth of a completed packet were different in the 0.5- and 2.5-mg/kg dose groups compared with placebo. These changes were associated with a significant increase in the final wall thickness in both groups indicating no net impairment of osteoblast function. These increases in wall thickness in combination with the reductions in final erosion depth in the 0.5 and 2.5 mg/kg groups resulted in a significant dose-dependent positive bone balance. This pharmacological profile suggests that risedronate may be of therapeutic utility in the treatment of metabolic bone diseases where reductions in activation frequency and resorptive cell activity at the level of the remodeling unit are a therapeutic goal.


Asunto(s)
Remodelación Ósea/efectos de los fármacos , Bloqueadores de los Canales de Calcio/farmacología , Ácido Etidrónico/análogos & derivados , Ilion/efectos de los fármacos , Osteoblastos/efectos de los fármacos , Administración Oral , Animales , Densidad Ósea/efectos de los fármacos , Desarrollo Óseo/efectos de los fármacos , Enfermedades Óseas Metabólicas/tratamiento farmacológico , Resorción Ósea/tratamiento farmacológico , Bloqueadores de los Canales de Calcio/administración & dosificación , Bloqueadores de los Canales de Calcio/uso terapéutico , Pared Celular/efectos de los fármacos , Perros , Relación Dosis-Respuesta a Droga , Ácido Etidrónico/administración & dosificación , Ácido Etidrónico/farmacología , Ácido Etidrónico/uso terapéutico , Femenino , Humanos , Cinética , Modelos Biológicos , Modelos Teóricos , Osteoblastos/citología , Osteoporosis Posmenopáusica/tratamiento farmacológico , Ácido Risedrónico
12.
J Bone Miner Res ; 11(5): 600-13, 1996 May.
Artículo en Inglés | MEDLINE | ID: mdl-9157775

RESUMEN

Therapies utilizing intermittent human parathyroid hormone(1-34) (hPTH[1-34]) in combination with other agents have recently been proposed as possible anabolic regimens for the treatment of osteoporosis. We conducted a 24 week study in aged beagle dogs to determine the effects of intermittent hPTH(1-34) administered alone or in combination with 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) on the endosteal remodeling in cancellous and cortical bone. Additionally, we tested the interaction between hPTH(1-34) and a new potent bisphosphonate, risedronate. The three treatment groups were compared with a vehicle control group. Kinetic reconstruction of the remodeling unit revealed substantial differences between the groups in resorption and formation at the basic multicellular unit level. Although the estimates of final erosion depth were unaffected by treatment, tunneling resorption was noted in six of the eight dogs administered hPTH(1-34) alone. These qualitative morphological changes in the resorption lacunae were attenuated or absent in dogs administered hPTH(1-34) in combination with either 1,25(OH)(2)D(3) or risedronate. Functional periods for resorption were significantly increased, and the resorption rates were significantly decreased in the hPTH(1-34) + risedronate group. Analyses of the formative site demonstrated that the wall thickness was significantly increased and the bone balance significantly more positive in all three hPTH(1-34) treatment groups. The most positive bone balance was achieved in the combined hPTH(1-34) + risedronate group (+ 15.6 + or - 14.2 mm, p <0.05). Increases in the mineral apposition rate in the early phases of the formative period suggest that an increase in osteoblastic activity (number or function) may contribute to the increase in wall thickness. Treatment with hPTH(1-34) alone or in combination with 1,25(OH)(2)D(3) caused an approximately 2-fold increase in the activation frequency in cancellous bone, which was essentially normalized to control values by the coadministration of risedronate. The impact of these changes on the cancellous bone microstructure was significant only in the combined hPTH(1-34) + risedronate group where normalized bone turnover in the face of a positive bone balance effected a significant increase in the trabecular thickness. Analyses of sequential fluorochrome labels, administered to reconstruct the temporal changes in intracortical activation, demonstrated the presence of an apparent cyclic pattern of activation in the cortex of placebo-treated dogs. Generally, activation was increased throughout the study in dogs administered hPTH(1-34) alone or in combination. However, in the hPTH(1-34) + risedronate group, activation was significantly blunted toward the end of the study, and the cyclic pattern of activation was modulated. These data suggest that intermittent hPTH(1-34) in combination with risedronate may be superior to hPTH(1-34) in combination with 1,25(OH)(2)D(3) as a therapeutic regimen for osteoporosis due to the protective effect of this bisphosphonate on the cortical and endocortical envelope.


Asunto(s)
Remodelación Ósea/efectos de los fármacos , Huesos/patología , Calcitriol/administración & dosificación , Bloqueadores de los Canales de Calcio/administración & dosificación , Calcio/metabolismo , Ácido Etidrónico/análogos & derivados , Teriparatido/administración & dosificación , Animales , Huesos/efectos de los fármacos , Huesos/metabolismo , Perros , Quimioterapia Combinada , Ácido Etidrónico/administración & dosificación , Humanos , Ácido Risedrónico
13.
J Bone Miner Res ; 7(4): 425-32, 1992 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1609630

RESUMEN

Agents that exert anabolic effects on bone have generally been tested in young or estrogen-replete animals. It is unclear whether these agents exert similar effects in older ovariectomized (Ovx) animals. In this single study we examined the effects of intermittent (daily) human PTH-(1-34) and continuous infusion of human recombinant IGF-I alone and in combination on bone resorption and formation over a 14 day period in an aged Ovx rat model of postmenopausal osteoporosis (2-year-old rats, Ovx at 1 year). Compared to Ovx controls, PTH treatment increased bone mineral content (BMC) and bone volume and stimulated bone formation but had no effect on bone resorption. In contrast, IGF-I treatment reduced BMC and stimulated resorptive activity as assessed by increases in marrow volume, cortical porosity, osteoclast-positive eroded surfaces, and urinary hydroxyproline excretion. IGF-I had no effect on bone formation, but when combined with PTH, IGF-I blunted the response to PTH on the periosteal and endocortical surfaces. In summary, PTH stimulated bone formation in a manner similar to that observed in younger animals and IGF-I stimulated bone resorption rather than formation and blunted the bone-forming response to PTH. The effects of IGF-I in older Ovx rats may differ from those observed in younger estrogen-replete animals.


Asunto(s)
Envejecimiento/efectos de los fármacos , Factor I del Crecimiento Similar a la Insulina/farmacología , Osteoporosis Posmenopáusica/tratamiento farmacológico , Ovario/fisiología , Hormona Paratiroidea/farmacología , Envejecimiento/fisiología , Animales , Densidad Ósea/efectos de los fármacos , Modelos Animales de Enfermedad , Femenino , Fémur/efectos de los fármacos , Fémur/patología , Humanos , Bombas de Infusión Implantables , Inyecciones Subcutáneas , Osteoporosis Posmenopáusica/fisiopatología , Ovariectomía , Ratas , Ratas Endogámicas , Columna Vertebral/efectos de los fármacos , Columna Vertebral/patología
14.
Clin Infect Dis ; 39(3): e21-4, 2004 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-15307019

RESUMEN

A 65-year-old man developed massive hemoperitoneum secondary to spontaneous splenic rupture. Histopathological analysis of the spleen demonstrated necrotizing granulomas. Results of serological tests indicated infection with a species of Bartonella, and immunohistochemical staining established Bartonella henselae as the cause of splenitis. To our knowledge, this represents the first reported case of spontaneous splenic rupture caused by infection with a species of Bartonella.


Asunto(s)
Infecciones por Bartonella/complicaciones , Bartonella henselae , Rotura del Bazo/microbiología , Anciano , Angiomatosis Bacilar , Anticuerpos Antibacterianos/sangre , Infecciones por Bartonella/diagnóstico , Bartonella henselae/inmunología , Bartonella henselae/aislamiento & purificación , Técnica del Anticuerpo Fluorescente Indirecta , Granuloma/microbiología , Hemoperitoneo/microbiología , Humanos , Inmunohistoquímica , Ganglios Linfáticos/microbiología , Masculino , Rotura Espontánea/microbiología , Rotura Espontánea/patología , Bazo/microbiología , Rotura del Bazo/patología
15.
Microbes Infect ; 2(10): 1193-205, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11008109

RESUMEN

Bartonella species were virtually unrecognized as modern pathogens of humans until the last decade. However, identification of Bartonella species as the agents of cat-scratch disease, bacillary angiomatosis, urban trench fever, and possible novel presentations of Carrion's disease has left little doubt of the emerging medical importance of this genus of organisms. The three primary human pathogenic bartonellae, Bartonella bacilliformis (Carrion's disease), B. henselae (cat-scratch disease), and B. quintana (trench fever), present noteworthy comparisons in the epidemiology, natural history, pathology, and host-microbe interaction that this review will briefly explore.


Asunto(s)
Infecciones por Bartonella , Bartonella/patogenicidad , Zoonosis , Animales , Infecciones por Bartonella/historia , Infecciones por Bartonella/microbiología , Infecciones por Bartonella/transmisión , Bartonella henselae/patogenicidad , Bartonella quintana/patogenicidad , Reservorios de Enfermedades , Historia del Siglo XIX , Historia del Siglo XX , Humanos , Zoonosis/historia , Zoonosis/microbiología , Zoonosis/transmisión
16.
Bone ; 16(3): 381-3, 1995 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7786642

RESUMEN

Numerous methods are currently being employed to estimate completed wall thickness and final erosion depth. Conflicting estimates of calculated bone balance have been obtained from the estimates of wall thickness and erosion depth using these various methods. To assess the utility of two specific methods to estimate wall thickness (polarized microscopy) and erosion depth (lamellar counts), we conducted a study in normal young adult beagle dogs, a model where bone balance should approximate 0. Dogs were administered multiple fluorochrome labels in vivo to label activity forming bone pockets. These labels were used to confirm the position of the cement line of the bone structural unit (BSU) in fluorescent light. Parallel measurements of wall thickness were then collected in polarized light. These estimates were compared to estimates of erosion depth obtained by lamellar counting and bone balance was calculated. Estimates of wall thickness correlated well with estimates of erosion depth with bone balance not differing significantly from 0. These data suggest that the combination of these two methods is a reasonable approach to obtaining estimates of bone balance at the level of the remodeling unit.


Asunto(s)
Remodelación Ósea/fisiología , Huesos/patología , Colorantes Fluorescentes/química , Osteoblastos/citología , Animales , Perros , Masculino , Microscopía de Polarización , Osteoblastos/patología , Distribución Aleatoria
17.
Bone ; 16(2): 209-13, 1995 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-7756049

RESUMEN

Newly developed unbiased stereological methods were employed to investigate the effects of estrogen deficiency on the three-dimensional connectivity of vertebral cancellous bone from ovariectomized (OVX) rats. The effects of two classes of antiresorptive agents, estrogen and bisphosphonates, on changes in connectivity in this animal model were also evaluated. Female rats were either sham-operated (sham-op) or surgically OVX at 90 days of age. OVX rats were administered either vehicle, estrogen (10 micrograms/kg 17-beta estradiol, 5 days/week subcutaneously [SC], etidronate disodium (5 mg/kg SC) or risedronate (5 micrograms/kg SC). The bisphosphonates were administered daily for 1 week followed by 3 weeks with no treatment. Treatment duration was 360 days. Systematic random sections, 30-microns thick, were prepared from methylmethacrylate-embedded decalcified second lumbar vertebrae. Total trabecular number and connectivity density were estimated using the ConnEulor principle. Vertebral cancellous bone volume was estimated on undecalcified sections from the first lumbar vertebrae. Connectivity density and cancellous bone volume were significantly reduced (approximately 25% and 40%, respectively) in the OVX group compared with the sham-op group. Estrogen treatment essentially maintained connectivity and cancellous bone volume at the level of the sham-op rats. Connectivity density and total trabecular number were significantly increased in the etidronate- and risedronate-treated rats compared with both the sham-op and OVX rats. These data demonstrate that reduction in the three-dimensional connectivity of vertebral cancellous bone is a long-term consequence of ovariectomy in the rat. This reduction in connectivity can be effectively prevented by the administration of antiresorptive agents such as estrogen, etidronate and risedronate.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Bloqueadores de los Canales de Calcio/uso terapéutico , Estradiol/uso terapéutico , Ácido Etidrónico/análogos & derivados , Ácido Etidrónico/uso terapéutico , Osteoporosis Posmenopáusica/tratamiento farmacológico , Animales , Resorción Ósea/tratamiento farmacológico , Bloqueadores de los Canales de Calcio/administración & dosificación , Bloqueadores de los Canales de Calcio/farmacología , Modelos Animales de Enfermedad , Estradiol/administración & dosificación , Estradiol/farmacología , Ácido Etidrónico/administración & dosificación , Ácido Etidrónico/farmacología , Femenino , Humanos , Vértebras Lumbares/efectos de los fármacos , Vértebras Lumbares/patología , Vértebras Lumbares/ultraestructura , Ovariectomía , Ratas , Ratas Sprague-Dawley , Ácido Risedrónico
18.
Bone ; 16(6): 637-42, 1995 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-7669440

RESUMEN

The topological changes in vertebral cancellous bone were estimated in vertebrae from calcium-restricted ovariectomized Sinclair S-1 minipigs, a recently described animal model of cancellous osteopenia. Connectivity was estimated using unbiased stereological principles in disector pairs of sections from the first lumbar vertebrae. Connectivity density was increased approximately twofold when compared with sham-operated minipigs fed a standard diet. These alterations in topology occurred coincident with a 25% increase in final resorption depth and a 150% increase in vertebral marrow star volume. Taken together, these changes suggest that in calcium-restricted ovariectomized minipigs, trabecular plates are transformed into rods by perforation. These changes in topology appear to be due, at least in part, to excessive resorptive cell function at the level of the bone remodeling unit. Conventional two-dimensional estimators of structural parameters of cancellous bone were not only less sensitive to these changes in topology but, in some cases, the estimates were directionally reversed.


Asunto(s)
Densidad Ósea/fisiología , Calcio/deficiencia , Vértebras Lumbares/fisiología , Osteoporosis Posmenopáusica/fisiopatología , Animales , Fenómenos Biomecánicos , Enfermedades Óseas Metabólicas/metabolismo , Enfermedades Óseas Metabólicas/fisiopatología , Resorción Ósea/fisiopatología , Modelos Animales de Enfermedad , Femenino , Humanos , Osteoporosis Posmenopáusica/metabolismo , Ovariectomía/efectos adversos , Porcinos , Porcinos Enanos
19.
Ann N Y Acad Sci ; 990: 295-301, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12860642

RESUMEN

Rocky Mountain spotted fever (RMSF), a tick-borne illness that has its highest incidence in the south central and southeastern United States, is often a diagnostic challenge, as patients frequently present with nonspecific symptoms during the early stages of illness. RMSF has a high case fatality rate among untreated individuals, and the median time from onset of symptoms to death is only eight days, making early recognition and treatment of RMSF crucial. In two Mississippi public health districts, 148 primary care physicians were randomly selected and mailed surveys regarding RMSF diagnosis, treatment, and prevention. Eighty-four of the 148 (57%) physicians responded. Responses from different specialties and different health districts were compared using chi square statistics. Almost all (99%) physicians correctly identified doxycycline as the antibiotic agent of choice for treating adults and adolescents. However, only 21% of family practice physicians, and 25% of emergency medicine physicians correctly identified the antibiotic of choice for treating children with RMSF. Twenty-three percent of physicians responded that waiting for the development of a rash before prescribing antibiotics is an appropriate treatment strategy. The current standard of care-doxycycline as the agent of choice among children 8 years of age or younger with suspected RMSF-has not been effectively communicated to all physicians caring for children. Also, many physicians are not familiar with the rationale underlying initiation of antibiotic therapy prior to the development of rash in patients with suspected RMSF. Continuing education efforts should focus on antibiotic selection in pediatric patients and initiation of therapy prior to the onset of rash in appropriate patients.


Asunto(s)
Antibacterianos/uso terapéutico , Medicina , Fiebre Maculosa de las Montañas Rocosas/diagnóstico , Fiebre Maculosa de las Montañas Rocosas/tratamiento farmacológico , Especialización , Animales , Conocimientos, Actitudes y Práctica en Salud , Humanos , Mississippi , Rickettsia rickettsii , Garrapatas/microbiología , Resultado del Tratamiento
20.
Am J Trop Med Hyg ; 65(5): 603-9, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11716122

RESUMEN

In the United States, human ehrlichiosis is a complex of emerging tick-borne diseases caused by 3 distinct Ehrlichia species: Ehrlichia chaffeensis, Ehrlichia ewingii, and the human granulocytotropic ehrlichiosis agent. Ehrlichioses are characterized by a mild to severe illness, and approximately 4% of cases are fatal. Because these obligate intracellular bacteria are difficult to resolve with routine histologic techniques, their distribution in tissues has not been well described. To facilitate the visualization and detection of ehrlichiae, immunohistochemistry (IHC), in situ hybridization (ISH), and polymerase chain reaction (PCR) assays were developed by use of tissues from 4 fatal cases of E. chaffeensis infection. Evidence of E. chaffeensis via IHC, ISH, and PCR was documented in all 4 cases. Abundant immunostaining and in situ nucleic acid hybridization were observed in spleen and lymph node from all 4 patients. Significantly, in 2 of these patients, serologic evidence of infection was absent. Use of IHC, ISH, and PCR to visualize and detect Ehrlichia in tissues can facilitate diagnosis of ehrlichial infections.


Asunto(s)
Ehrlichia chaffeensis , Ehrlichiosis/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Inmunohistoquímica , Hibridación in Situ , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa
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