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Biomedical subjects

C Hartley

Publications and source records attributed to C Hartley.

At least 19 recordsLinked to original sources

The absence of desmin leads to cardiomyocyte hypertrophy and cardiac dilation with compromised systolic function.

Desmin is the muscle-specific member of the intermediate filament family of cytoskeletal proteins, expressed both in striated and smooth muscle tissues. In mature striated muscle fibers, the desmin filament lattice surrounds the Z-discs, interconnects them to each other and links the entire contractile apparatus to the sarcolemmal cytoskeleton, cytoplasmic organelles and the nucleus. There have been increasing reports of human cardiomyopathies associated with abnormal accumulation and aggregation of desmin filaments. Recently identified desmin mutations in humans suffering from skeletal muscle myopathy and cardiomyopathy suggest that these diseases might arise as a consequence of impaired function of desmin filaments. Previous generation of desmin null mice in our laboratory demonstrated that the absence of desmin results in myocyte ultrastructural defects and myocyte cell death leading to fibrosis and calcification of the myocardium. However, the effects that these defects have on cardiac function were not addressed. To further our understanding of desmin function in vivo, and in order to address the direct involvement of desmin in cardiomyopathy, we investigated the effect of the absence of desmin on myocardial mass, myocyte size and shape, changes in gene expression and cardiac systolic and diastolic function in mice. Morphometric characterization of isolated cardiomyocytes demonstrated a 24% increase in cell volume in the desmin null mice, solely due to an increase in transverse section area, suggesting for the first time that mice lacking the intermediate filament protein desmin develop concentric cardiomyocyte hypertrophy. This type of hypertrophy was accompanied by induction of embryonic gene expression and later by ventricular dilatation, and compromised systolic function. These results demonstrate that desmin is essential for normal cardiac function, and they suggest that the absence of an intact desmin filament system, rather than accumulation of the protein, may be responsible for the pathology seen in some of the desmin associated cardiomyopathies.

Animals↗

A new form of Filgrastim with sustained duration in vivo and enhanced ability to mobilize PBPC in both mice and humans.

Granulocyte colony-stimulating factor (G-CSF) has proven effective in the prophylaxis of chemotherapy-induced neutropenia and as a mobilizer of peripheral blood progenitor cells. The longevity of G-CSF action is limited by its removal from the body by two mechanisms. The first is thought to be mediated via receptors (receptor mediated clearance [RMC]) predominantly on neutrophils, the second process is likely the result of renal clearance. With the intention of developing a novel form of Filgrastim (r-met HuG-CSF) with a sustained duration of action in vivo, a new derivative named SD/01 has been made by association of Filgrastim with poly(ethylene glycol). The desired properties of this new agent would include a prolonged duration of action sufficient to cover a complete single course of chemotherapy. SD/01 is shown here to sustain significantly elevated neutrophil counts in hematopoietically normal mice for 5 days. In neutropenic mice effects were noted for at least 9 days, accompanying a significant reduction in the duration of chemotherapy induced neutropenia. Normal human volunteers showed higher than baseline ANC for around 9 to 10 days after a single injection of SD/01. Data from these normal volunteers also indicate that mobilization of CD34+ cells and progenitors may occur in a more timely manner and to around the same absolute numbers as with repeated daily injections of unmodified Filgrastim. These data indicate that SD/01 represents an efficacious novel form of Filgrastim with actions sustained for between one and two weeks from a single injection.

Animals↗

PEG-rHuMGDF promotes multilineage hematopoietic recovery in myelosuppressed mice.

PEG-rHuMGDF administered to normal mice is a lineage-specific growth factor for megakaryocytes and platelets as judged by morphologic examination of hematologic cells in marrow and peripheral blood smears. The purpose of this study was to document that PEG-rHuMGDF in myelosuppressed mice promotes multilineage hematopoietic recovery. High-dose 5-fluorouracil (5-FU) in mice results in profound myelosuppression and 0-30% survival. Mice receiving a single dose of PEG-rHuMGDF (1000 microg/kg) 1 day after 5-FU (225 mg/kg) demonstrate an increased survival (76% vs 27% in control mice at 14 days). Compared to surviving controls, PEG-rHuMGDF-treated mice not only show the expected higher platelet counts, but also increased marrow colony-forming unit granulocyte-macrophage, increased multilineage marrow cellularity, and increased neutrophil, monocyte, and lymphocyte counts in peripheral blood. PEG-rHuMGDF- and vehicle-treated mice both develop hepatic abscesses after 5-FU treatment, but the abscesses in the PEG-rHuMGDF-treated mice contain more neutrophils, suggesting that myeloid reconstitution contributes to their survival. Furthermore, survival in 5-FU-treated mice is significantly improved by granulocyte colony-stimulating factor and antibiotics, suggesting that infection rather than thrombocytopenia is the predominant cause of death. PEG-rHuMGDF after 5-FU promotes survival accompanied by accelerated lymphohematopoietic repopulation, suggesting that PEG-rHuMGDF, a lineage-specific thrombopoietic factor in normal mice, promotes multilineage hematopoietic recovery in myelosuppressed mice.

Animals↗

Surfactant protein A binds to the fusion glycoprotein of respiratory syncytial virus and neutralizes virion infectivity.

Collectins are a family of calcium-dependent collagenous lectins that appear to be important in innate host defense. We investigated the ability of three human collectins, namely, lung surfactant proteins A (SP-A) and D (SP-D) and the serum mannose-binding protein (MBP), to bind to the surface glycoproteins of respiratory syncytial virus (RSV). SP-A was shown to bind to the F (fusion) glycoprotein but not to the viral G (attachment) glycoprotein, and binding was completely abrogated in the presence of EDTA. Neither SP-D nor MBP bound to either glycoprotein. SP-A also neutralized RSV in a calcium dependent fashion. These results support a role for SP-A in the defense of infants against infection with RSV and indicate a possible mechanism for its protective activity.

Animals↗

Vestibular closure with a silastic obturator--an alternative to Young's procedure in bleeding diathesis.

Epistaxis is a common and difficult problem to manage in patients with bleeding disorders. We present a case of recurrent epistaxis in a patient with Bernard-Soulier syndrome (a platelet disorder) and describe a non-invasive but effective method of closing the nasal vestibule using a silastic obturator thus preventing the drying effects of airflow on the nasal mucosa which may precipitate epistaxis in patients with a bleeding diathesis.

Adult↗

Primary non-Hodgkin's lymphoma of the larynx in an AIDS patient.

A case of primary non-Hodgkin's lymphoma of the larynx in an AIDS patient is presented with a review of the literature. Non-Hodgkin's lymphomas in AIDS patients are common but the primary laryngeal presentation is very rare. The symptoms usually include dysphonia and progressive airway obstruction requiring tracheostomy. As with laryngeal non-Hodgkin's laryngeal lymphomas in non-HIV positive patients the majority are of B cell lineage and respond well to radiotherapy. Our patient had a high grade lymphoma of B cell lineage which showed a good response to radiotherapy. The role of chemotherapy and surgery is not yet established. We suggest that the diagnosis of AIDS should not influence the management of these patients unless the individual is in the terminal disease stage.

Adult↗

Closure of the nasal vestibule in atrophic rhinitis--a new non-surgical technique.

A new technique is described for closing the nasal vestibule in cases of secondarily-acquired atrophic rhinitis. This involves occlusion of the nasal vestibule with an obturator made from dimethylpolysiloxane. Being a non-invasive method it is specifically indicated in the management of cases of secondarily-acquired atrophic rhinitis where any surgical treatment is contra-indicated. We describe its use in a case each of unilateral and bilateral secondary atrophic rhinitis.

Adult↗

Marrow repopulating cells in mobilized PBPC can be serially transplanted for up to five generations or be remobilized in PBPC reconstituted mice.

We have evaluated the durability of engraftment and the potential of remobilization in mice reconstituted with mobilized peripheral blood progenitor cells (PBPC). Female mice which had been reconstituted with cytokine-mobilized PBPC from male donors were serially transplanted into second, third, fourth and fifth lethally irradiated female recipients at intervals of 6-10 months. Male-derived hematopoiesis was determined in recipient mice at each serial transplantation. Male-positive CFCs were detected after 5 passages for 45 months, but declined from >95% at passage 1 to 74% at passage 2, 33% at passage 4, and 28% at passage 5. Long-term survival also declined from 97% at passage 2 to 53% at passage 4, and 27% at passage 5. The results demonstrated that mobilized PBPC were able to provide engraftment for more than 45 months, but the engraftment provided by mobilized PBPC decreased at each serial passage. In addition, mice reconstituted with mobilized PBPC (at 1 year post transplantation) were treated with the same cytokines as in the primary mobilization (remobilization). The remobilized PBPC were harvested and transplanted into lethally irradiated secondary recipients. Male-derived CFCs were evaluated at 20 months post transplantation. Mice transplanted with PBPC remobilized with rhG-CSF or rhG-CSF plus rrSCF-PEG showed 70% and 89% male-positive CFCs respectively, demonstrating that mice reconstituted with mobilized PBPC could be remobilized and that the remobilized PBPC were also capable of providing long-term hematopoietic reconstitution. Our studies demonstrated that mobilized PBPC have extensive proliferative or self-renewal capacity to provide durable engraftment and that marrow repopulating cells in PBPC reconstituted mice can be remobilized, suggesting that patients who relapse after PBPC transplantation may be remobilized for a second transplantation to support additional chemotherapy.

Animals↗

Microbiology and antibiotic treatment of head and neck abscesses in children.

The clinical data, microbiological results and antibiotic treatment of 65 children who have required incision and drainage of suppurative head and neck abscesses was retrospectively investigated with the aim of developing a more effective clinical protocol of treatment, improving speed of resolution and rationalizing the need for surgical intervention. A positive culture grew in 78% of children and of these 45% were Staphylococcus aureus, 9% Streptococcus pyogenes, and 8% atypical mycobacteria. Only 3% of the samples grew anaerobes. All isolates of S. aureus were sensitive to Flucloxacillin and all isolates of S. pyogenes were sensitive to penicillin. All anaerobes were Metronidazole sensitive. In 40% of the children there were no localizing symptoms which could guide the treatment, therefore we recommend Flucloxacillin and Metronidazole as the antibiotic regimen of choice in acute suppurative lymphadenitis. The increasing incidence of atypical mycobacterial lymphadenitis is noteworthy.

Abscess↗

Chronic expression of murine flt3 ligand in mice results in increased circulating white blood cell levels and abnormal cellular infiltrates associated with splenic fibrosis.

The effect of chronic expression of flt3 ligand (FL) on in vivo hematopoiesis was studied. Retroviral vector-mediated gene transfer was used in a mouse model of bone marrow transplantation to enforce expression of mouse FL cDNA in hematopoietic tissues. As early as 2 weeks posttransplantation, peripheral blood white blood cell counts in FL-overexpressing recipients were significantly elevated compared with controls. With the exception of eosinophils, all nucleated cell lineages studied were similarly affected in these animals. Experimental animals also exhibited severe anemia and progressive loss of marrow-derived erythropoiesis. All of the FL-overexpressing animals, but none of the controls, died between 10 and 13 weeks posttransplantation. Upon histological examination, severe splenomegaly was noted, with progressive fibrosis and infiltration by abnormal lymphoreticular cells. Abnormal cell infiltration also occurred in other organ systems, including bone marrow and liver. In situ immunocytochemistry on liver sections showed that the cellular infiltrate was CD3+/NLDC145+/CD11c+, but B220- and F4/80-, suggestive of a mixed infiltrate of dendritic cells and activated T lymphocytes. Infiltration of splenic blood vessel perivascular spaces resulted in vascular compression and eventual occlusion, leading to splenic necrosis consistent with infarction. These results show that FL can affect both myeloid and lymphoid cell lineages in vivo and further demonstrate the potential toxicity of in vivo treatment with FL.

Animals↗

An analysis of the effects of combined treatment with rmGM-CSF and PEG-rHuMGDF in murine bone marrow transplant recipients.

We have studied the potential of combination growth factor treatment with GM-CSF and megakaryocyte growth and development factor (MGDF) to stimulate hematopoietic recovery in mice following bone marrow transplantation. More rapid recovery of neutrophils occurred in mice treated with recombinant murine (rm)GM-CSF plus pegylated recombinant human (PEG-rHu)MGDF than carrier treated controls, however this recovery was equivalent to the effect of treatment with rmGM-CSF alone. PEG-rHuMGDF stimulated a more rapid recovery of platelets with no effect on neutrophil recovery. At the two tested doses of rmGM-CSF (72 and 200 microg/kg/day) the platelet recovery was inferior to that in carrier treated mice. Also, the addition of rmGM-CSF to PEG-rHuMGDF had a dose-related negative impact on platelet recovery compared to PEG-rHuMGDF alone. These data suggest that the use of combination therapy in some clinical indications may lead to unexpected results. Furthermore, careful dosage studies may be necessary to identify the full potential of combined growth factors to obtain additive or synergistic effects on multilineage hematopoietic reconstitution in vivo.

Animals↗

Otorhinolaryngological training in Europe--a comparative study.

Postgraduate training in the United Kingdom is undergoing radical changes following the 'Calman Report'. Commissioned in response to a European Union (EU) Directive, this contained recommendations to allow reciprocal recognition of all EU trained specialists. We present the findings of a postal questionnaire sent to representatives of the European Federation of Oto-Rhino-Laryngological Societies and the otolaryngology professors of the UK and Ireland with a response rate of 62.7%. Aspects assessed included clinical and surgical experience, examinations, teaching, research, length, regulation and perception of training. The programmes share similar teaching and research experience but substantial differences exist in most other areas. The accredited UK trainee has a much wider clinical and surgical repertoire than those from the Continent. Greek trainees were trained to the lowest minimum standard. The requirements of a training system are largely determined by the level of clinical experience and surgical skill required by an independent specialist in a given country.

Europe↗

Confirmation of the presence of Mycobacterium tuberculosis and other mycobacteria in mycobacterial growth indicator tubes (MGIT) by multiplex strand displacement amplification.

Multiplex strand displacement amplification (mSDA) is capable of amplifying three distinct DNA sequences simultaneously. These include sequences present in most genera of mycobacteria, a sequence specific for Mycobacterium tuberculosis, and an internal control. mSDA was used to detect the presence of these target sequences in 154 (72 positive, 76 negative, and 6 failed) clinical specimens cultured in the mycobacterial growth indicator tube (MGIT) system. A wide variety of specimen types were processed and cultured. Once these cultures were deemed positive by MGIT fluorescence or were deemed negative after 8 weeks of incubation, MGIT culture aliquots were processed for mSDA analyses. A chemiluminescent microwell assay was used to detect the amplified products. The procedure was relatively simple and took less than 6 h to complete. The sensitivity of mSDA for detecting acid-fast bacilli was 96.4% compared to that of MGIT culture. Sensitivity and specificity were 97.2 and 96.1%, respectively, when all clinical criteria were considered. mSDA was shown to be a rapid and effective method for confirming the presence of M. tuberculosis and other mycobacteria in positive MGIT cultures.

Bacterial Typing Techniques↗

Megakaryocyte growth and development factor accelerates platelet recovery in peripheral blood progenitor cell transplant recipients.

We have investigated the potential of PEGylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF), a molecule related to thrombopoietin (mpl ligand or TPO) in minimizing the thrombocytopenia associated with hematopoietic ablation and peripheral blood progenitor cell (PBPC) transplant. Irradiated mice that received PBPC mobilized by PEG-rHuMGDF or granulocyte colony-stimulating factor (G-CSF) had a reduced number of thrombocytopenic days with platelets below 100 x 10(6) per mL of blood. Recipients of unmobilized PBPC had a 9 day thrombocytopenic phase which was shortened to 7 days if they were given granulocyte-macrophage colony-stimulating factor (GM-CSF)-mobilized PBPC. This was further reduced to 2 or 3 days of thrombocytopenia in recipients of G-CSF- or PEG-MGDF-mobilized PBPC. Despite our observation that PEG-rHuMGDF is a relatively modest stimulator of the mobilization of myeloid progenitors to the blood, MGDF-mobilized PBPC do effect accelerated recovery of platelets after transplantation. However, the most effective use of PEG-rHuMGDF is when it is given during the recovery phase after PBPC transplantation to hematopoietically ablated mice. Posttransplant treatment with PEG-rHuMGDF reduces thrombocytopenia to a single day or less, in recipients of most types of PBPC. Mice that were treated during the first 2 weeks after PBPC transplant with PEG-rHuMGDF had 1 thrombocytopenic day compared to 9 days in carrier-treated recipients of unmobilized PBPC and 2 to 3 days in carrier-treated recipients of the optimally mobilized PBPC from G-CSF or G-CSF/PEG-rHuMGDF treated donors. In groups where PEG-rHuMGDF was included in the mobilization protocol and used to treat recipients as well thrombocytopenia was effectively eliminated. These data show that PEG-rHuMGDF is a highly effective agent in eliminating the thrombocytopenia associated with PBPC transplantation.

Animals↗

The intracellular fate of apolipoprotein E is tau dependent and apoe allele-specific.

The apolipoprotein E (apoE) gene has been identified as a susceptibility gene for Alzheimer's disease, although the mechanism whereby apoE exerts this effect has not been determined. The aim of this study was to examine the intracellular fate of apoE and we demonstrate that in mammalian cells-transiently expressing tau and the low density lipoprotein receptor, apoE is taken up from cerebrospinal fluid (CSF) and apoE3, but not apoE4, reaches the cytoplasm. This isoform difference in the intracellular distribution of apoE is dependent upon tau expression and, although tau phosphorylation was not affected by apoE, these results suggest that apoE interactions with the cytoskeleton might be important in the molecular pathogenesis of Alzheimer's disease.

Alleles↗

Cardiac and regional hemodynamic interactions between halothane and nitric oxide synthase activity in dogs.

BACKGROUND: In vitro, halothane appears to affect the role played by nitric oxide in the regulation of vascular tone and cardiac function. In vivo, the results of the interactions between halothane and the nitric oxide pathway remain controversial. The authors investigated the effects of halothane on the cardiac and regional hemodynamic properties of N-methyl-L-arginine (NMA), a specific nitric oxide synthase inhibitor, in dogs. METHODS: Twenty-five dogs were chronically instrumented. Aortic pressure, the first derivative of left ventricular pressure, cardiac output, heart rate, and carotid, coronary, mesenteric, hepatic, portal and renal blood flows were continuously recorded. N-methyl-L-arginine was infused intravenously at 20 mg/kg over 1 min in awake dogs (n = 11) and in 1.2% halothane-anesthetized dogs (n = 10). As a control group, the remaining four dogs were studied awake and during 1.2% halothane for 2 h in the absence of NMA. RESULTS: In awake dogs, NMA produced a sustained pressor response (34%) and systemic vasoconstriction (40%) associated with a decrease in cardiac output (16%). Regional circulation changes included an immediate and transient increase in carotid (43%) and coronary (237%) blood flows and a subsequent decrease in carotid blood flow (25%). Hepatic and mesenteric blood flows also decreased, by 43% and 16%, respectively. Except for the coronary circulation, regional vascular resistance increased significantly. Halothane did not affect the pressor response to NMA but did blunt the cardiac output changes. Consequently, the systemic vasoconstriction after nitric oxide synthase inhibition was of shorter duration and of lesser magnitude during halothane anesthesia. Halothane also blunted the carotid, mesenteric, and renal vasoconstriction induced by NMA. Finally, in 1.2% halothane-anesthetized dogs, NMA induced a coronary vasoconstriction. CONCLUSIONS: Halothane minimally interferes with the systemic and regional hemodynamic consequences of nitric oxide synthase blockade. The nature and magnitude of the interaction depend on the territory in which they occur.

Anesthetics, Inhalation↗

The incidence of bacteria in middle ear effusions.

Otitis media with effusion (OME) is a common condition in paediatric ENT practice. Whilst surgical management is in many cases the mainstay of treatment for resistant OME, the use of antibiotics has been advocated by some authorities. Over one quarter of middle ear effusions analysed in this study contained potentially pathogenic bacteria. Antibiotics may be of value in the treatment of OME in these children.

Anti-Bacterial Agents↗