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Biomedical subjects

D Eastwood

Publications and source records attributed to D Eastwood.

At least 19 recordsLinked to original sources
PubMed2005

A low temperature method of isolating normal human articular chondrocytes.

OBJECTIVE: Numerous methods for isolation of human chondrocytes are reported in the literature, most based on isolation from animal cartilage. Normal human articular cartilage (NHAC) poses particular problems for isolating chondrocytes when compared to animal or other types of human cartilage: a hardy matrix, combined with few and friable chondrocytes makes isolation difficult. Our objective was to develop an efficient method of isolating chondrocytes from NHAC without jeopardising the viability of these cells. DESIGN: In this study we demonstrate that lowering the enzymatic digestion temperature to 27 degrees C increases cell yield and chondrocyte viability. We then optimised this low temperature isolation of chondrocytes from NHAC by comparing the relative efficacies of trypsin and protease and hyaluronidase in combination with different types of collagenase (I, II and XI) at releasing chondrocytes from their surrounding cartilaginous matrix. Enzymes were tested at different concentrations and for differing times. Outcome measures included determining the amount of cartilage digested, the number of viable chondrocytes isolated per gram of cartilage and cell adherence rates. CONCLUSIONS: From these set of experiments, the method that maximised cell yield without jeopardising cell viability proved to be a two stage process: pre-digestion step using trypsin for 15 min; followed by overnight digestion with a combination of two types of collagenase (types I and II) and at a lower temperature of 27 degrees C. This has resulted in an efficient and robust method of releasing chondrocytes from cartilage, without jeopardising the viability of these cells.

Aged↗
PubMed2005

The rate of marrow recovery and extent of donor engraftment following transplantation of ex vivo-expanded bone marrow cells are independently influenced by the cytokines used for expansion.

Successful stem cell transplantation depends on cell dose, and this is particularly true for placental/cord blood transplantation in which it has been clearly shown that both the success of engraftment as well as the speed of white cell and platelet recovery are dependent on the nucleated cell dose in the graft. Thus, if stem cell numbers could be increased, the speed as well as the likelihood of engraftment might be improved. We studied the effect of two different cytokine combinations--kit ligand (KL), interleukin-3 (IL-3), and Flt-3 ligand supplemented with thrombopoietin and IL-11 (combination 1) or granulocyte/macrophage colony-stimulating factor (GM-CSF) and G-CSF (combination 2)--for their ability to affect speed and extent of engraftment using limited numbers (5 x 10(4)) of murine bone marrow (BM) light-density (LD) cells or their progeny expanded ex vivo in the presence one or the other cytokine combination for 6 days. With combination 1, we found that speed of platelet recovery was enhanced, but at the expense of white blood cell (WBC) recovery and percent donor engraftment. Furthermore, the cytokine combination that best maintained donor engraftment, combination 2, did so at the expense of platelet recovery. In no case was percent donor engraftment improved over 5 x 10(4) unmanipulated LD BM cells. These results are consistent with the interpretation that immediate recovery of blood cells of different lineages and longterm donor engraftment are separate functions that can be influenced by the choice of cytokines used during the ex vivo expansion process.

Animals↗
PubMed2004

Prevalence of SAP gene defects in male patients diagnosed with common variable immunodeficiency.

The molecular basis of common variable immunodeficiency (CVID) is undefined, and diagnosis requires exclusion of other diseases including X-linked lymphoproliferative disease (XLP). This rare disorder of immunedysregulation presents typically after Epstein-Barr virus infection and results from defects in the SAP (SLAM associated protein) gene. SAP mutations have been found in a few patients diagnosed previously as CVID, suggesting that XLP may mimic CVID, but no large-scale analysis of CVID patients has been undertaken. We therefore analysed 60 male CVID and hypogammaglobulinaemic patients for abnormalities in SAP protein expression and for mutations in the SAP gene. In this study only one individual, who was found later to have an X-linked family history, was found to have a genomic mutation leading to abnormal SAP cDNA and protein expression. These results demonstrate that SAP defects are rarely observed in CVID patients. We suggest that routine screening of SAP may only be necessary in patients with other suggestive clinical features.

Adolescent↗
PubMed2003

Engraftment syndrome after autologous hematopoietic stem cell transplant supported by granulocyte-colony-stimulating factor (G-CSF) versus granulocyte-macrophage colony-stimulating factor (GM-CSF).

The engraftment syndrome (ES) is a phenomenon observed in some patients undergoing autologous hematopoietic stem cell transplant (AHSCT). ES is characterized by fever, rash, capillary leak, and pulmonary infiltrates occurring at the onset of engraftment. Prior studies have suggested that the administration of hematopoietic growth factors post-transplant results in the increased frequency of ES. However, the relative contribution of granulocyte colony-stimulating factor (G-CSF) vs granulocyte-macrophage colony-stimulating factor (GM-CSF) to the development of ES remains unknown. A total of 152 consecutive patients who were treated with high-dose chemotherapy and AHSCT supported by either G-CSF or GM-CSF were analyzed retrospectively. In all, 20 patients developed ES, an incidence of 13%. ES was seen more frequently in patients who received GM-CSF (GM-CSF 24% vs G-CSF 4%, p=0.0001). The highest incidence of ES was observed in breast cancer patients (42% of breast cancer patients; 70% of all ES cases). Comparison of the incidence of ES by the priming regimen used comprising either of the growth factors revealed no significant association (p=0.8224). This study demonstrates that the incidence of ES is higher using GM-CSF, particularly in patients with breast cancer. It suggests that it might be advantageous to administer only G-CSF in breast cancer patients undergoing AHSCT to reduce ES-related morbidity.

Adult↗
PubMed2001

Spectral tolerance determination for multivariate optical element design.

Recent reports from our laboratory have described a method for all-optical multivariate chemometric prediction from optical spectroscopy. The concept behind this optical approach is that a spectral pattern (a regression vector) can be encoded into the spectrum of an optical filter. The key element of these measurement schemes is the multivariate optical element (MOE), a multiwavelength interference-based spectral discriminator that is tied to the regression vector of a particular measurement. The fabrication of these MOEs is a complex operation that requires precise techniques. However, to date, no quantitative means of determining the allowable design/ manufacturing errors for MOEs has existed. The purpose of the present report is to show how the spectroscopy of a sample is used to define the accuracy with which MOEs must be designed and manufactured. We conclude this report with a general treatment of spectral tolerance and a worked example. The worked example is based on actual experimental measurements. We show how the spectral bandpass is defined operationally in a real problem, and how the statistics of the theoretical regression vector influence both the bandpass and the minimum tolerances. In the experimental example, we demonstrate that tolerances range continuously between 1 (totally tolerant) to approximately 10(-3) (0.1% T) in this problem.

Journal Article↗
PubMed2001

Factors affecting neutrophil and platelet reconstitution following T cell-depleted bone marrow transplantation: differential effects of growth factor type and role of CD34(+) cell dose.

We have performed univariate and multivariate analysis to determine the factors that affect the kinetics of neutrophil and platelet recovery in 546 recipients of T cell-depleted (TCD) marrow allografts. All patients received marrow depleted of mature CD3(+) T cells by complement-mediated lysis using T(10)B(9)-1A3 (n = 489) or Muromonab-Orthoclone OKT3 (n = 57) monoclonal antibodies. Neutrophil engraftment to 0.5 x 10(9)/1 and platelet engraftment to 20 x 10(9)/l were assessed as endpoints. Factors significantly affecting neutrophil or platelet engraftment in the univariate analysis included patient age, T cell dose, anti-thymocyte globulin use, gender, diagnosis at transplant, CMV serostatus, HLA mismatch, CD34 cell dose (n = 249), and growth factor use and type. These variables were included in the multivariate Cox proportional hazards regression model. The results showed that a faster rate of neutrophil engraftment was independently associated with CD34(+) cell dose > or = 5 x 10(6)/kg and most strongly with growth factor administration. Faster platelet engraftment was associated with transplantation for chronic leukemia, CD34(+) cell dose > or = 2 x 10(6)/kg, an HLA matched related donor, and the absence of growth factor use. G-CSF had a higher relative risk (RR) of enhancing neutrophil engraftment than GM-CSF and significantly delayed platelet engraftment. The combined use of G-CSF + GM-CSF was similar to G-CSF alone. The enhancing effect of G-CSF for neutrophil recovery was most striking for patients who engrafted to 0.5 x 10(9)/1 at or before day 12 (RR = 9.5, P < 0.0001) compared to patients who received no growth factor. Conversely, the delaying effect of G-CSF on platelet engraftment was strongest for patients engrafting on or before day 25 (RR = 0.4, P = 0.0004). Of the independent variables affecting engraftment kinetics in recipients of TCD marrow allografts only growth factor, and to a limited extent, CD34(+) cell dose can be controlled by the clinician. A higher CD34(+) cell dose enhances the rate of both neutrophil and platelet engraftment whereas for G-CSF the benefits of myeloid growth factor use in enhancing neutrophil recovery may be partly offset by a delay in platelet engraftment.

Adolescent↗
PubMed1998

Caudal epidurals: the whoosh test.

Caudal epidural injection is a simple procedure that carries a low risk of complications. The whoosh test (injection of air into the caudal epidural space with simultaneous auscultation over the thoracolumbar spine) has been recommended as an aid to correct needle placement. A 1-year prospective study, using fluoroscopic imaging to identify needle position, was conducted to compare the sensitivity and specificity of the whoosh test with that of clinical impression alone in assessing correct needle placement in the caudal space. Of 131 patients studied, correct needle placement was achieved in 121 on the first attempt (92%). Clinical impression alone had a sensitivity of 94% and a specificity of 20%. The whoosh test had a sensitivity of 80% and a specificity of 60%. The whoosh test is superior to clinical judgment in detecting incorrect caudal needle placement.

Air↗
PubMed1998

The impact of audit in a district general hospital on post-operative nausea and vomiting after major gynaecological surgery.

An audit of post-operative nausea and vomiting (PONV) was undertaken in 935 female patients who used morphine patient-controlled analgesia (PCA) for pain relief after major gynaecological operations in a district general hospital. We investigated retrospectively five different antiemetic policies and a reference group without policy from January 1993 to July 1995. The department's computerized audit system was used to analyse the observations. At the beginning of the audit, the incidence of nausea and vomiting was as high as 71.5%. But as a consequence of this audit, a departmental policy was adopted 3 years later, which had an incidence of PONV of only 51.7%. During this time the compliance with antiemetic protocols increased from 41% to 76%. There was significantly less PONV if an antiemetic protocol was followed (P = 0.002). This emphasizes the importance of corporate involvement in the development, formulation and evaluation of departmental protocols if compliance is to be high. We conclude that audit as a corporate effort improves the acceptance of departmental protocols. This reduces PONV significantly irrespective of the type of antiemetic drug used.

Analgesia, Patient-Controlled↗
PubMed1986

Bier's block--an improved technique.

A simple modification to the method of regional anaesthesia known as Bier's block is presented. This was applied to patients with Colles' fractures. In a controlled trial the technique produced anaesthesia more quickly than the other method.

Anesthesia, Conduction↗
PubMed1982

Incidence and microbiology of abdominal and pelvic abscess in Crohn's disease.

The incidence of abdominal and pelvic abscess is reported from a consecutive series of 111 patients undergoing 124 resections for Crohn's disease. Preoperative abscesses were found as a complication of Crohn's disease in 13 patients (10%) and 8 were clinically unsuspected. The majority of preoperative abscesses were confined to one site (localized to bowel, psoas sheath, pelvis, or in the abdominal wall). All preoperative abscesses occurred in patients requiring an emergency or urgent operation. Patients with a preoperative abscess had significantly lower serum albumin levels and significantly increased serum alkaline phosphatase values than the patients without an abscess. Postoperative abscesses occurred in 17 patients (14%) and six were multiple. Five of the postoperative abscesses occurred in patients who had had a preoperative abscess; these recurrent abscesses all presented 6-14 wk after an uncomplicated initial operation. The principal bacterial isolates were Escherichia coli (54%), Bacteroides fragilis (44%), enterococci (41%), and viridans streptococci (31%). The incidence of abscess was unrelated to the use of preoperative steroid therapy.

Abdomen↗
PubMed1977

Responses of enzymically isolated aleurone cells of oat to gibberellin a(3).

Oat (Avena sativa L.) aleurone layer cells (spheroplasts) were isolated by maceration of the aleurone layer with a mixture of commercially available cellulase and pectinase. About 20% of the cells present in intact layers were released as spheroplasts and 79 +/- 9% of the spheroplast population was viable as judged by methylene blue staining. The spheroplasts became disorganized in solutions containing less than 0.4 md-mannitol. When the spheroplasts were incubated for 48 hours, total activities of acid p-nitrophenyl phosphatase and acid proteinase increased and protein levels decreased. These changes were not effected by gibberellin A(3). Isolated aleurone layers incubated under the same conditions as the spheroplasts showed reduced responses to gibberellin A(3). It is concluded that the necessary presence of an osmoticum limits the value of spheroplasts as a system for studying the mechanism of action of gibberellin A(3) in the aleurone cell.

Journal Article↗