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Biomedical subjects

D Hawes

Publications and source records attributed to D Hawes.

18 recordsLinked to original sources
PubMed2001

Detection of occult metastasis in patients with breast cancer.

The most important factor affecting the outcome of patients with invasive cancer is whether the tumor has spread, either regionally (to regional lymph nodes) or systemically. However, a proportion of patients with no evidence of systemic dissemination will develop recurrent disease after primary "curative" therapy. Clearly, these patients had occult systemic spread of disease that was undetectable by routinely employed methods (careful pathological, clinical, biochemical, and radiological evaluation). In addition, the success of adjuvant therapy is assumed to stem from its ability to eradicate occult metastases before they become clinically evident. Therefore, methods for the detection of occult metastases in patients with the earliest stage of cancer, i.e., prior to detection of metastases by any other clinical or pathological analysis, have received a great deal of attention.

Breast Neoplasms↗
PubMed2001

Occult metastasis.

The most important factor affecting the outcome of patients with invasive cancers is whether the tumor has spread, either regionally (to regional lymph nodes) or systemically. However, a proportion of patients with no evidence of systemic dissemination will develop recurrent disease after primary 'curative' therapy. Clearly, these patients had occult systemic spread of disease that was undetectable by methods routinely employed (careful pathological, clinical, biochemical and radiological evaluation). In addition, the success of adjuvant therapy is assumed to stem from its ability to eradicate occult metastases before they become clinically evident [1]. Therefore, methods for the detection of occult metastases in patients with the earliest stage of cancer, i.e., prior to detection of metastases by any other clinical or pathological analysis, have received a great deal of attention.

Bone Marrow↗
PubMed2001

Industrial scale-up of countercurrent chromatography: predictive scale-up.

This study describes how scale-up in countercurrent chromatography (CCC) can be simply predicted on a process scale CCC device by running a preliminary analytical-sized sample and having knowledge of the stationary-phase retention at scale-up conditions. Results have shown that simple experimentation can lead within a day to a process with the capability of several kilograms per day (tons per year) compound yield, and that this is feasible with benchtop CCC units.

Journal Article↗
PubMed2001

Occult metastases in patients with breast cancer.

The presence of occult metastases in the lymph nodes, bone marrow, or both of these compartments may not only define patients who are at higher risk for recurrence and death but also may identify biologically distinct mechanisms of tumor spread (e.g., lymphatic vs. vascular dissemination). Use of techniques to detect occult metastases may also allow the identification of a biologically important population of cells, i.e., those cells constituting the earliest metastatic population of tumor cells. Thus, techniques that identify occult metastases may be valuable in furthering our understanding of the events regulating tumor dissemination.

Bone Marrow Neoplasms↗
PubMed2000

Reliable and sensitive analysis of occult bone marrow metastases using automated cellular imaging.

The presence of occult bone marrow metastases (OM) has been reported to represent an important prognostic indicator for patients with operable breast cancer and other malignancies. Assaying for OM most commonly involves labor-intensive manual microscopic analysis. The present report examines the performance of a recently developed automated cellular image analysis system (ACIS; ChromaVision Medical Systems, Inc.) for identifying and enumerating OM in human breast cancer specimens. OM analysis was performed after immunocytochemical staining. Specimens used in this study consisted of normal bone marrow (n = 10), bone marrow spiked with carcinoma cells (n = 20), and bone marrow obtained from breast cancer patients (n = 39). The reproducibility of ACIS-assisted analysis for tumor cell detection was examined by having a pathologist evaluate montage images generated from multiple ACIS runs of five specimens. Independent ACIS-assisted analysis resulted in the detection of an identical number of tumor cells for each specimen in all instrument runs. Additional studies were performed to analyze OM from 39 breast cancer patients with two pathologists performing parallel analysis using either manual microscopy or ACIS-assisted analysis. In 17 of the 39 cases (44%), specimens were classified by the pathologist as positive for tumor cells after ACIS-assisted analysis, whereas the same pathologist failed to identify tumor cells on the same slides after analysis by manual microscopy. These studies indicate that the ACIS-assisted analysis provides excellent sensitivity and reproducibility for OM detection, relative to manual microscopy. Such performance may enable an improved approach for disease staging and stratifying patients for therapeutic intervention.

Bone Marrow Neoplasms↗
PubMed1999

Calcium-induced modification of protein conformation demonstrated by immunohistochemistry: What is the signal?

A recent study by Morgan et al. on the mechanism of the heating antigen retrieval (AR) has raised an interesting issue concerning calcium-induced modification of protein conformation demonstrated by immunohistochemistry (IHC). The current study is based on calcium-induced modification of thrombospondin (TSP) and Ki-67, as demonstrated by IHC using seven monoclonal antibodies (MAbs) to TSP and an MAb MIB1. Experiments were carried out on frozen tissue sections of bladder carcinoma and lymph node. Frozen sections were incubated with solutions of 50 mM CaCl2 and/or 10 mM EDTA at 4C overnight before formalin or acetone fixation for TSP and Ki-67, respectively. Sections were then fixed in 10% neutral buffered formalin or acetone before immunostaining. Seven MAbs to TSP, named Ab1 to 7 representing clone numbers of A4.1, D4.6, C6.7, A6.1, B5.2, A2.5, and HB8432, respectively, and MIB1 were utilized as primary antibodies. ABC was used as the detection system and AEC as the chromogen for immunohistochemical staining. An extracellular immunostaining pattern represented a positive result for TSP, and nuclear staining for MIB1. Frozen sections preincubated in 50 mM CaCl2 overnight at 4C showed significant loss of staining and/or altered staining pattern for six of the seven antibodies to TSP and MIB1 compared to positive controls not exposed to CaCl2. Lack of immunostaining of TSP and MIB1 attributable to exposure to CaCl2 could be partially recovered by incubating the frozen sections in EDTA. Calcium-induced modification of protein structure was demonstrated more than 10 years ago on the basis of immunochemical techniques. In this study, similar calcium-induced modification of protein was detectable by IHC in frozen tissue sections, suggesting that calcium-induced modification of protein structure may occur independently of fixation-induced modification. The fact that calcium binding may affect IHC staining is not surprising in view of the fact that antibody/antigen interactions are protein structure-dependent. However, in this experiment the change occurred before and independent of formalin fixation and does not necessarily imply a role for calcium in AR. There may be a valuable role for the use of chemical modification in visualization of protein structure changes in tissue sections by IHC. (J Histochem Cytochem 47:463-469, 1999)

Calcium↗
PubMed1998

Detection of occult metastases in lung carcinomas: progress and implications for lung cancer staging.

The ability to detect occult regional and systemic metastases in patients with operable lung carcinoma could have a significant impact on the management of the disease. Here, we review the literature, including studies from our own laboratory, regarding the clinical significance of the presence of occult metastases in patients with lung cancer. The accumulated evidence strongly suggests that the detection of occult regional and systemic metastases is an important predictor of disease progression. The use of this method should be considered in the future design of lung cancer clinical trials, at the very least. The detection of occult metastases should have an impact on lung cancer management; to reflect this, we propose a change in the TNM staging system to indicate the presence or absence of occult regional (lymph node) and systemic (bone marrow) metastases. The proposed change is TNnMm, where n and m are occult nodal and bone marrow metastases status.

Bone Marrow Neoplasms↗
PubMed1992

Specific genetic analysis of microscopic tissue after selective ultraviolet radiation fractionation and the polymerase chain reaction.

A method using selective ultraviolet radiation fractionation followed by polymerase chain reaction (PCR) can analyze specific cell subsets present on a microscope section. Direct ultraviolet radiation of fixed and stained tissue sections prevents subsequent amplification by PCR. An "umbrella" or dot placed physically over small numbers of pure cell populations selected by microscopic examination protects these cells from the ultraviolet inactivation. The DNA in these protected cells can be specifically amplified while no signal is derived from the unprotected surrounding cells. Specific amplification was demonstrated by detecting human papillomavirus sequences only if infected cells were protected. Similarly, loss of heterozygosity at the p53 locus was documented by selective dotting of normal or tumor cells. The method allows the specific and sensitive molecular genetic analysis of small numbers of cells histologically identified and selected under the microscope.

Base Sequence↗
PubMed1988

Clinical spectrum and outcome of neonatal convulsions.

The clinical spectrum and outcome of neonatal convulsions within an obstetric hospital population were reviewed for the 5 years, 1978-82, inclusive. There were 156 convulsing neonates managed at the Mater Mothers Hospital (110 inborn, 46 outborn). The incidence of early neonatal convulsions for inborn babies was 3.0/1000 live births. Antenatal and perinatal risk factors were compared between the 156 convulsing infants and the 36,082 infants born during the same period who did not convulse. The leading risk factors for convulsions were prematurity, intra-uterine growth retardation, low 5 min Apgar score, pre-eclampsia, antepartum haemorrhage, twin pregnancy and breech presentation. The predominant seizure type was tonic in 28.6%, multifocal clonic in 27.2%, subtle in 18.4%, myoclonic in 15.0% and focal clonic in 8.8%. Mortality (31%) and long-term disability (43%) rates were high. Tonic seizures had the highest mortality and morbidity. Throughout the duration of the study period infants received increasingly thorough investigation. Causative factors were determined in 95% of convulsing infants, most frequent being hypoxic-ischaemic encephalopathy (40.3%) and cerebroventricular haemorrhage (30.5%). Follow-up data on 99 of the 107 survivors (93%) revealed severe disability in 25, moderate disability in eight and mild disability in 10. A poor long-term prognosis was associated with prolonged convulsions, tonic and multifocal clonic convulsions, convulsions due to asphyxia and cerebroventricular haemorrhage and an abnormal neurological examination at discharge.

Humans↗
PubMedDate not supplied

Phantom for calibration of preoperative imaging modalities in endoluminal stent-graft repair of aortic aneurysms.

PURPOSE: Successful deployment of an endoluminal prosthesis for repair of an abdominal aortic aneurysm (AAA) is critically dependent on accurate preoperative assessment of aneurysm morphology with use of such modalities as contrast aortography (CA), spiral computed tomography (CT), magnetic resonance (MR) imaging, and intravascular ultrasonography (IVUWS). The authors describe a new phantom that could be used both to calibrate these four imaging modalities and to determine which imaging technique(s) is (are) best for preoperative AAA sizing. MATERIALS AND METHODS: A life-sized AAA model was constructed of silicone elastomers with luminal access ports for introduction of contrast media and catheters. Contrast material-filled rings were positioned circumferentially along the length of the model as reference points for dimension measurements. The modalities were compared to each other relative to the actual dimensions of the model, as determined at its construction. RESULTS: In this pilot study, all modalities were relatively similar in their ability to measure the dimensions of the AAA model. Length measurements accounted for most of the interinstitutional and interobserver variability. MR imaging had the least variability. CONCLUSIONS: The authors developed a new phantom that can be imaged successfully with CA, CT, MR imaging, and IVUS in repetitive, reproducible fashion. Structural refinements and future larger scale, statistically significant evaluations of such models should establish this as a useful adjunct in multicenter endoluminal stent-graft trials to allow calibration of imaging modalities and to determine which modality or modalities is (are) best for preoperative AAA sizing.

Aortic Aneurysm, Abdominal↗
PubMedDate not supplied

Epstein-Barr virus-associated gastric adenocarcinoma among Japanese Americans in Hawaii.

This study confirms the observation that some gastric adenocarcinomas contain Epstein-Barr viral (EBV) sequences in their carcinoma cells. EBV sequences were detected by polymerase chain reaction and in situ hybridization in the tumors of 19 of 187 (10.2%) Japanese-American men and women living in Hawaii. The EBV-associated gastric cancers were more frequently present in men than in women: 14 of 99 (14.3%) men versus 5 of 88 (5.7%) women (P = 0.046). EBV type A was found in 17 of the 19 EBV-associated cancers, a finding consistent with the type A predominance in Japanese populations. Intestinal and diffuse-type tumors were both EBV-positive, and moderate to marked inflammation was usually present. The virus was not found in adjacent normal nonneoplastic mucosal cells or in mucosa showing intestinal metaplasia. EBV-associated tumors were found at stages 1 or 2 in 53% of cases, compared with 36% of the EBV-negative cancers (P = 0.13). The presence of EBV did not appear to influence survival. The relatively high incidence of gastric cancer compared to other EBV-associated tumors makes EBV-associated gastric cancer potentially one of the most common EBV-related tumors in the United States.

Adenocarcinoma↗