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E M White

Publications and source records attributed to E M White.

At least 19 recordsLinked to original sources
PubMed2006

The effect of elevated hydrostatic pressure on the spectral absorption of deep-sea fish visual pigments.

The effect of hydrostatic pressure (0.1-54 MPa, equivalent to pressures experienced by fish from the ocean's surface to depths of ca. 5,400 m) on visual pigment absorption spectra was investigated for rod visual pigments extracted from the retinae of 12 species of deep-sea fish of diverse phylogeny and habitat. The wavelength of peak absorption (lambda(max)) was shifted to longer wavelengths by an average of 1.35 nm at 40 MPa (a pressure approximately equivalent to average ocean depth) relative to measurements made at one atmosphere (ca. 0.1 MPa), but with little evidence of a change in absorbance at the lambda(max). We conclude that previous lambda(max) measurements of deep-sea fish visual pigments, made at a pressure close to 0.1 MPa, provide a good indication of lambda(max) values at higher pressures when considering the ecology of vision in the deep-sea. Although not affecting the spectral sensitivity of the animal to any important degree, the observed shift in lambda(max) may be of interest in the context of understanding opsin-chromophore interaction and spectral tuning of visual pigments.

Animals↗
PubMed2000

Preliminary report on the results of the second phase of a round- robin endotoxin assay study using cotton dust.

In an on-going endotoxin assay study, a two-part interlaboratory endotoxin assay study has been completed. The purpose of the study was to compare the variation in assay results between different laboratories, and, if the variation was high, to see if a common protocol would reduce the variation. In both parts of the study, membrane filters laden with the same approximate amount and type of cotton dust were sent for analysis to laboratories that "routinely" perform endotoxin analyses. First, each of these laboratories performed the analysis using the methodology common to its laboratory. In the second part of the study, membrane filters with cotton dust were again sent to the same laboratories where the analyses were performed as before but with a common extraction protocol. The preliminary results from the first phase of the study have been collected and showed that intra-laboratory variations were small, but large and significant interlaboratory variation was observed. The results were reported elsewhere. The preliminary results from the second part of the study consisting of the data currently collected are presented here. Again, intra-laboratory variations were small, but, also again, large and significant inter-laboratory variation was observed. However, in this part of the study, the range between the highest and lowest average results was narrower than in the first part of the study. Influence of the assay kit type was examined. The variation within assay kit type was small but significant differences in results were observed between assay kit types. The findings suggest that endotoxin concentration in samples can be ranked within laboratories, but not necessarily between laboratories. However, some of the variation between laboratories has been reduced by a common extraction protocol which suggests the possibility of further standardization that may lead to better comparability between laboratories.

Air Pollution, Indoor↗
PubMed1996

Validation of retroviral detection for rodent cell-derived products and gene therapy applications.

The availability of sensitive assays for detecting infectious murine retroviruses has become critical for the development and acceptance of a number of biopharmaceuticals, including monoclonal antibody-derived products and gene therapy vectors. Comparative studies demonstrated that the PG4 S+L- retrovirus infectivity test routinely yields higher titres than the mink cell test for xenotropic, amphotrophic and MCF murine retroviruses. A validation study for the PG4 S+L- assay demonstrated very good linearity (r2 of 0.95 to 0.99), reproducibility within a study (+/-0.35 log10 units), and precision between tests (+/-0.45 log10 units). Interference (or selectivity) in the presence of a non-specific antibody was insignificant (less than 0.2 log10 units). Sensitivity levels established from measurements as virus titres approach zero demonstrated a threshold value of 2-3 focus forming units (FFU)/ml. Two methods for increasing assay sensitivity were used including: (i) increased product samplings combined with a Poisson distribution analysis, and (ii) a 14-day co-cultivation with Mus dunni cells. Each of these methods was shown to increase sensitivity by at least one log10 unit. Murine retroviruses may also be detected by a less sensitive immunofluorescence assay (IFA) using specific monoclonal antibodies; this assay is essential for detecting certain recombinant ecotropic MuLVs. In summary, murine retroviral detection ranked by sensitivity is mink S+L- < IFA with monoclonal antibodies < PG4 S+L- < Mus dunni co-cultivation followed by PG4 S+L-.

Animals↗
PubMed1995

Body mass index centile charts to assess fatness of British children.

Body mass index (BMI) relates weight to height and reflects the shape of a child, but because of age dependency it has not been used conventionally for the estimation of fatness in children. From measurements of Tayside children (n = 34,533) centile charts were constructed for BMI (wt/ht2) from the raw data of height and weight, using Cole's LMS method for normalised growth standards. These data were compared with the only available European BMI charts published from data of French children obtained over a period of 24 years from 1956-79. British children appear to be 'fatter'. Within a subgroup (n = 445) the BMI values were correlated with estimations of body fat, for boys and girls, from skinfold thickness (r = 0.8 and 0.81) and bioelectrical impedance (r = 0.65 and 0.7). The limits of acceptable BMI have yet to be defined.

Adipose Tissue↗
PubMed1995

Cross sectional stature and weight reference curves for the UK, 1990.

The current reference curves of stature and weight for the UK were first published in 1966 and have been used ever since despite increasing concern that they may not adequately describe the growth of present day British children. Using current data from seven sources new reference curves have been estimated from birth to 20 years for children in 1990. The great majority of the data are nationally representative. The analysis used Cole's LMS method and has produced efficient estimates of the conventional centiles and gives a good fit to the data. These curves differ from the currently used curves at key ages for both stature and weight. In view of the concerns expressed about the current curves and the differences between them and the new curves, it is proposed that the curves presented here should be adopted as the new UK reference curves.

Adolescent↗
PubMed1995

Allograft safety: viral inactivation with bone demineralization.

A study was performed to validate the effectiveness of a bone demineralization process with respect to its inactivation of viruses. The viruses selected for study included human immunodeficiency virus (HIV), duck hepatitis B virus (a model for human hepatitis B), bovine viral diarrheal virus (a model for human hepatitis C), human cytomegalovirus, and human poliovirus (a model for small nonenveloped viruses, e.g., hepatitis A). This study was performed in compliance with Good Laboratory Practice regulations using validation methodology similar to that used to ensure the safety of blood derivatives and other products. Use of the bone demineralization process described in this report resulted in a reduction in infectivity of greater than one million (10(6)) for all viruses and as much as one trillion (10(12)) for the poliovirus.

Bone Substitutes↗
PubMed1994

Passive hepatic congestion: cross-sectional imaging features.

Passive hepatic congestion is caused by stasis of blood within the liver parenchyma due to compromise of hepatic venous drainage. It is a common complication of congestive heart failure and constrictive pericarditis, wherein elevated central venous pressure is directly transmitted from the right atrium to the hepatic veins because of their close anatomic relationship (Fig. 1). The liver becomes tensely swollen as the hepatic sinusoids dilate and engorge to accommodate the backflow of blood. A variety of structural and functional hepatic derangements develop that have distinctive appearances on sonograms, CT scans, and MR images.

Female↗
PubMed1994

Magnetic resonance imaging in synovial disorders and arthropathy of the knee.

The ability of MR imaging to demonstrate articular cartilage, the synovium, and the adjacent bone greatly assists in the diagnosis and treatment of synovial disorders and a variety of arthropathies of the knee. The use of specific pulse sequences and intravenous contrast material can improve the performance of MR imaging of the knee in patients with synovitis, arthritis, or synovial-based neoplasms.

Adult↗
PubMed1993

Carcinoma arising in urinary bladder diverticula: imaging findings in six patients.

OBJECTIVE: Carcinoma arising within urinary bladder diverticula has a poorer prognosis than do neoplasms that originate within the main bladder lumen as a result of early transmural tumor infiltration. Imaging plays an important role in diagnosing and staging the disease. We describe the radiologic findings in six patients with pathologically proved diverticular carcinomas. MATERIALS AND METHODS: We reviewed the records of six patients who had radiologic examinations and surgically confirmed vesical diverticular carcinomas. The examinations included excretory urography in three patients, cystography in three patients, CT in five patients, and MR imaging in one patient. All patients had hematuria. Five patients had transitional cell carcinoma, and one patient had squamous cell carcinoma. RESULTS: Three of the tumors manifested as an intraluminal filling defect within a bladder diverticulum on excretory urograms or cystograms. In one patient, CT scans showed a concentric soft-tissue tumor in a diverticular neck. Correlative cystograms showed only smooth narrowing in this area. CT and MR imaging showed a tumor within a large diverticulum, which was not visualized on cystograms because of obstruction at the diverticular orifice. CONCLUSION: Imaging plays an important role in identifying bladder diverticula as a potential site of occult neoplasm.

Aged↗
PubMed1993

Hepatitis B viral clearance studies using duck virus model.

We have shown data to suggest that the in vivo duck hepatitis B virus system represents an excellent animal model system for the study of hepatitis B virus. Because of the similarity of DHBV to human HBV (including comparable results in virus inactivation studies), the high level of sensitivity of the DHBV assay, and the rapidity, ease, and relative low cost of obtaining results, we propose that the in vivo DHBV titration system be used as a model for human HBV in process validation studies. Data generated in such validation studies have, in fact, been submitted by a number of blood products manufacturers to the U.S. F.D.A. in support of IND applications.

Animals↗
PubMed1992

Appendices epiploicae of the colon: radiologic and pathologic features.

Appendices epiploicae are adipose structures protruding from the serosal surface of the colon. They can be seen with abdominal radiography and cross-sectional imaging if the colonic wall is surrounded by intraperitoneal contrast material, ascites, or blood. Normal appendices epiploicae appear as lobulated masses of pericolic fat, usually 2-5 cm long and 1-2 cm thick. Their enlargement, deformity, or altered radiopacity may result from various pathologic processes that can originate locally or extend from adjacent viscera. In a series of 22 cases, appendices epiploicae were affected by spontaneous torsion and hemorrhagic infarct, calcification due to aseptic fat necrosis, primary or secondary inflammation, enlargement by lipomas or metastases, and incarceration in hernias. Disorders of appendices epiploicae are often manifested by nonspecific clinical signs and symptoms (eg, torsion is often mistaken for appendicitis or diverticulitis). These entities should be included in the differential diagnosis of any unexplained abdominal pain or pericolic lesions in adults.

Adipose Tissue↗
PubMed1992

Imaging manifestations of pleural tumors.

Although radiologic assessment of pleural tumors may be accomplished with several imaging modalities, the standard noninvasive techniques include chest radiography and computed tomography (CT). These examinations may be supplemented with magnetic resonance imaging and occasionally with ultrasound. Depending on the location, size, and underlying histologic features, pleural tumors may produce a spectrum of findings. CT is particularly useful in defining the location and extent of these masses. The authors present a review of basic pleural anatomy and imaging features of both benign and malignant pleural neoplasms. The pleural may be involved by one of several primary or metastatic tumors. Specific cell types are diffuse malignant mesothelioma (the most common plain radiographic findings are unilateral pleural effusion and pleural thickening), localized fibrous tumor (circumscribed, spherical or ovoid, noncalcified lesions arising in the pleural surface), metastatic disease (radiographic findings may mimic those of malignant mesothelioma), and uncommon neoplasms including thymoma and lymphoma. Among these various pleural tumors, metastatic disease represents the most common neoplasm.

Humans↗
PubMed1992

Practical screening priorities for hearing impairment among children in developing countries.

Routine screening for hearing impairment in childhood is now widespread in industrial countries, although there is considerable controversy over the most efficient techniques and procedures. In most developing countries, however, routine screening programmes for hearing impairment do not currently exist. The problems involved in implementing screening programmes in developing and industrial countries are very different, and in selecting screening procedures for a particular population the following factors have to be taken into consideration: the environmental test conditions; the availability of resources for equipment and the training of testers; the local attitudes towards disability; the level of hearing impairment that may cause handicaps; and the major types of pathology causing hearing impairment. We suggest that in developing countries children should be screened at school entry using a simple field audiometer and that the external ear be inspected for the presence of a discharge. There is an urgent need to develop reliable and simple screening procedures for infants and young children; where possible, all children should be screened for severe or significant hearing impairment before the age of 2 years. No screening should, however, be implemented until appropriate follow-up services are available.

Acoustic Impedance Tests↗
PubMed1990

Conservation of intron position indicates separation of major and variant H2As is an early event in the evolution of eukaryotes.

Genomic clones of Drosophila and Tetrahymena histone H2A variants were isolated using the corresponding cDNA clones (van Daal et al. 1988; White et al. 1988). The site corresponding to the initiation of transcription was defined by primer extension for both Drosophila and Tetrahymena genomic sequences. The sequences of the genomic clones revealed the presence of introns in each of the genes. The Drosophila gene has three introns: one immediately following the initiation codon, one between amino acids 26 and 27 (gln and phe), and one between amino acids 64 and 65 (glu and val). The Tetrahymena gene has two introns, the positions of which are identical to the first two introns of the Drosophila gene. The chicken H2A.F variant gene has been recently sequenced and it contains four introns (Dalton et al. 1989). The first three of these are in the same positions as the introns in the Drosophila gene. The fourth intron interrupts amino acid 108 (gly). In all cases the sizes and the sequences of the introns are divergent. However, the fact that they are in conserved positions suggests that at least two of the introns were present in the ancestral gene. A phylogenetic tree constructed from the sequences of the variant and major cell cycle-regulated histone H2A proteins from several species indicates that the H2A variant proteins are evolutionarily separate and distinct from the major cell cycle-regulated histone H2A proteins. The ancestral H2A gene must have duplicated and diverged before fungi and ciliates diverged from the rest of the eukaryote lineage. In addition, it appears that the variant histone H2A proteins analyzed here are more conserved than the major histone H2A proteins.

Amino Acid Sequence↗
PubMed1989

Nucleus-specific and temporally restricted localization of proteins in Tetrahymena macronuclei and micronuclei.

Labeled nuclear proteins were microinjected into the cytoplasm of Tetrahymena thermophila. Macronuclear H1, calf thymus H1, and the SV40 large T antigen nuclear localization signal linked to BSA accumulated specifically in macronuclei, even if cells were in micronuclear S phase or were nonreplicating. The way in which histone H4 localized to either the macronucleus or the micronucleus suggested that it accumulates in whichever nucleus is replicating. The inability of the micronucleus to accumulate Tetrahymena H1 or heterologous nuclear proteins, even at a period in the cell cycle when it is accumulating H4, suggests that it has a specialized transport system. These studies demonstrate that although the mechanism for localizing proteins to nuclei is highly conserved among eukaryotes, it can differ between two porecontaining nuclei lying in the same cytoplasm.

Animals↗
PubMed1989

Infected abdominal tumors: percutaneous catheter drainage.

Sixteen patients underwent percutaneous catheter drainage of infected primary (n = 9) or metastatic (n = 7) abdominal tumors. Twelve of the patients improved clinically, as evidenced by defervescence and decrease or normalization of leukocytosis. Four patients did not respond to catheter drainage and required surgery. Three of the twelve who improved underwent operations for attempts at surgical cure or debulking of tumor volume despite an initial "good" response to percutaneous drainage. Of the nine patients who did not undergo surgery after percutaneous drainage, four underwent catheter removal after 5 weeks of drainage and had no recurrence of infection, two remained alive with the catheter in place up to 8 months and 1 year after drainage, and two died with the catheter in place. One patient had the catheter removed inadvertently after 3 weeks of drainage and had recurrences that required replacement of the catheter until his death. The major differences between drainage of necrotic tumors and drainage of standard abscesses were the need for surgery in the majority of the cases and the fact that patients needed the catheters for continued palliation until their death.

Abdominal Neoplasms↗
PubMed1989

Adapting milieu approaches to acute inpatient care for schizophrenic patients.

Classic therapeutic community or milieu therapy techniques are not applicable in many contemporary acute-treatment settings, which emphasize crisis intervention, short stays, psychotropic medication, and cost containment. However, milieu techniques can be integrated with an understanding of biological and psychosocial factors to provide a framework for the acute, short-term treatment of schizophrenic patients. After reviewing recent biological and psychosocial research, the authors outline three principles for incorporating such research with milieu techniques: creating a holding environment, developing a graduated therapeutic program, and focusing on common patient needs. Application of these principles in a short-stay setting will provide an intensely supportive treatment environment that allows the use of many different therapies and modulates stresses on staff.

Acute Disease↗