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Biomedical subjects

L A Wilson

Publications and source records attributed to L A Wilson.

198 records · Page 11Linked to original sources
PubMed1966

Normal serum cytotoxicity for P32-labeled smooth Enterobacteriaceae. I. Loss of label, death, and ultrastructural damage.

Spitznagel, John K. (University of North Carolina, Chapel Hill), and Lawrence A. Wilson. Normal serum cytotoxicity for P(32)-labeled smooth Enterobacteriaceae. I. Loss of label, death, and ultrastructural damage. J. Bacteriol. 91:393-400. 1966.-Metabolically labeled smooth Escherichia coli lost between 10 and 90% of P(32), compared with control suspensions, when suspended for 60 min in normal serum at 37 C. Similar results were obtained with several other genera of Enterobacteriaceae. The structural nature of the cell injury in E. coli was shown by electron microscopic examination of ultrathin sections. Complex injury which included all peripheral cell structures occurred and various degrees of cytoplasmic loss resulted. Injured bacteria retained their essential shape and did not collapse, evidently because sufficient rigid cell wall remained to prevent this. The cell damage was more like that reported with ethylenediaminetetraacetic acid lysozyme than that reported with growth in penicillin. Damage sufficient to cause rupture of peripheral structures was unique in that it involved only localized areas of cell wall and left large sections relatively intact. The loss of P(32) in the fresh normal serum was closely related to bacterial viability loss.

Animals↗
PubMedDate not supplied

Eye infections with herpes simplex viruses in neonates.

A newborn with severe ocular herpes simplex virus (HSV) type 2 infection acquired in utero is presented to exemplify problems in diagnosis and management. A review of 297 newborns with HSV type 1 or type 2 infection reveals that about one-fifth demonstrate ocular involvement including one or more of the following: microphatalmia, conjunctivitis, keratitis, chorioretinitis, optic neuritis and cataracts.

Adult↗
PubMedDate not supplied

Survey of animal livers for vitamin A content.

Retail samples of livers from calf (23), ox (18), lamb (17), pig (15), chicken (16) and turkey (1) were analysed to determine levels of vitamin A (all trans-retinol) and to aid assessment of the effects of using vitamin supplemented compound feedingstuffs for livestock. For comparison, 22 liver samples from lambs reared on diets not containing vitamin-supplemented compound feedingstuffs and four samples of liver from ox which had received supplemented feed but not during the last four months prior to slaughter were also analysed. The chosen method of analysis utilized saponification, solvent extraction and normal-phase high performance liquid chromatography with fluorescence detection. For all species analysed, the levels of vitamin A ranged from 10 to 1100 mg/kg, with all but seven at or below 400 mg/kg. For lamb and ox livers, the mean levels were 310 mg/kg and 200 mg/kg respectively for retail samples. The mean levels were 220 mg/kg (lamb) and 120 mg/kg (ox) in liver samples from animals fed controlled diets. The results are of the same order as those reported over recent years.

Animals↗
PubMedDate not supplied

A rapid capillary gas chromatographic method for the determination of propionic acid and propionates in bread and bread products.

A rapid method for the determination of propionic acid and propionates in bread and bread products is reported. The method employs solvent extraction, filtration and quantification by capillary gas chromatography using an internal standard. The limit of determination was 10 mg kg-1 propionic acid. The mean recovery rates for spiked bread samples were 108% at approximately 1,000 mg kg-1 (range of 106-110%, coefficient of variation 1.1%), 97% at approximately 2,000 mg kg-1 (range 96-98%, coefficient of variation 0.7%) and 98% at approximately 3,000 mg kg-1 (range of 97-100% and coefficient of variation of 1.1%). The method offers improved sensitivity, precision, chromatographic resolution and a wider sample analyte concentration range over a previously reported packed-column gas chromatographic method and has been applied to the analysis of bread, rolls, pitta breads and hamburger buns.

Bread↗
PubMedDate not supplied

Characterization of the principal colouring components of annatto using high performance liquid chromatography with photodiode-array detection.

The principal colouring components of the natural food colouring material annatto, the 9'-cis- and all-trans- isomers of bixin and norbixin, have been prepared in pure form. A reverse-phase HPLC method utilizing photodiode-array detection has been developed to enable their chromatographic and spectroscopic characterization. One minor component, a di-cis-isomer of norbixin has also been identified and characterized.

Carotenoids↗
PubMedDate not supplied

Survey of baked goods for propionic acid and propionates.

One hundred and thirty samples comprising bread (64), hamburger buns (33), pittas (16), cakes (9) and Christmas puddings (8) from various retail outlets in the UK, have been analysed for the preservative propionic acid. Only one sample of bread, two samples of hamburger buns and three samples of pitta contained propionic acid in excess of 1000 mg/kg (range 1110-2625 mg/kg). The three samples of pitta exceeded 2000 mg/kg of propionic acid, which is the maximum amount permitted for these products under a recently adopted European Union directive.

Bread↗
PubMedDate not supplied

SIV/DeltaB670 transmission across oral, colonic, and vaginal mucosae in the macaque.

The primary mode of human immunodeficiency virus (HIV) transmission worldwide is by exposure to the virus at vaginal, rectal, and oral mucosal surfaces. To understand HIV/simian immunodeficiency virus (SIV) transmission events at mucosal portals of entry, we used the SIV-macaque model to determine if mucosal surfaces function as barriers and select for particular viral genotypes. Rhesus macaques were inoculated intravaginally, intracolonically, intrarectally, or orally with the complex primary viral isolate SIV/DeltaB670. Peripheral blood mononuclear cells, collected within the first two weeks postinoculation, were cloned and sequenced from all infected macaques. In the majority of the animals analyzed, multiple genotypes were identified, independent of the route of infection. These findings suggest that the mucosal barrier may play a minor role in the genotypic selection observed during sexual transmission of HIV and emphasize the need to evaluate the viral diversity present within the mucosal secretions of chronically infected individuals.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

A technical analysis of an intraoperative radiation detection probe.

A technical evaluation was made of a commercial intraoperative radiation probe. This device utilizes a CsI (T1) scintillation detector and light pipe arrangement to count gamma radiation in vivo. After determining the optimal window and threshold setting, additional evaluations included linearity, distance response function, detector dead time, counter reproducibility, detector sensitivity, angular resolution, and energy resolution. Detector dead time (21.2 microseconds) was found to be characteristic of a nonparalysable system. Activity response for each radionuclide was linear (R = 0.99) both with and without collimation. Energy resolution, 25% at 210 keV, was not sufficient to separate the two photons (172 and 247 keV) emitted by 111In. Detector sensitivity was 1136 and 626 counts per s per microcurie of 111In and 99mTc, respectively. The mean effective distance from the face of the uncollimated probe to the crystal was determined to be 2.03 cm in air.

Antibodies↗
PubMedDate not supplied

Dosimetry of solid tumors.

Dosimetry data arising from a decade of radioimmunotherapy are summarized along with techniques utilized to arrive at the reported dose estimates. Generality of the MIRD methodology allows it to serve as a vehicle for the calculation of solid tumor dosimetry although several limitations exist. Nonstandard geometries of solid tumors will ultimately necessitate determination of absorbed fractions for the individual tumors. Several approaches currently under investigation are described. For reasons of practicality, solid tumor dosimetry estimates continue to use the assumption of homogeneous activity distribution in a source organ, accounting for either all radiation or only nonpenetrating radiation. As computation tools become available for incorporating inhomogeneous cellular level data, the currently used "average dose" as an index of tumor sterilization will likely be replaced with a statistical distribution based on the number of viable cells in the tumor volume. Estimates of a tumor control dose would be based upon a linear extension of dose coupled with a threshold dose for cell sterilization.

Humans↗
PubMedDate not supplied

Effect of blood pressure on prevalence of carotid atheroma.

In an attempt to elucidate the mechanism by which hypertension acts as a risk factor for major non-haemorrhagic stroke, its effect on the prevalence of carotid atheroma has been studied angiographically. The carotid angiograms of 269 patients with cerebral tumours have been reviewed for evidence of coincidental atheromatous change. The prevalence of signs of arterial disease at the carotid bifurcation proved to be greater amongst patients with an elevated casual blood pressure reading, though the effect was small and confined to subjects over 50 years of age. It is argued that other factors must contribute to the connection between hypertension and the risks of cerebral infarction.

Adult↗