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Biomedical subjects

D B Wilson

Publications and source records attributed to D B Wilson.

At least 397 records · Page 22Linked to original sources
PubMed1967

Mixed leukocyte reactions and histocompatibility in rats.

Mixed leukocyte culture tests have been carried out on two hetero geneous but genetically defined backcross populations of rats to determine whether the reactions observed can provide the basis for histocompatibility matching. The experiments were designed so that only-one-way reactions could occur. Only when the donors of individual leukocyte mixtures differed at the important Ag-B histocompatibility locus was there any in vitro reactivity, and differences at this locus were invariably associated with the prompt rejection of skin homografts. Determination of compatibility at this locus proved to be important in that it facilitated the prolongation of survival of skin homografts by immunosuppressive therapy.

Animals↗
PubMedDate not supplied

The effect of sugar on behavior or cognition in children. A meta-analysis.

OBJECTIVE: To examine the effects of sugar on the behavior or cognition of children by using meta-analytic techniques on reported studies. DATA SOURCES: Studies were identified through a literature search of the MEDLINE and PsychINFO databases and the authors' files using sugar, sucrose, and attention deficit disorder as the search terms. STUDY SELECTION: Studies were required to (1) intervene by having the subjects consume a known quantity of sugar, (2) use a placebo (artificial sweetener) condition (3) blind the subjects, parents, and research staff to the conditions; and (4) report statistics that could be used to compute the dependent measures effect sizes. DATA EXTRACTION: Variables included publication year, study setting, subject type and number, gender, age, sugar and placebo type and dose, prior dietary condition, measurement construct, means and SDs for the sugar and placebo conditions, and direction of effect. DATA SYNTHESIS: Sixteen reports met the inclusion criteria for a total of 23 within-subject design studies. The weighted mean effect size and related statistics for each of the 14 measurement constructs revealed that although the range for these means was from -0.14 for direct observations and up to +0.30 for academic tests, the 95% confidence interval for all 14 mean effect sizes included 0. CONCLUSION: The meta-analytic synthesis of the studies to date found that sugar does not affect the behavior or cognitive performance of children. The strong belief of parents may be due to expectancy and common association. However, a small effect of sugar or effects on subsets of children cannot be ruled out.

Adolescent↗
PubMedDate not supplied

Embryonic development of the head and neck: part 2, the branchial region.

The embryology of the branchial (pharyngeal) region is reviewed in terms of the embryonic pharynx, branchial apparatus and derivatives, tongue, larynx, and trachea. Derivatives of the branchial pouches, grooves (clefts), and arches are analyzed in relation to each other and to the first arch syndrome. Other common head and neck defects attributable to abnormal development of the branchial region are also discussed, particularly those defects involving the incomplete degeneration or the abnormal migration of branchial tissues.

Branchial Region↗
PubMedDate not supplied

Embryonic development of the head and neck: Part 3, The face.

The embryology of the face is presented with respect to changes affecting the mandible, maxilla, upper and lower lips, palate, nose, and oral cavity. The embryonic development of the teeth and salivary glands is also included. Various facial clefts, including cleft lip and cleft palate, are discussed, in addition to some congenital anomalies affecting the nose and oral cavity.

Cleft Lip↗
PubMedDate not supplied

Embryonic development of the head and neck: part 4, organs of special sense.

A synopsis of the embryonic development of the eye, the ear, and the olfactory organ and taste buds is presented. The eye is discussed in terms of the sensory and nonsensory protions of the eyeball and of such associated structures as the extrinsic eye muscles, eyelids, conjuctiva, and lacrimal apparatus. The embryology of the internal, middle, and external ear is reviewed, as well as positional changes of both the eye and ear relative to other sturctures of the head and neck. Various congenital defects affecting the eye and ear are also discussed.

Ear↗
PubMedDate not supplied

Embryonic development of the head and neck: part 5, the brain and cranium.

The development of the brain is presented with respect to closure of the neural tube, the formation of the five vesicles of the brain and their derivatives, and the cranial flexures. The cranial nerves, meninges, choroid plexuses, and cerebral vasculature are also discussed. The origin and ossification of the bony elements of the head and neck, including the neurocranium, viscerocranium, and cervical vertebrae, are described, as well as major congenital defects of the brain and the cranium.

Brain↗
PubMedDate not supplied

Escherichia coli host cell modifications in continuous culture affecting heterologous protein overproduction: a population dynamics study.

There are many published studies of plasmid segregational instability in Escherichia coli in the literature. However, the formation of plasmid-free segregants can be controlled by the addition of selective chemical agents like antibiotics. This solution has become commonplace in both the laboratory and industry. On the other hand, host cell modifications, which result in low production of plasmid-encoded protein and lead to loss of culture productivity, have not been adequately addressed. Continuous culture of an inducible (ptac) Escherichia coli vector containing strain, RB791(pKN), was characterized by strong dynamic changes in the cell population and product (beta-lactamase) expression. Long-term cultivation resulted in the loss of high-level production of beta-lactamase. Loss of productivity was not due to the formation of plasmid-free cells or structural modifications to the plasmid; instead, continuous operation resulted in a culture dominated by irreversibly altered, low-producing cells. Two distinct classes of lac- mutants which inhibited induction were identified (Y- and I(s)).

Chromosomes, Bacterial↗
PubMedDate not supplied

Effects of plasmid copy number and runaway plasmid replication on overproduction and excretion of beta-lactamase from Escherichia coli.

Runaway plasmid replication can be used to increase target gene dosage and thereby overproduce proteins within the bacterium Escherichia coli. However, the presence of excessive plasmid DNA often alters normal cell functions. High copy number plasmids with strong promoters place a severe metabolic burden on the cell, causing a decreased specific growth rate and changes in cell physiology. Induction of beta-lactamase synthesis from the tac promoter on plasmid pKN causes runaway plasmid replication and excretion of beta-lactamase. Runaway plasmid replication results from readthrough of tac promoter transcripts into the replication region of the plasmid. Both high plasmid copy numbers and a strong promoter (tac) are necessary to achieve the level of overproduction necessary for excretion of beta-lactamase, but high-level target protein synthesis is detrimental to the cell. A derivative of pKN which is more easily regulated was constructed by adding the lacI gene to the plasmid.

DNA Replication↗
PubMedDate not supplied

Hg2+ removal by genetically engineered Escherichia coli in a hollow fiber bioreactor.

Escherichia coli cells engineered to express an Hg2+ transport system and metallothionein accumulated Hg2+ effectively over a concentration range of 0.2-4 mg/L in batch systems. Bioaccumulation was selective against other metal ions and resistant to changes in ambient conditions such as pH, ionic strength, and the presence of common metal chelators or complexing agents (Chen, S.-L.; Wilson, D. B. Appl. Environ. Microbiol. 1997, 63, 2442-2445; Biodegradation 1997, 8, 97-103). Here we report the characterization of the bioaccumulation system based on its kinetics and an isotherm. Bioaccumulation was rapid and followed Michaelis-Menten kinetics. A hollow fiber bioreactor was constructed to retain the genetically engineered cells. The bioreactor was capable of removing and recovering Hg2+ effectively at low concentrations, reducing a 2 mg/L solution to about 5 microgram/L. A mathematical equation that quantitatively described Hg2+ removal by the bioreactor provides a basis for the optimization and extrapolation of the bioreactor. The genetically engineered E. colicells and the bioreactor system have excellent properties for bioremediation of Hg2+-contaminated environments.

Bioreactors↗
PubMedDate not supplied

Anti-idiotypic cytotoxic T cells in rats with graft-versus-host disease.

Transfer of parental strain T lymphocytes into F1 hybrid rats differing with respect to gene products of the major histocompatibility complex (MHC) causes a graft-versus-host (GvH) reaction. This reaction results from recognition of host allogeneic MHC gene products by specific clones of donor T cells. When given systemically in sufficient numbers, these donor T cells cause a progressive, generally fatal wasting syndrome, an early feature of which includes extensive splenomegaly. A more local, non-fatal GvH reaction, marked by extensive enlargement of the draining lymph nodes, ensues when donor T cells are administered via the footpad. Here, we demonstrate that cells derived from the enlarged draining lymph nodes of A/B F1 animals undergoing local GvH disease caused by donor A T cells contain a subpopulation of host-derived killer T-cell precursors which can be activated to lyse specific blast cells, derived from mixed lymphocyte culture (MLC), reactive to host MHCb alloantigens. These 'anti-idiotypic' cytolytic T cells lyse A anti-MHCb MLC blasts, and also, they lyse anti-MHCb MLC blasts from MHC different, third party rat strains.

Animals↗
PubMedDate not supplied

Paclitaxel formulation as a cause of ethanol intoxication.

OBJECTIVE: To report a case of ethyl alcohol intoxication associated with paclitaxel administration. CASE SUMMARY: A patient who received a 3-hour paclitaxel infusion for metastatic breast carcinoma and developed symptoms of acute alcohol intoxication. A blood ethanol concentration drawn at the end of the paclitaxel infusion was 97.8 mg/dL (0.098%). DISCUSSION: The amount of alcohol contained in paclitaxel is discussed. A review of the literature revealed one patient series where the highest blood alcohol concentration was one-third that seen in our patient. CONCLUSIONS: Clinicians should recognize the potential for alcohol intoxication with paclitaxel administration. This is especially pertinent when higher doses are given over a short period of time.

Antineoplastic Agents, Phytogenic↗