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Biomedical subjects

K Thompson

Publications and source records attributed to K Thompson.

249 records · Page 14Linked to original sources
PubMedDate not supplied

Mechanistic aspects of chiral discrimination on an amylose tris(3,5-dimethylphenyl)carbamate.

The separation of [2R-[2alpha(R*),3alpha]]-5-[[2-[1-[3,5-bis-(trifluoromethyl)phenyl]ethoxy]-3(S)-4-fluorophenyl)4-morpholinyl]-methyl]-N,N-dimethyl-1H-1,2,3-triazole-4-methanamine hydrochloride from its enantiomer was achieved on an amylose tris-3,5-dimethylphenyl carbamate stationary phase. The retention of the enantiomers is dominated by weak hydrogen bonds while the enantioselectivity is governed by other kinds of interactions, e.g., inclusion in the amylose carbamate chains. Van't Hoffplots of 1nalpha vs. reciprocal temperature were non-linear and could be divided into two linear regions. One region at low temperature (5 degrees C- approximately 20 degrees C) and another one between 25 degrees C-70 degrees C with the change in slope occurring between 16 degrees C and 20 degrees C. DSC experiments suggested that the behavior can be attributed to breakage of H-bonds triggering a conformational change. Molecular simulation indicated a correlation between the interaction energies and the elution order obtained experimentally. The most retained enantiomer (R,R,S-enantiomer) interacts with the stationary phase through a hydrogen bond between the triazole proton and the C=O groups of the stationary phase, as well as through an inclusion in the cleft of the stationary phase. The other enantiomer exhibits a bifurcated H-bond between the triazolic proton and the C=O groups of the stationary phase leading to a less stable complex.

Journal Article↗
PubMedDate not supplied

Nutrition during and after cancer treatment: a guide for informed choices by cancer survivors.

Many studies have been conducted about dietary interventions aimed at preventing cancer. The American Cancer Society has published guidelines on diet, nutrition and cancer prevention, which are updated periodically as new evidence emerges, and other groups, too, have issued statements or guidelines about nutritional strategies to prevent cancer. Much less is known, however, about optimal nutrition for cancer survivors. This report looks at the different phases of cancer survivorship, from active treatment to advanced disease, and presents existing evidence from which informed decisions can be made regarding dietary choices. Popular complementary and alternative methods related to dietary intervention are reviewed. Nutrition information is also provided according to common cancer sites. As this is an area that requires survivors and health care providers to communicate effectively, a special section on "frequently asked questions" is provided for use as a patient education handout.

Body Weight↗
PubMedDate not supplied

Combinations of P-glycoprotein blockers, verapamil, PSC833, and cremophor act differently on the multidrug resistance associated protein (MRP) and on P-glycoprotein (Pgp).

Clinical studies are currently in progress to evaluate functional modifiers of P-glycoprotein (Pgp), an efflux pump associated with resistance to cancer chemotherapy. However, the effects of these modifiers on a more recently discovered efflux pump, the multidrug resistance associated protein (MRP), have not yet been fully characterized. MRP is expressed in most human tissues and is overexpressed in several tumor types. For these reasons, we have investigated the effects of three prototype Pgp modifiers, which act by different modes on the function of Pgp, on the function of MRP in two MRP-overexpressing cell lines: UMCC/VP lung and MCF-7/VP breast cancer cells. Clinically optimal plasma levels of verapamil, cremophor, and PSC833 have been shown to completely block the function of Pgp in Pgp-over expressing cells. However, in the two MRP-over expressing cell lines, these modifiers only partially blocked the function of MRP and combinations of these optimal concentrations acted antagonistically. Similar antagonistic effects were seen with combinations of suboptimal concentration levels of these blockers, while these combinations resulted in synergistic effects in Pgp overexpressing cells. For two biophysical parameters measured at the plasma membrane, membrane fluidity and membrane potential, the effects of these modifiers were essentially similar in Pgp and MRP expressing cells. We suggest that the 170 kD Pgp and the 190 kD MRP glycoproteins, imbedded in the plasma membranes, respond differently to simultaneous effects of the investigated prototype resistance modifiers. These results also suggest that the identification of the specific mechanism of drug resistance is important for the selection of chemotherapeutic strategies to block the efflux pump on the cancer cell.

3T3 Cells↗
PubMedDate not supplied

Birth outcomes, health problems, and neglect with prenatal exposure to cocaine.

Thirty children exposed prenatally to maternal use of cocaine were compared to 30 nonexposed subjects on maternal variables, birth outcomes, health problems in early childhood, and issues related to child maltreatment. Cocaine-exposed infants were more likely to have mothers who received inadequate prenatal care, have adverse birth outcomes including prematurity and retarded intrauterine growth, and have health problems beyond the newborn period including small stature and hypertonia. More cocaine-exposed children were placed in foster homes due to maternal neglect.

Adult↗
PubMedDate not supplied

Probing of the rheumatoid factor (RF) V gene repertoire in rheumatoid arthritis (RA) by hybridoma clones.

Twenty human monoclonal antibodies with rheumatoid factor (RF) specificity were produced from fusions using B lymphocytes derived from the synovial tissue of two patients with rheumatoid arthritis (RA) and one with the polyarticular form of juvenile rheumatoid arthritis (JRA) (1). All the 20 monoclonal antibodies were IgM. Fourteen of these were classical RFs with specificity restricted to IgG, and included 12 kappa and 2 lambda proteins. When the fine specificity for IgG Fc determinants were investigated most of them showed the Ga specificity. In addition, 5 lambda and 1 kappa monoclonal RF antibodies showed polyreactivity and also reacted with various other antigens than IgG (1). The 14 monoreactive RFs were further studied for the expression of RF-related cross-reactive idiotypes (CRI) and variable heavy (VH) and light chain (VL) subgroups. Only four of the twelve kappa RFs expressed the V kappa III subgroup. Three of them belong to the V kappa IIIb sub-subgroup and expressed the CRI 17.109. One of these 3 clones in addition expressed the VH I associated CRI G6. Five other monoreactive RFs expressed either or both of the VH III associated CRI B6 and D12 (2). Using staphylococcal protein A (SPA) binding as well as Northern blotting techniques (2), studies indicated that 10 out of the 12 RFs studied expressed the VH III regions and 2 expressed the VH I region. These data, both for the heavy and light chains, indicated a different V gene usage by the RF derived from RA patients than by the RF M-components derived from patients with mixed cryoglobulinemia and Waldenström's macroglobulinemia but without RA.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMedDate not supplied

Lid surgery to reduce discomfort produces an unexpected improvement in visual acuity--a case presentation.

A significant cause of blindness in leprosy is corneal scarring secondary to corneal anaesthesia and lagophthalmos (Brand & ffytche 1985). Such patients may continue to experience considerable ocular discomfort, particularly when there is associated ectropion of the lower lid, with inflammation of the exposed tarsal conjunctiva (Courtright & Johnson 1991). Where visual outcome is no longer the primary consideration, one may hesitate to subject patients to surgery, particularly in relatively unsophisticated field conditions, attempting instead to relieve the patient's discomfort by conservative treatment such as frequent topical ocular lubricants, use of protective spectacles or eye shades etc. A case is presented here in which minor surgery aimed solely at relieving ocular discomfort resulted in an unexpected improvement in visual acuity. This suggests that there are instances where a more aggressive approach to treatment of even severely damaged eyes could prove more rewarding than anticipated.

Eyelid Diseases↗