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R T Cook

Publications and source records attributed to R T Cook.

At least 19 recordsLinked to original sources
PubMed1995

Modulation of T-cell adhesion markers, and the CD45R and CD57 antigens in human alcoholics.

Direct and indirect evidence indicates that T cells are altered in alcoholics. The most commonly reported changes under direct examination have been consistent with an increased level of activation as reflected by shifts in the ratio of common leukocyte antigen isoforms expressed at the cell surface, by increases in the expression of class II antigen, or by alterations in the expression of various adhesion molecules. Functional evidence for T-cell abnormality includes loss of delayed hypersensitivity and a number of findings attributed to dysregulation of B cells by alcoholic T cells; these include the widely reported distrubances of immunoglobulin production in vivo and a range of abnormal responses when T and B cells are combined in vitro. Detailed flow cytometric examination of T cells from alcoholics with or without active liver disease reveals a significant loss of L-selectin CD8+ T cells, but not usually of CD4+ T cells. There is an inverse increase in the expression of CD11b on the CD8+ cells that have decreased L-selectin+ percentages. Both CD8+ and CD4+ T cells in alcoholics display a significant loss of the CD45RA isoform and a gain of cells exhibiting the CD45RO isoform. Other surface alterations include increased expression of CD57, a marker most commonly associated on T cells with conditions of chronic increased antigenic exposure. It is argued that these and other T-cell alterations in alcoholics are cytokine-driven in part and result in T-cell differentiation states that are functionally inappropriate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

The Institute of Medicine report on emergency medical services for children: thoughts for emergency medical technicians, paramedics, and emergency physicians.

The emergency medical technician, the paramedic, and the emergency physician, as well as emergency physicians who have additional expertise in emergency medical service (EMS) prehospital care or pediatric emergency medicine (through experience or formal fellowship training), will all find the Institute of Medicine's report, Emergency Medical Services for Children (EMS-C), to be an invaluable background resource as well as a guide for EMS system and EMS-C-related planning. With both breadth and depth, it reviews many of the issues in EMS-C today from many perspectives and provides practical information to enable these care givers to understand better the "big picture" of EMS-C as well as to assist them in continuing to make a difference in the day-to-day emergency care for children. It is well referenced, engenders respect for all members of the team within the broad continuum of EMS-C, and provides encouragement to them to work together to identify and address issues and solve problems to improve the quality of care for our nation's children.

Allied Health Personnel↗
PubMed1994

Fine T-cell subsets in alcoholics as determined by the expression of L-selectin, leukocyte common antigen, and beta-integrin.

Alcoholics admitted to the hospital solely for detoxication have been studied by flow cytometry to evaluate changes in the surface markers of peripheral blood leukocytes. As we have shown previously, such patients have an elevated percentage of CD8hi lymphocytes that are HLA DR+; we now demonstrate that they also have striking alterations in the quantitative relationships of the fine T-cell subsets. Both CD4+ and CD8hi lymphocytes have a sharply reduced percentage of the L-selectin+ CD45RA+ subset, increased percentages of the CD45RA- subsets, and several other fine subset alterations. The fine subset profile suggests, according to current correlations of phenotype and function, that both CD4+ suppressor inducer and CD4-dependent CD8+ suppressor effector cells are reduced, whereas other subsets, including CD8+ CTL or their precursors, are increased in relative percentages. Some of the phenotypic changes are reversible over the several days following withdrawal. In other results, the percentage of CD8hi lymphocytes epxressing CD11b (beta-integrin) is shown to be reciprocal with the percentage expressing L-selectin both in normals and alcoholics. However, the regression function of CD11b vs. L-selectin on CD8hi cells is different for the alcoholics than for the normals, indicating an abnormality in the regulation of the expression of these two adhesion markers. Taken together, this abnormality of adhesion molecules and the fine subset alterations previously described indicate widespread changes in the peripheral lymphocytes of currently drinking alcoholics. These changes suggest functional deficiencies that may include alterations of lymphocyte traffic and other adhesion-dependent functions, and a shift in the balance of regulatory interactions.

Adult↗
PubMed1991

Activated CD-8 cells and HLA DR expression in alcoholics without overt liver disease.

Lymphocytes from alcoholics without liver disease were immunophenotyped by flow cytometry immediately after admission for detoxication and again after 4 to 10 days of abstinence. We found a small but significant elevation of T lymphocytes at admission compared to controls and decreases in the numbers of B cells and natural killer cells in many patients. A significant elevation of activated T cells was confirmed. The ratio of activated T cells to activated non-T cells was also substantially increased, but declined slightly during early withdrawal. The increase in activated T cells was due mostly to increased numbers of activated CD8hi cells. These activation changes did not revert toward normal as quickly as the other changes and may represent an indication of immune damage at a preclinical stage. An additional finding of interest was a substantial decrease in the expression of HLA DR on CD4+ and non-T cells. The significance of this decrease is not known, but we speculate that it may result in a decline in the efficiency of antigen presentation.

Adult↗
PubMed1991

Is the anteroposterior cervical spine radiograph necessary in initial trauma screening?

The usefulness of the anteroposterior (AP) radiograph of the cervical spine in contributing to the diagnosis of cervical spine injuries in the acute trauma patient was examined in a retrospective study. All cases of cervical spine fracture or dislocation seen at a level I trauma center over a 3-year period and at a rehabilitation center over a 10-year period were reviewed. The lateral radiograph, open-mouth odontoid radiograph, and AP radiograph of each case were sequentially examined by a neuroradiologist (blinded to the original diagnosis) to determine the contribution of each view in making a diagnosis of cervical spine injury. Results of these reviews showed that there were no cases of cervical spine injury evident on the AP view without an obvious corresponding abnormality on the lateral or open-mouth view. It was concluded that the AP view could be dropped from the initial screening radiographic study of the cervical spine in the trauma patient. Only an adequate lateral view and open-mouth odontoid view would then be necessary to initially evaluate the cervical spine in the trauma patient, and decisions to obtain further studies could be based safely on only the lateral and open-mouth views.

Adolescent↗
PubMed1991

Ethanol-induced growth inhibition of erythroleukemia stem cells. Cell cycle effects.

Friend erythroleukemia stem cells are strongly growth inhibited by 60 mM ethanol. The expression of this inhibition requires several days to develop fully, and is not relieved by washing into new ethanol-containing medium even in the presence of excess folic acid. Removal of the fully inhibited cells from ethanol results in rapid growth recovery, with the onset of recovery occurring within a few hours. Cell cycle analysis reveals a G1 delay which is evident within a few hours after initial ethanol exposure. Bivariate RNA-DNA analysis indicates that this G1 delay results from restriction in late G1. It is unclear at present whether this delay can account for all the observed growth inhibition.

Cell Cycle↗
PubMed1990

Ethanol causes accelerated G1 arrest in differentiating HL-60 cells.

The effects of clinically relevant ethanol concentrations on myeloid differentiation in the HL-60 cell promyelocytic leukemia line have been studied. The exposure of noninduced stem cells to 60 mM ethanol results in an increase in G1 cells, but there is no increase in superoxide production or expression of the Mo1 antigen. When HL-60 cells are induced to differentiate along the myeloid line with dimethylsulfoxide (DMSO) or retinoic acid (RA), there is a shift to smaller cell size, an increase in G1 cells and acquisition of the ability to produce superoxide as reported previously by several authors. When ethanol is present during differentiation, there are further increases in G1 cells, and increases in the percentage of cells which produce superoxide and express Mo1, and decreases in mean cell size and total growth during the incubation period. Regrowth experiments after periods of differentiation indicate that the increased G1 arrest seen in the presence of ethanol represents terminal commitment if inducer is present, but in the absence of inducer the increased G1 percentage is readily reversible. Examination of RNA content by flow cytometry reveals a decrease in both the peak and mean G1 RNA content during DMSO or RA induced differentiation. These decreases are accentuated by the presence of ethanol, resulting in a higher G1A/G1B ratio than in nonexposed cells. These findings indicate that ethanol enhances G1 growth arrest in HL-60 cells exposed to myeloid inducers. Partial differentiation occurs during this process, resulting in terminally arrested cells, some of which have undergone fewer postinduction cell divisions than normal and may not be fully competent.

Cell Differentiation↗
PubMed1990

Ethanol induced growth inhibition and growth adaptation in vitro. Cell cycle delay in late G1.

We have characterized the growth responses of HTC rat hepatoma sublines after exposure to clinically relevant concentrations of ethanol. These experiments demonstrate growth inhibition by ethanol, and both adaptive and non-adaptive growth responses after chronic exposure. Examination of the cell cycle compartmentation of HTC lines shows that a rapid accumulation of G0/G1 cells is induced by ethanol. Estimates of cellular G1 RNA content by flow cytometry reveal increases in mean G1 RNA and in late G1 cells in the line which growth adapts, and decreases in these parameters in a line which does not adapt to ethanol. Both the growth responses and the timing of cell cycle restriction by ethanol in the adapting line suggest parallels with the reported data for regenerating rat liver. Ethanol induced late G1 restriction appears to be of significant interest in the study of cellular mechanisms which are disturbed by ethanol in proliferating tissues.

Animals↗
PubMed1987

Recognition of a site of a Kentucky bluegrass pollen allergen by antibodies in the sera of allergic and non-atopic humans and a murine monoclonal antibody.

Allergen 27 was isolated from the aqueous extract of Kentucky Bluegrass pollen (KBG-R) with a reversed immunosorbent prepared by coupling murine monoclonal antibody, Mab 27, to Sepharose 4B. Sera of patients allergic to KBG pollen, as well as serum of nonatopic individuals possessing anti-KBG antibodies, inhibited the binding of Mab 27 to either Ag 27 or KBG-R to the extent of 20 to 35% in ELISA. In contrast, sera devoid of antibodies to KBG-R had no inhibitory capacity. In a radioallergosorbent test, it was demonstrated that Mab 27 could inhibit the binding of human IgE antibodies to Ag 27 to the extent of 52%. From these results, it is concluded that Ag 27 contains a determinant recognized by both human IgE and blocking antibodies and a murine Mab.

Allergens↗
PubMed1987

Pneumocystis carinii. Taxonomy as viewed by electron microscopy.

Pneumocystis carinii is an opportunistic unicellular organism that can cause serious pulmonary infection in immunosuppressed patients. The taxonomy and classification of P. carinii has not yet been settled. The authors present transmission and scanning electron microscopic (TEM and SEM) observations of tissue from two patients with pulmonary Pneumocystis infections. The infectious organisms display marked variability in shape and size. They appear to divide by binary fission and lack motility organelles, Golgi apparatus, phagosomes, and lysosomes. The mitochondria and endoplasmic reticulum were poorly developed. The nucleus was rather ill defined, and there appeared to be asynchrony in the development of nuclear membranes and cytoplasm. The authors contend that there are firm ultrastructural evidences against the claim for a protozoan nature of Pneumocystis and in favor of its being a fungus, albeit of a primitive form, in which the mycelium is reduced to a unicellular state but the ability to sporulate is preserved.

Cell Nucleus↗
PubMed1986

Proliferative responses by immune murine popliteal lymph node cells to high-molecular-weight basic allergen of ryegrass pollen and its cyanogen bromide fragments.

High-molecular-weight basic allergen (HMBA) of ryegrass pollen and its fragmented form obtained by cleavage with cyanogen bromide (CNBr) (HMBA-frag) were evaluated for their immunogenicity in terms of their capacity to stimulate the in vitro proliferative responses of the in vivo antigen-primed popliteal lymph node (PLN) cells. For this purpose, mice (C3H/HeJ) were immunized in the hind foot pads with solutions containing 1-5 micrograms of HMBA or HMBA-frag emulsified in Freund's complete adjuvant (FCA). Eleven days later, single-cell suspensions of the PLN were cultured in vitro for 4 days in the presence of either HMBA or HMBA-frag at concentrations ranging from 0.625 to 20 micrograms/ml. 3H-thymidine was added to the cultures 6 h prior to harvesting the cells. The degree of proliferation was assessed from the extent of intracellular incorporation of the 3H-thymidine by the PLN cells. Comparable degrees of lymphocyte proliferation were consistently obtained on stimulation with either HMBA or HMBA-frag of PLN cells from mice immunized with the allergen HMBA. A similar finding was made using PLN cells from mice immunized with the HMBA-frag. This study demonstrated that the CNBr-derived fragments of HMBA retained the immunogenicity of the parent molecule HMBA in terms of being able to (i) induce the in vivo priming of PLN cells and (ii) elicit the in vitro proliferative response of the antigen-primed PLN cells.

Allergens↗