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T McIntyre

Publications and source records attributed to T McIntyre.

14 recordsLinked to original sources
PubMed2000

Analysis of oxidized glycerophosphocholine lipids using electrospray ionization mass spectrometry and microderivatization techniques.

Oxidized low-density lipoprotein (LDL) is thought to play an important role in atherogenesis and cardiovascular disease in humans. Oxidized LDL is a complex mixture of many oxidized species, including numerous oxidized glycerophospholipids. Electrospray ionization and tandem mass spectrometry as well as microchemical derivatization of high-performance liquid chromatographically purified fractions derived from oxidized LDL were investigated as means to determine the structure of individual components present in oxidized LDL. One major oxidized phosphocholine lipid had an [M + H](+) ion at m/z 650. Derivatization to the trimethylsilyl ether and methoxime caused shifts in mass which, along with negative ion collision-induced dissociation mass spectra, were consistent with the presence of three species, 1-palmitoyl-2-(9-oxononanoyl)glycerophosphocholine and two isomeric 1-octadecanoyl-2-(hydroxyheptenoyl)glycerophosphocholines. These species were chemically synthesized. Trimethylsilylation of free hydroxyl groups increased the mass of the phospholipid acyl chains containing hydroxyl groups by 72 u. Conversion of carbonyl groups to the methoxylamine derivative increased the mass by 29 u. Ozonolysis of those products which contained double bonds proved to be a facile technique to determine the position and number of double bonds present. The use of these techniques was illustrated in the structural characterization of one major component (m/z 650, positive ions) in oxidized LDL as 1-octadecanoyl-2-(7-hydroxyhepta-5-enoyl)glycerophosphocholi ne. A possible mechanism for the formation of this unique chain-shortened glycerophospholipid is proposed.

Chromatography, High Pressure Liquid↗
PubMed1993

Clinical use of androgenic steroids at a major medical center: who prescribes androgens and how well do they do it?

To assess prescribing practices for androgens at Wilford Hall USAF Medical Center, the authors analyzed prescriptions for all patients receiving therapy during a 12-month period (n = 201) and reviewed the available outpatient records not maintained elsewhere (n = 105). The most commonly prescribed androgens were testosterone enanthate (144/201; 56.7%), and danazol (52/201; 25.9%). Review of the available outpatient medical records of 73 male patients using testosterone enanthate showed a mean age of 59.5 years, mean frequency of injection of 20 days, mean duration of therapy of 3.5 years, and mean dose of 226 mg. Therapy was initiated by a urologist (34/73; 46.6%), an endocrinologist (33/73; 45.2%), or an internist (6.73; 8.2%). Indications for therapy based on pretreatment laboratory and historical data included hypergonadotropic hypogonadism (24/73; 32.9%), hypogonadotropic hypogonadism (23/73; 31.5%), unspecified hypogonadism (7/73; 9.6%), and empiric treatment of elderly men with erectile dysfunction without evidence of hypogonadism (9/73; 26%). Pretreatment prostate examinations as well as measurement of serum testosterone (66/73; 90.4%) and serum gonadotropins (52/73; 71.2%) were often not performed. The authors conclude that records of patients treated with androgens show: 1) Doses are appropriate; 2) Empiric treatment of erectile dysfunction in elderly men is common despite the associated risks; 3) Laboratory and physical evaluation before treatment is often incomplete; 4) There was no evidence of androgenic substance abuse in patients studied.

Adolescent↗
PubMed1993

Immunocompetence in the long sleep and short sleep mouse lines: baseline versus primed responses.

Two lines of mice which were selectively bred for high (Long Sleep; LS) and low (Short Sleep; SS) reactivities to a sedative dose of ethanol, are also differentiated by agents that act at the GABAA-receptor complex. Since this supramolecular complex may also modulate immune function, measures of immunity have been examined in these lines. In the present study the immune responsiveness before and after an allogeneic priming stimulus was investigated. Lower mitogen-induced T-cell proliferation, mixed leukocyte reaction, and cytotoxic T lymphocyte activity were found in unprimed LS compared to unprimed SS mice. In contrast, the LS line exhibited a marked augmentation of these responses after priming, while the SS mice appeared unresponsive to this challenge. Addition of splenocytes or cell-free splenic cultures from primed mice to cultures from unprimed mice suggested that differences in priming-induced cell-to-cell interactions, rather than the release of a soluble helper factor(s) into the medium, are responsible for the marked augmentation of the secondary response in LS, compared to SS mice. Fewer T-helper and T-suppressor/cytotoxic cells were found in LS compared to SS mice, and this was unaffected by priming. These results extend previous findings demonstrating a higher natural killer cell activity and rate of tumor rejection in LS mice and suggest that these lines may be useful in studying the regulatory role of the GABAA complex in immune function.

Animals↗
PubMed1993

Stimulus (instructional) fading during extinction of self-injurious escape behavior.

Three individuals with developmental disabilities were exposed to a series of assessment conditions to identify the source of reinforcement for their self-injurious behavior. In each case, self-injury occurred most often in instructional (demand) situations containing a brief time-out from the task contingent on self-injury, indicating that the behavior was an escape response (i.e., maintained by negative reinforcement). Treatment was implemented in a multiple baseline across subjects design and consisted of extinction (prevention of escape) plus instructional fading (initial elimination of instructions followed by their gradual reintroduction). Results showed that the combined treatment produced immediate and large reductions in self-injury that were maintained as the frequency of instructions was increased across sessions to match the original baseline rate of presentation. Results of a component analysis conducted with 1 subject suggested that stimulus fading accelerated the behavior-reducing effects of extinction.

Adolescent↗
PubMed1992

Ethanol inhibits mitogen-induced calcium mobilization in mouse splenocytes.

Ethanol inhibited the mitogen-induced initial increase in cytoplasmic free-calcium [Ca2+]i in mouse splenocytes. This effect was concentration-dependent, reversible, and observed at pharmacologically relevant concentrations (24-166mM). Other short-chain alcohols such as propanol, butanol, and pentanol also inhibited this mitogen-induced increase in [Ca2+]i. The potencies of these alcohols to produce this effect were highly correlated (r = 0.98, p less than 0.001) with their membrane/buffer partition coefficients. Analysis of mouse splenocyte subpopulations demonstrated that this effect was manifest in both B and T lymphocytes. Within T lymphocyte subpopulations, both CD4+ and CD8+ T cells were affected. These results suggest that the inhibition of [Ca2+]i increase may be an early event mediating ethanol-induced immunosuppression and that this may be a predisposing factor to infection and malignancies associated with alcoholism.

Alcoholism↗
PubMed1991

Morphine-induced thymic hypoplasia is glucocorticoid-dependent.

Mice administered morphine as a s.c. pellet implant exhibit a marked and sustained thymic hypoplasia as well as suppression of T lymphocyte functions. In the present study, the effects of morphine on thymocyte differentiation were characterized. Morphine produced a significant decrease in both the number and proportion of CD4+/CD8+ double positive (DP) cells. The percentage of the CD4+/CD8-, CD4-/CD8+, and CD4-/CD8- double negative subsets in these mice was proportionally increased. Morphine also increased the proportion of cells expressing either the epsilon-chain of the CD3 complex or the IL-2R. The initial reduction in the proportion of DP thymocytes appeared fully recovered by 10 days post-implantation, although the number of DP thymocytes gradually returned to normal over a 3-wk period. Morphine administration resulted in a marked increase in serum corticosterone levels, and a single injection of dexamethasone mimicked the effects of morphine on thymus differentiation. Furthermore, adrenalectomy abolished the morphine-induced decrease in CD4+/CD8+ thymocytes relative to a sham-operated group. The present findings are consistent with the hypothesis that morphine-induced thymic hypoplasia may be mediated by an increase in the circulating levels of corticosterone.

Adrenalectomy↗
PubMed1991

Stress modulates calcium mobilization in immune cells.

Both acute and chronic restraint stress modulated mitogen-induced increases in cytoplasmic free-calcium concentrations ([Ca2+]i) in mouse spleen cells. Dual-color analysis of lymphocyte subpopulations demonstrated that acute (2 hour) restraint stress suppressed mitogen-stimulated increases in [Ca2+]i in CD4+ T cells, but enhanced [Ca2+]i in CD8+ T cells. Chronic restraint stress (2 hours daily for up to 21 days) resulted in a significant suppression of mitogen-stimulated increases in [Ca2+]i in CD4+ T cells at 3 and 7 days, but not at 21 days. CD8+ T cells were unaffected by chronic stress. Chronic stress (for 7 days) had a modest suppressive effect on mitogen-induced Ca2+ responses in B cells. Within T lymphocyte subpopulations, both acute and chronic stress predominantly affected CD4+ T cells, which may induce a functional reversal of the CD4/CD8 ratios in vivo. Such a reversal could result in suppression of a variety of immune responses such as lymphocyte proliferation and antigen-specific antibody production. These findings indicate that the inhibitory effects of stress on calcium mobilization in lymphocytes may be an early event mediating stress-induced immunosuppression.

Acute Disease↗
PubMed1991

Inhibition of calcium mobilization is an early event in opiate-induced immunosuppression.

Morphine administered as a subcutaneous implant inhibits the initial increase in cytoplasmic free-calcium [Ca2+]i induced by mitogens in mouse splenocytes. This effect was not reproduced by incubation of splenocytes with morphine (10(-8)-10(-4) M). Analysis of splenocyte subpopulations demonstrates that this effect was manifest in both B and T cells. However, within T cell subpopulations, CD4+ but not CD8+ cells were affected. Adrenalectomy abolished this effect of morphine in CD4+ T but not CD4-, CD8- spleen cells (most likely Thy 1.2- B cells). Moreover, simultaneous administration of the opiate antagonist naltrexone blocked the effect of morphine in CD4-, CD8- spleen cells, but not in CD4+ T cells. These data indicate that the effects of morphine on mitogen-stimulated increase in [Ca2+]i may be mediated through distinct glucocorticoid-dependent and -independent mechanisms. The morphine-induced inhibition of an increase in [Ca2+]i in immune cells reported here may be an early event mediating opiate-induced immunosuppression.

Animals↗
PubMed1991

t-[35S]butylbicyclophosphorothionate binding under equilibrium and nonequilibrium conditions: differential effects of barbiturates and gamma-aminobutyric acid in the long-sleep and short-sleep selected mouse lines.

Significant differences were demonstrated between the long-sleep (LS) and short-sleep (SS) selected mouse lines in the abilities of barbiturates and gamma-aminobutyric acid (GABA) to inhibit t-[35S]butylbicyclophosphorothionate [( 35S]TBPS) binding to well-washed cerebral cortical membranes. Thus, using phenobarbital to initiate the dissociation of [35S]TBPS, the extent of inhibition was significantly greater in LS mice (but not SS mice) than would be predicted using equilibrium conditions. Pentobarbital had the opposite effect, causing [35S]TBPS to dissociate to a greater extent in SS than LS membranes. [35S]TBPS binding was dissociated from LS and SS membranes by GABA to a greater and lesser extent, respectively, than would be predicted from equilibrium studies. Because no line differences in the potencies of these drugs to inhibit [35S]TBPS binding were found using equilibrium conditions, these results indicate that the association rates of barbiturates and GABA may be different between these lines. These findings are consistent with neurochemical studies indicating differences in the benzodiazepine/GABA receptor-chloride channel complex in these selected lines and may explain their differential sensitivities to certain agents acting through this supramolecular complex.

Animals↗
PubMed1991

Effects of various music conditions on multiple dimensions of behavior of emotionally disturbed adolescents.

The effects of music on the behaviors of 5 to 8 emotionally disturbed adolescents were investigated. Six behavioral categories of aggressive motor, aggressive verbal, disruptive motor, disruptive verbal, nondisruptive/off task, and on task, were monitored in class daily for 40 min. for 12 wk. to assess whether three conditions of "sedative," "stimulating," and "no music" influenced the frequency of these behaviors. Analysis indicated no significant differences in frequencies of any of the six behavior categories among music conditions.

Adolescent↗