Body temperature patterns during natural fevers in a herd of free-ranging impala (Aepyceros melampus).
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Biomedical subjects
Publications and source records attributed to D Mitchell.
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The biological functions of the tumor suppressor, ING1, have been studied extensively in the last 5 years since it was cloned. It shares many biological functions with those of p53 and has been reported to mediate growth arrest, senescence, apoptosis, anchorage-dependent growth, and chemosensitivity. Some of these functions, such as cell cycle arrest and apoptosis, have been shown to be dependent on the activity of both ING1 and p53 proteins. In this study, we report that p33(ING1) (one of ING1 isoforms) is also involved in the modulation of DNA repair. We found that overexpression of p33(ING1) enhances repair of UV-damaged DNA and that p53 is required for the repair process. Furthermore, binding between ING1 and GADD45 has been detected. These observations suggest that p33(ING1) cooperates with p53 in nucleotide excision repair and that GADD45 may be one of its components.
Body temperature has a circadian rhythm, and in women with ovulatory cycles, also a menstrual rhythm. Body temperature and sleep are believed to be closely coupled, but the influence on their relationship of gender, menstrual cycle phase and female reproductive hormones is unresolved. We investigated sleep and 24 h rectal temperatures in eight women with normal menstrual cycles in their mid-follicular and mid-luteal phases, and in eight young women taking a steady dose of oral progestin and ethinyl oestradiol (hormonal contraceptive), and compared their sleep and body temperatures with that of eight young men, sleeping in identical conditions. All subjects maintained their habitual daytime schedules. Rectal temperatures were elevated throughout 24 h in the luteal phase compared with the follicular phase in the naturally cycling women, consistent with a raised thermoregulatory set-point. Rectal temperatures in the women taking hormonal contraceptives were similar to those of the naturally cycling women in the luteal phase. Gender influenced body temperature: the naturally cycling women and the women taking hormonal contraceptives attained their nocturnal minimum body temperatures earlier than the men, and the naturally cycling women had blunted nocturnal body temperature drops compared with the men. Sleep architecture was essentially unaffected by either menstrual cycle phase or gender. The women taking hormonal contraceptives had less slow wave sleep (SWS), however, than the naturally cycling women. Gender, menstrual cycle phase and hormonal contraceptives significantly influenced body temperature, but had only minor consequences for sleep, in the young men and women in our study.
Female reproductive steroids, oestrogen and progesterone, not only affect reproductive function, but also thermoregulation and sleep. Chronic administration of synthetic steroids, as occurs in women taking oral contraceptives, may affect these regulatory systems differently from endogenous oestrogen and progesterone. We therefore investigated body temperature and sleep in ten young women taking oral contraceptives, in the active and placebo phases of the contraceptive pack, and compared them to a group of nine women with ovulatory cycles, in the mid-follicular and mid-luteal phases. Body temperature was raised throughout 24 h in the women taking oral contraceptives in the active phase, and in the naturally cycling women in the luteal phase, compared to the follicular phase. The women taking oral contraceptives in the placebo phase, however, continued to have raised body temperatures, similar to those in the active phase, indicating a prolonged action of synthetic reproductive steroids on body temperature. Sleep also was influenced by the endogenous and synthetic reproductive steroids, but independently of body temperature. The women taking oral contraceptives had more stage-2 non-rapid eye movement sleep in the active phase, both compared to their placebo phase and the naturally cycling women. The naturally cycling women, however, had more slow wave sleep in the luteal phase compared to the contraceptive group of women. Exogenous reproductive steroids therefore influence body temperature and sleep differently from endogenous progesterone and oestrogen.
EAE can refer either to experimental autoimmune encephalomyelitis or experimental allergic encephalomyelitis. Although EAE is classically a prototypic T helper 1 (TH1) cell-mediated autoimmune disease, it can also be induced by TH2 cells. Characteristically, the most severe manifestation of allergy, anaphylaxis, is associated with exposure to a foreign antigen that is often derived from medication, insect venom or food. We report here that, after self-tolerance to myelin is destroyed, anaphylaxis may be triggered by a self-antigen, in this case a myelin peptide. "Horror autotoxicus", which was initially described by Ehrlich, may not only include autoimmunity to self, it may also encompass immediate hypersensitivity to self, which leads to shock and rapid death.
Milk intake constitutes an important source of dietary calcium for young girls but declines throughout childhood. Recent work shows that the intake of soft drinks may contribute to this decline. Influences on the apparent tradeoff between soft drinks and milk in young girls' diets are not well described. The objective of this research was to test a model depicting maternal beverage choices as predictors of their daughters' milk and soft drink intake. A structural equation model describing maternal influences on daughters' milk, soft drink and calcium intakes was tested using data from 180 non-Hispanic, white families with 5-y-old daughters. Mothers' calcium, milk and soft drink intakes were evaluated as predictors of their daughters' intakes. Mothers' and daughters' soft drink intakes were also examined as predictors of their own milk and calcium intakes. The model provided a good fit to the data, revealing mother-daughter similarities in beverage intake. Mothers who drank milk more frequently had daughters who drank milk more frequently and drank fewer soft drinks. For both mothers and daughters, soft drink consumption was negatively related to both milk and calcium intake. This research provides evidence that mothers' beverage choices influence the tradeoff between milk and soft drinks in their daughters' diets. In particular, mothers' milk and soft drink intakes may affect their daughters' calcium adequacy in early childhood by influencing the frequency with which their daughters consume those beverages.
Maternal and fetal body temperatures were measured in five Boer goats, of mean mass 64 +/- 8 kg, using temperature-sensitive radiotelemeters implanted intra-abdominally. Body temperatures were recorded every 5 min. Throughout the last month of gestation, fetal temperature was approximately 0.6 (o)C higher than that of the mother, in normal laboratory conditions (ambient air temperature: 21-24 (o)C). This feto-maternal temperature difference between the goat fetus and its mother is similar to that found in other mammals, including sheep. When the pregnant goats were subjected to short-term heating and cooling, the difference between maternal and fetal body temperatures changed. Thus the mean difference between fetal and maternal body temperatures decreased from 0.4 to 0.2 (o)C during 2 h of heating, while it widened from 0.3 to 0.7 (o)C during 6 h of cooling. These data support the idea that the fetus is thermally protected from excursions of body temperature during changes in the mother's thermal environment. Reports of goat stock losses and abortions during cold spells in their natural habitats may be the result of more severe and/or prolonged cold exposures that not only adversely affect fetal or maternal body temperature, but also influence other aspects of metabolism. Experimental Physiology (2001) 86.2, 199-204.
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Selective brain cooling (SBC) is defined as a brain temperature cooler than the temperature of arterial blood from the trunk. Surrogate measures of arterial blood temperature have been used in many published studies on SBC. The use of a surrogate for arterial blood temperature has the potential to confound proper identification of SBC. We have measured brain, carotid blood, and rectal temperatures in conscious sheep exposed to 40, 22, and 5 degrees C. Rectal temperature was consistently higher than arterial blood temperature. Brain temperature was consistently cooler than rectal temperature during all exposures. Brain temperature only fell below carotid blood temperature during the final few hours of 40 degrees C exposure and not at all during the 5 degrees C exposure. Consequently, using rectal temperature as a surrogate for arterial blood temperature does not provide a reliable indication of the status of the SBC effector. We also show that rapid suppression of SBC can result if the animals are disturbed.
We examined 8 data sets to determine whether it is possible to attain acceptable levels of internal consistency (coefficient alpha) reliability for the 4 Object Relations and Social Cognition scales (ORSC; Westen, Lohr, Silk, Kerber, & Goodrich, 1989) for the Thematic Apperception Test (TAT; Murray, 1943) when cards are considered as items in a scale. Number of cards used in the data sets ranged from 4 to 10, and the Spearman-Brown prophecy formula was applied to estimate the number of cards that would be required to attain alpha levels of different magnitudes. The two more structural subscales (Complexity of Representations and Understanding of Social Causality) have somewhat higher consistencies than the two more affective ones (Affect Tone and Capacity for Emotional Investment and Moral Standards). The results suggest that the use of 10 to 12 cards provides internal consistencies of alpha > or = .70 across each of the 4 ORSC scales.
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L-selectin has been shown to be important in mediating leukocyte recruitment during inflammatory responses. Although there are numerous in vitro studies demonstrating that engagement of L-selectin leads to the activation of several signaling pathways potentially contributing to subsequent adhesion, emigration, or even migration through the interstitium, whether this actually induces cellular events in vivo is completely unknown. Therefore, we used intravital microscopy to visualize the role of L-selectin in downstream leukocyte adhesion, emigration, and interstitial migration events in wild-type and L-selectin-deficient (L-selectin(-/-)) mice. The cremaster muscle was superfused with the chemotactic inflammatory mediators platelet-activating factor or KC. Leukocyte rolling, adhesion, and emigration in postcapillary venules were examined, and the migration of emigrated leukocytes was recorded continuously using time-lapse videomicroscopy. Platelet-activating factor increased leukocyte adhesion to a similar level in both wild-type and L-selectin(-/-) mice. In contrast, both the number of emigrated leukocytes and the distance of extravascular migration were significantly reduced in L-selectin(-/-) mice. A similar pattern was observed in response to the superfusion of KC. Because superfusion of these mediators induced chemokinesis, we developed a new in vivo chemotaxis assay using slow release of KC from an agarose gel positioned 350 microm from a postcapillary venule. These experiments showed that L-selectin(-/-) leukocytes were also severely impaired in their ability to respond to a directional cue. These findings indicate that L-selectin is important in enabling leukocytes to respond effectively to chemotactic stimuli in inflamed tissues.
The validity of self-reported fruit and vegetable intake in minority populations has not been adequately established. In this study, the authors examined the association of three food frequency questionnaires (FFQs) and 24-hour dietary recalls with serum carotenoid levels. Approximately 1,000 African-American adults recruited from 15 churches in Atlanta, Georgia (1997-1998) completed three fruit and vegetable FFQs: a seven-item instrument assessing intake during the past month; a two-item measure assessing usual intake; and a 36-item measure adapted from the Health Habits and History Questionnaire. A total of 414 participants received a 24-hour recall by telephone, and 105 of them received two additional recalls. Serum levels of lycopene, lutein, cryptoxanthin, alpha-carotene, and beta-carotene were assessed in 813 participants and used as the validity criterion. The correlations of fruit and vegetable servings with specific and total serum carotenoid levels were generally higher for the 36-item FFQ than for the two-item and seven-item instruments. The strongest correlation of fruit and vegetable servings with total carotenoid levels was observed for the three recalls (r = 0.42), with the 36-item FFQ and the single 24-hour recall yielding comparable correlations (r = 0.35 and r = 0.37, respectively). The validity of the 36-item fruit and vegetable FFQ was generally as strong as the validity of both 1 and 3 days of recalls. Given the lower cost and time needed for administration relative to recalls, it appears that the 36-item FFQ has merit for evaluating fruit and vegetable health interventions.
We investigated whether conscious rats exhibit hyperalgesia to noxious mechanical stimuli during tail reperfusion following transient tail ischaemia. Mechanical stimuli were delivered by three mechanical algometers, differing in contact area, geometry and rate of application. Tail ischaemia was induced by applying a pneumatic tourniquet to the base of the tail until the rats exhibited escape behaviour. Control animals had a sham tourniquet placed on their tails. During tail reperfusion, there was significant hyperalgesia when the noxious mechanical stimulus was applied by a narrow bar transverse to the tail, less when applied by a rubber piston, and there was no hyperalgesia when the stimulus was punctate, similar to a von Frey hair. Repeated application of the mechanical stimuli themselves, at 30-min intervals, did not induce hyperalgesia. Rats subjected repetitively to the combination of the bar algometer and tail ischaemia at intervals of at least 48 h, for a total period of three weeks, exhibited progressively enhanced hyperalgesia to the bar algometer, and also enhanced hyperalgesia to noxious ischaemic and thermal stimuli. Rats therefore do exhibit hyperalgesia to mechanical stimuli following conditioning ischaemia, but the nature of the hyperalgesia depends critically on the geometry of the algometer, and the time course of the hyperalgesia was different to that which manifests to a noxious thermal stimulus.
BACKGROUND: The risk factors responsible for an increased prevalence of obesity or overweight in survivors of acute lymphoblastic leukemia (ALL) remain controversial. We evaluated changes in body mass index (BMI) in a cohort of ALL survivors, all of whom have been followed until completion of linear growth. PROCEDURE: BMI (weight/height(2)) was used as an index of adiposity and was calculated at diagnosis, at the end of treatment, and at attainment of final height in a cohort of 126 (59 males) survivors of ALL. BMI was adjusted for age and sex by computing a BMI standard deviation score (SDS) or z score. The spectrum of therapies used included intrathecal chemotherapy given alone (n = 38) or combined with cranial irradiation (CRT; 18 Gy, n = 35; 24 Gy, n = 53) and exposure to prednisone at a low dose (<3.5 gm, n = 49), medium dose (3.5-9.4 gm, n = 46), or high dose (>9.4 gm, n = 30). RESULTS: Overall, mean +/- SEM BMI-SDS increased significantly between diagnosis (-0.18 +/- 0.08) and the end of therapy (0.41 +/- 0.09, P < 0.01), with no significant change thereafter. For patients without CRT, mean BMI-SDS remained unchanged, whereas, for those so treated, mean BMI-SDS increased significantly between diagnosis and the completion of therapy (P < 0.001). The change in mean BMI-SDS was greater in the 24 Gy group vs. the 18 Gy CRT sample (P < 0.005). In a multivariate logistic regression model, CRT was an independent predictor of being overweight (BMI >/=85 percentile) at attainment of final height [odds ratio = 1.6 (95% confidence interval 1.0-23. 1)]. The percentage of subjects who were overweight at attainment of final height was 10.5%, 40%, and 38% for subjects treated with no CRT, 18 Gy CRT, or 24 Gy CRT, respectively (P < 0.01). CONCLUSIONS: Children with ALL given CRT develop increases in their BMI-SDS early on and during treatment and remain at significant risk for becoming overweight as young adults, a development that may increase their already heightened risk for various adverse health outcomes.
OBJECTIVE: To investigate the role of Mycoplasma fermentans in lower respiratory tract disease of HIV-positive patients. METHODS: A polymerase chain reaction (PCR) assay was used to detect M. fermentans in broncho-alveolar lavage (BAL) fluid and peripheral blood mononuclear cells (PBMCs) collected from 78 hospitalized HIV-positive patients with lower respiratory tract disease (the index group). BAL specimens were also assessed from two control groups; 25 HIV-positive patients without respiratory symptoms and 46 patients with a respiratory illness who did not have risk factors for HIV. RESULTS: Seventy-one (91%) of the 78 patients who comprised the index group had AIDS. Sixty-one patients provided BAL and PBMC specimens; 16 provided a BAL specimen and one only a PBMC specimen; 15 (25%) of the 61 patients had M. fermentans positive BAL fluid, of whom 10 (67%) also had a positive PBMC specimen. In contrast, of the 46 patients who had a negative BAL fluid, only three (6.4%) had a positive PBMC sample (P < 0.00001 Fisher's exact test). Overall, 21 (27%) of 77 patients had M. fermentans positive BAL fluid. Of these positive patients, 16 also had another microorganism in the BAL fluid and for five patients M. fermentans was detected alone. Compared with patients in the index group, none of the 46 BAL fluid specimens from patients at low risk of HIV infection was M. fermentans positive (P < 0.001, chi2 15.13). Two (8%) of the 25 HIV-positive patients without respiratory symptoms had a M. fermentans positive BAL fluid, positivity that was also statistically different from the index group (P = 0.045, chi2 4.01). CONCLUSIONS: M. fermentans frequently invades the lower respiratory tract of AIDS patients as an opportunist and may cause disease in some.
BACKGROUND: Eat for Life, a multicomponent intervention to increase fruit and vegetable (F & V) consumption among African Americans, is delivered through African American churches. METHODS: Fourteen churches were randomly assigned to one of three treatment conditions: 1) comparison; 2) culturally-sensitive multicomponent intervention with one phone call; and 3) culturally-sensitive multicomponent intervention with four phone calls. The intervention included an 18-minute video, a project cookbook, printed health education materials, and several "cues" imprinted with the project logo and a 5 A Day message. A key element of the telephone intervention was the use of motivational interviewing, a counseling technique originally developed for addictive behaviors. Major outcomes for the trial included total F & V intake, assessed by food-frequency questionnaires (FFQs) and 24-hour recalls, and serum carotenoids. Psychosocial variables assessed included outcome expectations, barriers to F & V intake, preference for meat meals, neophobia, social support to eat more F & V, self-efficacy to eat more F & V, and nutrition knowledge. RESULTS: Baseline mean F & V intakes across the three FFQs ranged from 3.45 to 4.28 servings per day. Intake based on a single 24-hour recall was 3.0 servings. Variables positively correlated with F & V intake included self-efficacy, outcome expectations, and a belief that F & V contain vitamins. Factors negatively correlated with intake include perceived barriers, meat preference, neophobia, and high-fat cooking practices. The completion rate for the first telephone counseling call was 90%. Completion rates for the remaining three calls ranged from 79% to 86%. CONCLUSION: The recruitment and intervention methods of the Eat for Life study appear promising. The telephone intervention based on motivational interviewing is potentially useful for delivering dietary counseling.