Reflex cardiovascular response to brief abdominal visceral ischemia is mediated in part by prostaglandins.
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Prostaglandin concentrations are elevated in intestinal lymph during brief abdominal visceral ischemia, and exogenously applied prostaglandins can directly stimulate or sensitize ischemically sensitive visceral sympathetic nerve fibers. However, it is not known if prostaglandin production during abdominal ischemia is sufficient to contribute to the reflex cardiovascular response (e.g., hypertension). Accordingly, in anesthetized cats, the femoral artery was cannulated for measurement of arterial blood pressure, and the superior mesenteric and celiac arteries were isolated and fitted with snare occluders. After dual occlusion of these arteries ( 0.05). In group 2, acetylsalicylic acid significantly (P < 0.05) reduced the reflex rise in blood pressure by 46% (28 +/- 3 to 15 +/- 4 mmHg). A second, more invasive preparation (group 3) was utilized to 1) minimize the confounding, transient, nonreflex rise in blood pressure associated with arterial ligation, and 2) further assess the inhibitory effect of indomethacin. In group 3, the ischemia-induced blood pressure rise of 28 +/- 6 mmHg was reduced by 43% to 16 +/- 4 mmHg after indomethacin (n = 4, P < 0.05). Thus blockade of the cyclooxygenase pathway by two structurally dissimilar inhibitors attenuated the visceral-cardiovascular reflex response to brief ischemia, suggesting that prostaglandins released during visceral ischemia contribute significantly to the activation of the reflex cardiovascular response. (+info)
Effects of a physiological GH pulse on interstitial glycerol in abdominal and femoral adipose tissue.
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Physiologically, growth hormone (GH) is secreted in pulses with episodic bursts shortly after the onset of sleep and postprandially. Such pulses increase circulating levels of free fatty acid and glycerol. We tested whether small GH pulses have detectable effects on intercellular glycerol concentrations in adipose tissue, and whether there would be regional differences between femoral and abdominal subcutaneous fat, by employing microdialysis for 6 h after administration of GH (200 microgram) or saline intravenously. Subcutaneous adipose tissue blood flow (ATBF) was measured by the local Xenon washout method. Baseline of interstitial glycerol was higher in adipose tissue than in blood [220 +/- 12 (abdominal) vs. 38 +/- 2 (blood) micromol/l, P < 0.0005; 149 +/- 9 (femoral) vs. 38 +/- 2 (blood) micromol/l, P < 0.0005] and higher in abdominal adipose tissue compared with femoral adipose tissue (P < 0.0005). Administration of GH induced an increase in interstitial glycerol in both abdominal and femoral adipose tissue (ANOVA: abdominal, P = 0. 04; femoral, P = 0.03). There was no overall difference in the response to GH in the two regions during the study period as a whole (ANOVA: P = 0.5), but during peak stimulation of lipolysis abdominal adipose tissue was, in absolute but not in relative terms, stimulated more markedly than femoral adipose tissue (ANOVA: P = 0. 03 from 45 to 225 min). Peak interstitial glycerol values of 253 +/- 37 and 336 +/- 74 micromol/l were seen after 135 and 165 min in femoral and abdominal adipose tissue, respectively. ATBF was not statistically different in the two situations (ANOVA: P = 0.7). In conclusion, we have shown that a physiological pulse of GH increases interstitial glycerol concentrations in both femoral and abdominal adipose tissue, indicating activated lipolysis. The peak glycerol increments after GH were higher in abdominal adipose tissue, perhaps due to a higher basal rate of lipolysis in this region. (+info)
Recurrent inflammation in a site of previous necrotising fasciitis during intravenous CMF chemotherapy.
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We present the case history of a patient with breast carcinoma who developed repeated inflammation at the site of previous necrotising fasciitis following each cycle of intravenous CMF chemotherapy. This complication has not previously been reported. (+info)
The contribution of facilitation of monosynaptic PSPs to dishabituation and sensitization of the Aplysia siphon withdrawal reflex.
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To examine the relationship between synaptic plasticity and learning and memory as directly as possible, we have developed a new simplified preparation for studying the siphon-withdrawal reflex of Aplysia in which it is relatively easy to record synaptic connections between individual identified neurons during simple forms of learning. We estimated that monosynaptic EPSPs from LE siphon sensory neurons to LFS siphon motor neurons mediate approximately one-third of the reflex response measured in this preparation, which corresponds to siphon flaring in the intact animal. To investigate cellular mechanisms contributing to dishabituation and sensitization, we recorded evoked firing of LFS neurons, the siphon withdrawal produced by stimulation of an LFS neuron, the complex PSP in an LFS neuron, and the monosynaptic PSP from an "on-field" or "off-field" LE neuron to an LFS neuron during behavioral training. Unlike the simplified gill-withdrawal preparation (Cohen et al., 1997; Frost et al., 1997), in the siphon-withdrawal preparation we found no qualitative differences between the major cellular mechanisms contributing to dishabituation and sensitization, suggesting that dissociations that have been observed previously may be attributable to transient inhibition that does not occur for this component of the reflex. Furthermore, in the siphon-withdrawal preparation, all of the various cellular measures, including monosynaptic PSPs from either on-field or off-field LE neurons, changed approximately in parallel with changes in the behavior. These results provide the most direct evidence so far available that both dishabituation and sensitization involve multiple mechanisms, including heterosynaptic facilitation of sensory neuron-motor neuron PSPs. (+info)
The role of positron emission tomography (PET) in the management of lymphoma patients.
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BACKGROUND: Treatment of both Hodgkin's disease (HD) and aggressive non-Hodgkin's lymphoma (NHL) with abdominal presentation at the time of diagnosis is often followed by detection of residual masses by computed tomography (CT). However, CT is usually unable to discriminate between residual tumor and fibrosis/necrosis. We investigated the ability of fluorine-18 fluorodeoxyglucose positron emission tomography (PET) to differentiate between residual active tumor tissue and fibrosis. PATIENTS AND METHODS: Forty-four patients with HD or aggressive NHL presenting abdominal involvement (41% with bulky mass) were studied with CT and PET at the end of chemotherapy +/- radiation therapy. RESULTS: After treatment, seven patients had negative PET and CT, and none of them relapsed. The remaining 37 patients all had positive CT (abnormalities < or = 10%). All of the 13 who also had positive PET relapsed (100%). By contrast, there was only 1 (4%) relapse among the 24 patients who were positive at CT but negative at PET. The two-year actuarial relapse-free survival rate was 95% for those with negative PET compared with 0% for positive PET patients (P < 0.000000). CONCLUSIONS: In lymphoma patients with abdominal masses who present CT positivity at restaging, PET should be considered the noninvasive imaging modality of choice for differentiating early recurrences or residual disease from fibrosis. (+info)
Relationship of intra-abdominal adiposity and peripheral fat distribution to lipid metabolism in an island population in western Japan: gender differences and effect of menopause.
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Intra-abdominal adiposity is associated with unfavorable serum lipid profiles (high total cholesterol or triacylglycerol, and low high-density lipoprotein cholesterol) in obese people. However, the relation in mainly nonobese Japanese population is not well known. We examined the relationship between intra-abdominal adiposity measured by ultrasonography and body fat distribution with serum lipids in Japanese people living in an island in western Japan. Mainly nonobese healthy individuals (98 men, 72 premenopausal and 182 postmenopausal women) aged between 33 and 69 years were examined. Accumulation of intra-abdominal fat (Pmax) and abdominal subcutaneous fat (Smin) was measured by ultrasonography. We also measured triceps and subscapular skinfold thicknesses, and the concentrations of total cholesterol, triacylglycerol and high-density lipoprotein (HDL) cholesterol. In men and postmenopausal women, Pmax correlated significantly with the majority of serum lipids after adjusting for age, body mass index and smoking habit. In premenopausal women, Pmax correlated significantly with only total cholesterol, but marginally with triacylglycerol and HDL/total cholesterol ratio after adjustment. Our findings suggest that intra-abdominal adiposity is related to unfavorable lipid profile in both genders among mainly nonobese Japanese population. (+info)
Production of soluble tumor necrosis factor receptors by human subcutaneous adipose tissue in vivo.
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To investigate in vivo adipose tissue production of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and their soluble receptors: TNF receptor type I (sTNFR-I), TNF receptor type II (sTNFR-II), and IL-6 receptor (sIL-6R), we determined arteriovenous differences in their levels across abdominal subcutaneous adipose tissue in obese subjects. Subjects had a median (interquartile range) age of 44.5 (27-51.3) yr, body mass index (BMI) of 32.9 (26. 0-46.6) kg/m(2), and %body fat of 42.5 (28.5-51.2) %. Although there was not a significant difference in the arteriovenous concentrations of TNF-alpha (P = 0.073) or sTNFR-II (P = 0.18), the levels of sTNFR-I (P = 0.002) were higher in the vein compared with artery, suggesting adipose tissue production of this soluble receptor. There was a significant arteriovenous difference in IL-6 (P < 0.001) but not in its soluble receptor (P = 0.18). There was no relationship between TNF-alpha levels and adiposity indexes (r(s) = 0.12-0.22, P = not significant); however, levels of both its soluble receptor isomers correlated significantly with BMI and %body fat (sTNFR-I r(s) = 0.42-0.72, P < 0.001; sTNFR-II r(s) = 0.36-0.65, P < 0.05- <0. 001). IL-6 levels correlated significantly with both BMI and %body fat (r(s) = 0.51, P = 0.004, and r(s) = 0.63, P < 0.001), but sIL-6R did not. In conclusion, 1) soluble TNFR-I is produced by adipose tissue, and concentrations of both soluble isoforms correlate with the degree of adiposity, and 2) IL-6, but not its soluble receptor, is produced by adipose tissue and relates to adiposity. (+info)
Waist circumference, waist:hip ratio, and risk of breast cancer in the Nurses' Health Study.
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This study examined prospectively the associations of waist circumference and waist:hip circumference ratio with risk of breast cancer. A total of 47,382 US registered nurses who reported their waist and hip circumferences in 1986 were followed up through May 1994 for identification of incident cases of breast cancer. During 333,097 person-years of follow-up, 1,037 invasive breast cancers were diagnosed. In proportional hazards analyses, waist circumference was nonsignificantly related to risk of premenopausal breast cancer but was significantly associated with postmenopausal breast cancer after adjustment for established breast cancer risk factors (for the highest quintile of waist circumference vs. the lowest, relative risk (RR) = 1.34; 95% confidence interval (CI): 1.05, 1.72). When the analysis was limited to postmenopausal women who had never received hormone replacement therapy, a stronger positive association was found (RR = 1.88; 95% CI: 1.25, 2.85). After the data were further controlled for body mass index, the positive association was only slightly attenuated (RR = 1.83; 95% CI: 1.12, 2.99). Among past and current postmenopausal hormone users, no significant associations were found. Similar but slightly weaker associations were observed between waist:hip ratio and breast cancer risk. These data suggest that greater waist circumference increases risk of breast cancer, especially among postmenopausal women who are otherwise at lower risk because of never having used estrogen replacement hormones. (+info)