Changes in the total number of neuroglia, mitotic cells and necrotic cells in the anterior limb of the mouse anterior commissure following hypoxic stress. (65/174666)

The effects of hypoxic stress (390 mmHg) on the total number of glia, cell division, and cell death in the anterior limb of the anterior commissure were studied. There was a significant (P less than 0-01) fall in the total number of glia following exposure to hypoxia at 390 mmHg for two days. No significant change was observed in the total number of glia between the hypoxic and recovery group one week after return to sea level (ca. 760 mmHg). No change was observed in the number of mitotic figures in the control, hypoxic or recovery groups, but significant falls were observed in the mean number of necrotic cells between both the control and hypoxic groups (P less than 0-05) and the hypoxic and recovery groups (P less than 0-012). The decrease in necrotic cells may be due to a large number of elderly and effete cells, which would normally have undergone degeneration over a period of weeks, dying rapidly after the onset of hypoxia, thus temporarily reducing the daily cell death rate.  (+info)

Evidence of improving survival of patients with rectal cancer in france: a population based study. (66/174666)

BACKGROUND: Over the past 20 years there have been many changes in the management of rectal cancer. Their impact on the overall population is not well known. AIMS: To determine trends in management and prognosis of rectal cancer in two French regions. SUBJECTS: 1978 patients with a rectal carcinoma diagnosed between 1978 and 1993. METHODS: Time trends in treatment, stage at diagnosis, operative mortality, and survival were studied on a four year basis. A non-conditional logistic regression was performed to obtain an odds ratio for each period adjusted for the other variables. To estimate the independent effect of the period a multivariate relative survival analysis was performed. RESULTS: Over the 16 year period resection rates increased from 66.0% to 80.1%; the increase was particularly noticeable for sphincter saving procedures (+30.6% per four years, p=0.03). The percentage of patients receiving adjuvant radiotherapy increased from 24.0% to 40.0% (p=0.02). The proportion of patients with Dukes' type A cancer increased from 17. 7% to 30.6% with a corresponding decrease in those with more advanced disease. Operative mortality decreased by 31.1% per four years (p=0.03). All these improvements have resulted in a dramatic increase in relative survival (from 35.4% for the 1978-1981 period to 57.0% for the 1985-1989 period). CONCLUSIONS: Substantial advances in the management of rectal cancer have been achieved, but there is evidence that further improvements can be made in order to increase survival.  (+info)

Chronic radiodermatitis following cardiac catheterisation: a report of two cases and a brief review of the literature. (67/174666)

Cardiac angiography produces one of the highest radiation exposures of any commonly used diagnostic x ray procedure. Recently, serious radiation induced skin injuries have been reported after repeated therapeutic interventional procedures using prolonged fluoroscopic imaging. Two male patients, aged 62 and 71 years, in whom chronic radiodermatitis developed one to two years after two consecutive cardiac catheterisation procedures are reported. Both patients had undergone lengthy procedures using prolonged fluoroscopic guidance in a limited number of projections. The resulting skin lesions were preceded, in one case, by an acute erythema and took the form of a delayed pigmented telangiectatic, indurated, or ulcerated plaque in the upper back or below the axilla whose site corresponded to the location of the x ray tube during cardiac catheterisation. Cutaneous side effects of radiation exposure result from direct damage to the irradiated tissue and have known thresholds. The diagnosis of radiation induced skin injury relies essentially on clinical and histopathological findings, location of skin lesions, and careful medical history. Interventional cardiologists should be aware of this complication, because chronic radiodermatitis may result in painful and resistant ulceration and eventually in squamous cell carcinoma.  (+info)

Role of glucagon on the control of hepatic protein synthesis and degradation in the rat in vivo. (68/174666)

The effect of glucagon on hepatic protein systhesis and proteolysis has been investigated. The intraperitoneal administration of 200 mug of glucagon produced an increase of the polypeptide chains completion time which was maximal 5 min after its administration and approached control values at 20 min. The increase of the polypeptides chains completion time observed at 5 min after the hormone administration represents a 38% inhibition of the hepatic protein synthetic rate. When glucagon was continuously supplied by intravascular infusion, maximal inhibition was attained throughout the experiment. This inhibition of protein synthesis brought about by glucagon was accompanied by an increase in the polyribosomal state of aggregation, indicating that the hormone acts mainly if not exclusively, on the elongation or termination step, or both. The administration of glucagon produced also a progressive increase in the hepatic valine concentration. This increase could not be accounted for the the decrease in plasma valine levels, suggesting that the rise in haptic valine concentration is an expression of hepatic proteolysis rather than the result of an accelerated transport of amino acids across the hepatocyte plasma membrane. The different time sequence in the glucagon-induced effects of protein synthesis and proteolysis suggests that both effects are independent and probably mediated by different mechanisms.  (+info)

Voltage sensors in domains III and IV, but not I and II, are immobilized by Na+ channel fast inactivation. (69/174666)

Using site-directed fluorescent labeling, we examined conformational changes in the S4 segment of each domain of the human skeletal muscle sodium channel (hSkM1). The fluorescence signals from S4 segments in domains I and II follow activation and are unaffected as fast inactivation settles. In contrast, the fluorescence signals from S4 segments in domains III and IV show kinetic components during activation and deactivation that correlate with fast inactivation and charge immobilization. These results indicate that in hSkM1, the S4 segments in domains III and IV are responsible for voltage-sensitive conformational changes linked to fast inactivation and are immobilized by fast inactivation, while the S4 segments in domains I and II are unaffected by fast inactivation.  (+info)

Interleukin-12 is synthesized by mesangial cells and stimulates platelet-activating factor synthesis, cytoskeletal reorganization, and cell shape change. (70/174666)

Preliminary studies indicate the involvement of interleukin (IL)-12 in experimental renal pathology. In the present study, we evaluated whether cultured glomerular mesangial cells are able to produce IL-12 and whether IL-12 may regulate some of their functions, including the cytoskeletal reorganization, the change in cell shape, and the production of platelet-activating factor (PAF). The results obtained indicate that pro-inflammatory stimuli, such as tumor necrosis factor-alpha and bacterial polysaccharides, induce the expression of IL-12 mRNA and the synthesis of the protein by cultured mesangial cells. Moreover, cultured mesangial cells were shown to bind IL-12 and to express the human low-affinity IL-12 beta1-chain receptor. When challenged with IL-12, mesangial cells produced PAF in a dose- and time-dependent manner and superoxide anions. No production of tumor necrosis factor-alpha and IL-8 was observed. Moreover, we demonstrate that IL-12 induced a delayed and sustained shape change of mesangial cells that reached its maximum between 90 and 120 minutes of incubation. The changes in cell shape occurred concomitantly with cytoskeletal rearrangements and may be consistent with cell contraction. As IL-12-dependent shape change of mesangial cells was concomitant with the synthesis of PAF, which is known to promote mesangial cell contraction, we investigated the role of PAF using two chemically different PAF receptor antagonists. Both antagonists inhibited almost completely the cell shape change induced by IL-12, whereas they were ineffective on angiotensin-II-induced cell shape change. In conclusion, our results suggest that mesangial cells can either produce IL-12 or be stimulated by this cytokine to synthesize PAF and to undergo shape changes compatible with cell contraction.  (+info)

One-year survival among patients with acute myocardial infarction complicated by cardiogenic shock, and its relation to early revascularization: results from the GUSTO-I trial. (71/174666)

BACKGROUND: Although 30-day survival is increased in patients with acute myocardial infarction complicated by cardiogenic shock who undergo coronary revascularization, the longer-term outcome in such patients and the duration of benefit from revascularization are unknown. METHODS AND RESULTS: We analyzed 30-day survivors of acute myocardial infarction in the Global Utilization of Streptokinase and Tissue-Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) trial and identified 36 333 who had not had cardiogenic shock (systolic blood pressure <90 mm Hg for >/=1 hour, group 1) and 1321 patients who had shock (group 2). Group 2 patients were older and sicker. At 1 year, 97.4% of group 1 patients were alive versus 88.0% of group 2 (P=0.0001). Among group 2 patients, 578 (44%) had undergone revascularization within 30 days (group 2A) and 728 (56%) had not (group 2B). Revascularization was not required by protocol but was selected by the attending physicians. At 1 year, 91.7% of group 2A patients were alive versus 85.3% of group 2B (P=0.0003). With the use of multivariable logistic regression analysis to adjust for differences in baseline characteristics of shock patients alive at 30 days, revascularization within 30 days was independently associated with reduced 1-year mortality (odds ratio 0.6, [95% confidence interval 0.4, 0.9], P=0.007). CONCLUSIONS: Most patients (88%) with acute myocardial infarction complicated by cardiogenic shock who are alive at 30 days survived at least 1 year. Shock patients who underwent revascularization within 30 days had improved survival at 1 year compared with shock patients who did not receive revascularization, even after adjustment for differences in baseline characteristics between the 2 groups.  (+info)

Differential effects of a segment of slow conduction on reentrant ventricular tachycardia in the rabbit heart. (72/174666)

BACKGROUND: The purpose of this study was to compare differential effects of a segment of slow conduction during ventricular tachycardia (VT) due to depression of the action potential and electrical uncoupling. METHODS AND RESULTS: In 33 Langendorff-perfused rabbit hearts, a ring of anisotropic left ventricular subepicardium was created by a cryoprocedure. Reentrant VT was produced by incremental pacing. Slow conduction in a segment of the ring was created by selective perfusion of the LAD with 10 mmol/L potassium or 0.75 mmol/L heptanol. As a result, VT cycle length increased from 193+/-34 to 235+/-37 ms (potassium) and 227+/-42 ms (heptanol). Reset curves were made by applying premature stimuli proximal to the area of depressed conduction. In a ring of uniform anisotropic tissue, the reset curve was almost completely flat. Electrical uncoupling of part of the ring (nonuniform anisotropy) resulted in a mixed reset curve. In both substrates, early premature beats failed to terminate VT. Depression of part of the ring by increasing K+ resulted in a completely sloped reset curve, indicating a gap of partial excitability. Under these conditions, in 19 of 24 hearts, premature beats terminated VT by conduction block in the high K+ area. CONCLUSIONS: The nature of the area of slow conduction determines the type of reset response and the ability to terminate VT.  (+info)