Inhibition of alcohol-associated colonic hyperregeneration by alpha-tocopherol in the rat

BACKGROUND

Chronic alcohol consumption results in colorectal mucosal hyperregeneration, a condition associated with an increased risk for colorectal cancer. Possible mechanisms may involve the effects of acetaldehyde and/or free radicals generated during alcohol metabolism. Vitamin E is part of the antioxidative defense system, and its concentration is decreased or its metabolic utilization increased in various tissues after chronic alcohol consumption. We wondered whether alpha-tocopherol supplementation may prevent ethanol-induced colorectal cell cycle behavior and whether these changes were related to alterations in protein synthesis.

METHODS

Five groups of male Wistar rats, each consisting of 14 animals, received liquid diets as follows: group 1, alcohol; group 2, alcohol + alpha-tocopherol; group 3, control (i.e., isocaloric glucose); group 4; control (i.e., isocaloric glucose) + alpha-tocopherol. Group 5 was fed a solid chow diet ad libitum. After 4 weeks of feeding, immunohistology was performed with anti-proliferating cell nuclear antigen (PCNA) or anti-BCL2 antibodies. Fractional (k(s)) and absolute (V(s)) rates of protein synthesis and rates of protein synthesis relative to RNA (k(RNA)) and DNA (k(DNA)) were measured with a flooding dose of L-[4-3H] phenylalanine with complementary analysis of protein and nucleic acid composition.

RESULTS

The PCNA index was increased significantly in the colon after ethanol administration compared with controls (ethanol, 10.3 +/- 2.3 vs. control, 6.51 +/- 1.6% PCNA positive cells, p < 0.05), although neither the protein, RNA, and DNA concentrations nor k(s), k(RNA), k(DNA), and V(s) were affected. This increase in PCNA index was significantly diminished by coadministration of alpha-tocopherol (ethanol + alpha tocopherol, 7.86 +/- 1.71% PCNA positive cells, p < 0.05) without significant alterations in protein synthetic parameters. A similar result was obtained for the PCNA index in the rectal mucosa (ethanol, 14.6 +/- 4.4 vs. control, 12.1 +/- 4.2% PCNA positive cell), although this did not reach statistical significance. Neither ethanol nor alpha tocopherol feeding had any significant effect on BCL-2 expression in the colorectal mucosa. As with the colon, protein synthetic parameters in the mucosa were not affected by alcohol feeding at 4 weeks. These effects on colonic cell turnover without corresponding changes in protein synthesis thus represent a specific localized phenomenon rather than a general increase in anabolic processes in the tissue and reaffirm the hyperregenerative properties of chronic alcohol consumption.

CONCLUSIONS

Alcohol-associated hyperproliferation could be prevented, at least in part, by supplementation with alpha-tocopherol. This may support the hypothesis that free radicals are involved in the pathogenesis of alcohol-associated colorectal hyperproliferation.

[Comparative analysis of lumbar spine degeneration documented by x-rays versus large specimen cryomicrotome sections]

AIM OF THE STUDY

The extent of degenerative changes in the lumbar spine as seen on conventional radiographs is interpreted on the basis of visualized osseus structures and indirect signs such as diminution of disc height. In order to analyze the accuracy of these interpretations we compared and correlated different stages of degeneration in conventional radiographs with cuts of large-specimen cryomicrotome sections (LSCS), offering a direct macroscopic vision of the degenerative anatomic features.

METHOD

A total of 50 human cadaver lumbar spines with 251 spine segments (Th 12 - S1) was investigated by plain radiograms and LSCS. The degenerative changes were differentiated into 5 stages for both diagnostic measures. Criteria for radiological degeneration were: diminution of disc space, presence of osteophytes and sclerosis of the endplates. Degenerative changes as seen by LSCS were evaluated by the following features: cracks in the endplate, bleeding into the intervertebral disc, alignment of the annulus fibrosus fibres and osseous alterations in the spine segment.

RESULTS

Complete matches of the evaluated radiological and macroscopic stages of degeneration were observed in 206 cases. A difference of 1 degree on the degeneration scale was registered in 42 segments, whereas a difference of 2 degrees was seen in 3 cases. The correlation coefficient between the degeneration stages of the two diagnostic measures scored rho = 0.883.

CONCLUSION

The comparison of the different degrees of degeneration in the lumbar spine as evaluated by both plain radiographs and LSCS revealed a good correlation.

New sensor based on fibre optics for measurement of heart movement

Innovative fibre-optic sensor technology for measuring the movement of the myocardial walls, and from this the heart chamber volumes, was developed. An optical fibre, with a mirror at its end, is inserted into a catheter located in the heart. An opto-electrical control unit positioned outside the heart contains both the light source and the signal receiver. It generates and couples the light into the fibre and transforms and analyses the reflected signal. With such a system, the movement of the cardiac wall can be continuously measured during each cycle, because the fibre moves synchronously with the heart, and this movement bends the fibre, changing the optical attenuation. Experiments where the fibres were wound around metal cylinders of different diameters revealed a maximum sensitivity of 4% mm(-1), diameter. The noise signal corresponded to about 1% of the diameter. First tests in a working pig heart showed a high correspondence of the fibre signal with cardiac parameters. Although these tests are promising, further long-term, extensive experiments in preclinical test devices, and later in clinical tests, must be carried out before the new sensor is used in clinical practice. The fibre-optic technique could be used in monitoring devices, assist devices, pacemaker systems or cardioverter defibrillators.

OPS imaging of human microcirculation: a short technical report

Despite the pivotal role of microcirculation in numerous diseases, techniques for the direct assessment of human microcirculation are limited. A new approach based on orthogonal polarization spectral (OPS) imaging (Cytoscan microscope) allows noninvasive observation of human microcirculation in all accessible tissue surfaces. Limitations remain: application of pressure with the instrument affects blood flow, lateral movement of tissue precludes continuous investigation of a given microvascular region, and blood flow velocities above 1 mm/s cannot be measured. We addressed these problems by (a) constructing an attachment to the probe, preventing direct contact of the instrument with the observed tissue area and allowing fixation of the tissue, and (b) implementing a double-flash spatial correlation technique extending the measuring range for blood flow velocities up to approximately 40 mm/s. The modified approach was tested in vitro and in vivo. Velocity readings correlated well with velocities of an external standard (r(2) = 0.99, range 1.9-33.8 mm/s). Pulsatile flow patterns synchronous with heart rate with maximal velocities of about 10 mm/s could be detected in arterioles of the human sublingual mucosa. The modified instrument may prove useful to investigate the microcirculation in the context of research, diagnosis and therapy control.

The effect of combination treatment with acarbose and glibenclamide on postprandial glucose and insulin profiles: additive blood glucose lowering effect and decreased hypoglycaemia

This study compared the effects of acarbose plus glibenclamide combination therapy with acarbose or glibenclamide treatment alone on postprandial blood glucose, serum insulin and C-peptide levels, and the tendency to develop hypoglycaemia. A total of 84 patients with Type 2 diabetes (fasting blood glucose: 120-180 mg/dl; postprandial blood glucose: 140-240 mg/dl) was included in this two-centre, double-blind, double-dummy, placebo-controlled study. Patients were randomised to one of 4 treatment groups: acarbose (100 mg); glibenclamide (3.5 mg); acarbose plus glibenclamide; or placebo. Treatment was administered before a standard breakfast, and fasting (07.30 h, 08.00 h) and postprandial (09.00, 10.00, 11.00, 12.00 h) blood glucose, serum insulin and C-peptide levels were determined. Acarbose plus glibenclamide treatment significantly reduced the mean increase in postprandial blood glucose levels (23.7+/-17.3 mg/dl) compared with either acarbose (58.4+/-31.6 mg/dl), glibenclamide (56.9+/-42.8 mg/dl) or placebo (101.6+/-49.2 mg/dl) (p<0.05 for all). Serum insulin levels (mean AUC(7.30-12 h)) observed with acarbose plus glibenclamide combination therapy were significantly lower than those observed with glibenclamide monotherapy (243.5+/-161.1 vs 383.4+/-215.8 hr x microU/ml; p=0.02), and comparable with the values seen with placebo (226.0+/-166.6 hr x microU/ml), suggesting that acarbose modifies the insulin secretion induced by glibenclamide. Glibenclamide monotherapy resulted in a significantly higher rate of decrease in blood glucose level than with acarbose plus glibenclamide (71.8+/-29.9 vs 46.2+/-18.0 mg/dl x h(-1); p=0.0003), and blood glucose levels at 11.00 h were also markedly lower with glibenclamide (84.4+/-29 mg/dl) than acarbose plus glibenclamide (102.0+/-41 mg/dl), suggesting a reduced tendency for hypoglycaemic episodes with acarbose plus glibenclamide than with glibenclamide alone. In all, 6 (29%) hypoglycaemic episodes occurred with glibenclamide, 2 (10%) with acarbose plus glibenclamide and none with acarbose. Acarbose plus glibenclamide combination therapy results in an additive glucose lowering effect and reduced risk for hypoglycaemia. Acarbose modifies the insulin secretion induced by glibenclamide, which explains the lower risk of hypoglycaemia compared with glibenclamide monotherapy.

Cariporide (HOE 642) attenuates leukocyte activation in ischemia and reperfusion

Cariporide (HOE 642) ameliorates myocardial ischemia/reperfusion (I/R) injury, by the well established reduction of cytosolic [Ca(2+)] in cardiac myocytes through inhibition of Na(+)/H(+) exchange. However, postischemic inflammation also contributes to I/R injury. We tested the hypothesis that cariporide also modulates the inflammatory response. The effect of cariporide on L-selectin expression by human leukocytes in vitro and leukocyte adhesion and emigration in the reperfused rat cremaster muscle in vivo were studied. The rat cremaster muscle was exteriorized for intravital videomicroscopy, induction of ischemia (90 min), and reperfusion (90 min). Eleven rats were pretreated with cariporide (9 mg/kg body weight IV) whereas 11 rats received saline. Leukocyte adhesion was quantified offline. Human venous blood was incubated with cariporide (3 micromol/L) or saline, stimulated with formyl- methionine-leucine-phenylalanine (10(-10)-10(-6) mol/L), and granulocyte L-selectin expression was analyzed by flow cytometry. Cariporide reduced leukocyte rolling and adhesion by approximately 35% and 45%, respectively, after 30 min of reperfusion. Leukocyte extravasation was decreased by approximately 85% after 90 min. Cariporide increased L-selectin shedding at each formyl-methionine-leucine-phenylalanine concentration, reducing the 50% effective dose from 9.95 to 4.68 nmol/L. Thus, cariporide may ameliorate I/R injury not only by the known reduction of cytosolic [Ca(2+)] in cardiomyocytes, but also by attenuating leukocyte-dependent inflammatory responses. Promotion of L-selectin shedding from activated leukocytes may present a mechanism underlying this newly detected effect.

IMPLICATIONS

This study provides evidence that inhibition of Na(+)/H(+) exchange by cariporide (HOE 642) attenuates the postischemic inflammatory response. Leukocyte adhesion and emigration, assessed by in vivo microscopy, were markedly reduced in rat cremaster muscle, possibly because of increased L-selectin shedding of activated leukocytes as demonstrated by flow cytometry.

Altered distribution of lipid-soluble antioxidant vitamins in juvenile sturgeon exposed to waterborne ethynylestradiol

Studies in mammals have shown that exposure to estrogenic compounds can affect lipid metabolism and plasma concentrations of lipid-soluble vitamins. However, the potential for estrogenic contaminants to induce these effects in fish has not yet been examined. The ability of the estrogen analog ethynylestradiol (EE2) to alter concentrations of the lipid-soluble vitamins A and E in plasma, liver, and kidney was investigated in juvenile lake sturgeon (430 +/- 20 g). The EE2 was delivered to the sturgeon in the tank water at nominal concentrations of 0 (control), 15, 60, or 125 ng EE2/L for a period of 25 d. Concentrations of the egg yolk precursor, vitellogenin, increased dose dependently in plasma. Plasma vitamin E (tocopherol), A1 (retinol), and A2 (dehydroretinol) were elevated by the two highest EE2 treatments compared with the controls. Esterified storage forms of vitamin A were marginally lower in the livers of fish from the highest EE2 dose group, but vitamin E levels in the liver were not significantly affected. Concentrations of vitamin E and vitamin A were significantly depleted in the kidney of fish from the two highest EE2 dose groups. Total lipid content was elevated in the gonad of fish treated with the highest dose of EE2 compared with the controls. Altered lipid and vitamin distribution may be induced by estrogen to facilitate gonadal maturation in sturgeon. Results from these studies indicate that an examination of the implications for vitamin depletion by estrogenic contaminants in juvenile fish is warranted.

[Importance of intraoperative parathormone measurements in primary hyperparathyroidism with 5-gland hyperplasia]

While intraoperative parathormone measurements are mandatory for unilateral operations of primary hyperparathyroidism (pHPT), its value for treatment of parathyroid hyperplasia is regarded as insufficient. We report a case of a pHPT with hyperplasia of five glands, in which only the intraoperative analysis of parathormone detected the remaining fifth hyperparathyroid gland after extirpation of four enlarged parathyroid glands. We describe technical problems involved in the tests available today and how the results of the intraoperative parathormone test need to be interpreted. As several factors can influence the decrease in parathormone concentration, a kinetic analysis may be more accurate in assessing the adequacy of resection. Therefore, intraoperative parathormone measurements are especially useful and important for adequate surgical therapy for pHPT with parathyroid hyperplasia.

Desmopressin impairs microcirculation in donor pancreas and early graft function after experimental pancreas transplantation

BACKGROUND

Protective effects of desmopressin in brain dead organ donors oppose reports on a hypercoagulatory potential and an increased leukocyte-endothelial interaction (LEI) after application of the drug. The aim was to evaluate the effect of desmopressin on organ donor's pancreas and early graft function.

METHODS

Donor microcirculation was evaluated via intra-vital microscopy (IVM) in 24 BR (di/di) rats with central diabetes insipidus, randomly assigned to groups I (control without desmopressin application), II (single i.v. application, no pretreatment) or group III (single i.v. desmopressin application, s.c. pretreatment for 3 days). Microcirculation in recipients was evaluated 1 hr and 6 hr after syngenic pancreas transplantation. Groups III and I served as organ donors. After IVM specimens were taken for histology and immunohistochemistry.

RESULTS

Desmopressin in II vs. I led to temporarily (30') increased LEI (Sticker 274.3+/-87.7 vs. 76.5+/-31.1/mm2 endothelial surface; P<0.01) and impaired microcirculation (MCEV 0.43+/-0.07 vs. 0.99+/-0.06 mm/s; P<0.01). Repeated application reduced MCEV and increased LEI for up to 12 hr. Histology in I vs. III showed increased inflammation (n.s.), necrosis (P<0.05) and vacuolization (P<0.01). Immunohistochemistry revealed increased endothelial P-selectin 20' after application. 6 hr after reperfusion organs from III showed reduced MCEV and increased LEI (P<0.01).

CONCLUSION

Repeated application of desmopressin impairs graft microcirculation. Perfusion of the pancreas is significantly reduced at the beginning of organ tissue conservation as well as after reperfusion. These disturbances might partly be due to observed endothelial P-selectin expression. Application of desmopressin up to 12 hr prior to organ explantation may impact graft quality.

Mediator, not holoenzyme, is directly recruited to the heat shock promoter by HSF upon heat shock

Activators of RNA polymerase II (Pol II) transcription have been shown to bind several coactivators and basal factors in vitro. Whether such interactions play a primary regulatory role in recruiting these factors to activator-associated chromosomal target sites in living cells remains unclear. Here, we show that upon heat shock the Pol II-free form of Mediator is rapidly recruited to HSF binding sites. Unlike the TAFs and Pol II, the interaction between Mediator and HSF on chromosomal loci is direct and mechanistically separable from the preinitiation complex assembly step. Therefore, the activator-Mediator interaction likely underlies the initiation of signal transfer from enhancer-bound activators to the basal transcription machinery.

Surgical treatment of parathyroid carcinoma (Review)

Cancer of the parathyroid gland is rare and most patients suffer from hyperparathyroidism (HPT). Therefore it is often difficult to distinguish between benign HPT and malignant disorders. Prognosis as well as therapeutic approaches are still limited. Surgical treatment should be considered the therapy of choice for primary and recurrent manifestation of parathyroid carcinoma. The initial operation includes en-bloc resection of the tumor and the ipsilateral thyroid lobe. Surgery may cure some patients, but is often only palliative and aims to control hypercalcemia. In some patients hypercalcemia may be refractory to repeated surgery and medical treatment can provide short- or middle-term effects.

Linkage of oxidative and nonoxidative ethanol metabolism in the pancreas and toxicity of nonoxidative ethanol metabolites for pancreatic acinar cells

BACKGROUND

Alcohol abuse is a major cause of pancreatic damage. Recent experimental evidence suggests that fatty acid ethyl esters (FAEE), nonoxidative ethanol metabolites, injure pancreatic acinar cells. Linkage between oxidative and nonoxidative metabolism of ethanol in the pancreas may contribute to increased FAEE levels.

METHODS

To study the association between oxidative and nonoxidative ethanol metabolism, FAEE concentration and FAEE synthase activity in rat pancreatic and liver homogenates incubated with ethanol were evaluated with and without inhibitors of oxidative ethanol metabolism. For toxicity studies, trypsinogen activation peptide synthesis as a measure of pancreatic cell injury was quantitated in unstimulated and cerulein-stimulated isolated pancreatic acinar cells incubated with ethanol or FAEE.

RESULTS

Inhibition of oxidative ethanol metabolism results in a 2- to 3-fold increase in nonoxidative ethanol metabolism to FAEE in pancreas and in liver. Both ethanol and FAEE induce increased intracellular trypsinogen activation by more than 50% in the presence of physiologic concentrations of cerulein in vitro.

CONCLUSIONS

These findings demonstrate that the inhibition of oxidative ethanol metabolism results in an increase in flux through the nonoxidative pathway and support the proposition that alcohol-induced pancreatic injury is mediated at least in part by FAEE, which are important products of pancreatic ethanol metabolism.

Biological implications of tumor cells in blood and bone marrow of pancreatic cancer patients

BACKGROUND

Patients with pancreatic cancer often have tumor recurrence despite curative resection. Cancer cells detected in blood or bone marrow at the time of diagnosis may relate to tumor stage and to prognosis. Recent research emphasis has centered on tumor cells in bone marrow aspirates, but whether these represent early micrometastases or blood-borne cells in transit is unknown.

PATIENTS AND METHODS

We developed a specific immunocytochemical assay that evaluated more than 5.3 x 10(6) extracted mononuclear cells per sample of blood and bone marrow and that could identify a single tumor cell in that population. The assay was applied to samples of blood and bone marrow from 105 patients with pancreatic cancer and 66 controls. The prevalence of isolated tumor cells was compared with Union Internationale Contre le Cancer (UICC) stage. A multivariate Cox regression analysis for survival was performed.

RESULTS

Pancreatic cancer cells were detected in 26% of blood samples and in 24% of bone marrow specimens. Specificity for cancer was 96%. The prevalence of isolated tumor cells in patients with proven resectable cancer was 9% in blood and 13% in bone marrow. The prevalence increased with UICC tumor stage in blood (P =.04) but not in bone marrow (P =.52) and correlated in blood with resectability (P =.02), progression of disease (P=.08), and peritoneal dissemination (P =.003). While survival correlated significantly with tumor stage (P <.001) and isolated tumor cells in blood correlated with tumor stage, the finding of cancer cells in blood or bone marrow, or both, was not independently associated with survival in patients with pancreatic cancer.

CONCLUSIONS

Isolated tumor cells in blood but not bone marrow reflect the stage of growth and spread of pancreatic cancer, particularly in the peritoneal cavity. The findings are consistent with cells in bone marrow aspirates being in transit, not implanted. These disseminated cancer cells may be the consequence, rather than the cause, of progression.