Neurotoxicity of glucocorticoids in the primate brain

Severe and prolonged physical and psychological stress is known to cause brain damage; long-term torture victims in prison have later developed psychiatric disorders and cerebral cortical atrophy observed in CT scans (Jensen, Genefke, Hyldebrandt, Pedersen, Petersen, and Weile, 1982). In nonhuman primates, we observed degeneration and depletion of the hippocampal neurons in African green monkeys that had been severely abused by cagemates and died with complications of multiple gastric ulcers and adrenal cortical hyperplasia (Uno, Tarara, Else, Suleman and Sapolsky, 1989). In our previous studies the administration of dexamethasone (DEX) (5 mg/kg) to pregnant rhesus monkeys at 132 to 133 days of gestation induced degeneration and depletion of the hippocampal pyramidal and dentate granular neurons in the brains of 135-gestation-day fetuses, and these changes were retained in the brains of fetuses at near term, 165 days of gestation (Uno, Lohmiller, Thieme, Kemnitz, Engle, Roecker, and Farrell, 1990). We also found that implantation of a cortisol pellet in the vicinity of the hippocampus in adult vervet monkeys induced degeneration of the CA3 pyramidal neurons and their dendritic branches (Sapolsky, Uno, Rebert, and Finch, 1990). Thus, hippocampal pyramidal neurons containing a high concentration of glucocorticoid receptors appear to be highly vulnerable to either hypercortisolemia caused by severe stress or to exposure to exogenous glucocorticoids. To study the long-term postnatal sequelae of prenatal brain damage, eight rhesus monkeys were treated with either DEX (5 mg/kg), 5 animals, or vehicle, 3 animals, at 132 to 133 days of gestation. After natural birth, all animals lived with their mothers for 1 year. At 9 months of age, we found that DEX-treated animals had significantly high plasma cortisol at both base and post-stress (isolation) levels compared to age-matched vehicle-treated animals. Magnetic resonance images (MRI) of the brain at 20 months of age showed an approximately 30% reduction in size and segmental volumes of the hippocampus in DEX-treated compared to vehicle-treated animals. Measurements of whole brain volume by MRI showed no significant differences between DEX and vehicle groups. Prenatal administration of a potent glucocorticoid (DEX) induced an irreversible deficiency of the hippocampal neurons and high plasma cortisol at the circadian baseline and post-stress levels in juvenile rhesus monkeys. These results suggest that the hippocampus mediates negative feedback of cortisol release; a lack or deficiency of the hippocampal neurons attenuates this feedback resulting in hypercortisolemia.(ABSTRACT TRUNCATED AT 400 WORDS)

Mating in the rhesus monkey (Macaca mulatta) after conception and its relationship to oestradiol and progesterone levels throughout pregnancy

Behavioural and hormonal data were collected throughout pregnancy in captive rhesus monkeys. Heterosexual pairs observed in daily time-limited mating tests showed two distinct periods of increased sexual interaction, as measured by the incidence of ejaculation. One period was coincident with the preovulatory oestradiol peak, while the other occurred between the 6th and 10th weeks of pregnancy. The positive relationship found during the menstrual cycle between the ratio of circulating oestradiol: progesterone and degree of sexual activity continued for the first 8 weeks of pregnancy. However, sexual activity ceased in the second half of pregnancy despite a continued high oestradiol: progesterone ratio.

Mouse alpha-fetoprotein-specific DNA-based immunotherapy of hepatocellular carcinoma leads to tumor regression in mice

BACKGROUND & AIMS

alpha-Fetoprotein (AFP) is a tumor-associated protein that is frequently expressed at high levels in hepatocellular carcinoma (HCC). The aim of the study was to characterize self-reactive cytotoxic T lymphocytes (CTLs) directed against murine AFP (mAFP) after DNA-based immunization in mice.

METHODS

To study CTL responses, mAFP-expressing recombinant vaccinia viruses were generated. An HCC tumor model was established in C57L/J mice by injection of syngeneic endogenously mAFP-expressing Hepa1-6 cells.

RESULTS

Gene gun and intramuscular coimmunizations of DNA expression vectors encoding mAFP with plasmids encoding murine interleukin (IL)-12, granulocyte-macrophage colony-stimulating factor, or IL-18 induced weak CTL activity against mAFP in different mouse strains. Some mice developed anti-mAFP antibody responses, suggesting breaking of immunologic ignorance. No hepatocyte damage was detectable despite low-level endogenous hepatic mAFP expression. Therapeutic immunizations of mice bearing mAFP-expressing murine HCCs induced partial regression of tumors. A significant survival benefit was observed in mice immunized with mAFP expression vector DNA but not in untreated mice or in mice immunized with mock/cytokine plasmid DNA.

CONCLUSIONS

The data show that AFP may be used as a potential self tumor antigen to induce CTL and CD4(+) T cell-mediated regression of AFP-expressing HCC by DNA-based immunization.

Lipid peroxidation and glutathione metabolism in chronic pancreatitis

In experimental models of pancreatitis lipid peroxidation products are increased possibly because of an enhanced generation of oxygen radicals. The purpose of this study was to determine whether lipid peroxidation products are increased in pancreatic tissue and serum of patients suffering from chronic or acute pancreatitis. In 20 patients undergoing operative treatment for chronic (n = 11) and acute pancreatitis (n = 9) the levels of malondialdehyde, conjugated dienes, and reduced and oxidized glutathione were determined in resected tissue samples. The excised tissue was examined and evaluated by light microscopy. Shortly before operation the serum concentrations of malondialdehyde, alpha-amylase, and lipase were measured. Pancreatic tissue from eight organ donors who had no abdominal trauma or pancreatic disease served as control. In chronic pancreatitis, conjugated dienes as well as malondialdehyde concentrations in the tissue were significantly elevated. Reduced glutathione was significantly decreased, suggesting glutathione depletion due to oxidative stress. In acute pancreatitis only the tissue and serum malondialdehyde levels were significantly high, whereas conjugated dienes remained within the normal range. Serum malondialdehyde levels correlated significantly with tissue concentrations (r = 0.76; p < 0.05) but not with the clinical course or the enzyme levels. In chronic pancreatitis, the increased tissue levels of lipid peroxidation products and the changes in glutathione metabolism suggest ongoing peroxidation of lipids due to an enhanced generation of oxygen radicals. In hemorrhagic necrotizing pancreatitis, however, oxygen radical-induced lipid peroxidation cannot be proven. Apparently, other pathomechanisms are involved in the development of the severe tissue damage.

The alphavbeta6 integrin is a highly specific immunohistochemical marker for cholangiocarcinoma

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) are common primary hepatic malignancies. Their immunohistological differentiation using specific markers is pivotal for treatment and prognosis. We found alphavbeta6 integrin strongly upregulated in biliary fibrosis, but its expression in primary and secondary liver tumours is unknown. Here, we aimed to evaluate the diagnostic applicability of alphavbeta6 integrin in differentiating primary liver cancers.

METHODS

Expression of alphavbeta6 integrin was evaluated in liver tissues from patients with CC, HCC, fibrolamellar HCC, combined CC/HCC, hepatic metastases of colorectal and pancreatic carcinomas, primary sclerosing cholangitis (PSC), and in human primary and tumour-derived liver cell lines by immunohisto- and cytochemistry, and by TaqMan PCR. Diagnostic performance of the beta6 subunit was compared with CK7, CK20, and HepPar 1.

RESULTS

In CC cells beta6 mRNA levels were induced 125-fold compared to primary cholangiocytes, while it was completely absent in hepatoma cells. In human tissues, beta6 transcripts were more than 100-fold upregulated in CC compared to normal liver. By immunohistochemistry, 88% of CC, 50% of PSC, 13% of colorectal carcinoma metastases, and 80% of pancreatic carcinoma metastases presented alphavbeta6, whereas all HCC, combined CC/HCC and fibrolamellar HCC stained negative. Specificity of beta6 immunohistochemistry for CC (100%) surpassed all other tested markers and sensitivity was equal to CK7 (86% vs. 90%).

CONCLUSION

The alphavbeta6 integrin is strongly expressed in human CC but not in HCC and therefore can be considered as a specific immunohistochemical marker in the differential diagnosis of primary liver tumours.

Improvement in the long-term stability of an amperometric glucose sensor system by introducing a cellulose membrane of bacterial origin

Classical amperometric glucose sensors that use cellulose membranes of wood origin (Cuprophan) suffer from the fact that their long-term stability in blood is short; therefore, their clinical use is limited. In the present study, a classical amperometric glucose sensor was covered with a bacterial cellulose (BC) membrane. Its surface in comparison to that of the classical glucose sensor (Cuprophan) and its long-term stability were tested in vitro and in vivo. The surface element composition was approximately 44% oxygen and approximately 56% carbon in both membranes and thus typical for cellulose. BC membranes exhibited fiber structure, whereas cup membranes did not. There was also a qualitative difference in protein adsorption between both membranes on exposure to bovine serum albumin. Treatment with Trogamid of one site of the BC membranes allowed linear glucose detection between 0 and 40 mM. Hemocompatibility of BC membranes was improved in comparison to cup membranes on the basis of complement activation (C3a and C5a). In diluted blood (1:10), the BC-covered sensor exhibited a long-term stability of more than 200 h; in undiluted blood it was stable for about 24 h, which is about 6-7 times longer than the stability of the classical Cup membrane-covered sensor. In in vivo studies, where the BC membrane-covered sensors were connected to the jugular vein of rats, blood glucose levels could be monitored for at least 24 h. In summary, the use of a modified bacterial cellulose membrane to cover the classical amperometric glucose sensor significantly improves the sensor's long-term stability both in vitro and in vivo.

Optimized biosensor for whole blood measurements using a new cellulose based membrane

We used bacterial cellulose membranes as outer membranes for glucose sensors based upon amperometric detection of glucose oxidase reaction products. We found a long-term stability in 1:10 diluted blood of about 200 h. In comparison a Cuprophan membrane was stable for only 30 h under the same conditions. Comparing the two membranes in undiluted human blood, a similar trend was found in the long-term stability; Cuprophan was stable for only 3-4 h and the glucose sensor with the bacterial cellulose membrane was stable for more than 24 h. In addition, the measuring range of the glucose sensor could be extended up to 170 mM glucose by treating the bacterial cellulose membrane with a polyamide.

[Cercaria dermatitis (swimmer's itch). Case report of cercaria dermatitis caused by Trichobilharzia (Digena, Schistosomatidae)]

A 63-year-old woman developed a pruritic exanthema on the extremities after one hour of work in her garden pond in Planegg, Southern Bavaria. As the appropriate vectors (ducks and snails) were present, we made the tentative diagnosis of cercarial dermatitis (swimmer's itch). By different serological methods (cercarial fluorescent antibody test, cercarial Hüllen reaction, circumoval precipitin test) antibodies against cercariae could be demonstrated in the serum of the patient 14 days later. Cercarial dermatitis appears worldwide, but in Central Europe the disease is often not recognized.

Cine magnetic resonance imaging of the small bowel: comparison of different oral contrast media

PURPOSE

To evaluate several substances regarding small bowel distension and contrast on balanced steady-state free precession (bSSFP) cine magnetic resonance (MR) images.

MATERIAL AND METHODS

Luminal contrast was evaluated in 24 volunteers after oral application of two different contrast agent groups leading to either bright lumen (pineapple, blueberry juice) or dark lumen (tap water, orange juice) on T1-weighted images. Bowel distension was evaluated in 30 patients ingesting either methylcellulose or mannitol solution for limiting intestinal absorption. Fifteen patients with duodeno-jejunal intubation served as the control. Quantitative evaluation included measurement of luminal signal intensities and diameters of four bowel segments, qualitative evaluation assessed luminal contrast and distension on a five-point scale.

RESULTS

Quantitative and qualitative evaluation of the four contrast agents revealed no significant differences regarding luminal contrast on bSSFP images. Quantitative evaluation revealed significantly lower (P<0.05) small bowel distension for three out of four segments (qualitative evaluation: two out of four segments) for methylcellulose in comparison to the control. Mannitol was found to be equal to the control.

CONCLUSION

Oral ingestion of tap water or orange juice in combination with mannitol is recommended for cine MR imaging of the small bowel regarding luminal contrast and small bowel distension on bSSFP sequences.

Renin-dependent water intake in hypovolemia

The role of the renin-angiotensin system as a mediator of water intake, induced by hypovolemia after polyethylene glycol (PEG) injection, was investigated. Blockade of angiotensin I converting enzyme and of angiotensin receptors was used as a pharmacological tool. A significant reduction of water intake was observed when angiotensin I converting enzyme was inhibited by captopril and enalapril. In PEG-treated rats with blockade of angiotensin I converting enzyme, hypertonic saline injection continued to elicit substantial drinking. Normalization of low blood pressure by vasopressin infusions in PEG and captopril treated rats did not interfere with the antidipsogenic effectiveness of converting enzyme blockade. The angiotensin II receptor antagonist, saralasin, also reduced PEG-induced drinking although less effectively than converting enzyme inhibitors. We conclude that water intake due to isotonic depletion of the extracellular fluid compartment may depend on the activity of the renin-angiotensin system.

Use of an ultrasonic blood flow monitor for determining fetal viability in the rhesus monkey (Macaca mulatta). A preliminary study

Ultrasonic stethoscopy proved to be a reliable and convenient technique for determing fetal viability in Macaca mulatta. Examinations, begun at day 150 of gestation in 33 monkeys and between days 32 and 58 in four other animals, were repeated at intervals of one to seven days. The earliest time of detecting blood flow in the fetal placenta was 42 days of gestation, fetal heart sounds geing discerned later. Three types of fetal cardiac rhythms were recognized: (1) a constant rate during most of pregnancy, (2) fluctuations associated with uterine contractions during labor, and (3) sudden transient bradycardia during violent rotations of the cephalically presented fetus.

Analysis of lymphocyte shape by visual classification, calculated measures of shape or light scattering

Direct visual assays, calculated measures of shape (Dunn and Brown, 1986) and light scattering were applied to detect shape changes and to identify human peripheral blood lymphocytes displaying different shapes (e.g., spherical cells, polarized cells, non-polar cells with surface projections). Spherical cells could be distinguished from polarized cells and from non-polar cells with surface projections by means of calculated measures of shape obtained from outline drawings, the dispersion parameter being more efficient than extension or elongation parameters. Median values for elongation and extension of polarized cells vs. non-polar cells with surface projections differed significantly provided the cell populations consisted entirely of one particular morphological class. However, if the proportion of cells changing shape is small, this may not be detectable by a significant change in the median values. Therefore, we attempted to apply calculated shape factors to identify individual cells showing a particular type of shape change. Spherical cells could be distinguished relatively easily from non-spherical cells on the basis of the dispersion values. However, it was not possible to distinguish unequivocally between polarized cells and non-polar cells with surface projections because the values overlap to a great extent. For this purpose the visual classification was found to be more reliable. Preliminary experiments with light scattering showed that median values for right angle scatter or forward angle scatter are not sensitive enough to permit the detection of a small proportion of cells changing shape.

[The role of oxygen radicals in acute pancreatitis. Clinical and experimental results of therapy with free radical scavengers]

Numerous studies support the theory that oxygen free radicals (OR) are involved in the development of tissue damage in all forms of experimental acute pancreatitis. OR are generated in an early phase of the disease before tissue damage is detectable by histology. The pathomechanism that leads to this oxidative stress is not fully understood. The efficacy of scavenger treatment was clearly proven in most models of experimental acute pancreatitis. In first clinical trials applying antioxidant treatment with selenium show favorable results in reducing the lipidperoxidation and improving the antioxidant status. However these preliminary results but must be supported in a larger series of patients to allow proper evaluation of patient outcome.

Vacuolar occupancy is crucial for cell elongation and growth regardless of the underlying mechanism

In the physiological range, the phytohormone auxin inhibits the growth of underground tissues. In the roots of Arabidopsis thaliana, cell size inhibition has been shown to be accompanied by auxin-mediated reduction of vacuole size. A tonoplast-localized protein family (Networked 4) with actin-binding capacity was demonstrated to modulate the compactness of the vacuole. Overexpression of NET4A led to smaller, more spherical and compact vacuoles, which occupied less cellular space compared to wild type. This reduction of vacuolar occupancy is similar to the observed auxin-induced decrease in occupancy, albeit there are enormous morphological differences. Here, we show that a net4a net4b double mutant and a NET4A overexpressor line are still sensitive to auxin-induced vacuolar constrictions. However, the overexpressor showed a partial auxin resistance accompanied by more compact vacuoles, thereby indicating an additional regulatory mechanism. Furthermore, we show that other NET superfamily members do not compensate for the loss of NET4A and NET4B expression on the transcriptional level. This leads us to hypothesize that regulation of vacuole size is a general mechanism to regulate cell expansion and that other players besides NET4 must participate in regulating the vacuole-cytoskeleton interface.

Fatal intestinal pseudo-obstruction in brown bowel syndrome

A 52-year-old man, suffering for years from malabsorption due to endemic sprue, developed progressive bowel dysfunction, ie, recurrent ileus and intestinal pseudo-obstruction. Because of partial volvulus formation, ileocecal resection was performed. Histopathologic examination of the resected specimen revealed signs of advanced brown bowel syndrome, with excessive deposits of ceroid-lipofuscin in, and a considerable loss of, smooth-muscle cells and myofibrils. The patient died after surgery, and at autopsy a systemic ceroid lipofuscinosis of smooth-muscle cells was detected. Neuronal ceroid lipofuscinosis was not observed. Serious and eventually fatal bowel dysfunction is rarely seen in brown bowel syndrome, but may occur in advanced stages. Since treatment with vitamin E appears to exert a favorable effect, early diagnosis of brown bowel syndrome seems to be very important.