Biomedical subjects

C Mehler

Publications and source records attributed to C Mehler.

9 recordsLinked to original sources

PubMed2002

Structural brain abnormalities specific to childhood-onset schizophrenia identified by neuroimaging techniques.

This review discusses functional and structural brain abnormalities in childhood-onset schizophrenia identified by neuroimaging techniques. Published literature regarding both morphological and functional neuroimaging is discussed, regarding also the diversity of neuroimaging findings which partly reduces their reliability. The findings in early onset schizophrenia are compared with those of adult patients. The results of long-term investigations of structural abnormalities in early onset schizophrenia are given particular attention. The most consistent findings are ventricular enlargement and reduced total brain volume. Further, volumetric changes in the temporal and frontal cortex, thalamus, basal ganglia and limbic system are reported, as are hemispheric asymmetries and, conversely, reduction of normal differences. Findings regarding the corpus callosum and cerebellum are less consistent. In patients whose schizophrenia commenced in early childhood, the differences were generally more marked than in adolescence- or adult-onset schizophrenia. Atrophy of total brain volume was progressive throughout the course of the disorder. It is probable that neuroanatomical cerebral abnormalities present prior to disease onset play an etiopathogenic role in the development of schizophrenia.

Adolescent↗

PubMed2001

Olanzapine in children and adolescents with chronic anorexia nervosa. A study of five cases.

Psychopathology in severely anorexic patients often seems to be of compulsive and delusional quality rendering therapeutic approaches extremely difficult. With conventional therapeutic regimes failing, administration of the novel antipsychotic olanzapine induced remarkable improvement in five cases reported here. Paranoid ideation concerning body image or weight gain decreased and sedative effects helped to reduce inner tensions and phobia with respect to food intake. Olanzapine, therefore, might represent an important therapeutic tool in anorexic patients who present the following characteristics: long-term history of anorexia nervosa mostly with several hospitalisations, missing perception of their severe state of illness, refusal of therapy, delusional quality of anorexic thinking, risk of discontinuation of therapy with life-threatening consequences.

Adolescent↗

PubMed2000

The diminished postoperative capacity of blood leukocytes to produce IL-6 is associated with high concentrations of IL-6 in the circulation.

Surgical trauma is followed both by a transient increase of interleukin 6 (IL-6) concentrations in the serum and impaired function of circulating leukocytes. Perioperatively, we investigated the relationship of IL-6 concentrations in the serum with lipopolysaccharide (LPS)-stimulated cytokine production in the whole blood of patients undergoing elective major abdominal operations. In 50 patients, we found a transient increase of IL-6 concentrations in the serum. Six hours after skin incision, in vitro stimulated production of IL-6 and TNFalpha was diminished by 72% (P<0.05). A significant increase in cytokine production was observed three days postoperatively, however this was 63% below the preoperative values. Patients with high concentrations of circulating IL-6 showed a significantly lower stimulated IL-6 production than patients with low serum concentrations of IL-6. We conclude, that two opposing effects are associated with surgery: an activation leading to IL-6-release into the circulation, and a prolonged hyporesponsiveness of circulating leukocytes. These reactions are positively related.

Abdomen↗

PubMed1999

Secretion of IL-6, monocyte chemoattractant protein-1, macrophage inflammatory protein-1alpha, and TNFalpha by cultured intact human peritoneum.

The peritoneum is an important site of host defence. The mesothelial cells, lining the peritoneum, and the fibroblasts found in the layers below are potent sources of a variety of mediators. Furthermore, granulocytes, mast cells, and macrophages, either resident or attracted by inflammatory processes, are interspersed within the tissue. We investigated the production of mediators by samples of fresh human peritoneum. The method described here has the advantage that the cellular composition of the human peritoneum remains intact. Samples of peritoneum were excised at the beginning of elective abdominal operations in infection-free patients. The tissue was placed across the wells of a microtitre plate, fixed in place by the plate cover and incubated with culture medium with or without lipopolysaccharide (LPS) for up to 5 h. The accumulation of IL-6, monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1alpha (MIP-1alpha) and TNFalpha in culture supernatants was measured by ELISA. Production of MCP-1 and IL-6 occurred spontaneously during incubation and was enhanced by as much as 4-fold in the presence of different concentrations of LPS (0. 5-500 ng/ml) in a dose-dependent manner. MIP-1alpha and TNFalpha were detected in culture supernatants of LPS-stimulated samples with concentrations about 8 times as high as those of samples cultured with no such stimulus. The addition of IL-1beta resulted in an increase in the release of IL-6 and MCP-1, similar to that observed with LPS stimulation, but failed to increase the production of TNFalpha. MIP-1alpha production was only marginally enhanced by IL-1beta. In conclusion, our experimental system is suitable for the investigation of chemokine and cytokine production by the human peritoneum, with the aim of assessing aspects of local immunocompetence.

Cell Survival↗

PubMed1999

[Production of chemokines by the human peritoneum].

AIM OF THE STUDY: Peritonitis is characterised by a continued infiltration of the peritoneal cavity with leukocytes, attracted by chemotactic mediators. The aim of this study was to demonstrate the capacity of the human peritoneum to secrete chemokines and to show a therapeutic option by impairing the proinflammatory function of the peritoneum. METHODS: Peritoneum was obtained from 12 consenting patients undergoing abdominal surgery for noninflammatory diseases. After opening the peritoneal cavity a piece of the parietal peritoneum was excised and subsequently incubated with lipopolysaccharide (LPS, 50 ng/ml) +/- interleukin-10 (IL-10, 100 U/ml) for five hours in vitro. The culture supernatants were assayed for concentrations of interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1) and monocyte inflammatory protein-1 alpha (MIP-1 alpha) by using the ELISA. RESULTS: The cultured peritoneum secreted MCP-1 (mean (SEM): 3416 (659) pg/ml) and IL-8 (2946 (894) pg/ml). The presence of LPS resulted in a fourfold enhancement of this secretion (MCP-1: 13563 (1613), IL-8: 9854 (1305) pg/ml) and led to the production of MIP-1 alpha (1476 (240) pg/ml). The LPS-stimulated production of all of these chemokines was significantly diminished by the presence of IL-10. CONCLUSION: The reaction of the peritoneum to LPS indicates its proinflammatory function in the context of peritonitis caused by gram-negative bacteria. This inflammatory reaction might be diminished by application of IL-10.

Chemokine CCL2↗

PubMed1998

Biotransformation, excretion, and nephrotoxicity of the hexachlorobutadiene metabolite (E)-N-acetyl-S-(1,2,3,4, 4-pentachlorobutadienyl)-L-cysteine sulfoxide.

Hexachlorobuta-1,3-diene (HCBD) is nephrotoxic in rodents. Its toxicity is based upon a multistep bioactivation pathway. Conjugation with glutathione by glutathione S-transferases to form (E)-S-(1,2,3,4,4-pentachlorobutadienyl)-L-glutathione (PCBG), further processing to the corresponding cysteine S-conjugate, and finally processing to a reactive thioketene are thought to be responsible for the observed nephrotoxic effects. A novel metabolite, identified as (E)-N-acetyl-S-(1,2,3,4, 4-pentachlorobutadienyl)-L-cysteine sulfoxide (N-AcPCBC-SO), was described after administration of [14C]HCBD to male Wistar rats. This metabolite is formed by sulfoxidation of N-acetyl-S-(1,2,3,4, 4-pentachlorobutadienyl)-L-cysteine (N-AcPCBC) mediated by cytochrome P450 3A and has been found to be cytotoxic to proximal tubular cells in vitro without activation by beta-lyase. In rats, given HCBD in vivo, only one diastereomer of the sulfoxide is excreted; however, in rat hepatic microsomes two diastereomers, (R)- and (S)-N-AcPCBC-SO, are formed. This study focuses on the mechanisms responsible for this discrepancy and on a possible contribution of N-AcPCBC-SO to the nephrotoxicity of HCBD in vivo. (R,S)-N-AcPCBC-SO (1:1 mixture of both diastereomers) and N-acetyl-alpha-methyl-S-(1,2,3,4,4-pentachlorobutadienyl)-d, L-cysteine sulfoxide (alpha-Me-N-AcPCBC-SO) were administered iv to male and female Wistar rats (20, 40, and 80 micromol/kg of body weight). alpha-Me-N-AcPCBC-SO cannot be cleaved by cysteine conjugate beta-lyase even if alpha-Me-N-AcPCBC-SO is deacetylated by acylases. Excretion of gamma-glutamyltranspeptidase, protein, and glucose in the urine, indicative for kidney damage, and histopathological examination of the kidneys showed marked differences in the renal damage in male and female rats after application of N-AcPCBC-SO and alpha-Me-N-AcPCBC-SO. Necroses of the kidney tubules were only found in male, but not female, rats. Major sex-specific differences were observed in the elimination of sulfoxides; the (R)-isomer was excreted in a 5-10-fold excess to the (S)-isomer after application of (R,S)-N-AcPCBC-SO. After purification, both isomers were administered to male rats resulting in the urinary excretion of (R)-N-AcPCBC-SO after giving the (R)-isomer; treatment with (S)-N-AcPCBC-SO, however, revealed the formation of (S)-N-acetyl-S-(2-glycinylcystein-S-yl-1,3,4, 4-tetrachlorobutadienyl)-L-cysteine. The results show major sex-specific differences in the nephrotoxic potency of N-AcPCBC-SO and alpha-Me-N-AcPCBC-SO. However, both N-AcPCBC-SO and alpha-Me-N-AcPCBC-SO are nephrotoxic in males, suggesting the formation of a vinyl sulfoxide as an additional, beta-lyase-independent mechanism in HCBD-caused nephrotoxicity.

Animals↗

PubMed1998

Monocyte function before and after surgical trauma.

The monocyte/macrophage plays a key role in the network of immune reactions. Dependent on activation, it is able to produce various cytokines which act on other cells of the immune system in the sense of upregulation or downregulation. In addition, it presents antigens by the HLA-DR molecule as an initial trigger of an antigen-specific T-cell response. Monocyte function is affected by surgical disease and further affected by surgical trauma. We found the monocyte to be activated in a subgroup of patients before the operation, related to an increased rate of postoperative septic complications. After the operation, plasma concentrations of IL-6 and IL-10 were increased indicating the activation of an immune response. After surgery HLA-DR expression decreased as well as LPS-stimulated TNFalpha and IL-6 production, the latter indicating a hyporesponsiveness of peripheral blood cells (presumably monocytes) to further stimulation. On the other hand, continuously high plasma concentrations of activation markers like neopterin and IL-6 in the postoperative course were associated with complications and poor outcome. In postoperative septic shock monocytes may be almost areactive towards natural stimuli like bacteria and endotoxin, since IL-6 and TNFalpha production decreased to very low amounts. Adequate pre- and postoperative monocyte function is related to an uneventful postoperative course after major surgical operations. Surgical trauma affects monocyte function rendering it less reactive, which is a potential risk factor for postoperative septic complications.

Humans↗

PubMed1990

The midsagittal area of the corpus callosum and total neocortical volume differ in three inbred strains of mice.

Differences in the midsagittal area of the corpus callosum have been reported between human males and females, between handled and nonhandled rats, and both within and between various strains of mice. This measure has, in addition, been related to handedness in humans and "pawedness" in certain strains of mice. The present study investigated the between- and within-strain differences in three inbred strains of mice, two with autoimmune disorders and spontaneously occurring developmental neuropathology, in the midsagittal area of the corpus callosum, the total neocortical volume, and the asymmetry of the neocortex. These morphometric measures were obtained from coronally sectioned celloidin-embedded material from New Zealand Black (NZB/BINJ), BXSB/MpJ, and DBA/2J mouse strains. NZB mice had a total neocortical volume larger than that of either the BXSB or DBA strains, whereas the BSXB mice had a midsagittal area of the corpus callosum larger than that of either of the other two strains. In addition, there was a positive correlation between these two measures. There was no correlation between total neocortical asymmetry and midsagittal area of the corpus callosum in any of the three strains. Finally, there were no differences in any morphometric measure between animals with or without developmental neuropathology in any given strain.

Analysis of Variance↗

PubMed1989

The effect of developmental neuropathology on neocortical asymmetry in New Zealand black mice.

Cerebral asymmetry can be considered along two continua-one based on direction (i.e., left or right) and another based on magnitude (i.e., symmetrical or asymmetrical). The possibility exists that these continua operate independently (Collins, 1981). To examine this possibility, the brains of 21 New Zealand Black (NZB) mice with molecular layer neuronal ectopias and 19 NZB mice without ectopias were studied. In NZB mice without ectopias, the magnitude of cerebral cortical asymmetry was negatively correlated to total cerebral cortical volume, a finding previously reported in both humans (Galaburda, Corsiglia, Rosen and Sherman, 1987) and rats (Galaburda, Aboitiz, Rosen and Sherman, 1986). NZB mice with ectopias showed no such relationship. However, both groups of mice had a consistent rightward bias in the direction of neocortical asymmetry, replicating previous results in rodents (Diamond, Johnson and Ingham, 1975; Diamond, Dowling and Johnson, 1981; Kolb, Sutherland, Nonneman and Whishaw, 1982; Ward and Collins, 1985). This suggests that the mechanisms underlying the magnitude of cerebral cortical asymmetry differ from those underlying the direction of this asymmetry.

Animals↗