Defining the role of T cell-derived leptin in the modulation of hepatic or intestinal inflammation in mice

The role of leptin in the immune system has been well established. While adipocytes represent the major source, leptin production by lymphocytes, infiltrating at the site of inflammation, was recently demonstrated. However, the significance of this locally released leptin remains unresolved. In the present study, two models in which absence of leptin-signalling is associated with protection were employed: the model of ConA-induced hepatitis and the CD4(+)CD45Rb(high) transfer model of colitis. For the ConA model, scid mice were reconstituted with either WT or leptin-deficient (ob/ob) CD4(+) T cells. Eight weeks post transfer, ConA was injected and serum ALT, TNFalpha, leptin as well as liver mononuclear cell activation and histological signs of inflammation were evaluated. No difference between recipients of WT or ob/ob cells was observed for any of the parameters evaluated. In the second model, either WT or ob/ob CD4(+)CD45Rb(high) cells were transferred into scid mice. No histological differences were detected, although recipients of ob/ob cells showed higher weight loss compared to recipients of WT cells. Spontaneous production of IL-6 from colon cultures obtained from recipients of ob/ob cells was reduced compared to recipients of WT cells, whereas stimulation of lamina propria lymphocytes with leptin resulted in a higher IFNgamma release in recipients of ob/ob cells compared to recipients of WT cells. In conclusion, the present study provides evidence that T cell-derived leptin does not play a major role in the regulation of the inflammatory process, indicating that the adipose tissue is the critical player in the immune-modulating effects of leptin.

DBH*444G/A polymorphism of the dopamine-β-hydroxylase gene is associated with alcoholism but not with severe alcohol withdrawal symptoms

As the enzyme dopamine-beta-hydroxylase (DbetaH) converts dopamine to norepinephrine and both transmitters seem to be involved in the pathology of alcoholism and severe alcohol withdrawal symptoms, the gene encoding DbetaH (DBH) was applied to explore the genetic background of alcoholism and severe withdrawal symptoms. 102 healthy control subjects and 208 alcoholics, including 97 patients with a history of mild withdrawal symptoms, 57 with a history of alcohol withdrawal seizure (AWS) and 82 with a history of delirium tremens (DT) were genotyped for the DBH*444G/A polymorphism revealing a significantly elevated frequency of genotypes carrying the A-allele (p = 0.02; after Bonferroni adjustment for multiple tests) in alcoholics compared to healthy controls. Frequencies of alleles and genotypes of individuals with mild withdrawal symptoms did not differ significantly from those of patients with DT or AWS.

Diminished production of proinflammatory cytokines in patients with Alzheimer's disease

Cerebral inflammation as well as systemic immunological alterations have been reported in Alzheimer's disease (AD). We examined the production of the proinflammatory cytokines interleukin-6, interleukin-12, interferon-gamma, and tumor necrosis factor-alpha in whole blood cell cultures of AD patients and age-matched controls. The production of all measured cytokines after mitogen stimulation is significantly decreased in the AD group compared to controls. The results reflect an attenuated secretory activity of monocytes/macrophages, but also of T-helper cells. The data sustain the assumption that a systemic, possibly age-related alteration of immune mechanisms may play a pathogenetic role in the development of AD.

A new quality-of-life measure for men experiencing involuntary childlessness

BACKGROUND

Infertility may considerably reduce quality-of-life. Many of the existing generic quality-of-life measures, which often focus on physical impairments, do not represent the specific complaints of infertile patients. In this article, we report on the development and validation of the TLMK (Tübinger Lebensqualitätsfragebogen für Männer mit Kinderwunsch), an instrument for measuring quality-of-life in male patients with involuntary childlessness.

METHODS

The first version of the questionnaire, which consisted of 91 items, was administered to 275 men who attended andrology and gynaecology clinics for fertility evaluations. After the questionnaires were scored, item analysis and reduction, principal component analysis and internal consistency analyses were conducted.

RESULTS

The final version of the TLMK consists of 35 items in four scales and provides an internally consistent quality-of-life profile for men experiencing involuntary childlessness. Convergent and discriminant validity was supported through the correlation of the TLMK scales with established questionnaires on life satisfaction (FLZ) and partnership (PFB).

CONCLUSION

The TLMK provides information about the quality-of-life in men experiencing involuntary childlessness and was found to be easy to administer and acceptable to patients. It may be used to assess patients' baseline and ongoing quality-of-life during fertility treatment and as an outcome variable in the evaluation of integrated psychological counselling.

Acute disseminated encephalomyelitis--a case series

Acute disseminated encephalomyelitis(ADEM) is an uncommon inflammatory demyelinating disease involving central nervous system white matter. A series of seven cases seen over a period of one year have been described. The patients presented with acute onset of focal neurological deficit (3 patients), alteration of sensorium(3) and ataxia(1). CT scan showed non specific hypodensity in 4 cases and was normal in 3 patients . MRI showed characteristic radiological changes. Complete recovery was seen in 3 patients , one died and 3 were left with sequelae.

Perfusion magnetic resonance imaging and magnetic resonance spectroscopy of cerebral gliomas showing imperceptible contrast enhancement on conventional magnetic resonance imaging

The purpose of the present paper was to evaluate the utility of perfusion MRI in cerebral gliomas showing imperceptible contrast enhancement on conventional MRI, and to evaluate the relationships of perfusion MRI and magnetic resonance (MR) spectroscopic results in these tumours. Twenty-two patients with histopathologically proven cerebral gliomas and showing insignificant contrast enhancement on conventional MR were included in the present study. All patients underwent perfusion MRI and MR spectroscopy on a 1.5-T MR system. Significant differences of the relative cerebral blood volume (rCBV) values and the choline : creatine ratios were noted between low-grade and anaplastic gliomas (P < 0.01). Good correlation was found between the rCBV values and the choline : creatine values (y = 0. 532x + 1.5643; r = 0.67). Perfusion MRI can be a useful tool in assessing the histopathological grade of non-contrast-enhancing cerebral gliomas. Along with MR spectroscopic imaging it can serve as an important technique for preoperative characterization of such gliomas, so that accurate targeting by stereotactic biopsies is possible.

Atypical diffusion-weighted magnetic resonance findings in glioblastoma multiforme

The present report describes two patients with glioblastoma multiforme with the tumour demonstrating low central apparent diffusion coefficient values similar to those found in cerebral abscesses. Although conventional MR images were fairly specific for tumour, the cases illustrate the need for exercising caution when using diffusion-weighted (DW) MR images for the differentiation of necrotic brain tumours from abscesses. The DW MR imaging information should always be integrated with the conventional spin-echo MR images.

Die Stellung von Leptin im Immunsystem - Verbindung von Endokrinologie und Immunologie

Leptin is primarily known as a hormone regulating food intake and the adjustment to a distinct state of nutrition. In the present work a new function of leptin will be described, namely the role of leptin in the immune system. Structural characteristics of leptin and the leptin receptor already suggest an immune modulatory function. The effect of leptin on the various populations of immune cells in vitro will be described. These data are supported by findings obtained in in vivo animal models as well as descriptive and functional data from leptin-deficient humans which will be outlined in detail. In conclusion, the chimeric function of leptin as hormone and a cytokine/adipokine represents a unique link between the immune and the endocrine system thus opening a new field of research and therapeutic options.

Diffusion-weighted magnetic resonance imaging and magnetic resonance spectroscopy in the evaluation of focal cerebral tubercular lesions

PURPOSE

To review magnetic resonance (MR) diffusion-weighted imaging (DWI) and spectroscopy findings in patients with focal cerebral tuberculosis and to assess whether these techniques can adequately characterize focal cerebral tubercular lesions.

MATERIAL AND METHODS

Sixteen patients with single or multiple lesions were evaluated on a 1.5T MR system. DWI was performed with three 'b' values of 50, 500, and 1000 s/mm2 and the apparent diffusion coefficient maps were calculated. MR spectroscopy was performed using the point-resolved single-voxel technique with 2 echo time values of 135 ms and 270 ms. The signal intensities of the tubercular lesions on diffusion images and the apparent diffusion coefficients (ADCs) of their centers, along with MR spectroscopy findings, were analyzed in relation to their T2-weighted MR appearances.

RESULTS

DWI identified 17 of the 20 lesions evaluated. Increased signal intensity was seen in 9 of the 17 lesions. The ADCs of the lesions ranged from 0.406 to 2.64 x 10(-3) mm2/s (mean +/- SD: 1.038 +/- 0.609 mm2/s). Most of the lesions with hyperintense centers on T2-weighted images were of increased intensity on diffusion images, while those with hypointense centers on T2-weighted images were of decreased signal intensity on diffusion images. However, no statistical difference in the ADCs was found between lesions with increased and those with decreased signal intensity centers on T2-weighted images. MR spectroscopy revealed a lipid peak at 0.9-1.3 ppm in all of the 14 lesions evaluated. An increase in normalized choline:creatine ratio was found in all the lesions in which the spectra were obtained with the voxel, including a variable portion of the lesion wall.

CONCLUSION

DWI and MR spectroscopy help in determining the nature of cerebral tubercular lesions; however, since the findings are varied, they do not help in specific characterization.

Development of intestinal inflammation in double IL-10- and leptin-deficient mice

Leptin-deficient (ob/ob) mice are resistant in different models of autoimmunity and inflammation, suggesting that leptin regulates immunity and inflammation. To investigate whether leptin deficiency modulates the spontaneous intestinal inflammation observed in interleukin (IL)-10-deficient mice, double IL-10- and leptin-deficient [IL-10 knockout (KO) ob/ob] mice were generated and compared with single IL-10 KO mice for colitis severity. Body weight in IL-10 KO ob/ob mice was significantly reduced compared with that of ob/ob mice. However, when compared with wild-type or IL-10 KO mice, IL-10 KO ob/ob mice were still markedly obese. IL-10 KO and IL-10 KO ob/ob mice developed colitis with a comparable time-course and severity in terms of macroscopic and histologic scores. Likewise, production of interferon-gamma, IL-6, and IL-13 from colon cultures and splenocytes did not differ among these two groups. Conversely, rates of apoptosis were higher in lamina propria lymphocytes obtained from the colon of IL-10 KO ob/ob compared with IL-10 KO mice. In conclusion, although leptin deficiency has been associated with resistance in models of autoimmunity and inflammation induced by exogenous stimuli, leptin appears not to play a significant role in the spontaneous colitis of IL-10 KO mice, although it modulates survival of intestinal lymphocytes.

Leptin receptor expression on T lymphocytes modulates chronic intestinal inflammation in mice

BACKGROUND

Leptin regulates appetite through the long isoform of its receptor in the hypothalamus. Although leptin regulates immune responses, it is still unknown whether a direct effect of leptin on lymphocytes is required.

AIMS

To clarify whether expression of leptin receptors on T lymphocytes modulates intestinal inflammation in mice.

METHODS

The model of colitis induced by transfer of CD4(+)CD45RB(high) (RB(high)) cells into scid mice was used. Wild-type (WT) or leptin receptor deficient (db/db) RB(high) cells were transferred into scid mice and development of colitis evaluated.

RESULTS

Leptin receptors were expressed on both RB(high) and RB(low) cells. Intestinal lymphocytes of mice with colitis expressed high leptin levels compared with healthy controls whereas the opposite was true for serum leptin levels. Transfer of RB(high) cells from db/db mice induced delayed disease compared with transfer of WT cells. A high rate of apoptosis in lamina propria lymphocytes and reduced cytokine production were observed early on in scid mice receiving db/db RB(high) cells. These effects were not due to the high levels of glucocorticoids present in db/db mice as administration of corticosterone to WT mice failed to reproduce this phenomenon. High expression of peroxisome proliferator activated receptor gamma was observed in the colon of recipients of db/db compared with WT cells. Freshly isolated db/db RB(high) cells produced low levels of interferon gamma. Despite delayed onset of colitis, as disease progressed differences between mice receiving WT or db/db cells were no longer apparent.

CONCLUSIONS

These results suggest that leptin affects the immune response, partly by acting on the long isoform of its receptor expressed on T lymphocytes.

Magnetic resonance evaluation of cerebral toxoplasmosis in patients with the acquired immunodeficiency syndrome

PURPOSE

To evaluate and delineate the characteristics of cerebral toxoplasmosis lesions using a combination of magnetic resonance (MR) spectroscopy, diffusion, and perfusion studies.

MATERIAL AND METHODS

A total of 8 patients with 23 lesions were evaluated on a 1.5-T MR system. Diffusion-weighted imaging (DWI) was performed with three 'b' values of 50, 500, and 1000 s/mm2, and the apparent diffusion coefficient maps were calculated. The diffusion-weighted appearances and the T2-weighted MR appearances of the lesions were compared. MR spectroscopy was performed using the point-resolved single-voxel technique with two TE values of 135 ms and 270 ms. Perfusion studies were carried out using the dynamic contrast-enhanced technique, and the relative cerebral blood volume maps were qualitatively and quantitatively analyzed.

RESULTS

DWI revealed the majority of the lesions as having increased diffusion within their necrotic centers, with the ADC ranging from 0.5 to 3.01 (mean +/- SD: 1.49 +/- 0.7). All the lesions revealed a predominant lipid peak on MR spectroscopy and were extremely hypovascular on perfusion MR studies.

CONCLUSION

MR diffusion, spectroscopy, and perfusion studies help in characterizing toxoplasmosis lesions and, in most cases, can be used in combination to help establish the diagnosis of toxoplasmosis.

Precursors of Borna disease virus-specific T cells in secondary lymphatic tissue of experimentally infected rats

Borna disease in rats represents an experimental model to study the immunopathological role of T cells in central nervous system disease. Adoptive transfer experiments were performed to investigate homing properties of T cells that infiltrate the brains of infected animals. Lymphocytes isolated from the brains of diseased rats were labelled with 5,6-carboxyfluorescein diacetate succinimidyl ester (CFSE) and transferred into immunosuppressed infected recipients. In recipient rats displaying neurological disease, labeled lymphocytes were demonstrated in the vicinity of brain cell lesions, suggesting that the neuronal destruction was dependent on the presence of transferred lymphocytes. Furthermore, the presence of virus-specific cytotoxic T cells was scrutinized in secondary lymphatic tissue and the functional activity of lymphocytes isolated from spleens, cervical lymph nodes, and mesenteric lymph nodes of infected animals was tested immediately after isolation and after in vitro restimulation. The data presented here indicate that precursors of Borna disease virus (BDV)-specific CD8(+) T cells are present and cytotoxic activity was demonstrated after in vitro cocultivation with infected cells in cervical lymph nodes and spleens but not in mesenteric lymphoid tissue. Adoptive transfer of in vitro restimulated T cells induced alterations in BDV-infected, immunosuppressed rats that resemble the well-defined clinical symptoms and neuropathology of Borna disease. This report provides for the first time formal evidence that virus-specific cytotoxic T cells are primed in the periphery after BDV infection, a disease that exclusively manifests itself in the central nervous system.

Relevance of liver enzyme elevations with four different neuroleptics: a retrospective review of 7,263 treatment courses

Data on liver enzyme elevations were collected in a retrospective study of 7,263 treatment courses with haloperidol, clozapine, perphenazine, and perazine. Charts of 233 patients hospitalized between 1980 and 1992 at Tübingen University Psychiatric Clinic were selected because clinically relevant increases of liver enzymes had been detected during monotherapy with one of the four examined neuroleptics. At least one hepatic enzyme (mostly alanine aminotransferase [ALAT]) exceeded the established reference range of 3-fold elevations of ALAT, aspartate aminotransferase, gamma-glutamyl transpeptidase, and glutamate dehydrogenase and 2-fold elevations of alkaline phosphatase (AP) during monotherapy with clozapine in 15%, perazine in 7.6%, perphenazine in 4%, and haloperidol in 2.4% of the cases. If all liver enzyme abnormalities with any elevation greater than the conventional upper limits are considered, incidences were as follows: clozapine, 78%; perphenazine, 62%; perazine, 59%; and haloperidol, 50%. Testing for overall differences within the four neuroleptics resulted in significantly different incidences of liver enzyme elevations (chi2 test,p < 0.0001). Threefold increases of AP (>540 U/L) were seen in three patients receiving haloperidol (0.3%) only. Twofold increases of AP (>360 U/L) were distributed as follows: clozapine, 1%; haloperidol, 0.8%; perazine, 0.3%; and perphenazine, 0.1%. Only in the group with 1-fold elevations of AP (>180 U/L) were the differences within the drug regimens significant (clozapine, 40.3%; haloperidol, 33.2%; perphenazine, 23.4%; and perazine, 23.1%; chi2 test, p < 0.0001). In the period under study, no instance of icterus occurred.

Both pain and EEG response to cold pressor stimulation occurs faster in fibromyalgia patients than in control subjects

Pain-evoked brain potentials elicited by laser stimulation have been repeatedly shown to be abnormal in fibromyalgia syndrome. However, to our knowledge this is the first study assessing enduring (cold pressor) pain and correlated EEG changes in fibromyalgia. EEG power and subjective pain ratings during the cold pressor test were analyzed and contrasted with tasks not involving sensory stimulation (rest, mental arithmetic and pain imagery) in 20 patients with fibromyalgia and 21 healthy control subjects. Fibromyalgia patients both perceived pain and judged pain as intolerable earlier than control subjects, while pain intensity ratings and EEG power changes during subjective awareness of pain were similar in both groups. In patients and control subjects, pain was correlated with a rise in delta, theta and beta power. EEG power spectra during pain imagery and mental arithmetic were significantly different from those observed during the cold pressor test. In conclusion, fibromyalgia patients seem to process painful stimuli abnormally in a quantitative sense, thus producing both the sensation of pain, as well as the associated EEG patterns, much earlier than control subjects. However, the quality of the pain-associated EEG changes seems similar.

The dopamine D2 receptor (DRD2) gene-a genetic risk factor in heavy smoking?

Indications of a genetic predisposition to nicotine dependence have been derived from numerous epidemiological data and from individual genetic studies suggesting the involvement of the dopaminergic D2 receptor. Previous association studies defined the TaqlA polymorphism as a risk factor for addiction, in particular for alcoholism and tobacco dependence. Results of investigations into this polymorphism in 110 severely addicted smokers and a control group of 60 population-matched German non-smokers did not support these findings. However, our results indicate an association between the DRD2-Fokl-1 allele and the onset and intensity of smoking.

Leiomyosarcoma of pancreas: imaging features

Leiomysosarcoma of the pancreas is rare. Radiological findings of four patients with this condition were reviewed. CT scan appearances were those of a predominantly homogenous, large, solid, enhancing mass with few areas of necrosis. A cystic appearance with thickened and nodular enhancing walls was seen in one case. A constellation of imaging findings including large size at presentation, greater vascular enhancement and absence of biliary dilatation should suggest leiomyosarcoma.