Andreas Büttner

Single Nucleotide Polymorphism and Haplotype Analysis of a Novel Tryptophan Hydroxylase Isoform (TPH2) Gene in Suicide Victims

BACKGROUND Tryptophan hydroxylase, the rate-limiting enzyme in the biosynthesis of serotonin, represents a major candidate in numerous genetic association analyses of suicidal behavior; however, the results are so far inconclusive. Recently, a second tryptophan hydroxylase isoform (TPH2) was identified in mice, which was exclusively present in the brain. In a previous postmortem study of our own group, we could demonstrate that TPH2 is also expressed in the human brain but not in peripheral tissues. METHODS We performed single nucleotide polymorphisms, haplotypes, and linkage disequilibrium studies on 263 suicide victims and 266 healthy control subjects with 10 single nucleotide polymorphisms in the TPH2 gene. RESULTS Significant association was detected between one single nucleotide polymorphism (p = .004, global p = .01) and suicide. Additionally, haplotype analysis also produced support for association (p < .0001, global p = .0001). CONCLUSIONS This is the first report about an association between TPH2 gene polymorphisms and completed suicide. Our findings provide evidence for an involvement of genetic variants in the TPH2 gene in suicidal behavior. These results might open up new research strategies for the analysis of the observed disturbances in the serotonergic system in several other psychiatric disorders.

Sex determination and estimation of stature from the long bones of the arm

The determination of sex and the estimation of stature from bones play an important role in identifying unknown bodies, parts of bodies or skeletal remains. In medico-legal practice statements on the probable sex of a decomposed body or part of a body are often expected even during autopsy. The present study was, therefore, restricted to few easily accessible dimensions from bones which were prepared only by mechanically removing soft tissues, tendons and ligaments. The specimens came from the Anatomical Institutes in Munich and Cologne from the years 1994-1998 including a total of 143 individuals (64 males and 79 females). The mean age was 79 years (46-108), the mean body height 161cm (134-189). The following measurements were taken: maximum humeral length (mean: 33.4cm in males; 30.7cm in females), vertical humeral head diameter (mean: 5.0cm in males, 4.4cm in females), humeral epicondylar width (mean: 6.6cm in males; 5.8cm in females), maximum ulnar length (mean: 26.5cm in males, 23.8cm in females), proximal ulnar width (mean: 3.4cm in males, 2.9cm in females), distal ulnar width (mean: 2.2cm in males; 1.8cm in females), maximum radial length (mean: 24.6cm in males; 22.0cm in females), radial head diameter (mean: 2.6cm in males, 2.2cm in females) and distal radial width (mean: 3.6cm in males; 3.2cm in females). The differences between the means in males and females were significant (P<0.0005). A discriminant analysis was carried out with good results. A percentage of 94.93% of cases were correctly classified when all measures of the radius were applied jointly, followed by humerus (93.15%) and ulna (90.58%). Applied singly, the humeral head diameter allowed the best distinction (90.41% correctly grouped cases), followed by the radial length (89.13%), the radial head diameter (88.57%) and the humeral epicondylar width (88.49%). The linear regression analysis for quantifying the correlation between the bone lengths and the stature led to unsatifactory results with large 95%-confidence intervals for the coefficients and high standard errors of estimate.

The neuropathology of heroin abuse

A broad spectrum of neuropathologic changes are encountered in the brains of heroin abusers. The main findings are due to infections, either due to bacterial spread from bacterial endocarditis, mycoses, or from HIV-1 infection. Other complications include hypoxic-ischemic changes with cerebral edema, ischemic neuronal damage and neuronal loss, which are assumed to occur under conditions of prolonged heroin-induced respiratory depression, stroke due to, for example, thromboembolism, vasculitis, septic emboli, hypotension, and positional vascular compression. Myelopathy is believed to be the result of an isolated vascular accident within the spinal cord due to an as yet unknown mechanism. A distinct entity, spongiform leukoencephalopathy, has been described mainly after inhalation of pre-heated heroin. A lipophilic toxin-induced process was considered to be due to contaminants and to be induced or enhanced by cerebral hypoxia, but a definite toxin could not be identified. At the cellular level, abnormalities in signal transduction systems and changes of various receptor densities have been reported. The exact etiology of the different neuropathological alterations associated with heroin abuse is still unclear, but may also be related to additional substances used as adulterants.

Regional mRNA expression of a second tryptophan hydroxylase isoform in postmortem tissue samples of two human brains

Tryptophan hydroxylase (TPH) as rate limiting enzyme in the biosynthesis of serotonin plays a major role as candidate gene in several psychiatric disorders. Recently a second TPH isoform (TPH2) was identified in mice, which was exclusively expressed in the brain. We investigated whether the mRNA of the human homologue of this new TPH2 isoform is expressed in the human brain but not in peripheral tissues. The study was performed with postmortem specimen obtained from two subjects who died on cardiovascular failure. TPH2 mRNA levels were determined by quantitative real time RT-PCR. TPH2 mRNA was exclusively present in the human brains but not in the investigated peripheral tissues. Our finding may open up new research strategies for the analysis of the repeatedly observed disturbances in the serotonergic system in patients suffering from several psychiatric disorders.

Colloid cysts of the third ventricle with fatal outcome: a report of two cases and review of the literature

Abstract Two cases of sudden death due to colloid cysts of the third ventricle are presented with a review of the literature. In the first case, a 40-year-old woman suffered an acute onset of severe frontal headache after an intercontinental air flight. The next day, she was found comatous and died 7 h after admission to a hospital. In the second case, a 33-year-old man with a medical history of recurrent headaches was found dead in his car. Autopsy in both cases revealed a colloid cyst of the third ventricle and hydrocephalus involving the lateral ventricles.

Ganglioglioma of the Spinal Cord: Report of Two Rare Cases and Review of the Literature

OBJECTIVE AND IMPORTANCE The goal of this article is to present the clinical and histopathological features of two rare cases of ganglioglioma occurring in the cervicothoracic and thoracolumbar spinal cord. CLINICAL PRESENTATION A 4-year-old female patient presented with tetraparesis, whereas a 54-year-old woman showed paraparesis of both feet. INTERVENTION Both tumors could be removed totally by microsurgical techniques. Light microscopically, the tumors in both cases showed basically identical histological features and were diagnosed as benign gangliogliomas. Postoperatively, the two patients did not show improvement. Tumor recurrence was not noted at follow-up examinations within 11 and 24 months after surgery, respectively. CONCLUSION Ganglioglioma must be considered in the differential diagnosis of tumors affecting the spinal cord. In cases of suspected spinal ganglioglioma showing no sharp delineation from the surrounding tissue, a subtotal tumor removal should be considered to prevent severe neurological deficits.

The cross-sectional area of the cervical spinal canal in patients with cervical spondylotic myelopathy. Correlation of preoperative and postoperative area with clinical symptoms.

Study Design. Retrospective analysis of routine computed tomography investigations. Objective. To investigate whether the extent of clinical symptoms in patients undergoing surgery for cervical spinal myelopathy depends on the transsectional area of the cervical spinal canal. Methods. Forty‐five patients underwent surgery using different techniques to enlarge the width of the spinal canal. For clinical evaluation before and after surgery, a modified score of the Japanese Orthopedic Association was used (mean follow‐up period, 19.6 ± 9.1 months). The cross‐sectional area of the spinal canal in computed tomography scans (C4‐C6) was quantified 1 day before and 1 week after surgery using pixel‐dependent area calculation software for three different density ranges given in Hounsfield units. Results. After surgery, a significant enlargement of the cervical spinal canal of 78.2 ± 55.9% could be achieved. The Japanese Orthopedic Association score increased significantly by 3.7 ± 2.2 points from a median preoperative score of 10 to a score of 14 after surgery. Patients with a preoperative Japanese Orthopedic Association score ≥ 10 achieved a significantly better outcome after surgery. Conversely, no patient with a postoperative area larger than 1.6 cm2 achieved a score of less than 12 Japanese Orthopedic Association‐points. No significant linear correlation, however, was found between the postoperative transsectional area and the postoperative Japanese Orthopedic Association score of all patients. Conclusion. The preoperative clinical presentation of the patient was found to be the only prognostic hint for improvement after surgery. Preoperative area measurements of the spinal canal cannot be used as a prognostic tool for surgical outcome. Further, the postoperative measurements do not correlate with the clinical outcome. These data, however, which refer to C4 to C6, provide evidence that every surgical procedure to enlarge the cervical spinal canal should result in an area of 1.6 cm2 or more.

Alternative Splicing and Extensive RNA Editing of Human TPH2 Transcripts

Brain serotonin (5-HT) neurotransmission plays a key role in the regulation of mood and has been implicated in a variety of neuropsychiatric conditions. Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in the biosynthesis of 5-HT. Recently, we discovered a second TPH isoform (TPH2) in vertebrates, including man, which is predominantly expressed in brain, while the previously known TPH isoform (TPH1) is primarly a non-neuronal enzyme. Overwhelming evidence now points to TPH2 as a candidate gene for 5-HT-related psychiatric disorders. To assess the role of TPH2 gene variability in the etiology of psychiatric diseases we performed cDNA sequence analysis of TPH2 transcripts from human post mortem amygdala samples obtained from individuals with psychiatric disorders (drug abuse, schizophrenia, suicide) and controls. Here we show that TPH2 exists in two alternatively spliced variants in the coding region, denoted TPH2a and TPH2b. Moreover, we found evidence that the pre-mRNAs of both splice variants are dynamically RNA-edited in a mutually exclusive manner. Kinetic studies with cell lines expressing recombinant TPH2 variants revealed a higher activity of the novel TPH2B protein compared with the previously known TPH2A, whereas RNA editing was shown to inhibit the enzymatic activity of both TPH2 splice variants. Therefore, our results strongly suggest a complex fine-tuning of central nervous system 5-HT biosynthesis by TPH2 alternative splicing and RNA editing. Finally, we present molecular and large-scale linkage data evidencing that deregulated alternative splicing and RNA editing is involved in the etiology of psychiatric diseases, such as suicidal behaviour.

Vascular changes in the cerebral cortex in HIV-1 infection

Abstract In human immunodeficiency virus 1 (HIV-1)-infected patients, a hypoperfusion is seen by SPECT analyses in different brain regions but a specific pattern for the predominance of a specific brain region has not been found. The vessels of the cerebral cortex of the frontal, temporal, parietal, and occipital lobes of acquired immunodeficiency syndrome (AIDS) brains and control brains were analyzed by immunohistochemistry and lectin histochemistry. Immunohistochemistry was performed for collagen IV, laminin (basal lamina), and factor VIII (endothelial cell) and lectin histochemistry [Ricinus communis agglutinin (RCA-I), Ulex europaeus agglutinin (UEA-I), wheatgerm agglutinin (WGA) and soybean agglutinin (SBA)] was used to study changes of glycoproteins in the endothelial cell membrane. Vessels were counted in the gray and white matter, and their staining intensity for the different antibodies and lectins was rated using a three-point scale. Immunoreactivity for collagen IV was reduced in AIDS brains, which may be related to thinning of the basal lamina of cerebral vessels, as has previously been shown by electron microscopy. Lectin histochemistry with SBA, UEA-I and WGA indicated loss of glycoproteins in the membrane of endothelial cells. The data from the present study show morphological changes of the endothelial cells and of the basal lamina in the brain of individuals with AIDS, and might represent the morphological sequelae of a disturbed blood-brain barrier, or may account for the hypoperfusion seen in SPECT analyses.

DNA methylation analysis of the angiotensin converting enzyme (ACE) gene in major depression.

Background The angiotensin converting enzyme (ACE) has been repeatedly discussed as susceptibility factor for major depression (MD) and the bi-directional relation between MD and cardiovascular disorders (CVD). In this context, functional polymorphisms of the ACE gene have been linked to depression, to antidepressant treatment response, to ACE serum concentrations, as well as to hypertension, myocardial infarction and CVD risk markers. The mostly investigated ACE Ins/Del polymorphism accounts for ∼40%–50% of the ACE serum concentration variance, the remaining half is probably determined by other genetic, environmental or epigenetic factors, but these are poorly understood. Materials and Methods The main aim of the present study was the analysis of the DNA methylation pattern in the regulatory region of the ACE gene in peripheral leukocytes of 81 MD patients and 81 healthy controls. Results We detected intensive DNA methylation within a recently described, functional important region of the ACE gene promoter including hypermethylation in depressed patients (p = 0.008) and a significant inverse correlation between the ACE serum concentration and ACE promoter methylation frequency in the total sample (p = 0.02). Furthermore, a significant inverse correlation between the concentrations of the inflammatory CVD risk markers ICAM-1, E-selectin and P-selectin and the degree of ACE promoter methylation in MD patients could be demonstrated (p = 0.01 - 0.04). Conclusion The results of the present study suggest that aberrations in ACE promoter DNA methylation may be an underlying cause of MD and probably a common pathogenic factor for the bi-directional relationship between MD and cardiovascular disorders.