Treatment of Parkinson's with L-DOPA. The early discovery phase, and a comment on current problems.
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Antiparkinson Agents↗
Biomedical subjects
A Carlsson
Publications and source records attributed to A Carlsson.
Tissue transglutaminase autoantibodies and human leucocyte antigen in Down's syndrome patients with coeliac disease.
UNLABELLED: The association between autoantibodies against tissue transglutaminase (tTG) and human leucocyte antigen (HLA)-DQB1 alleles was tested in Down's syndrome (DS) patients with and without coeliac disease (CD). Immunoglobulin A (IgA) and G (IgG) anti-tTG were measured in radioligand binding assays and compared with conventionally analysed IgA antibodies against gliadin (AGA) and IgA autoantibodies against endomysium (EMA) in 48 DS patients. HLA-DQB1 typing was carried out by polymerase chain reaction and hybridization with allele-specific probes in 41/48 patients. Both IgA-tTG and IgG-tTG, as well as EMA, were detected in 7/48 and AGA in 15/48 patients. Intestinal biopsy showed histopathological changes consistent with CD in 9/16 patients. HLA-DQB1 typing, available for 8/9 patients with and for 33/39 without CD, demonstrated that 5/8 with CD had DQB1*02 compared with 7/33 of those without (p = 0.0345). In patients with anti-tTG, 5/6 had the DQB1*02 allele compared with 7/35 of those without (p = 0.0053). CONCLUSIONS: Anti-tTG are HLA-DQB1*02-associated autoantibodies which together could be useful screening tests for silent CD in DS patients. In patients with gastrointestinal symptoms or clinical signs of malabsorption, anti-tTG should be combined with AGA to detect other forms of enteropathies and CD.
Adolescent↗
A prospective randomised trial of internal fixation versus arthroplasty for displaced fractures of the neck of the femur. Functional outcome for 450 patients at two years.
It remains a matter of debate whether displaced fractures of the neck of the femur should be treated by internal fixation or arthroplasty. We have compared the two methods with regard to complications, mortality and functional outcome. We studied 409 patients, aged 70 years and over, with subcapital fractures graded as Garden 3 or 4, in a two-year prospective multicentre study from 12 Swedish hospitals. They were randomised to internal fixation or arthroplasty. Patients who were mentally confused, bedridden or in a nursing-home were excluded from the survey. After two years the rate of failure was 43% in the internal fixation (IF) and 6% in the arthroplasty group (p < 0.001). In the IF group 36% had impaired walking and 6% had severe pain compared with 25% and 1.5%, respectively, in the arthroplasty group (both p < 0.05). There was no difference in mortality. With a high rate of failure and poor functional outcome after IF, we recommend primary arthroplasty for displaced fractures of the neck of the femur in patients over 70 years of age.
Aged↗
Partial dopamine agonists and dopaminergic stabilizers, in the treatment of psychosis.
The early demonstration of chlorpromazine efficacy in schizophrenia and its subsequent identification as a dopamine receptor antagonist, established the only known mechanism for antipsychotic development to date. By extension, it is easy to hypothesize that any mechanism shown to reduce dopamine-mediated transmission in brain will have antipsychotic properties. The evaluation of partial dopamine agonists for antipsychotic efficacy and their application in the treatment of psychosis has derived from this background. Partial dopamine agonists at the D2 dopamine receptor, have high affinity for that receptor, but reduced intrinsic activity. These agonists have higher affinity for the presynaptic autoreceptor than for the postsynaptic receptor. Hence, these compounds reduce dopamine synthesis and release through an agonist action at the dopamine autoreceptor. Moreover, the agonists have lower intrinsic activity at the postsynaptic receptor than its natural ligand dopamine. Therefore, they diminish the dopaminergic signal at postsynaptic sites as well through delivering a reduced message; this component of drug action becomes more prominent the lower the intrinsic activity of the drug. Several partial dopamine agonists have been evaluated in schizophrenia. One of them, aripiprazole, is nearing approval for marketing. With partial dopamine agonist treatment, advantages should accrue to schizophrenia treatment in the areas of affect control and cognitive performance.
Animals↗
Dopamine D(3) receptor antagonists. 1. Synthesis and structure-activity relationships of 5,6-dimethoxy-N-alkyl- and N-alkylaryl-substituted 2-aminoindans.
5,6-Dimethoxy-2-(N-dipropyl)-aminoindan (3, PNU-99194A) was found to be a selective dopamine D(3) receptor antagonist with potential antipsychotic properties in animal models. To investigate the effects of nitrogen substitution on structure-activity relationships, a series of 5,6-dimethoxy-N-alkyl- and N-alkylaryl-substituted 2-aminoindans were synthesized and evaluated in vitro for binding affinity and metabolic stability. The results indicate that substitution at the amine nitrogen of the 2-aminoindans is fairly limited to the di-N-propyl group in order to achieve selective D(3) antagonists. Thus, combinations of various alkyl groups were generally inactive at the D(3) receptor. Although substitution with an N-alkylaryl or N-alkylheteroaryl group yields compounds with potent D(3) binding affinity, the D(2) affinity is also enhanced, resulting in a less than 4-fold preference for the D(3) receptor site, and no improvements in metabolic stability were noted. A large-scale synthesis of the D(3) antagonist 3 has been developed that has proven to be reproducible with few purification steps. The improvements include the use of 3,4-dimethoxybenzaldehyde as a low-cost starting material to provide the desired 5,6-dimethoxy-1-indanone 5c in good overall yield (65%) and the formation of a soluble silyl oxime 17 that was reduced efficiently with BH(3).Me(2)S. The resulting amino alcohol was alkylated and then deoxygenated using a Lewis acid and Et(3)SiH to give the desired product 3 in good overall yield of ( approximately 65%) from the indanone 5c.
Animals↗
A paradigm shift in brain research.
As late as the 1950s, it was assumed that communication between nerve cells in the brain occurred predominantly, if not entirely, by electrical impulses. A decade later, the theory of chemical transmission, which until then had been thought to occur only in the peripheral nervous system, had gained strong entrance for the central nervous system. This paradigm shift opened up an enormous new perspective in brain research, not least by facilitating the study of brain function by means of chemical tools, which in different ways could modify the chemical signaling between nerve cells. Moreover, such tools sometimes turned out to be useful as therapeutic agents. Thus for the first time, a variety of disorders in the central nervous system could be treated effectively.
Animals↗
A half-century of neurotransmitter research: impact on neurology and psychiatry (Nobel lecture).
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History, 20th Century↗
A behavioural pattern analysis of hypoglutamatergic mice--effects of four different antipsychotic agents.
In a hypoglutamatergic rodent model, we have observed certain behaviours that might have relevance for the cognitive impairments seen in autism and schizophrenia. Thus, hypoglutamatergic mice show defective habituation, impaired attention, a meagre behavioural repertoire and a general behavioural primitivization. The aim of the present study was to characterise and quantify changes in movement pattern in mice rendered hypoglutamatergic by means of MK-801 treatment, using an automated video tracking system. Further, the effects of four different antipsychotic drugs, the classical neuroleptic haloperidol, the atypical antipsychotic clozapine, the DA D2/5-HT2A antagonist risperidone and the selective 5-HT2A-receptor antagonist M100907, were compared with respect to effects on NMDA antagonist-induced movement pattern alterations. We found that each receptor antagonist had a unique effect on the MK-801-induced behavioural primitivization. Haloperidol was unable to affect the monotonous behaviour induced by MK-801, while risperidone, clozapine and M100907 produced movement patterns of high intricacy.
Animals↗
A half-century of neurotransmitter research: impact on neurology and psychiatry. Nobel lecture.
The effect that research on dopamine and other neutro trasmitters has on disciplines like neurology and psychiatry is described.
Animals↗
Value of structured clinical and scintigraphic protocols in acute pulmonary embolism.
PURPOSE: To study the use of a combination of a clinical and scintigraphic protocol in relation to the final outcome diagnosis in patients with clinical suspicion of acute pulmonary embolism (PE). MATERIAL AND METHODS: A total of 170 patients with clinical suspicion of acute PE were all examined with ECG, blood chemistry, chest X-ray, pulmonary scintigraphy and selective pulmonary arteriography. The scintigraphic and clinical probabilities of PE were estimated on visual analogue scales (VASs) by different readers unaware of each others' results. The follow-up time was 6 months. In order to establish the final diagnosis a final outcome committee was created. They analysed in retrospect all the clinical and laboratory data and established whether the patient had had PE or not. RESULTS: The final outcome committee concluded that 53 patients had PE. When the scintigraphic and clinical probability judgements were congruent, a combined probability of 1-25% (i.e low probability) had a negative predictive value of 98%. When the combined probability was 26-75% (i.e. intermediate) half of the cases had PE. With a combined probability of 76-100% (i.e. high) the positive predictive value was 100%. CONCLUSION: By applying a model of combined clinical and scintigraphic probabilities for PE, the diagnosis is ruled in when the combined probability is high, and ruled out when the combined probability is low. However, nearly half of the patients will still have an uncertain diagnosis for which further diagnostic procedures may be allocated.
Adult↗
Interactions between monoamines, glutamate, and GABA in schizophrenia: new evidence.
In spite of its proven heuristic value, the dopamine hypothesis of schizophrenia is now yielding to a multifactorial view, in which the other monoamines as well as glutamate and GABA are included, with a focus on neurotransmitter interactions in complex neurocircuits. The primary lesion(s) in schizophrenia does not necessarily involve any of these neurotransmitters directly but could deal with a more general defect, such as a faulty connectivity of developmental origin. Nevertheless, a precise identification of neurotransmitter aberrations in schizophrenia will probably provide clues for a better understanding of the disease and for the development of new treatment and prevention strategies.
Animals↗
Modulation of amphetamine-induced striatal dopamine release by ketamine in humans: implications for schizophrenia.
BACKGROUND: Recent brain imaging studies have indicated that schizophrenia is associated with increased amphetamine-induced dopamine release in the striatum. It has long been hypothesized that dysregulation of subcortical dopamine systems in schizophrenia might result from a failure of the prefrontal cortex (PFC) to adequately control subcortical dopaminergic function. The activity of midbrain dopaminergic neurons is regulated, in part, by glutamatergic projections from the PFC acting via glutamatergic N-methyl-D-aspartate (NMDA) receptors. The goal of this study was to test the hypothesis that a pharmacologically induced disruption of NMDA transmission leads to an increase in amphetamine-induced dopamine release in humans. METHODS: In eight healthy volunteers, we compared striatal amphetamine-induced (0.25 mg/kg) dopamine release under control conditions and under sustained disruption of NMDA transmission induced by infusion of the noncompetitive NMDA antagonist ketamine (0.2 mg/kg intravenous bolus followed by 0.4 mg/kg/hour intravenous infusion for 4 hours). Amphetamine-induced dopamine release was determined with single photon emission computed tomography, as the reduction in the binding potential (BP) of the radiolabeled D(2) receptor antagonist [(123)I]IBZM. RESULTS: Ketamine significantly enhanced the amphetamine-induced decrease in [(123)I]IBZM BP, from -5.5% +/- 3.5% under control conditions to -12. 8% +/- 8.8% under ketamine pretreatment (repeated-measures analysis of variance, p =.023). CONCLUSIONS: The increase in amphetamine-induced dopamine release induced by ketamine (greater than twofold) was comparable in magnitude to the exaggerated response seen in patients with schizophrenia. These data are consistent with the hypothesis that the alteration of dopamine release revealed by amphetamine challenge in schizophrenia results from a disruption of glutamatergic neuronal systems regulating dopaminergic cell activity.
Adult↗
[Length of treatment in deep venous thrombosis--some comments].
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Anticoagulants↗
Inhibitory activity of the human papillomavirus type 1 AU-rich element correlates inversely with the levels of the elav-like HuR protein in the cell cytoplasm.
We have analysed the activity of the negative element in the late 3' untranslated region of the cutaneous human papillomavirus type 1 (HPV-1) mRNAs in a panel of epithelial cells, of both mucosal and cutaneous origin. The inhibitory activity was cell line dependent. Determination of the levels of heterogeneous ribonucleoprotein C1/C2 and HuR that have been shown previously to interact specifically with the HPV-1 negative RNA element revealed that low levels of the HuR protein in the cytoplasmic fraction correlated with high inhibitory activity of the HPV-1 element, whereas cell lines displaying low inhibitory activity contained high levels of HuR in the cytoplasm. These results suggested that the HuR protein has a positive effect on HPV-1 late gene expression.
3' Untranslated Regions↗
Network interactions in schizophrenia - therapeutic implications.
Research into the role of neurotransmitters and neural networks in the pathogenesis of schizophrenia has been remarkably successful in recent years. The hypothesis postulating a dopamine dysfunction, which has for a long time been supported only by indirect evidence, has received direct support by means of sophisticated imaging techniques. Interactions between dopamine and several other neurotransmitters in complex neural networks have been revealed, largely thanks to the advent of an array of new pharmacological probes. Two major pharmacological models of schizophrenia, based on hyperdopaminergia and hypoglutamatergia, respectively, are ready for clinical testing. In addition, the hypothesis of network stabilization as a major therapeutic strategy in psychiatry and neurology has now reached the 'proof-of-concept' level. From a therapeutic perspective, several ongoing and forthcoming clinical trials, using drugs acting on dopaminergic, serotonergic and glutamatergic receptors, give rise to optimism.
Animals↗
Modulated structure of Ag2SnO3 studied by high-resolution electron microscopy
The modulated structure of Ag2SnO3, disilver tin trioxide, was investigated by high-resolution electron microscopy and electron diffraction along four different directions. Electron diffraction showed an incommensurate one-dimensional modulated structure with a modulation wavevector of 1/6.4a*. High-resolution images showed a large number of superstructure domains with the size range 10-100 nm and orientations related by hexagonal rotation. The modulation was determined to be displacements along the c axis of the Ag atoms both in octahedral and linear coordination. An approximate structure model with a commensurate sixfold superstructure, with an orthorhombic cell (P2(1)2(1)2(1), a = 2.922, b = 1.267, c = 0.562 nm), is proposed. Calculated images and electron diffraction patterns, based on this model, agree well with experimental observations.
Journal Article↗
Polypeptide expression in prostate hyperplasia and prostate adenocarcinoma.
Cells were collected from prostate hyperplasias (n = 6) and prostate carcinomas (n = 6) and subjected to two-dimensional gel electrophoresis (2-DE). The resulting polypeptide patterns were analysed with the PDQUEST computer software. Malignant tumors showed significant increases in the level of expression of proliferating cell nuclear antigen (PCNA), calreticulin, HSP 90 and pHSP 60, oncoprotein 18(v), elongation factor 2, glutathione-S-transferase pi (GST-pi), superoxide dismutase and triose phosphate isomerase. In addition, decreases in the levels of tropomyosin-1 and 2 and cytokeratin 18 were observed in prostate carcinomas compared to prostate hyperplasias. This pattern of alterations is similar to that observed in other carcinomas in our previous studies. All malignant tumors showed simultaneous alterations in 5 or more of 9 markers studied, whereas only one case of benign hyperplasia showed alterations in 5 markers. The EST-data base for prostate tumors available from NCI (CGAP) was searched for the expression of the mRNAs corresponding to proteins identified in our gels. Large differences in the relative expression of mRNAs and proteins were observed. Our data show alterations in the pattem of polypeptide expression in prostate carcinomas which are similar to those observed in other carcinomas.
Adenocarcinoma↗
Insulin and glucagon secretion in patients with slowly progressing autoimmune diabetes (LADA).
To metabolically characterize patients with slowly progressing autoimmune diabetes (LADA) of short duration we measured insulin, C peptide, and glucagon responses to glucose and arginine at three blood glucose levels (fasting and 14 and 28 mmol/L) in 11 patients with LADA, 11 patients with type 2 diabetes, and 14 healthy control subjects matched for age and body mass index. The acute insulin response to arginine was impaired in LADA vs. type 2 diabetes at all glucose levels, with the greatest impairment in the maximally stimulated insulin concentrations (P<0.04). In contrast, beta-cell sensitivity to glucose was unaltered in LADA and type 2 diabetes. The glucagon concentrations were elevated in both LADA and type 2 diabetic patients compared with healthy control subjects (P<0.02), but did not differ between the diabetic groups. In conclusion, patients with LADA share insulin resistance with type 2 diabetic patients, but display a more severe defect in maximally stimulated beta-cell capacity than patients with type 2 diabetes.
Adult↗