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Biomedical subjects

T Richter

Publications and source records attributed to T Richter.

At least 55 records · Page 3Linked to original sources
PubMed1999

Association of depressive symptoms during abstinence with the subjective high produced by cocaine.

OBJECTIVE: During early abstinence, many cocaine-dependent individuals experience symptoms such as anhedonia, craving, fatigue, insomnia, and dysphoria. While several studies have shown an association between depressive symptoms and negative treatment outcome, the reasons for this association are unclear. The authors conducted this study in order to determine the association between severity of depressive symptoms during early abstinence and subjective effects of experimentally administered cocaine. METHOD: Seventeen cocaine-dependent individuals achieved 5 days of abstinence in a hospital setting. Forty mg of cocaine was given intravenously on the fifth day of abstinence, and participants were asked to rate the subjective effects produced by the cocaine. The relationship between the subjective high produced by cocaine and the symptoms experienced during the 5 days of abstinence was evaluated. RESULTS: Individuals experiencing more intense depressive symptoms experienced a significantly greater high from the 40-mg cocaine infusion than individuals who did not. CONCLUSIONS: These data suggest that the severity of depressive symptoms experienced during initial abstinence is associated with the intensity of the subsequent high produced by cocaine. This finding could help explain why individuals who experience greater levels of depression-like symptoms during abstinence appear to be at greater risk for unsuccessful treatment outcome.

Adult↗
PubMed1998

Molecular evidence of bone marrow involvement in advanced case ot Tgammadelta lymphoma with secondary myelofibrosis.

We describe the case of a middle-aged man with long indolent course of generalized Tgammadelta lymphoma. The onset of secondary myelofibrosis made cytological monitoring of the bone marrow infiltrates impossible. As during progression of the disease splenectomy revealed typical histological features of a high-grade hepatosplenic Tgammadelta lymphoma, the low-grade bone infiltrate was considered a secondary lymphoma. The use of the polymerase chain reaction helped to detect a constant and identical monoclonal rearrangement pattern of the T-cell receptor gamma-chain gene in both bone marrow and splenic T-cell infiltrates. The notion of a secondary spread of malignant T-cells to the bone marrow was thereby confirmed despite striking cytological differences between bone marrow and splenic infiltrates. This is the first report of a diagnostic DNA-based molecular approach using fixed decalcified bone marrow. This method may provide a major tool when dealing with myelofibrosis, which normally hampers sampling of cytological specimens.

Adult↗
PubMed1998

[Toxoplasmosis retinochorioiditis, a therapy comparison between spiramycin and pyrimethamine/sulfadiazine].

BACKGROUND: The treatment of toxoplasma retinochoroiditis with spiramycin is an alternative to sulfadiazine and pyrimethamine. The treatment with sulfadiazine is associated with multiple side effects. Sulfadiazine is contraindicated during pregnancy and breastfeeding period. Spiramycin has less side effects and is recommended during pregnancy and breastfeeding period. The efficacy of spiramycin in treatment of toxoplasma retinochoroiditis is still a matter of controversy. PATIENTS AND METHODS: In a retrospective study, side effects and outcome of therapy in 44 patients with toxoplasma retinochoroiditis treated with sulfadiazine and pyrimethamine (n = 30) or spiramycin (n = 14) were compared. We assessed duration of therapy and healing, ophthalmoscopic findings and observed side effects. RESULTS: The mean healing time in the group of spiramycin was 63.83 days in comparison to 88 days for the group of patients treated with sulfadiazine/pyrimethamine. The frequency of side effects was lower in the group treated with spiramycin. CONCLUSION: In comparison to a combined application of sulfadiazine and pyrimethamine the treatment with spiramycin alone requires a shorter duration of therapy and healing period. Additionally, side effects and contraindications appear to be less frequent. In view of these findings, spiramycin therapy must be considered as a promising approach in the treatment of toxoplasma retinochoroiditis.

Adult↗
PubMed1998

Primary culture and transfection of epithelial cells of human small intestine.

BACKGROUND: So far, no techniques are available for primary culture and efficient transfection of human small-intestinal enterocytes, which would provide a valuable tool to investigate intestinal function. METHODS: Human small-intestinal biopsy specimens were treated with collagenase and dispase. Resulting crypt units were cultured for several days. Using the intestinal epithelial cell lines Caco-2 and HT-29, we established optimal conditions for transfection of a control plasmid, which were then applied to primary cultured cells. RESULTS: Cells growing out of crypt units formed monolayer-like sheets and proliferated for several days. Most of the cells could be stained with antibodies against epithelial markers. Among seven different transfection reagents tested, Lipofectamine was the most potent, with transfection efficiencies up to 25% for primary enterocytes. CONCLUSIONS: An easy technique was developed providing viable small-intestinal enterocytes that can be efficiently transfected.

Cell Division↗
PubMed1997

Topographic analysis of proliferative activity in carotid endarterectomy specimens by immunocytochemical detection of the cell cycle-related antigen Ki-67.

BACKGROUND: On the basis of contradictory results found in animal experiments and coronary atherectomy tissue, there is an ongoing debate about the significance of cellular proliferation in human atherosclerosis. In the present prospective study, the cell cycle-related antigen Ki-67 was detected for topographic determination of cell turnover in distinct regions of human carotid endarterectomy specimens harvested en bloc by surgical biopsy. METHODS AND RESULTS: After en bloc resection, serial sections of 26 consecutive carotid lesions were analyzed by histomorphological examination and immunohistochemistry. Thereby, 319 high-power fields were attributed to separate plaque regions defined as follows: distal boundary of the lesion with normal intima, plaque shoulder, core region, and diffuse intimal thickening. Endothelial cells, smooth muscle cells, T cells, and macrophages were identified by immunostaining of factor VIII-related protein, alpha-actin, CD68, and CD45R0. An overall proliferation index of 0.49+/-1.05% was yielded by positive anti-Ki-67 immunolabeling, predominantly in macrophage-rich areas characterized by high cell density (>1000 cells/mm2) as well as in reparative sites in the perimeter of atheroma, intramural thrombosis, plaque hemorrhage, and neovascularization (P<.01). Few or no signs of proliferation activity were found in normal intima, in areas of dense alpha-actin positivity, or adjacent media. As shown by double immunostaining, macrophages and unspecified mesenchymal cells represented the prevailing proliferating cell type. CONCLUSIONS: Our results suggest that proliferation in advanced human carotid lesions is confined to the intima and focally concentrated in central plaque regions negative for alpha-actin. Furthermore, it apparently occurs primarily as part of inflammatory processes and structural repair predominantly involving macrophages, as well as unspecific mesenchymal cells.

Aged↗
PubMed1997

New insights into lipid and fatty acid metabolism via stable isotopes.

UNLABELLED: Dynamic processes are of great interest in the study of lipid and fatty acid metabolism. Their in vivo investigation is now possible with the use of stable isotope tracers and the available sensitive analytical technology. We present some examples demonstrating the assessment of lipid oxidation as well as modulating factors by analysis of the tracer appearance in breath CO2 by isotope ratio mass spectrometry (IRMS). In a child with severe hypertriglycendaemia due to decreased cleavage of chylomicrons, medium-chain triglycerides were oxidised normally, whereas utilisation of long-chain triglycerides was severely disturbed. In another patient with primary carnitine deficiency, the beneficial effect of carnitine supplementation on fat oxidation could be demonstrated. In combination with gas chromatography, the high sensitivity of IRMS may be used for the detection of tracer materials in various plasma metabolites. In a pilot study, we applied C-13C labelled linoleic and alpha-linolenic acids to infants aged 2 weeks and 11 months, respectively. In these subjects, we could show a relative decrease of the conversion of these essential fatty acids to their longer chain polyunsaturated derivatives with age. The ability of term infants aged 19 days to convert linoleic into arachidonic acid was evaluated by using small natural differences in 13C abundance between different foods. Stable isotopes are also suitable for elucidation of new metabolic pathways. As an example, we could show in rats that linoleic and alpha-linolenic acids, which are usually considered to be essential substrates, can be synthesized endogenously from C16 precursors. CONCLUSION: IRMS is well suitable for the clinical investigation of lipid metabolism with stable isotopes in children. With different sample preparation devices, breath CO2 as well as specific plasma components can be analysed. While breath tests are already applied in clinical routing testing, GC-C-IRMS is a promising tool for research.

Animals↗
PubMed1997

Aortico-left ventricular tunnel: late reoperations.

Aortico-left ventricular tunnel is a rare congenital anomaly that presents as aortic regurgitation in infancy or childhood. Information on late results of surgery, especially with reoperations for progressive aortic regurgitation and recurrences are limited. The case histories of two patients with reoperations following correction of aortico-left ventricular tunnel are reported.

Adolescent↗
PubMed1997

Percutaneous endoscopic gastrostomy in children and adolescents.

BACKGROUND: Long-term nasogastric tube feeding is often associated with irritation of the hypopharynx or dislocation of the tube. These pitfalls may be circumvented by percutaneous endoscopic gastrostomy. Although frequently used in adults, there is limited experience with the procedure in children. METHODS: A series of 139 patients (aged 3 weeks to 36.5 years, mean age, 4.4 years; weight 3.1-60 kg, mean weight, 15 kg) underwent placement of a percutaneous endoscopic gastrostomy because of central dysphagia (n = 103); general dystrophy caused by chronic renal failure, congenital heart disease, neoplasms, or cystic fibrosis (n = 26); requirement for special diets (n = 7); malnutrition related to respiratory insufficiency (n = 2); and gastric volvulus (n = 1). RESULTS: The percutaneous endoscopic gastrostomy was placed either in the stomach (n = 122) or in the duodenum (n = 15). In two patients a direct percutaneous endoscopic jejunostomy was performed, because duodenal placement proved impossible. Percutaneous endoscopic gastrostomies were placed using intravenous sedation (midazolam, etomidate, or diazepam). None of the patients required general or inhalation anesthesia. We observed 19 complications including: dislocation of the duodenal part into the stomach (n = 5); inflammation at the insertion site (n = 3); perforation of the stomach (n = 2), which healed under conservative treatment; disconnection of the retention disk (n = 4); occlusion of the tube (n = 4), and chronic vomiting (n = 1). Mean lifetime of a percutaneous endoscopic gastrostomy was more than 1 year. CONCLUSIONS: Percutaneous endoscopic gastrostomy provides a major improvement for children requiring long-term tube feeding. High efficacy and low rates of complication suggest that percutaneous endoscopic gastrostomy should be considered more often, even in infants.

Adolescent↗
PubMed1996

The IgA subclass distributions of endomysium and gliadin antibodies in human sera are different.

Subclass distributions of total IgA, IgA gliadin antibodies and IgA endomysium antibodies were investigated in 26 sera of patients with coeliac disease or dermatitis herpetiformis by means of enzyme immunoassay and fluorescence microscopy. Eight-point-three percent of total IgA belonged to the IgA2 subclass. The fraction of IgA2 gliadin antibodies amounted to 30.6% of IgA gliadin antibodies and was significantly different from the proportion of total IgA2. The relative percentage of IgA2 endomysium antibodies was very close to that of total IgA2 in serum (6.2%) and significantly lower than that of IgA2 gliadin antibodies. The results suggest an intestinal origin of gliadin antibodies. Different subclass distribution of IgA endomysium antibodies may be due to extraintestinal production or to the different nature of the endomysium antigen eliciting a more prominent IgA1 response than gliadin.

Antibodies↗
PubMed1996

Regional and racial specificities in sorghum germplasm assessed with DNA markers.

Three different molecular marker technologies were used to determine the relatedness of 84 different lines of sorghum. Both racial characterization and geographical origin were found to be correlated with relatedness. In some cases, the region of origin was the more significant factor, where samples of different races from the same locality were more closely related than were samples of the same race from different localities. Wild sorghums were shown to have few novel alleles, suggesting that they would be poor sources of germplasm diversity. The results also indicated that Chinese sorghums are a narrow and distinctive group that is most closely related to race bicolor.

Base Sequence↗
PubMed1996

[Results of partial splenic resection and transposition to the lateral abdominal wall in portal hypertension in childhood].

Between 1977 and 1995, 19 children with portal hypertension (nine extrahepatic, ten intrahepatic) were treated by transpositioning the spleen into the left abdominal wall. Among the patients with intrahepatic portal hypertension three died. Two patients underwent secondary diminuition of the transposed spleen due to relapsed hypersplenism. In one of our first patients the transposed spleen atrophied after tangential resection. All surviving patients except one preserved hepatic function. The serum colloid osmotic pressure was stable. Plasma ammonia levels were normal. Serum immunoglobulins (IgG, IgM, IgA and IgG subclasses) and complement components (C3c, C4) were analyzed. After transposition patients had normal or slightly elevated values of these proteins compared with controls.

Abdominal Muscles↗
PubMed1995

[Glandular myxoma of the heart].

Light microscopic, immunohistochemical and ultrastructural studies were performed on a surgically removed left atrial myxoma containing glandular structures. Routine examination showed glandular lumina lined by cylindric epithelium in the characteristic myoxoid stroma, and the glands contained PAS positive mucin. The glandular structures demonstrated significant positivity for wide-spectrum-CK, EMA, and moderate positivity for CEA. Stromal cells were positive for vimentin, FVIII. Ag was present only in surface cells and blood vessels. Ultrastructurally the gland showed characteristics of mucin secreting epithelium. The authors briefly overview the currently existing theories about the histogenesis of myxomas.

Adult↗