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Biomedical subjects

J Schmidt

Publications and source records attributed to J Schmidt.

At least 109 records · Page 6Linked to original sources
PubMed2001

[Opiate dependent pregnant patients and mothers. What must be regarded in drug substitution and detoxification].

Substitution treatment with methadone, is a major addition to the therapeutic options available to opiate-dependent patients. In the case of opiate-dependent pregnant women and mothers with children, however, it brings other problems with it. Thus, for example, cases of methadone poisoning of children have become known. In part these are accidental, but some are a result of deliberate attempts on the part of mothers to quieten their children. The present report from an outpatient addiction service describes specific possibilities for treatment, and offers of organized help for this group of patients.

Ambulatory Care↗
PubMed2001

HIV type 1 Nef promotes neoplastic transformation of immortalized neural cells.

To study the effects of HIV-1 Nef on CNS-derived cells in vivo, an expression system based on the murine neural stem cell line C17.2 was established. Stable expression of LAV-1(Bru)-nef in these cells induced a transformed phenotype and enhanced cell growth in soft agar. Further experiments using previously established nef-expressing human astrocytoma cell lines as well as nef-expressing murine fibroblasts suggested a brain cell-specific transforming activity of Nef. After implantation into syngeneic or nude mice both murine and human nef-expressing CNS-derived cells induced tumor development. Interestingly, human astrocytoma cells expressing a Nef mutant carrying a disrupted SH3-binding motif involved in protein-protein interactions failed to induce tumor formation. These in vivo data suggest that Nef promotes neoplastic transformation of immortalized murine neural stem cells and enhances malignancy of low-tumorigenic human astrocytoma cells. Nef may therefore be involved in the development of AIDS-associated brain tumors.

Animals↗
PubMed2001

Usefulness of the triple test score for palpable breast masses; discussion 1012-3.

HYPOTHESIS: The triple test score (TTS) is useful and accurate for evaluating palpable breast masses. DESIGN: Diagnostic test study. SETTING: University hospital multidisciplinary breast clinic. PATIENTS: Four hundred seventy-nine women with 484 palpable breast lesions evaluated by TTS from 1991 through July 2000. MAIN OUTCOME MEASURES: Physical examination, mammography, and fine-needle aspiration were each assigned a score of 1, 2, or 3 for benign, suspicious, or malignant results; the TTS is the sum of these scores. The TTS has a minimum score of 3 (concordant benign) and a maximum score of 9 (concordant malignant). The TTS was correlated with subsequent histopathologic analysis or follow-up. INTERVENTIONS: The TTS was prospectively calculated for each mass. Lesions with a TTS greater than or equal to 5 were excised for histologic confirmation, whereas lesions with scores less than or equal to 4 were either excised (n = 60) or followed clinically (n = 255). RESULTS: All lesions with TTS less than or equal to 4 were benign on clinical follow-up, including 8 for which the fine-needle aspiration was the suspicious component. Of the 60 biopsied lesions, 51 were normal breast tissue, 4 showed fibrocystic change, 1 was a papilloma, and 4 were atypical hyperplasia. All lesions with a TTS greater than or equal to 6 (n = 130) were confirmed to be malignant on biopsy. Thus, a TTS less than or equal to 4 has a specificity of 100% and a TTS greater than or equal to 6 has a sensitivity of 100%. Of the 39 lesions (8%) with scores of 5, 19 (49%) were malignant, and 20 (51%) were benign. CONCLUSIONS: The TTS reliably guides evaluation and treatment of palpable breast masses. Masses scoring 3 or 4 are always benign. Masses with scores greater than or equal to 6 are malignant and should be treated accordingly. Confirmatory biopsy is required only for the 8% of the masses that receive a TTS of 5.

Biopsy, Needle↗
PubMed2001

Artificial indoor streams as a method to investigate the impact of chemicals on lotic communities.

The potential hazard of chemicals on aquatic communities are generally evaluated by standardised single-species bioassays. Safety assessment is based on results gained from organisms adapted to lentic systems and biological interactions in ecosystems are neglected. While lotic communities are often at first in contact with chemicals, it is astonishing that microcosms with lentic communities are mainly used as a bridge between laboratory bioassays and outdoor aquatic systems. Hence, we established five artificial indoor streams to simulate abiotic factors of small rivers. The closed-circuit system was filled with nutrients added to tap water. Washed pebbles were used as sediment. The dynamics of a simple biocoenoses consisting of aufwuchs, Lumbriculus variegatus Asellus aquaticus and Gammarus fossarum was investigated. The dynamic of aufwuchs and periphyton was determined as dry weight and chlorophyll-a, respectively and qualitatively by pigment pattern. The abundance of different developmental stages of L. variegatus was determined at the end of the experiment as well as the population dynamics of G. fossarum and A. aquaticus. Survival rates of gammarids and juveniles per female were investigated and data were used for modelling the population dynamics. The experiment was carried out to investigate the performance of the established artificial streams and the developed approaches to investigate effects of chemicals on a basic lotic community. The prime reason to establish this approach was to close a gap between complex artificial stream systems and laboratory single species tests to assess the impact of chemicals on the aquatic environment.

Animals↗
PubMed2001

The lumbar paravertebral region provides a novel site to assess neuromuscular block at the diaphragm.

PURPOSE: We evaluated a novel, paravertebral site for assessment of neuromuscular block at the diaphragm. The neuromuscular blocking effect of 0.1 mg x kg(-1) cisatracurium at the adducting laryngeal muscles, the diaphragm and the adductor pollicis (AP) were compared. METHODS: In 24 patients undergoing thyroid surgery, evoked responses from the adducting laryngeal muscles and the AP muscle were obtained using surface electromyography (EMG). Skin electrodes were placed paravertebrally near T12/L1 or L1/L2 (novel position; n = 12) or conventionally (n = 12). After stimulation of the recurrent laryngeal, phrenic and ulnar nerves, the lag, onset time and maximum effect were measured (0.1 Hz, single twitch) as well as the time to reach 25% of T1/T0 (T 25%) using train-of-four stimulation every 20 sec. RESULTS: A mean maximum block of more than 94% was reached at all sites. Lag, onset time and T 25% at the adducting laryngeal muscles and the diaphragm were significantly (P <0.005) shorter than at the AP muscle and did not differ significantly between the two diaphragmatic monitoring sites (conventional: 64 +/- 21 sec, 166 +/- 41 sec and 20 +/- 3 min vs novel: 60 +/- 16 sec, 161 +/- 40 sec and 22 +/- 2 min respectively). CONCLUSION: Onset and duration of action of 0.1 mg x kg(-1) cisatracurium was shorter at the larynx and the diaphragm than at the AP muscle. EMG results obtained from the novel, paravertebral site did not differ from the conventional monitoring site at the seventh or eighth intercostal space and suggest this alternative site is appropriate for monitoring of the diaphragm.

Adult↗
PubMed2001

[Propofol-remifentanil versus sevoflurane-remifentanil for anesthesia for pediatric procedures in infants, children and adolescents].

INTRODUCTION: The aim of this study was to compare total intravenous anaesthesia (TIVA) using propofol and remifentanil (P/R-group) and balanced anaesthesia (BA) using sevoflurane and remifentanil (S/R-group) for paediatric surgery. PATIENTS AND METHODS: A total of 120 patients aged 6 months to 16 years scheduled for elective minor lower abdominal surgery were randomly assigned to receive either propofol (5-10 mg/kg/h) and remifentanil (0.125-1.0 microgram/kg/min) or sevoflurane (1.0-1.5 MAC) and remifentanil (0.125-1.0 microgram/kg/min). Perioperative haemodynamics as well as recovery and discharge times, PONV and side-effects were studied. The patients vigilance, comfort and pain intensity were assessed postoperatively using the objective pain discomfort scale, the Steward post-anaesthetic recovery score and a visual analogue scale. RESULTS: Postoperative recovery (9.0 vs 11.6 min) and extubation times (11.8 vs. 15.0 min) as well as the time taken until a Steward post-anaesthetic recovery score > 3/4 (15.2 vs. 21.4 min) was reached were significantly shorter in the P/R-group. However, the length of time until discharge to the ward, postoperative comfort, pain intensity and analgesic requirements as well as PONV were comparable in both groups. CONCLUSIONS: With regards to the investigated parameters, TIVA with propofol and remifentanil is equally effective as BA with sevoflurane and remifentanil in paediatric patients. However, considering the selected dosing regimen, recovery times were significantly shorter for children after TIVA.

Abdomen↗
PubMed2001

[Jejunum interposition as replacement of the pars descendens duodeni in extensive tubulovillous adenoma].

Reconstruction after partial duodenectomy with resection of the ampulla of Vater is often troublesome. We report the case of a 70-year-old patient with endoscopically non-resectable tubulo-villous adenoma of the descending duodenum including the ampulla of Vater in which subsequent biopsies revealed dysplastic areas. A partial resection of the descending duodenum including the ampulla of Vater was performed. Reconstruction was achieved by the interposition of a jejunal limb in which the ampulla could be reinserted to the posterior wall. The postoperative course was uneventful; a carcinoma was not found within the specimen. In cases of widespread adenomas of the ampulla of Vater, duodenum-preserving resection by interposition of a jejunal limb with reinsertion of the ampulla into the posterior wall may be used as an alternative to Roux-Y reconstruction and to Whipple's procedure.

Adenoma, Villous↗
PubMed2001

[Glucocorticosteroid therapy in optic neuritis and multiple sclerosis. Evidence from clinical studies and practical recommendations].

High-dose intravenous glucocorticosteroids (GS) are the treatment of choice for acute relapses in patients with multiple sclerosis. We review the evidence from published trials on GS treatment in MS. Several controlled clinical trials have proven the efficacy of high-dose GS in accelerating the recovery from acute attacks. With serial MRI recordings, a reduction in the number of enhancing lesions has been observed after high-dose GS treatment. Definitive long-term effects of GS on disease evolution could not been demonstrated. There is now evidence that ultra-high doses of GS might be superior in comparison to standard pulse treatment regarding relapse rate and disease progression. In experimental autoimmune encephalomyelitis (EAE), an animal model for some features of MS, doses of up to 50 mg/kg methylprednisolone markedly augmented T cell apoptosis in situ, leading to a faster clearance of inflammatory infiltrates. Apoptosis in peripheral blood leukocytes could also be detected after i.v. GS treatment in MS patients. In a recent MRI study, ultra-high doses of GS were significantly more effective in reducing contrast-enhancing lesions and in maintaining blood-brain barrier integrity after a clinical relapse. Further clinical trials are necessary to study the long-term effects of ultra-high doses of GS on disease progression and disability.

Animals↗
PubMed2001

Cement removal with an endoscopically controlled ballistically driven chiselling system. A new device for cement removal and preliminary clinical results.

In this paper, we introduce a newly developed miniaturised chiselling system (Swiss OrthoClast) which allows endoscopically controlled cement removal even from deep within the femur in hip revision arthroplasty. The intraoperative handling is demonstrated and illustrated. The device consists of a control unit, a handpiece, a set of chisels of different lengths, shape, and tip geometry, a set of plug extraction tools, and a special intrafemoral endoscope. It uses simple ballistic principles to effect fracturing of the bone cement. Inside the handpiece the projectile is accelerated and strikes the chisel head. The tip moves at high speed and with a small excursion towards the cement, which is fragmented mechanically by the movement of the chisel tip without generating heat. The device is being validated in a prospective, international, multicenter study, and we include here the results of the first 28 clinical procedures of cement removal. The duration of the procedure varied from 13 to 75 min, with an average of 32 min. In all but one case, the cement was completely removed. We noted one case of cortical fissuring.

Aged↗
PubMed2001

Skin only or silo closure in the critically ill patient with an open abdomen.

BACKGROUND: The morbidity and mortality of various open abdominal techniques remains unclear. METHODS: A retrospective review was made of all trauma or general surgery patients who underwent an open abdominal closure from January 1997 to December 2000, at a large urban acute care hospital. Data are mean +/- SD. RESULTS: From 1997 to 2000, 181 patients (aged 39.8 +/- 16.5 years) had an open abdomen for abdominal infection, planned reexploration, abdominal compartment syndrome, inability to reapproximate fascia, or as part of a "damage control" procedure. Twenty-three patients went on to develop an abdominal compartment syndrome. Gastrointestinal fistulas occurred in 26 patients, and 9 patients had a dehiscence. The overall mortality was 44.7%. Of the survivors, 52% went on to fascial closure, requiring 1 to 7 additional abdominal operations. CONCLUSIONS: The morbidity of the open abdomen varies with the particular indication. Gastrointestinal fistulas are the most common acute complication and an abdominal wall hernia, the most common chronic complication.

Abdomen↗
PubMed2001

Spectroscopy on the B850 band of individual light-harvesting 2 complexes of Rhodopseudomonas acidophila. I. Experiments and Monte Carlo simulations.

The electronic structure of the circular aggregate of 18 bacteriochlorophyll a (BChl a) molecules responsible for the B850 absorption band of the light-harvesting 2 (LH2) complex of the photosynthetic purple bacterium Rhodopseudomonas acidophila has been studied by measuring fluorescence-excitation spectra of individual complexes at 1.2 K. The spectra reveal several well-resolved bands that are obscured in the single, broad B850 band observed in conventional absorption measurements on bulk samples. They are interpreted consistently in terms of the exciton model for the circular aggregate of BChl a molecules. From the energy separation between the different exciton transitions a reliable value of the intermolecular interaction is obtained. The spectra of the individual complexes allow for a distinction between the intra- and the intercomplex disorder. In addition to the random disorder, a regular modulation of the interaction has to be assumed to account for all the features of the observed spectra. This modulation has a C(2) symmetry, which strongly suggests a structural deformation of the ring into an ellipse.

Bacterial Proteins↗
PubMed2001

Spectroscopy on the B850 band of individual light-harvesting 2 complexes of Rhodopseudomonas acidophila. II. Exciton states of an elliptically deformed ring aggregate.

Spectroscopy of individual light-harvesting 2 complexes from purple photosynthetic bacteria revealed a deformation of the circular complex into C(2) symmetry. The present work relates the geometry of the deformed aggregate to its spectroscopic properties. Different models of elliptical deformation are discussed and compared with the experimental findings. It is shown that the model with smaller interpigment distances, where the curvature of the ellipse is small, provides the best agreement with fluorescence excitation spectra of individual complexes.

Bacterial Proteins↗
PubMed2001

Formation and occurrence of dopamine-derived betacyanins.

In light of the fact that the main betaxanthin (miraxanthin V) and the major betacyanin (2-descarboxy-betanidin) in hairy root cultures of yellow beet (Beta vulgaris L.) are both dopamine-derived, the occurrence of similar structures for the minor betacyanins was also suggested. By HPLC comparison with the betacyanins obtained by dopamine administration to beet seedlings, enzymatic hydrolysis, LCMS and 1H NMR analyses, the minor betacyanins from hairy roots were identified as 2-descarboxy-betanin and its 6'-O-malonyl derivative. A short-term dopamine administration experiment with fodder beet seedlings revealed that the condensation step between 2-descarboxy-cyclo-Dopa and betalamic acid is the decisive reaction, followed by glucosylation and acylation. From these data a pathway for the biosynthesis of dopamine-derived betalains is proposed. Furthermore, the occurrence of these compounds in various cell and hairy root cultures as well as beet plants (Fodder and Garden Beet Group) is shown.

Betalains↗
PubMed2001

Furanocoumarins from Dorstenia gigas.

A series of linear and angular prenylated furanocoumarins and a benzofuran derivative were isolated from leaves and twigs of Dorstenia gigas (Moraceae), a plant occurring endemically on Socotra Island (Yemen). The structures were elucidated by spectroscopic methods (NMR, MS, UV) and chemical derivatization.

Benzofurans↗
PubMed2001

Patterns of phenylpropanoids in non-inoculated and potato virus Y-inoculated leaves of transgenic tobacco plants expressing yeast-derived invertase.

The patterns of secondary metabolites in leaves of yeast invertase-transgenic tobacco plants (Nicotiana tabacum L. cv. Samsun NN) were analyzed. Plants expressing cytosolic yeast-derived invertase (cytInv) or apoplastic (cell wall associated) yeast invertase (cwInv) showed a characteristic phytochemical phenotype compared to untransformed controls (wild-type plants). The level of phenylpropanoids decreased in the cytInv plants but increased in the cwInv plants, which showed an induced de novo synthesis of a caffeic acid amide, i.e. N-caffeoylputrescine. In addition, the level of the coumarin glucoside scopolin was markedly enhanced. Increased accumulation of scopolin in the cwInv plants is possibly correlated with the induction of defense reactions and the appearance of necrotic lesions similar to the hypersensitive response caused by avirulent pathogens. This is consistent with results from potato virus Y-infected plants. Whereas there was no additional increase in the coumarins in leaves following infection in cwInv plants, wild-type plants showed a slight increase and cytInc a marked increase.

Cell Wall↗
PubMed2001

Betalains of Celosia argentea.

The betalains of yellow, orange and red inflorescences of common cockscomb (Celosia argentea var. cristata) were compared and proved to be qualitatively identical to those of feathered amaranth (Celosia argentea var. plumosa). In addition to the known compounds amaranthin and betalamic acid, the structures of three yellow pigments were elucidated to be immonium conjugates of betalamic acid with dopamine, 3-methoxytyramine and (S)-tryptophan by various spectroscopic techniques and comparison to synthesized reference compounds; the latter two are new to plants. Among the betacyanins occurring in yellow inflorescences in trace amounts, the presence of 2-descarboxy-betanidin, a dopamine-derived betacyanin, has been ascertained. The detection of high dopamine concentration may be of toxicological relevance in use of yellow inflorescences as a vegetable and in traditional Chinese medicine, common uses for the red inflorescences of common cockscomb.

Amaranthaceae↗