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Biomedical subjects

J Schmidt

Publications and source records attributed to J Schmidt.

At least 163 records · Page 9Linked to original sources

Surface vs intramuscular laryngeal electromyography.

PURPOSE: To compare surface and intramuscular laryngeal electromyography (EMG) with adductor pollicis muscle EMG after 0.1 mgxkg(-1) cisatracurium. METHODS: This prospective study included ten patients undergoing surgery with risk of damage to the recurrent laryngeal nerve (RLN). The tracheas were intubated after fentanyl/propofol without the aid of muscle relaxation. A surface laryngeal electrode was attached to the tube and placed amidst the vocal cords; two straight needles were inserted endoscopically into the left lateral cricoarytenoid muscle. Single twitch stimulation of the left RLN (0.1 Hz) was performed transcutaneously; skin EMG of the left adductor pollicis muscle was performed at 0.1 Hz. After supramaximal stimulation for 10 min, 0.1 mgxkg(-1) cisatracurium was injected. Lag, onset time and peak effect were measured and compared. RESULTS: Good correlation (r = 0.9, 0.8, P < 0.005) and good comparability of the two methods of laryngeal EMG (mean difference and limits of agreement: 0 +/- 28 sec for lag time, -2 +/- 84 sec for onset time) was shown. The mean surface laryngeal lag and onset times were 67 +/- 22 sec and 198 +/- 72 sec, compared with the adductor pollicis muscle (98 +/- 30 sec and 242 +/- 59 sec) at P < 0.01. Peak effects at larynx (92 +/- 9%) and adductor pollicis muscle (95 +/- 3%) were similar. CONCLUSION: Surface laryngeal EMG is comparable to intramuscular laryngeal EMG to determine degree and onset of the neuromuscular blockade. Increasing muscle relaxation does not cause the surface electrode to lose contact with the vocal cords and therefore underestimate onset time and peak effect.

Aged↗

Reduction of fat embolic risks in total hip arthroplasty using cannulated awls and rasps for the preparation of the femoral canal.

Fat embolic phenomena during cemented and non-cemented total hip arthroplasty occur even during the preparation of the femoral canal. This should be avoided in order to reduce the rate of fat embolic syndrome. In the present prospective study we demonstrate the benefit of cannulated awls and rasps in the reduction of fat embolic phenomena by means of transoesophageal echocardiography and extended cardiopulmonary monitoring. Two groups of 5 patients each with identical surgical procedures were treated either with cannulated (group 1) or with closed (group 2) awls and rasps. In group 1 no macroemboli but three embolic showers grades 1 and 2 were seen. In contrast to these findings, three macroemboli and four embolic showers grades 1 and 3 were demonstrated in group 2. We recommend cannulated awls and rasps for the preparation of the femoral canal in cemented and non-cemented total hip arthroplasty. They are a simple and inexpensive aid to avoid fat embolic syndrome.

Arthroplasty, Replacement, Hip↗

[Intraoperative electromyographic recurrent laryngeal nerve identification as a routine measure].

In recent years, two methods of intraoperative monitoring of the laryngeal nerve have mostly been used: evoked electromyographic responses via endscopically applied needle electrodes inserted into the adducting laryngeal muscles, and non-invasive electrodes like special tubes with integrated electrodes or separately insertable electrodes like the postcricoid electrode or disposable electrodes attached to the tube, as used in this study. The incidence of recurrent nerve paresis or paralysis during the IRM period was 1/174 nerves (0.6%). The advantage of the IRM is the quick and certain identification of the nerve; intraoperative monitoring cannot replace a proper surgical technique. We conclude that the IRM, using a laryngeal surface electrode attached to the tube, is a safe and reliable method.

Adult↗

[The intra-arterial calcium stimulation test in site diagnosis for surgical therapy of insulinoma].

BACKGROUND: Approximately 10% of all insulinomas--the most common neuroendocrine pancreatic tumor--occur in multiple sites of the pancreas (e.g., multiple endocrine neoplasia type I) and rarely as islet cell hyperplasia. Malignant insulinomas appear in 10% to 15% of cases. For these special groups and for patients with a reoperation preoperative localization of the tumour is advisable. With current imaging technology, including computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography, and somatostatin receptor scintigraphy (SRS), localization of insulinomas is often inadequate. METHODS: In this study we report our results using intra-arterial calcium-stimulated venous blood sampling (ASVS) to localize and guide the management of insulinomas for patients with a reoperation because of recurrent insulinomas or persistent hyperinsulinism, for patients with malignant neoplasm and for patients with a previous abdominal operation. RESULTS: For all three cases the insulinomas were correctly localized by the ASVS in contrast to the preoperative imaging studies. CONCLUSIONS: Our experience and a review of the current literature demonstrate that ASVS is a highly accurate (sensitivity > 90%) and a safe method for preoperative localization of insulinomas. For patients with a reoperation ASVS is recommended and the extensive use of other costly preoperative methods should be avoided.

Adult↗

Plasmapheresis combined with continuous venovenous hemofiltration in surgical patients with sepsis.

OBJECTIVE: To examine the effect of continuous venovenous hemofiltration (CVVHF) combined with plasmapheresis (TPE) in critically ill surgical patients after treatment of the septic focus. DESIGN: Observational pilot study. SETTING: University teaching hospital intensive care unit. INTERVENTIONS: TPE and CVVHF were administered 24 h after surgical and/or interventional treatment of septic focus. Arterial blood pressure, cardiac output, and systemic vascular resistance values were monitored. We examined the effect of the combined extracorporeal detoxification on outcome related to age, morbidity, organic failure rate, and initial APACHE II score. MEASUREMENTS AND RESULTS: Forty-three patients with sepsis were treated; 19 received TPE in combination with CVVHF, and 24 did not receive extracorporeal therapy. Overall mortality was 44.2%. In the therapy group mortality was lower (42.1 vs. 45.8%), but the primary organic failure rate was higher. The relationship between mortality and age was similar in the two groups. There was also no difference between the groups in the course of scores on APACHE II, multiple-organ failure, and sepsis severity. Only patients with an initial APACHE II score of 21-25 had a significant reduction in mortality after combined extracorporeal detoxification. Mortality of 17% in TPE/CVVHF patients with single- (pulmonary) and double-organ failure (renal/pulmonary) was significantly lower (P < 0.0001) than in untreated patients. CONCLUSIONS: Reduction in mortality in single- and double-organ failure was as high as 28% in septic patients with combined extracorporeal detoxification. A prospective randomized trial in sepsis and double-organ failure should be projected.

APACHE↗

Intraoperative ultrasonography versus helical computed tomography and computed tomography with arterioportography in diagnosing colorectal liver metastases: lesion-by-lesion analysis.

Helical computed tomography with arterioportography (CTAP) and intraoperative sonography (IOUS) are both recognized to be extremely sensitive in the detection of liver metastases measuring <2 cm in diameter. As sensitivity and specificity values for both techniques differ significantly in the literature and in default of sufficient published data regarding this subject, a lesion-by-lesion analysis was considered necessary. Accuracy of IOUS was compared with helical computed tomography (CT) and portal-phase contrast enhancement (CTAP) in the preoperative detection of liver metastases from colorectal carcinoma projected as a prospective blinded study. Cost efficiency should be determined. Liver CTAP and IOUS were evaluated in 33 patients with colorectal carcinoma. Metastases were resected in 10 cases, and the remaining 23 patients were observed for follow-up with CT investigations every 3 months for a period of 1 year. CTAP and IOUS detected all 13 lesions measuring 5-10 mm (13/13). One metastasis measuring >10 mm was missed by IOUS. CTAP presented an ideal sensitivity of 100%, but specificity was as low as 68%. IOUS sensitivity was 98% and specificity was 95%. IOUS and CTAP are of comparable value regarding the detection of liver metastases <10 mm. Both techniques may be used if resections of synchronous or metachronous metastases are planned in order not to miss limiting small lesions and to prevent superfluous liver surgery. Helical CT scan with dynamic intravenous contrast enhancement is considered the most cost-effective preoperative staging method, although local staging may not be achieved because of insufficient intraabdominal survey.

Adult↗

[Vitreoretinal surgery in complicated retinal detachment in children and adolescents].

BACKGROUND: The purpose of this study was to evaluate anatomical and functional results of vitreoretinal silicone oil surgery for complicated retinal detachments due to trauma and myopia in children and juveniles. METHODS: We retrospectively reviewed the records of children and juveniles up to 17 years of age who had undergone vitreoretinal surgery with silicone oil instillation for the above causes between 1990 and 1997. A total of 30 eyes of 29 patients were operated on, 24 because of trauma and the remaining 6 because of retinal detachment in high myopia. There was a mean postoperative follow-up period of 1.7 years. Silicone oil could be removed from 18 of the 30 eyes after a mean of 4.7 months. The median number of vitrectomies performed per eye was two (range one to five). RESULTS: In 21 of 30 eyes (70%) the retina could be reattached after one or more surgeries. Silicone oil was removed from 16 of these 21 eyes (53%) which was defined as anatomical success. Visual acuity increased (14 eyes, 48.3%) or remained unchanged (9 eyes, 31%) in 23 of 29 eyes (79.3%). Visual acuity decreased in 6 of 29 eyes (20.7%) despite surgery. Two eyes (6.7%) had to be enucleated due to bulbar phthisis. Seventeen eyes reached a postoperative visual acuity of at least counting fingers. In one child functional tests could not be performed due to young age. CONCLUSION: Vitreoretinal surgery with silicone oil endotamponade has become a standard procedure in treating complicated retinal pathologies in children and juveniles. In very young patients it is thought that silicone oil instillation has advantages over gas endotamponade since it is very difficult for children to keep the proper face-down positioning after the procedure. The retinal reattachment rate is encouraging. In the majority of cases visual acuity greater than or equal to counting fingers and thus orienting vision was reached postoperatively. In few cases even reading vision was regained.

Adolescent↗

Endothelin-1 induces interleukin-6 release via activation of the transcription factor NF-kappaB in human vascular smooth muscle cells.

The potent vasoconstrictor peptide endothelin-1 (ET-1) has been implicated in the pathophysiology of atherosclerosis and its complications. Since inflammation of the vessel wall is a hallmark of atherosclerosis, the purpose of the present study was to investigate the influence of ET-1 on cytokine production in human vascular smooth muscle cells (SMC) as a marker of inflammatory cell activation. ET-1 (100 pM - 1 microM) stimulated interleukin-6 (IL-6) secretion from human vascular SMC in a concentration-dependent manner. The ET-A-receptor antagonist BQ-123 (10 microM), but not the ET-B-receptor antagonist BQ-788, inhibited IL-6 release. ET-1 also transiently increased IL-6 mRNA compatible with regulation of IL-6 release at the pretranslational level. Electrophoretic mobility shift assays demonstrated time- and concentration-dependent activation of the proinflammatory transcription factor nuclear factor-kappaB (NF-kappaB) in ET-1-stimulated human vascular SMC. A decoy oligodeoxynucleotide bearing the NF-kappaB binding site inhibited ET-1-stimulated IL-6 release to a great extent suggesting that this transcription factor plays a key role for cytokine production elicited by ET-1. Moreover, the antioxidant pyrrolidine dithiocarbamate (10 microM) inhibited ET-1-induced IL-6 release indicating involvement of reactive oxygen species in ET-1 signaling. ET-1-stimulated IL-6 secretion was also suppressed by diphenylene iodonium (40 microM), an inhibitor of flavon-containing enzymes such as NADH/NADPH oxidase. The results demonstrate the ability of ET-1 to induce an inflammatory response in human vascular SMC. These observations may contribute to a better understanding of the role of ET-1 in inflammatory activation of the vessel wall during atherogenesis.

Antioxidants↗

Spectroscopy of individual light-harvesting 2 complexes of Rhodopseudomonas acidophila: diagonal disorder, intercomplex heterogeneity, spectral diffusion, and energy transfer in the B800 band.

This paper reports a detailed spectroscopic study of the B800 absorption band of individual light-harvesting 2 (LH2) complexes of the photosynthetic purple bacterium Rhodopseudomonas acidophila at 1. 2 K. By applying single-molecule detection techniques to this system, details and properties can be revealed that remain obscured in conventional ensemble experiments. For instance, from fluorescence-excitation spectra of the individual complexes a more direct measure of the diagonal disorder could be obtained. Further spectral diffusion phenomena and homogeneous linewidths of individual bacteriochlorophyll a (BChl a) molecules are observed, revealing valuable information on excited-state dynamics. This work demonstrates that it is possible to obtain detailed spectral information on individual pigment-protein complexes, providing direct insight into their electronic structure and into the mechanisms underlying the highly efficient energy transfer processes in these systems.

Energy Transfer↗

Removal of UroLume endoprosthesis: experience of the North American Study Group for detrusor-sphincter dyssynergia application.

PURPOSE: We present the experience of the North American UroLume Multicenter Study Group with removal of the UroLume endoprosthesis. MATERIALS AND METHODS: A total of 160 neurologically impaired patients were enrolled in the North American UroLume Multicenter Study Group for detrusor external sphincter dyssynergia application. Analysis was performed in 2 groups of patients in which the device was removed during insertion and after implantation, respectively. RESULTS: Device retrieval was required during insertion in 21 patients (13%) mainly due to misplacement or migration in 17. Extraction was done with minimal complications and in all but 2 cases subsequent UroLume implantation was successful. Of 158 men with the device in place 31 (19.6%) required removal. In 34 procedures 44 devices were removed, mainly due to migration. Time from implantation to removal ranged from 4 days to 66 months (mean 22 months). The UroLume was removed en bloc in 20 cases and in parts or wire by wire in 19. The majority of patients had no or minimal complications after extraction. Only 2 patients had serious temporary complications, including bleeding and urethral injury, with no lasting consequences. No malignancy developed as a result of UroLume insertion. CONCLUSIONS: While there is a potential for urethral injury and bleeding, UroLume endoprosthesis removal is largely a simple procedure with minimal complications and consequences.

Humans↗

Secondary products in mycorrhizal roots of tobacco and tomato.

Colonization of the roots of various tobacco species and cultivars (Nicotiana glauca Grah., N. longiflora Cav., N. rustica L., N. tabacum L., N. tabacum L. cv. Samsun NN, N. sanderae hort. Sander ex Wats.) as well as tomato plants (Lycopersicon esculentum L. cv. Moneymaker) by the arbuscular mycorrhizal fungus Glomus intraradices Schenck and Smith resulted in the accumulation of several glycosylated C13 cyclohexenone derivatives. Eight derivatives were isolated from the mycorrhizal roots by preparative high performance liquid chromatography (HPLC) and spectroscopically identified (MS and NMR) as mono-, di- and triglucosides of 6-(9-hydroxybutyl)-1,1,5-trimethyl-4-cyclohexen-3-one and monoglucosides of 6-(9-hydroxybutyl)-1,5-dimethyl-4-cyclohexen-3-one-1-carboxylic acid and 6-(9-hydroxybutyl)-1,1-dimethyl-4-cyclohexen-3-one-5-carboxylic acid. In contrast to the induced cyclohexenone derivatives, accumulation of the coumarins scopoletin and its glucoside (scopolin) in roots of N. glauca Grah. and N. tabacum L. cv. Samsun NN, was markedly suppressed.

Chromatography, High Pressure Liquid↗

Betalains from Christmas cactus.

The presence of 14 betalain pigments have been detected by their characteristic spectral properties in flower petals of Christmas cactus (Schlumbergera x buckleyi). Along with the known vulgaxanthin I, betalamic acid, betanin and phyllocactin (6'-O-malonylbetanin), the structure of a new phyllocactin-derived betacyanin was elucidated by various spectroscopic techniques and carbohydrate analyses as betanidin 5-O-(2'-O-beta-D-apiofuranosyl-6'-O-malonyl)-beta-D-glucopyranosid e. Among the more complex betacyanins occurring in trace amounts, the presence of a new diacylated betacyanin ¿betanidin 5-O-[(5"-O-E-feruloyl)-2'-O-beta-D- apiofuranosyl-6'-O-malonyl)]-beta-D-glucopyranoside¿ has been ascertained. Furthermore, the accumulation of betalains during flower development and their pattern in different organs of the flower has been examined.

Betalains↗

A chlorinated amide and piperidine alkaloids from Aloe sabaea.

Phytochemical investigations of Aloe sabaea afforded a new chlorinated amide, N-4'-chlorobutylbutyramide, and the toxic piperidine alkaloids coniine, gamma-coniceine and the quarternary N,N-dimethylconiine. This is the first report of the occurrence of a chlorinated compound in the Aloeaceae family.

Alkaloids↗

Chalconoids from Fissistigma bracteolatum.

Phytochemical studies on the leaves of Fissistigma bracteolatum yielded besides the two known compounds 2-hydroxy-3,4,6-trimethoxychalcone (1) and 5,7,8-trimethoxyflav-3-ene (2), five new chalconoids 2-hydroxy-3,4,6-trimethoxychalcene (3), 2-hydroxy-3,4,6-trimethoxydihydrochalcone (4), 2'-hydroxy-3',4',6'-trimethoxydihydrochalcone (5), 2'-hydroxy-3',4',6'-trimethoxy-beta'-methoxychalcane (6) and 2'-hydroxy-3',4',6'-trimethoxy-beta'-ethoxychalcane (7). The structures of these compounds were determined by mass and NMR spectroscopic methods.

Chalcone↗

Influence of pyrrolidine dithiocarbamate on the inflammatory response in macrophages and mouse endotoxin shock.

To analyze the immunomodulatory effect of pyrrolidine dithiocarbamate (PDTC) on the endotoxin (LPS) stimulated inflammatory response, we measured the LPS-stimulated cytokine and NO production in murine peritoneal macrophages, J774A.1 cells and human whole blood in the presence of PDTC (60 microM). PDTC significantly inhibited the production of nitrite, IL-1beta and IL-6 in these cells. TNFalpha release was stimulated in murine cells, but suppressed in human whole blood. We further investigated the influence of PDTC on mortality and cytokine release in mouse endotoxin shock. PDTC was i.p. injected 30 min prior to the induction of endotoxin shock in female NMRI-mice and survival was significantly improved as compared to controls (48% vs 20%, n=25 per group). Plasma concentrations of TNFalpha were slightly augmented while IL-6 levels were decreased in PDTC-treated animals as compared to controls, however, without reaching significance. We conclude that PDTC is a potent immunomodulatory substance that modulates the inflammatory response in vitro and reduces mortality in mouse endotoxin shock. The pathophysiological mechanisms of the protective effect of PDTC in vivo, however, appears to be pluripotent, comprising both antioxidative properties and the inhibition of NF-kB.

Animals↗