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Biomedical subjects

G Friedrich

Publications and source records attributed to G Friedrich.

At least 55 records · Page 3Linked to original sources
PubMed1997

Cardiac troponin I to diagnose percutaneous transluminal coronary angioplasty-related myocardial injury.

The purposes of the present study were to evaluate cardiac troponin 1 (cTnl) in the diagnosis of percutaneous transluminal coronary angioplasty (PTCA)-related myocardial injury in comparison with cardiac troponin T (cTnT) and creatine kinase (CK) MB mass concentration, and to investigate the frequency of myocardial injury, as indicated by myocardial protein release, after clinically symptomless side-branch occlusion (SBO) which may occur in the proximity of the attempted stenosis. The final study population comprised 80 patients undergoing elective, single vessel PTCA. Blood samples were drawn before, 6, 24 and 48 h after PTCA. cTnI, cTnT and CKMB mass baseline values were within the reference intervals in all patients (cTnI < 0.1 microgram/l, cTnT < 0.2 microgram/l, CKMB < 5 micrograms/l). Two patients presented with primary failure of PTCA, and visually successful PTCA was performed in all remaining patients. Seven patients (four with SBO) subsequently developed acute myocardial infarction (AMI). Symptomless SBO occurred in 16 patients. In controls (n = 55) there were no significant increases in cTnI, cTnT, or CKMB concentrations compared with baseline values, and all markers stayed within their reference intervals. In half the patients with symptomless SBO (n = 8) all markers were slightly to moderately increased, in two additional patients only CKMB was elevated (cTnI: 0.1-1.0 microgram/l; cTnT: 0.25-0.81 microgram/l and CKMB: 7.9-25.6 micrograms/l). In the majority of patients with primary failure or AMI we found pronounced increases in all tested markers (cTnI: 0.2-12.0 micrograms/l; cTnT: 0.44-12.10 micrograms/l; CKMB: 19.2-423.0 micrograms/l). The results of this study indicate that cTnI is comparably useful to cTnT or CKMB mass for diagnosing myocardial injury in PTCA patients. From our results a preference for one of the tested parameters cannot be clearly derived. Post-procedural cTnI, cTnT, and CKMB mass values are not higher than baseline values in uncomplicated cases, whereas AMI after PTCA leads to pronounced marker increases. SBO, even when symptomless, leads frequently (in about half the patients) to slight marker increases.

Adult↗
PubMed1997

Surgical anatomy of the larynx.

Modern functionally oriented surgery of the larynx increasingly requires exact knowledge of the anatomy and landmarks of the endolaryngeal structures in relation to the laryngeal skeleton. Review of the literature reveals several opposing statements and controversial anatomical definitions regarding several clinically critical points. In order to obtain basic anatomical data morphological measurements were performed on a total of 50 laryngeal specimens. Measurements were taken on whole organs and on cuts in the horizontal and in the frontal plane, as well. The data were evaluated statistically, which resulted in the determination of average configurations and dimensions of cartilages and soft tissues of the larynx. In particular, the projection of the deeper structures on the surface and the distances and angles between the different structures were taken into consideration. In order to make these data clinically applicable a scale model has been developed that will allow a direct correlation and application for individual surgery.

Female↗
PubMed1997

Intestinal absorption of undegraded proteins in men: presence of bromelain in plasma after oral intake.

The human adult intestinal epithelium has traditionally been described as nonpermeable to proteins. However, indirect evidence suggests that reduced absorption of undegraded proteins might take place under physiological conditions. Using bromelain (an enzyme obtained from pineapple stems) as a model protein, we studied the extent of this mucosal permeation in 19 healthy men. The protein was detected in plasma by immunoassay and by its proteolytic activity after oral administration. The estimated plasma half-life was 6-9 h. After oral multidosing (3 g/day), plasma concentration reached as much as 5,000 pg/ml by 48 h. From the plasma concentration curve, it could be estimated that an average of 10.8 micrograms of bromelain was present in plasma in the 3- to 51-h period. The presence of undegraded bromelain in plasma was shown unequivocally by immunoprecipitation of plasma samples with antibromelain antibodies, followed by gel electrophoresis and immunodetection. Moreover, the enzyme retained its biological activity, at least in part. Circulating bromelain was found associated with alpha 2-macroglobulin and alpha 1-antichymotrypain. The results of this work confirm the existence of a small but significant intestinal transport of undegraded proteins in healthy men.

Administration, Oral↗
PubMed1997

Value of exfoliative cytology in differential diagnosis of epithelial hyperplastic lesions of the larynx.

In a comparative random study we examined material from suspicious laryngeal lesions from 85 patients. Material was obtained simultaneously by exfoliative cytology and biopsy. The diagnoses included keratosis, papilloma/papillomatosis, dysplasia/carcinoma in situ and invasive carcinoma. In each case we were able to demonstrate the cytological diagnostic criteria in the respective histological specimens. We illustrate this in the paper with some examples. Due to the excellent correlation between cytology and histology we are convinced that exfoliative laryngeal cytology is very significant in differential diagnosis of epithelial hyperplastic lesions.

Biopsy↗
PubMed1997

Renovascular arteriovenous differences in Lp[a] plasma concentrations suggest removal of Lp[a] from the renal circulation.

High plasma concentrations of lipoprotein[a] (Lp[a]) are considered a genetically determined risk factor for atherosclerosis. Lp[a] is produced by the liver. The site(s) and mechanism(s) of catabolism are presently unclear. Lp[a] is elevated secondary to end-stage renal disease which suggests a direct or indirect role of the kidney in the metabolism of Lp[a]. We therefore investigated, by a simple in vivo approach, whether Lp[a] is removed by the human kidney. Lp[a] plasma concentrations were measured simultaneously by various methods in the ascending aorta and renal vein of 100 patients undergoing coronary angiography or coronary angioplasty. Lp[a] levels differed significantly between the two vessels even after correcting for hemoconcentration (20.1 +/- 21.6 mg/dL versus 18.7 +/- 20.3 mg/dL, P < 0.001). This corresponds to a mean arteriovenous difference of -1.4 mg/ dL or -9% of the arterial concentration. No Lp[a] or intact apo[a] could be detected in urine from healthy probands. Although we cannot assign the kidney a regulatory role for Lp[a] plasma levels in humans with normal renal function, we conclude from our data that substantial amounts of this atherogenic lipoprotein are taken up by the kidney. The underlying mechanisms are unknown at the moment. This study therefore demonstrates for the first time that the human kidney plays an active role in the catabolism of Lp[a]. This may explain the elevated Lp[a] concentrations found in patients with chronic renal insufficiency.

Aged↗
PubMed1996

Usefulness of a new rapid bedside troponin T assay in patients with chest pain.

We evaluated the usefulness of a rapid, qualitative, bedside immunoassay for cardiac-specific troponin T in patients with chest pain. A concordant result between quantitative troponin T and qualitative troponin T assay was observed in 183 (96%) tests. The sensitivity of the rapid troponin T assay for detecting acute myocardial infarction increased significantly according to the number of hours elapsed after onset of chest pain from 17% for patients presenting within 4 h to 71% for patients presenting in the time interval of greater than 8 h from onset of chest pain (P < 0.001). Specificity ranged from 83 to 93% in the three time intervals evaluated. A concordant result between CK-MB-measurement and rapid troponin T assay was observed in 159 (83%) tests. In 14/191 tests a positive rapid troponin T and a negative CK-MB assay was observed. In 9/14 (64%) cases this result was true positive for the rapid troponin T assay and in 5/14 (36%) cases false negative. As sensitivity and specificity of the rapid troponin T assay are comparable with CK-MB measurements, rapid troponin T assay is a simple and useful laboratory tool for the bedside triage in patients with chest pain.

Adult↗
PubMed1996

Angiographically silent atherosclerosis detected by intravascular ultrasound in patients with familial hypercholesterolemia and familial combined hyperlipidemia: correlation with high density lipoproteins.

OBJECTIVES: This study sought to evaluate the extent of atherosclerosis in coronary and iliac arteries in patients with heterozygous familial hypercholesterolemia or familial combined hyperlipidemia, using intravascular ultrasound imaging. BACKGROUND: Intravascular ultrasound imaging provides cross-sectional tomographic views of the vessel wall and allows quantitative assessment of atherosclerosis. METHODS: Forty-eight nonsmoking, asymptomatic patients with heterozygous familial hypercholesterolemia or familial combined hyperlipidemia underwent intravascular ultrasound imaging of the left anterior descending coronary, left main coronary and common iliac arteries. Angiography showed only minimal or no narrowing in these vessels. Intravascular ultrasound images obtained during catheter pullback underwent morphometric analysis. Plaque burden was expressed as the mean and maximal intimal index (ratio of plaque area and area within the internal elastic lamina) and as the percent of vessel surface covered by plaque. RESULTS: Intravascular ultrasound detected plaque more frequently than angiography in the left anterior descending (80% vs. 29%, respectively), left main (44% vs. 16%) and iliac arteries (33% vs. 27%). Plaque burden was higher in the left anterior descending (mean intimal index [+/- SD] 0.25 +/- 0.16) than in the left main (0.11 +/- 0.16, p < 0.001) and iliac arteries (0.02 +/- 0.04, p < 0.001). Angiography detected lumen narrowing only in coronary arteries with a maximal intimal index > or = 0.42 (left anterior descending artery) and > or = 0.43 (left main artery). The area within the internal elastic lamina increased with plaque area in the left anterior descending (r = 0.82, p < 0.001) and left main arteries (r = 0.53, p < 0.001). By stepwise multiple regression analysis, the strongest predictor for plaque burden in the left anterior descending artery was the level of high density lipoprotein (HDL) cholesterol and total/HDL cholesterol ratio for the left main artery. CONCLUSIONS: In patients with heterozygous familial hypercholesterolemia and familial combined hyperlipidemia, extensive coronary plaque is present despite minimal or no angiographic changes. Compensatory vessel enlargement and diffuse involvement with eccentric plaque may account for the lack of angiographic changes. Levels of HDL cholesterol and total/HDL cholesterol ratio are far more powerful predictors of coronary plaque burden than are low density lipoprotein cholesterol levels in these patients with early, asymptomatic disease.

Adult↗
PubMed1996

Bilateral ventricular neurofibroma of the larynx.

Laryngeal neurofibroma (LNF) is an unusual tumour and only approximately two dozen cases have been reported previously. Isolated LNF not associated with von Recklinghausen's disease is even more unusual. According to a review of the available literature, the case presented is the first bilateral one and the first originating from the ventricles. The tumour was removed completely by microlaryngoscopy without tracheostomy. The macroscopic and light macroscopic findings are presented and a review of the literature on neurogenic tumours in the larynx is presented.

Humans↗
PubMed1995

Differentiation and maturation of rabbit retinal oligodendrocyte precursor cells in vitro.

The differentiation of oligodendrocytes from undifferentiated progenitor cells was studied in cultures obtained from the postnatal rabbit retina. 'Sandwich' cultures were established by turning the coverslips with adhering cells up-side down about 24 h after seeding. As a result O4-positive oligodendrocyte progenitors stop dividing and differentiate. Within 6 days in vitro they form extensive membranous sheets and acquire myelin associated glycoprotein (MAG), proteolipid protein (PLP), and myelin basic protein (MBP). O4-/MBP-positive oligodendrocytes and vimentin-positive/GFAP-negative Müller cells (a kind of modified astrocyte type in the retina), which are also present in these cultures, occupy distinct territories in vitro. When oligodendrocyte precursors were seeded onto a preformed Müller cell feeder layer they prefer to settle on the Müller cell free substrate poly-L-lysine, develop numerous processes but no membranous sheets and fail to acquire detectable amounts of MBP. In addition, culturing Müller cells and oligodendrocytes within the same medium, but without direct contact to each other, oligodendrocyte precursor cells fail to express MBP. The Müller cell factor(s) responsible for this interaction remains to be determined.

Animals↗
PubMed1995

[Basic principles for indications in phonosurgery].

BACKGROUND: Phonosurgery became an accepted surgical modality in the 1960s and refers to any surgery designed primarily for the improvement or restoration of voice. In a wider sense it also includes procedures involving the articulatory organs aiming at improvement of speech. Phonosurgery as "esthetic surgery" of the vocal organ differs clearly in its intentions from traditional laryngeal surgery which is performed because of vital indications. It is therefore necessary to define basic principles for the indication of phonosurgery. In this paper, general suggestions for the preconditions and importance of diagnostic criteria for the indication are given. PRECONDITIONS FOR INDICATION: 1. Diagnosis and documentation, 2. Patient's requests and needs, 3. Conservative therapeutic procedures or concept. RELEVANCE OF DIAGNOSTIC CRITERIA FOR INDICATION: 1. Audible findings, 2. Visible functional findings (stroboscopy), 3. Visible morphological findings. Phonosurgical interventions never should simply focus on the appearance of the vocal folds but on improving the patient's voice adapted to his or her individual requests and needs.

Articulation Disorders↗
PubMed1994

Lumen and plaque shape in atherosclerotic coronary arteries assessed by in vivo intracoronary ultrasound.

Current knowledge of lumen and plaque shape of atherosclerotic coronary vessels is derived from in vitro examination of coronary vessels. The in vivo plaque and lumen shape was studied by intracoronary ultrasound (ICUS) imaging in 82 patients with coronary artery disease and the images were analyzed by computerized morphometry. In 386 of the 638 cross sections (61%) with atherosclerotic plaque, nondiseased wall (intima thickness < 200 microns) was present in the ICUS image; in 440 sections (69%), the plaque was located eccentrically in the vessel. Although the extent of nondiseased wall segment and eccentricity decreased with plaque burden, 42% of cross sections with plaque stenosis > 60% had residual nondiseased wall, and 40% of these cross sections showed eccentric plaque. A circular or near-circular lumen (ratio of long/short diameter < 1.1) was found in 252 cross sections (39%), an elliptical lumen in 370 (58%), and a "D"-shaped lumen in 16 cross sections (3%); slit- or star-like lumen shapes were not detected. The ratio of long/short diameter was lower in the 555 noncalcified (1.10 +/- 0.08) than in the 83 calcified cross sections (1.15 +/- 0.08; p < 0.001). Radiographic lumen area measurements were simulated in ellipse models based on the long and short lumen axes measured in the ICUS images. Assuming a single radiographic view, maximal over- or underestimation of up to 40% compared with the true vessel lumen is possible. Errors in lumen area measurements increased with plaque area stenosis, reflecting the more elliptical lumen shape in advanced coronary disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1994

[Clinical use of alfentanil].

The fentanyl derivative alfentanil is a potent analgesic characterized by a quick onset time, short duration of action, low toxicity and short elimination time. Alfentanil is mainly used intraoperatively. In minor operations, its intravenous application is sufficient for anaesthesia. In major operations, the need for other anaesthetics can be reduced by the application of alfentanil. The best form of application is the computer-controlled infusion of alfentanil. The advantage of alfentanil over other opioids is the short recovery time of the patient. Alfentanil can also be used postoperatively for pain relief. Used intravenously after abdominal operations, it is approximately ten times more effective than morphine. Applied peridurally its analgesic effect corresponds approximately to that of morphine. Based on the lower amount of alfentanil needed, the patient-controlled application of alfentanil is superior to the use of constant infusion rates. In combination with midazolam, alfentanil can also be used for analgosedation of intensive care patients. Alfentanil is less useful for the treatment of cancer pain since it leads to greater development of tolerance than other opioids.

Adult↗
PubMed1993

[Functional structure of the human vocal cord].

19 laryngeal specimens (11 male, 8 female) were cut in horizontal serial sections, parallel to the free edge of the vocal cord. After staining, the structures of the glottis were measured microscopically and statistical analysis of the sex-related differences performed. The results show that the glottis can be divided not only into the well-known anterior and posterior glottis, but into five histological and functional distinctive portions. Within the anterior glottis, these parts are the freely vibrating midportion of the vocal cord, which is connected to the stiff laryngeal frame via an anterior and posterior transition zone. Within the posterior glottis there are two parts: the vocal process of the arytenoid cartilage (which is, according to Hirano, also the cartilage portion of the vocal cord) and the lateral wall of the posterior glottis. Statistical analysis of the data revealed significant sex differences, not only in the absolute measures but also on comparing the relative dimensions in respect of the total glottic length. The posterior glottis accounts for 37% of the total glottic length in men and for 42% in women and is therefore longer than generally accepted. We found statistically significant sex-related differences in the length of the posterior glottis, which is absolutely longer in men but relatively longer in women. The reason for this is the difference in the length of the midportion of the vocal cord. This zone is twice as long in men (8.5 mm) than in women (4.6 mm) and accounts for 37% of the total glottic length in men compared to 29% in women. As this portion is the most vibrating part of the vocal cord this could be an explanation for the unsolved phenomenon why the fundamental frequencies are 1:2 between men and women while all dimensions of the larynx are 1.5:1. The vibrating midportion of the vocal cord is connected to the stiff laryngeal framework by highly differentiated transition zones: the nodulus elasticus anterior and posterior. The lamina propria of the midportion shows a three-layered structure, orientated parallel to the free edge of the vocal cord. In the transition zones the deep layer of the lamina propria consists of interwoven bundles of collagen and elastic fibres, thus having the function of a "cushion ball" (Hirano). A functionally important portion is the vocal process of the arytenoid cartilage. The complex movements of the vocal process during abduction and adduction of the vocal cords produce a severe mechanical strain on the mucous membrane covering this part of the glottis.

Aged↗