Search PubMed⌕ Search

Biomedical subjects

T Vogt

Publications and source records attributed to T Vogt.

At least 127 records · Page 7Linked to original sources
PubMed1991

Prognostic significance of DNA cytometry in cutaneous malignant lymphomas.

The current classification of cutaneous malignant lymphomas (ML) into low-grade and high-grade lymphomas was found to be of limited reproducibility and permitted only a rough prediction about outcome. With this in mind, the relationship between nuclear DNA content and both prognosis and histologic grading according to the Kiel classification was evaluated on Feulgen-stained imprint specimens. In all, 49 cases of malignant non-Hodgkin's lymphoma, primary of the skin or with an involvement of the skin as one of the first symptoms, were studied using a computerized high-resolution image analysis system. The 2c deviation index (2cDI), which reflects the variation of the nuclear DNA values around the normal diploid peak, was found to be the best prognostically relevant criterion. Using the 2cDI, a significant discrimination (P less than 0.001 in the U test) between low-grade and high-grade ML was achieved. The prognostic benefit of the 2cDI was well documented by a significant inverse correlation between the 2cDI and the period of time until the patients progressed at least into one higher stage or died of lymphoma (r equals -0.63, P less than 0.05). In addition, the 2cDI enabled prognosis of the course of disease. In the group with low 2cDI values (2cDI, less than 0.5), no progression of the disease was observed after 1 year. In the groups presenting with a 2cDI between 0.5 and 1.0 and higher than 1.0, a progression was found in 57% and 64% of the cases studied, respectively. In conclusion, these measurements indicate that the determination of DNA distribution patterns in imprint specimens allows a precise and objective prognostic evaluation of cutaneous ML.

Adult↗
PubMed1991

Sequence changes in both flanking sequences of a pre-tRNA influence the cleavage specificity of RNase P.

The cleavage specificities of the RNase P holoenzymes from Escherichia coli and the yeast Schizosaccharomyces pombe and of the catalytic M1 RNA from E. coli were analyzed in 5'-processing experiments using a yeast serine pre-tRNA with mutations in both flanking sequences. The template DNAs were obtained by enzymatic reactions in vitro and transcribed with phage SP6 or T7 RNA polymerase. The various mutations did not alter the cleavage specificity of the yeast RNase P holoenzyme; cleavage always occurred predominantly at position G + 1, generating the typical seven base-pair acceptor stem. In contrast, the specificity of the prokaryotic RNase P activities, i.e. the catalytic M1 RNA and the RNase P holoenzyme from E. coli, was influenced by some of the mutated pre-tRNA substrates, which resulted in an unusual cleavage pattern, generating extended acceptor stems. The bases G - 1 and C + 73, forming the eighth base pair in these extended acceptor stems, were an important motif in promoting the unusual cleavage pattern. It was found only in some natural pre-tRNAs, including tRNA(SeCys) from E. coli, and tRNAs(His) from bacteria and chloroplasts. Also, the corresponding mature tRNAs in vivo contain an eight base pair acceptor stem. The presence of the CCA sequence at the 3' end of the tRNA moiety is known to enhance the cleavage efficiency with the catalytic M1 RNA. Surprisingly, the presence or absence of this sequence in two of our substrate mutants drastically altered the cleavage specificity of M1 RNA and of the E. coli holoenzyme, respectively. Possible reasons for the different cleavage specificities of the enzymes, the influence of sequence alterations and the importance of stacking forces in the acceptor stems are discussed.

Base Sequence↗
PubMed1991

High pancuronium sensitivity of axonal nicotinic-acetylcholine receptors in humans during organophosphate intoxication.

The effect of low-dose pancuronium on neuromuscular transmission was studied in 2 patients during the early and late stages of severe organophosphate intoxication. Single evoked compound muscle action potentials (CMAP) were followed by repetitive discharges and a decrement-increment (D-I) phenomenon with 10-, 20-, and 50-Hz supramaximal nerve stimulation. Intravenous pancuronium, 1 mg, abolished the D-I phenomenon, while the repetitive discharges of the CMAP were only partially reduced. It is postulated, that the disappearance of the D-I phenomenon with persistence of the CMAP repetitive discharges results from blockade of nicotinic-acetylcholine receptors located on the terminal axon responsible for stimulus-induced antidromic backfiring. This response to a very low dose of pancuronium indicates a high sensitivity of the axonal nicotinic-acetylcholine receptor to pancuronium in humans, as had been previously postulated from animal experiments.

Evoked Potentials↗
PubMed1990

Fasciculations due to verapamil in a patient with neuropathy.

A patient with pre-existing peripheral neuropathy developed generalized fasciculations under verapamil which ceased after discontinuation of the drug. It is suggested that the increase in acetylcholine (ACh) release at the neuromuscular junction by verapamil may trigger fasciculation in the state of regeneration at ACh-sensitive sites of axon terminals and immature axon sprouts.

Aged↗
PubMed1990

Alcohol-dependent unilateral vestibular impairment persisting after a closed head injury.

A 20-year-old man suffered a closed head injury followed by symptoms of right-sided labyrinthine concussion with complete clinical recovery within 3 weeks. Episodic vertigo and ataxic gait occurred after the ingestion of small amounts of alcohol over the next 2 years. Electro-oculography revealed a right-sided peripheral type vestibular lesion, only after taking alcohol. This was interpreted as an alcohol-induced impairment of central compensation following an incomplete recovery from right-sided labyrinthine trauma.

Adult↗
PubMed1990

Differentiation between lymphomas and pseudolymphomas of the skin by computerized DNA-image cytometry.

The histologic and immunohistologic differential diagnosis between pseudolymphomas (PL) and malignant lymphomas (ML) of the skin can be difficult. Since DNA cytometry has been found to be of both diagnostic and prognostic value in various neoplasms, its ability to discriminate between ML and PL in Feulgen-stained imprints of 17 PL and 49 ML skin biopsies was examined by high-resolution image analysis. The reliability of the following algorithms of DNA distribution was evaluated: 1) 2cDI (2c-deviation index), which reflects the variation of the nuclear DNA values around the diploid DNA peak; 2) percentage of cells having a DNA value greater than or equal to 5c (5cER; 5c-exceeding rate); 3) percentage of cells presenting with a DNA value greater than or equal to 4c (4cER). A 2cDI of 0.1 was found to be the most reliable marker for the differentiation between PL and ML. On the basis of this feature, 16 of 17 cases of PL and 46 of 49 cases of ML were correctly classified. The sensitivity, specificity, and efficiency of this feature were 94%. A 5cER greater than or equal to 1% had a specificity of 100%, but the sensitivity was only 43%. For the 4cER, a sensitivity of 61% and a specificity of 94% were found. In conclusion, the calculation of the 2cDI and the 5cER based on high-resolution image analysis provided additional helpful diagnostic features, and therefore should be included as a diagnostic tool. If the 5cER is at least 1%, the diagnosis of a ML can be confirmed with a specificity of 100%.

Cytophotometry↗
PubMed1990

Relationship between electrical and mechanical properties of motor units.

In six healthy volunteers, the size of the motor unit action potential (MUAP) was related to its contractile behaviour. Electrical activity was determined by measuring amplitude and area of the potential, using the macro electromyography (EMG) technique. The mechanical response was characterised by contraction time, twitch force and relaxation time, recorded with the spike triggered averaging technique. With increasing tension of the whole muscle corresponding to an increasing threshold, the force of single units enlarged exponentially compared to their EMG. There was only a weak relationship between contraction time and electrical activity and none between EMG and relaxation time.

Action Potentials↗
PubMed1990

Pancuronium improves the neuromuscular transmission defect of human organophosphate intoxication.

Two patients with acute severe organophosphate intoxication showed (1) single evoked compound muscle action potentials (CMAP) with repetitive discharges and (2) prominent decremental responses of CMAP with 20 and 50 Hz supramaximal nerve stimulation. Following the intravenous injection of single small doses of pancuronium, marked improvement in these abnormalities occurred and persisted for several hours. We postulate that the physiologic improvement following low-dose pancuronium results from blockade of acetylcholine receptors, especially those located on the terminal axon responsible for antidromic backfiring.

Action Potentials↗
PubMed1990

[Methodology and diagnostic potentialities of macro-EMG. I. Methodology].

Macro-EMG records electrical activity from the whole motor unit (MU) as a parameter of its size. The main component of the recording device is a modified single fiber or concentric needle electrode. Different sized uptake areas allow to record with different selectivities from the MU. The teflon insulated shaft surface allows to record with a defined large blank area unselectively macro-signals from the muscle. The conceptual ideas to use a concentric needle in addition to the single fibre electrode is to simplify the trigger-potential recording, which needs to be selective within the MU. In both instances the EMG apparatus has to provide two channels, one for the trigger and the second for an averaging device to record the macro-EMG. The different techniques use the single fiber or concentric EMG-potential as a trigger to average the associated macro-potential from the raw signals. The electrodes different design allow the whole single-fiber-needle to lie within the MU territory whereas the MU is only touched by the concentric needles tip. This implies different recording situations and results. Anatomically macro-EMG size is varied by the recording site of the muscle. The signal is greater close to the endplate zone and declines to stable values about 20 mm apart. For quantitative measurements within a muscle 20 different potentials have to be evaluated for median amplitude, duration and area.

Electromyography↗
PubMed1990

[Methodology and diagnostic possibilities of macro-EMG. II. Diagnostic possibilities].

The macro-EMG can be recorded with a modified single fiber or concentric needle. The two needles attain different results with smaller potentials values for the concentric needle type. For the single fiber type normal data are given for the EDC and tibialis anterior muscle. These data are compared with previously published results and their statistical evaluation. The concentric needle type can be used for scanning EMG. In addition potential stability can be examined in different parts of the MU using the unblanketing principle. A further novel use for macro-EMG is simultaneous single motor unit twitch recording to compare mechanical and electrical MU activity. In normal muscle the electrical signal is positively correlated with twitch force. In diseased muscle like ALS twitch is dissociated from electrical potential size. Macro-EMG allows to quantify MU size, a prerequisite to follow up dynamic changes in muscle. Improved computer programs in commercially available EMG-machines will help to introduce this method into clinical EMG laboratories as a useful addition to increase the diagnostic yield of EMG.

Electromyography↗
PubMed1988

[Study of the long-term effects of amiodarone on thyroid function using ultrasensitive TSH measurements. Preliminary report].

The results of a prospective study of basal ultrasensitive TSH concentrations in patients during long-term treatment over 12 months with amiodarone are reported. 2 patients (3%) developed hypothyroidism, whereas no case of hyperthyroidism was observed. A significant increase in FT4 with a simultaneous decrease in T3 was demonstrated at every periodic investigation during amiodarone therapy. In most patients ultrasensitive TSH values stayed within the normal range and showed no significant alteration during treatment. A slow decline in TSH during therapy was observed in a subgroup of patients with completely euthyroid initial TSH concentrations. This TSH decrease reached statistical significance after 12 months' therapy. FT4 showed pathological results in 35% of all determinations at any time during the study, T3 in 27%, and TSH in only 17%. In conclusion, a new steady-state of thyroid tests is attained during treatment with amiodarone and most patients maintain a euthyroid function state. Assessment of ultrasensitive TSH can be recommended as a primary screening test for evaluation of thyroid function in patients under amiodarone therapy.

Amiodarone↗
PubMed1988

[Therapy resistance of amiodarone-induced hyperthyroidism].

The case of a 77-year-old patient who suffered from clinically severe and persistent hyperthyroidism induced by amiodarone is described. Amiodarone-associated hyperthyroidism is a rare (1-5%) but potentially severe complication. Its treatment presents a serious problem. The newer forms of treatment of this specific type of hyperthyroidism with prednisone and perchlorate are described. Under a combined therapy with thionamide drugs, prednisone and perchlorate euthyroidism could be achieved only after months. We propose a simple diagnostic procedure during amiodarone therapy based on the determination of basal ultrasensitive TSH enabling early recognition of amiodarone-associated hyperthyroidism. Thus, with well defined cardiac criteria for therapy with amiodarone as well as early assessment of thyroid dysfunction the incidence of this potentially severe complication can be reduced.

Aged↗
PubMed1988

[Macro-EMG: methodology and problems of determining normal values using the common extensor muscle of the fingers as an example].

The macro-EMG technique registers simultaneously two different potentials from one motor unit. One signal is a single fiber potential, the other an unselective compound recording (macro) of the action potentials of all the muscle fibers within this unit. So motor unit size can be quantified by its electrical activity. Measured data can only be judged upon if normal data are available. These we compiled for the extensor digitorum communis muscle in 83 healthy volunteers. As parameters of the macro-potential amplitude, area and duration were evaluated. It is shown, that amplitude and area are sufficient to characterise a potential. The potential itself is strongly influenced by age and muscle volume. Diagnostic evaluation of the macro-potential is only possible within the context of the results of the single fiber recording and the estimation of fiber density. We found within 105 normal persons a fiber density between 1.2 to 1.9 without a significant dependence on age. With our normal data it is now possible to derive diagnostic conclusions from macro-EMG data.

Adolescent↗
PubMed1987

Controversies in plastic surgery: suction-assisted lipectomy (SAL) and the hCG (human chorionic gonadotropin) protocol for obesity treatment.

The advent of SAL (suction-assisted lipectomy) has dramatically increased the number of obese patients coming to our consultation offices. Despite several articles suggesting a conservative approach to fat suction, some reports insinuate that SAL might be a useful tool for obesity treatment. This hypothesis is refuted by a vast body of evidence that concludes that the adipose tissue may regenerate in adult humans. Therefore, surgical procedures are not advised as the method of choice to manage the disease. On the other hand, the terms obesity and being overweight may not be interchangeable. Obesity may be a disease whereas being overweight is a sign of the disease. Consequently, proper preoperative selection of candidates for SAL becomes mandatory. The hCG (human chorionic gonadotropin) method for obesity treatment appears to be a complete program for the management of obesity. It contains pharmacologic, dietetic, and behavior modification aspects in a 40-day course of treatment. Some data suggest hCG to be lipolytic, thus explaining former clinical observations regarding body fat redistribution in treated patients. hCG commercial preparations contain beta-endorphin, an opioid peptide linked to mood behavior. This article speculates on the possible actions of the complex hCG beta-endorphin in the neuromodulation of mood and energy metabolism. The method comprises a behavior modification that helps in handling the patient better. There are some correlations between a current behavior modification program and the basic guidelines contained in the hCG protocol. Thus, the hCG method appears to be a reasonable alternative in the management of a long-standing, unsolved problem of human metabolism.

Adipose Tissue↗
PubMed1987

Does switching from cigarettes to pipes or cigars reduce tobacco smoke exposure?

Cigarette smoking histories, reported depth of inhalation, number of pipe and cigars (PC) smoked, serum thiocyanate (SCN) and expired air carbon monoxide (CO) levels were examined in PC male smokers enrolled in the Multiple Risk Factor Intervention Trial (MRFIT). Serum SCN levels for all PC smokers were higher than for non-smokers and lower than for current cigarette smokers. Levels were related to the amount of product smoke. Prior cigarette smokers had higher SCN levels when compared to PC users who had never smoked cigarettes, smoked a larger number of tobacco products per day, and reported inhaling into the chest more often. Prospective data on baseline cigarette smokers demonstrated that smokers who stopped all tobacco products had a greater drop in SCN and CO than those who switched to PC. The findings strongly suggest that cessation of all tobacco products is the best strategy for decreasing exposure to tobacco smoke.

Breath Tests↗