Search PubMed⌕ Search

Biomedical subjects

M Vogel

Publications and source records attributed to M Vogel.

At least 307 records · Page 17Linked to original sources
PubMed1989

[The accuracy of Doppler echocardiography determination of shunt volume in children with isolated atrial septal defect and left-right shunt].

The accuracy of shunt calculations derived from Doppler echocardiography was assessed in 15 children (5-15 years, mean 8.5 yrs.) with secundum-type atrial septal defect and left-to-right (L-R) shunt. Qp/Qs was calculated by measuring stroke volumes over the aorta and pulmonary artery prior to and 4-15 days after corrective surgery. The measuring error of the Doppler method was defined as deviation of the postoperative shunt value from zero. A residual shunt was excluded by careful intraoperative testing and physical examination. Intraoperative inspection revealed normal pulmonary venous drainage. L-R-shunt, as calculated by Doppler echo, significantly decreased after surgery (p less than 0.001). Although all septal defects were closed, calculations by Doppler echo resulted in a median residual shunt of 16% (0-50.7%). IN 2/15 children a L-R shunt of more than 40% was derived by echo recordings. The size of the measuring error increased in children with great preoperative shunts. There was a significant correlation between the ratio of pulmonary to aortic cross-sectional area and the measuring error (p less than 0.03, r = 0.59). Poor estimation of cross-sectional areas in dilated pulmonary arteries was the most important limiting factor in shunt calculation. Doppler echocardiography provides a valuable noninvasive method for shunt calculation. Similarly to Fick's principle, in some patients the measuring error may be considerable and become relevant for clinical decisions. Thus Doppler-derived shunt calculations must be complemented by additional information of two-dimensional echo and physical examination.

Adolescent↗
PubMed1989

[Combination therapy with isosorbide dinitrate and verapamil in patients with coronary heart disease and hypertension: effect on blood pressure, ischemia and left ventricular function].

In the treatment of myocardial ischemia in hypertensive patients, nitrates as the basic compound have to be combined with another substance in order to achieve a maximum effect and a 24-h-protection. As these patients often show an impaired left ventricular function because of arterial hypertension or previous myocardial infarction, a further deterioration of the left ventricular ejection fraction (EF) has to be avoided. We therefore investigated in a pilot study. EF, blood pressure, and ST-segment depression under isosorbide dinitrate 120 mg s.r. alone, and in combination with verapamil 120 mg s.r. in 14 male patients with angiographically proven coronary artery disease and arterial hypertension. EF at rest ranged from 29% to 76%. Radionuclide ventriculography was performed at rest and simultaneously with the ECG during exercise before medication, 2 h after ISDN and 4 h after the additional intake of verapamil. The systolic blood pressure at rest fell from 159 +/- 14 to 132 +/- 10 (p less than 0.001) after 2 h and to 132 +/- 16 mmHg after 6 h (p less than 0.01). During exercise there was a decrease from 196 +/- 21 to 174 +/- 21 (p less than 0.01) and to 178 +/- 22 mmHg (p less than 0.001), respectively. The ST-segment depression was reduced from 2.2 +/- 1.1 to 0.8 +/- 0.6 (p less than 0.01) and to 0.9 +/- 0.5 mm (p less than 0.001). EF at rest improved from 53 +/- 14% to 57 +/- 14% after ISDN alone and to 58 +/- 15% after ISDN + verapamil (p less than 0.01), and during exercise from 57 +/- 20% to 62 +/- 19% (p less than 0.05) and to 61 +/- 17% (n.s.). Even in the subgroup of patients with impaired LV-EF (8 at rest and 7 pts during exercise) there was a significant improvement (p less than 0.05) as well after ISDN alone, as there was with combination therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Incidence of cystoid macular edema following cataract extraction].

In a prospective study we research the incidence of cystoid macular edema following intracapsular cataract extraction with the Choyce-Mark-IX implantation method. The only eyes included in the study were those for which the operation had been uncomplicated. Fluorescence angiography was performed after 8 days, 6 weeks, 6 months and 1 year. The edema was graded accordingly: grades I-III. Cystoid macular edema of grade III was demonstrated in 4% after 6 weeks but not after 6 months and 1 year. After 1 year, grade II occurred in 2% and grade I in 15%, respectively. Visual acuity, however, was not impaired.

Aged↗
PubMed1988

An echocardiographic study of the association of ventricular septal defect and right ventricular muscle bundles with a fixed subaortic abnormality.

Since 1983, 36 patients with the combination of right ventricular muscle bundles and a perimembranous ventricular septal defect have been studied in our institution to address the incidence of on associated subaortic abnormality. Of that total 32 (88%) had echocardiographic evidence of such an abnormality (29 had a typical subarotic ridge protruding from the crest of the interventricular septum and the remaining 3 had an echodense area in the same location). Surgical confirmation of the presence or absence of a subaortic abnormality was available in 26. There was correlation between the surgical and echocardiographic findings in all patients. A resting Doppler gradient of greater than or equal to 10 mm Hg was present in only 10. During the study period, 6 patients had Doppler evidence of progression of their gradient. The incidence of subaortic abnormalities in right ventricular muscle bundles and ventricular septal defects appears to be far greater than previously suspected. The exact significance of this finding in the absence of a pressure gradient is still unclear.

Child, Preschool↗
PubMed1988

In vitro expression of cloned PrP cDNA derived from scrapie-infected mouse brain: lack of transmission of scrapie infectivity.

A cDNA for the prion protein (PrP) derived from scrapie-infected mouse brain was expressed in C127 mouse cells in vitro under the control of the mouse metallothionein promoter. PrP synthesis was detected by immunoprecipitation using a rabbit antibody specific for a 15 amino acid PrP peptide. Homogenates of cells expressing the cloned PrP cDNA inoculated into weanling mice failed to induce clinical scrapie during 190 days of observation. We conclude that either PrP is not the transmissible agent of scrapie or the PrP is not processed appropriately in this cell system to create the infectious agent.

Animals↗
PubMed1988

Cellular basis of inflammation-induced osteopenia in growing rats.

Local nonosseous inflammation provoked by four subcutaneous talc powder injections induced a marked trabecular bone loss in rats within 7 days. The disturbance included suppression of bone elongation, inefficiency and decreased number of trabecular osteoblasts, decreased osteoprogenitor cell number in tibial metaphyses, and bone marrow expansion. Neither the appearance and function of osteoblasts in the vicinity of the cortical bone nor the number of osteoclasts in the metaphysis were found to be altered. The loss of trabecular bone in granulomatosis was based on a suppression of bone elongation and a failure of osteoblasts to form normal secondary spongiosa.

Animals↗
PubMed1988

Characterization of a sequence (hlyR) which enhances synthesis and secretion of hemolysin in Escherichia coli.

A sequence (hlyR) of about 600 bp which enhances the expression of hemolysin (HlyA) more than 50-fold was identified in the plasmid pHly152-specific hemolysin (hly) determinant. Deletion of this entire hlyR sequence led to the same low level of hemolysin synthesis and excretion as that expressed by the recombinant plasmid pANN202-312. HlyR was active in cis but its activity was orientation-dependent. The enhancing sequence, hlyR, is separated from the promoter phlyI transcribing hlyC, hlyA and possibly hlyB by more than 1.5 kb including an IS2 element. Stepwise removal of the hlyR sequence from its 5' end by exonuclease III (ExoIII) digestion yielded several types of deletion mutants which expressed decreasing amounts of hemolysin. A similar observation was made when hlyR was shortened by ExoIII from its 3' end, which suggests that more than one functional region may be present in the hlyR sequence. A deletion of 717 bp within the adjacent IS2 element reduced the activity of hlyR only slightly, indicating that IS2 is not directly involved in the enhancement mechanism but that it may support an optimal positioning in hlyR relative to the hly promoter. The nucleotide sequence of hlyR is rich in A + T and does not contain an extended open reading frame, but exhibits several sequence motives that may represent sites for protein binding and DNA bending.

Base Sequence↗
PubMed1988

[The vital staining of nuclear chromatin and the chromosomes of HeLa cells with the fluorochrome AMHA binding to DNA].

The fluorochrome AMHA (3-amino-6-methoxy-9-(2-hydroxyethylamino)acridine) stains the nuclear chromatin and the chromosomes of living HeLa cells. At relatively low dye concentrations CF less than or equal to 10(-4) M and short incubation periods tI less than or equal to 2 h cell growth is not affected by the drug. But at higher CF and longer tI the population doubling time of the cell cultures rapidly increases, and finally the cells die. In vital staining experiments the dye AMHA preferentially binds to the DNA of the nuclei and to the chromosomes of the cells, respectively. The dye binding to DNA has been proved by the absorption and emission microspectra of the stained cells, and by the comparison with authentic spectra of AMHA bound to DNA in aqueous solutions. Within the limits of experimental errors both types of spectra are identical. The spectra of DNA-bound AMHA show a characteristic gap of ca. 3500 cm-1 between the 0-0-transitions of the long wave length 1La absorption and the fluorescence. AMHA molecules dissolved in the polar solvent water have a gap of even 4100 cm-1. This energy gap shows that the electron distribution of AMHA is strongly changed by light absorption and emission. Finally, using absorption spectroscopy, we investigated the binding of AMHA to DNA in aqueous solutions over a wide range of concentrations of the dye, of nucleic acid (calf thymus), and of the competitor NaCl respectively. The Scatchard binding isotherms were determined. With the method of competitive salt effect three different bonds of AMHA to DNA can be distinguished even at low dye concentrations: The intercalation 1 of the fluorochrome F, binding constant KF1 = 1.1.10(5) M-1, binding parameter n1 = 0.15; the pre-intercalative or external binding 2, KF2 = 6.9.10(5) M-1, n2 = 0.21; the external binding 3, KF3 = 2.8.10(5) M-1, n3 = 0.55. Externally bound dye molecules 2 and 3 occupy two phosphodiester residues of the DNA. A detailed discussion of the data and the competitive salt effect shows that in living cells only intercalated and small amounts of pre-intercalatively bound molecules 1 and 2 exist. The binding constant KF1 = 1.1.10(5) M-1 of AMHA is unusual high in comparison with the constants of intercalation of other dyes, KF1 = (1-4).10(4) M-1.(ABSTRACT TRUNCATED AT 400 WORDS)

Aminoacridines↗
PubMed1988

Production of a recombinant antigen of Echinococcus multilocularis with high immunodiagnostic sensitivity and specificity.

A cDNA library derived from mRNA of metacestodes from Echinococcus multilocularis was constructed in the Escherichia coli expression vector lambda gt11 and screened with human patients' sera. The recombinant proteins of 11 positive phages were further evaluated for their potential as immunodiagnostic reagent. One isolated clone (from lysogen II/3) synthesized a fusion protein which was rapidly degraded. This intracellular degradation process provided two distinct polypeptides with Mr of about 31,000 and 33,000, both showing strong binding activity with specific patients' antibodies. The diagnostic value of the II/3-antigen was evaluated by mini-Western-blot with sera from 41 patients infected with E. multilocularis and sera from 77 patients with other helminthic infections, resulting in a diagnostic sensitivity of 98% and an over-all specificity of 96%. These results suggest the usefulness of the recombinant II/3-antigen for immunodiagnosis of human alveolar echinococcosis.

Animals↗
PubMed1988

[The so-called "ocular histoplasmosis syndrome"].

The authors describe seven patients presenting with ophthalmoscopic findings typical of "presumed ocular histoplasmosis syndrome." However, no humoral antibodies could be demonstrated. Moreover, the results of skin tests were all negative even after "boostering." Hence, the diagnosis of ocular histoplasmosis had to be ruled out. Tests for listeriosis, lues, leptospirosis, ornithosis, Toxocara canis, toxoplasmosis, Larva migrans, and Candida albicans were also negative. There are evidently other, so far unknown, agents which lead to an ophthalmoscopic picture that mimics ocular histoplasmosis with its typical "punched-out lesions" and central hemorrhagic chorioretinopathy. One of these agents may be Epstein-Barr virus, because two of six patients had increased antibody levels of Epstein-Barr nuclear antigen and early antigen, indicating an active or persistent state of viral infection.

Adult↗
PubMed1988

[Laser trabeculoplasty in glaucoma chronicum simplex. Results of a prospective, clinical study].

Between 1984 and 1986, 104 patients with open-angle glaucoma of various etiologies were treated by laser trabeculoplasty (LTP) in a prospective clinical study. In order to ensure that the group of patients studied was homogeneous, only the 85 consecutive patients (85 eyes) with primary open-angle glaucoma were included, using a specially designed software program. The number of patients with pseudoexfoliation glaucoma, aphakic glaucoma, and congenital glaucoma was too small to allow statistical comparison with those who had chronic open-angle glaucoma. Criteria for success were defined as follows: no progression of disk cupping or visual field defects, mean intraocular pressure below 24 mm Hg as calculated by a day profile, and no increase in medication. These conditions were satisfied by 76% of the patients after six months and by 64% after 12 months. Initially, coagulations were performed over 180 degrees in the inferior circumference. If this did not suffice, the upper 180 degrees were also coagulated. If LTP is to be effective, thorough coagulation with tender blanching effects is mandatory. Average preoperative pressure values of over 22 mm Hg and a postoperative pressure increase of between 5 and 14 mm Hg are favorable prognostic signs. None of the parameters age, sex, duration, intensity of glaucomatous disease, or preoperative medication had any influence on the efficacy of LTP. In 14 of the 45 patients in whom only one eye was treated a simultaneous decrease in pressure was also observed in the untreated eye. The side effects of LTP bear no relation to its benefits, so that LTP is very suitable as a therapy between medication and surgery. Careful follow-ups of the patients are necessary because of possible increases in intraocular pressure in the course of time.

Aged↗
PubMed1988

In vitro expression in eukaryotic cells of a prion protein gene cloned from scrapie-infected mouse brain.

It has been proposed that the causative agent of scrapie represents a class of infectious particle that is devoid of nucleic acid and that an altered form of the endogenous prion protein (PrP) is the agent. However, it has been difficult to exclude the possibility that PrP purified from scrapie tissues might be contaminated with a more conventional viral agent. To obtain PrP uncontaminated by scrapie-infected tissues, PrP cDNA cloned from a scrapie-infected mouse brain was expressed in mouse C127 cells in vitro. mRNA and protein encoded by the cloned PrP gene were identified. The expressed PrP polypeptides appeared to be glycosylated and were released from the cell surface into the medium. Homogenates of the cells expressing the cloned PrP gene were inoculated into susceptible mice but failed to induce clinical signs of scrapie. Thus, either PrP is not the transmissible agent of scrapie or the expressed PrP requires additional modification to be infectious.

Animals↗
PubMed1988

The insufficient nitrate response: patients' characterization and response to beta and calcium blockade.

Little information has been published regarding the nitrate-induced changes of left ventricular volumes at rest and during exercise in relation to the degree of the anti-ischaemic response. Therefore we assessed the electrocardiographically defined nitrate response to a single tablet of 80 mg isosorbide dinitrate s.r. and compared it to the changes in end-diastolic volumes at rest and during exercise, as determined by radionuclide ventriculography. Thirty-four of the 63 patients were classified as good nitrate responders, whereas 29 patients showed insufficient nitrate response with regard to the reduction of exercise-induced ST-segment depression. The baseline characteristics were quite comparable. At rest the ISDN-induced decrease of the end-diastolic count rate was significantly less (-17%) in patients with insufficient ST-segment response when compared to patients with good ST-segment response (-25%). During exercise, in patients with good ST-segment response, ISDN reduced the end-diastolic volume significantly (-19%), whereas in patients with insufficient ST-segment response the end-diastolic volume remained unchanged. In this special subset of patients with insufficient nitrate response we further evaluated the effects of additional beta or/and calcium blockade. The benefits from verapamil were equivalent to propranolol. However, a considerable part of the patients investigated needed the combination of verapamil and propranolol for an optimal anti-ischaemic drug treatment. Thus, our data support the concept that preload reduction plays a major role for the anti-ischaemic effects of ISDN in patients with exercise-dependent ischaemia. Since, a suboptimal therapeutic effect must be considered, objective control of the nitrate therapy (usually by exercise- and Holter-ECG) must be regarded as obligatory for each individual patient if optimal results are to be expected.

Adult↗
PubMed1988

Influence of diurnal rhythm, posture and right atrial size on plasma atrial natriuretic peptide levels.

A diurnal rhythm of plasma atrial natriuretic peptide (ANP) and cyclic 3'5'guanosine monophosphate (cGMP) was found in nine healthy adult volunteers. Significantly higher levels of both parameters were found in the morning (8 a.m.) than later during the day and night (p less than 0.05). Different postures had only a little influence on plasma ANP and cGMP levels in seven healthy adult volunteers using a tilt table. Tilted from supine into upright, head-down (-20 degrees) and then again into supine posture, significant differences of both parameters were only found between levels shortly after the end of the upright posture and those at the end of the head-down posture (p less than 0.05). Furthermore, in infants with various congenital heart diseases (n = 19) and control infants (n = 35) the right atrial area was determined by two-dimensional echocardiography and related to plasma ANP levels. Out of 19 infants with cardiac disease, 11 showed an enlarged right atrial area (i.e. above the 95th percentile in the range of control infants). All these 11 infants also had higher plasma ANP levels (range 115-670 pg/ml) than the healthy infants (range 5-98 pg/ml). These data support the assumption that atrial wall distension seems to be a stimulus for ANP release.

Adult↗