PubMed Health⌕ Search

Biomedical subjects

M Baden

Publications and source records attributed to M Baden.

At least 19 recordsLinked to original sources
PubMed2001

Early identification of impaired myocardial reperfusion with serial assessment of ST segments after percutaneous transluminal coronary angioplasty during acute myocardial infarction.

To evaluate the relation between ST-segment analysis and microvascular reperfusion in patients with acute myocardial infarction (AMI), we studied 51 patients with first AMI who were successfully treated by percutaneous transluminal coronary angioplasty (PTCA). The lead showing the greatest ST-segment elevation on the 12-lead electrocardiogram (ECG) was serially investigated until 24 hours after PTCA. Successful reperfusion was determined by technetium-99m tetrofosmin single-photon emission computed tomography. Impaired reperfusion (group 1: < 4 change in the sum of the defect score from before to immediately after PTCA) was observed in 24 patients, and successful reperfusion (group 2) was observed in 27 patients. Although ST-segment elevation was reduced significantly at 30 minutes after PTCA in group 2 (2.2 +/- 1.4 to 1.7 +/- 1.3 mm, p = 0.01), there was no significant change in group 1 (1.9 +/- 1.9 to 2.4 +/- 1.7 mm). Ten of 14 patients (71%) with persistent ST-segment elevation (DeltaST > 0 mm change in ST segment from before to 30 minutes after PTCA > 0) were in group 1, whereas 23 of 37 patients (62%) with ST-segment resolution (DeltaST < or = 0) were in group 2. The sensitivity and specificity of persistent ST-segment elevation for predicting impaired microvascular reperfusion were 42% and 85%, respectively. Thus, persistent ST-segment elevation 30 minutes after primary PTCA was a highly specific electrocardiographic marker of impaired reperfusion in patients with AMI.

Aged↗
PubMed2001

Accuracy of technetium-99m tetrofosmin myocardial perfusion imaging in the detection of spontaneous recanalization in patients with acute anterior myocardial infarction.

To avoid the haemorrhagic risk of unnecessary thrombolysis in acute myocardial infarction (MI), early and precise diagnosis of spontaneous recanalization (SR) of the infarct-related artery is required. To clarify the accuracy of technetium-99m tetrofosmin myocardial single-photon emission tomography (SPET) in the detection of SR in patients with acute anterior MI, electrocardiography (ECG), echocardiography and 99mTc-tetrofosmin SPET imaging were performed in 49 patients with acute anterior MI before emergency coronary angiography. Defect score was calculated as the sum of the perfusion defects of each segment: from 3 (complete defect) to 0 (normal perfusion). Echocardiographic asynergic score (the sum of asynergic grades) and the greatest ST elevation of the 12-lead ECG on admission were also measured. SR was defined as Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow on emergency coronary angiography. Defect score in 11 patients with SR (9.2 +/- 3.7) was significantly lower than that in 38 patients without SR (18.5 +/- 5.0) (P < 0.001), whereas there were no significant differences in asynergic score and ST elevation between the two groups. From the receiver operating characteristic curves, the optimal cut-off points of defect score, asynergic score and ST elevation for the detection of SR were calculated to be 12, 13 and 3.5, respectively. The sensitivity and specificity of the scintigraphic defect score (91% and 89%) were significantly higher than those of the asynergic score (64% and 68%) and ST elevation (73% and 71%). Thus, 99mTc-tetrofosmin SPET imaging on admission is a very accurate method for the detection of SR in patients with acute anterior MI.

Acute Disease↗
PubMed1999

Early detection of the no-reflow phenomenon in reperfused acute myocardial infarction using technetium-99m tetrofosmin imaging.

Evaluation of myocardial perfusion in the early stage of acute myocardial infarction (MI) is clinically important for adjunctive therapies to minimize infarct size. To determine the role of early scintigraphic detection of impaired myocardial reperfusion after primary coronary angioplasty (PTCA) in patients with acute MI, semiquantitative technetium-99m tetrofosmin single-photon emission tomographic (SPET) imaging was performed before primary PTCA (before; area at risk), 60 min after PTCA (after) and at 1 month (1 M; final infarct) in 35 patients with acute MI. The left ventricle was divided into 13 segments and the defect score was calculated as the sum of the perfusion defect of each segment, from 3 (complete defect) to 0 (normal perfusion). A significant myocardial perfusion change after PTCA was defined as a change in the defect score (before minus after PTCA) of >/=4. The echocardiographic asynergic score was defined as the number of asynergic (severe hypokinetic or akinetic) segments corresponding to the analogous segments on SPET images, and recovery of wall motion was calculated as absolute change in the asynergic score (before PTCA minus 1 M). Among the 35 patients, 15 (43%) had a change in the defect score of <4 (no reflow: group 1) while 20 had a change in the defect score of >/=4 (reflow: group 2). There were no significant differences between the two groups with respect to the time between admission to PTCA, revascularization time, collateral grade or Thrombolysis in Myocardial Infarction (TIMI) flow grade before PTCA. Despite the lack of a difference in area at risk between the two groups (group 1 = 12.8+/-4.3 and group 2 = 15.1+/-4.7), final infarct size in group 1 was significantly larger compared with that in group 2 (8.1+/-4.3 vs 4.9+/-3.0, P<0.001). Recovery of wall motion was significantly smaller in group 1 than in group 2 (4.3+/-1.7 to 3.5+/-1.5 vs 4. 1+/-2.1 to 1.6+/-1.6, P<0.001). In conclusion, a small change (<4) in defect score (scintigraphic no-reflow phenomenon) after primary PTCA indicates persisting impaired myocardial perfusion or irreversible cellular damage just after PTCA which is associated with poor recovery of wall motion, as compared with that observed in cases of reflow (>/=4 in defect score).

Aged↗
PubMed1998

Coronary artery diameter and left ventricular function in patients on maintenance hemodialysis treatment: comparison between diabetic and nondiabetic patients.

BACKGROUND/AIMS: This study examined the role of diabetes mellitus on determining left ventricular function by evaluating coronary artery diameter in patients with end-stage renal disease on maintenance hemodialysis treatment. METHODS: We studied 12 diabetic and 12 nondiabetic patients on maintenance hemodialysis treatment without significant stenoses of the major epicardial coronary arteries. Patients were matched for age, sex distribution, duration of dialysis and incidence of major coronary risk factors. Left ventricular wall thickness (septal and posterior walls) and left ventricular diameter (end-diastolic and systolic phases), were measured by echocardiography. Hemodynamic measurements and coronary angiography were performed on the day of hemodialysis and coronary artery diameter at the proximal and mid portion of three major coronary arteries were measured using the computed densitometry method. RESULTS: Right and left anterior descending and circumflex coronary artery diameters were all significantly smaller and the frequency of coronary artery calcification was higher in diabetic (58%) compared to nondiabetic (8%) patients. Although there were no significant differences in left ventricular wall thickness, left ventricular diameter, mean right atrial pressure and cardiac index between the two groups, left ventricular end-diastolic pressure was significantly higher in diabetic (22 +/- 9 mm Hg) compared to nondiabetic patients (14 +/- 5 mm Hg). CONCLUSION: Despite that there were no significant stenoses of the major epicardial coronary arteries, diffuse luminal narrowing of the epicardial coronary arteries in diabetic patients on maintenance hemodialysis treatment was associated with increased left ventricular end-diastolic pressure.

Aged↗
PubMed1994

Receptor-stimulated guanine-nucleotide-triphosphate binding to guanine-nucleotide-binding regulatory proteins. Nucleotide exchange and beta-subunit-mediated phosphotransfer reactions.

In order to study whether phosphate transfer reactions are involved in the binding of guanine nucleotide triphosphates to guanine-nucleotide-binding regulatory proteins, binding of the GTP analogues, guanosine 5'-[gamma-thio]triphosphate, GTP[S], and guanosine 5'-[beta, gamma-imino]triphosphate, p[NH]ppG, and the regulation of binding by the formyl-peptide-receptor agonist, fMet-Leu-Phe, were studied in membranes of differentiated HL-60 cells. For fMet-Leu-Phe-stimulated binding of either GTP analogue, a competing nucleotide was required. With GDP as the competing nucleotide, initial rates of fMet-Leu-Phe-stimulated binding of GTP[S] and p[NH]ppG were similar for up to approximately 30 s. Thereafter, receptor-stimulated binding of p[NH]ppG rapidly reached equilibrium, whereas the binding of GTP[S] proceeded further. At equipotent concentrations of p[NH]ppG and GTP[S], maximal fMet-Leu-Phe-stimulated binding of GTP[S] was approximately twofold higher than that of p[NH]ppG. Finally, for half-maximal receptor-stimulated binding of GTP[S], approximately fivefold higher concentrations of both Mg2+ and GDP were required than for p[NH]ppG binding. With p[NH]ppG as the competing nucleotide, the extent of receptor-stimulated binding of GTP[S] as well as its Mg2+ requirement and time course were similar to the receptor-stimulated p[NH]ppG binding observed in the presence of GDP. However, with GTP[S] as the competing nucleotide, fMet-Leu-Phe reduced the binding of p[NH]ppG, a reaction further enhanced when GDP was additionally present. Under similar conditions as used in the binding studies, GTP[S] thiophosphorylated a 35-kDa protein, which is most likely a guanine-nucleotide-binding regulatory protein beta subunit [Wieland, T., Nürnberg, B., Ulibarri, I., Kaldenberg-Stasch, S., Schultz, G. & Jakobs, K. H. (1993) J. Biol. Chem. 268, 18111-18118]. The thiophosphorylation state of this protein was regulated by guanine nucleotides, Mg2+ and, most importantly, by activated formyl-peptide receptors. The data thus provide evidence for an essential difference between GTP[S] and p[NH]ppG binding to guanine-nucleotide-binding regulatory proteins and suggest that, in addition to the nucleotide-exchange reaction, a (thio)phosphate-group-transfer process via guanine-nucleotide-binding regulatory protein beta subunits is involved in the receptor-stimulated binding of guanine nucleotide triphosphates to guanine-nucleotide-binding regulatory proteins.

Binding, Competitive↗
PubMed1989

Relationship between the coronary diameter and occurrence of vasospastic angina in patients with normal coronary arteries.

Coronary artery diameters were measured after various interventions in 30 patients without angina pectoris (group 1) and in 15 with angina pectoris (group 2: rest, or rest and effort angina) who had normal coronary arteries. The coronary artery diameters were significantly smaller in many coronary segments in group 2 than in group 1 during a control state, after exercise and ergonovine, but became nearly identical after isosorbide dinitrate in both groups. Patients in group 1 had diffuse narrowing but no focal vasoconstriction after ergonovine and all the segments had a diameter of more than 50% of that after isosorbide dinitrate. The change of coronary artery diameter in group 2 patients who had no vasospasm by ergonovine was the same as that in group 1. Patients in whom vasospastic angina was induced had local vasoconstriction or severe diffuse narrowing (less than 45%). These results indicate that angina pectoris patients with normal coronary arteries had an acceleration of coronary arterial basal tone, but vasospastic angina pectoris was not induced just by the general response of the coronary artery to various interventions in addition to the accentuated basal tone. For vasospastic angina to occur, local abnormal response to various interventions must be present.

Adult↗
PubMed1979

Patterns and intensity of autofluorescence and its relation to melanin in human epidermis and hair.

The skin of 41 patients including 16 blacks, 15 Caucasians, and 10 Hispanics, was observed using a fluorescent microscope. Three patterns of autofluorescence were observed: intercellular, cytoplasmic, and a combination of intercellular and cytoplasmic. The hair of 75 subjects, including 18 Negroes and 55 Caucasians, was observed. Two patterns were found: medullar and at the cortex. Skin form black patients was associated with the cytoplasmic pattern of autofluorescence. Compared to lighter skin, black skin was also significantly associated with increased intensity of autofluorescence, indicating that autofluorescence of the epidermis parallels the clinical degree of pigmentation. In the hair of 75 subjects, similar results were obtained: Negro hair exhibited more fluorescence than Caucasian hair, and darker hair (brown to black) exhibited more fluorescence than lighter hair (blond). This may be related to melanin and it breakdown products.

Black People↗
PubMed1975

The first year of the toxicology program.

The CAP Toxicology Survey Program's initial year is reviewed. Four series of samples, each consisting of five specimens with approximately 12 different drugs, were sent to almost 200 participants and as many as seven referees. They reported the presence or absence of more than 16 different compounds, and identified specific barbiturates when present. In each series, two serum samples were for qualitative identification and quantitative analysis. The remainder were urine samples for qualitative analysis. The aim of the survey is to enhance the "current state of the art" among participants. Drug-abuse toxicology and therapeutic monitoring of drugs were given priority. Clinically relevant samples reflecting current drug abuse, especially mixed-drug abuse, were provided, including serum for quantitative determination as is required in treatment of barbiturate overdose and for therapeutic drug monitoring. The Committee has interacted with participants by critiques of surveys, by questionnaires, and by responding to queries from participants.

Amphetamine↗