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T Hofmann

Publications and source records attributed to T Hofmann.

At least 73 records · Page 4Linked to original sources
PubMed1998

Effects of topically delivered benzamil and amiloride on nasal potential difference in cystic fibrosis.

The raised nasal transepithelial potential difference (PD) in cystic fibrosis (CF) reflects accelerated active transport of Na+, and is inhibited by topical administration of the Na+ channel blocker, amiloride. The aim of this study was to investigate the dose-effect and time course of topically administered Na+ conductance inhibitors to inhibit nasal PD, including benzamil, an analog of amiloride. We measured the magnitude of drug inhibition of Na+ transport [percent inhibition of baseline PD (DeltaPD%)] and duration of inhibition of PD, defined as the time when drug inhibition of PD had recovered by 50% (effective time = ET50). Amiloride [10(-)3 M (n = 16), 3 x 10(-)3 M (n = 9), 6 x 10(-)3 M (n = 7), 10(-)2 M (n = 3)] or benzamil [1.7 x 10(-)3 M (n = 7), and 7 x 10(-)3 M (n = 5)] were administered to the nasal surface via an aerosol generated by a jet nebulizer and a nasal mask. The concentration-dependent magnitude (DeltaPD%) of inhibition was similar for amiloride and benzamil ( approximately 67- 77%), whereas the duration of inhibition (ET50) was about two-and-a-half times longer after benzamil administration as compared with equivalent concentrations of amiloride [1.6 +/- 0. 06 versus 4.5 +/- 0.6 h (ET50 +/- SEM), at 6-7 x 10(-)3 M]. In vitro studies of cultured normal nasal epithelia demonstrated directly that benzamil induced an approximately 2-fold more prolonged inhibition of active Na+ transport than amiloride. These data suggest aerosolized benzamil is a candidate long-duration Na+ channel blocker for CF.

Administration, Intranasal↗
PubMed1997

[Resuscitation in ventricular fibrillation as the first manifestation of Bland-White-Garland syndrome in adulthood].

CASE REPORT: This case presents a 31-year-old male patient with anomalous origin of the left coronary artery from the pulmonary trunc. First symptom of the disease was a survived sudden cardiac death. Subsequent angiographic and echocardiographic studies demonstrated the anomalous origin of the left coronary artery from the pulmonary artery. There were no signs of prior myocardial infarction. After reimplantation of the anomalous originating left coronary artery no myocardial ischemia could be detected in the thallium-201 myocardial imaging, which was present before surgical correction. In this case myocardial ischemia was the only potential triggering mechanism responsible for the sudden cardiac death, which was no longer detectable after surgical correction. Therefore no additional pharmacological and nonpharmacological antiarrhythmic treatment was initiated. CONCLUSION: In rare cases the first manifestation of Bland White Garland syndrome in the adult patient could be sudden cardiac death due to ventricular fibrillation.

Adult↗
PubMed1997

Short-term hemodynamic effects of immunoadsorption in dilated cardiomyopathy.

BACKGROUND: Previous studies have shown that the sera of many patients with dilated cardiomyopathy (DCM) are positive for several antibodies directed against cardiac antigens. Anti-beta1-adrenergic receptor antibodies occur in 70% to 90% of DCM patients. These antibodies are extractable by immunoadsorption (IA). In an investigation of the functional significance of antibodies for hemodynamics, IA was performed throughout 5 consecutive days on nine patients with severe DCM who were on stable drug therapy. METHODS AND RESULTS: Immunoglobulins were eliminated in nine patients with severe DCM (mean age, 43.5 years; range, 25 to 58 years; left ventricular ejection fraction, <25%). IA was performed over 5 consecutive days with an immunoadsorber for immunoglobulin. All patients were on stable medication, including ACE inhibitors, digitalis, and diuretics. All patients received beta-blockers. During therapy, hemodynamic parameters (mean+/-SD) were monitored with a Swan-Ganz thermodilution catheter. IA elicited a decrease of anti-beta1-adrenergic receptor antibodies from 6.4+/-1.3 to 1.0+/-0.5 relative units. During IA, cardiac output increased from 3.7+/-0.8 to 5.5+/-1.8 L/min, P<.01. Mean arterial pressure decreased from 76.0+/-9.9 to 65.0+/-11.2 mm Hg, P<.05; mean pulmonary arterial pressure, from 27.6+/-7.7 to 22.0+/-6.5 mm Hg, P<.05; left ventricular filling pressure, from 16.8+/-7.4 to 12.8+/-4.7 mm Hg, P<.05; and systemic vascular resistance, from 1465+/-332 to 949+/-351 dyne x s x cm(-5), P<.01. CONCLUSIONS: In addition to conventional medical treatment, IA may be an additional therapeutic possibility for acute hemodynamic stabilization of patients with severe DCM.

Adult↗
PubMed1997

Routine immunizations in adult renal transplant recipients.

BACKGROUND: Vaccination guidelines for transplant recipients include regular boosters of tetanus, diphtheria, and inactivated polio vaccine, but there are few published data on the efficacy of these vaccines in patients receiving immunosuppressive therapy. METHODS: Serum antibody values were evaluated before and 4 weeks after tetanus, diphtheria, and inactivated polio vaccination in 164 renal transplant recipients compared with healthy controls. Twelve months later, antibody levels were evaluated in 55 patients. RESULTS: Prebooster tetanus antitoxin values were lower in transplant recipients than in controls. All patients developed protective tetanus antibody levels (> or = 0.01 IU/ml) after vaccination. After 12 months, serum antibodies had decreased, but all patients maintained protective values. Diphtheria antitoxin titers before and after booster vaccination were lower in patients than in controls: 88.5% of patients and 96.2% of controls developed protective diphtheria antibody values. Twelve months after vaccination, diphtheria antitoxin values were below the protective level (0.1 IU/ml) in 38% of patients. Prebooster antibody values to poliovirus types 1 and 3 were comparable in patients and controls, whereas antibodies to poliovirus type 2 were lower in transplant recipients. Seroprotection rates and geometric mean antibody titers after vaccination were equivalent between the two groups for all three poliovirus types. No difference was observed in antibody levels between patients on different immunosuppressive drug regimens. Adverse reactions were significantly less often reported by transplant recipients. CONCLUSIONS: In transplant recipients, tetanus and inactivated polio vaccinations are well tolerated and induce protective antibody levels; diphtheria vaccination as currently recommended is less effective and protective antitoxin values decrease rapidly in these patients within 1 year after vaccination.

Adolescent↗
PubMed1997

Cystic fibrosis and non-cystic-fibrosis human nasal epithelium show analogous Na+ absorption and reversible block by phenamil.

Transepithelial short-circuit current (ISC), potential (VT) and resistance (RT) of confluent monolayers of human nasal epithelium cultured from patients with and without cystic fibrosis (CF) were measured. In our Ussing chamber experiments with monolayers derived from non-CF and CF patients neither ISC (non-CF: 14.1 +/- 1.0 microA/cm2, n = 77; CF: 16.7 +/- 1.5 microA/cm2, n = 42), nor RT (non-CF: 288 +/- 15 Omega . cm2; CF: 325 +/- 20 Omega . cm2) showed any significant differences, only VT showed moderate but significant different values (non-CF: -3.6 +/- 0.4 mV; CF: -5.6 +/- 0.7 mV, respectively). Total ISC in CF cells was nearly completely inhibited by amiloride (92 +/- 9.6%), while in non-CF tissue amiloride-insensitive conductances mediated a considerable amount of the ISC (36.3 +/- 6.1%), indicating a lower activity of amiloride-sensitive Na+ conductances in non-CF cells. In both tissues the amiloride-sensitive ISC could also be blocked by the amiloride analogues benzamil, phenamil and 5-(N-ethyl-N-isopropyl)2', 4'-amiloride (EIPA) with different affinities. However, amiloride had a significant lower affinity in CF tissue (half-maximal blocker concentration, K1/2 = 586 +/- 59 nM) compared with non-CF tissue (K1/2 = 294 +/- 22 nM). Astonishingly, phenamil, a blocker which irreversibly blocks all epithelial Na+ channels hitherto described, inhibited the Na+ conductances of human nasal epithelium in a completely reversible way, but nevertheless with high affinity (non-CF: K1/2 = 12.5 +/- 1.2 nM; CF: K1/2 = 17.1 +/- 1.1 nM). Even in high doses none of these blockers had any effect on intracellular Ca2+ concentration as measured with Fura-2. From these findings, we conclude that the epithelial Na+ conductances of human CF nasal epithelium show modified regulation or are functionally different from those of other tissues.

Amiloride↗
PubMed1997

Subthreshold stimulation in the region of the slow pathway during atrioventricular node reentrant tachycardia: correlation with effect of radiofrequency catheter ablation.

OBJECTIVES: The present study sought to investigate the role of subthreshold stimulation in patients with atrioventricular node reentrant tachycardia (AVNRT) undergoing catheter ablation of the slow pathway. BACKGROUND: Subthreshold stimulation applied to right atrial sites has been demonstrated to terminate AVNRT but has not been correlated with the effects of radiofrequency current delivery to the area of the slow pathway. METHODS: Eighteen patients with common AVNRT were prospectively included in the study. Sustained AVNRT was reproducibly inducible in all patients (cycle length 334 +/- 58 ms). Anatomic and electrogram guided mapping of the slow pathway was started posteroseptally and continued to more midseptal sites if required. Subthreshold stimulation (3 s, up to 5 mA) during induced AVNRT was performed at each site eligible for slow pathway ablation until termination of AVNRT or capture was observed. Irrespective of the effect of subthreshold stimulation, radiofrequency current was delivered at each site after exclusion of catheter dislocation. RESULTS: Termination of AVNRT due to block of the anterograde slow pathway induced by subthreshold stimulation occurred without apparent capture in 15 of 18 patients. This phenomenon was exclusively observed at successful posteroseptal to midseptal ablation sites. Subthreshold stimulation was not successful at any of 30 target sites with ineffective radiofrequency current delivery. Thus, subthreshold stimulation identified successful target sites with 83% sensitivity and 100% specificity. Atrioventricular node reentrant tachycardia was abolished in all patients after a median of two (range one to nine) radiofrequency current applications. CONCLUSIONS: Subthreshold stimulation delivered to the region of the slow pathway terminates AVNRT with high safety and efficacy. High sensitivity and specificity for prediction of the effect of radiofrequency current application suggest that subthreshold stimulation may become a new tool for identifying target sites for slow pathway ablation.

Adult↗
PubMed1997

Aerosolized amiloride: dose effect on nasal bioelectric properties, pharmacokinetics, and effect on sputum expectoration in patients with cystic fibrosis.

Aerosolized amiloride normalizes the excessive sodium absorption cystic fibrosis (CF) respiratory epithelium. The aims of this study were to assess the dose-effect relationship and the duration for which amiloride inhibits Na+ transport, to determine acute and chronic pharmacokinetics, and to test the effect of acute aerosolized amiloride on the amount of sputum expectorated. The effect of inhaled amiloride was assessed principally by nasal potential difference (PD) measurements. Amiloride serum levels were measured in 23 patients after inhalation of different doses of aerosolized amiloride. Twenty CF patients inhaled amiloride (10(-3)M) or a placebo in a double-blinded, randomized order, and sputum production was quantitated. The results of this study showed that maximal initial PD inhibition was achieved by 6 x 10(-3)M of amiloride. The duration of inhibition of PD (effective time until return to 50% delta PD [ET50] after nasal administration) was dose dependent (10(-3)M, 39 +/- 0.8 minutes; 10(-2)M; 133 +/- 14 minutes). Amiloride serum levels were below 2.5 ng/ml in 20 of 28 patients; levels were above 5 ng/ml only within 4 hours after high dose inhalation (10(-2)M). In the double-blinded, crossover study, more sputum was expectorated after amiloride inhalation as compared with that after a placebo (P < 0.05). In conclusion, the bioelectric effects of amiloride and serum levels after inhalation are dose dependent, and amiloride is effective at inducing sputum expectoration in CF.

Administration, Intranasal↗
PubMed1996

Radiofrequency current catheter ablation of accessory atrioventricular pathways in Ebstein's anomaly.

BACKGROUND: In patients with Ebstein's anomaly, localization of accessory pathways (APs) may be impeded by abnormal local electrograms recorded along the atrialized right ventricle and by the presence of multiple APs. The impact of these factors on radiofrequency (RF) current catheter ablation of APs has not been evaluated yet. METHODS AND RESULTS: Twenty-one patients with Ebstein's anomaly and reentrant atrioventricular tachycardias underwent electrophysiological evaluation and subsequent attempts at RF catheter ablation. Thirty-four right-sided APs were found, with 30 located along the atrialized ventricle. Local electrograms in this region were normal in 10 patients but fragmented in 11. Fragmented electrograms prevented the clear distinction between atrial and ventricular activation potentials as well as the identification of AP potentials. Right coronary artery mapping was performed in 7 patients. Abolition of all 26 APs was achieved in the 10 patients with normal local electrograms and in 6 of 11 patients with abnormal electrograms. Right coronary artery mapping allowed AP localization and ablation in 5 patients. In the 5 patients with abnormal electrograms and a total of 8 APs, 6 APs could not be ablated. Unsuccessfully treated patients received antiarrhythmic drugs. During 22 +/- 12 months of follow-up, 5 patients had clinical recurrences, including 4 who had undergone a successful RF procedure. CONCLUSIONS: In patients with Ebstein's anomaly and reentrant atrioventricular tachycardias, factors likely to account for failure of RF catheter ablation include an AP located along the atrialized right ventricle and the abnormal morphology of endocardial activation potentials generated in this region.

Action Potentials↗
PubMed1996

Diagnosis of patent foramen ovale by transesophageal echocardiography and correlation with autopsy findings.

Transesophageal echocardiography (TEE) is accepted as the method of choice for the diagnosis of the patent foramen ovale (PFO). However, direct anatomic confirmation regarding the presence or absence of a PFO on transesophageal imaging has been obtained in only a limited number of patients. Consequently, this study was performed to assess the diagnostic accuracy of contrast and color Doppler TEE for detection of a PFO by comparing the results of TEE with autopsy. The study population comprised 35 consecutive patients (mean age 64 +/- 14 years) who underwent autopsy and prior TEE with examination of the atrial septum. For diagnosis of a PFO, the following criteria were used: (1) no defect in the continuity of the atrial septum on 2-dimensional imaging; (2) > or = 1 bright microbubble appearing in left the atrium within 3 heart cycles after opacification of the right atrium during contrast TEE; and (3) turbulent color jet within the atrial septum by color Doppler TEE. For estimating the PFO size, positive contrast studies were graded semiquantitatively (from 1 to 3), and the maximal color Doppler jet width was measured within the atrium septum at the area of maximal turbulence. At autopsy, a PFO was present in 9 of 35 patients (26%). All were correctly diagnosed by color Doppler TEE. The color Doppler jet width correlated well with the PFO diameter determined at autopsy (r=0.99, SEE=0.51 mm, p<0.0001). By contrast TEE, 8 of the 9 patients with autopsy-proven PFO were correctly identified. In 1 case with left heart disease and a long interatrial channel, a PFO was missed by contrast TEE but clearly demonstrated by color Doppler TEE. All patients with a PFO diameter >10 mm showed intense left atrial opacification of grade 3. With both methods, there were no false-positive results. Sensitivity and specificity for diagnosis of a PFO were 89% and 100% respectively, for contrast TEE, and both 100% for color Doppler TEE. Thus, contrast and color Doppler TEE are complementary and represent a highly sensitive and specific method for diagnosis of a PFO and for estimation of the PFO size.

Adult↗
PubMed1996

Acute inhalation toxicity testing: considerations of technical and regulatory aspects.

The EU regulatory statute for the acute hazard identification of chemicals requires selection of the two most appropriate routes of administration. Testing employing the oral route is mandatory, whereas selection of the dermal or inhalation route requires expert judgement, i.e. considerations of structural alerts with regard to the inherent acute inhalation toxicity as well as the likelihood of dermal and inhalation exposure, respectively. Currently, testing of chemicals requires acute inhalation exposure of 4-h and 1-h durations according the EU classification and labelling and UN Transport Guidelines, respectively. The analysis made revealed that 1-h exposures appear to add little knowledge in addition to existing 4-h LC50 values and a default value of 4 should be used for conversion of 4-h to 1-h LC50 values, independently of the physical state of the chemical. Therefore, also the unit of concentration of exposure atmospheres should be independent of nominal features of the test substance. Hence, the preferred dose metric is mass (mg/liter air) rather than volume (ppm). Taking into account the overall variability of acute toxicity data the recommendations given are classification into the following groups of 4-h LC50 values: < or = 0.05, > 0.05-0.2, > 0.2-1, > 1-5 and > 5.0 mg/l. No distinction should be made concerning vapours and aerosols with regard to units and conversion factors from 4-h to 1-h LC50 values and the default factor of 4 appears to be most suitable. Further differentiation of classification is not indicated due to technical variability of acute inhalation testing and resolution of the acute bioassay.

Administration, Inhalation↗
PubMed1996

[Diastolic left ventricular dysfunction with microvascular angina (Syndrome X)].

Findings on left ventricular function in microvascular angina (syndrome X) are somewhat controversial. Recently, an increased prevalence of insulin resistance and hyperlipoproteinemia has been demonstrated as well as arterial hypertension potentially impairing the left ventricular diastolic function. In an attempt to analyze the diastolic function at rest, we investigated by Doppler echocardiography the transmitral blood flow in 16 patients (51 +/- 8 years). The diastolic data were compared with those of 12 healthy people (50 +/- 6 years) who were matched for age. The patients with microvascular angina revealed a slightly higher systolic blood pressure (134 +/- 18 mm Hg vs 125 +/- 9 mm Hg, n.s.), but imposed by higher left ventricular mass index (92 +/- 18 g/m2 vs 65 +/- 13 g/m2, p < 0.001). There was a trend to an elevated A-wave-peak during transmitral blood flow (61 +/- 14 cm/s vs 50 +/- 9 cm/s). The findings suggest impairment of the left ventricular relaxation before manifestation of left ventricular hypertrophy and hypertension takes place.

Adult↗
PubMed1996

Diagnosis, localization and evaluation of malignancy of heart and mediastinal tumors by conventional and transesophageal echocardiography.

Transesophageal echocardiography is well established in detecting and diagnosing heart tumors. In contrast, its role in assessing presence, growth and evidence of malignancy of tumors originating from the mediastinal site remains widely uncertain. In a prospective and investigator-blind study, we evaluated 72 consecutive patients with cardiac and/or mediastinal tumor lesions to assess the diagnostic impact of transthoracic and transesophageal echocardiography in determining localization, growth and malignancy. All tumor lesions were diagnosed and carefully evaluated by computer tomography and/or magnetic resonance imaging prior to the study. Biopsy demonstrated a malignant tumor in 49 patients and a benign tumor in 23 patients. Transthoracic and transesophageal echocardiography were equally effective in visualizing tumors of the heart in 24 patients (92% vs 100%; N.S.). Tumors originating from the mediastinum were 2.9 times less likely to be detected by the transthoracic approach (p < 0.001). In these patients, transesophageal echocardiography was also superior in diagnosing myocardial infiltration (18 vs 4 patients, p < 0.001) and invasion or intracardiac growth of the tumor (13 vs 6 patients, p < 0.05). When compared to histological findings, transesophageal echocardiography predicted malignancy from the presence of tumor spread both in- and outside the heart, infiltration and invasion in 21/49 patients (43%), a false positive result was obtained in only 1/23 patients with a benign tumor. Conventional echocardiography predicted malignancy in only 4/49 patients (8%, p < 0.005). In conclusion, transesophageal echocardiography is increasingly used in patients with suspected mediastinal tumor lesions. Our study demonstrates, that transesophageal echocardiography is effective and superior to the conventional approach in predicting localization and growth of mediastinal tumors, as well as in accessing evidence of malignancy of the tumor.

Echocardiography↗
PubMed1996

Clinical pharmacokinetics of tacrolimus in rescue therapy after renal transplantation.

Tacrolimus, a potent new immunosuppressive drug, was introduced for rescue therapy in 25 renal transplant recipients with ongoing rejection (n = 24) or severe cyclosporine toxicity (n = 1). A highly significant (p < 0.001) rise in serum creatinine from 138 +/- 14 (3 months before conversion) to 295 +/- 26 mumol/l preceded conversion to tacrolimus. Tacrolimus rescue therapy started 73 +/- 9 months after transplantation, the follow-up was 8 +/- 1 months. Outcome, pharmacokinetics, and side-effects were analyzed. Patient survival was 100% on tacrolimus therapy. Graft survival was 88% after 3 months, and 70% after 8 months. Serum creatinine remained stable during the observation period (Crea after 8 months: 271 +/- 26 mumol/l). Starting with an initial dose of 9.6 +/- 0.3 mg/day (0.14 +/- 0.01 mg/kg/day) we could reduce tacrolimus dose to 6.0 +/- 0.9 mg/day (0.09 +/- 0.02 mg/kg/day; p < 0.001) after 1 month. Tacrolimus trough levels were adjusted to a therapeutic window of 5-8 ng/ml. We had to perform 3.4 +/- 0.5 dose adjustments per patient mainly within the first month after conversion (70%). A high variability in interindividual tacrolimus dose was noted. Last cyclosporine dose was a good predictor of required tacrolimus dose after 1 month (r = 0.88; p < 0.001). Overall, 82 adverse events were noted, of which 29 (35%) were associated with high trough levels (> 10 ng/ml). In contrast, 3 patients with trough levels < 4 ng/ml had ongoing rejection. Blood pressure and routine laboratory data remained unchanged. Steroid dose could be tapered from 12 +/- 2 to 5 +/- 0.3 mg/day (p < 0.02). Gingival hyperplasia and hirsutism improved after conversion. We conclude: Tacrolimus conversion for rescue therapy after renal transplantation is efficient and safe with target trough levels between 5 -8 ng/ml. Frequent drug monitoring is necessary, especially within the first month after conversion. Previous cyclosporine dose can be used as a guideline for starting dose.

Adult↗
PubMed1995

Chimeric envelope glycoproteins constructed between amphotropic and xenotropic murine leukemia retroviruses.

A set of chimeric envelope proteins between amphotropic and xenotropic murine leukemia retroviruses (MuLV), two closely related members in the MuLV family, were constructed. The purpose was to examine the regions that could be successfully exchanged between these two similar viral envelope proteins. The data indicate that fully active chimeras can be built when the junction is either at the EcoRI site (amino acid 169) 42 amino acids N-terminal to the polyproline hinge of gp70 (named CH4) or at the ScaI site (aa 593) in the membrane spanning portion of p15E (CH1). However, a chimera at the AflII site (aa 125, CH5) and two in the C-terminal end of gp70 (aa 418, CH2; aa 326, CH3) were inactive. These results, taken together with other data from our laboratory and others, suggest that the entire gp70/p15E structure is sensitive to alterations and that even envelope proteins that are very similar have only a limited ability to exchange sequences.

3T3 Cells↗
PubMed1995

Chiari's network: normal anatomic variant or risk factor for arterial embolic events?

OBJECTIVES: This study was performed to assess the prevalence of Chiari's network in patients undergoing transesophageal echocardiography and to determine whether this anomaly is associated with other cardiac lesions or is characterized by typical clinical findings. BACKGROUND: Chiari's network is a congenital remnant of the right valve of the sinus venosus. It has been found in 1.3% to 4% of autopsy studies and is believed to be of little clinical consequence. METHODS: Video recordings of 1,436 consecutive adult patients evaluated by transesophageal echocardiography over a 30-month period were reviewed for the presence of Chiari's network. Echocardiographic contrast studies had been performed in all patients with Chiari's network and were compared with those of 160 consecutive patients without a Chiari net, serving as a control group. RESULTS: Chiari's network was present in 29 of 1,436 patients (prevalence 2%). A frequently associated finding was a patent foramen ovale in 24 (83%) of the 29 patients with Chiari's network versus 44 (28%) of 160 control patients (p < 0.001). Intense right-to-left shunting occurred significantly more often in patients with Chiari's network than in control patients (16 [55%] of 29 patients vs. 19 [12%] of 160 control patients, p < 0.001). Another frequent association was an atrial septal aneurysm in 7 (24%) of 29 patients. The indication for transesophageal echocardiography was a suspected cardiac source of arterial embolism in 24 (83%) of 29 patients with a Chiari net, 13 of whom (54%) had recurrent embolic events. Chiari's network was significantly more common in patients with unexplained arterial embolism than in patients evaluated for other indications (24 [4.6%] of 522 patients vs. 5 [0.5%] of 914 patients, p < 0.001). Potential causes for arterial embolism were present in 9 of the 24 patients with a Chiari net and embolic events (atrial septal aneurysm in 7, cerebrovascular lesion in 2). In 15 (62%) of 24 patients only a patent foramen ovale could be identified. Three patients had deep venous thrombosis and pulmonary embolism at the time of arterial embolism; none had a thrombus detected within the network. CONCLUSIONS: In patients undergoing transesophageal echocardiography, the prevalence of Chiari's network was 2%, which is consistent with autopsy studies. By maintaining an embryonic right atrial flow pattern into adult life and directing the blood from the inferior vena cava preferentially toward the interatrial septum, Chiari's network may favor persistence of a patent foramen ovale and formation of an atrial septal aneurysm and facilitate paradoxic embolism.

Abnormalities, Multiple↗
PubMed1995

Simultaneous measurement of pulmonary venous flow by intravascular catheter Doppler velocimetry and transesophageal Doppler echocardiography: relation to left atrial pressure and left atrial and left ventricular function.

OBJECTIVES: The aim of our study was to compare measurements of pulmonary venous flow velocity obtained either by transesophageal Doppler echocardiography or by intravascular catheter Doppler velocimetry. Furthermore, the relation among pulmonary venous flow velocity, left atrial compliance and left atrial pressure was evaluated. BACKGROUND: Data about the relation between left atrial pressure and pulmonary venous flow velocity are controversial. METHODS: A total of 32 patients undergoing elective open heart surgery for coronary artery bypass grafting were included prospectively in the study. Pulmonary venous flow velocity (Doppler catheter) and left atrial pressure (microtip pressure transducer) were recorded simultaneously with recordings of pulmonary venous flow velocity obtained by transesophageal Doppler echocardiography. RESULTS: Agreement between Doppler catheter and Doppler echocardiographic measurements of pulmonary venous flow velocity (n = 18 patients) was analyzed using the Bland-Altmann technique. The 95% limits of agreement were -0.16 to +0.11 m/s for systolic peak velocity, -0.14 to +0.09 m/s for diastolic peak velocity and -0.12 to +0.10 m/s for atrial peak velocity. The closest agreement between both methods was found for the ratio of systolic to diastolic peak velocity, the ratio of systolic to diastolic flow duration and the time from Q deflection on the electrocardiogram to maximal flow velocity. Mean left atrial pressure was strongly correlated with the ratio of systolic to diastolic peak velocity (r = -0.829), systolic velocity-time integral (r = -0.653), time to maximal flow velocity (r = 0.844) and the ratio of systolic to diastolic flow duration (r = -0.556). The ratio of systolic to diastolic peak velocity and the time to maximal flow velocity were identified as strong independent predictors of mean left atrial pressure. Left atrial compliance was not found to be an independent predictor of mean left atrial pressure. CONCLUSIONS: Flow velocity in the left upper pulmonary vein can be reliably recorded by transesophageal pulsed wave Doppler echocardiography. Our data reveal further evidence that mean left atrial pressure can be estimated by the pattern of pulmonary venous flow velocity.

Aged↗
PubMed1995

[In vitro studies of the effect of vasoconstrictor nose drops on ciliary epithelium of human nasal mucosa].

We investigated the influence of four nasal decongestants and one preservative on ciliated cells, using cell cultures of human nasal mucosa. These cells were exposed to nasal decongestants in vitro. A fast decrease in ciliary beat frequency was seen during naphazoline and oxymethazoline application which was fully reversible after naphazoline. There was only a minimal decrease in ciliary beat frequency during application of phenylephrine and xylomethazoline decongestants. The preservative benzalkoniumchloride caused an irreversible decrease in ciliary beat frequency which was concentration dependent. We therefore recommend nasal decongestants which contain xylomethazoline or phenylephrine. If the preservative benzalkoniumchloride can not be substituted by newer less harmful substances, it should be added in minimal concentrations.

Dose-Response Relationship, Drug↗