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Biomedical subjects

G Lenz

Publications and source records attributed to G Lenz.

At least 73 records · Page 4Linked to original sources
PubMed1993

Highly acute course of ruptured papillary muscle of the tricuspid valve in a case of blunt chest trauma.

The sudden onset of tricuspid insufficiency following a blunt chest trauma is extremely rare. We operated on a young woman in a state of severe shock following a riding accident, in whom complete severing of the papillary muscle of the posterior tricuspid leaflet had occurred. The valvuloplasty operation itself and the postoperative course ran smoothly, apart from a late pericardial tamponade which required surgical revision. In accordance with other reported cases we believe that traumatic tricuspid insufficiency is still a very underestimated pathological occurrence. Echocardiographic examination should therefore be regarded as an essential standard procedure in all cases of blunt chest injury.

Acute Disease↗
PubMed1993

[Monitoring neuromuscular function: capnography versus relaxometry].

OBJECTIVE: A notch ("curare cleft") in the plateau phase of the capnogram of the ventilated patient has been presumed to be a typical early sign of the fading effect of muscle relaxants on the diaphragm. For that reason a prospective study was done to investigate whether capnography can be used diagnostically to indicate the fading effect of vecuronium confirmed by peripheral relaxometry. METHODS: Twenty-five consecutive patients who received inhalation anaesthesia with isoflurane, N2O/O2, and vecuronium during elective neurosurgical procedures were studied. Whenever intraoperative "curare clefts" appeared in the capnogram, diaphragm activity was measured and a simultaneous relaxogram of the adductor pollicis muscle was recorded. After every such event, vecuronium was readministered for complete relaxation. RESULTS: A deformation of the capnogram was registered in 17/25 patients and in all instances (51/51) was caused by diaphragm activity. The deformation disappeared after renewed relaxation and was therefore a reliable indicator of spontaneous breathing. However, it did not correlate with the degree of relaxation of peripheral muscles, because diaphragm activity was present during all degrees of peripheral relaxation, but could also be absent even after complete recovery of neuromuscular transmission. CONCLUSION: Capnography is therefore not a reliable method to indicate the fading effect of muscle relaxants.

Anesthesia, Inhalation↗
PubMed1993

Obsessive-compulsive disorder and depression. A retrospective study on course and interaction.

In a retrospective study 62 patients, who fulfilled the ICD-8/9 criteria for obsessive-compulsive disorder (OCD), were followed up. Besides an assessment of the cross-sectional symptomatology of OCD and depression, the long-term course of OCD and its relationship to depression were investigated. Five courses of OCD could be differentiated: continuous and unchanging (27.4%); continuous with deterioration (9.7%); continuous with improvement (24.4%); episodic with partial remission (24.2%), and episodic with full remission (11.3%). There was no difference between primary or secondary depression on the prognosis of OCD, and there was also no difference between the continuous or episodic course with regard to primary or secondary depression. Our results may be biased by the fact that we selected a sample of OCD and not primarily major depressive patients.

Adult↗
PubMed1992

Breath-hold T2-weighted sequences of the liver: a comparison of four techniques at 1.0 and 1.5 T.

T2-weighted images are considered the most sensitive for lesion detection at high field; however, long imaging time is problematic. Accordingly, the authors compared four breath-hold T2 or T2* weighted sequences comprising T2*-weighted FLASH, T2*-weighted PSIF, T2-weighted rapid spin echo (RASE), and T2-weighted Turbo-FLASH (Turbo) in 20 different healthy volunteers, 10 at 1.0 T and 10 at 1.5 T with reference to regular T2-weighted spin echo. Images were evaluated quantitatively by liver signal to noise (S/N) and spleen-liver signal difference to noise (SD/N) ratios and qualitatively for presence of artifacts and image quality. Data were evaluated for 1.0 T and 1.5 T separately and combined. In the combined evaluation, T2*-FLASH had good S/N (23.1 + 5.1) but low SD/N (2.9 + 1.7) and suffered from susceptibility artifacts. T2* PSIF had good S/N (28.1 + 10.0) and moderate SD/N (6.0 + 2.4), but occasionally had heterogeneous signal intensity. Flow signal void was an attractive feature. T2 RASE had very low S/N (4.4 + 1.9) and low SD/N (2.3 + 1.1) and suffered from flow artifacts. T2-Turbo had good S/N (24.6 + 8.6) and SD/N (8.9 + 2.5). Flow signal void was present, but small matrix size decreased image quality. The results of our study suggest that T2*-PSIF and T2-Turbo have good S/N and SD/N and fair image quality which may be clinically useful for breath-hold T2-weighted sequences of the liver.

Adult↗
PubMed1992

The effect of long-term lithium treatment on the mortality of patients with manic-depressive and schizoaffective illness.

Clinical research centers in Aarhus, Berlin, Hamilton and Vienna collected mortality data for 827 manic-depressive and schizoaffective patients given lithium treatment for more than 6 months. The average duration of the treatment was 81 months and the total time on lithium 5600 patient-years. For each patient, the mortality risk was calculated by entering the appropriate national life tables for the general population. The number of observed deaths was 44; the number of expected deaths was 49.7. The standardized mortality ratio, 0.89, did not differ significantly from 1.0. The mortality of manic-depressive patients is 2-3 times that of the general population. Our data show that the mortality of manic-depressive and schizoaffective patients given long-term lithium treatment does not differ significantly from that of the general population.

Adult↗
PubMed1991

Capnometry for continuous postoperative monitoring of nonintubated, spontaneously breathing patients.

We continuously monitored spontaneous respiration after extubation by end-tidal CO2 tension (PETCO2) in 19 patients aged 20 to 72 years who had undergone major operations. The respiratory gas was sampled from the nasopharynx via a special nasal catheter and analyzed by a side-stream analyzer. In each case, optimal placement of the nasal catheter was determined by CO2 waveform and the capnograms were recorded for waveform analysis and trend monitoring. PETCO2 was compared with arterial CO2 tension (PaCO2) two to four times during the 2- to 19-hour observation periods by simultaneous measurements. For 65 simultaneous measurements, mean PETCO2 was 38.9 +/- 5.7 mm Hg (range, 26.3 to 48.3 mm Hg) and mean PaCO2 was 38.9 +/- 5.7 mm Hg (range, 26.8 to 46.0 mm Hg; r = 0.82; p less than 0.01). While the mean values for PETCO2 and PaCO2 were similar, several patients had large differences for PaCO2 to PETCO2. The differences of the individual patients did not differ significantly between the various times of measurement. We conclude that this form of capnometry is well suited for continuous, noninvasive monitoring of respiration in nonintubated, spontaneously breathing patients.

Adult↗
PubMed1991

T1-weighted sequences for MR imaging of the liver: comparison of three techniques for single-breath, whole-volume acquisition at 1.0 and 1.5 T.

The authors compared three T1-weighted magnetic resonance imaging techniques that acquire images encompassing the entire liver in one breath hold. Twenty healthy volunteers were imaged--10 at 1.0 T and 10 at 1.5 T--and the results compared with those of regular short repetition time/echo time spin-echo imaging. Rapid acquisition spin echo was resistant to artifacts and had good image quality but had the lowest liver signal-to-noise (S/N) and spleen-liver signal-difference-to-noise (SD/N) values. Fast low-angle shot (FLASH) had the highest S/N and SD/N, very good image quality, and only mild artifacts. TurboFLASH had good S/N and SD/N, but reduced matrix size decreased image quality. All three sequences had better SD/N than regular spin echo, and FLASH and TurboFLASH had higher S/N. On the basis of this study, the FLASH sequence appears the most attractive for T1-weighted breath-hold imaging.

Adult↗
PubMed1991

Temporal stability of diagnostic criteria for functional psychoses. Results from the Vienna follow-up study.

200 first admissions with functional psychoses were interviewed with PSE and rated simultaneously according to different diagnostic criteria (ICD-9, RDC, DSM-III, St. Louis, Taylor, Vienna Research Criteria). At follow-up 7 years later 186 patients could be traced and a course diagnosis was applied to each patient. Temporal stability of diagnostic criteria was calculated for ICD-9, RDC and DSM-III by stability coefficient and kappa values and was used as a criterion for validity. Schizophrenia and affective disorder display considerable stability over time, no matter whether one uses ICD-9, RDC or DSM-III. The data for schizoaffective disorder are less impressive, the stability coefficient is much higher for schizoaffective bipolar than for schizoaffective depressive patients.

Family↗
PubMed1991

Elimination of pyridoxylated polyhemoglobin after partial exchange transfusion in chimpanzees.

Partial exchange transfusion with 8.5% pyridoxylated polyhemoglobin solution [PolyHb-PPa] was performed in five male chimpanzees weighing 22-30 kg. Serial blood and urine samples were obtained for 3 days. Percutaneous liver biopsies were performed on the 3rd to 4th, and the 9th to 11th days after PolyHb-PPa administration. Mean exchange volume was 42.5 +/- 10.7 ml/kg BW (26.8-54.6 ml/kg), mean Hb dose 3.7 +/- 0.9 g PolyHb-PPa/kg BW (2.4-4.8 g/kg), mean exchange rate 56.7 +/- 7.1% (48.2-67.4%). All animals survived long-term. Analysis of the plasma Hb concentration-time data showed a first order decline at a plasma level of 3.7 +/- 0.9 g PolyHb-PPa/kg BW. Mean intravascular half-life was 14.6 +/- 3.2 h. Total renal elimination of PolyHb-PPa was about 7%. PolyHb-PPa was absorbed and stored by Kupffer cells and transformed into hemosiderin. Siderosis of Kupffer cells and renal tubules had largely subsided 10 days after PolyHb-PPa indicating subsequent in vivo degradation and metabolization of the polymerized Hb fractions.

Animals↗
PubMed1991

Hemodynamic effects after partial exchange transfusion with pyridoxylated polyhemoglobin in chimpanzees.

Partial exchange transfusion with 8.5% pyridoxylated polyhemoglobin solution [PolyHb-PPa] was performed in five anesthetized spontaneously-breathing male chimpanzees weighing 22-30 kg. Mean exchange volume was 42.5 +/- 10.7 ml/kg BW (26.8-54.6 ml/kg), mean exchange rate 56.7 +/- 7.1% (48.2-67.4%). All animals survived long-term. The chimpanzee's hemodynamics remained stable for the 5 h observation period. Right and left ventricular filling pressures remained constant, mean arterial pressure and mean pulmonary arterial pressure increased by up to 40% after the exchange. Cardiac output remained unaffected by the partial exchange and stroke volume did not change substantially although oxygen capacity and oxygen transport capacity decreased by about a third. The failure of cardiac output to rise after partial exchange transfusion with PolyHb-PPa contrasts with results after isovolemic hemodilution using non-oxygen-carrying blood substitutes and is not adequately explained by the oxygen capacity of 8.5% PolyHb-PPa (9.3 ml O2/dl).

Animals↗