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Biomedical subjects

K Seitz

Publications and source records attributed to K Seitz.

At least 55 records · Page 3Linked to original sources
PubMed1997

DREZ coagulations for deafferentation pain related to spinal and peripheral nerve lesions: indication and results of 79 consecutive procedures.

During a 16 years' period, a total of 79 dorsal root entry zone coagulations were performed in 68 patients for deafferentation pain. Of the 23 patients who underwent surgery for pain due to cervical root avulsion, 18 (82%) had a good (12) or fair (6) pain relief (mean follow-up period 51 months). Twelve (57%) patients with spinal cord injuries noted continuous pain reduction (10 good, 2 fair; mean follow-up 52 months). Continuous marked improvement for longer periods was reported only by 2 out of 10 patients with postherpetic neuralgia and 1 out of 7 patients with painful states due to other brachial plexus lesions and none out of 5 with spinal cord lesions (3) and phantom limb pain (2).

Adult↗
PubMed1995

[Portal hypertension--current status of ultrasound diagnosis].

Splenomegaly, ascites, and anatomy of intra- and extrahepatic portal vessels can reliably be detected by ultrasound in case of portal hypertension. The increased diameter of the portal vein and its roots is a not sufficient sensitive and specific finding in portal hypertension. However a marked variation of diameter at the superior mesenteric vein during in- and expiration is nearly exclusive. With the help of colour flow imaging or duplex sonography additional finding of blood flow in the portal system can be detected noninvasively and continuously. Quantitative blood-flow measurement in routine examinations is unnecessary and reserved to special questions. Reverse flow or significantly decreased blood flow velocity or the detection of portocaval collaterals are reliable findings in portal hypertension. In addition thrombosis of portal vessels and its hemodynamic consequences can be seen. Because underlying diseases e.g. liver cirrhosis or tumours are diagnosed in the same procedure ultrasound techniques are used in first line when portal hypertension is suspected. The findings are complementary to endoscopy of upper g.i.tract and lead on the one hand to a well-aimed use of CT scanning or x-ray splenoportography, and--on the other hand--make them dispensable in a low of cases.

Blood Flow Velocity↗
PubMed1995

[Effects of presentation mode on visual-spatial working memory performance in children and adults].

We report two studies investigating the effects of several experimental manipulations on visuo-spatial memory performance in children and adults. In particular, we were interested in memory for the location of objects. A picture reconstruction task was used where picture-like arrangements of four to six items were briefly presented and then reconstructed. In the first experiment with 5- and 8-year-olds and adults, the degree of visual differentiation of the items as well as presentation mode (simultaneous versus serial) were varied. Contrary to our hypothesis, there was a negative effect of simultaneous presentation in children, but only if the degree of visual differentiation was low. There was no such effect in adults. In a second experiment with 6- and 8-year-olds and adults, we again varied presentation mode, but excluded the scene-like character of the arrangements. All the age groups were slightly better with serial presentation. However, reducing the available schematic knowledge led to a severe performance decrease. The results are related to the current discussion about a further fractionation of the VSSP and to different assumptions about internal representations of location information.

Adolescent↗
PubMed1993

[Ultrasound diagnosis of hepatocellular carcinoma].

From 1983 to 1992 we found in 50 patients a hepatocellular carcinoma (HCC). The diagnosis was confirmed by histology (n = 34), cytology (n = 4) or clinical symptoms together with ultrasound findings and laboratory signs. 41 of the tumors occurred in cirrhotic livers. 29 patients had singular tumors, 21 had multiple tumors or diffuse tumor spreading in the whole liver. The singular tumors ranged in size from 1.1 to 15 cm. 8 of these tumors were smaller than 3 cm in diameter. The sonomorphological tumor pattern was hyperechoic in 24 cases, 14 of them had a halo sign. 14 tumors were hypoechoic. In the 12 cases with a mixed sonomorphologic pattern, a mosaic of hyperechoic and hypoechoic areas seemed to be very characteristic. Biopsies of the different parts of such a tumor in 1 patient showed different degrees of fat. By color Doppler-sonography, in 8 of 12 investigated patients an increased tumor perfusion was detected. In conclusion, HCC has different sonomorphologic patterns. The so-called mosaic pattern is characteristic, but rare. A focal lesion in a cirrhotic liver is highly suspicious for HCC. Ultrasound is effective as a screening method for risk groups with liver cirrhosis, hemochromatosis or chronic hepatitis.

Adult↗
PubMed1991

[Sonographic imaging of lung emboli. Results of a prospective study].

UNLABELLED: From 8/90 to 9/91 the lungs of 100 consecutive patients (35 male, 65 female) were examined sonographically. INDICATIONS: 1. tentative diagnosis of pulmonary embolism by clinical signs (n = 47) 2. only chest pain in breathing (n = 32), 3. deep vein thrombosis without signs of pulmonary embolism (n = 21). In 67 cases perfusion lung scans ware available. The typical sonographic sign is a wedge-shaped echo-poor lesion with or without a local effusion. In the first group, both methods coincided positively in 28 cases, whereas only the scan detected pulmonary embolism in 6 cases. In the second group, 8 cases were found by ultrasound, only 3 by scan. 6 patients from the third group showed pulmonary embolism sonographically. Multiple pulmonary embolism can be shown by both methods in a comparable percentage. False negative findings by ultrasound are to be expected in perfusion lesions of nearly one lobe of the lung or more, whereas contrariwise small signal embolism causes more often negative scans. Ultrasound is a additional, easily available and even alternative method of detecting pulmonary embolism, especially in case of doubt or if lung scan is not feasible.

Adolescent↗
PubMed1991

[Duplex ultrasound measurement of blood flow in the superior mesenteric artery].

After a successful check of a duplex sonographic instrument in a water-bath, the following parameters were measured under standardised conditions in 30 fasting patients: blood flow rate in the mesenterica superior artery, maximal systolic, end-diastolic and average velocity as well as the vessel diameter. From these data the average blood flow rate was calculated. Maximal systolic velocity is on the average 134 +/- 22.8 cm/s, end diastolic 20.8 +/- 4.4 cm/s, average vascular diameter 7.6 +/- 0.7 mm, median blood flow 639 +/- 153 ml/min. Day-to-day variance is for the maximum systolic velocity at 11%, for end diastolic velocity at 9.7% and for the average vascular diameter at 2.2%. Postprandially the average flow velocity increases from 23.4 +/- 5.6 to 46 +/- 7.4 cm/s. The average vascular diameter increases from 7.6 +/- 0.7 to 8.0 +/- 0.8 mm. The median blood flow increases one hour after a non-standardised lunch by 126%. To show that Duplex sonography also covers pharmacodynamic blood flow changes, the maximum systolic, maximum diastolic and average velocity was measured before and 1 hour after ingestion of 20 mg nifedipine in 5 subjects. The measured parameters showed a significant increase.

Adolescent↗
PubMed1990

Differences between atrial single chamber pacing (AAI) and ventricular single chamber pacing (VVI) with respect to prognosis and antiarrhythmic effect in patients with sick sinus syndrome.

Several studies suggest different effects of atrial (AAI) and ventricular single chamber pacing (VVI) for sick sinus syndrome with respect to the suppression of atrial tachycardias and to the prognosis. With this aspect in mind, we studied 222 patients with sick sinus syndrome, 110 of whom had been supplied with AAI systems, and 112 with VVI systems, in the period from January 1978 to December 1986. The mean observation period was 53 +/- 28 months. The cumulative 5-year survival rate was not significantly different in the two groups. After subgroups with comparable underlying diseases had been differentiated, patients with coronary heart disease showed a significantly higher survival rate (P less than 0.05) under AAI pacing, and the same was shown for patients with no underlying heart disease (P less than 0.02). The incidence of chronic atrial fibrillation was 6% in the AAI group and 19% in the VVI group. Patients with preexisting atrial tachyarrhythmias showed the lowest incidence of chronic atrial fibrillation under AAI pacing. Under VVI pacing this incidence was a function of the basic rate of the pacemaker systems. In conclusion, the pacing mode seems to have a prognostic importance in spite of all methodological difficulties. A suppressive effect of AAI pacing on atrial dysrhythmias can also be assumed.

Aged↗
PubMed1989

[Sonographic diagnosis of hepatocellular carcinoma. Results of a retrospective study 1983-1989].

In a retrospective study of our hospital of the years 1983 to 1989 we diagnosed a hepatocellular carcinoma (HCC) in 30 patients. The diagnosis was confirmed by histology or cytology, ultrasound and clinical symptoms. The tumours presented sonomorphologically different patterns. Some were hypoechoic (n = 9), some hyperechoic (n = 16) and 5 had a mixed pattern. Nine of the hyperchoic lesions looked like a metastasis with a halo. 13 patients had multiple tumours or diffuse infiltration of the liver. Due to the variable sonomorphology only 16 patients were assumed to have a HCC, no definite diagnosis by ultrasound being possible. The concomitant cirrhosis of the liver was sonomorphically detected in 19 patients and was suspected in 2 further patients. Four patients had no cirrhosis; in 3 patients, the available information was insufficient. Because of the variable sonomorphology of HCC no definite diagnosis by ultrasound can be achieved. The combination of liver tumour and cirrhosis or elevated serumfetoprotein leads to the diagnosis. The diagnosis of HCC must be confirmed by histology.

Aged↗
PubMed1989

[Sonographic diagnosis of choledochus cysts].

Patients suffering from choledochus cysts are rare among the patients of a District Hospital. We found only four choledochus cysts among about 70,000 sonographies performed during the past ten years, all of them in young women. These patients show sonographically a liquid space-occupying lesion in the hepatic porta next to the gallbladder. To safeguard the sonographic diagnosis an ERC or an i.v. cholangiogram should always be performed preoperatively. Operative removal should always be aimed at because of chronic recurring cholangitis and the relatively high risk of malignancy in the future.

Adolescent↗
PubMed1989

[Sonographic-controlled puncture and its effect on further diagnosis and therapy].

Results of 127 sonographically guided punctures performed during 1982 to 1987 were evaluated retrospectively and the results of coarse needle and fine needle punctures were compared. In 74 punctured focal liver changes the superiority of coarse needle biopsy was particularly evident whenever a definitive histological confirmation of the diagnosis is aimed at. No therapy was initiated in 82 of the 127 patients after the biopsy finding had been established, and surgery was performed in 22 cases. 18 patients were given cytostatic treatment, and tumour embolisation was performed twice. 3 patients with non-malignant disease were successfully treated conservatively in pancreatic abscess, intraabdominal tuberculosis and actinomycosis.

Adenoma, Bile Duct↗
PubMed1989

[Routine sonography in suspected appendicitis. A trial of 24-hour screening at a general hospital].

A prospective study was conducted to determine the diagnostic value of sonography in suspected acute appendicitis. From September 1987 until May 1988, the end of the study, 152 patients suspected of having "acute appendicitis" were admitted to hospital. In contrast to other recently published studies conducted by a few highly qualified examiners, we dimed at determining whether this method is useful as a 24-hour-screening performed ba y number of more or less qualified examiners. In the beginning, the patients were examined with a 3.5 MHz scanner, later on exclusively with 5 MHz linear and sector scanners. 150 cases could be evaluated, 96 of which underwent surgery. We found 35 sonographically correct results, 89 correctly negative, 4 false positive and 13 false negative diagnoses. This means a sensitivity of 73% and a specificity of 96% for the sonographical diagnostic method. In 20 cases (13%) sonography led to other diagnoses. A large majority of these findings can be detected by less experienced examiners. The goal of a 24-hour-screening could not be reached because there a competent examiner was not always available at night. It became clear that clinically obvious cases do not require sonographic conformation. The value of sonography lies with doubtful cases of appendicitis: if the ultrasound examination is negative, appendectomy can be postponed; if sonography leads to other differential diagnoses, appropriate therapy can be started immediately.

Adolescent↗
PubMed1989

[Clinical use of duplex sonography of the abdomen].

The clinical use of the duplex methods in the abdominal space is at present partly based on case study and partly systematic. Established ranges of application exist for the portal circulation and the kidney transplant. This method enables for the first time a noninvasive diagnosis of mesenterial disturbances of blood flow. The future of the method in the abdominal space will be mainly determined by continued technical development and results of practical clinical application. Results achieved so far lead us to expect that the Duplex methods are a valuable addition to the sonographic palette.

Abdomen↗
PubMed1989

[Thromboses of the subclavian vein and jugular vein and superior vena cava: sonographic diagnosis and control of treatment using tissue-type plasminogen activator therapy].

In the suspected diagnosis "superior influx congestion" sonography performed with the 5 MHz linear scanner is suitable as a non-invasive method for the primary diagnosis of thrombotic occlusions of the vena subclavia and vena jugularis interna, and for follow-up monitoring under thrombolytic therapy. In successful lysis it is possible to verify a sonomorphological and Doppler sonographic sequence of stages from the freshly formed, stratified stage via the high-echo to the low-echo thrombus with formation of lacunae, as well as the recanalisation that is seen at first only at the margins and eventually becomes complete with a flow that varies with the respiration.

Female↗
PubMed1989

[Initial clinical experiences with mechanical heart stimulation].

Rhythmical extrathoracic mechanical stimulation can produce cardiac systoles. The study was designed to determine the usefulness of this procedure in bridging the time gap between the occurrence of asystole or symptomatic bradycardia and the beginning of temporary cardiac pacing or the restoration of a sufficiently high spontaneous heart rate. The mechanical stimulator was used on 31 patients. In 10 patients sufficient circulation with palpable pulse in the femoral artery could be restored. Five patients needed temporary electrical pacing. Five of the patients successfully treated mechanically died within 24h of terminal circulatory collapse or electromechanical dissociation. Five patients could be dismissed from hospital, with only one of them needing permanent cardiac pacing. Twenty of the 21 patients who could not be stimulated mechanically died. Seventeen of those showed electromechanical dissociation when treated with transvenous endocardiac stimulation, three suffered from terminal circulatory collapse. In one patient with an instable thorax sufficient circulation could be obtained by extrathoracic mechanical stimulation. Four patients were not stimulated electrically because of old age and polymorbidity. Problems in using the extrathoracic mechanical stimulation are discussed and compared with endocardiac and extrathoracic electrical stimulation.

Aged↗
PubMed1988

Influence of AV synchrony on the plasma levels of atrial natriuretic peptide (ANP) in patients with total AV block.

ANP was determined in 13 patients with DDD pacemakers due to total AV block, at rest and during bicycle ergometry under both pacing modes, DDD and VVI (7O/min). Under DDD pacing, the mean ANP level (normal range 5-95 pg/mL) at rest was 36 +/- 18 pg/mL (mean +/- SD) and increased significantly by the factor of 3.5 to 1 27 pg/mL during exercise (p less than 0.01). By just changing the pacing mode to VVI, the ANP levels rose to 73 +/- 28 pg/mL (p less than O.0 1) at rest (= 203% of DDD resting level) and to 216 +/- 184 pg/mL (= 170% of DDD peak level) during exercise P less than 0.01). These results show that under AV synchronous pacing, the ANP levels we generally lower. A possible explanation for this increased release of ANP during asynchronous VVI pacing is the acute increase of the atrial wall tension which occurs when the atria contacts during the systole against closed AV valves.

Aged↗
PubMed1988

A new multisensor pacing system using stroke volume, respiratory rate, mixed venous oxygen saturation, and temperature, right atrial pressure, right ventricular pressure, and dP/dt.

A new multisensor pacing device using respiratory rate (RR), stroke volume (SV), oxygen saturation (SO2), temperature (T), right atrial pressure (RAP), right ventricular pressure (RVP) and right ventricular dP/dt, has been developed. It consists of a 7F multisensor catheter and an external pacing unit. It allows simultaneous recording of the input signals and the corresponding data can be compared among the different parameters under identical conditions. Furthermore, several parameters can be combined in such a way as to form a new combination better suitable for rate responsive pacing. The response of each parameter to exercise was studied in 12 healthy volunteers (mean age: 28 years). Exercise testing was carried out using a bicycle ergometer, with workloads up to 200 W. The dynamic characteristics, response and sensitivity to changes of workloads of each parameter were analyzed and compared to one another. SO2 proved to be a quick responding parameter (less than 10 sec) with higher sensitivity in the low exercise range (less than 75 W), T, on the other hand, responded slowly (greater than 30 sec) to exercise changes and had the highest sensitivity in the exercise range beyond 75 W. RR displayed a slow response (greater than 30 sec) and an adequate sensitivity was only found in the upper exercise range (greater than 100 W). SV reacted rapidly to workload changes (less than 10 sec) but showed poor sensitivity at all exercise levels. RAP, RVP and dP/dt displayed quick responses and constantly good sensitivity throughout the workload range. Furthermore, respiratory rate was easily derived from the RAP curve. Special algorithms were developed for each parameter so that pacing rate would reproduce sinus rate behavior. We found that SO2 and all pressure parameter imitated sinus rate response quite well. When using parameter combinations, SO2 and T proved to be superior. Five patients (mean age 68 years) with third degree AV-block were stimulated temporarily using this system. Compared to fixed rate stimulation (VVI 70), exercise performance improved, using SO2 as the input parameter for rate response, by 25% to 50%.

Adult↗