Biomedical subjects

K Haag

Publications and source records attributed to K Haag.

59 records · Page 4Linked to original sources

PubMed1984

Determination of short-circuit current in the in vivo perfused rat colon.

Current pulses (I) were injected into the lumen of proximal colonic segments in vivo, and the corresponding voltage deflections (delta PD) superimposed on the transcolonic PD were recorded. From the exponential decay of delta PD along the colon axis, the electrical length constant (lambda) was determined. Based on cable analysis the input resistance (= delta PD x = 0/I) and lambda made it possible to calculate the specific resistance (Rm) of the colonic epithelium as 128 +/- 16 omega X cm2. As Rm proved to be an ohmic resistor, the extrapolation from open-circuit PD (8-12 mV, lumen negative) to zero PD was feasible and made the calculation of short-circuit current (= PD/Rm) equal to 70 +/- 16 microA/cm2. In the presence of amiloride short-circuit current decreased to about 50%, whereas with theophylline it increased by about 30%. Substitution of luminal Na+ with choline or Cl- with cyclamate was associated with a marked increase of Rm. The rheogenic component of net Na+ transport was estimated to be only 8%. Electroneutral Na+ absorption functionally coupled with Cl- absorption displayed the characteristic feature of ion transport in the rat proximal colon.

Animals↗

PubMed1984

Qualitative and quantitative gait phase analysis by continuous monitoring of inter-ankle distance.

A new device is presented that is able to provide a temporal recording of gait as well as a continuous qualitative monitoring of gait events. It can be used with motor-point electromyography to perform walking electromyography, with an electrogoniometer to record joint position, or with other measuring devices to record events relative to phase of gait. The major advantages of this system as compared with available systems are ease of use, decreased patient encumbrance, potential for portability, greatly reduced expense, and the potential for digitizing the signal for computer compatibility. Preliminary data are comparable to available accepted norms.

Adult↗

PubMedDate not supplied

Morphologic and clinical results of the transjugular intrahepatic portosystemic stent-shunt (TIPSS).

The concept of transjugular intrahepatic portosystemic stent-assisted shunt (TIPSS) using the Palmaz iliac stent has been successfully accomplished in 18 of 24 patients representing a technical success rate of 75%. Fourteen were male, 4 female with a mean age of 60 years (range 34-84 years). According to classification of Child's and Turcotte, 6 were in stage A, 6 in stage B, and 6 in stage C. Five patients were treated on an emergency basis because of massive active bleeding. In 10 patients the portosystemic tract was created between the middle hepatic vein and the right main stem of the portal vein in 8, and the left main stem in 2 patients. In 8 patients, the shunt was established between the right hepatic vein and the right main branch of the portal vein. The portosystemic gradient in 18 patients was 29.9 +/- 6 mm Hg and dropped to an average of 16.9 +/- 4 mm Hg after shunt establishment. Within the early postprocedural period of 30 days, 1 patient died of direct complications of the procedure. Because of catheter dislocation, embolization of the percutaneous transhepatic approach to the portal vein after successful shunt "creation" could not be done and was followed by intraabdominal exsanguination. One patient died of an ARDS after TIPSS. A third developed pulmonary infection. In 13 patients, because of hematomas at the puncture site of the transhepatic approach, only the transjugular approach was elected for establishing TIPSS.(ABSTRACT TRUNCATED AT 250 WORDS)

Equipment Design↗

PubMedDate not supplied

Helicobacter pylori infection does not correlate with plasma ammonia concentration and hepatic encephalopathy in patients with cirrhosis.

BACKGROUND/AIMS: In patients with cirrhosis, infection of the stomach with Helicobacter pylori may increase ammonia production and, consequently, the incidence of hepatic encephalopathy. To test this hypothesis a retrospective analysis was performed in patients with a transjugular intrahepatic portosystemic shunt. These patients are regarded to be ideal candidates for such a study since they have a high bioavailability of gut-derived ammonia and many of them develop spontaneous hepatic encephalopathy. METHODOLOGY: In 132 patients (Child-Pugh class A: 24%, B: 49%, C: 27%) with stable transjugular intrahepatic portosystemic shunt function for more than 3 months (mean follow-up: 15.5 +/- 10.8 months) the diagnosis of H. pylori infection was established by a specific and sensitive immunoblot assay for IgG- and IgA-antibodies. During follow-up, hepatic encephalopathy was assessed by clinical examination and a structured questionnaire. Venous plasma ammonia concentration was measured at the time of antibody determination (end of study period). RESULTS: Eighty-four patients (64%) had negative and 48 patients (36%) had positive immunoblots for H. pylori. The groups were comparable with respect to age, gender, etiology of cirrhosis, Child-Pugh class, follow-up after transjugular intrahepatic portosystemic shunt, and shunt function. The ammonia concentrations of the patients without (group 1) and with antibodies against H. pylori (group 2) were 73 +/- 27 and 69 +/- 28 mumol/L (mean +/- SD), respectively. Hepatic encephalopathy occurred in 23 of 84 patients (27%) of group 1 and in 11 of 48 patients (23%) of group 2. CONCLUSIONS: A positive immunoblot for H. pylori antibodies neither correlates with plasma ammonia concentration nor with the incidence of hepatic encephalopathy in patients with cirrhosis of the liver and portosystemic shunt.

Adult↗

PubMedDate not supplied

No evidence for abnormal gallbladder emptying in Crohn's disease.

BACKGROUND/AIMS: An increased risk of gallstone development has been found in patients with Crohn's disease. This has been suggested to be due to abnormal bile acid metabolism. We investigated the possibility that Crohn's disease might alter gallbladder mechanical function and predispose to gallstone formation by incomplete emptying or prolonged contraction time of the gallbladder. MATERIALS AND METHODS: Seventeen patients with Crohn's disease (CD) and 20 healthy controls (CO) of similar age and sex (CD: 7 males, 31 +/- 13 years; 10 females, 30 +/- 9; CO: 10 males, 26 +/- 12; 10 females, 26 +/- 9) were compared. None of the patients or controls had gallstones. Using ultrasonography with computed volume calculation, the gallbladder was assessed in fasting state and every 10 min for 70 minutes after ingestion of a standard fatty meal. RESULTS: Neither maximum volume (CD: 22 +/- 9 ml, CO: 25 +/- 15), residual volume after stimulation (CD: 3 +/- 2 ml, CO: 6 +/- 6 ml), volume decrease in % (CD: 83 +/- 5%, CO: 78 +/- 9%), nor rate constants of emptying (CD: = 0.034/min, CO: = 0.033/min) were different between patients and controls. CONCLUSION: Abnormal gallbladder contractility does not seem to be a major cause of an increased risk of gallstone formation in Crohn's disease.

Adult↗