Biomedical subjects

R Hoffmann

Publications and source records attributed to R Hoffmann.

At least 307 records · Page 17Linked to original sources

PubMed1993

Retransplantation of the liver--a seven-year experience.

Three hundred and four patients underwent 362 liver transplants between July 1984 and April 1992. Fifty-eight retransplants were performed in 44 patients (14.5%). Thirty-four patients underwent two (77.3%), seven patients three (15.9%), two patients four (4.5%), and one patient five (2.3%) transplants. Poor function accounted for 23 retransplants (6.4%), technical problems for 19 retransplants (5.2%), and rejection for 15 retransplants (4.1%). One-month patient survivals after retransplantation for poor function, technical problems, or rejection were similar (79.0%, 73.4%, and 80.0%, respectively). No difference in retransplantation rates were seen between adults and children receiving whole liver transplants (WLT) (11.6% versus 19.1%). However, retransplantation for poor function was more common in pediatric recipients receiving reduced-size liver transplants (RLT) (20.0% versus 0.0%, P < 0.01), while retransplantation for hepatic artery thrombosis (HAT) was more common in pediatric recipients receiving WLT (16.7% versus 2.8%, P < 0.05). The presence of multiorgan system failure of greater than four was associated with a high mortality (90%), whereas patients undergoing emergent retransplantation who had less than four systems fail had a survival of 73.9% and patients who underwent elective retransplantation had a survival rate of 81.8%. Length of stay and cost of liver transplantation was higher in patients undergoing retransplantation when compared with primary transplants (29.7 +/- 14.9 days versus 58.4 +/- 38.9 days and $122,358 +/- 59,782 versus $289,302 +/- 126,907, P < 0.01). The overall actuarial one-year patient survival in primary transplants was 86.6% and in retransplants 74.8%, and at five years these were 71.4% versus 62.5%, respectively (P < 0.05). Our results support continued retransplantation of the liver unless the patient's medical condition dictates otherwise.

Adolescent↗

PubMed1993

Effect of aging and bolus variables on pharyngeal and upper esophageal sphincter motor function.

Effect of aging, bolus volume, temperature, and consistency on the pharyngeal peristalsis, as well as the effect of aging on the upper esophageal sphincter (UES) resting pressure and its response to esophageal distension by air and balloon, were studied in 14 young and 12 healthy elderly volunteers. In both age groups there was no significant volume or temperature effect on amplitude, duration, or velocity of the pharyngeal peristalsis. Compared with water swallows, mashed potato swallows resulted in a significant increase in the amplitude and duration of the hypopharyngeal peristaltic pressure wave (P < 0.05). For water swallows, the amplitude and duration of the peristaltic pressure wave in the hypopharynx were significantly increased in the elderly compared with the young group (P < 0.01). UES resting pressure in the elderly measured 43 +/- 5 (SE) mmHg and was significantly less than that of the young (71 +/- 8 mmHg; P < 0.01). Magnitude of the UES pressure decrease because of esophageal distension by air, as well as magnitude of its pressure increase because of esophageal balloon distension, was similar among young and elderly. 1) Contrary to common expectations, the parameters of the pharyngeal peristaltic pressure wave do not deteriorate in the elderly in their seventh and eighth decade. 2) Compared with the young, hypopharyngeal pressure wave amplitude and duration are significantly increased in the elderly. This increase could be caused by an adaptation response to a pharyngeal outflow compromise. 3) Pharyngeal peristaltic pressure wave amplitude and duration, but not its velocity, are modulated by the bolus consistency. This modulatory mechanism is preserved in the elderly. 4) Although UES resting pressure is significantly decreased in the elderly, its pressure response to esophageal distension by air and balloon is preserved.

Adult↗

PubMed1993

Purification and quantitative analysis of nucleic acids by anion-exchange high-performance liquid chromatography.

A novel and reliable high-performance liquid chromatography (HPLC) method is described for the purification and quantification of double-stranded DNA. The nucleic acids may be obtained by polymerase chain reaction (PCR) or as restriction fragments from enzymatic cleavage; the separated products are devoid of contaminating material like agarose, ethidium bromide or non-specific DNA sequences. Because of the non-destructive nature of this HPLC procedure, the purified DNA is optimally suited for cloning experiments. The DNA separation by HPLC has major advantages when combined with reverse transcription (RT)-PCR. This is exemplified by analysis of the TNF-alpha mRNA obtained from endotoxin-elicited rat liver macrophages. If the standard procedure of Northern blotting is compared with the combination of RT-PCR and quantification of the PCR products by HPLC, it is obvious that the dynamic changes of tumor necrosis factor (TNF)-alpha mRNA synthesis are at least as precisely reflected with the RT-PCR/HPLC combination. The latter method is presented as a reliable and powerful tool for quantitative studies on gene expression.

Actins↗

PubMed1993

Control of motion of tibial fractures with use of a functional brace or an external fixator. A study of cadavera with use of a magnetic motion sensor.

A computer-linked magnetic motion transducer was used to monitor and record the six components of motion of the bone fragments in eight cadaveric tibiae in which a simulated, oblique fracture of the middle of the shaft had been stabilized with a functional brace. The limbs were mounted in a servo-hydraulic testing frame, and a cyclic load of 150 newtons was applied along the axis of the tibia. Motion sensors, attached to each side of the fracture, measured and displayed the values of the three translations (axial, anterior-posterior, and medial-lateral), the axial rotation, and the two angulations (anterior-posterior and varus-valgus) as they occurred. Although only an axial load was applied, the off-axis motions were comparable in magnitude with the motion along the axis. The elastic (recoverable) translations of the fragments ranged from 0.5 to 1.9 millimeters, about four to ten times larger than the corresponding motions that were recorded in an earlier study of such fractures that had been stabilized with two types of external fixators. The recoverable rotation and angulations of the fragments of the limbs in the functional brace ranged from 0.7 to 1.2 degrees, about ten times those recorded when the external fixators were used.

Braces↗

PubMed1993

[Diagnostic possibilities of sonography: ankle joint, foot and Achilles tendon].

In patients with soft tissue swelling and pain of the foot and ankle, ultrasonography is a simple and reliable diagnostic procedure to demonstrate joint effusions or a tendovaginitis which may have caused the symptoms of the patient. The diagnostic puncture of a joint is only necessary to determine the kind of effusion. The diagnostic workup of patients with acute and chronic instability of the proximal ankle joint benefits from the sonographic measurement of the talus tilt and of the anterior drawer. As the diagnostic performance is equal to the radiologic stress test, X-ray exposure can be avoided. As the anatomic structure of the achilles tendon causes the typical fibrillary sonographic pattern, structural changes due to tendinitis or tendon rupture can easily be diagnosed.

Achilles Tendon↗

PubMed1993

[Standardized ultrasound diagnosis of instability after dislocation of the upper ankle joint].

The anterior drawer was evaluated sonographically under standard conditions (150 N load, 7.5 MHz linear scanner) in 95 patients with severe ankle sprain. A simple geometric construct of subsidiary lines set up with the help of a goniometer on the videoprints (enlargement 1.5 X) enabled a standardized interpretation of the anterior drawer (pathologic > or = 3 mm). Thus, the definition of poorly reproducible reference points for sonographic measurements became avoidable. In 60 patients a rupture of the lateral ankle ligaments was diagnosed, in 35 patients the findings were recorded as severe ankle sprains without ligament rupture. Compared with the radiological anterior drawer and talar tilt, the dynamic sonographic measurement of the anterior drawer showed the better values from the aspects of sensitivity, specificity and accuracy (> or = 0.93). In our own practice sonographic measurement of anterior drawer has replaced stress radiograms in diagnosis of ankle joint instabilities after severe ankle sprains.

Adolescent↗

PubMed1993

[Prevention of thromboembolism in hip fracture: unfractionated heparin versus low molecular weight heparin ( a prospective, randomized study)].

In a prospective, randomized study in patients with hip fracture we discuss whether a single dose of low-molecular-heparin (Sandoparin) has the same effect as a tripple dose of standard-heparin (Liquemin: 3 x 5000 I.E.) The first dose of low-molecular-heparin respectively standard-heparin is given in the emergency room before the operation. Between 4th and 6th day following operation the patients were screened for deep vein thrombosis: Clinical examination, Liquid Crystal Contact Thermography (LCCT), colour coded ultrasound examination and with phlebography. 33 patients have been treated with standard-heparin and 35 with low-molecular-heparin. In the group of standard-heparin 30% of all the patients showed a deep vein thrombosis, whereas only 17% deep vein thrombosis were found in the group treated with low-molecular-heparin. But to reach statistical significance in both groups 60 patients are needed. Postoperative haemorrhagic complications were seen in 6.1% in the group of standard-heparin and in 8% in the group of low-molecular-heparin. The LCCT and the ultrasound examination were compared with the phlebography. The LCCT had a sensitivity of 92% and a specificity of 85%. The ultrasound examination had a sensitivity of only 15%! Therefore the ultrasound examination is an unsuitable screening method to detect deep vein thrombosis in patients with fractures of the proximal end of the femur.

Aged↗

PubMed1993

[New diagnostic methods--ultrasound and clinico-chemical procedures in diagnosis of ischemia].

Stress-echocardiography represents a new non-invasive, alternative approach in the assessment of patients with coronary artery disease. By means of dynamic or pharmacological stress or by atrial pacing regional wall motion abnormalities can be induced, which can be identified by 2D-echocardiography. Beyond the indirect detection of ischemia this approach allows a better quantification of the amount of ischemia and of global LV function, which is advantageous compared to stress ECG recording or myocardial scintigraphy. Disadvantageous is however, the subjective reading of the echo itself. In experienced hands stress-echocardiography has proven to be as sensitive and specific as myocardial scintigraphy. Recently, in addition the diagnostic potential of myocardial cell injury has been improved by the detection of specific antibodies versus Troponin T. In comparison with conventional biochemical markers of myocardial cell necrosis Troponin T analysis has been proven to be superior in postoperative or traumatic cardiac damage or in the setting of acute myocardial infarction. In this situation the time window is improved by an earlier rise compared to CK and a longer detection rate compared to lactate dehydrogenase.

Adenosine↗

PubMed1993

[Laparoscopic laser cholecystectomy].

Although studies on laparoscopic cholecystectomy using laser surgery show no significant difference when compared to those done with cautery, the use of a laser does have substantial assets. A highly accurate dissection as well as coagulation of arteries up to a size 3 mm can be achieved if the appropriate type of laser is chosen. Our cases have shown us that trauma to the tissue due to laser surgery is minimal and causes less damage than when a monopolar hook electrode is used. The fact that patients with laser surgery have less pain than those where the operation was performed using the monopolar electrode has been noticed by various authors. The minor heat production and the better healing tendency after laser surgery may be an explanation of this phenomenon.

Acute Disease↗

PubMed1993

[Therapy of bile duct calculi from the surgical viewpoint].

Stones in the ductus choledochus can be managed endoscopic-retrograde, percutaneously-transhepatic (in case it is impossible to reach the papilla vateri) or surgically. If choledocholithiasis is found on performing a laparoscopic cholecystectomy management nowadays consists of splitting the therapeutic regimen: Laparoscopic cholecystectomy and postoperative ERCP and papillotomy. A one time surgical procedure is certainly going to be more frequent in the future: laparoscopic cholecystectomy and revision of the choledochus. This procedure has great advantages for the patient as it needs just a single operation and is easy on his papilla. The necessary laparoscopic instruments have to be perfected and the procedure demands a substantial amount of time plus a high surgical standard.

Cholangiopancreatography, Endoscopic Retrograde↗

PubMed1993

[How often does an aneurysm of the popliteal artery rupture?].

Rupture of a popliteal artery aneurysm is an unusual complication and did occur six times in our series of 252 popliteal artery aneurysms that underwent operative repair from January 1965 to December 1991. Rupture while equally serious as thrombosis of the popliteal artery aneurysm of distal embolization from the aneurysm, is reported as an exceedingly unusual complication. Reported incidence of rupture is less than 2 to 4 percent in most large series and was 2.4 percent in the present series.

Aged↗

PubMed1993

Regulation of tissue inhibitor of metalloproteinases-1 gene expression by cytokines and dexamethasone in rat hepatocyte primary cultures.

The steady-state levels of extracellular matrix proteins are regulated by the rates of their synthesis and degradation. Metalloproteinases and their specific inhibitors, tissue inhibitor of metalloproteinases-1 and -2 are believed to play a crucial role in extracellular matrix protein degradation. Here we show that the tissue inhibitor of metalloproteinases-1 is expressed in rat hepatocytes in primary culture and regulated by inflammatory cytokines. Rat hepatocytes constitutively express mRNA of tissue inhibitors of metalloproteinases-1 at a low level. Incubation with conditioned medium from lipopolysaccharide-stimulated human monocytes led to a dramatic induction of mRNA of tissue inhibitors of metalloproteinases-1. The inflammatory cytokines interleukin-1 beta, interleukin-6, interleukin-11, leukemia inhibitory factor and ciliary neurotrophic factor were also capable of stimulating expression of mRNA of tissue inhibitors of metalloproteinases-1. Among these cytokines interleukin-6 was the most potent stimulator. The combination of interleukin-1 beta, interleukin-6 and interleukin-11 synergistically up-regulated mRNA of tissue inhibitors of metalloproteinases-1. The synthetic glucocorticoid dexamethasone dose dependently inhibited constitutive and interleukin-6-induced expression of tissue inhibitors of metalloproteinases-1. A possible involvement of tissue inhibitor of metalloproteinases-1 in the pathogenesis of liver fibrosis and cirrhosis is discussed.

Animals↗

PubMed1993

[New procedures in transesophageal echocardiography: multiplane transesophageal echocardiography and transesophageal stress echocardiography].

Multiplane transesophageal echocardiography is a new development in transducer technology, which allows by rotation of the transducer to obtain not only transverse and longitudinal planes but also all intermediate planes. Exterior control allows continuous rotation of the scanning plane from the conventional transverse plane, corresponding to 0 degree, to the longitudinal plane, corresponding to 90 degrees and further to a left-right inverted transverse plane, corresponding to 180 degrees. Although the echoscope tip, which houses the rotatable transducer, is slightly larger than conventional probes, in our clinical experience of well over 400 cases, intubation of the esophagus is not more difficult than with the mono- or biplane probe. In comparison with the biplane technique the adjustment of intermediate planes is easier and less unpleasant for the patient, since mechanical irritation due to sideward flexion of the probe is less often necessary. Plane rotation, effected by control buttons in the echoscope handle, takes eight seconds from 0 degree to 180 degrees. The probe incorporates a 5 MHz phased array transducer, which alternatively works at 3.7 MHz. Pulsed, continuous and color Doppler are also integrated. Multiplane transesophageal echocardiography was used to investigate several clinical questions. In 41 patients with aortic valve stenosis the valve area was determined by planimetry. The valve area was measured in an individually aligned short axis view (between 50 degrees and 70 degrees). A high correlation (r = 0.95; Y = 0.9 X + 0.1; p < 0.01) with invasively determined valve areas by the Gorlin formula was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1993

[Digital magnification mammography. A new technique for improved visualization of microcalcifications in breast cancer diagnosis].

Special X-ray tubes with electromagnetic focusing provide a spatial resolution of up to 50 lp/mm at a focal spot size of about 10 microns. Radiographs of whole female breast specimens as well as paraffin blocks were taken at magnifications up to x 10. The initial results revealed numerous microcalcifications smaller than < 100 microns that had not been detected by conventional grid mammography. The combination of a microfocal spot with digital radiography results in as yet unmatched resolution of microcalcifications and makes the advantages of image post-processing available to mammography. However, specific types of calcification could not be established in malignant or benign histological findings.

Breast Diseases↗

PubMed1992

[Percutaneous endoscopic gastrostomy (PEG) for long-term nutrition--comparison of 2 different caliber tubes].

Percutaneous endoscopic gastrostomy (PEG) is often used nowadays for long-term enteral nutrition in patients with swallowing disorders and severely altered esophageal-duodenal transit. The most common indications for gastrostomy tubes were neurological disturbances and malignancies of the oropharynx and esophagus. We compared in a prospective sequential trial PEG-tubes of two different sizes (2.9 mm [CH-9] vs. 4.8 mm [CH-15]) with respect to placement, complications, durability and handling. The tube was successfully placed in 51 of 52 patients (98%). In 1 patient placement was impossible due to missing diaphanoscopy. The mean observation period was 22 weeks for the CH-9-tubes (n = 28) and 14 weeks for the CH-15-tubes (n = 23). The only early complication was 1 case with a hemorrhage at the site of implantation (CH-15). In both groups 2 cases of local infection were noted. In the CH-9-group 2 PEG-tubes disappeared into the stomach and in 1 case a cicatricial granuloma developed. In the CH-15-group a leak occurred 10 days after implantation. All complications were treated conservatively. There was no causal relationship between the size of tube and the complications. The period of implantation was mostly limited by the death due to the underlying disease of the patient and was not related to the type of PEG-tube. We conclude the both PEG-tubes were easy to place, safe and effective means of providing enteral nutrition. We would, however, recommend CH-15-tubes for long-term nutrition, since in our experience they were less frequently obstructed and handling for the nurses was easier.

Adult↗

PubMed1992

[Helicobacter pylori colonization of the gastric remnant following partial resection].

Colonization by Helicobacter pylori (HP) in 53 patients after remote gastric surgery and Roux-en-Y anastomosis was investigated using a rapid urease test (CU-Test) and histology (H&E and Giemsa stain). The pH-value of gastric juice was measured. HP infection of the gastric remnant was found in 56% of 43 patients after partial resection and in no case after total gastric resection. HP-positive and HP-negative patients were comparable in age, sex distribution, indication and technique of gastric operation (except for total gastrectomy with jejunal gastric replacement), intake of acid inhibiting drugs and antibiotics was well as in the presence or absence of a macroscopically visible pathology of the gastric mucosa. On the other hand, the two groups differed in their histological findings, pH-value of gastric juice and time interval since surgery. HP infection of gastric remnants is associated with significant glandular atrophy and an additional rise in gastric intraluminal pH compared with HP-negative patients. Both changes may involve an increased risk for gastric cancer. In this report on patients with Y-en-Roux operation there is no decrease in gastric HP-colonization with an increasing interval since the time of operation, but rather an increase. This phenomenon seems to depend on the absence of enterogastric reflux.

Anastomosis, Roux-en-Y↗

PubMed1992

[Internistic therapy possibilities in therapy-resistant Crohn disease].

About 20% of patients with active Crohn's disease do not respond to acute-phase-therapy with glucocorticoids at an initial dose of 60 mg prednisolone-equivalent and stepwise dose reduction every week. In case of primary failure of this therapeutic scheme the dose of glucocorticoids has to be enhanced. If necessary a combination with total parenteral nutrition or tube feeding should be used. In case of early recurrence of inflammation during dose reduction or chronic steroid-dependent disease activity a combination of glucocorticoids with Azathioprine will be successful in about 75% of patients. In addition a combination of glucocorticoids with tube feeding (elemental or polymeric diet) will lead to remission of inflammatory activity in about 60 to 70% of these patients. In patients, who are still refractory to these therapeutic procedures, operation should be discussed.

Anti-Bacterial Agents↗

PubMed1992

Structure and molecular modeling of GABAA receptor antagonists.

The recently described potent and selective GABAA antagonist SR 95531 (gabazine) is compared to six other GABAA antagonists: (+)-bicuculline, (-)-securinine, (+)-tubocurarine, iso-THAZ, R-5135, and pitrazepine. Starting from ab initio molecular orbital calculations performed on crystal atomic coordinates, attempts were made to identify in each structure the functional groups that are involved in receptor recognition and binding. A molecular modeling study revealed that (a) all compounds possess accessible cationic and anionic sites separated by an 4.6-5.2 A intercharge distance, (b) the antagonistic nature of the compounds can be explained by the presence of additional binding sites, (c) the correct spatial orientation of the additional binding sites is crucial for GABAA selectivity, and (d) the criteria determining the potency of the antagonist effect are an accurate intercharge distance (greater than 5 A) and the existence of hydrogen-bonding functionalities on one of the additional ring system. The presented pharmacophore accounts also for the inactivity of closely related compounds such as (-)-bicuculline, adlumidine, virosecurinine, allosecurinine, and the 4,6-diphenyl analogue of gabazine.

Alkaloids↗