Biomedical subjects

H Waldner

Publications and source records attributed to H Waldner.

At least 55 records · Page 3Linked to original sources

PubMed1993

[Prevention of thrombosis in surgery of the extremities. Physical methods in thrombosis prevention].

Physical therapy procedures for the prophylaxis of thrombosis are part of basic medical therapy. Their effect has been documented by numerous individual observations, even though no prospective studies are available. Since the inconvenience to the patient is minor, they should be implemented in all surgical patients. In the case of patients at risk of thrombosis such as in orthopedic surgery, the effect of such procedures is not sufficient. In this case physical therapy procedures can only supplement the medical prophylaxis of thrombosis. The effectiveness of technically more complex physical procedures has been documented in small studies, but due to the high technical and personnel costs, the application is restricted.

Bandages↗

PubMed1993

[Venous thrombosis--clinical aspects and diagnosis].

Physical examination is in most cases not specific or sensitive enough to diagnose venous thrombosis. Only in rare cases is it possible to diagnose thrombosis by history and examination alone. However, when the case history indicates that risk factors are present, one must suspect thrombosis even if the clinical findings are uncharacteristic. In this situation the diagnosis must be verified by additional technical examinations.

Edema↗

PubMed1993

[Treatment of venous thrombosis].

In the treatment of deep vein thrombosis (DVT), a rapid clinical diagnosis supported by the appropriate equipment, the age of the patient, and the extent of the thrombosis are the major determinants of successful therapy. Active and conservative treatment should be aimed at the prevention of pulmonary embolisms, rethrombosis and elimination of the thrombus, while preserving venous valvular function, which in turn is essential to avoid the development of post-thrombotic syndrome. The treatment of acute DVT remains controversial. For this reason the indication, treatment, and recently published results of thrombectomy, thrombolysis, and the possibilities for preventing DVT are discussed.

Anticoagulants↗

PubMed1992

Antivirally protective cytotoxic T cell memory to lymphocytic choriomeningitis virus is governed by persisting antigen.

The basis of antiviral protection by memory cytotoxic T lymphocytes (CTL) was investigated in vivo and in vitro using lymphocytic choriomeningitis virus (LCMV) and recombinant vaccinia viruses expressing the LCMV-glycoprotein (vacc-GP) or -nucleoprotein (vacc-NP). The widely replicating LCMV with a tendency to persist induced solid long-term protective memory. The poorly replicating vaccinia recombinant viruses revealed in the vaccinated host that the antiviral capacity of the secondary immune T cell response and the protection against lethal LCM was dependent upon the immunizing antigen and its dose. Protection against lethal choriomeningitis is less sensitive to assess memory because it depends upon high levels of CTL precursors (p) and/or on an activated state of memory CTL. In contrast, antiviral protection measured as the capacity of the primed host to reduce virus titers after challenge infection correlated with elevated CTLp frequencies after immunization with live LCMV or recombinant vaccinia virus-expressing the major LCMV epitope. CTLp frequencies were constantly increased up to 70 d for LCMV immune mice, but rapidly decreased a few weeks after immunization with low dose vaccinia recombinant virus. For example, mice primed with 2 x 10(6) plaque-forming units (PFU) of vacc-NP, or 2 x 10(2) PFU, or 2 x 10(6) PFU of vacc-GP were antivirally protected on day 7 but not after day 30 when CTLp could not be measured any longer in vitro. However, greater priming doses of vacc-NP (10(4) or 2 x 10(6) PFU) as well as LCMV (2 x 10(2) PFU) induced elevated levels of CTLp and antiviral protection for 60 d or longer. Adoptive transfer experiments of immune spleen cells into syngeneic recipients without addition of antigen demonstrated that maintenance of the antiviral protective capacity of the transferred cells depended on the presence of viral antigen. Thus, antiviral protection by memory CTL may be rather short-lived since it is based on activated T cells continuously stimulated by persisting antigen. This is best achieved by high immunizing antigen doses yielded either by widely replicating viruses or high doses of poorly replicating recombinant vaccines.

Animals↗

PubMed1992

Hemodynamic effects following intraperitoneal infusion of pancreatic ascites fluid.

Severe necrotizing pancreatitis is accompanied by release of hemorrhagic ascites fluid (HAF), which is thought to be related to the occurrence and frequency of cardiocirculatory and pulmonary failure as a consequence of acute pancreatitis. The purpose of this study was to evaluate the role of HAF due to these systemic complications. Experiments were performed in 25 pigs (mean b.wt. 22 +/- 1 kg) under general anesthesia and mechanical ventilation. The animals received 50 ml/kg b.wt. i.p. of either physiologic saline solution (control CO, n = 9) or hemorrhagic ascites fluid (HAF, n = 16). HAF was obtained from 16 pigs with pancreatitis induced by intraductal infusion of bile salt. Eight animals in the HAF group were pretreated with indomethacin (10 mg/kg i.v. INDO/HAF). All animals were followed up for 6 h. Mean arterial pressure, cardiac output, and stroke volume fell significantly in the HAF (-25%, -27%, -27%) and in the INDO/HAF groups (-24%, -20%, -17%) as compared with controls (-6%, -6%, -6%). Also, left ventricular end-diastolic pressure (LVEDP) decreased by 52% and 48% in both HAF recipient groups, whereas LVEDP was unchanged in the control group. Myocardial contractility (Vmax) remained unaltered in all experimental groups. No significant differences in gas exchange and lung dry/wet weight ratio were observed. Lipase and PGI2 of the unpretreated HAF group rised to 203% and 198% in arterial blood at 6 h compared with unaltered levels in the control group. No increase of prostanoid concentrations was detected in the indomethacin-pretreated group, whereas lipase increase by a comparable extent as in the HAF group. We conclude that the early consequences of HAF are mainly characterized by systemic hypotension due to hypovolemia.

Acute Disease↗

PubMed1992

Vascular mechanisms to induce acute pancreatitis.

Vascular mechanisms are not standard tools to induce acute pancreatitis. They are used for special purposes to investigate the pathophysiologic significance of circulatory changes in acute pancreatitis. Because of the rich collateral network, occlusion of the main pancreatic arteries induces no pathological change. Complete occlusion of the venous outflow induces hemorrhagic necrosis of the pancreas, disturbances of the microcirculation, edema and focal parenchymal necrosis as in acute pancreatitis. In the last model, pancreatic and systemic alterations can be examined.

Acute Disease↗

PubMed1992

Blood flow and tissue oxygen pressures of liver and pancreas in rats: effects of volatile anesthetics and of hemorrhage.

The object of this investigation was to compare the effects of volatile anesthetics and of hemorrhage at comparable arterial blood pressures on splanchnic blood flow (radioactive microspheres) and tissue oxygenation of the liver and pancreas (surface PO2 [PSO2] electrodes). In contrast to earlier studies, we did not use identical minimum alveolar anesthetic concentration multiples as a reference to compare volatile anesthetics; rather, we used the splanchnic perfusion pressure. Under general anesthesia (intravenous chloralose) and controlled ventilation, 12 Sprague-Dawley rats underwent laparotomy to allow access to abdominal organs. Mean arterial pressure was decreased from 84 +/- 3 mm Hg (mean +/- SEM) at control to 50 mm Hg by 1.0 +/- 0.1 vol% halothane, 2.2 +/- 0.2 vol% enflurane, and 2.3 +/- 0.1 vol% isoflurane in a randomized sequence. For hemorrhagic hypotension, blood was withdrawn gradually until a mean arterial pressure of 50 mm Hg was attained. Volatile anesthetics and hemorrhage reduced cardiac output, and hepatic arterial, portal venous, and total hepatic blood flows by comparable degrees. Mean hepatic PSO2 decreased significantly from 30.7 +/- 2.6 mm Hg at control to 17.4 +/- 2 and 17.5 +/- 2 mm Hg during enflurane and isoflurane (each P less than 0.05) anesthesia, respectively. The decrease to 11.5 +/- 2.5 mm Hg was more pronounced during halothane anesthesia. Hemorrhagic hypotension was associated with the lowest hepatic PSO2 (3.4 +/- 1.3 mm Hg) and the highest number of hypoxic (0-5 mm Hg 86%) and anoxic PSO2 values (0 mm Hg 46%). Pancreatic blood flow and oxygenation remained unchanged from control during halothane and enflurane administration, whereas isoflurane increased both variables. Hemorrhagic hypotension slightly reduced pancreatic flow (-8%) but significantly decreased PSO2 from 58 +/- 5 mm Hg at control to 36 +/- 3 mm Hg, with 7% of all measured values in the hypoxic range. Thus, volatile anesthetics preserved pancreatic but not hepatic blood flow and tissue oxygenation in this rat model. Despite comparable effects on perfusion, the PSO2 of the liver and pancreas was the least during hemorrhagic hypotension compared to that with the anesthetics. Because the volative anesthetic-induced hypotension has such a different effect on splanchnic tissue oxygenation compared with hemorrhagic-induced hypotension, the authors conclude that the method of inducing hypotension may have different effects on oxygenation of various tissues.

Anesthetics↗

PubMed1991

Oleic acid induced pancreatitis in pigs.

An experimental model of edematous pancreatitis in pigs was established and measurement of pancreatic macro- and microcirculatory parameters and determinations of pancreatic enzymes (lipase, phospholipase A) and vasoactive mediators (prostanoids, kallikrein, kininogen) were performed. During general anesthesia the pancreas was isolated in situ. Pancreatic microcirculatory parameters were measured using videofluorescence microscopy after iv administration of FITC-Dextran. In hourly collected samples lipase and phospholipase A activities were determined enzymatically, concentrations of kallikrein, kininogen, and selected prostanoids were measured by radioimmunoassay. Two experimental groups were studied: (1) control (n = 9); (2) edematous pancreatitis induced by injection of oleic acid into the pancreatic artery (free fatty acid, ffa; n = 10). The animals were followed up for 6 hr. Systemic hemodynamic parameters remained constant in both groups. In the pancreatitis group pancreatic blood flow and O2-consumption decreased significantly (-55 and -49%), while pancreatic vascular resistance increased significantly (+50%). During baseline conditions 41% of all capillaries were perfused. In the pancreatitis group there were both areas with persistent stasis as well as areas with continuous perfusion. However, in the latter areas the portion of perfused capillaries decreased significantly to 27%. In the control group the portion of perfused capillaries remained constant. Liberation of lipase and phospholipase A especially into lymph and ascites fluid was measured during pancreatitis. Furthermore, considerable releases of kallikrein into lymph (+50%) and ascites (+800%) and a marked consumption of kininogen in lymph (+90%) and in ascites fluid (+80%) were measured. Activation of the arachidonic acid cascade and a significant release of prostacyclin and thromboxane A2 into pancreatic venous blood and lymph was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed1991

Micro-targeting: high efficiency gene transfer using a novel approach for the acceleration of micro-projectiles.

We have constructed a novel micro-projectile accelerating system for efficient gene transfer into cells in situ that avoids binding DNA to micro-projectiles and keeps the DNA in solution. Further, instead of a macro-projectile (or the equivalent), it accelerates the particles in a Bernoulli air stream. The micro-targeting approach directs highly dispersed particles to sites with diameters as little as 0.15 mm, allowing precise aiming to restricted tissues. The system is physically flexible and should therefore be adaptable to different tissues and species. Transient expression of the Escherichia coli beta-glucuronidase gene in immature wheat embryo scutella was obtained at a frequency of up to 3% of the treated cells in the surface layer. In tobacco SR1, we achieved many transgenic plants, and the efficiency of stable transformation with the neomycin phosphotransferase (NPTII) gene was approximately 10(-3) per exposed cell.

Cloning, Molecular↗

PubMed1991

[A new application of plastination in bone histology].

The plastination techniques originally developed for macroscopy can be modified for the preparation of plastinated sections for microscopy. Particularly good penetration of the specimen during preparation of the histological section is obtained, when the techniques described for freeze substitution, degreasing and forced impregnation with resin are employed. The different types of polymers are compared to determine the particular advantages and disadvantages of each. The sectioning technique and the use of histological stains are described for both undecalcified and decalcified bones. The modified Spalteholz technique with decalcification of sections and second plastination procedure for the preparation of transparent decalcified bone sections is described. This makes it possible to produce plane parallel standardized sections for morphometric examination of the vascular structure of the bone. The possible uses of the plastination for the histological examination procedures currently in use, such as fluorescence microscopy, microangiography and microradiography, are shown. The relative values of different microangiographic techniques have been determined for the first time by means of further developments of the Spalteholz and plastination techniques, because they have provided the possibility of standardizing sections. Thus, the plastination technique appears to be especially useful for the examination of microscopic specimens.

Animals↗

PubMed1991

[Surgery of the adrenal glands. Advantages and disadvantages of an anterior versus a posterior approach].

From Jan. 1984 until Oct. 1990 87 adrenalectomies in 75 patients were performed. In 29 patients the transabdominal anterior approach via a transverse upper abdominal laparotomy was carried out for unilateral left (18 pat.) or right adrenalectomy (11 pat.). 46 patients underwent 58 adrenalectomies using the posterior approach as described by Mayor. Using this approach with the patient in prone position, the 11th rib is resected, the pleural reflection identified, the Gerota's fascia incised and the suprarenal space exposed. When the anterior approach was used, blood transfusions were required in 34%. On the other hand, with the dorsal approach, a transfusion was necessary in only 4% of the patients. In 3 of 18 anterior left adrenalectomies a splenectomy was required (17%). The previous was not necessary in any patient having undergone a posterior adrenalectomy. Using the anterior approach postoperative hemorrhage occurred in 7%. No cases of bleeding were observed after posterior adrenalectomy. The average hospital stay was 14.6 days in the transabdominal and 8.5 days in the posterior group. The dorsal approach can only be used in cases in which the tumour is less than 5 cm. For larger of malignant tumours the transabdominal approach is mandatory. In conclusion the posterior adrenalectomy is superior to the anterior and should therefore be employed in appropriate cases.

Adrenal Gland Neoplasms↗

PubMed1990

Lesion patterns of vasoactive intestinal polypeptide-containing neurons in the myenteric plexus induced by clamping or transsection of rat jejunum.

The acute reactions of vasoactive intestinal polypeptide (VIP)-containing neurons in the myenteric plexus of the rat jejunum in response to circumferential clamping or transection/reanastomosis were evaluated in a detailed time course of up to ten days. Whereas in sham-operated controls VIP immunostaining was confined exclusively to varicose fibers, either clamping or transection induced the appearance of strongly VIP-immunoreactive beaded neuronal processes and neuronal perikarya in the oral part of the lesion one day postoperatively. After five days strongly immunostained varicose fibers orientated in the longitudinal axis of the gut towards the lesion reappeared suggestive of the onset of regenerative processes.

Animals↗

PubMed1990

[Pancreatic circulation in experimental biliary pancreatitis].

Measurements of pancreatic micro- and macrocirculation were performed to evaluate the pancreatitis-induced changes. Pigs were anesthetized and ventilated mechanically. Hypotension induced side-effects were avoided by adequate volume replacement. After laparatomy, splenectomy and gastroectomy the animals were enterotomized. Systemic hemodynamic parameters were monitored as well as pancreatic blood flow (Q), which was measured electromagnetically, and arterial and portal-venous blood gases. Pancreatic microcirculatory parameters were observed using fluorescence-videomicroscopy after i.v. administration of FITC dextran 150 and FITC labeled autologous erythrocytes. The pigs were randomly assigned to a control (n = 9) and a pancreatitis group (n = 10), the later being induced by the retrograde infusion of sodium-taurocholate. Systemic and pancreatic macrohemodynamic parameters remained constant in both groups, except for avdO2 and O2-consumption (O2-c) decreasing significantly in the pancreatitis group. At baseline 42% of all capillaries were perfused in both groups. In pancreatitis we detected focal areas with persistent stasis and areas which were continuously perfused. In these areas the portion of capillaries perfused by erythrocytes increased significantly to 67%. This was accompanied by an extravasation of FITC dextran. The finding of an unchanged Q beside reduced O2-c and avdO2 during pancreatitis is explained by the changes in pancreatic microcirculation. Focal stasis was observed beside areas showing typical signs of an acute inflammation: increased macromolecular permeability and capillary recruitment, e.g. oedema and hyperaemia.

Acute Disease↗

PubMed1990

[A combination surgical-radiological approach for the treatment of carcinoma of the hepatic duct bifurcation with involvement of both hepatic duct trunks].

The only curative treatment to proximal bile duct cancers with involvement of both hepatic ducts is liver transplantation. A curative resection with wide lateral clearance is limited due to the neighbourhood of vital anatomic structures in the liver hilum. The majority of patients with bile duct cancers is over 60 years of age and due to concomitant disease, they do not fulfill the requirements for liver transplantation. Our treatment strategy in adequate cases is palliative tumor resection and reconstruction of bile passage by sutureless biliodigestive anastomosis as proposed by Rodney Smith. We treated 11 patients with this method, in 5 patients an additive combined radiotherapy by percutaneous radiation and intraluminal after-loading therapy was performed. Our results indicate that this strategy leads to effective palliation in cases provided that only microscopic residual tumor is left in situ (R1-resection). Our observed survival times compare favorably to survival times after liver transplantation (average survival time 11.5 months median survival time 10 months).

Aged↗

PubMed1990

[Therapeutic concept in incidentaloma of the adrenal gland].

The operative approach to adrenal incidentalomas depends on the subclinical hormoneactivity and the risk of malignancy. In our 18 patients there were two pheochromocytomas (3 and 5 diameter), one with subclinical hormoneactivity and three malignancies, an adrenocortical carcinoma, a metastasis without primary and a lymphoma. The malignant tumors were larger than 5 cm. As tumors smaller than 3 cm are usually benign they should be observed. Because of the risk of malignancy there is a relative indication to operate on larger tumors.

Adrenal Gland Neoplasms↗

PubMed1989

Release of arachidonic acid metabolites during acute pancreatitis in pigs.

The pancreatic release of arachidonic acid metabolites was studied in a porcine model of acute pancreatitis. In situ isolation of the pancreatic gland enabled selective collection of pancreatic venous blood, pancreatic lymph, and ascites fluid. Three experimental groups were studied: 1) control (n = 9); 2) hemorrhagic pancreatitis induced by injection of 5% bile salt (sodium taurocholate) into the pancreatic duct (n = 10); and 3) edematous pancreatitis induced by injection of free fatty acid (FFA) into the pancreatic artery (n = 10). Determinations of cyclooxygenase metabolites were performed by radioimmunoassay; lipoxygenase metabolites (LTC4, LTD4) were measured by radioimmunoassay after purification by high-performance liquid chromatography. Prostaglandin (PG)F1 alpha, thromboxane B2, and PGF2 alpha concentrations were almost doubled in the lymph of the FFA group during pancreatitis, as were PGF1 alpha levels in pancreatic venous blood. However, concentrations of cyclooxygenase metabolites remained unchanged in the control group and in the bile salt group. Concentrations of LTC4 and LTD4 in lymph and ascites fluid of both pancreatitis groups increased from about 50 pg/ml to a mean level of 600 pg/ml at 6 h. Leukotriene concentrations in the control group were consistently below 50 pg/ml. The results of this study indicate that above all LTC4 and LTD4 are released from the organ and that these arachidonic acid metabolites may be also involved in the events following acute pancreatitis contributing to the systemic effects of the disease.

Acute Disease↗

PubMed1989

Thoracic manifestations of internal pancreatic fistulas: report of five cases.

Thoracic manifestations of internal pancreatic fistulas are rare. During the last 8 yr, we have treated one patient with a mediastinal pseudocyst, three patients with pancreaticopleural fistulas, and one patient with a pancreaticobronchial fistula. Recurrent pleural effusions represent one of the main clinical features in this entity, and can often lead to false diagnoses. Determination of pancreatic enzyme activity, as well as the combination of ultrasonography, computerized tomography, and endoscopic retrograde cholangiopancreatography (ERCP), enable the establishment of the diagnosis. A complete pancreatic evaluation is the rationale for an adequate and efficient therapy which should always aim at a focal assentation.

Adult↗

PubMed1988

[Early phase of healing of anastomoses with special reference to peritonitis and ischemia].

Experimental sutureless colonic anastomosis was evaluated under various conditions during the first 24 postoperative hours. Adaptation of large bowel segments was achieved by interrupted inverting sutures, which were removed after one hour. This short adaptation period was sufficient for fibrinous contact of bowel segments. Breaking strength of intestinal anastomosis was determined under normal conditions, in peritonitis, complete ischemia and unilateral ischemia of one bowel segment. As control parameter breaking strength of conventional anastomosis was determined under normal conditions. We obtained the following results: 1) Sutureless anastomosis exhibited significantly lower breaking strength than conventional anastomosis. 2) Sutureless anastomosis showed a significant increase in breaking strength under normal conditions after the first 6 h, on the contrary breaking strength remained at lower levels in peritonitis. 3) In complete ischemia anastomotic failure was observed even after 3 h of adaptation. Therefore breaking strength was not measurable. 4) Under unilateral ischemia breaking strength of intestinal anastomosis was significantly lower than under normal conditions.

Anastomosis, Surgical↗