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Biomedical subjects

R Langer

Publications and source records attributed to R Langer.

At least 379 records · Page 21Linked to original sources
PubMed1991

[Superselective intra-arterial DSA in femur head necrosis and femoral neck fractures].

The prospective study includes 25 patients without pathology of the femoral head for the evaluation of the normal femoral head perfusion. In addition 34 patients with femoral head necrosis underwent i.a. DSA preoperatively before pedicled pelvic bone grafting. 15 patients after pelvic bone graft operation and 7 patients with medial femoral head fracture were also examined via superselective DSA. In cases with femoral head necrosis a rarefaction or interruption of the rami nutricii proximales, or an occlusion of the medial circumflex femoral artery were observed. Patients with medial femoral neck fracture showed an interruption of the rami nutricii proximales of the femoral head. Postoperative DSA--after pedicled pelvic bone graft--revealed a regular arterial graft perfusion in 82%.

Adult↗
PubMed1991

[Transcranial Doppler sonography in cerebrovascular diseases].

A review of our 1 1/2 years' experience with transcranial Doppler sonography (TCD) is given. In total, 619 TCD examinations were performed. Considering physiological variations of blood flow velocities in the intracranial arteries, TCD findings in stenoses and occlusions of the extracranial and intracranial brain-supplying arteries as well as in intracranial vasospasms were evaluated. In patients with leptomeningeal anastomoses demonstrated by TCD in the region of the peripheral middle cerebral artery, the regional cerebral blood flow was measured by 99mTc-HMPAO-SPECT. The value and limitations of TCD in cerebrovascular diseases and the indications to TCD examination of the intracranial arteries are discussed.

Carotid Artery Diseases↗
PubMed1991

[The place of angiography and radiologic intervention before and after liver transplantation].

The study demonstrates the value of angiography and radiological interventions before and after liver transplantation. From September 1988 till February 1991 84% out of 124 hepatic transplant recipients underwent pretransplant angiography evaluation for the exact demonstration of arterial and portal venous blood supply of the liver. Posttransplant angiography was performed in cases with suspected vascular complications, chronic rejection, and spleno-hepatic steal syndrome. Radiological interventions were performed for bacteriological examination and percutaneous drainage of encapsulated fluid collections.

Angiography↗
PubMed1991

Synthetic polymers seeded with chondrocytes provide a template for new cartilage formation.

A new approach for tissue creation using synthetic biocompatible and biodegradable polymers as templates onto which cells are seeded is presented. This report concerns the generation of homogeneous plates of stable mature cartilage in vivo. The delivery of chondrocytes on synthetic polymers configured to provide a large surface area for cell attachment and thus to allow cell function and survival by diffusion of nutrients has resulted in the creation of macroscopic plates of up to 100 mg of new cartilage subcutaneously in 19 of 21 animals. The approximate dimensions and configuration of the original templates were maintained as new cartilage was formed and the polymers resorbed.

Animals↗
PubMed1991

Tissue engineering by cell transplantation using degradable polymer substrates.

This paper reviews our research in developing novel matrices for cell transplantation using bioresorbable polymers. We focus on applications to liver and cartilage as paradigms for regeneration of metabolic and structural tissue, but review the approach in the context of cell transplantation as a whole. Important engineering issues in the design of successful devices are the surface chemistry and surface microstructure, which influence the ability of the cells to attach, grow, and function normally; the porosity and macroscopic dimensions, which affect the transport of nutrients to the implanted cells; the shape, which may be necessary for proper function in tissues like cartilage; and the choice of implantation site, which may be dictated by the total mass of the implant and which may influence the dimensions of the device by the available vascularity. Studies show that both liver and cartilage cells can be transplanted in small animals using this approach.

Animals↗
PubMed1991

Transcranial Doppler sonography: collateral pathways in internal carotid artery obstructions.

Fifty-four patients with stenoses and occlusions of the extracranial internal carotid artery (ICA) demonstrated by intravenous digital subtraction angiography (IVDSA) were studied by extracranial duplex and transcranial Doppler. Two hundred healthy volunteers served as control group. Intracranial collateralization was demonstrated in 32 patients with ICA stenoses greater than 80% and occlusions. Twelve patients with unilateral and 8 patients with bilateral ICA obstructions greater than 80% showed collateral supply via the anterior (ACA) and/or posterior cerebral artery (PCA). In 5 cases of unilateral ICA occlusion and in 7 patients with bilateral ICA stenoses greater than 80% and occlusions, the ophthalmic artery and ACA and/or PCA served as collateral vessels. Five patients with ICA occlusions showed leptomeningeal anastomoses in the region of the postocclusive middle cerebral artery (MCA). All 54 patients showed normal time-mean flow velocity in the post-obstructive MCA. In unilateral ICA stenoses greater than 80% and occlusions, the pulsatility index in the ipsilateral MCA was reduced in comparison with the contralateral side, indicating that this parameter is more sensitive to hemodynamic effects of ICA obstructions than time-mean velocity.

Angiography, Digital Subtraction↗
PubMed1991

[Intra-arterial chemoembolization of non-resectable hepatocellular carcinoma].

During a period of nine months, fifteen patients with extensive hepato-cellular carcinomas were subjected to palliative arterial chemo-embolisation using doxorubicin and cisplatin in an emulsion with Lipiodol and/or Spherex particles. Two patients (stage Child C) died within two weeks as the result of liver failure. The remaining thirteen patients showed improvement in their general condition. Subsequent CT showed evidence of tumour reduction and reduction of ascites. Gas production in the tumour was considered as evidence of tumour necrosis. Biochemical results confirmed these findings with a fall of AFP as tumour marker indicating tumour regression.

Aged↗
PubMed1991

Vascular graft infection: detection by 123I-labeled antigranulocyte antibody (anti-NCA95) scintigraphy.

A total of 40 scintigraphic examinations were performed after vascular reconstructive surgery in 27 patients in whom there was a clinical suspicion of vascular graft infection. Whole-body gamma camera images were obtained at 4 and 24 h after i.v. administration of 111 MBq 123I-labeled antigranulocyte antibody Anti-NCA95. Scan results were interpreted without clinical information and were subsequently correlated with computed tomography. Prosthetic vascular graft infection was confirmed in 9 patients and excluded in 18 by surgical findings, bacteriology and/or clinical course. Scintigraphy revealed true-positive results in 16 of 40 and false-negative results in 1 of 40 examinations. True-negative results were found in 19 and 16, false-positive results in 4 and 7 examinations at 4 and 24 h p.i., resp. The sensitivity was calculated to be 94% for both early (4 h) and late (24 h) images whereas the specificity was 83% and 70%, resp. In all cases the application of the murine antibody was safe and no side effects or complications were noted. Limitations of this diagnostic procedure are accumulations of granulocytes in hematomas which may be observed in the non-complicated early course following reconstructive surgery.

Aged↗
PubMed1991

Verapamil and the synthesis of prostacyclin in human veins.

The synthesis of the vasodilator prostacyclin (PGI2) depends on the intracellular calcium concentration. For this reason the purpose of this study was to document the effects of verapamil (1), a slow calcium channel blocking agent on venous tissue. Human varicose veins were studied which were removed by a stripping operation. The veins were investigated ex vivo and in vitro. For ex vivo studies 11 patients were given 0.01 g 1 i.v. during the operation. In vitro experiments were carried out by an addition of 22 mumol/l 1 to the incubate. The synthesis of PGI2 was studied according to the inhibition of the ADP induced platelet aggregation without and with addition of substrate (prostaglandin endoperoxide H2). 1 did not induce changes in the synthesis of PGI2, neither after administration to patients nor after addition to the incubation fluid compared to control vessels without addition of 1.

Adenosine Diphosphate↗
PubMed1991

Iatrogenic injuries to the ureter during gynecologic and obstetric operations.

Iatrogenic injuries to the ureter are hazardous complications of pelvic and vaginal operations, causing severe morbidity and even mortality. Eighteen such instances that occurred during the last 30 years are analyzed. Most of the injuries were associated with attempts to achieve hemostasis without proper identification of the ureter. The incidence of ureteral injuries declined during the years concomitantly with the improvement of surgical techniques. The proper identification and, when necessary, isolation of the ureter during operations in which there is a risk is crucial in reducing the incidence of ureteral injuries. Those diagnosed at the time of injury and treated with end to end anastomosis had the best results. Delayed diagnosis and treatment were associated with poor end results. The English literature is reviewed.

Adnexa Uteri↗
PubMed1991

Outcome of continued pregnancies after first- and second-trimester cervical dilatation by laminaria tents.

In 21 pregnant women (seven in the first trimester and 14 in the second trimester), laminaria tents inserted for induction of elective abortion were removed after dilatation had been achieved, but upon the patient's request, the abortion was not carried out. Four patients again changed their minds and had uncomplicated induced abortion after reinsertion of the laminaria tents. Seventeen patients continued their pregnancies: Fourteen had term deliveries, two had premature deliveries, and one had a spontaneous abortion at 10 weeks' gestation, 2 weeks after laminaria removal. None of the patients suffered infectious morbidity, including three untreated patients with positive cervical cultures for chlamydia, who experienced normal pregnancies and deliveries.

Abortion, Induced↗