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Biomedical subjects

R Langer

Publications and source records attributed to R Langer.

At least 595 records · Page 33Linked to original sources
PubMed1980

A simple method for studying chemotaxis using sustained release of attractants from inert polymers.

Chemotaxis of the bacterium Escherichia coli and the planarian Dugesia dorotocephala toward a variety of substances impregnated in sustained-release polymers has been demonstrated. Tests were carried out in soft agar and in aqueous medium with highly consistent results. The simplicity of this method may make it particularly useful for rapid qualitative screening of new wild-type and mutant strains of bacteria for chemotaxis toward nonmetabolites. The cost, ease of fabrication, and the facility with which they can be utilized in test systems suggest that these sustained-release vehicles will provide a new and general method of creating concentration gradients to study chemotaxis.

Aminoisobutyric Acids↗
PubMed1980

One month of sustained release of insulin from a polymer implant.

Rats made diabetic with streptozotocin received a single subcutaneous implant of an insulin polymer pellet that released insulin continuously at approximately 2 U/day. Continuous normoglycemia was achieved for up to 1 mo. Mean glucose level for treated animals was 113 mg/dl as compared with 398 mg/dl for untreated diabetic controls. Diurnal blood glucose values for treated animals ranged from 71 to 116 mg/dl. Polyuria and glycosuria were corrected by the presence of the insulin + polymer. Treated animals gained weight normally and reached a mean weight of 350 g, whereas untreated control animals lost weight, to a mean of 150 g. When insulin + polymer preparations were periodically implanted and removed at 7-day intervals, normoglycemia was only associated with the presence of implants.

Animals↗
PubMed1980

Stromal vascularization prevents corneal ulceration.

Experiments were performed with a model of focal, thermal-induced ulceration to test the clinical impression that vascularization prevents ulceration of the corneal stroma. Slow-release polymers containing a vasoproliferase agent (tumor angiogenesis factor) were placed in corneal pockets 2 mm central to the limbus of albino rabbits. These polymers elicited blood vessel ingrowth up to the implant. Control eyes received empty polymers which caused minimal to no vessel growth. Polymers were removed, and each cornea received a focal, thermal burn placed just central to the polymer site. All control corneas ulcerated: most (79%) developed deep stromal or perforating ulcers. Only 25% of prevascularized corneas developed stromal ulcers, and none was deep or perforating. After thermal burns, vessels in both groups grew at the same linear rate toward the burned area. There was a direct relationship between the distance separating the nearest blood vessel and the burned area at the time of burning and the maximum depth of stromal ulceration. Thus prevention of or less severe stromal ulceration is correlated with the earlier presence of vessels in the burned area.

Angiogenesis Inducing Agents↗
PubMed1980

[Arterial vascular scleroses in the mammogram (author's transl)].

From 1974 to April 1979 5571 mammographies were made in the Department of Radiology of the University of Ulm. In 319 cases (5,7 %) we observed calcifications of the mammarian arteries. The incidence of arterial calcifications in mammography in patients up to 60 years of age was higher than coronary calcifications could be diagnosed by chest fluoroscopy or in an autopsy series by other authors. As the small mammarian arteries show an equal histological structure as the coronary arteries, they must show the same type of calcification. Therefore we consider that calcifications of the mammarian arteries could be a sign of general atherosclerosis.

Adolescent↗
PubMed1980

[Radiological diagnosis of fibulo-talar ligamentous lesions (author's transl)].

Of 343 patients with sprained ankles the results of conventional stress a.p. roetgenograms in supination and stressed X-rays in lateral view with a device, similar to the technique, described by Noesberger, are compared. In 63 of 91 pathological findings the lesions could only be diagnosed in X-rays in lateral view. The advantages and disadvantages of both techniques are discussed. In our opinion the stressed X-rays in lateral projection are a useful method for diagnosis of ligamentous lesions of the ankle joint.

Adolescent↗
PubMed1980

[Value of the direct X-ray magnification technique for the assessment of the therapeutic success in osteochondrosis dissecans in the knee-joint (author's transl)].

The article demonstrates the diagnostic value of the direct x-ray enlargement technique, taking a group of 11 patients with osteochondrosis dissecans of a femoral condylus as an example. The method is unsuitable as a diagnostic screening method, since the informative content of the enlarged roentgenograph, is greater in a defined area only, and since the additional exposure burden should not be overlooked, especially in the patients in question, who are mostly relatively young. However, the direct radiological enlargement technique is well suited for postoperative follow-up, since it is only with the help of visualization of the increasing trabecular bone bridges between femoral condylus and dissecate, that the process of incorporation can be visualized and hence also judged in respect of its success.

Evaluation Studies as Topic↗
PubMed1980

[Early manifestation of a radiation-induced fibro-angio-myxosarcoma within an irradiation field for Hodgkin's disease (author's transl)].

The case of a fibro-angio-myxosarcoma within an irradiation field for Hodgkin's disease is reported (TD = 4025 rad). In comparison with other cases published in literature, the latent period of 4 years 10 months was relatively short. Radiation-induced sarcomas generally are observed in the irradiation field not earlier than after a free interval of 10 or 12 years, and with focal doses above 4000 rad.

Adult↗
PubMed1980

[Tolerance of the contrast medium ioxaglinic acid in angiographic examinations. A clinical study (author's transl)].

Within the framework of a clinical study, subjective and objective data were compiled on the low-osmolar contrast medium ioxaglinic acid. In 213 angiographies performed on 134 patients in the Department of Radiology I of the Ulm University Clinic from October 1979 to February 1980, it was established that unfavourable subjective symptoms were missing to a major extent. Hence, we believe that it is not justified to subject the patients to the additional stress of general narcosis when performing peripheral and cerebral angiographies. In more than 50% of the patients, the contrast medium produced either an increase or a drop in blood pressure; a state of collapse requiring treatment never occurred in any of the patients.

Angiography↗
PubMed1979

[An unusual suicidal attempt (author's transl)].

Report on an unusual suicidal attempt by a separating disc (grinding disc). The patient inflicted himself incisions on both wrists, the occiput and the throat between the hyoid-bone and the thyroid cartilage. The hypopharynx was severed up to the posterior wall and the left jugular vein was cut completely. Due to the immediate care by the physician, the patient survived.

Adult↗
PubMed1979

Erythema nodosum associated with pregnancy. Case reports.

Four cases of erythema nodosum associated with pregnancy are reported and the literature reviewed. Erythema nodosum in pregnancy is a self-limited condition requiring minimal supportive treatment. No adverse effects upon pregnancy course or fetal outcome were noted. It is suggested that pregnancy may serve as an etiological basis for the disease.

Adult↗
PubMed1979

[Angiographic features of liver echinococcosis (author's transl)].

From 1973 to 1978 13 cases of cystic hydatid disease and 15 cases of alveolar hydatid disease of the liver were diagnosed by angiography. The main diagnostic features of cystic hydatid disease of the liver are the following: "rim-sign", avascular areas, curved displacement of the arteries and stretching of the intrahepatic arteries. Multilocular hydatid disease of the liver shows tumor-like angiographic signs, such as atypical vascular formations, distensions, vascular irregularities, arterial stenoses as well as hepatosplenomegaly. Differential diagnosis in malignant liver diseases is often impossible, but early venous filling and arteriovenous shunts are not characteristic of multilocular hydatid disease of the liver. Particularly difficult is the interpretation in patients who have had previous surgery.

Adult↗
PubMed1979

Conservative surgery for tubal pregnancy.

Twenty-four conservative surgical procedures for unruptured tubal pregnancies were performed on 23 patients with poor past obstetric performance. All cases were diagnosed preoperatively by laparoscopy. Salpingotomy was performed in 20 cases and fimbrial expression of the ectopic pregnancy was performed in 4 cases. In the group of conservatively treated patients there were 15 live births in 11 women and 28 intrauterine pregnancies in 14 women. No ectopic pregnancies occurred in the operated tube. Early diagnosis and conservative surgical treatment of unruptured tubal pregnancy is appropriate for patients with poor reproductive histories.

Adnexal Diseases↗