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Biomedical subjects

R Langer

Publications and source records attributed to R Langer.

At least 613 records · Page 34Linked to original sources

Ultrasonographic measurement of fetal growth parameters for estimation of gestational age and fetal weight.

The present study was undertaken to establish accurate, convenient, simple and rapid ultrasonographic measurements of fetal parameters and their correlation with gestational age and fetal weight. Relationship with gestational age was studied in 60 fetuses from 348 measurements of the biparietal diameter (BPD) and was also correlated with eight other parameters. There is no doubt that the BPD is the most reliable parameter for estimation of gestational age. In 34 infants, 306 measurements of nine fetal parameters taken within four days before delivery were correlated with their birth weights. Abdominal area gave the highest correlation, compared with other parameters or their combinations. Since combined measurements of several parameters gave only a slightly higher multiple correlation (R = 0.89) with fetal weight than the measurement of abdominal area alone (r = 0.85), their use is not justified as a routine procedure.

Body Weight↗

Angiogenesis capacity as a diagnostic marker for human eye tumors.

Solid tumors have the capacity to continuously stimulate the proliferation of new capillaries. Aliquots (0.1 cc) of aqueous humor were aspirated from the anterior chamber of the eye of 38 patients undergoing elective ophthalmologic surgery. The material was lyophilized and then inplanted on the chorioallantoic membrane (CAM) of 10-day-old chick embryos for bioassay. The angiogenesis capacity of each sample was graded as negative or positive. Nine of 10 patients with histologically proven retinoblastoma had positive vascular responses. Seven of 11 patients with choroidal malignant melanoma had a positive response to their aqueous humor on the CAM. Aqueous samples from eyes with an iris and ciliary body malignant melanoma and a metastatic breast carcinoma to the iris had a positive angiogenic response. By contrast, only one of 15 patients undergoing operation for cataracts, glaucoma, or other nonmalignant ocular disease showed an angiogenesis response. The one patient who a positive assay later developed lymphocytic leukemia. These studies show that certain intraocular tumors display angiogenesis capacity before clinically evident neovascular changes of floating tumor cells are seen. Patients without tumors showed no angiogenesis response.

Angiogenesis Inducing Agents↗

A case of listeriosis in pregnancy with fetal survival.

Listeriosis during pregnancy is generally considered to result in an intrauterine infection which affects the fetus before birth or in the perinatal period. A case of listeriosis in a 38-yr-old diabetic woman with an influenza-like disease in her 32nd wk of pregnancy is presented. Two successive blood cultures were positive for Listeria monocytogenes type 4b and her serum showed a rising titer for agglutinins to this organism. After antibiotic treatment of the patient she gave birth to a healthy child.

Adult↗

Continuous long-term intra-arterial infusion in the unrestrained rabbit.

A technique for the catheterization and intra-arterial infusion of the common carotid artery of the rabbit utilized a simple swivel apparatus, an acrylic head mount, and a silicone rubber sleeve. This method was used for continuous intra-arterial infusion in 29 unrestrained rabbits for periods up to 61 days.

Animals↗

Inhibition of neovascularization by an extract derived from vitreous.

An extract of the vitreous body, inhibited the growth of new blood vessels induced by tumors in the rabbit cornea. This extract was delivered by an inert, continuously releasing polymer. The average vessel growth rate in the region surrounding the polymer was 32% less in corneas containing the inhibitory substance than in control corneas.

Animals↗

Isolations of a cartilage factor that inhibits tumor neovascularization.

A cartilage fraction isolated by guanidine extraction and purified by affinity chromatography inhibits tumor-induced vascular proliferation and consequently restricts tumor growth. This fraction contains several different proteins; the major one has a molecular weight of about 16,000. The fraction strongly inhibits protease activity.

Carcinoma↗

Isolation of Mycoplasma from the placenta after cesarean section.

Placentas obtained at cesarean section were cultured for Mycoplasma and other microorganisms in 123 randomly selected patients in order to evaluate the incidence of Mycoplasma, to identify factors which may contribute to their presence, and to correlate their presence with the occurrence of postpartum infection. Twenty-eight placentas (22.8%) yielded Mycoplasma positive cultures. The incidence of Mycoplasma in the placenta was significantly higher in patients with ruptured membranes. The incidence of postpartum fever was significantly higher (P less than 0.01) in cases positive for Mycoplasma as compared to cases in which the placenta was negative for Mycoplasma. Findings were similar for both groups with regard to the incidence of unexplained postpartum fever. The results of this study suggest that Mycoplasma may be considered a relatively frequent pathogen and should be considered a possible cause of postpartum fever.

Cesarean Section↗

[Water disinfection by means of chlorine: killing of aggregate bacteria (author's transl)].

Rising water demands ask for an increasing utilization of more or less contaminated surface water that has to be chlorinated prior to treatment. Especially during periods of lake bloom, the desired disinfecting effect is not achieved in spite of high concentrations of chlorine present. This is due to a coating of bacterial surfaces by substances such as algal products having a protective effect as demonstrated in experimental studies by the authors. Bacteria in a central position within bacterial aggregates as e. g. formed by the addition of flocculants in the process of water treatment, are also protected against the action of chlorine. In cases of inadequate filter backwashing, such aggregates may penetrate into clean water. Accumulations of bacteria in the shape of widespread growth may also form on activated carbon filters, ion exchangers, at walls of tanks under unfavourable hydraulic concitions, and in stagnant parts of supply pipes. Curves depiciting the kill of dyspectic E. coli differentiated by O-agglutination and S. anatum were exhibiting longer survival periods as compared with non-aggregate bacteria. For organisms differentiated by H-agglutination, kill was between these values. The killing rate was found to be a function of the oxidation-reduction poteential. Furthermore, survival times for E. coli and S. anatum were found to be different. It has been confirmed by these experiments that chlorine concentrations as common in the practice of water works frequently do not suffice to kill bacteria within aggregates and that a colony count does not permit conclusions as to the bacterial count if bacterial aggregates are present.

Agglutination↗