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Biomedical subjects

R Berg

Publications and source records attributed to R Berg.

At least 91 records · Page 5Linked to original sources
PubMed1992

Effects of optical constants on time-gated transillumination of tissue and tissue-like media.

Light transillumination was used to study structures inside turbid media. Time-gated viewing was performed to suppress multiply-scattered light and thus improve spatial resolution. We demonstrate that, for the case of scattering-dominated attenuation (scattering coefficient much greater than the absorption coefficient), the detection of early transmitted light will be practically insensitive to variations in the absorption coefficient. This is an important observation for the development of time-gated optical mammography, since optical mammography using continuous-wave light is based on increased light absorption in the tumour region caused by the neovascularization surrounding a tumour. In order to detect tumours in time-gated viewing it is the scattering coefficient of the tumour that must be characteristic. The scattering coefficient is measured to be lower in the tumour region than in the surrounding breast tissue for one resected breast specimen.

Female↗
PubMed1992

Influence of arterial access sites and interventional procedures on vascular complications after cardiac catheterizations.

The purpose of this study is to define the incidence of complications at the arterial access site after cardiac catheterization. The influence of the arterial access site on these complications was identified, as were the clinical characteristics of these problems. A total of 8,797 cardiac catheterizations were performed over the 3-year period of this study. Diagnostic catheterizations and percutaneous transluminal coronary angioplasties (PTCAs) were included, and the arterial access site was identified. Diagnostic catheterizations were performed via the brachial artery (group I, n = 3,137) or the femoral artery (group II, n = 4,055). PTCAs were also performed via the brachial artery (group III, n = 32) or the femoral route (group IV, n = 1,573). Ninety-five major vascular complications occurred during the course of this study. The frequency of complications was higher with brachial artery catheterization when compared with the femoral route. PTCA was associated with a higher complication rate than diagnostic studies. Brachial artery complications were primarily arterial thromboses, which were easily diagnosed and treated. Femoral artery complications were more complicated, difficult to identify, and associated with significant morbidity.

Angioplasty, Balloon, Coronary↗
PubMed1991

How mental health providers see managed care.

This paper reports findings from two focus groups on managed care conducted in a large U.S. city in 1989. Questions addressed included how managed care had affected mental health practice, specific experiences with managed care, the mechanisms of managed care, and how managed care could be improved. The practitioners complained of multiple problems, but clearly distinguished between "good" and "bad" firms. Firms seen as more positive struck a balance between quality care and cost containment, built ongoing relationships with providers, and negotiated with providers, rather than prescribing a treatment plan. The authors conclude that some of the poor reception by providers of managed care may have been created unnecessarily by firms which have not attended to these factors, and that attention to such factors might lead to a more ready acceptance of managed care.

Attitude of Health Personnel↗
PubMed1991

Evaluation of orthodontic results--a discussion of some methodological aspects.

The informative value of clinical material presented at meetings and in the literature poses a dilemma for the typical orthodontist. To aid in the resolution of this problem, methodological aspects of the following topics are discussed: criteria for the evaluation of orthodontic treatment results, the selection of cases to be evaluated, the presentation of orthodontic treatment results and the interpretation of case presentations. Orthodontic relapse should be considered to be a number of continuous variables affecting treatment results; different follow-up criteria should be employed when comparing pretreatment, posttreatment and postretention results.

Evaluation Studies as Topic↗
PubMed1991

Oral dysfunction in children with Down's syndrome: an evaluation of treatment effects by means of video registration.

The objects of the study were: (1) to analyse lip and tongue function in 24 children with Down's Syndrome as compared to an untreated control group of 19 healthy children; (2) to evaluate treatment effects of stimulation plates of the type Castillo Morales, in children with Downs' Syndrome. The range of the observation period during treatment was 4-11 months. Video recordings of 5 minutes (300 seconds) duration served as a basis for stop watch registrations of tongue protrusion and open mouth habit. Before treatment, the duration of tongue protrusion in the Downs' Syndrome group amounted to approximately half of the registration time as compared to an average of only 6.4 seconds in the control group. The values for lip closure differed only slightly. Following the insertion of the stimulation plate, the duration of tongue protrusion, in general, dropped markedly. No improvement in mouth closure or lip posture could be observed. A normalization of tongue function without the plate inserted was achieved after 4-11 months of treatment in 12 out of the 24 children. Follow-up registrations, ranging from 5 to 20 months, could be obtained in 7 out of the 12 successfully treated children. The results appeared to be stable in five of these children.

Child, Preschool↗
PubMed1991

[Pont's index--a discussion].

When comparing orthodontic textbooks from various countries Pont's Index appears to have played a relatively important role in Germany. In the USA a marked shift in treatment concept came up during the forties, in that the maintaining of pre-treatment dental arch form--specifically in the lower jaw--now was considered to be important for reasons of stability. Later research findings have supported this concept. In view of present knowledge, strong doubts are expressed regarding the justification for the use of Pont's Index in clinical practice, in teaching as well as in communication with the Health Insurance.

Dental Occlusion↗
PubMed1990

Smooth muscle actin expression during P19 embryonal carcinoma differentiation in cell culture.

P19 embryonal carcinoma (EC) cells can be induced in vitro to differentiate into cells resembling those normally formed in the embryo. Among these cell types is one whose morphology is fibroblast-like. Using indirect immunofluorescence and Western blot analysis with antibodies directed against various isoforms of actin, many of these fibroblast-like cells were found to express smooth muscle actin isoforms. Northern blot analysis of RNA indicated the presence of a smooth muscle-specific isoform of myosin heavy-chain mRNA in immortal lines of these fibroblast-like cells. These results suggest that these fibroblast-like cells resemble fetal myofibroblastic or myoepithelial cells, which have a wide distribution during embryonic development.

Actins↗
PubMed1990

Obstructive jaundice promotes bacterial translocation from the gut.

Experiments were performed to determine if obstructive jaundice promotes the translocation of bacteria from the gastrointestinal tract to visceral organs. Three groups of mice were studied: control (n = 20), sham ligated (n = 28), and bile duct ligated (n = 33). The sham-ligated group underwent laparotomy and manipulation of the portal region, whereas the ligated group had their common bile ducts ligated. Seven days later, the mice were killed, their organs cultured, and the gastrointestinal tract examined histologically. The bilirubin levels of the ligated group (18.7 mg/dL) were elevated compared with the other groups (0.5 mg/dL) (p less than 0.05). The incidence of bacterial translocation was higher in the ligated (33%) than in the control (5%) or sham-ligated (7%) groups (p less than 0.05). Since bile is important in binding endotoxin and maintaining a normal intestinal microflora, cecal bacterial populations were quantitated. The cecal levels of gram-negative, enteric bacilli were 100-fold higher in the bile duct-ligated mice in which bacterial translocation occurred (p less than 0.05), indicating that intestinal bacterial overgrowth was a major factor responsible for bacterial translocation. The mucosal appearance of the intestines from the control and sham-ligated groups was normal. In contrast, subepithelial edema involving the ileal villi was present in the ligated group. In conclusion, the absence of bile within the gastrointestinal tract allows intestinal overgrowth with enteric bacilli and the combination of bacterial overgrowth and mucosal injury appears to promote bacterial translocation.

Animals↗
PubMed1990

Effect of hemorrhagic shock on bacterial translocation, intestinal morphology, and intestinal permeability in conventional and antibiotic-decontaminated rats.

Bacterial translocation and ileal and cecal injury have been shown to occur 24 h after limited periods of hemorrhagic shock. The present studies were performed to determine the temporal sequence of mucosal injury, permeability, and bacterial translocation after hemorrhagic shock. The results indicated that bacterial translocation and mucosal injury have occurred by 2 h after a 30-min episode of shock (mean arterial pressure 30 mm Hg). Although the histologic extent of the intestinal mucosal injury was less at 2 h postshock than at 24 h postshock, at both times intestinal barrier function was lost as measured by permeability to horseradish peroxidase. Since the role of translocating bacteria in potentiating the loss of intestinal barrier function after shock is unclear, the second goal was to determine whether the extent of shock-induced mucosal injury and permeability could be reduced or abrogated by antibiotic decontamination of the gut. The extent of shock-induced mucosal injury and intestinal permeability was similar between rats with a normal gut flora (greater than 10(6) bacteria/g cecum) and antibiotic-decontaminated rats (less than 10(3) bacteria/g cecum) 2 h postshock, although the incidences of bacterial translocation were 67% and 0, respectively. Thus, shock-induced mucosal permeability and injury appear not to be directly related to the presence of translocating bacteria.

Animals↗
PubMed1990

Hemorrhagic shock-induced bacterial translocation: the role of neutrophils and hydroxyl radicals.

We previously documented a relationship between xanthine oxidase activation, intestinal injury, and bacterial translocation (BT) in rats subjected to hemorrhagic shock. The current experiments were performed to determine the relative roles of hydroxyl radicals and neutrophils in the pathogenesis of shock-induced mucosal injury and BT. The incidence of BT was higher in the shocked rats (30 mm Hg for 30 min) than the sham-shock controls (87% vs 12.5%; p less than 0.01). Administration of the hydroxyl radical scavenger, dimethyl sulfoxide (DMSO), or the iron chelator, deferoxamine, reduced the incidence of BT from 87% to 20% and 40%, respectively (p less than 0.05). DMSO and deferoxamine appear to prevent shock-induced BT by blunting the magnitude of shock-induced mucosal injury. In contrast, neutrophil depletion did not prevent BT or protect the intestinal mucosa in shocked rats. Instead, the incidence of systemic spread of translocating bacteria past the mesenteric lymph nodes to the livers and spleens of the shocked rats was higher in the neutrophil-depleted rats (56%) than in any other group (p less than 0.01). Thus, shock-induced BT and intestinal injury appear to be mediated by oxidants (.OH) derived from xanthine oxidase, rather than granulocytes.

Animals↗
PubMed1990

A double-blind comparison of naproxen gel and placebo in the treatment of soft tissue injuries.

A double-blind study was carried out in 120 patients who had received soft tissue injuries within the preceding 48 hours to compare the effectiveness of naproxen gel (10%) with placebo gel (base alone). The injuries were predominantly synovitis and tendinitis. Standard clinical evaluations of the patients' condition were made by physicians and patients on entry and after 3 and 7 days of treatment. Both treatments resulted in a significant improvement in symptoms, but naproxen gel was significantly superior to placebo gel (p less than 0.05). The response produced by naproxen was more rapid; all symptoms were significantly improved by Day 3 (p less than 0.05). The greater efficacy of naproxen was reflected in a lower usage of active drug compared with placebo which was consistent throughout the study. While the physicians' global assessments of the two gels did not differ significantly, the patients showed a preference in favour of naproxen (p less than 0.05) Naproxen gel was well tolerated; only 1 adverse event of itching occurred. It is suggested that naproxen gel offers an effective and convenient alternative to systemic non-steroidal anti-inflammatory drugs for patients where side-effects are to be avoided or when oral administration is undesirable.

Adolescent↗