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Biomedical subjects

R Winter

Publications and source records attributed to R Winter.

At least 19 recordsLinked to original sources
PubMed1992

Chronic hypoxia changes the ratio of endothelin to ATP release from rat aortic endothelial cells exposed to high flow.

Endothelial cells isolated from the thoracic aorta of normoxic and chronically hypoxic rats were perfused (0.5 ml min-1) and stimulated by increased flow rate (3.0 ml min-1). The release of ATP, endothelin and vasopressin was investigated. During periods of high flow rate, endothelial cells isolated from normoxic rats increased their release of ATP and endothelin. In comparison, in hypoxic rats, ATP release during the period of high flow rate was less, whereas endothelin release was greater. Vasopressin release was not increased during periods of stimulation in either group of animals. These results suggest that, under conditions of reduced arterial oxygen tension, a dynamic balance between ATP and endothelin release could regulate the response of vessels to shear stress.

Adenosine Triphosphate↗
PubMed1992

The effect of selective decontamination of the digestive tract on gastrointestinal enterococcal colonization in ITU patients.

OBJECTIVE: The effect of selective decontamination of the digestive tract (SDD) on Intensive Therapy Unit (ITU)-acquired enterococcal infection and colonization was studied. Changes in the predominant species isolated and resistance patterns to antimicrobial agents were also studied. DESIGN: Three groups were investigated: historical control (HC), contemporaneous control (CC) and patients receiving SDD (topical polymyxin, amphotericin B and tobramycin throughout ITU stay with intravenous ceftazidime for the first 3 days only). SETTING: Adult general ITU with 7 beds. PATIENTS: Patients with a nasogastric tube in situ and who were likely to remain in ITU for 48 h or longer were recruited. RESULTS: Enterococcal infections occurred in 3 of 84 HC patients and 2 of 91 CC patients. There were no unit-acquired enterococcal infections in the SDD group. There were 140 episodes of enterococcal colonization occurring in 112 patients, with significantly more in the SDD and CC groups (p < 0.05. There were no significant differences in antibiotic sensitivities between the three groups. Enterococcus faecalis was the most frequently isolated species. CONCLUSION: SDD does not predispose to enterococcal infection but does encourage colonization in patients receiving the regimen and other patients in ITU at the same. There is a complex interaction of factors which influence faecal flora and the likelihood of patients becoming colonized or infected with enterococci.

Administration, Buccal↗
PubMed1992

Falling spells associated with antidepressant drug treatment.

Six patients experienced falling spells concurrent with the intake of antidepressant drugs in high doses or in moderate doses combined with other psychotropic drugs. The close temporal correlation between drug ingestion and the falling spells and their immediate termination after reduction or discontinuation of medication suggests that these drugs caused the falls. Further factors predisposing to the falling spells remain to be defined.

Aged↗
PubMed1992

A controlled trial of selective decontamination of the digestive tract in intensive care and its effect on nosocomial infection.

Nosocomial infection is a major problem in intensive therapy units (ITUs) and a significant cause of mortality. Selective decontamination of the digestive tract (SDD) has been advocated as a means to reduce ITU morbidity and mortality. Ninety-one patients in a general ITU underwent SDD, consisting of topical polymyxin E, tobramycin and amphotericin B administered throughout the unit stay together with parenteral ceftazidime for the first three days, and were compared with 84 historical and 92 contemporaneous control patients who were treated conventionally. Twenty-seven historical and 32 contemporaneous control patients developed unit-acquired infections, in comparison with only three patients in the SDD group (P less than 0.01). Mortality in the SDD group (36%) was not significantly different from that in the other two groups (historical control 40%, contemporaneous control 43%). Screening specimens revealed a significantly higher rate of colonization with resistant Acinetobacter spp. in the contemporaneous control than in the other two groups of patients; infection caused by resistant bacteria did not occur. SDD did not lead to a significant reduction in the use of systemically-administered antibiotics when compared with either control group. SDD may be used selectively in an ITU without ill effects on those patients not receiving SDD; nevertheless, microbiological monitoring is needed to detect emergence of resistant bacteria in the unit.

Adolescent↗
PubMed1992

[Endothelial cell protective effect of high viscosity substances in cataract surgery].

An experimental setting is presented to evaluate the endothelial protection offered by various viscoelastic materials applied in cataract surgery. The substances used were: hydroxypropylmethylcellulosis, a hyaluronic acid preparation (molecular weight 5.10(6), concentration 10 mg/ml), a hyaluronic acid preparation (molecular weight 800 000, concentration: 35 mg/ml), and balanced salt solution as control. The endothelial surface of pig corneas were covered by test substances and spread with a loop of prolene 4.0 suture material in a mechanically standard way. A total of 40 corneas were examined and the amount of endothelial damage evaluated by photometry using Janus-green wash-out, a substance, which selectively binds to damaged endothelial cells or descement membrane. The damaged surfaces differed significantly in all groups of viscoelastic substances and in the control group. Examination showed that the least damage was in group 3, followed by group 1 and the most damage in group 2. Endothelial protection during cataract surgery can be improved by modifications of the substances presently applied.

Animals↗
PubMed1992

[Effect of postmortem duration on endothelial cell density in short-term culture with McCarey-Kaufman medium. An experimental study with Swine corneas].

It is recommended by the Eye Bank Association of American that the post-mortem time of donor tissue stored in intermediate storage should not exceed 6 h. In an experimental study we investigated the impact of post-mortem time on the storage of corneas kept in McCarey-Kaufman medium. Eyeballs of freshly slaughtered pigs were kept in moist chamber storage at 4 degrees C for 0, 6, 12, 24, and 48 h. Subsequently, corneal-scleral rims were dissected and stored in MK-Medium for 2 days at 4 degrees C. The corneas were stored in organ culture for another 2 days at 31 degrees C in MEM medium containing 10% fetal calf serum. A control group consisted of corneas that had been stored in organ culture for 2 days. Morphometric analysis revealed no significant changes in endothelial cell density compared to control corneas after up to 24 h of moist chamber storage prior to storage in MK medium. A significant decrease in endothelial cell density could only be detected in corneas that had been kept in moist chamber storage for 48 h before MK medium storage. We conclude that the recommendation that only donor corneas with short post-mortem times be used may exclude large amounts of potentially feasible tissue for penetrating keratoplasty.

Animals↗
PubMed1992

[Comparative studies of the use of viscoelastic substances in cataract surgery. A randomized study].

In three prospectively randomized groups of patients viscoelastic materials during IOL-implantation have been compared concerning 1. intraocular pressure, 2. endothelial cell count, 3. corneal thickness. Examinations were performed preoperatively, the first, second and fifth postoperative day. There was no statistical difference between hydroxypropylmethylcellulose (2%), hyaluronic acid (1%) and air. Examinations were performed preoperatively the first, the second and the fifth postoperative day. There was no statistically significant difference between all groups of patients, Advantages and disadvantages for routine use of viscoelastic substances are discussed.

Corneal Stroma↗
PubMed1991

The treatment of spinal kyphosis.

The modern management of kyphosis depends on the diagnosis, but there are common factors on which rational treatment can be based. An understanding of the biomechanics is very important, especially in planning operations on the spine. The greatest single advance has been the anterior approach. Scheuermann's disease in children is best treated by bracing, but most other deformities need anterior and posterior fusion. Modern instrumentation benefits both the patient and the surgeon.

Humans↗
PubMed1991

[Changes in the endothelial cell density after perforating keratoplasty].

We examined 590 endothelial photomicrographs of 327 patients with computerized morphometry; these patients had undergone penetrating keratoplasty in the period from 1981 to 1987. We found a weak negative correlation of r = -0.39 between postoperative endothelial cell density and the postoperative period. The endothelial cell density in the interval 12-24 months postoperatively averaged 1624 cells/mm. This is approximately 380 cells/mm more than described in other studies of that kind. We found significantly higher cell densities for cultured corneas and for corneas of young donors (age up to 39 years) up to 1 year postoperatively. Comparison of the diagnosis groups showed no relevant differences in postoperative cell density.

Cell Count↗