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Biomedical subjects

R Winter

Publications and source records attributed to R Winter.

At least 217 records · Page 12Linked to original sources
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↗
PubMed1991

Radicality of parametrial resection and dysfunction of the lower urinary tract after radical hysterectomy.

Sixty-six patients who underwent radical abdominal hysterectomy between 1971 and 1985 for stage Ib-IIb cervical cancer underwent urodynamic studies 1-15 years after surgery. None of the patients had received radiotherapy. Surgical specimens were processed as serial giant sections permitting measurement of the resected parametrial and paravaginal tissue. In 1984 parametrial resection was extended to the pelvic wall by the use of hemoclips. Impaired bladder sensation, bacteriuria, and residual urine were significantly more common among the patients who had more radical surgery, as were reduced flow rates and abnormal bladder compliance.

Female↗
PubMed1990

Potentiation of reperfusion-associated ventricular fibrillation by left ventricular hypertrophy.

Important electrophysiological alterations that may predispose hearts to arrhythmias have been described for hypertrophied myocytes, and hypertrophy coupled with ischemia has been associated with an increased incidence of sudden death; however, an influence of hypertrophy on reperfusion arrhythmias has not been previously described. We hypothesized that reperfusion-associated arrhythmias would be potentiated by left ventricular hypertrophy. After induction of renovascular hypertension, 37 awake, unsedated dogs (17 with left ventricular hypertrophy and 20 without hypertrophy) underwent 15 minutes of coronary artery occlusion and reperfusion. All dogs were pretreated with lidocaine bolus injections and with lidocaine by continuous infusion during coronary occlusion and reperfusion. Reperfusion-associated ventricular fibrillation occurred in seven of 17 dogs with left ventricular hypertrophy versus one of 18 dogs without hypertrophy (p less than or equal to 0.05). The presence of hypertension was not significantly associated with an increased incidence of reflow ventricular arrhythmias. Neither QT interval nor area-at-risk was different between the dogs with and without reperfusion ventricular fibrillation; however, increased heart rate just before reperfusion did correlate with an increased incidence of ventricular fibrillation at reperfusion. Thus, 1) left ventricular hypertrophy was associated with a significantly increased incidence of reperfusion-induced ventricular fibrillation after 15 minutes of ischemia, 2) this increased incidence was independent of the presence of hypertension, and 3) lidocaine protected control and hypertrophied hearts against ventricular fibrillation during ischemia but was ineffective in protecting hypertrophied hearts against reperfusion-induced ventricular fibrillation.

Animals↗
PubMed1990

Acalculous cholecystitis due to Salmonella virchow.

We report a case of systemic infection with Salmonella virchow in a 21-year-old male who subsequently developed acalculous cholecystitis. His symptoms and signs-resolved with parenteral antibiotics, as did the ultrasonographic findings in the gall bladder. To our knowledge, this is the first reported case of acalculous cholecystitis due to this serotype.

Acute Disease↗
PubMed1990

[Sacrococcygeal teratoma. Prenatal diagnosis and prognosis].

The routine use of ultrasonics during pregnancy allows an early diagnosis of a sacrococcygeal teratoma (SCT) with a high degree of certainty. The perinatal management is shown in a four case example prenatally diagnosed. The assessment of N-Acetylcholinesterase in the amniotic fluid in cases of cystic teratomas does not allow a safe differentiation from a myelomeningocele. A puncture of the tumor can be helpful for the verification of the diagnosis. Cells of all three germ layers may be found in the cytological fluid. The sonomorphological differentiation into solid and cystic tumors may play a significant role for the intrauterine growth. Even when diagnosed very early, cystic tumors do not compromise the intrauterine growth. Large solid tumors may lead to hydrops fetalis and intrauterine death. Furthermore, the prognosis depends on concomitant malformation as well as on the intracorporal spreading of the tumor. Therefore, a careful ultrasonic examination allows a good prenatal prognosis as to the severity of the malformation. Delivery is done by caesarean section in cases of large cystic-solid tumors. Small teratomas as well as most cystic tumors allow vaginal delivery after having been punctured previously.

Adolescent↗
PubMed1989

High-pressure small-angle neutron scattering (SANS) study of 1,2-dielaidoyl-sn-glycero-3-phosphocholine bilayers.

Small-angle neutron scattering of the trans-unsaturated DEPC has been investigated as a function of pressure at 12, 18.6 and 35 degrees C. A pressure-induced structural phase transition from a liquid-crystalline state to a gel state is observed at the temperatures studied. The critical pressure of this transition increases with increasing temperature with a delta P/delta T value of 51 bar/C degrees. The small-angle neutron scattering results indicate that the effect of the trans double bonds in DEPC is to enhance the conformational disorder in the hydrocarbon chains. In DEPC bilayers, a pressure-induced conformational ordering process is observed not only in the liquid-crystalline phase but also in the gel phase, which indicates that conformational disorder exists in the liquid-crystalline phase as well as in the gel phase.

Fatty Acids, Unsaturated↗