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Biomedical subjects

R Schaeffer

Publications and source records attributed to R Schaeffer.

14 recordsLinked to original sources
PubMed2001

[Multidisciplinary management of aortic dissection complicating pregnancy].

BACKGROUND: Most cases of aortic dissection observed in women under 40 years of age occur as a complication of pregnancy in patients with other risk factors. Case report. We report a case of dissection of the ascending aorta in a young primigravida at 35 weeks gestation. The risk factor was aortic regurgitation. Multidisciplinary management enabled fetal extraction followed by repair of the aorta. Outcome was favorable for both mother and child. DISCUSSION: A review of the literature shows a variety of etiological factors leading to this disease. Emergency diagnosis and management is mandatory. Obstetricians should be aware that pregnancy can be a triggering factor in patients with a predisposition, e.g. connective tissue disease. A complete cardiovascular evaluation should be conducted before conception and a suitable surveillance planned for the entire pregnancy. The aim of this careful follow-up it to avoid surgery in an emergency setting that could compromise prognosis for both mother and child.

Adult↗
PubMed2000

Nitrous oxide fraction in the carbon dioxide pneumoperitoneum during laparoscopy under general inhaled anesthesia in pigs.

UNLABELLED: During prolonged laparoscopy, the diffusion of other gases in the carbon dioxide (CO(2)) pneumoperitoneum may lessen its safety. Nitrous oxide (N(2)O)/CO(2) gas mixtures may become hazardous with regard to gas embolization and fire risk. We therefore evaluated the kinetics of pneumoperitoneal intrusion of N(2)O. In five anesthetized domestic pigs, controlled ventilation, with an initial fraction of inspired oxygen = 1.0, was adjusted to keep ETCO(2) pressure between 35 and 45 mm Hg. The peritoneum was insufflated with CO(2) to a pressure of 12 mm Hg, which was maintained throughout the procedure. T0 was defined as the time when N(2)O was introduced in the breathing circuit (N(2)O end-tidal fraction = 66%). Gas samples (10 mL) from the pneumoperitoneum were analyzed every 10 min after T0. The N(2)O concentration was measured by using capillary gas chromatography coupled with mass spectrometry. Percentages of N(2)O in the CO(2) increased with time (t) according to the ideal equation: N(2)O((t)) = 66 (1 - exp(-0.005t)). In the peritoneal cavity, <2 h were required for the N(2)O to reach the concentration of 29%, which can support combustion. Eight hours to 10 h after T0, the intraperitoneal N(2)O fraction approaches the level of the N(2)O end-tidal fraction. Options to prevent accumulation of N(2)O are suggested. IMPLICATIONS: Pig models were used to evaluate the time course of nitrous oxide (N(2)O) diffusion in the pneumoperitoneum during nitrous oxide/oxygen anesthesia. Although peritoneal N(2)O concentration approaches the end-expiratory value after 8-10 h, it reaches 29% within 2 h. At this level, N(2)O is known to support combustion. This N(2)O pollution should be prevented.

Anesthesia, Inhalation↗
PubMed1998

Flash pump dye laser treatment of laryngeal papillomas.

To evaluate the feasibility and safety of the flash pump dye (FPD) laser for the treatment of laryngeal papillomas, we performed a prospective nonrandomized trial comparing FPD and carbon dioxide (CO2) laser treatment of laryngeal papillomas in a tertiary care children's hospital. Nine patients from 2 to 20 years of age with severe recurrent laryngeal papillomas were enrolled in the study. All patients underwent CO2 laser debulking of papillomas on the left hemilarynx, with 8 W continuous or pulsed energy. The right hemilarynx was treated with the FPD laser with 12 to 77 pulses at 8 to 12 J, through a custom-designed 90 degrees firing fiber. An end point of blanching and purpura of the papillomas was used. The main outcome measures were the safety and ease of operation with the FPD laser, and decreased papilloma size based on visual inspection at 2 weeks postoperative and at the next laser procedure. Seven patients were irradiated I time with an FPD laser, and 2 patients 2 times. No intraoperative complications were noted. One patient developed early postoperative stridor. No patients described more discomfort, and 5 patients described their voice as being the same as or better than it was after prior CO2 laser procedures. Five patients had a 90% or more decrease in size of papillomas on the FPD-irradiated side 2 weeks postoperatively. Three patients had approximately a 50% reduction. A treatment effect was noted in all patients, and was similar to the results noted on the CO2 laser-treated side. Early results with FPD laser treatment of laryngeal papillomas suggest the protocol is relatively safe and feasible. Long-term results are pending. Because the FPD laser coagulates rather than vaporizing tissue, potential advantages may include decreased scarring relative to CO2 laser treatment, and improved patient and operator safety.

Adolescent↗
PubMed1991

Hyperparathyroidism presenting as an unusual cause of lower extremity gangrene.

Vascular surgeons are often consulted on the management of lower extremity ulcerations and gangrene which are commonly due to atherosclerotic arterial occlusive disease or to chronic venous insufficiency. The following report describes an unusual case of severe lower extremity cutaneous gangrene associated with secondary hyperparathyroidism and a review of the literature.

Amputation, Surgical↗
PubMed1991

[Emergency cesarean section].

Emergency cesarean section is a frequent high risk procedure. Systematic third trimester anesthesia consulation is of great value. The main problem is difficult intubation. It may be prevented by scoring patients according to Mallampati and Wilson, and by more frequent use of fiberoptic techniques. Perfect knowledge of a failed intubation drill is mandatory. Monitoring of ETCO2, SpO2 and curarisation comes in addition to basic monitoring. Special conditions as toxemia, major bleeding, allergies, maternal circulatory arrest are reviewed. Suggested protocols for general and locoregional techniques are presented.

Adult↗
PubMed1990

Immunopathological findings and thyroid autoantibodies in thyroid autonomy.

Different phenomena under consideration, lymphocytic and macrophagic infiltration and increased thyrocyte class I and class II antigen expression, normally ascribed to autoimmune thyroid disease (Graves' disease; Hashimoto's thyroiditis) were frequently found in thyroid glands with autonomous nodules, too. Contrary, nodular formations in the vast majority of nodular goiters were not associated with these immunopathological findings. Furthermore, thyroid microsomal, anti-peroxidase and TSH-receptor antibodies although at low frequency rates, were only detected in cases of autonomous nodules but not in cases of nodular goiters. From these findings we conclude that the immune phenomenon observed in thyroid autonomy could not be a consequence of nodular formations but that at least in some cases of thyroid autonomy immunopathogenic mechanisms may play an important role. Based on the fact that class I hyper-expression was more common and that a stronger correlation of cell infiltration with increased class I than with increased class II expression on thyrocytes existed we propose, that if the initial event of the autoimmune process is indeed increased class II expression, this stimulus may more likely originate from increased non-thyrocyte class II positivity (for example dendritic or endothelial cells) than from thyrocyte class II positivity. But, if aberrant class II expression is not the initial stimulus, another candidate could be the increased thyrocyte class I expression observed, probably due to the action of interferon alpha and/or beta induced by any unknown stimulus (viruses?).

Antibodies, Monoclonal↗
PubMed1986

[A new case of bronchospasm under extracorporeal circulation].

A case of bronchospasm occurring after the termination of cardiopulmonary bypass is reported. The complement fractions C3a, C4a and C5a were measured before and right after CPB. Complement activation is not specific to CPB but may occur in any thoracotomy. The statistically significant increase in complement C3a without any pulmonary symptomatology has been reported by several authors. Complement activation cannot therefore be considered as the explanation of this bronchospasm.

Bronchial Spasm↗
PubMed1983

Ouabain-like activity in human cerebrospinal fluid.

Human cerebrospinal fluid has been found to mimic the effect of ouabain on net Na+ efflux and 86Rb+ influx across erythrocyte membranes and on the in vitro activity of a purified Na+/K+-ATPase (ATP phosphohydrolase, EC 3.6.1.3) derived from canine kidney. These results indicate the possible existence in human cerebrospinal fluid of an endogenous factor with ouabain-like activity, which might be linked to sodium metabolism.

Biological Transport, Active↗
PubMedDate not supplied

Harry M. Vars Research Award. Glutamine enhances immunoregulation of tumor growth.

BACKGROUND: It is known that tumor progression is associated with a depletion in host glutamine (Gln) stores and a depression of natural killer (NK) cell activity. After demonstrating an in vitro dependence of NK cell activity on Gln and glutathione concentration, this study evaluated the effects of oral Gln on Gln and glutathione metabolism, NK cell activity, and tumor growth in the tumor-bearing rat. METHODS: Two days before tumor implantation, rats (n = 32) were randomized to receive Gln (1 g/kg/d) or an isonitrogenous amount of glycine by gavage and pair-fed food. On day 21 after tumor implantation, rats were killed, and tumors were measured and processed for glutaminase activity, glutathione content, and tumor morphometrics. Splenic lymphocytes were assayed for NK cell activity via a chromium (51Cr) release assay using YAC (NK-cell-sensitive mouse tumor cell line) target cells. Blood Gln and glutathione were measured. A second set of rats (n = 16) were treated similarly except that ketamine was given twice weekly to suppress NK cell activity. RESULTS: During the 3-week study period, tumor growth was decreased by 40% in the Gln group. This decrease in growth was associated with a 30% increase in NK cell activity. Administration of ketamine to rats completely reversed the higher NK cell activity and decreased the tumor growth seen in the Gln-treated group. CONCLUSIONS: These data indicate that oral Gln supplementation, through support of host Gln stores and glutathione production, may decrease tumor growth by enhancing NK cell activity.

Animals↗