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Biomedical subjects

L Casas

Publications and source records attributed to L Casas.

7 recordsLinked to original sources
PubMed1991

Design of two immobilized cell catalysts by entrapment on gelatin: internal diffusion aspects.

Experimental results obtained during the design of two immobilized cell catalysts by entrapment on gelatin are presented. Strong diffusional limitations are found and explained with the usual parameters and models, introducing an empirical correlation between substrate concentration and effectiveness factor. The effect of particle size, enzyme load, and specific activity in the system is discussed in terms of cooperation between bioengineers and geneticists.

Catalysis↗
PubMed1991

[The radiologic manifestations of bronchiolitis obliterans].

We reviewed the radiological findings in 19 patients suffering obliterans bronchiolitis, all of whom were classified as idiopathic obliterans bronchiolitis with organizing pneumonia. In most cases, above 80%, X-rays showed alveolar opacities in patches; other less frequent findings were the presence of an interstitial pattern and cavitation (10%). Radiological findings are not specific being most useful in posttreatment patient follow-up.

Adult↗
PubMed1989

The effect of acute hyperbaric oxygen therapy on axial pattern skin flap survival when administered during and after total ischemia.

The effect of hyperbaric oxygen (HBO) on axial pattern skin flap survival in male Wistar rats, when administered during and immediately following prolonged total flap ischemia, was evaluated. Eighty-one 3 x 6 cm rectangular epigastric skin flaps were elevated, and the inferior epigastric pedicle of each flap occluded for 8 hr. The animals were divided into a control and three other experimental groups: Control (n = 27) -8 hr flap ischemia, no HBO; Group (n = 21) - HBO therapy (100 percent O2--three 1.75 hr dives at 2.5 atm) during ischemia; Group 2 (n = 21) - HBO therapy (two 1.75 hr dives) following ischemia; Group 3 (n = 12) - HBO treatment during ischemia but with the flap contained in a metal-coated Mylar bag to prevent oxygen diffusion. The percentage of flap necrosis was calculated on postoperative day 6. Mean flap necrosis for controls was 28 percent (+/- 21 S.D.), while HBO treatment during ischemia or during reperfusion significantly reduced this necrosis to 9 percent (+/- 11) and 12 percent (+/- 14), respectively (p less than 0.01). The percentage of necrosis for Group 3, with the local with the local effect of HBO on the flap blocked by the diffusion barrier, was 5 percent (+/- 7), also significantly better than the controls (p less than 0.0005) but no different from the other two experimental groups. HBO treatment increases the percentage of axial pattern skin flap survival when administered during or immediately following total flap ischemia. The improved flap survival appears to be a systemic and not a local effect.

Animals↗
PubMed1989

Immediate breast reconstruction: reducing the risks.

One-hundred and sixty-five consecutive immediate breast reconstructions in 157 patients were reviewed. Reconstructions were performed with tissue expanders (53 percent) or immediate gel prostheses (47 percent). Immediate reconstruction was associated with an 18 percent rate of implant loss. Certain risk factors were identified at the p less than 0.05 level using immediate gel implants: failure to achieve complete muscle coverage of the implant, smoking at the time of surgery, initial gel implants of 400 ml or more volume, and age. Expander loss was increased by detaching the pectoralis major (p less than 0.05) and probably by lack of complete muscle coverage in general. Chemotherapy, history of previous smoking, and clinical stage of the carcinoma did not seem to affect reconstructive success. Smoking and patient age should be considered during patient selection for immediate reconstruction. Muscle coverage of the prosthesis should always be attempted. Muscle coverage is mandatory in the smoker. Gel implants of 400 ml or more volume are to be avoided at the initial operation. This approach should enable all surgeons to achieve lower rates of implant loss.

Adult↗