Biomedical subjects

V Chen

Publications and source records attributed to V Chen.

129 records · Page 8Linked to original sources

PubMedDate not supplied

An improved isolated working rabbit heart preparation using red cell enhanced perfusate.

The performance of isolated working rabbit hearts perfused with Krebs-Henseleit (KH) buffer was compared with those in which the buffer was supplemented with washed human red blood cells (KH + RBC) at a hematocrit of 15 percent. When perfused with KH alone at 70 cm H2O afterload and paced at 240 beats/minute, coronary flow was more than double, whereas aortic flow was 40-60 percent of that in hearts perfused with KH + RBC, regardless of left atrial filling pressures (LAFP). Peak systolic pressure reached a plateau at 120 mm Hg in KH + RBC, but at 95 mm Hg in the KH group. Stroke work, however, was similar in the two groups. Despite the high coronary flow, oxygen uptake by hearts perfused with KH was substantially less and did not respond to increases in LAFP as in those perfused with KH + RBC. There was a 20 percent drop in ATP and glycogen content after 90 minutes' perfusion. In contrast, isolated hearts perfused with RBC-enriched buffer remained stable for at least 150 minutes. Irrespective of the perfusate, triacylglycerol content of the muscle remained at similar levels throughout the course of study. Increasing RBC in the perfusate from 15 percent to 25 percent had no additional effect on cardiac performance or oxygen consumption. Our findings demonstrate that in the isolated working rabbit heart inclusion of RBC in the perfusate improves mechanical and metabolic stability by providing an adequate oxygen supply.

Animals↗

PubMedDate not supplied

The effect of alcohol on the risk of lung cancer in Uruguay.

A hospital-based case-control study of the association between alcohol drinking and lung cancer was carried out in Uruguay between January 1988 and December 1990. The sample included 327 men with lung cancer and 350 male controls. Personal interviews were conducted in the Institute of Oncology by trained personnel using a structured questionnaire. The results showed a significant positive association between beer intake and the risk of lung cancer. The odds ratio for beer drinkers in the highest quartile was 3.4 (95% confidence limits, 1.3-6.6) after adjustment for tobacco. The association between beer and lung cancer was consistent for all the cell types, analyzed separately. A moderate effect for total alcohol consumption was also observed, with a relative risk of 2.2 for those subjects in the highest quartile.

Adenocarcinoma↗

PubMedDate not supplied

Four-incision radial keratotomy for high myopia after penetrating keratoplasty.

BACKGROUND: High amounts of myopia can frequently produce anisometropia and limit visual rehabilitation by conventional means in eyes with clear corneal grafts. This condition is frequently coupled with large amounts of astigmatism. Four-incision radial keratotomy provides a way to reduce myopia in normal individuals. In our present study, we used the technique of four- incision radial keratotomy to reduce myopia in a group of keratoplasty patients who failed conventional visual rehabilitation. Arcuate or transverse keratotomy was used in conjunction with radial keratotomy in eyes with high amounts of astigmatism. METHODS: This study retrospectively examined a group of 11 eyes with penetrating keratoplasty which underwent four-incision radial keratotomy for the treatment of visually disabling myopia. The radial incisions were placed in the graft, inside the graft-host interface. Seven eyes underwent concomitant arcuate relaxing incisions at the graft-host interface for treatment of associated astigmatism. One additional eye had paired straight transverse incisions for the treatment of astigmatism. The mean postoperative follow up was 16 months (range, 3 months to 5 years). RESULTS: There was a mean reduction of the spherical equivalent refraction of 3.48 diopters (D) (range, 0.25 to 7.75 D). The eight eyes undergoing astigmatic surgery showed a mean reduction in keratometric astigmatism of 2.25 D (range, -6.75 to +6.50 D) and refractive astigmatism of 4.63 D (range, -1.50 to -9.50 D). Nine of the 11 eyes had stable or improved best spectacle corrected visual acuity. Two eyes had reduction of best spectacle corrected visual acuity--one due to development of irregular astigmatism and one due to worsening of preexisting macular edema. CONCLUSIONS: Four-incision radial keratotomy can reduce myopia after penetrating keratoplasty when the patient is unable to tolerate spectacle or contact lens correction. It can be combined with relaxing incisions or transverse keratotomy to reduce astigmatism. There is a high amount of variability, and predictability is currently limited by the complex topographical changes occurring in corneal transplants. Complex corneal biomechanical changes may predispose these eyes to the development of irregular astigmatism.

Adult↗