Biomedical subjects

Bing Ho

Publications and source records attributed to Bing Ho.

2 recordsLinked to original sources

PubMed2006

Adaptive hyperfiltration in the aging kidney after contralateral nephrectomy.

We examined the magnitude of adaptive hyperfiltration in the remaining kidney of 16 aging (>57 yr) and 16 youthful (<55 yr) individuals who had undergone a contralateral nephrectomy. Healthy volunteers who were youthful (n = 143) or aging (n = 37) provided control values for the binephric condition. One-kidney glomerular filtration rate (GFR; +42%), renal plasma flow (+38%), plasma oncotic pressure (+2.8 mmHg), and mean arterial pressure (+7.0 mmHg) were all higher in youthful uninephric vs. binephric subjects. Corresponding excesses in aging uninephric vs. binephric subjects were by 38 and 36% and 1.4 and 14.0 mmHg, respectively. Modeling of these data revealed that an isolated increase in either the glomerular ultrafiltration coefficient (K(f)) by 110% or in the transcapillary hydraulic pressure gradient (DeltaP) by 7 mmHg, could account for the observed level of hyperfiltration in youthful uninephric subjects. Corresponding increases for aging uninephric subjects were 61% for K(f) and 5 mmHg for DeltaP. We conclude that the magnitude of adaptive hyperfiltration is similar in aging to that in youthful uninephric subjects, albeit at a lower absolute GFR level. Isolated increases in either K(f) or DeltaP or a combination of smaller increases in both can account for the hyperfiltration. Greater adaptive arterial hypertension in aging than youthful uninephric subjects raises the possibility of a disproportionate role for glomerular hypertension and DeltaP elevation in aging compared with youthful uninephric subjects. Glomerular hypertension could exacerbate the sclerosing glomerulopathy of senescence and lead to renal insufficiency. We recommend that living donors of a kidney transplantation in or beyond the seventh decade be used with caution.

Adaptation, Physiological↗

PubMed2003

Serial measurements of bone density at the lumbar spine do not predict fracture risk after liver transplantation.

Bone disease has emerged as a serious and complex complication after liver transplantation. The purpose of this study is to determine risk factors for fracture and bone loss after liver transplantation. Dual-energy x-ray absorptiometry (DEXA) of the lumbar spine was performed routinely pretransplantation, 6 months posttransplantation, and at yearly intervals thereafter at our center. We followed up patients who underwent transplantation in the past 10 years and compared bone mineral density (BMD) and fracture rate with known risk factors for bone loss in primary transplant recipients who met the inclusion criteria of a pretransplantation DEXA and at least one follow-up DEXA scan postoperatively (n = 153). We observed a 15% (n = 23) prevalence of symptomatic fractures at a mean of 2.2 +/- 1.8 years after transplantation. Change in BMD was greatest from pretransplantation to 6 months posttransplantation (-4.2%; P =.006), then increased at a rate of 1.4% per year. Logistic regression analysis showed an association of fracture risk with several factors, including number of acute rejection episodes (P =.045), smoking (P =.02), and female sex (P =.02). Stepwise logistic regression analysis reported female sex (P =.004) as the only factor associated with fracture after transplantation. Age, time listed for transplantation, race, menopause, chronic renal insufficiency, loss of height, family history of osteoporosis, BMD, and T score did not predict fracture or bone loss after transplantation. In conclusion, serial measurements of BMD at the lumbar spine do not appear to predict fracture risk; however, data suggest that female sex is the strongest predictor of fracture after liver transplantation.

Adult↗