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This paper presents a critical review of studies that apply life-cycle assessment or life-cycle-based environmental analysis methods to geotechnical systems. The goal of this review is to evaluate the current state of practice for life-cycle assessment in geotechnical engineering and to identify critical gaps in current practice and key issues for future research efforts. Additionally, this review examines sources of variability and uncertainty across the studies and provides recommendations for best practice in future assessments. Aside from challenges in creating a practicable framework, many barriers to implementation exist – including the availability of region-specific data, the quality and granularity of data and challenges in comparing geotechnical systems due to spatial heterogeneity and design decisions, among others. Further research is needed to develop guidelines for life-cycle assessments tailored to geotechnical systems to establish common criteria and methods for future studies.

Background. Autoimmune hepatitis (AIH) and cryptogenic chronic hepatitis (CCH) are important causes of liver failure in children, frequently necessitating orthotopic liver transplantation (OLT). The aim of this study is to review disease progression and potential differences between subgroups of children with AIH and CCH. Methods. The medical records of 65 children diagnosed with AIH or CCH between 1980 and 1998 were evaluated. Results. The median age at presentation was 9 years, 8 months (range 4 months-19 years), and the median follow-up period was 8 years (range 3 months-18 years, 10 months). Forty-one patients (63%) were female. Twenty-eight patients were Hispanic, 28 were Caucasian, 8 were African-American, and 1 was Asian. Forty-three patients (66%) were diagnosed with type 1 AIH, 8 (12%) with type 2 AIH, and 14 (22%) with CCH. Forty patients (62%) underwent OLT (51% of those with type 1 AIH, 75% of those with type 2 AIH, and 86% of those with CCH). Thirteen (33%) of the transplanted patients experienced disease recurrence. African-American patients experienced a significantly higher rate of disease recurrence post-OLT than did Hispanic patients. Seven patients (11%) died, two without OLT, and five posttransplantation. Conclusions. AIH and CCH frequently necessitate OLT in children. CCH is a more aggressive disease than Type 1 AIH among children with these disorders. Ethnicity influences the rate of disease recurrence after liver transplantation.

The safety of steroid withdrawal in orthotopic liver transplant (OLT) recipients has been studied in a prospective trial with a comparison control group. Sixty-four recipients of ABO-compatible grafts (42 adults, 22 children) were randomized into a steroid withdrawal (SW) group and a control group. Inclusion criteria included survival > one year post-OLT and no rejection > six months after OLT. Exclusion criteria included previous graft loss secondary to rejection, > two episodes of documented rejection, patients transplanted for autoimmune hepatitis, and patients unable to receive azathioprine. Target HPLC cyclosporine levels in both groups were 100-200 ng/ml. Thirty-three patients entered the SW group and 31 the control group at a mean of 3.5 years after OLT; follow-ups were 592 and 527 days, respectively. Two patients in each group developed biopsy-proven rejection. In the SW group one patient rejected at three months, the other at nine months. Both rejection episodes resolved with only reinstitution of oral prednisone. Of the two patients who rejected in the control group (one at 7 months, one at 11 months) one required conversion to tacrolimus and the other intravenous steroids. There were no significant differences between the two groups for prednisone, azathioprine, cyclosporine doses, cyclosporine levels, liver function tests, and white blood cell counts at base line compared with 12 months. Fasting serum cholesterol in the SW group decreased from 194 +/- 44 mg/dl at baseline to 175 +/- 37 mg/dl at one year, whereas in the control group cholesterol rose from 180 +/- 48 mg/dl to 193 +/- 44 mg/dl. In pediatric patients no significant difference in age-adjusted height velocities over one year was seen between the two groups. We concluded that dual therapy with cyclosporine and azathioprine in stable long-term liver allograft recipients is not associated with an increase in rejection incidence. Prednisone withdrawal may be associated with an improvement in lipid profiles.

The effects of three isocaloric intravenous nutritional regimens were studied in seven infants and children, ages 2 months to 9 yr, with congenital gastrointestinal anomalies (four patients) or with prior history of malignant disease admitted in remission for bone marrow transplantation (three patients). Energy metabolism, as measured by the basal metabolic rate (BMR), and substrate utilization, as measured by the respiratory quotient (RQ), were studied to determine the effect of different levels of carbohydrate and fat on nitrogen retention in each patient. Solution A provided 8% of energy as amino acids, 87% as carbohydrate, and 5% as fat. Solution B provided 8% of energy as amino acids, 60% as carbohydrate, and 32% as fat. Solution C provided 8% of energy as amino acids, 34% as carbohydrate, and 58% as fat. Administration of solution A (high carbohydrate, low fat) was associated with moderately increased mean (+/- SD) BMR and RQ and with low nitrogen retention (19.1 +/- 12.7%, 1.06 +/- 0.14, and 98 +/- 28 mg N/kg/day). Both the BMR and the RQ decreased when less carbohydrate and more lipid was given: BMR 4.3 +/- 11.6% (p less than 0.005), RQ 0.92 +/- 0.09 (p less than 0.001) for solution B; BMR 3.94 +/- 10.6% (p less than 0.005), RQ 0.86 +/- 0.09 (p less than 0.001) for solution C. Among the solutions tested, optimal nitrogen retention [163 +/- 60 mg N/kg/day (p less than 0.01)] was noted with solution B. Our data support the conclusion that a physiologic balance of fat and carbohydrate results in optimal nitrogen retention.