Serial biopsies

In this chapter, our intent is to review the rapid changes that take place in the cerebral cortex of n-3 fatty acid-deficient monkeys when their diet is subsequently supplied with ample dietary n-3 fatty acids. Juvenile rhesus monkeys who had developed n-3 fatty acids deficiency since intrauterine life were repleted with a fish-oil diet rich in n-3 fatty acids, DHA, and 20 5n-3 (eicosapentaenoic acid, EPA). The fatty acid composition was determined for the lipid classes of plasma and erythrocytes and for the phospholipid classes and molecular species of frontal cortex samples obtained from serial biopsies and at the time of autopsy. From these analyses, the half-lives ofDHA and EPA in the phospholipids of plasma, erythrocytes, and cerebral cortex were estimated. The deficient brain rapidly regained a normal or even supernormal content ofDHA with a reciprocal decline in n-6 fatty acids, demonstrating that the fatty acids of the gray matter of the brain turn over with relative rapidity under the circumstances of these experiments. 

Herbal remedies that have been reported to be he-patotoxic include chaparral (Larrea tridentata), germander (Teucrium chamaedrys), and life root (Senecio aureus) [18]. Cases reported patients developing jaundice, fatigue, pruritus, markedly elevated serum liver enzyme levels, severe cholestasis, hepatitis, and hepatocellular injury or necrosis documented by serial liver biopsies [19-21]. Signs and symptoms may occur as early as 3 weeks to as late as 7 months following ingestion [20,21]. 

Patients with healed GERD were treated for up to 40 months with rabeprazole and monitored with serial gastric biopsies. Approximately 4% of patients had intestinal metaplasia at some point during follow-up, but no consistent changes were seen. Hepatic effects In patients with various degrees/types of hepatic disease, the AUC was prolonged (lansoprazole, esomeprazole, rabeprazole, pantoprazole), half-life was prolonged (lansoprazole, omeprazole, rabeprazole, pantoprazole), increased bioavailability was observed (omeprazole), decreased clearance with rabeprazole and increased maximum pantoprazole concentrations. 

Haemochomatosis should be treated with venesection, initially of 500 ml weekly and guided by serial serum ferritin levels and liver biopsy to assess residual iron stores. 

Whole-animal studies assess the percent of the applied dose absorbed into the body using classic techniques of bioavailability, where absorbed chemical is measured in the blood, urine, feces, and tissues with mass balance techniques. Recently, methods have been developed to assess absorption by measuring the amount of chemical in the stratum comeum because it is the driving force for diffusion. Cellophane tape strips are collected 30 minutes after chemical exposure and the amount of drug assayed in these tape strips correlates to the amount systemically absorbed. If the focus of the research is to determine the amount of chemical that has penetrated into skin, core biopsies may be collected and serially sectioned, and a profile of the chemical as a function of skin depth may be obtained. 

Snover, D.C., Sibley, R.K., Freese, D.K., Sharp, H.L., Bloomer, J.R., Najarian, J.S., Ascher, N.L. Orthotopic liver transplantation a pathological study of 63 serial hver biopsies from 17 patients with special reference to the diagnostic features and natural history of rejection. Hepatology 1984 4 1212-1222... 

Zachariae, H., Kragballe, K., Sogaard, H. Methotrexate induced cirrhosis studies including serial liver biopsies during continued treatment. Brit. J. Dermatol. 1980 102 407 —412... 

Gronbaek, K., Christensen, P.B., Hamilton-Dutoit, S., Federspiel, B.H., Hage, E., Jensen, O.J., Vyberg, M. Interobserver variation in interpretation of serial liver biopsies from patients with chronic hepatitis C. J. Viral Hepat. 2002 9 443-449... 

Reports of necrotizing leukoencephalopathy in association with methotrexate have been verified by biopsy or autopsy (25,26). Serial electroencephalography can predict this, since slow-wave activity develops during the administration of high-dose methotrexate. Autopsy has shown widespread necrosis and spongiosis in the cerebral and cerebellar white matter in such cases (25). 

In 22 of 29 patients (76%) who were treated with low-pulse doses of methotrexate for rheumatoid arthritis, liver biopsy specimens showed variability in liver cell nuclear size, glycogenated nuclei, and fatty change. Occasionally there was mild portal infiltration with lymphocytes. There were no significant differences in age, duration of treatment, or cumulative dose amongst the cases. Serial increases in serum transaminases and/or alkaline phosphatase activity and development of hypoalbuminemia during treatment were indicators of development of liver disease (54). 

Zachariae H, Kragballe K, Sogaard H. Methotrexate induced liver cirrhosis. Studies including serial hver biopsies during continued treatment. Br J Dermatol 1980 102(4) 407-12. 

Interstitial pneumonitis with severe respiratory failure has been reported in two patients (SEDA-21, 389) (SEDA-22, 418). One patient improved after mycophenolate mofetil was withdrawn, but interstitial fibrosis was found on serial lung biopsies. The other patient died from respiratory failure 3 months later. Although other drugs may have been involved in these two patients, one other reported case with recurrence of respiratory failure on each rechallenge of mycophenolate is particularly convincing. 

Sieberth HG, Clasen W, Fuhs M, IttelT, Kindler J, Mihatsch MJ. Serial kidney biopsies in patients with nephrotic syndrome treated with cyclosporin. J Autoimmun 1992 5 SuppI A 355-361. 

In addition to using sequential cycles to avoid the process of serial dilution, the principle of sequential cycles can be very useful when low amounts of RNA are present. We have quantitated MDR-1 mRNA from 40 cycles in extreme cases. In that situation, SW620 is diluted to 0.12 ng input RNA since amplification 40 cycles should give a PCR product equivalent to 125 ng input RNA amplified 30 cycles. Since greater variability results from this approach, the better solution is larger biopsy samples. 

Folate status may be reliably assessed by direct measurement of serum and erythrocyte or whole blood concentrations, and its metabolic function as coen2yme assessed by metabolite concentrations, such as plasma homocysteine (see Chapters 20 and 26). Serum folate concentrations are considered indicative of recent intake and not of tissue stores, but serial measurements have been used to confirm adequate intake. Whole blood or erythrocyte folate concentrations are more indicative of tissue stores and have been shown to have a moderate correlation with liver folate concentrations taken through a biopsy. Because folate is taken up only by the developing erythrocyte in the bone marrow and not by the mature cell, erythrocyte concentrations reflect folate status over the 120-day lifespan of the ceU. Urine folate excretion is not considered to be a sensitive indicator of folate status. ... 

The remodeling process, involving continuous resorption of both the mineralized portion of bone and the organic matrix, is coupled with the formation process and must precede it. In other words, in normal bone, formation cannot occur until resorption has taken place. In recent years much has been learned about this microscopic remodeling system which operates continuously in the entire skeleton.12 Bone cells known as osteoclasts are responsible for the resorption process. Formation and mineralization are initiated by cells known as osteoblasts. Modern histomorpho-metric techniques applied to the cells and surfaces of serial bone biopsies enable researchers to detect and quantitate malfunctions underlying the pathology in various types of metabolic bone disease. With this capability the utility of these techniques in diagnosis and evaluation of treatment are obvious. 

---