Orthotopic rat liver transplantation after long-term preservation by continuous perfusion with fluorocarbon emulsion.

Isolated rat livers have been stored for up to 25 hr using a continuous pulsatile perfusion technique with and without fluorocarbon emulsion oxygen carrier in the perfusate. After preservation, orthotopically isografted livers can maintain recipient animals in good health. The longest surviving animal is alive at 12 months. A prosthetic cuff technique for the portal vein anastomosis was specially developed for this experimental series. It has simplified vascular anastomosis after the portal vein cannulation that is required for machine preservation of the donor liver. We believe that the described method in the rat liver isograft model might be useful for studies of liver preservation.

Clinical biochemistry service for liver transplantation.

The first significant successes with human liver transplantation took place only in 1968, but the future for this new surgical procedure now seems assured. Its success is heavily dependent upon the provision of pathology services, in particular from clinical biochemistry. The experiences with some of the 39 British liver transplants carried out so far are recorded. At operation, a minimum of 20 technician-hours, usually outside normal working hours, is called for. In the immediate post-operative period, intensive biochemical monitoring is essential. Once the major homeostatic mechanisms are re-established after surgery, the principal biochemical investigations are those of organ function. While no specific test for rejection is yet available, the diagnosis of rejection can be made from results of the routine pathology investigations. The role of the clinical biochemistry laboratory in the management of these patients is to provide reliable results seven days a week on a range of tests. The clinical biochemist is also well placed to contribute to the solution of some of the outstanding problems of organ transplantation.

Some observations and improvements on SMA 6-60 determinations of creatinine.

Modifications to an earlier SMA 6/60 method for creatinine determinations are reported. The suggested procedure is linear for concentrations up to 15 mg/100 ml, shows no zero drift, and has a satisfactory analytical precision. Effects have been determined upon the analysis for a number of non-creatinine constituents of biological fluids. Recommendations are made for the optimum determination of plasma and urine creatinine.

Serum hydroxybutyrate dehydrogenase (HBD) assays in the clinical laboratory.

Measurement of serum hydroxybutyrate dehydrogenase (HBD) activity for suspected myocardial infarction will nowadays usually be carried out with a commercially available test kit. Four such kits have been compared and evaluated: British Drug Houses HBDH set, Boehringer Corporation LDH-1-Iso-enzyme ;alpha-HBDH' kit, Calbiochem alpha-HBDH Statpack, and Eskalab alpha-HBDH reagent tablets. Of the 100 sera examined, 60 were from patients believed to have suffered a recent myocardial infarction, and 40 samples were from patients aged between 45 and 65 years who had no known hepatic, renal, or cardiac pathology, these being used to determine the normal range for each kit. Under standardized conditions the activity found differed from kit to kit; the clinical value of the various assay systems in terms of their ability to discriminate between normal and pathological sera is assessed; and finally the cost and the convenience of use of each kit procedure are discussed. Theoretical and experimental evidence is provided in support of an assay temperature of 30 degrees C, and a plea is made for international agreement on enzyme assay conditions.

Study of membrane permeability in haemodialysis.

The efficiency of haemodialysis has been determined when a Watson-Marlow (Kiil) dialyser was used repetitively without changing the membranes. Dialysis efficiency was assessed from the clearance of creatinine and of urea from the patient's blood. No significant deterioration in dialysis could be detected in six dialyses through the same membrane. Leaving the dialyser unit for up to eight hours before washing it out after the completion of each dialysis did not appear to have any effect on dialysis efficiency.It was concluded that repetitive haemodialysis through the same membranes is possible, but careful monitoring of the patient to assess suitability for such treatment, and subsequently at each dialysis, is essential.

Work study of a desk computer in the clinical laboratory.

Calculating results from laboratory data is a time-consuming part of laboratory work, particularly in chemical pathology, and is a frequent source of mistakes. It is much less popular with technical staff than the basic laboratory work. The reasons for purchasing a desk computer, and its use to perform the calculations in a number of investigations and to convert AutoAnalyzer data into concentration units, are discussed. The introduction of a desk computer improved morale, speeded up the work, and reduced both fatigue and mistakes.