Bilirubin measured on a blood gas analyser: a suitable alternative for near-patient assessment of neonatal jaundice?

The reliability of a recently released total bilirubin assay for a blood gas analyser was assessed in two Australian hospital laboratories. The instrument computes total bilirubin concentration from multi-wavelength absorbance measurements of undiluted whole blood or plasma. Performance of the Radiometer ABL 735 blood gas analyser bilirubin method (software version 3.6) was compared with a proven Roche diazo method for Hitachi analysers, calibrated using primary standards prepared from NIST SRM 916a bilirubin. Acceptable bilirubin results were found over a wide concentration range for most neonatal samples of whole blood or plasma. For adult specimens, bilirubin results were approximately 10% lower on the blood gas analyser. Within-run imprecision (whole blood) was < 2.5%, between-day imprecision (synthetic controls) < 1.0%, and the bilirubin assay for both whole blood and plasma was linear to 1,000 micromol/L. Using sampling options from 35 microL to 195 microL, bilirubin results differed by less than 3%, with a 95 microL syringe option producing the highest results. We conclude that the Radiometer ABL 735 bilirubin assay is suitable for near-patient assessment of neonatal jaundice using whole blood, thus eliminating the need for sample centrifugation. Verification using laboratory methods can be used when required. A positive correction of approximately 10% is required for adult specimens to conform with Hitachi results (SRM 916a calibration), possibly due to the optical characteristics of the higher proportion of conjugated bilirubin and other substances present in most adult samples.

Avian polyomavirus infection and disease in a green aracaris (Pteroglossus viridis).

Avian polyomavirus (APV) is one of the most significant pathogens of domestically raised psittacine birds (parrots). One or more APVs are suspected to infect nonpsittacine cage birds, but the relationship of these viruses to the APV infecting parrots remains unclear. In this report, for the first time, we fully document an APV infection in a nonpsittacine cage bird, a green aracaris (Pteroglossus viridis). Grossly, this bird evidenced generalized hemorrhage. Histologically, there was severe hepatic necrosis, splenic necrosis, and the presence of lightly basophilic to clear pannuclear inclusion bodies and karyomegaly in splenocytes and renal mesangeal cells, all characteristic lesions of APV infection in parrots. APV DNA was amplified directly from the liver by polymerase chain reaction and sequenced. The virus differed from the original APV sequence by only 24 base pairs (0.48% of the genome), demonstrating that it is a variant of the APV. A serologic survey of the remaining birds in the aviary demonstrated anti-APV antibody in two cockatoos, two cockatiels, a laughing kookaburra, a Lady Ross turaco, and five zebra finches. The remaining green aracaris was seronegative. The sequence and serologic data suggest that the APV that infected the green aracaris originated in a parrot and was capable of infecting birds from at least four orders.

Aluminium absorption and antacid therapy in infancy.

The aim of this study was to determine whether infants absorb aluminium from antacid therapy. The study was conducted at Torrens House, a service provided by Child and Adolescent Health Services (CAFHS) for feeding and settling problems. Over an 11 week period, all patients receiving antacid therapy were studied. Patients not receiving antacids but of similar age acted as controls. Plasma and urine levels of aluminium were measured. The 15 infants receiving antacids had higher aluminium levels than the 17 controls (plasma 3.3 +/- 2.2 mumol/L vs 1.5 +/- 1.5 mumol/L, P less than 0.01; urine 25.1 +/- 27.6 mumol/L vs 1.1 +/- 1.8 mumol/L, P less than 0.004). The response was variable with 50% of infants receiving antacids recording plasma aluminium levels previously associated with toxicity in patients with renal failure after chronic exposure to aluminium. We conclude that infants absorb aluminium from antacids and suggest that patients receiving have their plasma levels monitored to identify those at possible risk of toxicity.

Fine-needle aspiration biopsy for the measurement of hepatic iron concentration.

The potential application of fine-needle aspiration liver biopsy in the documentation of hepatic iron overload has been assessed in iron-loaded rats. Fine-needle aspiration and standard liver biopsy specimens were obtained from three groups of animals supplemented with oral and parenteral iron for 2 to 6 mo. The mean dry weights of standard and fine-needle biopsy specimens were 7.41 +/- 0.77 (+/- S.E.M.) and 0.57 +/- 0.54 mg, respectively. Hepatic iron in fine-needle aspiration biopsy specimens correlated significantly with hepatic iron in standard liver biopsy specimens as measured by biochemical determination, computerized image analysis and histological grading (r greater than 0.9, p less than 0.001). In conclusion, we have shown that fine-needle aspiration biopsy of the liver can obtain sufficient tissue for biochemical measurement of the hepatic iron concentration in an animal model of iron overload. The clinical applications of fine-needle aspiration liver biopsy in human beings with iron overload is currently being investigated.

Psittacine vaccines.

Vaccines for Pachecho's disease and Psittacine pox are described. Clinical trials of these vaccines are discussed, and vaccination recommendations are included.

Avian practice tips.

This article reviews the therapy of the sick bird. Common differential diagnoses, inpatient versus outpatient therapy, preventive medicine, and post-purchase examinations are discussed. The importance of client education is stressed.

ELISA testing for avian chlamydiosis.

Studies of Chlamydia antigen ELISA and BELISA assays are reviewed. This article includes descriptions of university studies and clinical laboratory usage of assays. A guide to clinical interpretation of tests is included.

Aluminium absorption in infancy.

The use of aluminium-containing medications and aluminium contamination of infant formulae is common. We aimed to determine whether aluminium absorption occurs after antacid ingestion. Plasma and urinary levels of aluminium were measured before and after antacid therapy in seven infants whose mean gestational age was 36 +/- 2 weeks and postnatal age 11 +/- 5 days. Antacid therapy (400-800 mumol aluminium) was given with feeds for 2 days. Plasma aluminium levels increased and reached toxic levels (0.64 +/- 0.33 mumol/L vs 3.48 +/- 2.86 mumol/L, P = 0.029). Urinary aluminium: creatinine ratio also increased. These results demonstrate that infants absorb aluminium from antacids and raise the concern of aluminium toxicity.

Delivery of vitamin A from parenteral nutrition solutions in neonates.

The delivery of Vitamin A from parenteral nutrition may be suboptimal. To investigate this sample solutions were prepared and Vitamins A and E concentrations from the solution bags and the efflux from the lines were measured over a 24 h period. The results show that mean Vitamin A levels in the solution bags declined from a range of 57-66% to 17% of expected over 24 h and at the efflux of the lines from a range of 13-29% to 4% of expected, giving a calculated delivery of 10% of expected. There is no improvement with light protection or an ethylene vinyl acetate system. Mixing the vitamin preparation in lipid showed less decline (from 92 to 70% of expected over 24 h), but the delivery was variable. When vitamins were added to a lipid-dextrose-amino acid solution, there was minimal loss from the solution bag and line with a calculated delivery of 94% of expected. The delivery of Vitamin E from all systems was constant with a mean calculated delivery of 74% of expected. It was concluded that the mixing of multivitamins in dextrose-amino acid-electrolyte solutions results in poor delivery of Vitamin A and this is improved by mixing lipid solution. This is important in preterm infants who are prone to become Vitamin A deficient.

Aluminum concentrations in infant formulae.

The aluminum concentrations in breast milk and in 25 commercially available infant formulae were measured. The mean concentration in breast milk was 49 micrograms/L while concentrations in most of the humanized formulae were less than 500 micrograms/L. Higher concentrations were found in Nan, Prem Enfamil and the three soya formulae. We suggest that all formulae have the potential to be contaminated with aluminium, and to varying degrees in different batches. Until it is known whether aluminium toxicity occurs in normal infants fed these formulae, it seems reasonable to expect manufacturers to routinely measure aluminium and keep aluminium contamination to a minimum. This may be especially important for formula fed to infants with compromised gastrointestinal and renal systems.

An enteric coronavirus infection of cats and its relationship to feline infectious peritonitis.

An enteric coronavirus that is antigenically closely related to feline infectious peritonitis virus (FIPV) is ubiquitous in the cat population. This virus has been designated feline enteric coronavirus to differentiate it from FIPV. The virus is shed in the feces by many seropositive cats; in catteries it is a cause of inapparent to mildly severe enteritis in kittens 6 to 12 weeks of age. The virus may produce a more severe enteritis in young specific-pathogen-free kittens. Feline enteric coronavirus selectively infects the apical columnar epithelium of the intestinal villi, from the caudal part of the duodenum to the cecum. In severe infections, there are sloughing of the tips of the villi and villous atrophy. Many cats recovering from the disease remain carriers of the virus. Recovered cats, observed for 3 to 24 months, remained healthy and did not develop peritonitis, pleuritis, or granulomatous disease. The relationship of feline enteric coronavirus and FIPV was studied. Although the viruses were antigenically similar, they were distinctly different in their pathogenicities. The enteric coronavirus did not cause feline infectious peritonitis in coronavirus antibody-negative cats inoculated orally or intraperitoneally nor in coronavirus antibody-positive cats inoculated intraperitoneally or intratracheally. Serologic tests, using FIPV, canine coronavirus, and transmissible gastroenteritis virus of swine as substrate antigens in fluorescent antibody procedures may not accurately identify FIPV infection. These tests do not appear to distinguish between FIPV and this feline enteric coronavirus.

Comparison of three kits for the enzymatic determination of urea.

A comparative evaluation of Beckman (A), Boehringer (B), and Calbiochem (C) kits for the enzymatic end-point determination of urea has been carried out. Acceptable within-day and day-to-day precision was obtained with all kits. The recoveries obtained fulfilled the criteria of Logan (CRC Critical Reviews in Clinical Laboratory Sciences, 1972, 3, 271-289). Correlation between the results obtained by all kit methods and the diacetyl monoxime continuous-flow method, the reference method in this study, was excellent, but all methods evidenced a net negative bias at urea levels up to at least 20 mmol/1. We recommend kit A as the most satisfactory for routine use, consider kit B to be in the main acceptable, and suggest that kit C has disadvantages regarding both the accuracy attainable with quality control materials and the lack of information on blank correction for interfering compounds.

Evaluation of a radiometric method for determination of total and unsaturated iron-binding capacities and serum iron.

We describe an evaluation of the "RES-OMAT FE-59" radiometric kit (Mallinckrodt Australia Pty. Ltd.) for determination of total iron-binding capacity and unsaturated iron-binding capacity; serum iron may be calculated from total iron-binding capacity and unsaturated iron-binding capacity. Values obtained on patients' sera were compared with those obtained by continuous-flow analysis; correlation coefficients were 0.92, 0.93, and 0.88 for total iron-binding capacity, unsaturated iron-binding capacity, and iron, respectively. Precision between-run and within-run was almost identical and compares very favorably with that reported by Dixon [Ann. Clin. Biochem. 10, 127 (1973)] and that achieved in inter-laboratory surveys. Analytical recovery averaged only 83.5%, but results of analyses of sera with assigned or consensus values showed good accuracy. Satisfactory performance cannot be achieved with lyophilzed bovine quality-control materials. The kit has significant technical advantages over colorimetric methods and good short- and long-term analytical performance.

Chemical analysis of ceramic materials, containing uranium and plutonium, arising from the development of nuclear fuels.

A comprehensive and critical review of analytical methods used in nuclear fuel technology.