Biochemical effects of two promoters of hepatocarcinogenesis in rats

The effects of two promoters of hepatocarcinogenesis--phenobarbital and butylated hydroxytoluene (BHT)--on five hepatic biochemical parameters were examined in adult female rats. Phenobarbital given orally in two doses each of 110 mg/kg 21 and 4 hr before the rats were killed caused large increases in hepatic ornithine decarboxylase (ODC) activity and cytochrome P-450 content. Extending the number of phenobarbital treatments to five increased the hepatic enzyme induction and also caused a minor decrease in hepatic glutathione and a small increase in serum alanine aminotransferase activity. Two oral doses of 700 mg BHT/kg (20% of the LD50) caused hepatic DNA damage and induction of both ODC activity and cytochrome P-450 content. When the dose of BHT was reduced from 700 to 140 mg/kg no significant effects on the biochemical parameters were found. Both promoters of hepatocarcinogenesis were identified by their induction of ODC, a marker for promotional potential, but only BHT showed a potential for carcinogenic initiation. The biochemical parameters examined, particularly the alkaline elution technique for DNA damage, ornithine decarboxylase activity and serum alanine aminotransferase, may constitute a useful assay system for examining a compound's potential for carcinogenic initiation, carcinogenic promotion and cellular toxicity.     

Effect of chronic administration of different Bence Jones proteins on rat kidney

The role of Bence Jones proteins (BJPs) in the genesis of the renal dysfunction that develops in patients with multiple myeloma is not clearly defined. We previously evaluated renal function and morphology in a unique strain of rats (LOU/m) bearing tumors which synthesized BJPs with isoelectric points of 5.2, 4.3 and 6.7. Myeloma cast nephropathy developed in one tumor bearing group (pI 5.2), tubular necrosis was observed in another (pI 4.3), and renal function and histology remained normal in a third group (pI 6.7). To see if these renal outcomes were a function of the BJP being excreted or other factors which could be present in the tumor bearing animals, we have examined the effect of chronic intravenous administration of these three BJPs on renal function and histology in non-tumor-bearing LOU/m rats. Urine containing the BJP was collected from tumor bearing rats, sterilized by passage through a 0.2 mu millipore filter, concentrated to 50 mg/ml, and dialyzed extensively so as to remove material with a molecular weight less than 3500. Chronic indwelling-venous catheters were placed in non-tumor-bearing LOU/m rats and these rats were given 100 mg/day for five days of one of the three BJPs. Polyfructosan clearance (Cin) was measured prior to and following the five days of BJP administration. Renal histology was examined at the completion of the second Cin. In the pI 5.2 group (N = 6), a severe distal nephron cast nephropathy occurred and Cin fell from 2.88 +/- 0.24 to 0.90 +/- 0.17 ml/min (P less than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)     

The Busselton children's survey, 1983. Body size from five to 16 years of age

In 1983, 1623 primary and secondary schoolchildren took part in a health survey which was organized by the Busselton Population Studies Group. Age, sex, weight, height and country of birth were recorded for each child. Where possible, the country of birth of parents and the occupation of the father were extracted from previous Busselton surveys of adults. Compared with Perth schoolchildren, the difference in the attained weight and height of Busselton children at any age was small. This was so even though the two communities differ in location (rural compared with metropolitan), in ethnic origin (mainly British compared with diverse origins) and, probably, in social-rank distribution. Data from the two communities showed that a similar small secular increase in height had occurred since 1970/1971. This increase averaged at 1.2 cm for children at each year of age in Busselton and 1.5 cm to 1.6 cm for children in Perth.     

A new method for measuring continuity of care in family practice residencies

Continuity of relationship between physician and patient is a fundamental aspect of the health care provided by family physicians. Measurement of continuity has proved difficult, however. Commonly applied measures, usual provider of care (UPC), continuity of care (COC), and the modified continuity index (MCI), either ignore key aspects of continuity or provide misleading results. Consequently, a new measure of continuity, the modified, modified continuity index (MMCI), with a possible range of 0 to 1, was developed to overcome these problems. It was applied to a residency model practice, in which mean MMCI was found to be 0.59 (range 0.3 to 1.0). Mean COC was .41 and a mean MCI was .44. Thus, unlike COC and MCI, MMCI suggests fairly good continuity of care in this practice while still implying possible improvement. The MMCI should be useful for enhancing training and practice of family medicine.     

Spermidine synthase of Escherichia coli: localization of the speE gene.

We have obtained Escherichia coli mutants lacking spermidine synthase (putrescine aminopropyltransferase) and have found that the mutated gene (speE) is located immediately upstream from the gene coding for S-adenosylmethionine decarboxylase (speD); these genes are located at 2.7 minutes on the E. coli chromosome. Both genes are present in a 1795-base-pair fragment of E. coli DNA that was cloned into pBR322. Deletion of 105 bases upstream of speE caused a coordinate loss of both activities, indicating that speE and speD constitute a single operon. speE and speD have also been cloned separately in a high-expression vector; strains carrying these plasmids overproduce the respective enzymes.