Silver recovery and fixer management: a new approach

Existing methods of silver recovery need more attention than can be devoted to them by the staff of radiographic departments if they are to be operated at full efficiency. A study of the problems involved has led to the design of an electrolytic cell having a stainless steel anode and an expendable, carbon-fibre cathode. The fixing bath is recycled through the cell which maintains a low concentration of silver, thus cutting down the volume of replenisher required and the loss of silver to effluent, and improving the washing. The fixer can be run indefinitely without replacement, the tendency to discolour through the oxidation of developing agents being controlled partly by the use of the metal anode and partly by an absorptive resin. The operation of the system is controlled by a microprocessor that recognises the formats of the sheets of film being fed to the processor, maintains an inventory of the films used, and silver recovered, and adjusts the time of electrolysis as required. The microprocessor speaks to the operator, acknowledging the input of work, and will advise of any malfunction, or of the need to replace the cathode when fully loaded. The stored information is available to the holder of a key.

Distribution of adenosine metabolising enzymes between adipocyte and stromal-vascular cells of adipose tissue

Rat adipose tissue was digested with collagenase and separated into adipocytes and stromal-vascular cells. The adipocytes accounted for 40% of the total adipose tissue adenosine deaminase activity, 32% of 5'-nucleotidase activity and 87% of adenosine kinase activity. This distribution suggests that adipocyte are the major cell type involved in adenosine utilization in adipose tissue. Furthermore, it suggests that the high sensitivity of isolated adipocytes to adenosine is representative of their sensitivity of isolated adipocytes to adenosine is representative of their sensitivity in vivo.

Effects of prednisolone and dexamethasone in vivo and in vitro: studies of insulin binding, deoxyglucose uptake and glucose oxidation in rat adipocytes

We have studied the effects of dexamethasone and prednisolone in vitro and in vivo on insulin binding, deoxyglucose uptake and glucose oxidation in rat adipocytes. In the studies in vivo, rats were treated for 22 h with dexamethasone (30 micrograms/kg) or prednisolone (200 micrograms/kg). Following sacrifice, adipocytes were prepared and the results demonstrated that cells from prednisolone treated rats showed a 17% increase in insulin binding and increased rates of basal and insulin stimulated deoxyglucose uptake and glucose oxidation. Conversely, dexamethasone administration resulted in a 22% decrease in insulin binding, and decreased rates of deoxyglucose uptake and glucose oxidation by the cells. Thus, prednisolone and dexamethasone had opposite effects in vivo. In contrast to the opposite effects of the two glucocorticoids in vivo, dexamethasone and prednisolone (each at a concentration of 1 mumol/l) had similar effects on adipocytes in vitro. Incubation of adipocytes with the steroids did not alter insulin binding, while both agents led to a comparable decrease in the rates of basal and insulin stimulated deoxyglucose uptake and glucose oxidation. Thus, dexamethasone and prednisolone have opposite effects on adipocyte glucose metabolism in vivo but have similar effects in vitro.

HLA-D and -DR antigens in genetic analysis of insulin dependent diabetes mellitus

Three groups of patients with insulin-dependent diabetes mellitus, ascertained by different procedures, were investigated for HLA-A, B, C and D antigens (n = 164), and a subset (n = 93) for HLA-DR. Both HLA-D/DR3 and D/DR4 were strongly positively associated and D/DR2 was negatively associated with insulin-dependent diabetes. HLA-DR+ was found to be a better marker for insulin-dependent diabetes than Dw4. The HLA-B associations (B8, B15 and B18) were clearly secondary to the increases of HLA-D/DR3 and D/DR 4. The HLA associations did not differ between familial and isolated cases indicating that these two groups may well have a common genetic background. Based on analysis of HLA-haplotype sharing in affected sibling pairs, a simple dominant model of inheritance could be ruled out, and a simple recessive model was found unlikely. The relative risks for the HLA-Dw3,4 and HLA-DR3,4 phenotype were 21.2 and 44.4 respectively and exceeded those of both the HLA-Dw3 and HLA-DR3 (5.6 and 4.3) as well as the HLA-Dw4 and DR4 (10.1 and 10.5) phenotypes. This argues against an intermediate genetic model but further studies are needed to clarify whether there is more than one susceptibility gene for insulin-dependent diabetes mellitus within the HLA-system.

Relationship between negative cooperativity and insulin action

We have compared the respective abilities of porcine insulin and [LeuB25]insulin to enhance the rate of dissociation of receptor-bound [125I]insulin from IM-9 lymphocytes and isolated rat adipocytes and to increase the rate of adipocyte glucose transport and oxidation. Although porcine insulin (100 ng/mL) greatly enhanced the dissociation rate of previously bound [125I]insulin, [LeuB25]insulin (at a concentration yielding equivalent receptor occupancy) had no effect. Nevertheless, the analogue fully stimulated adipocyte glucose transport and oxidation at concentrations consistent with its reduced (1.7% of normal) intrinsic binding affinity. Activation of glucose transport by the analogue was rapid, and the corresponding rate of activation was indistinguishable from that produced by native insulin. The increased dissociation rate observed with increasing receptor occupancy by native porcine insulin has been interpreted as evidence for negative cooperative site-site interactions between occupied receptors. According to this formulation, [LeuB25]insulin is a "noncooperative" insulin analogue. Since this [LeuB25]insulin retains full biologic activity, the enhancement of the insulin dissociation rate at high levels of receptor occupancy does not reflect a phenomenon inherent in insulin's action to augment glucose metabolism.

The prevalence of psoriasis in Denmark

A representative random sample comprising approximately 4000 Danes, 16-99 years old, were questioned as to present or previous psoriasis eruption by non-medical, professional interviewers. Based on the information obtained, the point prevalence for men was 4.2%, for women 3.3%. 88% of those who believed themselves to be suffering from psoriasis stated that they had been treated by doctors for psoriasis and 71% by dermatologists and/or dermatological departments. The difference found between men and women is not statistically significant. The actual prevalence has been adjusted according to an estimated overcalculation of some 25% based on the number of false-positive answers to questionnaires in a twin study. The prevalence for men is thus adjusted to 3.2% and for women to 2.5%. The number of adult psoriatics in Denmark is estimated at approximately 113,000, of whom 71,000 suffer from mild psoriasis and 42,000 from more severe psoriasis.

Epidemiological studies of diabetes mellitus in Denmark. II. A prevalence study based on insulin prescriptions

The study aimed at tracing the population of insulin-treated diabetics living in the Funen County, Denmark (approximately 450000 inhabitants) on 1 July 1973. It was based on a recording of insulin prescriptions among all prescriptions handled by the pharmacies in Funen County during a five-month period. Through information from medical records and public registries the verification of the diagnosis and the identity of the insulin prescription holders were checked, and it is estimated that the completeness of the study material was above 98%. Age- and sex-specific prevalence rates of insulin-treated diabetes mellitus were calculated. The overall prevalence rate for males was 3.6 per 1,000 and that for females 3.3 per 1,000.

Hypermethioninaemia and 3-hydroxyisobutyric aciduria in an apparently healthy baby

An apparently healthy baby with persistent hypermethioninaemia excretes increased amounts of 3-hydroxyisobutyrate, 3-hydroxypropionate, beta-aminoisobutyrate and beta-alanine. A defect in the oxidation of methylmalonic and malonic semialdehydes is proposed but the cause of the hypermethioninaemia is obscure.