INTERACTION BETWEEN EPIDERMAL GROWTH FACTOR AND ARGININE VASOPRESSIN IN RENAL MEDULLARY MEMBRANES

1. Epidermal growth factor is a potent mitogen that causes natriuresis, diuresis and inhibition of arginine vasopressin-induced water reabsorption. 2. The aim of this study was to determine any interaction between epidermal growth factor and the V1 (vascular) and/or V2 (antidiuretic) arginine vasopressin receptor subtypes. 3. Radioligand binding displacement assays demonstrated that although arginine vasopressin related peptides displaced both radioligands from renal medullary membranes at low concentrations epidermal growth factor displaced neither. 4. Arginine vasopressin V2 receptor second messenger cyclic adenosine monophosphate (CAMP) production was inhibited by epidermal growth factor (IC₅₀ 2 ± 10^?7 mol/L) as was sodium fluoride cAMP production but only at much higher concentrations. 5. Therefore the diuretic effect of epidermal growth factor is not via direct antagonism of arginine vasopressin receptors but seems mediated via inhibition of the V2 second messenger system.     

Resilience in Families with Children and Adult Members with Intellectual Disabilities: Tracing Elements of A Psycho‐Social Model

Aim This paper seeks to illumine how families with children and adult members with intellectual disabilities manage to manifest a buoyant and durable capacity over time. It is therefore concerned centrally with the idea of resilience. Method Drawing from diverse theoretical literatures from child development and protection and gerontology, the paper begins with a review of constructions of resilience. In an attempt to assess where there seems to be support for resilience in families, the core of the paper tests empirical evidence about positive experiences of families supporting children and adults with intellectual disabilities against the theoretical literature on resilience. Result and Conclusions The findings are used to suggest conditions under which resilience is produced and maintained, and to identify emergent elements of a psycho‐social model of resilience in families with children and adult members with intellectual disabilities.     

Prostate cancer: Prevalence and treatment in African men

Epidemiological data from the United States of America (USA) indicate that the incidence and mortality of prostate cancer is higher among Black African-American men (AAM) than among White (Caucasian) American men (CAM). Earlier studies suggesting that prostate cancer is relatively rare among indigenous Black men in Africa are probably flawed by underreporting because recent studies indicate that the incidence rates among Black men are similar to those of White men living in Africa. The higher incidence of prostate cancer among AAM has been ascribed to racial differences in genetic susceptibility, dietary factors, or androgen metabolism. However, it may also be due to registration artefacts because in Africa the reported incidence rates of prostate cancer in different countries correlate directly with the per capita gross national product, suggesting improved access to medical facilities is responsible for higher reported incidence rates.

The greater prostate cancer mortality among AAM may result from higher tumour grade and stage and higher serum PSA at presentation, but it has also been suggested that prostate cancer is biologically more aggressive in AAM than in CAM. However, recent studies indicate that tumour grade and stage and serum PSA at presentation are similar in the races, with no difference in survival after multivariate analysis controlling for pretreatment cancer severity. This suggests that the higher prostate cancer mortality among AAM results from socio-economic factors and limited access to healthcare. Black men living inside as well as outside of Africa still tend to present with locally advanced or metastatic prostate cancer due to lack of early detection programmes.     

Late-onset and Recurrent Neonatal Group B Streptococcal Disease Associated with Breast-milk Transmission

The purpose of the study was to determine the epidemiological relationships in three unrelated cases of neonatal late-onset Group B streptococcal (GBS) disease and maternal breast-milk infection with GBS. All deliveries were by cesarean section; case 1 was at term, and cases 2 and 3 were at 32- and 33-wk gestation, respectively. Case 1 relates to a mother with clinical mastitis and recurrent GBS infection in a 20-day-old male infant. Following antibiotic therapy and cessation of breast-feeding, the infant recovered without sequelae. Case 2 refers to a mother with clinical mastitis and the occurrence of late-onset GBS disease in 5-wk-old male twins. Despite intervention, one infant died and the second became ill. Following antibiotic therapy and cessation of breast-feeding, the surviving infant recovered without sequelae. Case 3 refers to a mother with sub-clinical mastitis and late-onset GBS infection occurring in a 6-day-old female twin. Following intervention, the infant recovered but suffered a bilateral thalamic infarction resulting in developmental delay and a severe seizure disorder. Following recovery of GBS from an inapparent mastitis and cessation of breast-feeding, the second infant remained well. Blood cultures from all affected infants and maternal breast milk were positive for GBS. Epidemiological relationships between neonatal- and maternal-derived GBS isolates were confirmed by a random amplified polymorphic DNA polymerase chain reaction assay (RAPD-PCR). This study is significant in that it has demonstrated that maternal milk (in cases of either clinical or sub-clinical mastitis) can be a potential source of infection resulting in either late-onset or recurrent neonatal GBS disease.