Background/Aim: Despite evidence linking type of obesity with subsequent organ malfunction, such a link with renal malfunction has not been widely researched. The aim of this study was to investigate percentage of total body fat (%TBF), and body fat distribution in relation to the renal function in overweight/obese subjects. Methods: Body mass index (BMI), waist-to-hip ratio (WHR), TBF (by bioelectric impedance), and albumin excretion rate (AER) were determined in 77 subjects: 48 overweight/obese (BMI ≧27.8 for men and ≧27.3 for women) and 29 controls (BMI <27.8 for men and <27.3 for women). Obese subjects were subdivided into those (n = 33) with central fat distribution (WHR ≧0.81 for women and ≧0.92 for men) and those (n = 15) with peripheral fat distribution (WHR <0.81 for women and <0.92 for men). Results: Obesity, irrespective of type, was significantly related to increased AER. Furthermore, in subjects who did not differ in %TBF, the age-adjusted relative risk of abnormal AER was 18 times greater in centrally obese subjects as compared with controls, while only four times greater in peripherally obese subjects. Conclusion: A significant difference in risk of renal malfunction was observed in individuals having the same %TBF, but differing in the distribution of this fat, with a central fat pattern being the greater risk.

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Student approaches to learning vary from surface approaches to meaningful, deep learning practices. Differences in approach may be related to students' conceptions of the subject, perceptions of the learning environment, prior study experiences and performance on assessment. This study aims to explore entering students' conceptions of the unit they are about to study and how they intend to approach their studies. It involved a survey of 203 (of 250) first year students in a cross disciplinary unit in the Faculty of Health Sciences. They were asked to complete an open-ended response survey, including questions on what they thought they needed to do to learn biochemistry and what they thought the study of biochemistry was about. A phenomenographic methodology was used to identify categories of description for the questions. The paper will describe the categories in detail, the structural relationship between the categories and the distribution of responses within categories. The study reports a relationship between conception of the topic and approaches to learning. Students with more complex and coherent conceptions of the topic report that they were more likely to adopt deeper approaches to study than those with more fragmented conceptions. However, compared to previous studies, a surprisingly high proportion of students with more cohesive conceptions still intended to adopt more surface approaches. This may reflect the particular context of their learning, namely in a compulsory unit involving material for which most students have minimal background and difficulty seeing its relevance. Implications for teaching such foundation material are discussed.

1. Transepithelial Na concentration difference, deltaCNa, across proximal tubules of rat kidney was measured at varying intraluminal Na concentrations (CNainfinity) under conditions of zero net volume and Na flux. Simultaneous stopped-flow intratubular and artificial peritubular capillary perfusion techniques were used together with intratubular raffinose to achieve zero net fluxes. Under these conditions in rat proximal tubules, deltaCNa represents active transport, JactNa, factored by permeability, PNa, plus an electrical factor depending on transepithelial potential difference. 2. The relationship between CNainfinity and deltaCNa appeared sigmoidal with saturation being reached when intratubular Na was above 80 m-mole/kg. In the presence of ouabain (10(-2)M) and scilliroside (10(-3)M) the relationship remained the same. The maximum deltaCNa was reduced by approximately 50% by cardiac glycoside inhibition whereas the half-saturation constant was essentially unchanged. These changes from the control represent simple non-competitive inhibition by the cardiac glycosides. 3. Absence of potential difference (p.d.) measurements precludes exact description of the relation between true active transport and substrate concentration but much evidence indicates that the apparently sigmoid relation in the presence and absence of cardiac glycoside inhibition, would be retained if correction of deltaCNa values were possible. Such results could then be explained if there are at least three or more sites for Na on the pump system, of which at least two are not cardiac glycoside sensitive. They would also unequivocally exclude the presence of a single-site single-pump system or the simple algebraic addition of two such units since the kinetic curves for both would be hyperbolic rather than sigmoidal.

To investigate the role of beta-adrenergic receptors in the genesis of pancreatic juice, we studied the effect of the agonist isoproterenol (25 or 2.5 mumol X 1(-1] on the isolated perfused rat pancreas and compared it with the effect of secretin (approximately 3 nmol X 1(-1). Isoproterenol stimulated flow of a HCO3-rich juice; the response was qualitatively similar to that evoked by secretin, but the flow rate was only about 70% of the maximum in vitro secretin response. We also studied the effects of the autonomic blockers propranolol, phentolamine, and atropine. None of the blockers altered basal pancreatic flow or the juice content of electrolytes or protein. The threshold for the response of the gland to isoproterenol was approximately 10 nmol X 1(-1), and effects appeared to be near maximal at approximately 1 mumol X 1(-1). As is the case with secretin stimulation in the rat, protein excretion was increased by isoproterenol in parallel with flow. However, juice potassium, which is increased by secretin, was not elevated. The effects of isoproterenol were antagonized by propranolol (25 mumol X 1(-1), and neither atropine nor atropine plus phentolamine had any effect on the gland response. We conclude that neither cholinergic nor adrenergic neurotransmitters are responsible for basal secretion. However, from the response of the gland to isoproterenol, it appears that stimulation of beta-adrenergic neural receptors is the counterpart to hormonal stimulation with secretin, just as activation of cholinergic receptors is to the actions of cholecystokinin.