Investigating the spatial and temporal variation of vape retailer provision in New Zealand: A cross-sectional and nationwide study.

Smoking rates have decreased in Aotearoa New Zealand in recent years however, vaping has shown a dramatic upward trend especially among young people; up to 10% of young New Zealanders are now regular vapers. Importantly, the long-term health consequences for their future life are largely unknown. The accessibility of vape retailers is important, particularly in relation to the youths' daily activities and places such as schools where they spend a considerable amount of time and socialise. Despite this, we know little about the spatial patterning of vape retailers and even less of their socio-spatial patterning around schools. This ecological study utilised data from the New Zealand Specialist Vape Retailers register on nationwide vape retailer locations and combined them with whole-population sociodemographic characteristics and primary and secondary school data. We identified the prevalence of vape retailers and their spatial distribution by area-level deprivation, ethnicity and urban-rural classification by using descriptive statistics and (spatial) statistical modelling on the area-, school- and individual students-level (using disaggregated data on students). We found that almost 97% of all vape retailers are located within 1,600m (∼20-min walk) and 29% within 400m (∼5-min walk) of schools. Our research also identified increasing inequities by deprivation and ethnicity both for the overall population and particularly for students in the most deprived areas who experience a disproportionate presence and increase of new vape store retailers that disadvantage schools and students in these areas. This difference was particularly prominent for Pasifika populations in major urban environments.

Triglyceride hydrolase activities and expression of fatty acid binding proteins in the human placenta in pregnancies complicated by intrauterine growth restriction and diabetes.

Triglyceride (TG) hydrolases in the placental microvillous plasma membrane (MVM) release fatty acids from circulating lipoproteins and represent the critical initial step in transplacental fatty acid transfer. We investigated the activity of two TG hydrolases in MVM isolated from placentas of appropriately grown for gestational age pregnancies and pregnancies complicated by intrauterine growth restriction (IUGR), insulin-dependent diabetes mellitus (IDDM) or gestational diabetes mellitus (GDM). In addition, we measured protein expression of lipoprotein lipase (LPL) in MVM and two fatty acid binding proteins (L- and C-FABP) in placental homogenates. The TG hydrolase activities were assessed by measuring hydrolysis of (3)H-trioleic acid incorporated into intralipid micelles after incubation with MVM. The placenta-specific TG hydrolase activity (optimum at pH 6) did not differ in the patient groups studied. MVM LPL activity (optimum at pH 8) was reduced by 47% in preterm IUGR (n = 8, P < 0.05), compared with gestational age-matched controls. The LPL activity in placentas of IDDM pregnancies was increased by 39% (n = 8, P < 0.05), compared with controls. No significant differences were observed in cases of GDM. We found no alteration in protein expression of LPL or C-FABP. The expression of L-FABP was increased by 112% (n = 8, P < 0.05) in IDDM and 64% (n = 8, P < 0.05) in GDM. These results indicate that alterations in MVM LPL activity and expression of L-FABP may contribute to the altered lipid deposition and metabolism in IUGR and diabetic pregnancies.

Activities of overt and latent diacylglycerol acyltransferases (DGATs I and II) in liver microsomes of ob/ob mice.

The effect of the ob/ob mutation on microsomal overt and latent acyl CoA:diacylglycerol acyl transferase activities (DGATs I and II) in liver microsomes of mice was investigated. Overt and latent hepatic DGAT activities for 16-week-old lean Ob/? mice were 0.42+/-0.14 and 1.57+/-0.04 micromol/mg/min, respectively. For ob/ob mice DGAT I and II activities were 1.17+/-0.28 and 3.09+/-0.78 micromol/mg/min, respectively. The hepatic triacylglycerol (TAG) concentration of 16-week-old mice was increased three-fold in ob/ob mice relative to those in lean controls. The data suggest that the increased rate of hepatic TAG secretion and intracellular accumulation in ob/ob mice is accompanied by parallel increases in the activities of both DGATs.

Insulin stimulation of hepatic triacylglycerol secretion and the etiology of insulin resistance.

The recent observations that insulin can either stimulate or inhibit triacylglycerol secretion by the liver, depending on prior metabolic (possibly insulinemic) state, have rationalized the many apparently contradictory observations, obtained over the past three decades, on the effects of the hormone on this aspect of hepatic metabolism. Extrapolation to the situation in vivo suggests that frequent stimulation of insulin secretion may result in a chronic stimulation of VLDL secretion, and increased delivery of acyl moieties to muscle, where they induce insulin resistance if provided in excess of the oxidative needs (mostly due to exercise) of the tissue. High fructose/sucrose diets, which also stimulate hepatic VLDL secretion, will have the same effect, especially if consumed frequently during the diurnal cycle. Due to the quantitative importance of muscle as a site for insulin-sensitive glucose metabolism, these effects may initiate the metabolic vicious cycle that results in the development of the metabolic syndrome, well in advance of overt obesity or the diagnosis of type-2 diabetes.

Further characterization of a novel triacylglycerol hydrolase activity (pH 6.0 optimum) from microvillous membranes from human term placenta.

We recently identified the presence of two distinct triacylglycerol hydrolases with pH optima of 6.0 and 8.0 in human placental microvillous membranes (MVM). The TAG hydrolase with a pH optimum of 8.0 has properties similar to lipoprotein lipase, whereas TAG hydrolase with a pH optimum of 6.0 still to be fully characterized. In order to understand the functional and structural relationships between these two TAG hydrolases of MVM we have further investigated their biochemical and molecular properties. The presence of oleic acid inhibited TAG hydrolase activity with a pH optimum of 8.0 by 60 per cent whilst it had very little effect on the pH 6.0 TAG hydrolase activity. K(m)values for TAG hydrolases at pH 6.0 and pH 8. 0 optima were 170.6 and 9.83 nmol triolein, respectively, whereas the corresponding V(max)values were 0.32 and 0.037 nmol oleic acid/min mg/protein. Treatment of MVM with phenylmethylsulphonofluoride or protamine had no effect on TAG hydrolase at pH 6.0 whereas both decreased activity at pH 8.0, by 70 per cent and 52 per cent, respectively (P< 0.05), compared with control. p-Chloromercuribenzoate inhibited both TAG hydrolase activities by 25-30 per cent whereas iodoacetate inhibited TAG hydrolase activity with optimum pH 8.0 by 74 per cent and the activity at pH 6.0 by 28 per cent. Unlike the TAG hydrolase activity at pH 8.0, the activity at pH 6.0 was not affected by heparin. TAG hydrolase activity at pH 6.0 was significantly decreased compared with that of pH 8.0 optimum TAG hydrolase activity in smokers placenta. A threefold increase in pH 6.0 TAG hydrolase activity was observed following differentiation, whereas membrane associated TAG hydrolase activity with optimum pH 8.0 did not change. The TAG hydrolase with optimum pH 6.0 was subsequently purified from MVM to almost 1000-fold enrichment of the activity over the starting material. The final preparation however, still contained three distinct protein bands (90, 70 and 45 kDa). When extracted from non-denaturing polyacrylamide gels, the 70 kDa protein was the only protein to have TAG hydrolysing activity and had a pH optimum of 6.0. Labelling of samples with [(14)C]tetrahydrolipstatin also confirmed that the TAG hydrolase active protein was a 70 kDa protein. In conclusion, we report that there is a 70 kDa TAG hydrolase with optimum pH 6.0 in human placental MVM which is quite distinct from placental lipoprotein lipase.

Characterisation of triacylglycerol hydrolase activities in human placenta.

Triacylglycerol hydrolase activities were characterised in homogenates, cytosol, and microvillous membranes (MVM) of human placenta. Homogenates of placenta exhibited three distinct triacylyglycerol hydrolase activities with pH optima 4.5, 6.0 and 8. 0. On further fractionation, placental cytosol exhibited both acid cholesterol ester hydrolase (pH 4.5) and hormone sensitive lipase (pH 6.0) activities, whereas purified placental MVM exhibited two distinct triacylyglycerol hydrolase activities; a minor activity at pH 8.0 and a second major activity at pH 6.0. Triacylglycerol hydrolase activity at pH 8.0 of MVM appeared to be lipoprotein lipase (consistent with criteria such as serum stimulation and salt inhibition), whereas at pH 6.0 the activity was unique in that it was almost abolished by serum, but was not affected by high NaCl concentrations. Our data, for the first time, demonstrate that human placental MVM, in addition to lipoprotein lipase, contain a newly identified triacylglycerol hydrolase activity at pH 6.0.