Cross-sectional research of school principals‘ view on placement of school nurses in Slovenian schools

Izvleček Izhodišča: V šoli otroci preživijo velik del dneva, zato ima šola pomembno vlogo pri zdravju otrok in mladostnikov pa tudi pri sodelovanju z zdravstvenimi službami. Namen: Ugotoviti stališče ravnateljev o pomenu, smotrnosti in o možnosti umestitve šolske medicinske sestre v osnovne šole. Preiskovanci in metode: Podatki so zbrani s strukturiranim anketnim vprašalnikom. Vzorec zajema 55,6 % (n = 266) celotne populacije ravnateljev osnovnih šol. Uporabljena je deskriptivna statistika. Soodvisnost je analizirana z multiplo regresijsko in dimenzije odvisne spremenljivke s faktorsko analizo. Rezultati: Na osnovnih šolah najpogosteje ukrepajo zaradi akutnega bolezenskega stanja (PV = 3,48), psihosomatskih (PV = 3,42) in kroničnih bolezni (PV = 3,22) (lestvica 1-6). Ravnatelji prepoznavajo potrebo po nalogah šolske medicinske sestre iz promocije zdravja in zdravstvenih storitev, saj je 11 od 13 predlogov dobilo v povprečju oceno nad 4 (lestvica 1-5). Najprimernejšo umestitev šolske medicinske sestre vidijo deloma v zdravstvenem domu, deloma v šoli (60,2 %); najprimernejši delodajalec je zdravstveni dom (59,4 %). Mnenja se ne razlikujejo glede na velikost šole in vključitev v mrežo Zdravih šol. Ravnatelji s šol, v katerih je telesnih poškodb učencev več, izražajo značilno večjo potrebo po šolski medicinski sestri (b = 0,208, p < 0,014), kar velja tudi za ravnatelje z mnenjem, da je usposabljanje učiteljev za prepoznavanje in ukrepanje ob zdravstvenih težavah v odgovornosti zdravstvenega doma (b = 0,270, p < 0,000). Zaključki: Ravnatelji menijo, da se v šolah srečujejo z zdravstvenimi težavami učencev, a učitelji za ukrepanje nimajo dovolj znanja niti kompetenc. Pozitivno prepoznavajo umestitev šolske medicinske sestre v šolo.

The allosteric mechanism of bovine liver glutamate dehydrogenase. Evidence from circular-dichroism studies for a conformational change in the ternary complex enzyme-(oxidized nicotinamide-adenine dinucleotide)-glutarate

1. Computer averaging of multiple scans was used to refine the circular dichroism spectrum of bovine liver glutamate dehydrogenase, revealing well-defined structure in the aromatic region. 2. The circular dichroism of NAD+ bound to glutamate dehydrogenase is strongly negative at 260nm, probably owing to immobilization of the adenosine moiety. Loss of the characteristic adenine-nicotinamide interaction suggests that the coenzyme is bound in an unstacked conformation. 3. Glutarate and succinate, substrate analogues that are both inhibitors competitive with glutamate, do not significantly perturb the circular-dichroism spectrum of the enzyme in the absence of NAD+. 4. In the presence of NAD+, 150nM-succinate decreases the negative circular dichroism corresponding to bound coenzyme, but does not affect the protein circular dichroism. However, ISOmM-glutarate causes profound alternations of the circular-dichroism spectra of the bound NAD+ and of the enzyme, indicative of a protein conformational change. This direct evidence of conformational change specifically promoted by C5 dicarboxylates confirms the previous inference from protection studies. 5. The conformational change is discussed in relation to the allosteric mechanism of glutamate dehydrogenase.

Some properties of a microsomal oleate desaturase from leaves

1. When [1-14C]oleoyl-CoA was incubated with a pea-leaf homogenate oleate was both incorporated into microsomal 3-sn-phosphatidylcholine and released as the unesterified fatty acid. The proportion of oleate incorporated into this phospholipid was dependent on the relative amounts of thiol ester and microsomal preparation present in reactions. 2. At the concentrations of microsomal preparation and [14C]oleoyl-CoA used to study oleate desaturation the metabolism of the thiol ester was essentially complete after 5 min incubation, but the loss of label from 3-sn-phosphatidylcholine oleate and the concomitant increase in radioactivity in the linoleate of this phospholipid proceeded at approximately linear rates over a 60 min period. The kinetics of labelling of unesterified linoleate was consistent with the view that this labelled fatty acid was derived from 3-sn-phosphatidylcholine. 3. Oleate desaturation required oxygen and with unwashed microsomal fractions was stimulated either by NADPH or by the 105 000g supernatant. Washed microsomal preparations did not catalyse desaturation, but actively was restored by the addition of NADPH, 105 000G supernatant or Sephadex-treated supernatant. NADPH could be replaced by NADH or NADP+, but not by NAD+. 4. Microsomal fractions from mature and immature maize lamina and expanding spinach leaves also rapidly incorporated oleate from ([14C]oleoyl-CoA into 3-sn-phosphatidylcholine, but desaturation of 3-sn-phosphatidylcholine oleate was detected only with microsomal preparations from immature maize lamina. 5. It is proposed that leaf microsomal preparations posses an oleate desaturase for which 3-sn-phosphatidylcholine oleate is either the substrate or an immediate precursor of the substrate.

Oxidation of formate by peroxisomes and mitochondria from spinach leaves

1. Spinach (Spinacia oleracea L.) leaf extracts catalyse the oxidation of formate to CO2. 2. Two enzymic systems are responsible for this oxidation, the peroxidatic action of catalase (EC 1.11.1.6) and NAD-dependent formate dehydrogenase (EC 1.2.1.2). 3. Formate dehydrogenase is mainly, if not exclusively, located in the mitochondria. This enzyme has a pH optimum of 6–6.5 and a Km for formate of 1.7mm in the presence of 1 mm-NAD+. 4. Peroxidatic action of catalase is presumed to take place in peroxisomes, since these seem to be the subcellular site of catalase. Formate oxidation at pH5 by chloroplast and mitochondrial fractions is due to their ability to generate H2O2 and the presence of contaminating catalase. 5. During photorespiration, peroxidatic oxidation of formate by catalase can occur over a wide range of pH values, but the rate of this reaction is probably controlled by the concentration of formate present, to an extent dependent on the pH.

Studies on the mechanism and regulation of C-4 demethylation in cholesterol biosynthesis. The role of adenosine 3′:5′-cyclic monophosphate

1. An assay for demethylation has been developed based on the release of tritium from 4,4-dimethyl[3α-3H]cholest-7-en-3β-ol (II). 2. The maximum release of 3H from 3α-3H-labelled compound (II) in a rat liver microsomal preparation occurs in the presence of NADPH and NAD+ under aerobic conditions. 3. Incubation of 3α-3H-labelled compound (II) with NADPH under aerobic conditions leads to the formation of a 3α-3H-labelled C-4 carboxylic acid. This compound undergoes dehydrogenation on subsequent anaerobic incubation with NAD+. 4. The 3H released from the steroid was located in [4-3H]nicotinamide and the medium. Incubation with synthetic [4-3H2]NADH gave a similar result. 5. In the presence of glutamate dehydrogenase and α-oxoglutarate part of the 3H released from the steroid was transferred to glutamate. 6. A series of 3-oxo steroids were reduced equally well by [4-3H2]NADH and [4-3H2]NADPH. The reduction of 5α-cholest-7-en-3-one was shown to use the 4B H atom from the nucleotide. 7. 3′:5′-Cyclic AMP was shown to be a competitive inhibitor of the 3β-hydroxy dehydrogenase enzyme in the demethylation reaction.

The roles of pregn-5-ene-3β,20α-diol and 20α-hydroxy steroid dehydrogenase in the control of progesterone synthesis preceding parturition and lactogenesis in the rat

1. The activity of 20α-hydroxy steroid dehydrogenase in rat ovarian corpora lutea increased at least 50-fold between 2 days before and 2 days after parturition, and then fell gradually during lactation. The activity of 3β-hydroxy Δ5-steroid dehydrogenase decreased by 50% at parturition but remained constant at other times. 2. The 20α-hydroxypregn-4-en-3-one/progesterone concentration ratio in the ovary fell tenfold between 1 day before and 1 day after parturition, in contrast with the increase of the ratio for these steroids in plasma. 3. Pregnenolone was metabolized in intact cells or cell-free systems either to pregn-5-ene-3β,20α-diol and then to 20α-hydroxypregn-4-en-3-one by 20α-hydroxy steroid dehydrogenase and 3β-hydroxy Δ5-steroid dehydrogenase respectively, or directly to progesterone by the latter enzyme. The relative activities of these pathways appeared to reflect the relative amounts of the two enzymes and the concentrations of their respective coenzymes NADPH and NAD+. 4. From these and other observations it was concluded that the cessation of progesterone secretion, which precedes parturition and lactogenesis at the end of pregnancy, is partly due to the redirected metabolism of pregnenolone away from progesterone and towards 20α-hydroxypregn-4-en-3-one as the secreted end product. This is primarily the consequence of the sharp increase in the activity of 20α-hydroxy steroid dehydrogenase. This mechanism is super-imposed on the already declining rate of net Δ4-steroid release by the ovary. 5. A relationship of these pathways to subcellular compartments of luteal cells is proposed.

The control of isocitrate oxidation by rat liver mitochondria

1. The factors capable of affecting the rate of isocitrate oxidation in intact mitochondria include the rate of isocitrate penetration, the activity of the NAD-specific and NADP-specific isocitrate dehydrogenases, the activity of the transhydrogenase acting from NADPH to NAD+, the rate of NADPH oxidation by the reductive synthesis of glutamate and the activity of the respiratory chain. A quantitative assessment of these factors was made in intact mitochondria. 2. The kinetic properties of the NAD-specific and NADP-specific isocitrate dehydrogenases extracted from rat liver mitochondria were examined. 3. The rate of isocitrate oxidation through the respiratory chain in mitochondria with coupled phosphorylation is approximately equal to the maximal of the NAD-specific isocitrate dehydrogenase but at least ten times as great as the transhydrogenase activity from NADPH to NAD+. 4. It is concluded that the energy-dependent inhibition of isocitrate oxidation by palmitoylcarnitine oxidation is due to an inhibition of the NAD-specific isocitrate dehydrogenase. 5. Kinetic studies of NAD-specific isocitrate dehydrogenase demonstrated that its activity could be inhibited by one or more of the following: an increased reduction of mitochondrial NAD, an increased phosphorylation of mitochondrial adenine nucleotides or a fall in the mitochondrial isocitrate concentration. 6. Uncoupling agents stimulate isocitrate oxidation by an extent equal to the associated stimulation of transhydrogenation from NADPH to NAD+. 7. A technique is described for continuously measuring with a carbon dioxide electrode the synthesis of glutamate from isocitrate and ammonia.