Pre-operative respiratory evaluation and management of patients for upper abdominal surgery.

Patients presenting for surgery, be it on an elective or emergency basis, do so in the hope that the anesthetic will be without risk. Yet complications which arise are not always due to anesthesia. More often, the surgical process and factors intrinsic to the patient are major determinants of outcome. Pre-operative assessment allows review of the patient and the proposed surgery, and formation of a plan of management for the pre-, intra-, and post-operative anesthetic care. This paper provides an overview of the pre-operative assessment and management of patients who are to undergo upper abdominal surgery, with the aim of minimizing their risk of post-operative pulmonary complications. In particular, factors which contribute to the development of post-operative respiratory problems are described.     

Glucocorticoid effects on zinc transport into colostrum and milk of lactating cows

Colostrum Zn concentrations were measured in eight randomly selected Holstein dairy cows. Overall mean Zn concentrations were highest within 12 h postpartum (257 +/- 14 microM, mean +/- SEM), fell to 141 +/- 8 microM by 24 h, and then declined at a linear rate of 30 microM/d during the following 48 h. Zn concentrations at 3 d (82 +/- 5 microM) were not different from 150-d milk samples (72 +/- microM). In a second experiment, 32 early-gestation cows were blocked by stage of lactation into four groups in a randomized block design and injected with 0, 15, 30, or 45 mg of dexamethasone. Milk and blood samples were collected at 0, 12, and 24 h after injection and analyzed for Zn, and for fat, protein, and lactose in milk. Cows administered 0 and 15 mg of dexamethasone showed no difference in milk Zn concentrations compared to pretreatment measurements; however, milk Zn concentrations in cows administered 30- and 45-mg doses increased significantly. Plasma cortisol decreased in the dexamethasone-treated cows. Plasma Zn and milk fat, protein, and lactose did not change. These data indicate that glucocorticoids can mediate Zn uptake and transport by the mammary glands of lactating cows and suggest that the high Zn concentration in colostrum could be a result of the preparturient surge of cortisol.     

Effects of nitrous oxide on mitochondrial and cell respiration and growth in Distichlis spicata suspension cultures

The reversible inhibition of respiratory activity could provide a novel approach to the preservation of traditionally hard to store plant germplasm such as clonal materials and recalcitrant seed. The gaseous anesthetic nitrous oxide caused a reversible, dose-dependent, partial inhibition of dioxygen utilization in mitochondrial particles isolated from cell suspension cultures of the salt-tolerant marsh grass Distichlis spicata, with maximal inhibition of 33% after 30 minutes exposure to an atmosphere of 80% nitrous oxide plus 20% oxygen. Respiration of whole cells required longer time to be affected by the anesthetic, and was reversibly inhibited an average of 19% when measured using a differential respirometer. Exposure to 80% nitrous oxide plus 20% oxygen for up to 10 days caused no measurable effect on cell growth.Abbreviations PCV packed cell volume - EDTA sodium ethylenediaminetetraacetic acid - BSA bovine serum albumin - MOPS 3(N-morpholino) propanesulfonic acid - TMPD N,N,N',N'-tetramethyl-p-phenylene diamine - STP standard temperature and pressure     

The identification and metabolism of GA9 and its metabolites in seed coats and shoots of pea,line G2

[³H]gibberellin A₉ was applied to shoots or seed parts of G2 pea to produce radiolabeled metabolites. These were used as markers during purification for the recovery of endogenous GA₉ and its naturally occurring metabolites. GA₉ and its metabolites were purified by HPLC, derivatized and examined by GC-MS. Endogenous GA₉, GA₂₀, GA₂₉ and GA₅₁ were identified in pea shoots and seed coats. GA₅₁-catabolite and GA₂₉-catabolite were also detected in seed coats. GA₇₀ was detected in seed coats following the application of 1 g of GA₉. Applied [³H]GA₉ was metabolized through both the 13-hydroxylation and 2-hydroxylation pathways. Labeled metabolites were tentatively identified on the basis of co-chromatography on HPLC with endogenous compounds identified by GC-MS. In shoots [³H]GA₅₁ and [³H]GA₅₁-catabolite were the predominant metabolites after 6 hrs, but by 24 hrs there was little of these metabolites remaining, while [³H]GA₂₉-catabolite and an unidentified metabolite predominated. In seed coats [³H]GA₅₁ was the initial product, later followed by [³H]GA₅₁-catabolite and an unidentified metabolite (different from that in shoots), with lesser amounts of [³H]GA₂₀, [³H]GA₂₉ and [³H]GA₂₉-catabolite. [³H]GA₇₀ was a very minor product in both cases. [³H]GA₉ was not metabolized by pea cotyledons.Edited by T.J. Gianfagna.Author for correspondence     

Fatal association between dieldrin-resistant and susceptible Australian sheep blowflies, Lucilia cuprina.

A novel phenomenon of interactions between genotypes of the dieldrin-resistance (Rdl) locus of the Australian sheep blowfly (Lucilia cuprina) is described. Susceptible adult flies exposed to dieldrin-resistant (Rdl/Rdl or Rdl/S) adults, raised from larvae grown on media containing sublethal concentrations of dieldrin, display mortality related to the concentration on which the resistant flies developed. The resistant flies excrete quantities of dieldrin that are toxic to susceptible flies. These observations provide an additional mechanism to those previously identified for the rapid evolution of resistance to dieldrin by L. cuprina.     

Vacuolar H(+)-translocating pyrophosphatases: a new category of ion translocase.

The membrane surrounding the central vacuole of plant cells contains an H(+)-translocating ATPase (H(+)-ATPase) and an H(+)-translocating inorganic pyrophosphatase (H(+)-PPase). Both enzymes are abundant and ubiquitous in plants but the H(+)-PPase is unusual in its exclusive use of inorganic pyrophosphate (PPi) as an energy source. The lack of sequence identity between the vacuolar H(+)-PPase and any other characterized ion pump implies a different evolutionary origin for this translocase. The existence of the vacuolar H(+)-PPase, in conjunction with increasing recognition of PPi as a key metabolite in plant systems, necessitates reconsideration of ATP as the primary energy source for membrane transport in plant cells.     

Adenine photodimerization in deoxyadenylate sequences: elucidation of the mechanism through structural studies of a major d(ApA) photoproduct.

The mechanism of the photodimerization of adjacent adenine bases on the same strand of DNA has been elucidated by determining the structure of one of the two major photoproducts that are formed by UV irradiation of the deoxydinucleoside monophosphate d(ApA). The photoproduct, denoted d(ApA)*, corresponds to a species of adenine photodimer first described by P?rschke (P?rschke, D. (1973) J.Am.Chem.Soc. 95, 8440-8446). From a detailed examination of its chemical and spectroscopic properties, including comparisons with the model compound N-cyano-N1-(1-methylimidazol-5-yl)formamidine, it is deduced that d(ApA)* contains a deoxyadenosine unit covalently linked through its C(8) position to C(4) of an imidazole N(1) deoxyribonucleoside moiety bearing an N-cyanoformamidino substituent at C(5). On treatment with acid, d(ApA)* is degraded with high specificity to 8-(5-amino-imidazol-4-yl)adenine whose identity has been confirmed by independent chemical synthesis. It is concluded that the primary event in adenine photodimerization entails photoaddition of the N(7)-C(8) double bond of the 5'-adenine across the C(6) and C(5) positions of the 3'-adenine. The azetidine species thus generated acts as a common precursor to both types of d(ApA) photoproduct which are formed from it by competing modes of azetidine ring fission.     

Acclimatory responses in enzymatic activity and metabolite concentrations in the tropical scorpion Heterometrus fulvipes

1. 1.|Changes in tissue metabolite concentrations and enzyme activities in the pedipalpal (PM) and heart (HM) muscles of the tropical scorpion Heterometrus fulvipes show that the metabolism in PM and HM is fundamentally reorganized following low (18°C) and high (38°C) temperature acclimation.

2. 2.|Changes in metabolite concentrations show that metabolite biosynthesis showed increases after cold acclimation but decreases after warm acclimation.

3. 3.|Similarly, changes in enzyme activities show a preponderance of glycolysis and HMP shunt activity after cold acclimation, while after warm acclimation glycogenolysis, oxidative metabolism and gluconeogenesis predominated.

4. 4.|Higher metabolite concentrations and enzyme activities both before and after thermal acclimation in HM reflect its greater compensatory abilities.

Evidence for the existence of cytoskeleton-bound polysomes in plants.

When conventional, high ionic strength buffers were used for the isolation of polysomes from pea plants, less than 20% were retained in the detergent-insoluble pellet. Reducing Tris, K+ and Mg++ to 10 mM increased retention to 70%, and when a new, microfilament-stabilizing buffer was used, retention increased to 80%. Conditions which favoured polysome pelleting at lower g forces permitted the retention of actin in the pellet. The data are consistent with the hypothesis that higher plants, like animals, contain cytoskeleton-(actin)-bound polysomes.