Group HM Research Articles

Magnesium Sulfate Prevents Remifentanil-Induced Postoperative Hyperalgesia in Patients Undergoing Thyroidectomy

In a randomized, double-blind, prospective study, we investigated whether an intraoperative high versus low dose of remifentanil increased postoperative hyperalgesia and whether magnesium can prevent remifentanil-induced hyperalgesia. Ninety patients undergoing thyroidectomy were randomly assigned to 1 of 3 groups. Remifentanil was intraoperatively infused at 0.05 μg/kg/min (group LO) or 0.2 μg/kg/min (groups HI and HM). Patients in group HM received MgSO(4) 30 mg/kg at induction followed by an intraoperative infusion of 10 mg/kg/h. Mechanical pain thresholds on the forearm and periincisional area were assessed by von Frey filament the evening before surgery and postoperatively at 24 and 48 hours. Pain measured on a verbal numerical rating scale (VNRS) (0-10) and additional analgesics were recorded in the postanesthesia care unit postoperatively at 6, 24, and 48 hours. There was a significantly greater decrease in pain threshold on the periincisional area at 24 and 48 hours postoperatively in group HI, as compared with the other 2 groups. The 95% confidence intervals for the mean difference in pain thresholds on the periincisional area at 24 and 48 hours postoperatively were 0.31 to 1.11 and 0.36 to 1.14 for group HI versus group LO, 0.45 to 1.26 and 0.54 to 1.32 for group HI versus group HM (values are log(10) of force in milligrams). The change in pain threshold on the forearm was similar among the groups. Group HI had significantly higher VNRS scores (median [interquartile range], 3 [2-4]) than group LO (2 [1-3] and group HM (2 [1-3]) at 48 hours postoperatively. The 95% confidence intervals for median difference in VNRS score at 48 hours postoperatively were 1 to 2 for group HI versus group LO and 0 to 2 for group HI versus group HM. There were no significant differences in the number of patients who requested rescue analgesics in the postoperative anesthesia care unit and general ward during 48 hours postoperatively among the 3 groups. A relatively high dose of intraoperative remifentanil enhances periincisional hyperalgesia. Intraoperative MgSO(4) prevents remifentanil-induced hyperalgesia. However, hyperalgesia did not reach clinical relevance in terms of postoperative pain or analgesic consumption in patients undergoing thyroidectomy.

Effects of hydrogen-rich saline combined with mild hypothermia on cerebral ischemia-reperfusion injury in rats

Objective To investigate the effect of hydrogen-rich saline combined with mild hypothermia on cerebral ischemia-reperfusion (IR) injury in rats. Methods Fifty male SD rats, aged 9-10 weeks, weiging 250-300 g, were randomly divided into 5 groups (n= 10 each): sham operation group (group S), group IR, hygrogen-rich saline group (group H), mild hypothermia group (group M) and hydrogen-rich saline + mild hypothermia group (group HM). In group IR, H, M and HM cerebral IR was induced by 15 min ligation of bilateral carotid artery followed by 6 h reperfusion. In group H and HM intraperitoneal hydrogen-rich saline 5 ml/kg was injected immediately after reperfusion, while the equal volume of normal saline was injected instead of hydrogen-rich saline in the other three groups. At the same time, the rectal temperature was maintained at 37-38 ℃ in group S,IR and M, while it was reduced to 32-34 ℃ by physical method within 15 min, lasting for 6 h, in group M and HM. The animals were sacrificed after 6 h of reperfusion, and then the hippocampus was removed for microscopic examination. The expression of HO-1 and content of MDA and TNF-α were determined by Western blot. Results The cerebral IR injury was attenuated in group H, M and HM compared with group IR, with the slightest injury in group HM. The expression of HO-1 and content of MDA and TNF-α were significantly higher in group IR, H, M and HM than in group S. The expression of HO-1 was significantly higher, while the content of MDA and TNF-α were lower in group H, M and HM than in group IR, and in group HM than in group H and M. There was no significant difference in the expression of HO-1 and content of MDA and TNF-α between group H and M. Conclusion Hydrogen-rich saline combined with mild hypothermia can attenuate cerebral I/R injury in rats via up-regulating the expression of HO-1 and decreasing the content of MDA and TNF-α in hippocampus. Key words: Hydrogen; Hypothermia, induced; Reperfusion injury; Brain

Description of outcomes of experimental infection with feline haemoplasmas: Copy numbers, haematology, Coombs’ testing and blood glucose concentrations

The aim of this study was to compare blood copy, haematological and glucose values between cats experimentally infected with either Mycoplasma haemofelis (Group HF: 10 cats), ‘Candidatus M. haemominutum’ (Group HM: 3 cats) or ‘Candidatus M. turicensis’ (Group TU: 3 cats). Blood samples were collected regularly up to 85 days post-infection (DPI) for haemoplasma real-time quantitative PCR, haematology, Coombs’ testing and blood glucose measurement. Statistical analysis was performed using a general linear model (ANOVA) appropriate for a repeated measures experiment with significance set as P<0.05. Cats in Group TU had significantly lower blood copy numbers than cats in Group HF (P<0.001) and HM (P<0.001). All Group HF cats developed anaemia (often severe), macrocytosis and evidence of erythrocyte-bound antibodies whereas Groups HM and TU cats did not. Group HF had significantly lower PCVs, haemoglobin concentrations and red blood cell counts, and significantly higher mean cell volumes, than Groups HM and TU. In Group HF, erythrocyte-bound antibodies reactive at 4°C (both IgM and IgG) appeared between 8 and 22 DPI and persisted for two to four weeks, whereas those reactive at 37°C (primarily IgG) appeared between 22 and 29 DPI and persisted for one to five weeks. In most cats antibodies appeared after the fall in haemoglobin started. Although Group TU had significantly lower glucose concentrations than Groups HF (P=0.006) and HM (P=0.027), mean blood glucose concentrations remained within the reference range in all groups. This study demonstrates that M. haemofelis infection, in contrast to ‘Candidatus M. haemominutum’ and ‘Candidatus M. turicensis’ infection, can result in a severe macrocytic anaemia and the development of cold and warm reactive erythrocyte-bound antibodies.

Interactions between nutritional and opioidergic pathways in the control of LH secretion in male sheep

Our aim was to determine the role of opioidergic processes in the effects of nutrition on the secretion of LH pulses in the mature male sheep. In the first of three experiments, adult Merino rams were acclimatised to a maintenance diet and then allocated to one of three dietary groups ( n = 5): continuation of the maintenance diet (Group M); reduction to half of the maintenance allocation (Group HM); or supplementation of the maintenance diet with lupin grain (Group HD). An initial administration of naloxone (2 mg/kg body weight, i.v.) was followed at 40-min intervals by three further administrations (1 mg/kg). Blood was sampled every 20 min for 12 h before the initial naloxone administration and then for a further 6 h. LH pulse frequency after naloxone treatment was significantly higher in Group HD than in Group HM ( P < 0.05). The second study tested whether the response to naloxone depended on calcium status. We used 22 adult Merino rams in two consecutive experiments, one in which the rams were fed a maintenance diet, and one in which the rams were fed with the maintenance diet plus 1 kg lupin grain for 5 weeks. In both experiments, rams were allocated to groups that received one of the following treatments: (a) 0.02 g/kg calcium borogluconate + 0.2 mg/kg naloxone hydrochloride (Nal + Ca 2+; n = 6); (b) 0.2 mg/kg naloxone hydrochloride (Nal; n = 6); (c) 0.02 g/kg calcium borogluconate (Ca 2+; n = 5); (d) 0.1 ml/kg NaCl 0.9% (Saline; n = 5). All treatments were given as a single i.v. administration daily for 5 days. Blood was sampled every 20 min for 24 h during the acclimatization period (Day 0) and on the last day (Day 5) of treatment. In the first study (under maintenance), none of the treatments affected LH pulse frequency. In the second study (the lupin-supplemented rams), LH pulse frequency was significantly increased ( P < 0.05) by the administration of naloxone + Ca 2+, naloxone alone and Ca 2+ alone. Overall, rams on a low plane of nutrition showed the smallest response to naloxone, suggesting that an opioidergic mechanism is not involved in the suppressive effect of restricted nutrition on the gonadotrophic axis. Rather, because testosterone secretion was increased on the high plane of nutrition, the LH responses to naloxone are better explained by the effects of testosterone on opioidergic mechanisms. Finally, we failed to observe any interaction between opioids and calcium in the control of LH secretion.

$L^p$-estimates for the wave equation on the Heisenberg group

Let \mathcal L denote the sub-Laplacian on the Heisenberg group \mathbb H_m . We prove that e^{i\sqrt {–\mathcal L}} /(1 – \mathcal L)^{\alpha/2} extends to a bounded operator on L^p (\mathbb H_m) , for 1 ≤ p ≤ \infty , when \alpha &gt; (d–1) | 1/p – 1/2| .

Weights of the l-adic cohomology of a proper toric variety

We describe the weights of the l-adic cohomology groups of a toric variety over a finite field k in terms of the Ishida complexes of Z-modules. As a consequence, we conclude that, for an r-dimensional proper toric variety X, the m-th cohomology group Hm (X⊗k[kbar],Ql) is of pure weight if m = 0,1,2,3,2r - 3,2r - 2,2r - 1,2r.Furthermore, we show that, for any m such that 3 < m < 2r - 3,there exists an r-dimensional proper toric variety whose m-th cohomology group Hm (X⊗k[kbar],Q l ) is not pure.

Infinite chains of successive normalizers in the general linear group

Let K be a field of characteristics 0 or a field of characteristic 2 and of transcendence degree ≥1, and let G=GL(n, K) be the general linear group of degree n≥2 over K. Further, let $$ \leqslant \rho \leqslant \tfrac{{n^2 }}{4}$$ . It is proved that in G there exist chains of subgroups {Hm:m ∈ {, infinite in both directions, such that Hm<Hm−1, Hm−1 coincides with the normalizer NG(Hm), and every quotient group Hm−1/Hm is an elementary Abelian group of type (2,2,...,2) and of rank p. Bibliography: 7 titles.

Bone mineralization in former very low birth weight infants fed either human milk or commercial formula

The bone mineral status of former very low birth weight infants previously fed fortified human milk was evaluated during the posthospitalization period. Anthropometric measurements, bone mineral content, bone width, serum calcium, phosphorus, and albumin concentrations, and alkaline phosphatase activity were evaluated at 10, 16, and 25 postnatal weeks. Infants were fed either commercial formula or unfortified human milk after their hospital discharge. At 16 and 25 weeks postnatally, human milk-fed infants (group HM) had lower bone mineral content (P less than 0.01), bone mineral content/bone width ratio (p less than 0.01), serum phosphorus concentration (p less than 0.03), and higher alkaline phosphatase activity (p less than 0.01) than commercial formula-fed infants (group CM). Growth was similar in both groups. Bone mineral content was correlated positively to serum phosphorus (r = 0.52, p less than 0.05) and inversely to alkaline phosphatase activity (r = -0.63, p less than 0.01) at 25 weeks postnatally. The use of serum biochemical markers, however, could account for only 44% of the variability in bone mineral content. The exclusive feeding of human milk to very low birth weight infants after hospital discharge may place them at risk for mineral deficiencies.

Discrimination reaction performance as a function of anxiety and sex parameters.

From a sample of 681 college undergraduates 4 groups of 20 Ss of each sex (M, F), comparable in age and reasoning ability, were selected for low (L = 3 to 9) and high (H = 27 to 41) anxiety on the basis of Taylor MAS scores. All 80 Ss received 320 trials on the Air Force Discrimination Reaction Timer with nonspecific instructions designed to produce a high degree of task complexity. The results were as follows: (1) Group HF was slightly inferior in reaction speed ( Ra) to Group LF initially, superior later; (2) Group HM remained markedly inferior to Group LM throughout; (3) men were generally faster than women; (4) women were significantly more anxious pre-experimentally than men; (5) the main effects of Practice, Sex, and their interaction were significant, as predicted, but Anxiety was a clear decremental factor only among males; (6) mean acquisition curves for 4 augmented groups of 50 Ss each were exponential and also revealed a marginal Practice × Sex × Anxiety interaction. The equations fitted the Ra data with an average error of less than 1%, which is in excellent agreement with the Hull-Spence theory. Implications for prior research by Grice, Noble, Spence, and Taylor were discussed.

On the Cohomology Theory for Associative Algebras

The cohomology theory for associative algebras may be regarded as a superstructure built upon the classical representation theory. Let us consider an algebra 21 over a field 4. Suppose that we are given a finite dimensional linear space 3 over &1 which is simultaneously a representation space and an antirepresentation space for W. Then, to each element a of 21, there correspond two linear transformations u -* u -a and u a -u of A. If, in addition to the usual requirements, these transformations commute with each other, i.e. if a,(ua2) = (a,-u)-a2, for all a1, a2 e 21 and all u e $, we say that $ is an 2-module. The notions of the cohomology theory are based on this set-up, as follows: The set of all m-linear mappings of 21 into $, when regarded as an additive group in the usual way, is called the group of the m-dimensional $-cochains (or (m, $)-cochains) of W. We shall denote it by Cm(2f, p). The group C'(21, p) is identified with the additive group of p. The coboundary operator, 6, as defined by Eilenberg and MacLane, maps each Cm(21, p) linearly into Cm'+(2t, p), as follows: Let f e Cz'(, p), a,, *, am e W; then (6f) {a, , amA} = a, f{aI, * * 7 am?, + Z-m~n (-l~tf{ai, ** *, a~aai +, *, a.+,} + (1)m+lf{ai, am am,+. For any cochain f, we have 6(6f) = 0. Hence the cohomology groups may be defined by the well known procedure of combinatorial topology. An element f E Cm(?2, p) is called an m-dimensional cocycle if cf = 0. An element of the form (5g, where g e Cml(2[, p) is called an m-dimensional coboundary. These form a subgroup B'(2, p) of the group Zm(2, p) of the m-dimensional cocycles. The m-dimensional cohomology group Hm(2, p) is defined as the quotient group Zm(21, p)/Bm(21, p). For m = 1 and m = 2, these groups have been interpreted with reference to classical notions of structure in a previous paper.' Although no such interpretation has as yet been found for the higher dimensional groups it is possible to make a rough forecast of the r6le which the cohomology theory will play in the study of the structure of algebras. There is good evidence that it will provide appropriate methods for investigating a variety of structural characteristics which seem to lie outside the domain of the classical representation theory. The trend which takes its logical departure in Wedderburn's structure theorems has been to intensity and refine the structural analysis only at the level of maximal regularity.2 Thus, the radical of an algebra is split off by Wedder-