bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on the nutrition of marine flatfish. Utilization of various dietary proteins by plaice (Pleuronectes platessa)
Authors: Cowey C. B. , Adron J. , Blair A. , Shanks Aileen M.
Published: May 2005

1. Five proteins, freeze-dried cod muscle, a white fish meal, a yeast-protein concentrate, a soya protein and a fish-protein concentrate (a solvent-extracted fish meal) were given separately, as single sources of protein in diets containing 500g crude protein/kg, to small plaice (Pleuronectes platessa) of mean initial weight 12–15g. Weight gain and net protein utilization (NPU) were examined.

2. Even at these high protein intakes, significant differences in growth rate between fish given the different proteins were evident. These findings were reflected in different NPU values between the proteins. This position contrasts with that in the rat where proteins which differ markedly in NPU at low protein intakes have similar NPU values when given at high dietary levels.

3. Coefficients of apparent digestibility measured on larger plaice (150–200g) were high for all the proteins used except soya-bean meal, which had a digestibility coefficient of 0.68.

4. At high protein intakes there was no clear relationship between NPU values and essential amino acid content (as measured chemically) of the proteins tested.

5. The preparation of protein concentrates from fatty fish by the use of detergents is described. One of the preparations obtained gave weight gains and NPU values similar to those obtained with commercially available feedstuff proteins.
The utilization of protein and excretion of uric acid in germ-free and conventional chicks
Authors: Salter D. N. , Coates Marie E. , Hewitt D.
Published: May 2005

1. The influence of the gut microflora on protein utilization has been investigated with a series of good- and poor-quality protein diets in germ-free (GF) and conventional (CV) chicks by the measurement of net protein utilization (NPU) and uric acid excretion.

2. The diets used were: 280 g protein per kg diet containing unheated or heat-damaged albumen (100 g/kg), casein (80 g/kg) and gelatin (100 g/kg); sesame protein (220 g/kg); sesame protein (220 g/kg) supplemented with lysine (5 g/kg); freeze-dried cod muscle (160 g/kg); heat-damaged cod muscle (160 g/kg); mildly-steamed egg albumen (100g/kg); heat-damaged egg albumen (100 g/kg).

3. No significant differences in NPU values for the proteins measured in GF and CV chicks were found, with the exception of unsupplemented sesame protein, for which the NPU value was slightly higher in GF chicks.

4. The replacement of unheated egg albumen by heat-damaged egg albumen in the 280 g protein/kg diet resulted in a decrease in uric acid excretion. With the cod-muscle diets, heat-damaging the protein caused an increase in uric acid excretion. Supplementing the sesame protein with lysine resulted in a decrease in uric acid excretion.

5. Excretion of uric acid tended to be higher in CV chicks than in GF chicks with all proteins except sesame protein, with which uric acid excretion was a little higher in GF chicks.

6. Endogenous nitrogen excretion was higher in GF than in CV chicks.

7. It is concluded that the gut microflora has little influence on the utilization of dietary protein by chicks, although it may modify the route of excretion of the N which survives digestion and reaches the lower gut.
The determinatio of tryptophan in purified proteins and in feeding-stuffs
Authors: Matheson N. A.
Published: May 2005

1. A method was developed for the estimation of tryptophan in purified proteins or in feeding-stuffs. Samples were hydrolysed by autoclaving them with barium hydroxide in polypropylene flasks or tubes. Excess Ba was precipitated as the hydroxide by cooling, and hydrogen sulphide formed during hydrolysis was removed under reduced pressure. Tryptophan was assayed colorimetrically with dimethylaminobenzaldehyde by comparison with tryptophan standards carried through the complete procedure.

2. The method was applied to purified proteins, to analysed materials and to a wide range of samples. Results agreed fairly well with published values for purified proteins, though rather less well for the samples analysed by other workers. Reasons are discussed. The samples examined gave results in the expected range.
Effects of organic and inorganic sulphur on the availability of dietary copper to sheep
Authors: Suttle N. F.
Published: May 2005

1. The effects of dietary sulphur on the availability of dietary copper were estimated by means of a repletion technique. The responses of initially hypocupraemic ewes to repletion with Cu-supplemented diets containing supplements of organic S, as methionine, and of inorganic S, as Na2SO4, were compared with those obtained with a diet low in S.

2. The two forms of S had similar effects. Responses in plasma Cu were reduced by 39–56 % when S was increased from 1.0 to 3.0 or 4.0 g/kg diet and the availability of dietary Cu was estimated to have decreased from 0.062 to 0.041. Both S supplements produced marked increases in rumen sulphide concentrations.

3. Dietary S had no effect on plasma Cu when added to the low-Cu diet of hypocupraemic ewes being repleted by a continuous intravenous infusion of Cu.

4. The addition of CuS, providing 5 mg Cu/kg, to the diet of hypocupraemic ewes produced no response in plasma Cu or haemoglobin. The same amount of Cu, given as CuSO4, increased plasma Cu by 0.46±0.15 mg/l and haemoglobin by 33±3.8 g/l after 36 d: the subsequent replacement of CuSO4by CuS induced hypocupraemia again but had no effect on haemoglobin.

5. It was concluded that variations in dietary S within the normal range for herbage exert an independent effect on Cu metabolism, possibly through the formation of insoluble CuS at sites beyond the rumen.
The influence of the gut microflora on the digestion of dietary and endogenous proteins: studies of the amino acid composition of the excreta of germ-free and conventional chicks
Authors: Salter D. N. , Fulford Rosemary J.
Published: May 2005

1. To assess the part played by the microflora in the digestion of proteins, the amino acid composition of the excreta and the apparent and true digestibilities of individual amino acids were measured in germ-free (GF) and conventional (CV) chicks.

2. Three diets were used: diet 1, nitrogen-free; diet 2,280 g protein/kg as (g/kg): casein 80, gelatin 100 and freeze-dried egg albumen 100 and diet 3,280 g protein/kg as diet 2 but with heat-damaged instead of freeze-dried egg albumen. Half of the GF and half of the CV chicks received the N-free diet in the first 7 d of test and the other half of each group received either diet 2 or diet 3. In the second 7 d test period those chicks which had been given the N-free diet received either diet 2 or diet 3 while those which had been given protein diets received the N-free diet. Total amino acids were measured in hydrolysates of the soluble and insoluble fractions of the excreta collected in the last 3 d of each test period.

3. The amino acid composition of the soluble fraction of the excreta of chicks given either diet 2 or diet 3 differed markedly from that of chicks given the N-free diet. The amino acid composition of the insoluble fraction of the excreta of chicks given diet 2 was similar to that of chicks given the N-free diet, whereas that of chicks given diet 3 was markedly different and resembled egg albumen in composition.

4. In the soluble fraction of excreta from CV chicks given diets 1 and 2 the proportions of threonine, serine and glucosamine were lower and those of methionine, leucine, isoleucine and phenylalanine were higher than in those from GF chicks, particularly on diet 1. In the insoluble fraction of excreta from CV chicks given these two diets, compared with GF chicks, there were lower proportions of serine and proline and higher proportions of cysteic acid and lysine, the latter particularly with diet 1.

5. Lower proportions of threonine, serine and glucosamine were also observed in the soluble fractions of excreta from the CV chicks given diets 1 and 3, compared with GF chicks, whereas the proportion of glutamic acid was higher. With these two diets the insoluble fraction from CV chicks contained a higher proportion of alanine. In each instance the environmental effect was greater with diet 1.

6. No effect of environment on either apparent or true digestibility of individual dietary protein amino acids was demonstrated, with the exception of threonine in diet 2, the true digestibility of which was higher in GF than in CV chicks.

7. It was concluded that the gut microflora of the chick had little influence on the digestion of the proteins in the diets tested, but may serve an important role in the degradation of endogenous proteins and the recycling of N.
The effect of pregnancy and lactation on food intake, gastrointestinal anatomy and the absorptive capacity of the small intestine in the albino rat
Authors: Cripps A. W. , Williams V. J.
Published: May 2005

1. Food consumption, live weight, anatomical measurements on the gut organs and the absorptive capacity of the small intestine for L-leucine and D(+)-glucose were made on virgin (control), pregnant and lactating albino rats.

2. Food intake increased by approximately 60% during pregnancy and a further 250% during lactation.

3. Pregnancy did not markedly influence the gross anatomy of the gastrointestinal tract. There was evidence for increased villus height and percentage water in the small intestine and for increased length of the colon during pregnancy.

4. During lactation, the alimentary canal progressively increased in weight and size. It partially regressed following weaning.

5. All anatomical measurements, except the length of the small intestine, completely regressed to control values within 20 d of weaning. The increased intestinal length had not completely regressed by day 30 post-weaning.

6. No significant change was observed in absolute absorption of glucose or leucine during pregnancy.

7. Absolute absorption of leucine and of glucose was increased during lactation. Greatest absorption occurred on the 10th day of lactation.

8. Results for absorption of leucine and glucose per unit length indicated that the ability of the mucosal cells to absorb or the number of absorptive cells/mm had changed during lactation and the post-lactation periods.
Potassium supplementation, serum immunoreactive insulin concentrations and glucose tolerance in protein-energy malnutrition
Authors: Mann M. D. , Becker Dorothy J. , Pimstone B. L. , Hansen J. D. L.
Published: May 2005

1. The serum immunoreactive insulin (IRI) concentrations, and glucose disappearance rate-constants after intravenous glucose administration were measured on admission and during recovery in children suffering from protein-energy malnutrition (PEM).

2. A high potassium intake resulted in a considerable increase in the serum IRI levels early in the treatment period. There was a definite relationship between potassium depletion and many measurements of insulin secretion.

3. The results are consistent with the hypothesis that impaired insulin release in children suffering from PEM is partly the result of potassium depletion.
Solubility and net exchange of calcium, magnesium and phosphorus in digesta flowing along the gut of the sheep
Authors: Ben-Ghedalia D. , Tagari H. , Zamwel S. , Bondi A.
Published: May 2005

1. The changes in the solubility of calcium, magnesium and phosphorus in digesta flowing along the intestinal tract and the net movement across the intestinal wall of these elements were determined in six rams, each equipped with three T-shaped cannulas; cannulas were placed in a total of six different sites of the small intestine. Cr2O3 was used as a marker substance to measure the rate of flow of the digesta.

2. The concentrations of soluble Ca, Mg and P decreased as digesta moved along the intestine. The greatest fall in soluble Ca occurred after the first 3 m of the intestine, while a significant decrease in soluble Mg was found only at 15 and 25 m from the pylorus. The concentration of soluble P in digesta decreased until the 7 m site and then remained stable. In the faeces, the level of soluble Mg was approximately 4 times higher than, and that of Ca equal to, the levels of Mg and Ca found in digesta flowing through the upper intestine. Unlike Ca and Mg, a very low concentration of soluble P was found in the faeces.

3. In the duodenum, 84, 78 and 62% of the total Ca, Mg and P respectively were soluble, whereas in the digesta flowing through the terminal ileum the corresponding values were 3·2, 7·2 and 19% for Ca, Mg and P respectively.

4. The forestomachs and the colon were found to be the main sites of Mg net absorption; 1·12 mmol/h was apparently absorbed from the stomach and 1·05 mmol/h from the colon. The upper small intestine (1–3 m from the pylorus) appeared to be the major site of Ca and P absorption.

5. In the last 10 m of the small intestine, considerable amounts of minerals were secreted; 4·70, 0·96 and 1·85 mmol Ca, Mg and P/h respectively were added to the digesta flowing between 15 and 25 m from the pylorus. The effect of the increase in the pH of digesta along the small intestine on the solubility of these minerals is discussed.
Jejunal absorption of an amino acid mixture simulating casein and an enzymic hydrolysate of casein prepared for oral administration to normal adults
Authors: Silk D. B. A. , Clark M. L. , Marrs T. C. , Addison Jill M. , Burston D. , Matthews D. M. , Clegg K. Mary
Published: May 2005

1. An intestinal perfusion technique was used in six normal human subjects to study absorption of sixteen individual amino acids from an amino acid mixture simulating casein and from an enzymic hydrolysate of casein, prepared for oral administration to these subjects, which consisted of a mixture of oligopeptides and free amino acids.

2. Total absorption of α-amino nitrogen was greater from the casein hydrolysate than from the amino acid mixture, and the considerable variation in percentage absorption of individual amino acids from the amino acid mixture was much reduced when the enzymic hydrolysate solution was perfused, as a number of amino acids which were poorly absorbed from the amino acid mixture were absorbed to a greater extent from the casein hydrolysate.

3. These findings indicate that after extensive intestinal resections or in malabsorption there might be significant nutritional advantages in the administration of protein hydrolysates rather than amino acid mixtures.
Maintenance requirements for energy in cross-bred cattle
Authors: Patle B. R. , Mudgal V. D.
Published: May 2005

1. Twenty-seven energy and protein balances were done using nine cross-bred (Brown Swiss × Sahiwal) mature bullocks in a series of three balance trials. The bullocks were fed 75, 100 and 125 % of the metabolizable energy (ME) and digestible crude protein standard values recommended by the (US) National Research Council (1966). Heat production was estimated by indirect calorimetry, by collection and analysis of respiratory gases

2. Utilization of energy for maintenance and fat production was estimated by computing regression of energy balance v. digestible energy (DE) and ME separately on a metabolic body size (kg body-weight (W)0·75) basis. Maintenance energy requirements and efficiency of utilization of ME for lipogenesis were estimated using multiple regression of ME intake, also. Heat production (and thus energy balance) was corrected for excess nitrogen intake

3. An attempt was made to measure basal heat production of bullocks so that the net energy requirements for maintenance could be estimated. Extrapolation of the regression line of energy balance v. ME intake below maintenance on a W0·75 basis gave a basal metabolism of 348·09 kJ/W0·75 per d

4. Energy requirements for maintenance were (kJ/kg W0·75 per d): 539·43 DE, 448·81 ME and 348·09 net energy. The results of multiple regression gave a requirement of 432·15 kJ ME/kg W0·75 per d for maintenance

5. The efficiency of utilization of ME for maintenance was 81·34% while for lipogenesis it was 54·5 %.
The effects of short periods of fasting on the absorption of heavy metals
Authors: Quarterman J. , Morrison Elaine
Published: May 2005

1. Rats were deprived of food for periods of from 0 to 40 h and then given203Pb,203Hg.59Fe,64Cu.64Zn or45Ca by stomach tube. The absorption and retention of these metals in tissues was measured 1 h and 2 d after dosing.

2. After 16–24 h of food deprivation between two and ten times more metal was retained than after 0–12 h.

3. The effects of length of fast on metal uptake by the intestinal mucosa were greatest in the duodenum.

4. Lactale production by duodenal mucosa was halved after 12 h of food deprivation but galactose absorption was little changed after a 40 h fast.
Nitrogen balance in Indian preschool children receiving the safe level of protein at varying levels of energy
Authors: Iyengar Ashok K. , Rao B. S. Narasinga , Reddy Vinodini
Published: May 2005

1. A study was carried out to determine the effects of varying the level of energy intake on nitrogen balance in preschool children receiving the safe requirement level of protein, determined in an earlier study.

2. Seven preschool children received four energy levels, i.e. 293, 334, 376 and 418kJ/kg body-weight at the safe level of protein intake of 1·75 g/kg body-weight and N balance determined.

3. The N balance decreased with a decrease in energy intake. However, the N balance was positive at all levels of energy intake studied.

4. Results indicated that at a protein intake of 1·75 g/kg body-weight the minimum level of energy intake for a retention of 40 mg N/kg body-weight in these children was found to be 326·2±45·5 (mean ± SD) kJ/kg body-weight. Below this energy intake the safe level of protein intake became inadequate.
Wheat bran increases high-density-lipoprotein cholesterol in the rat
Authors: Asp N.-G. , Bauer H. G. , Nilsson-Ehle P. , Nyman Margareta , Öste R.
Published: May 2005

1. Five groups of male Sprague Dawley rats were given for 6 months a diet with high protein and fat contents but a very low dietary fibre content (group B), and this diet mixed with (g/kg) 50 low-methoxyl pectin (groupL), 50 high-methoxyl pectin (group H), 50 guar gum (group G) and 200 wheat bran (group WB, corresponding to 100 wheat fibre) respectively.

2. The weight increment was significantly lower in group G than in the other groups. Assuming no energy value of the dietary fibre, the weight increment (/kJ) was the same in groups B, L and H, lower in group G and higher in group WB, indicating that a proportion of the bran fibre might in fact be available as a source of energy.

3. Wheat bran increased total plasma cholesterol and high-density-lipoprotein cholesterol after 6, 12 and 26 weeks. Group G had significantly lowered plasma cholesterol after 12 weeks. Pectin on the other hand did not significantly influence total or HDL-cholesterol levels. It is therefore possible that the plasma cholesterol lowering effect of pectin previously demonstrated in the rat is dependent on the presence of significant amounts of dietary cholesterol as our diets did not contain added cholesterol. Plasma triglycerides decreased with age but were similar in all groups.
Differences in body compositions, growth and food intakes between mice which have been selected for a small and large body size
Authors: Rucklidge Garry J.
Published: May 2005

1. Q-strain mice selected for high (QLF) or low (QSC) body-weight at 6 weeks of age were compared with respect to their body-weight increases, gross body compositions and food intakes.

2. DNA, RNA, protein and hydroxyproline contents were measured.

3. QLF animals were larger at all stages of development but ate more food and gained more body-weight per unit food intake with an apparently improved efficiency of utilization compared with QSC mice.

4. The efficiency of deposition of dietary energy in Q-strain mice was found to be significantly lower than that of other growing mammals receiving similar energy intakes.

5. Body water, protein and fat of both strains were similar at birth and at 42 d of age but the contribution of fat to body-weight in the preweaning phase was greater for QLF while QSC accreted more fat per unit weight gain in the postweaning period.

6. An increase in cell number made a greater contribution to the growth post partum of the QLF mice, but by 42 d of age little difference between the number of cells per unit weight in the two strains was evident.

7. Despite increases in RNA concentrations at all stages of development, of QLF mice compared with QSC, measurements of body composition do not indicate any accompanying increases of protein concentration in these animals.
An investigation of the effects of intravenous administration of thiomolybdate on copper metabolism in chronic Cu-poisoned sheep
Authors: Gooneratne S. R. , Howell J. McC. , Gawthorne J. M.
Published: May 2005

1. Fourteen sheep were dosed repeatedly with a solution of copper sulphate (2 g/l) in order to induce chronic copper poisoning and four similar undosed animals acted as controls.

2. Thiomolybdate (TM) was intravenously administered to all control sheep and to all except two of the test sheep. A variety of biochemical factors were studied before and after injections of TM.

3. The direct-reacting Cu, whole-blood Cu and plasma Cu concentrations were elevated in animals given TM injections and at the ‘haemolytic crisis’ of untreated chronic Cu-poisoned animals. But most of the increased Cu observed on injecting TM was insoluble in trichloroacetic acid (TCA) and did not enter erythrocytes. The results indicate that uptake of Cu by erythrocytes is essential for haemolysis to occur and that for this to happen the Cu must be in a direct reacting, TCA-soluble form.

4. Increased amounts of Cu were excreted in the urine at haemolysis and at the commencement of TM injections. High levels of direct-reacting Cu were found in plasma at these times.

5. Marked changes were not found in caeruloplasmin activity, packed cell volume or the osmotic fragility of erythrocytes except at haemolysis. TM injections did not alter these factors in any of the sheep studied.
The maximum capacity of the liver of the adult dairy cow to metabolize ammonia
Authors: Symonds H. W. , Mather Denise L. , Collis K. A.
Published: May 2005

1. Three adult dairy cows were fitted with cannulas in a mesenteric, portal, hepatic and jugular vein and a carotid artery. They received infusions of step-wise increasing amounts of ammonia as ammonium acetate via a mesenteric vein until NH3 intoxication occurred. Sodium acetate was used in control infusions. The maximum rate of uptake of NH3 by the liver and the concentrations of glucose, urea, lactate, acetate and bilirubin in blood were measured.

2. During the infusions of ammonium acetate the liver extracted almost all the NH3 present in the portal vein until an infusion rate of approximately 15·0 mmol/min was reached. The maximum capacity of the liver to remove NH3 during its first pass was on average 1·84 mmol/min per kg wet weight. The cows became intoxicated when arterial plasma ammonia concentrations reached 0·8 mmol/1. Concentrations of NH3 in jugular venous blood were between 66 and 74% of those in the carotid.
The effect of low dietary manganese intake on rainbow trout (Salmo gairdneri)
Authors: Knox D. , Cowey C. B. , Adron J. W.
Published: May 2005

1. Rainbow trout (Salmo gairdneri) of mean initial weight 15 g were given either a low-manganese or control diet containing 1·3 and 33 mg Mn/kg dry diet respectively.

2. Weight gains over a 24-week feeding period were the same for both groups of trout.

3. Hepatosomalic index, blood packed cell volume and haemoglobin concentration, plasma protein and the activities of aspartic aminotransferase(EC2.6.1.1)and alanine aminotransferase(EC2.6.1.2) were unaffected by dietary Mn intake.

4. Plasma potassium and iron levels were increased in the trout given the low-Mn diet.

5. The hepatic levels of magnesium, sodium, K, zinc, copper, Mn and phosphorus were significantly reduced in the fish given the low-Mn diet.

6. In those trout given the low-Mn diet the levels of Mn and calcium in the vertebral ash were significantly reduced.

7. The hepatic activity of Cu-Zn superoxide dismutase (EC1.15.1.1; Cu–ZnSOD) and of Mn superoxide dismutase (EC1.15.1.1; MnSOD) in cardiac muscle and liver was reduced in the group of trout given the low-Mn diet. The fall in Cu–ZnSOD and MnSOD activities coincided with reduced tissue levels of their respective metal components.
Effects of removal of the forestomach and caecum on the utilization of dietary urea in golden hamsters (Mesocricetus auratus) given two different diets
Authors: Sakaguchi Ei , Itoh Junichi , Shinohara Hisashi , Matsumoto Tatsuro
Published: May 2005

1. Surgical removal of the forestomach, the caecum or both the forestomach and the caecum, was performed on growing male golden hamsters (Mesocricetus auratus) given a low-or high-fibre diet.

2. In Expt J, 18 d after surgery, the hamsters which were given a concentrate before surgery were given an experimental low-fibre diet containing urea or [15N]urea (10 g/kg diet) for 9 d. In Expt 2, 5 d after surgery, the hamsters which were given a forage diet before surgery were adapted to an experimental high-fibre diet containing urea (10 g/kg) and dried Italian ryegrass (Lolium italicum) powder (400 g/kg diet) for 5 d, and 10 d after surgery, given a diet containing [l5N]urea (10 g/kg diet) for 9 d.

3. In both experiments, removal of the caecum resulted in a significant lowering of both weight-gain and the digestibility of the dry matter, and removal of the forestomach resulted in a significant decrease of both accumulation of15N in the body protein and proportion ofl5N retained in the body protein as a proportion of the administered dosage.

4. The effect of removal of the caecum on the utilization of [15N]urea was not apparent in Expt 1, but the utilization of [15N]urea was significantly lowered by removal of the caecum in Expt 2.

5. These results suggest that the caecum may play a more important role in food utilization than the forestomach. However, the forestomach of the golden hamster plays a significant role in the utilization of dietary urea. It is presumed that the role of the caecum in the utilization of urea may vary under different dietary conditions.
Histone modifications affect timing of oligodendrocyte progenitor differentiation in the developing rat brain
Authors: Shen Siming , Li Jiadong , Casaccia-Bonnefil Patrizia
Published: May 2005

Timely differentiation of progenitor cells is critical for development. In this study we asked whether global epigenetic mechanisms regulate timing of progenitor cell differentiation into myelin-forming oligodendrocytes in vivo. Histone deacetylation was essential during a specific temporal window of development and was dependent on the enzymatic activity of histone deacetylases, whose expression was detected in the developing corpus callosum. During the first 10 postnatal days, administration of valproic acid (VPA), the specific inhibitor for histone deacetylase activity, resulted in significant hypomyelination with delayed expression of late differentiation markers and retained expression of progenitor markers. Differentiation resumed in VPA-injected rats if a recovery period was allowed. Administration of VPA after myelination onset had no effect on myelin gene expression and was consistent with changes of nucleosomal histones from reversible deacetylation to more stable methylation and chromatin compaction. Together, these data identify global modifications of nucleosomal histones critical for timing of oligodendrocyte differentiation and myelination in the developing corpus callosum.
Heart Rate Variability Predicts Severe Hypotension after Spinal Anesthesia for Elective Cesarean Delivery
Authors: Hanss Robert , Bein Berthold , Ledowski Thomas , Lehmkuhl Marlies , Ohnesorge Henning , Scherkl Wiebke , Steinfath Markus , Scholz Jens , Tonner Peter H.
Published: May 2005

Background

Hypotension due to vasodilation during subarachnoid block (SAB) for elective cesarean delivery may be harmful. Heart rate variability (HRV), reflecting autonomic control, may identify patients at risk of hypotension.

Methods

Retrospectively, HRV was analyzed in 41 patients who were classified into one of three groups depending on the decrease in systolic blood pressure (SBP): mild (SBP > 100 mmHg), moderate (100 > SBP > 80 mmHg), or severe (SBP < 80 mmHg). Prospectively, HRV and hemodynamic data of 19 patients were studied. Relative low frequency (LF), relative high frequency (HF), and LF/HF ratio were analyzed.

Results

Retrospective analysis of HRV showed a significantly higher sympathetic and lower parasympathetic drive in the groups with moderate and severe compared with mild hypotension before SAB (median, 25th/75th percentiles): LF/HF: mild: 1.2 (0.9/1.8), moderate: 2.8 (1.8/4.6), P < 0.05 versus mild; severe: 2.7 (2.0/3.5), P < 0.05 versus mild. Results were confirmed by findings of LF and HF. Prospectively, patients were grouped according to LF/HF before SAB: low-LF/HF: 1.5 (1.1/2.0) versus high-LF/HF: 4.0 (2.8/4.7), P < 0.05; low-LF: 58 +/- 9% versus high-LF: 75 +/- 10%, P < 0.05; low-HF: 41 +/- 10% versus high-HF: 25 +/- 10%, P < 0.05. High-risk patients had a significantly lower SBP after SAB (76 +/- 21 vs. 111 +/- 12 mmHg; P < 0.05).

Conclusions

Retrospectively analyzed HRV of patients scheduled to undergo elective cesarean delivery during SAB showed significant differences depending on the severity of hypotension after SAB. Preliminary findings were prospectively confirmed. High LF/HF before SAB predicted severe hypotension. Preoperative HRV analysis may detect patients at risk of hypotension after SAB.
Prolongation of QTc Interval after Postoperative Nausea and Vomiting Treatment by Droperidol or Ondansetron
Authors: Charbit Beny , Albaladejo Pierre , Funck-Brentano Christian , Legrand Mathieu , Samain Emmanuel , Marty Jean
Published: May 2005

Background

At dosages above 0.1 mg/kg, droperidol induces a dose-dependent QTc interval prolongation. Although subject to controversy, low-dose droperidol has recently been suspected to induce cardiac arrhythmias. Hence, 5-hydroxytryptamine type 3 antagonists have become the first-line drug for management of postoperative nausea and vomiting. These drugs are also known to prolong the QTc interval at high dosages. This study describes QTc interval changes associated with postoperative nausea and vomiting treatment by droperidol or ondansetron at low doses.

Methods

Eighty-five patients with postoperative nausea and vomiting were included in this prospective, single-blind study. Patients received either 0.75 mg intravenous droperidol (n = 43) or 4 mg intravenous ondansetron (n = 42). Electrocardiographic recordings were obtained before administration of antiemetic drug and then 1, 2, 3, 5, 10, and 15 min after. Electrocardiographic monitoring was maintained for 3 h in eight patients in each group.

Results

The QTc interval was prolonged (> 450 ms in men, > 470 ms in women) in 21% of the patients before antiemetic drug administration. This was significantly correlated with lower body temperature and longer duration of anesthesia. Compared with predrug QTc measurement, both antiemetics were associated with a significant QTc interval prolongation (P < 0.0001). The mean maximal QTc interval prolongation was 17 +/- 9 ms after droperidol occurring at the second minute and 20 +/- 13 ms after ondansetron at the third minute (both P < 0.0001). Compared with predrug measurement, the QTc interval was significantly lower after the 90th minute in both groups.

Conclusions

Droperidol and ondansetron induced similar clinically relevant QTc interval prolongations. When used in treatment of postoperative nausea and vomiting, a situation where prolongation of the QTc interval seems to occur, the safety of 5-hydroxytryptamine type 3 antagonists may not be superior to that of low-dose droperidol.
Pharmacokinetics and Pharmacodynamics of Mivacurium in Patients Phenotypically Homozygous for the Atypical Plasma Cholinesterase Variant
Authors: Østergaard Doris , Viby-Mogensen Jørgen , Rasmussen Søren N. , Gätke Mona R. , Varin France
Published: May 2005

Background

In patients homozygous for atypical plasma cholinesterase, mivacurium causes a long-lasting neuromuscular block, but injection of human cholinesterase has been proven effective in antagonizing the block. The purpose of this study was to evaluate the pharmacodynamics and pharmacokinetics of mivacurium in such patients, as well as the effect of cholinesterase injected early or late after mivacurium.

Methods

Eleven patients phenotypically homozygous for the atypical variant received 0.075 mg/kg (1 patient) or 0.15 mg/kg (10 patients) mivacurium. The neuromuscular block was monitored using train-of-four nerve stimulation and mechanomyography. Cholinesterase, 2.8-10.0 mg/kg, was administered approximately 30 or 120 min after mivacurium. The times to different levels of neuromuscular recovery and the venous concentrations of the isomers of mivacurium were measured.

Results

Injection of cholinesterase increased plasma cholinesterase activity to normal and the clearances of the active isomers and the elimination rate constants by a factor of 10-15. The first response was seen in 13.5 min (3.7-44.2 min). Time to a train-of-four ratio of 0.8 ranged from 30 to 60 min (n = 6). Neostigmine injected after cholinesterase shortened recovery further, and a train-of-four ratio of 0.8 was reached in 10-30 min.

Conclusion

As expected, the duration of action of mivacurium is markedly prolonged in homozygous atypical patients. Injection of cholinesterase significantly increases the metabolism of mivacurium, leading to a shorter duration of action. Injection of neostigmine after the administration of cholinesterase speeds up recovery.
Severe Pulmonary Hypertension during Pregnancy
Authors: Bonnin Martine , Mercier Frédéric J. , Sitbon Olivier , Roger-Christoph Sandrine , Jaïs Xavier , Humbert Marc , Audibert François , Frydman René , Simonneau Gérald , Benhamou Dan
Published: May 2005

Background

Available literature on pregnant women with severe pulmonary hypertension (PH) relies mainly on anecdotal case reports and two series only.

Methods

The authors reviewed the charts of all pregnant women with severe PH who were followed up at their institution during the past 10 yr, to assess the multidisciplinary treatment and outcome of these patients.

Results

Fifteen pregnancies in 14 women with severe PH were managed during this period: There were 4 cases of idiopathic pulmonary arterial hypertension (PAH), 6 cases of congenital heart disease-associated PAH, 1 case of fenfluramine-associated PAH, 1 case of mixed connective tissue-associated PAH, 1 case of human immunodeficiency virus-associated PAH, and 2 cases of chronic thromboembolic PH. PH presented during pregnancy in 3 patients. Two patients died before delivery at 12 and 23 weeks' gestation. Four patients had vaginal deliveries with regional anesthesia: One died 3 months postpartum, one worsened, and two remained stable. Four had cesarean deliveries during general anesthesia: One died 3 weeks postpartum, one worsened, and two remained stable. Five had cesarean deliveries during low-dose combined spinal-epidural anesthesia: One died 1 week postpartum, and four remained stable. There were two fetal deaths: one related to therapeutic abortion at 21 weeks' gestation and one stillbirth at 36 weeks' gestation followed by the death of the mother 1 week later.

Conclusions

Despite the most modern treatment efforts, the maternal mortality was 36%. Scheduled cesarean delivery during combined spinal-epidural anesthesia seemed to be an attractive approach, but there was no evidence of actual benefit. Therefore, pregnancy must still be discouraged in patients with severe PH.
Effect of Nicotine Replacement Therapy on Stress and Smoking Behavior in Surgical Patients
Authors: Warner David O. , Patten Christi A. , Ames Steven C. , Offord Kenneth P. , Schroeder Darrell R.
Published: May 2005

Background

Many surgical patients are dependent on nicotine. Smoke-free policies in healthcare facilities mandate abstinence from smoking, which could contribute to psychological stress in the perioperative period. The authors tested the hypothesis that nicotine replacement therapy decreases psychological stress in cigarette smokers scheduled to undergo elective surgery and determined whether nicotine replacement therapy affects postoperative smoking behavior, even when not specifically prescribed to promote abstinence.

Methods

In this double-blind, placebo-controlled trial, 121 smokers, of whom 116 received a study intervention, were randomly assigned to receive either active (nicotine-containing) or placebo patches, beginning on the morning of surgery and continuing for up to 30 days after discharge from the hospital. Outcomes included the Perceived Stress Score, the Nicotine Withdrawal Score, and subject self-report of smoking behavior.

Results

The Perceived Stress Score and the Nicotine Withdrawal Score did not change significantly from baseline over the immediate perioperative period and did not differ between active or placebo patch groups (all P > 0.19). The percentage of placebo versus active patch subjects reporting 7-day abstinence at 30 days postoperatively (30% vs. 39%; P = 0.29) did not differ significantly between groups. At 30 days postoperatively, subjects in both groups significantly reduced their cigarettes smoked per day from baseline, but those receiving active patches reported a greater decrease (a mean decrease of 11 +/- 11 vs. 15 +/- 7 cigarettes/day in placebo and active groups; P = 0.045).

Conclusion

Routine nicotine replacement therapy is not indicated in smokers undergoing surgery for the purposes of managing nicotine withdrawal and stress but can modify some aspects of postoperative smoking behavior.
Volatile Anesthetics Induce Caspase-dependent, Mitochondria-mediated Apoptosis in Human T Lymphocytes In Vitro
Authors: Loop Torsten , Dovi-Akue David , Frick Michael , Roesslein Martin , Egger Lotti , Humar Matjaz , Hoetzel Alexander , Schmidt Rene , Borner Christoph , Pahl Heike L. , Geiger Klaus K. , Pannen Benedikt H. J.
Published: May 2005

Background

Volatile anesthetics modulate lymphocyte function during surgery, and this compromises postoperative immune competence. The current work was undertaken to examine whether volatile anesthetics induce apoptosis in human T lymphocytes and what apoptotic signaling pathway might be used.

Methods

Effects of sevoflurane, isoflurane, and desflurane were studied in primary human CD3 T lymphocytes and Jurkat T cells in vitro. Apoptosis and mitochondrial membrane potential were assessed using flow cytometry after green fluorescent protein-annexin V and DiOC6-fluorochrome staining. Activity and proteolytic processing of caspase 3 was measured by cleaving of the fluorogenic effector caspase substrate Ac-DEVD-AMC and by anti-caspase-3 Western blotting. Release of mitochondrial cytochrome c was studied after cell fractionation using anti-cytochrome c Western blotting and enzyme-linked immunosorbent assays.

Results

Sevoflurane and isoflurane induced apoptosis in human T lymphocytes in a dose-dependent manner. By contrast, desflurane did not exert any proapoptotic effects. The apoptotic signaling pathway used by sevoflurane involved disruption of the mitochondrial membrane potential and release of cytochrome c from mitochondria to the cytosol. In addition, the authors observed a proteolytic cleavage of the inactive p32 procaspase 3 to the active p17 fragment, increased caspase-3-like activity, and cleavage of the caspase-3 substrate poly-ADP-ribose-polymerase. Sevoflurane-induced apoptosis was blocked by the general caspase inhibitor Z-VAD.fmk. Death signaling was not mediated via the Fas/CD95 receptor pathway because neither anti-Fas/CD95 receptor antagonism nor FADD deficiency or caspase-8 deficiency were able to attenuate sevoflurane-mediated apoptosis.

Conclusion

Sevoflurane and isoflurane induce apoptosis in T lymphocytes via increased mitochondrial membrane permeability and caspase-3 activation, but independently of death receptor signaling.
Effect of Sleep Deprivation on Righting Reflex in the Rat Is Partially Reversed by Administration of Adenosine A1 and A2 Receptor Antagonists
Authors: Tung Avery , Herrera Stacy , Szafran Martin J. , Kasza Kristen , Mendelson Wallace B.
Published: May 2005

Background

Similarities between naturally occurring sleep and general anesthesia suggest that the two states may interact physiologically. The authors have previously demonstrated that sleep deprivation potentiates anesthetic-induced loss of righting reflex (LORR) in rats. One possible mediator for this effect is adenosine, which accumulates in the brains of sleep-deprived animals and reduces anesthetic requirements. The authors tested in rats the hypothesis that potentiating effects of sleep deprivation on LORR can be altered by adenosine A1 and A2a receptor antagonists.

Methods

Five experiments were conducted. In each, rats underwent four trials, consisting of a 24-h period of either sleep deprivation or ad libitum activity followed by administration of a fixed dose of an adenosine antagonist or vehicle. Rats were then given isoflurane, and the time to LORR and recovery were measured. Each experiment tested a specific dose of an A1 receptor antagonist (8-cyclopentyltheophylline given via microinjection into the basal forebrain), an A2a receptor antagonist (ZM241385 via intraperitoneal administration), or both. In each experiment, all rats received all combinations of activity and drug/vehicle, separated by 5-7 days.

Results

In rested rats, neither antagonist altered the time to LORR. In sleep-deprived rats, both ZM241385 and 8-cyclopentyltheophylline prolonged the time to LORR and shortened recovery in a dose-dependent manner. Prolongation also occurred when subtherapeutic doses of both agents were coadministered.

Conclusion

Both antagonists partially reversed the effect of sleep deprivation on anesthetic action. This result implies that deprivation-induced changes in adenosine receptor activity can alter LORR. Neither antagonist completely reversed this effect, suggesting possible non-adenosine-mediated effects of sleep deprivation.
Droperidol Inhibits Intracellular Ca2+, Myofilament Ca2+Sensitivity, and Contraction in Rat Ventricular Myocytes
Authors: Shiga Toshiya , Yong Sandro , Carino Joseph , Murray Paul A. , Damron Derek S.
Published: May 2005

Background

Droperidol has recently been associated with cardiac arrhythmias and sudden cardiac death. Changes in action potential duration seem to be the cause of the arrhythmic behavior, which can lead to alterations in intracellular free Ca concentration ([Ca]i). Because [Ca]i and myofilament Ca sensitivity are key regulators of myocardial contractility, the authors' objective was to identify whether droperidol alters [Ca]i or myofilament Ca sensitivity in rat ventricular myocytes and to identify the cellular mechanisms responsible for these effects.

Methods

Freshly isolated rat ventricular myocytes were obtained from adult rat hearts. Myocyte shortening, [Ca]i, nitric oxide production, intracellular pH, and action potentials were monitored in cardiomyocytes exposed to droperidol. Langendorff perfused hearts were used to assess overall cardiac function.

Results

Droperidol (0.03-1 mum) caused concentration-dependent decreases in peak [Ca]i and shortening. Droperidol inhibited 35 mm KCl-induced increase in [Ca]i, with little direct effect on sarcoplasmic reticulum Ca stores. Droperidol had no effect on action potential duration but caused a rightward shift in the concentration-response curve to extracellular Ca for shortening, with no concomitant effect on peak [Ca]i. Droperidol decreased pHi and increased nitric oxide production. Droperidol exerted a negative inotropic effect in Langendorff perfused hearts.

Conclusion

These data demonstrate that droperidol decreases cardiomyocyte function, which is mediated by a decrease in [Ca]i and a decrease in myofilament Ca sensitivity. The decrease in [Ca]i is mediated by decreased sarcolemmal Ca influx. The decrease in myofilament Ca sensitivity is likely mediated by a decrease in pHi and an increase in nitric oxide production.
Ketamine Preconditions Isolated Human Right Atrial Myocardium
Authors: Hanouz Jean-Luc , Zhu Lan , Persehaye Emmanuel , Massetti Massimo , Babatasi Gerard , Khayat André , Ducouret Pierre , Plaud Benoit , Gérard Jean-Louis
Published: May 2005

Background

The authors examined the effect of ketamine and its S(+) isomer on isolated human myocardium submitted to hypoxia-reoxygenation in vitro.

Methods

The authors studied isometric contraction of human right atrial trabeculae suspended in an oxygenated Tyrode's modified solution at 34 degrees C. Ten minutes before a 30-min hypoxic period followed by a 60-min reoxygenation, muscles were exposed for 15 min to racemic ketamine and its S(+) isomer at 10, 10, and 10 m alone or in the presence of 8.10 m 5-hydroxydecanoate, 10 m HMR 1098 (sarcolemmal adenosine triphosphate-sensitive potassium channel antagonist), 10 m phentolamine (alpha-adrenoceptor antagonist), and 10 m propranolol (beta-adrenoceptor antagonist). Force of contraction at the end of the 60-min reoxygenation period was compared between groups (mean +/- SD).

Results

Ketamine (10 m: 85 +/- 4%; 10 m: 95 +/- 10%; 10 m: 94 +/- 14% of baseline) and S(+)-ketamine (10-6 m: 85 +/- 4%; 10 m: 91 +/- 16%; 10 m: 93 +/- 14% of baseline) enhanced recovery of force of contraction at the end of the reoxygenation period as compared with the control group (47 +/- 10% of baseline; P < 0.001). Ketamine-induced preconditioning at 10 m was inhibited by 5-hydroxydecanoate (60 +/- 16%; P < 0.001), HMR 1098 (60 +/- 14%; P < 0.001), phentolamine (56 +/- 12%; P < 0.001), and propranolol (60 +/- 7%; P < 0.001).

Conclusions

In vitro, ketamine preconditions isolated human myocardium, at least in part, via activation of adenosine triphosphate-sensitive potassium channels and stimulation of alpha- and beta-adrenergic receptors.
Epidural Administration of Neostigmine and Clonidine to Induce Labor Analgesia
Authors: Roelants Fabienne , Lavand'homme Patricia M. , Mercier-Fuzier Valérie
Published: May 2005

Background

Epidural clonidine produces analgesia without motor impairment, and is associated with a local anesthetic-sparing effect during labor. The authors have recently demonstrated that epidural neostigmine initiates selective labor analgesia devoid of adverse effects. Both drugs possess common analgesic mechanisms mediated through spinal acetylcholine release. This study evaluates their epidural combination in parturients.

Methods

At the beginning of labor, parturients were randomly allocated to one of five groups to receive one of the following after a test dose: 150 microg epidural clonidine, 750 microg neostigmine, or 75 microg clonidine combined with 250, 500, or 750 microg neostigmine. A pain score (visual analog scale, 0-100) was recorded before administration and at regular intervals until request for a supplemental injection. Subsequent analgesia was provided by continuous epidural infusion of ropivacaine.

Results

Parturients did not differ regarding demographic data and initial pain score. Clonidine 150 microg , neostigmine 750 microg , and 75 microg clonidine plus 250 microg neostigmine produced ineffective and short-lasting effects. Clonidine 75 microg plus 500 microg neostigmine and 75 microg clonidine plus 750 microg neostigmine presented comparable durations of 90 +/- 32 and 108 +/- 38 min (mean +/- SD), respectively, and final analgesic efficacies, with 72.2% and 84%, respectively, of the parturients reporting a visual analog scale score of less than 30 out of 100 after 30 min. Ropivacaine use was significantly reduced in all clonidine groups (average, 9.5 mg/h) in comparison with neostigmine alone (17 +/- 3 mg/h). No adverse effects were observed for 75 mug clonidine combined with any dose of neostigmine while maternal sedation (20%) and hypotension (33%) occurred with 150 microg clonidine alone.

Conclusions

Epidural clonidine, 75 microg , with 750 microg neostigmine is an effective combination to initiate selective labor analgesia without adverse effects. Clonidine use further reduces local anesthetic consumption throughout the course of labor.