Methoxyflurane and Nitrous Oxide as Obstetric Analgesics. II.—A Comparison by Self-administered Intermittent Inhalation

Methoxyflurane (0·35%) in air and nitrous oxide/oxygen (50%/50%) self-administered intermittently in the usual way have been compared as analgesics for labour. There were 25 patients in each group. Objective assessment by an anaesthetist showed that methoxyflurane is the more effective analgesic, and this was supported by the opinion of the multiparae. Nausea and vomiting were significantly less with methoxyflurane. Fifty per cent. nitrous oxide in oxygen given intermittently does not appear to be the best analgesic concentration. Nevertheless, since a considerable variation in sensitivity exists, it would probably be unwise to consider the introduction of higher concentrations for use by unsupervised midwives.This trial confirms the predictions made by us using a method for screening inhalational analgesics, in which methoxyflurane and nitrous oxide were given continuously.     

Methoxyflurane and Nitrous Oxide as Obstetric Analgesics. I.—A Comparison by Continuous Administration

Methoxyflurane and nitrous oxide have been compared as obstetric analgesics. The inhaled concentrations of these agents, given continuously, were adjusted by an anaesthetist to maintain each patient at the optimum state between reaction to pain and consciousness. Assessments were made continuously.Though the anaesthetist''s assessment showed no difference between the mean results, a greater proportion of the methoxyflurane patients were “satisfactory” for 90–100% of the time than of the nitrous oxide patients, particularly in regard to objective pain relief. The midwives'' opinion of those who had “complete” pain relief supported this. Nausea was significantly less among methoxyflurane patients, and vomiting during labour occurred only in patients who had nitrous oxide. It is concluded that nitrous oxide and methoxyflurane given in a continuously adjusted concentration are almost equally effective as obstetric analgesics, though there are certain features which favour methoxyflurane.     

Clinical Trials of Different Concentrations of Oxygen and Nitrous Oxide for Obstetric Analgesia: Report to the Medical Research Council of the Committee on Nitrous Oxide and Oxygen Analgesia in Midwifery

Trials have been organized by a Medical Research Council committee to assess the effectiveness and safety for analgesia in labour of oxygen and nitrous oxide mixtures in different proportions. In a preliminary trial concentrations of 50% and 60% v/v nitrous oxide were compared, but, as the replies of 409 mothers revealed little difference between the two, the results of administering either 50% or 70% nitrous oxide to 778 mothers were then compared. The data relating to normal labour, obtained on 501 of the mothers in this main trial, showed that the relief of pain given was much the same. There was a suggestion, however, that the higher concentration of nitrous oxide might be useful in abnormal labour. The proportion of mothers with normal deliveries who lost consciousness, though very small, was significantly higher with 70% nitrous oxide than with the lower concentration. Ninety-two per cent. of mothers found the gas and oxygen machine helpful, and midwives reported complete or good co-operation by 77% of those using it. It is concluded that the 50% oxygen and 50% nitrous oxide mixture can safely be used by unsupervised midwives.     

Acute renal dysfunction after cardiac surgery with cardiopulmonary bypass is associated with plasmatic IL6 increase

Background: Acute renal dysfunction (ARD) is common after cardiac surgery with cardiopulmonary bypass (CPB). CPB results in a sudden systemic inflammatory response. Systemic and local pro-inflammatory cytokines synthesis has been linked with sub-clinical renal injury, especially tubular lesions. Therefore, we sought to assess the systemic synthesis pro-inflammatory cytokines and its association with perioperative ARD after cardiac surgery with CPB. Methods: Sixty-two patients undergoing cardiac surgery with CPB were prospectively included. Four groups of patients were defined according to blood creatinine increase: no ARD (less than 25% increase), faint ARD (25–50% increase), moderate ARD (50–100% increase), severe ARD (more than 100% increase). Results: Within the 48 post-operative hours was ARD observed as no dysfunction (41.9%), faint (32.2%), moderate (16.1%), severe (9.6%). One patient had to undergo a dialysis. Pre-operative characteristics were homogenous between the four groups excepted the left ventricle ejection fraction. ARD was associated with a low urinary output with high sodium excretion fraction. Significant increase of IL-6 level occurred when patients underwent a severe ARD despite no significant differences for the CRP and TNF-α concentrations. Conclusion: Severe acute renal dysfunction after cardiac surgery with CPB is associated with a significant increased IL-6 systemic production.     

Does halothane anaesthesia decrease the metabolic and endocrine stress responses of newborn infants undergoing operation?

Concern about the side effects of various anaesthetic agents in newborn infants has led to the widespread use of anaesthesia with unsupplemented nitrous oxide and oxygen with muscle relaxants in such patients. To investigate the efficacy of such a regimen 36 neonates undergoing operations were randomised to two groups: one group received anaesthesia with nitrous oxide and curare alone and the other was additionally given halothane. Concentrations of metabolites and hormones were measured before and at the end of operation and at six, 12, and 24 hours after operation and the values compared between the two groups. Neonates given halothane anaesthesia showed decreased hormonal responses to operation, with significant differences between the two groups in the changes in adrenaline, noradrenaline, and cortisol concentrations and the ratio of insulin to glucagon concentration. Changes in blood concentrations of glucose and total ketone bodies and plasma concentrations of non-esterified fatty acids were also decreased in neonates receiving halothane anaesthesia. Neonates given anaesthesia with unsupplemented nitrous oxide showed significantly greater increases in the urinary ratio of 3-methylhistidine to creatinine concentration and their clinical condition was also more unstable during and after operation.Unless specifically contraindicated potent anaesthesia with halothane or other anaesthetic agents should be given to all neonates undergoing surgical operations as it decreases their stress responses and improves their clinical stability during and after operation.     

Acute Renal Failure and Open Heart Surgery

A retrospective study of 428 open heart operations showed the incidence of mild and severe renal failure to be 26% and 4·7% respectively. The mortality rate was 38% in the mild cases and 70% in the severe cases. Only half of the patients whose death was associated with renal failure showed macroscopic or microscopic renal lesions at necropsy. The patients who developed renal impairment had significantly higher mean preoperative blood urea (40 mg/100 ml) than the non-renal-failure cases (33 mg/100 ml). Periods of perfusion over 60 minutes, mean perfusion pressures below 80 mm Hg, and multiple valve replacement operations also increased the incidence of renal failure. There was no statistical correlation between the age of individual patients, the degree of cooling, and postoperative blood urea values. There was no evidence to suggest that frusemide or mannitol separately or together influenced the development of renal failure. Peritoneal dialysis was preferred for initial treatment of patients with severe renal failure, and haemodialysis was required only in special cases.     

Analgesic Nephropathy

Sixty-six patients were seen from January 1963 to December 1970 in whom a diagnosis of analgesic nephropathy was made. The ratio of women to men was 2·7:1 and women presented at an earlier age. Over 60% of patients had or developed urinary tract infection and over one-third presented with serum urea levels over 300 mg/100 ml. Hypertension was present in 60% of patients and almost 20% had a history of peptic ulcer; hysterectomy had been done in 35% of the women. Most patients improved initially but more than half of those followed up died within five years of presentation. A direct relation was found between prognosis and the degree of functional renal impairment at presentation. Hypertension appeared to have an adverse effect on prognosis but no relation of prognosis to papillary necrosis, infection, or surgical procedures was found.     

Clinical Significance of Dysuria in Women

During a community survey 22% of women were found to have had dysuria in the previous year and half had had dysuria at some time in their lives. Various measurements were made in a random sample of 282 of these women. The means and the variances of the systolic and diastolic blood pressures in women with a past history of dysuria tended to be higher than in women who gave no such history. There were no significant differences in the means of plasma urea, plasma creatinine, and renal concentrating power between women with and without a previous history of dysuria, but a significant impairment of renal concentrating power was found in an additional group of 30 women who dated the onset of their dysuria to childhood.These findings suggest that urinary tract infection in adult women does not usually lead to progressive impairment of kidney function, whereas infection in childhood is more often associated with kidney damage.     

Reproduction and fetal development in rats exposed to nitrous oxide

The effects of 24 hours of nitrous oxide exposure on reproductive indices and fetal development were examined in Sprague-Dawley rats. Four different experiments employing four concentrations of nitrous oxide--0.75%, 7.5%, 25% and 75%--established that the threshold of toxicity was greater than 25%. At 75% nitrous oxide there was a significant increase in early and late resorptions, and a consistent teratogenic effect (e.g., runts, ocular malformations, limb deformities). Neither the stress of shipping dams while pregnant nor the withholding of food during nitrous oxide exposure resulted in additional adverse effects. Exposure to 25% nitrous oxide was associated with increased deoxyuridine suppression values; however, adverse reproductive effects were not seen at this nitrous oxide concentration. The results of this and other studies which have examined the reproductive and teratogenic effects of nitrous oxide do not contraindicate its use in operating rooms nor, when necessary, as an anesthetic for pregnant surgical patients.     

Effects of gender on kidney function in magnesium-deficient rats

This study investigated the gender differences in the kidney function of magnesium (Mg)-deficient rats. Male and female rats were fed a control diet or a Mg-deficient diet for 21 d. Mg-deficient diet had no significant effect on kidney calcium (Ca) or phosphorus (P) concentration in male rats, while Ca and P concentrations in female rats were significantly higher in Mg-deficient rats than in the control rats. With regard to indicators of kidney function, no significant differences in creatinine clearance and serum urea nitrogen concentration were observed among the groups. Serum albumin concentrations were significantly lower in rats fed the Mg-deficient diet than in rats fed the control diet. In both sexes, urinary albumin excretion was significantly higher in rats fed the Mg-deficient diet than in rats fed the control diet. Gender differences had no significant influence on creatinine clearance, serum urea nitrogen concentration, serum albumin concentration and urinary albumin excretion. These results suggest that gender differences have no effect on kidney function in Mg-deficient rats under the condition used.     

Blood lead concentration,blood pressure,and renal function.

Blood lead concentrations were related to blood pressure and indicators of renal function in a clinical survey of 7735 middle aged men from 24 British towns. There was no overall evidence that blood lead concentrations were associated with systolic or diastolic blood pressure (r = +0.03 and +0.01, respectively). In the 74 men with a blood lead concentration of 1.8 mumol/l (37.3 micrograms/100 ml) or more there was some suggestion of increased hypertension, but this did not reach significance. Blood lead concentration did not have any relation with serum creatinine concentration. Moderate increases in blood lead concentration were associated with small increases in mean serum urate concentration and small decreases in mean serum urea concentration; these associations were both reduced when alcohol consumption was taken into account. There is no indication that exposure to lead at concentrations commonly encountered in British men is responsible for impaired renal function or increased blood pressure.     

Effects of dietary linoleic acid on blood pressure and renal function in subtotally nephrectomized rats

The effect of a high linoleic acid diet on blood pressure, renal function, and urinary prostaglandin excretion was studied in rats with decreased renal mass. Subtotally nephrectomized (5/6 nephrectomy) male rats received either a 15% linoleic acid (high linoleic acid, HLA) diet containing 20% safflower oil or a 0.28% linoleic acid (low linoleic acid, LLA) diet containing 20% coconut oil. Sham-operated rats were also placed on either HLA or LLA diet. The subtotal nephrectomized rats developed similar degrees of hypertension during the first 3 weeks after subtotal nephrectomy. However, 4 weeks after subtotal nephrectomy, the rats on HLA diet had significantly lower blood pressure than the rats on LLA diet [HLA 152 +/- 3 (mean +/- SE) mm Hg versus LLA 171 +/- 3 mm Hg]. This difference persisted until termination of the experiment at 7 weeks after subtotal nephrectomy (HLA 159 +/- 7 mm Hg versus LLA 192 +/- 6 mm Hg). The GFR measured 7 weeks after subtotal nephrectomy was significantly lower in both of the subtotally nephrectomized groups. However, the HLA subtotal nephrectomized rats had significantly higher GFR than the LLA-treated rats (HLA 0.23 +/- 0.05 ml/min 100 g versus LLA 0.12 +/- 0.02 ml/min/100 g, P less than 0.05). There was no difference in the GFR or blood pressure in the sham-operated rats treated with HLA or LLA diet. PGE2 excretion was lower in the two groups of subnephrectomized rats, but there was no difference between the HLA and LLA treated rats. Urinary 6-ketoPGF1 alpha was not decreased by subtotal nephrectomy and there was no difference between the dietary groups. However, TXB2 excretion was higher in the groups with subtotal nephrectomy, but there was no difference between the two dietary groups. In conclusion, the HLA diet attenuates the rise in blood pressure after subtotal nephrectomy in the rat and preserves renal function. There was no difference in urinary excretion of PGE2, 6-keto-PFG1 alpha, or thromboxane B2 between the two dietary groups.     

Residual effect of organic carbon as a tool for mitigating nitrogen oxides emissions in semi-arid climate

Residual effects of different fertilizers (mineral and organic) on the first pulses of carbon dioxide (CO₂), nitric oxide (NO), and nitrous oxide (N₂O) after rewetting dry soil with or without application of a mineral N fertilizer were studied in a laboratory experiment. Six months before this study was conducted the fields had received either manure + urea, manure, urea or no fertilizer. In the first phase the soil was rewetted with water simulating a summer shower (heavy rainfall in short time) and in the second phase with a urea solution simulating a mineral fertilization. There were not significant differences in trace gas emissions between earlier field treatments after soil was rewetted with water addition. However, after urea addition, plots that had received manure 6 months earlier showed smaller total emissions of N₂O and NO compared to plots that had only received urea. The residual effect of manure can play an important role in carbon poor soils under arid-semiarid climate in mitigating atmospheric pollutants such us NO and N₂O.     

The effect of propofol and fentanyl as compared with sevoflurane on postoperative vomiting in children after adenotonsillectomy

Postoperative vomiting (PV) after adenotonsillectomy in children is a common problem with an incidence as high as 40-80%. Only few studies in the recent literature compared the effect of different anesthetic techniques concerning PV in children. The aim of this study was to compare the incidence of PV in two groups of children who underwent two different general anesthesia techniques in order to determine what type of anesthetic technique is more related to less PV. The clinical trial included 50 children (physical status ASA I, 3-12 years old) divided into 2 groups and monitored for PV 24 hours following the surgery. Group one (G1) consisted of 25 children who underwent general anesthesia with gas mixture 60% nitrous oxide and 40% oxygen and anesthetic propofol, opioid fentanyl and muscle relaxant vecuronium intravenously and group two (G2) included 25 children to whom volatile anesthesia with sevoflurane in the same gas mixture was given. Demographic characteristics (gender, age, weight, history of motion sickness and earlier PV) as well as surgical data (length of surgery and anesthesia, intraoperative blood loss) were recorded. There were no significant differences considering demographic characteristics and surgical data between the investigated groups. The incidence of PV was relatively low 3 children (12%) in G1 group and 5 children (20%) in G2 group. Statistically there was no significant difference between the groups regarding the incidence of PV and both anesthetic techniques can be used equally safe regarded to PV.     

卡托普利与坎地沙坦对老年糖尿病肾病患者肾功能的影响

目的:研究卡托普利联合坎地沙坦对糖尿病肾病患者肾功能的影响及临床疗效。方法:选择2014年5月-2015年5月我院收治的糖尿病肾病患者90例,根据治疗方法不同分为观察组和对照组。对照组给予卡托普利治疗,观察组在对照组基础上加用坎地沙坦治疗。观察并比较两组患者的临床疗效以及治疗前后空腹血糖、血尿素氮、血肌酐、24 h尿蛋白等水平的变化情况。结果:观察组的治疗总有效率为93.3%,对照组的治疗总有效率为84.4%;观察组患者的临床疗效显著高于对照组,但差异并不具有统计学意义(P0.05)。与治疗前比较,两组患者治疗后的空腹血糖、血尿素氮、血肌酐及24 h尿蛋白水平均显著降低,差异具有统计学意义(P0.05);治疗后,观察组患者的空腹血糖、血尿素氮、血肌酐和24 h尿蛋白值均显著均明显低于对照组,差异均具有统计学意义(P0.05)。结论:卡托普利联合坎地沙坦治疗糖尿病肾病较单独采用卡托普利治疗能够更加有效的改善患者的临床症状,保护患者的肾功能,具有较好的临床疗效。     

A Comparison of the Long-Term Effects of Lanthanum Carbonate and Calcium Carbonate on the Course of Chronic Renal Failure in Rats with Adriamycin-Induced Nephropathy

Lanthanum carbonate (LA) is an effective phosphate binder. Previous study showed the phosphate-binding potency of LA was twice that of calcium carbonate (CA). No study in which LA and CA were given at an equivalent phosphate-binding potency to rats or humans with chronic renal failure for a long period has been reported to date. The objective of this study was to compare the phosphate level in serum and urine and suppression of renal deterioration during long-term LA and CA treatment when they were given at an equivalent phosphate-binding potency in rats with adriamycin (ADR)-induced nephropathy. Rats were divided into three groups: an untreated group (ADR group), a CA-treated (ADR-CA) group and a LA-treated (ADR-LA) group. The daily oral dose of LA was 1.0 g/kg/day and CA was 2.0 g/kg/day for 24 weeks. The serum phosphate was lower in the ADR-CA or ADR-LA group than in the ADR group and significantly lower in the ADR-CA group than in the ADR group at each point, but there were no significant differences between the ADR and ADR-LA groups. The serum phosphate was also lower in the ADR-CA group than in the ADR-LA group, and there was significant difference at week 8. The urinary phosphate was significantly lower in the ADR-CA group than in the ADR or ADR-LA group at each point. The urinary phosphate was also lower in the ADR-LA group than in the ADR group at each point, and significant difference at week 8. There were no significant differences in the serum creatinine or blood urea nitrogen among the three groups. In conclusion, this study indicated the phosphate-binding potency of LA isn’t twice as strong as CA, and neither LA nor CA suppressed the progression of chronic renal failure in the serum creatinine and blood urea nitrogen, compared to the untreated group.     

Zinc and Copper Concentrations in Human Preterm Milk

Zinc and copper are important trace elements in the nutrition of preterm infants. This study determined and compared the concentrations of zinc and copper in preterm milk of mothers receiving and not receiving zinc supplementation diets. The effects of maternal supplementation on the blood levels and anthropometric parameters were evaluated. Thirty-eight mothers and their preterm infants were enrolled in the study. Eighteen mothers were given a daily supplementation of 50 mg zinc, whereas the other 20 were not. Zinc and copper levels in milk were determined at 15-day intervals, as were blood zinc levels along with anthropometric parameters. Zinc and copper contents were determined by atomic absorption spectrophotometry. No significant differences were found between groups either for zinc values in maternal milk and infant blood or for anthropometric measurements. A pronounced decrease in copper levels was observed in mothers receiving supplemental zinc. Zinc supplementation given to mothers who were breastfeeding preterm infants had no significant effect on zinc secretion in milk.     

Nitrous oxide emissions from a gully mire in mid-Wales, UK, under simulated summer drought

Certain general circulation models predict that a doubling of atmospheric carbon dioxide concentrations will increase the frequency of summer drought in northern wetlands due to hotter, drier summers. There is currently much uncertainty as to how drought will affect emissions of the greenhouse gas, nitrous oxide, from wetlands. We have demonstrated that an eight centimetre drawdown of the water table in a gully mire does not significantly affect nitrous oxide emissions from this site. However, under a more extreme drought scenario carried out on peat monoliths, nitrous oxide emissions increased exponentially with a linear decrease in water table height. Drought caused a significant increase in nitrous oxide productionbelow the water table but most of the total increase could be attributed to increased emissionsabove the water table. Results from an acetylene block experiment suggested that increased emissions were caused by increased nitrous oxide production from denitrification, rather than by increased production from nitrification. In the laboratory study, drought severity had no effect on peatwater nitrate concentrations below the water table, however, increasing drought severity decreased ammonium concentrations.     

汞中毒患者尿中性粒细胞明胶酶脂质相关运载蛋白的含量及其意义

目的：检测汞中毒患者尿中性粒细胞明胶酶脂质相关运载蛋白（U－NGAL）的含量,探讨其在汞中毒早期肾损伤中的意义。方法：以24例我科收住院患者为汞中毒组、无汞接触史的15例健康成人为对照组,分别进行临床体检并测定尿－N－乙酰－D－葡萄糖苷酶（U－NAG）、24h尿蛋白定量（UPQ）、尿β2微球蛋白（U－β2－MG）、尿α1微球蛋白（U－α1－MG）、尿汞（U－Hg）、血汞（B－Hg）、血肌酐（Scr）、血尿素氮（BUN）,排除既往肾脏病史,ELISA法测定U－NGAL含量,并分析上述结果。结果：汞中毒组B－Hg、U－Hg、U－NAG、UPQ、U－β2－MG、U－α1－MG、U－NGAL与对照组相比均有统计学差异（P〈0．05）,传统指标Ser、BUN与对照组相比无统计学差异;U－α1－MG、U－β2－MG、U－NAG、UPQ、U－NGAL与B－Hg均有相关性,且相关系数逐渐递增。结论：长期汞接触可造成肾功能损害,U－α1－MG、U－β2－MG、U－NAG、UPQ、U－NGAL可作为汞中毒肾早期损害的敏感指标,且灵敏性依次递增;U－NGAL可能比U－NAG早出现。     

Increased salt sensitivity secondary to leptin resistance in SHHF rats is mediated by endothelin

A link between leptin resistance, obesity, and salt sensitivity has been suggested. SHHF/Mcc-fa ^cp rats (SHHF) were used to study the effect of gene dosage of a null mutation of the leptin receptor (cp) on salt sensitivity and response to a combined endothelin A and B receptor antagonist (bosentan). Obese (cp/cp), heterozygous (+/cp), and homozygous lean (+/+) male SHHF were fed a low salt diet (0.3% NaCl) for 7 days, followed by a high salt diet (8.0% NaCl) for 7 days. There were no significant differences in systolic blood pressure between genotypes on low salt. In response to high salt, cp/cp had significantly greater systolic pressure than +/cp and +/+. On high salt diet, cp/cp showed a significant increase in 24 h urinary endothelin excretion and increased renal expression of preproendothelin mRNA. There was no effect of high salt diet on renal excretion of nitric oxide (NOx) or on gene expression of endothelial, neuronal, or cytokine-induced nitric oxide synthase isoforms (eNOS, nNOS, iNOS, respectively). Treatment with bosentan prevented the high salt-induced increment in systolic blood pressure in cp/cp. This was associated with a doubling of renal NOx excretion, but without changes in eNOS, nNOS, or iNOS expression. Endothelin receptor antagonism did not normalize systolic pressure in any of the genotypes. Our studies indicate that obesity secondary to leptin resistance (cp/cp) results in increased salt sensitivity that is mediated by endothelin in the SHHF rat.