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PubMed2004

Finding extraterrestrial sites for thermophiles.

Virtually our entire knowledge of the universe comes from two sorts of measurement of the electromagnetic radiation from the stars and galaxies within it; either their flux through relatively wide bandpasses (photometry), or measurements of the shape and wavelength of relatively narrow lines via spectroscopy. These techniques are now being used to discover planets outside our solar system, and perhaps in the next 10 years will begin to characterize them. If a serious search is to be made for extraterrestrial thermophiles, we need predictions for the effects of thermophiles on their host planets that are observable with these techniques. In this paper I shall outline what sorts of observation are likely to be used in the next 15 years for extra-solar planet work. All of the journal articles quoted here can be found through http://adsabs.harvard.edu/abstract_service.html, and often also accessed as preprints at http://uk.arxiv.org/form/astro%20ph?MULTI=form%20+/-%20interface.

Astronomical Phenomena↗
PubMed1994

Effect of recombinant human growth hormone on cellular sodium metabolism.

1. The effect of treatment with recombinant human growth hormone on urinary sodium excretion, total body water, the renin-angiotensin system and erythrocyte sodium metabolism was investigated in 16 adults with growth hormone deficiency. 2. Total body water was determined by isotopic dilution, and erythrocyte electrolyte contents were analysed using flame photometry. The rate of sodium influx and the efflux rate constant of sodium were calculated from values of 22Na in erythrocytes in vitro. 3. One week of treatment with recombinant human growth hormone caused a decrease in urinary sodium excretion in 9/10 patients and an increase in erythrocyte sodium content. Total body water, plasma renin activity, angiotensin II concentration and transmembrane sodium transport were unaltered. 4. Six months of treatment with recombinant human growth hormone caused significant increases in total body water, erythrocyte sodium content and sodium transmembrane influx. Plasma renin activity tended to increase, whereas blood pressure and serum sodium and potassium concentrations remained unchanged. After 6 months on recombinant human growth hormone total body water showed a significant negative correlation with plasma renin activity. 5. The enhanced erythrocyte sodium transport, if this reflects what happens in the renal tubular cell, combined with a decrease in urinary sodium excretion, during treatment with recombinant human growth hormone could indicate an increase in tubular sodium reabsorption induced by the hormone. An increased plasma renin activity associated with the lack of blood pressure rise would reinforce sodium and water retention.

Adult↗
PubMed1999

Effects of bupivacaine on human erythrocytes submitted to stress and evidence for an interaction between bupivacaine and flumazenil.

AIMS: To examine the effects of bupivacaine on erythrocytes submitted to an oxidative stress (AAPH) and to provide evidence for an in vitro interaction between bupivacaine and flumazenil. METHODS: Human erythrocytes were studied with or without AAPH in the presence of different concentrations of bupivacaine (0.15, 0.3, 0.9 and 1.8 mmol l-1 ), or flumazenil (0.16 mmol l-1 ) and with the association of flumazenil and two doses of bupivacaine (0.15 and 0.3 mmol l-1 ). Potassium efflux was measured by flame photometry at T0, and every 30 min for 2 h. RESULTS: In the absence of AAPH, extracellular potassium remained unchanged. Oxidative stress induced a significant increase in extracellular potassium, which was not modified by incubation with flumazenil. Bupivacaine significantly lowered the increase in extracellular potassium in a dose-related fashion. The association with flumazenil blunted the effects of bupivacaine. Discussion In this model, bupivacaine proved effective in protecting erythrocytes against oxidative stress. Flumazenil interacted with bupivacaine and blunted its protective effects.

Anesthetics, Local↗
PubMed2002

Airway surface liquid recovered by lavage with perfluorocarbon liquid in cats.

BACKGROUND: Airway surface liquid (ASL) is difficult to sample. Lavage with an immiscible perfluorocarbon (PFC) liquid to recover ASL was evaluated in cats. MATERIALS AND METHODS: Six wild-type cats underwent bronchoscopic lavage with a PFC (perfluorohexane), with the bronchoscope wedged in the feline equivalent of the right lower lobe. Two cats (control animals) were lavaged with a saline vehicle only. Four procedures were performed on each animal at 2-3-week intervals. Ionic composition of ASL was determined by flame photometry. RESULTS: Cats lavaged with PFC showed significantly more acute respiratory distress than those lavaged with saline (respiratory rate following procedure: PFC, 47 +/- 5 min-1 vs. saline, 27 +/- 2 min-1, P < 0.05; O2 saturation: PFC 80 +/- 1% vs. saline, 91 +/- 1%, P < 0.01). The PFC group also had clinical evidence of chronic respiratory compromise (mean respiratory rate before next anaesthetic; PFC, 37 +/- 2 min-1 vs. saline, 20 +/- 3 min-1, P < 0.01). The PFC-lavaged lungs demonstrated persistent radiographic changes and histological evidence of small airways obstruction with distal alveolar damage. Six PFC lavages yielded ASL samples (> 100 microL) which were sufficient for analysis. Mean (+/- SEM) ionic concentrations in these samples were Na+ 157.4 +/- 14.5 mmol L-1, Cl- 150.5 +/- 16.8 mmol L-1 and K+ 10.1 +/- 1.7 mmol L-1. CONCLUSIONS: Perfluorocarbon lavage can be used to collect unmodified ASL from the distal lung. However, repeated lavage with perfluorohexane was associated with significant pathological changes in this study.

Animals↗
PubMed2001

Elevation of intracellular calcium levels contributes to the inhibition of nitric oxide production by atrial natriuretic peptide.

Atrial natriuretic peptide (ANP) attenuates LPS-induced inducible nitric oxide synthase (iNOS) expression in murine macrophages by destabilizing iNOS mRNA. Because elevated intracellular free Ca2+ levels [Ca2+]i reduce iNOS mRNA stability, the aim of the present study was to determine whether inhibition of iNOS by ANP is due to alterations in intracellular calcium. As determined by fluorescence photometry, ANP (10(-7) and 10(-6) mol/L) was shown to elevate intracellular calcium levels in bone marrow-derived macrophages. This effect seemed to be mediated via the guanylate cyclase-coupled A receptor, because dibutyryl-cGMP mimicked and the A-receptor antagonist HS-142-1 partially abrogated the effect of ANP. Because the Ca2+ increase was also observed in Ca2+-free buffer, it is suggested that the liberation of intracellular calcium pools contributes to the elevation of [Ca2+]i by ANP. The B-receptor ligand C-type natriuretic peptide (CNP), which does not alter iNOS expression, had no effect on [Ca2+]i. The Ca2+-ionophore 4-Br-A23187 and thapsigargin, a compound known to liberate Ca2+ from intracellular stores, were further demonstrated to reduce LPS-induced NO production in macrophages (Griess assay), confirming a functional link for elevated [Ca2+]i and iNOS inhibition. These effects were abrogated by coincubation with extra- as well as intracellular Ca2+ chelators (EGTA, 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA)). The inhibitory effect of ANP on NO production was also abrogated by Ca2+ chelation. These findings support a causal relationship between reduced iNOS induction and elevation of [Ca2+]i. Taken together, the data indicate that intracellular Ca2+ elevation by ANP is involved in the inhibition of LPS-induced nitric oxide production in macrophages.

Aniline Compounds↗
PubMed1999

A paper which changed clinical practice (slowly). Jacob Holler on potassium deficiency in diabetic acidosis (1946).

It is often said that the introduction of insulin into clinical medicine made a 'dramatic' difference to the mortality resulting from diabetic coma. This is true in the sense that before 1922 it was almost uniformly fatal, but until the 1950s the mortality in many large hospitals was as high as 30-50%. Often autopsy did not establish a cause of death. Many may have been a result of hypokalaemia, a complication which was not recognized until 1946; in that year in the Journal of the American Medical Association, Jacob Holler described a patient who developed respiratory paralysis 12h into treatment that, after several hours in an iron lung, was cured by potassium infusion. In the 5 years after Holler's paper there were many reports of deaths resulting from hypokalaemia, as well as several 'near misses', but clinicians were extremely cautious about early replacement probably, as an editorialist in The Lancet suggested, because 'the frightening effects of intravenous injections of potassium made clinicians reluctant to believe in a lack of potassium as a cause of trouble, except in very rare conditions such as familial periodic paralysis'. It had been known since 1923 that insulin lowered serum potassium, but this was not of great interest because the symptoms of hypokalaemia were not known. Also, potassium was not an electrolyte with which clinicians were familiar. Until the introduction of flame photometry in 1950, it was only measured in research studies as chemical methods took several hours to complete.

Diabetic Coma↗
PubMed2002

Transient rise in intracellular calcium produces a long-lasting increase in plasma membrane calcium pump activity in rat sensory neurons.

The plasma membrane Ca2+ ATPase (PMCA) plays a major role in clearing Ca2+ from the neuronal cytoplasm. Calmodulin stimulates PMCA activity and for some isoforms this activation persists following clearance of Ca2+ owing to the slow dissociation of calmodulin. We tested the hypothesis that PMCA-mediated Ca2+ efflux from rat dorsal root ganglion (DRG) neurons in culture would remain stimulated following increases in intracellular Ca2+ concentration ([Ca2+]i). PMCA-mediated Ca2+ extrusion was recorded following brief trains of action potentials using indo-1-based photometry in the presence of cyclopiazonic acid. A priming stimulus that increased [Ca2+]i to 506 +/- 28 nm (>15 min) increased the rate constant for [Ca2+]i recovery by 47 +/- 3%. Ca2+ clearance from subsequent test stimuli remained accelerated for up to an hour despite removal of the priming stimulus and a return to basal [Ca2+]i. The acceleration depended on the magnitude and duration of the priming [Ca2+]i increase, but was independent of the source of Ca2+. Increases in [Ca2+]i evoked by prolonged depolarization, sustained trains of action potentials or activation of vanilloid receptors all accelerated Ca2+ efflux. We conclude that PMCA-mediated Ca2+ efflux in DRG neurons is a dynamic process in which intense stimuli prime the pump for the next Ca2+ challenge.

Action Potentials↗
PubMed2003

A nephrological program in Benin and Togo (West Africa).

BACKGROUND: Nephrological programs are scarce in Benin and Togo, which are two small developing countries located in West Africa. This article describes a voluntary-based nephrological program that has recently been established in one hospital in north Benin and in another in south Togo. METHODS: The program included: (1) care of patients with a renal disease; (2) improvement of urinalysis; (3) introduction of serum Na+ and K+ measurements; and (4) screening of renal diseases. This was carried from the records of patients with serum creatinine >/=2.0 mg/dL and of patients with a >/=+++ albuminuria, and the distribution to doctors of a questionnaire. RESULTS: (1) Renal patients were seen on each visit at both hospitals; most had advanced renal failure or nephrotic syndrome. However, due to the lack of major diagnostic and therapeutic facilities, the management of such patients was often difficult. (2) Urinalysis was improved through the introduction of dipsticks for the evaluation of the 10 parameters, the introduction of phase contrast microscopy, and the permanent education of two laboratory technicians. (3) The introduction of flame photometry for the measurement of serum Na+ and K+ was unsuccessful probably due to the poor quality of water and/or gas. (4) In a year, patients in the Benin hospital who had serum creatinine values >/=2.0 mg/dL represented about 3.3% and patients with >/=+++ albuminuria represented 1.0% of all admissions. The questionnaire was answered by seven physicians working in three different institutions in Benin and in one in Togo. It revealed that basic diagnostic and therapeutic facilities, such as electrolyte measurement, urine culture, renal biopsy, and dialysis are either lacking or are available only for the few patients who can afford to pay. CONCLUSIONS: Severe renal diseases are found frequently in patients of Benin and Togo. However, due to the lack of money and basic diagnostic and therapeutic facilities, these patients cannot be properly managed.

Benin↗
PubMedDate not supplied

Improved alanine aminotransferase assay using the microtiter plate.

New procedures and new devices have been developed to improve the alanine aminotransferase (ALT) assay by using microtiter plates with 96 wells. Sera for ALT determination and reagents are distributed with a computer-controlled multiple syringe for simultaneous filling of the 96 wells. The volumes simultaneously distributed by this new multiple syringe show very little variation. The coefficient of variation (CV) is 0.6 percent (n = 96). Repeated filling of the wells with this syringe results in good reproducibility of distributed volumes (CV = 0.5%, n = 10). The temperature of sera, reagents, and mixtures, even during photometry, is actively regulated (down or up) to 25 degrees C in special chambers. Thus, the temperature varies minimally +/- 0.05 degrees C. ALT values in the low normal range as well as the high pathologic range show little variation (CV less than 2.3%) in aliquots of the same sample simultaneously or subsequently examined by the new procedure and with new devices. There is good correlation between the improved method using microtiter plates and the conventional methods (r greater than 0.9900, ALT values from 1-154 U/L). False-low and false-high values are excluded by computerized evaluation of many single determinations during the kinetic reactions in each sample. The new method is precise as well as simple, saves time, and may become important for the determination of other serum constituents on the basis of kinetics.

Alanine Transaminase↗
PubMed2002

Functional properties of EGFP-tagged skeletal muscle calcium-release channel (ryanodine receptor) expressed in COS-7 cells: sensitivity to caffeine and 4-chloro-m-cresol.

We constructed and expressed in COS-7 cells, three E-green fluorescent protein (EGFP) tagged recombinant skeletal muscle ryanodine receptors (RYR). EGFP was tagged to (i) the NH2-terminus (nEGFP-RYR(FL)) and to (ii) the COOH-terminus (cRYR(FL)-EGFP) of the full length RYR; we also tagged the EGFP to (iii) the NH2-terminus of a truncated version of the RYR (nEGFP-RYR(Bhat)) lacking the bulk of the protein. The fluorescent pattern EGFP with all three constructs colocalize with that of an endoplasmic reticulum (ER) membrane tracker fluorescent dye, indicating that the RYR constructs are targeted to ER membranes. Our results show that: (i) COOH-terminal tagging abolishes the sensitivity of the RYR to caffeine, whereas the presence of EGFP at the NH2-terminus does not affect caffeine sensitivity and (ii) 4-Cl-m-cresol sensitivity is lost both with the truncated nEGFP-RYR(Bhat) and the nEGFP-RYR(FL), while COOH-terminal tagging does not affect sensitivity to 4-chloro-m-cresol. The dose-response curves of caffeine-induced calcium release of nEGFP-RYR(FL) differ from those of the truncated nEGFP-RYR(Bhat). Maximal calcium release was approached at 10 mM caffeine with the nEGFP-RYR(FL), while cells expressing the nEGFP-RYR(Bhat) construct displayed a bell shaped curve and the maximal concentration for caffeine-induced calcium release was 5 mM. Equilibrium [3H]-ryanodine binding confirmed the calcium photometry data. Our results demonstrate that EGFP tagging modifies the pharmacological properties of RYR, and suggest that 4-chloro-m-cresol and caffeine act through different mechanisms and probably interact with different sites on the RYR calcium release channel.

Animals↗
PubMed2003

The radial forearm flap as a carrier for the osteocutaneous fibula graft in mandibular reconstruction.

According to the concept of a free flap carrier we transferred an osteocutaneous fibula graft after microanastomosis to a pedicled radial forearm flap for reconstruction of the lower face in a patient with a total occlusion of the left and a subtotal occlusion of the right common carotid artery. The fibula was osteotomized in three segments to form the new mandible, and the skin paddle was placed extraorally. An external fixation device was connected to the radial bone, and a halo frame was fixed to the skull, and the forearm was thus stabilized rigidly in a suitable position. After 2 weeks, serial occlusion of the pedicle was begun twice daily. Blood flow and haemoglobin oxygenation of the skin paddle were measured by laser Doppler flowmetry and photometry. At the 14th day of ischaemic preconditioning, the flap could tolerate 3h of occlusion. Then the carrier vessels and the forearm flap were excised. The flap survived completely based on neovascularization from the recipient site.

Bone Transplantation↗
PubMed1989

The effects of glibenclamide and its non-sulfonylurea analogue HB 699 on the sodium content of rat pancreatic islets.

Sodium contents were determined in rat pancreatic islets using integrating flame photometry. Whereas the sodium content decreased in the presence of glucose, it increased when 0.1-100 mumol/l glibenclamide was added to a medium containing 3 mmol/l glucose. The complexity of the glibenclamide action became evident with its reversal after removal of extracellular Ca2+ and the observation that the sulfonylurea counteracted the increase of sodium obtained after removal of K+. The effects of glibenclamide were mimicked by 1 mmol/l of its non-sulfonylurea analogue HB 699 with the exception that the latter compound being without suppressive action on the sodium content in medium deprived of Ca2+. Also exposure to 1 mmol/l sulfadiazine resulted in a Ca2+-dependent increase of sodium. The results suggest a role for sodium in amplifying the secretory response to the increased entry of Ca2+ obtained with the depolarisation of the beta-cells with glibenclamide or HB 699.

Animals↗
PubMed2000

Fecal bacterial activity in symptomatic carbohydrate malabsorption: effect on the fecal short-chain fatty acid ratio.

BACKGROUND: It is still not clear why only some patients with carbohydrate malabsorption experience symptoms. In a previous study on healthy fructose malabsorbers an increased degradation of fructose in anaerobic fecal cultures from symptomatic malabsorbers was found, indicating increased bacterial activity. In the present study, the same investigation was repeated in patients with nonspecific abdominal complaints and fructose malabsorption. Moreover fecal short-chain fatty acids (SCFA), products of colonic bacterial fermentation of carbohydrates were measured. PATIENTS AND METHODS: A standard quantity of fructose (500 mg) was added to anaerobic fecal cultures from 25 patients (nine men, 16 women; median of age 53 years, range 36-69 years). The fructose degradation rate was assessed using photometry, and interpreted as representing bacterial activity in the colon. In 14 of the patients, SCFA levels were also measured using chromatography on a capillary column. RESULTS: 10 of the 25 patients had a history of symptoms after ingesting fructose-containing foods, and also showed symptoms during the test; 6 patients had symptoms either in their history or during the test; and the remaining 9 were free of symptoms. There were no differences in the H2 increase. The fructose degradation rate was higher in symptomatic malabsorbers (255 mg vs. 217 mg), but the difference was not significant. However, there was a strong inverse correlation between this bacterial activity and the acetate level, with r = -0.822 (P = 0.000) and r = -0.868 (P = 0.000) in the rank correlation. The correlation for propionate was r = 0.479 (P = 0.083), and that for butyrate was r = 0.599 (P = 0.024). CONCLUSIONS: This study failed to confirm a significant correlation between fecal bacterial activity and the occurrence of symptoms in patients with fructose malabsorption. However, the interesting correlation with the SCFA raises questions regarding possible connections between colonic bacteria, carbohydrate malabsorption, and the beneficial effect of this pattern of SCFA in several colonic diseases.

Adult↗
PubMed2004

[Heparin Surface-Modified Poly(methylmethacrylate) and Foldable Hydrophobic Acrylic Intraocular Lenses in Cataract Patients with Acquired Immune Deficiency Syndrome and CMV-Retinitis].

BACKGROUND: In HIV-positive patients with necrotising retinitis, well-tolerated lens material as well as minimal invasive surgery to avoid postoperative complications are imperative. Heparin surface-modified PMMA-IOLs as well as acrylic IOLs are associated with less postoperative inflammation than conventional intraocular lenses. METHODS: In this randomised prospective clinical trial 18 patients received 7 HSM-IOLs through a self-sealing scleral tunnel and 11 foldable Acrysof-IOLs through a self-sealing limbal tunnel incision by the same surgeon. 7 of the 18 eyes were silicone oil-filled before cataract surgery, one eye received oil after the IOL implantation. Visual acuity, intraocular pressure, contrast sensitivity, intraocular inflammation and posterior capsule opacification were assessed. The follow-up period was 1 year. RESULTS: Eyes with Acrysof-IOLs were associated with lower, but not statistically significant, laser flare photometry values (photon counts/ms) than those with HSM-IOLs pre- (90.18 +/- 54.7 vs. 73.92 +/- 6.44) and 3 months post-surgery (69.06 +/- 8.27 vs. 55.03 +/- 7.75). 6 of the 7 eyes with HSM-IOL and 3 eyes of the Acrysof-group developed a dense posterior capsule opacification (PCO), 2 eyes had no and 6 eyes only a distinct PCO. YAG capsulotomy did not improve visual acuity in any case but retinal examination was again possible. Eyes with Acryl-IOL showed pre- and postoperatively a better visual acuity than eyes with HSM-IOL ("hand movement" - 0.4 vs. "no light perception" - 0.1 pre- and 0.05 - 0.6 vs. "no light perception" - 0.1 3 months postoperatively. Contrast sensitivity testing (Vistech method) could be performed in the PMMA-group preoperatively only in 1 eye (A1), in the Acryl-group in 2 eyes (A4, B4, C2, D2) and revealed postoperatively "no contrast vision" - A1, B2, C1 vs. "no contrast vision" - A2, B2, C3, D1, E1. The intraocular pressure was preoperatively 13.86 mm Hg (PMMA) vs. 14.82 mm Hg (Acrysof) and 14.4 mm Hg vs. 12.89 mm Hg 3 months post surgery. CONCLUSION: In the parameters we observed there was no statistical significant difference between heparin-surface modified (Pharmacia 811 C) and hydrophobic acrylic IOLs (Alcon Acrysof MA60BM) in patients with AIDS. As foldable Acrysof-IOLs can be implanted through a self-sealing bloodless tunnel incision and are associated with less posterior capsule opacification we prefer this IOL type in cataract surgery of AIDS patients.

AIDS-Related Opportunistic Infections↗
PubMed2004

Systematic investigation of different steroid precursors with respect to their effect on superoxide anion production by human neutrophil granulocytes.

Free radicals are involved in several pathological processes in living organisms, for example in athero- and oncogenesis. Some steroids are known to be effective antioxidants, while others do not play any such role. The aim of our study was to examine the antioxidant capability of different metabolites in the synthesis of steroid hormones. As a model, we chose human neutrophils producing superoxide anion, which is the source of many other radicals. Neutrophils were separated from healthy volunteers. Isolated cells were incubated with varying concentrations of steroid compounds and stimulated with N-formyl-Met-Leu-Phe. Superoxide anion production was determined by photometry. Neutrophils incubated with corticosterone and 18-hydroxy-deoxycorticosterone showed a significant reduction in superoxide production, whereas we found a significant enhancement in the presence of 11beta-hydroxyprogesterone. Furthermore, we observed a non-significant decreasing trend after incubation with cholesterol 3-sulphate and an increasing tendency using 11-hydroxyandrostenedione. We were also able to produce newer morphological and functional evidence of the role of myeloperoxidase enzyme in the steroidal antioxidant effect by electronic microscopy and use of sodium hypochlorite in our incubation model. Based on these results, we conclude that not only steroid end products but also their intermediate metabolites, most of which are also present in human plasma, partly influence free radical metabolism. Thus, this study provides further argument for the search for the molecular basis responsible for the antioxidant effect of steroid structures. This may lead to new opportunities for finding really efficient antioxidants, which might perhaps be used in a combined manner with other agents in the fight against certain life-threatening diseases.

Adult↗
PubMed2005

Improvement of conventional transcutaneous bilirubinometry results in term newborn infants.

This prospective study was performed to determine a way to improve conventional transcutaneous bilirubinometry results in healthy term newborn infants. In 118 infants during phototherapy (group A), and in 118 infants without phototherapy (group B), bilirubin determinations were done in duplicate using the Minolta AirShields Jaundice Meter type 101 (transcutaneous bilirubin index [TcB]), and the diazometric method on the Hitachi 717 Automated Analyzer (total reacting serum bilirubin [SeB]). In 112 infants (group C), bilirubin determinations were done in triplicate, using simple direct-reading photometry on the Moltronic Bilirubinometer (direct serum bilirubin [BiB]). A close correlation between TcB and SeB values was observed in group A ( r = 0.69; p < 0.001) and in group B ( r = 0.59; p < 0.001). The 95% confidence intervals of TcB readings corresponding to SeB were +/- 80.7 micromol/L in group A and +/- 76.9 micromol/L in group B, respectively. In group C, using a correctly calibrated BiB with adult sera containing bilirubin concentration in the range 271 to 344 micromol/L, the 95% confidence intervals of parallel TcB and BiB readings corresponding to SeB were +/- 28 micromol/L. Parallel determinations of the TcB and the BiB in healthy term newborn infants give results almost identical to those of bilirubin determination by the laboratory method.

Bilirubin↗
PubMed1994

[A possible risk for geriatric risk patients caused by intraoperative disorder of cerebral energy utilization?].

OBJECTIVE: This study was carried out on cerebrospinal fluid (CSF) to investigate the perioperative course of certain ischaemic markers, namely neurone-specific enolase (NSE), creatine kinase (CK-BB), hypoxanthine, and lactate in order to identify a disturbed cerebral energy utilisation which could be responsible for the development of temporary mental dysfunctions. Those dysfunctions are characterised by preserved memory content and perception, but the coordination and association of these functions are disturbed. Typical clinical signs are motor restlessness, disordered emotions, and symptoms of dementia. Little is known about the aetiology of those symptoms, but they are most likely due to various events, such as direct drug effects, the extent of surgical trauma, sensorial deprivation, and disturbed perfusion. METHODS: Eight orthopaedic patients (ASA III or IV) scheduled for removal of their total hip replacement were anaesthetised by catheter-spinal anaesthesia (CSA) for pain relief in combination with standardised, modified neuroleptanalgesia (NLA). At six defined times (15 hours preoperatively, immediately before and after surgery and 6, 24, and 36 hours postoperatively) CSF samples were drawn and the ischaemic markers were determined by means of radioimmunoassay (NSE), electrophoresis (CK-BB), photometry (lactate), and high-pressure liquid chromatography (hypoxanthine). The release of ischaemic markers into CSF correlates linear with the extent of ischaemic brain damage. RESULTS: Mean concentrations of the following ischaemic markers increased in all patients intraoperatively: NSE from 12.3 ng/ml to 13.4 ng/ml, hypoxanthine from 1.86 mumol/l to 3.73 mumol/l, and lactate from 1.4 mmol/l to 2.0 mmol/l respectively, all of which returned to normal within 36 hours. The CK-BB concentrations were all within normal values and not affected by the operation during this investigation. CONCLUSION: Although no clinical signs of temporary mental dysfunction have been observed, the results indicate that in CSF ischaemic markers temporarily undergo certain changes in their concentrations during the removal of total hip replacements in elderly patients. These changes are reason for assuming that risk patients may suffer a temporary disturbed cerebral energy utilisation intraoperatively, even if stable clinical and cardiovascular conditions prevail under anaesthesia. Such a temporary ischaemic penumbra might be responsible for the postoperative development of temporary mental dysfunctions.

Aged↗