Reversible, tunable epigenetic silencing of TCF1 generates flexibility in the T cell memory decision

The immune system encodes information about the severity of a pathogenic threat in the quantity and type of memory cells it forms. This encoding emerges from lymphocyte decisions to maintain or lose self-renewal and memory potential during a challenge. By tracking CD8+ T cells at the single-cell and clonal lineage level using time-resolved transcriptomics, quantitative live imaging, and an acute infection model, we find that T cells will maintain or lose memory potential early after antigen recognition. However, following pathogen clearance, T cells may regain memory potential if initially lost. Mechanistically, this flexibility is implemented by a stochastic cis-epigenetic switch that tunably and reversibly silences the memory regulator, TCF1, in response to stimulation. Mathematical modeling shows how this flexibility allows memory T cell numbers to scale robustly with pathogen virulence and immune response magnitudes. We propose that flexibility and stochasticity in cellular decisions ensure optimal immune responses against diverse threats.

Early generation of a precursor CD8 T cell that can adapt to acute or chronic viral infection

Virus specific PD-1+ TCF-1+ TOX+ stem-like CD8+ T cells are essential for maintaining T cell responses during chronic infection and are also critical for PD-1 directed immunotherapy. In this study we have used the mouse model of chronic LCMV infection to examine when these virus specific stem-like CD8+ T cells are generated during the course of chronic infection and what is the role of antigen in maintaining the stem-like program. We found that these stem-like CD8+ T cells are generated early (day 5) during chronic infection and that antigen is essential for maintaining their stem-like program. This early generation of stem-like CD8+ T cells suggested that the fate commitment to this cell population was agnostic to the eventual outcome of infection and the immune system prepares a priori for a potential chronic infection. Indeed, we found that an identical virus specific stem-cell like CD8+ T cell population was also generated during acute LCMV infection but these cells were lost once the virus was cleared. To determine the fate of these early PD-1+TCF-1+TOX+ stem-like CD8+ T cells that are generated during both acute and chronic LCMV infection we set up two reciprocal adoptive transfer experiments. In the first experiment we transferred day 5 stem-like CD8+ T cells from chronically infected into acutely infected mice and examined their differentiation after viral clearance. We found that these early stem-like CD8+ T cells downregulated canonical markers of the chronic stem-like CD8+ T cells and expressed markers (CD127 and CD62L) associated with central memory CD8+ T cells. In the second experiment, we transferred day 5 stem-like cells from acutely infected mice into chronically infected mice and found that these CD8+ T cells could function like resource cells after transfer into a chronic environment by generating effector CD8+ T cells in both lymphoid and non-lymphoid tissues while also maintaining the number of stem-like CD8+ T cells. These findings provide insight into the generation and maintenance of virus specific stem-like CD8+ T cells that play a critical role in chronic viral infection. In particular, our study highlights the early generation of stem-like CD8+ T cells and their ability to adapt to either an acute or chronic infection. These findings are of broad significance since these novel stem-like CD8+ T cells play an important role in not only viral infections but also in cancer and autoimmunity.

NanoMEA: A Tool for High-Throughput, Electrophysiological Phenotyping of Patterned Excitable Cells

Matrix nanotopographical cues are known to regulate the structure and function of somatic cells derived from human pluripotent stem cell (hPSC) sources. High-throughput electrophysiological analysis of excitable cells derived from hPSCs is possible via multielectrode arrays (MEAs) but conventional MEA platforms use flat substrates and do not reproduce physiologically relevant tissue-specific architecture. To address this issue, we developed a high-throughput nanotopographically patterned multielectrode array (nanoMEA) by integrating conductive, ion-permeable, nanotopographic patterns with 48-well MEA plates, and investigated the effect of substrate-mediated cytoskeletal organization on hPSC-derived cardiomyocyte and neuronal function at scale. Using our nanoMEA platform, we found patterned hPSC-derived cardiac monolayers exhibit both enhanced structural organization and greater sensitivity to treatment with calcium blocking or conduction inhibiting compounds when subjected to high-throughput dose-response studies. Similarly, hPSC-derived neurons grown on nanoMEA substrates exhibit faster migration and neurite outgrowth speeds, greater colocalization of pre- and postsynaptic markers, and enhanced cell-cell communication only revealed through examination of data sets derived from multiple technical replicates. The presented data highlight the nanoMEA as a new tool to facilitate high-throughput, electrophysiological analysis of ordered cardiac and neuronal monolayers, which can have important implications for preclinical analysis of excitable cell function.

Rectal varices due to chronic inferior mesenteric vein thrombosis caused by external compression in a large hiatus hernia containing the pancreas

A 79-year-old woman presented with a large fresh rectal bleed. Computed tomography revealed that she had a large type IV hiatus hernia, which contained the stomach and pancreas. Compression of the inferior mesenteric vein and splenic vein had led to thrombosis within these vessels and retrograde flow within the inferior mesenteric vein. This had led to the formation of portosystemic rectal varices. Ectopic varices occasionally form in the rectum, often in the context of liver cirrhosis. At the time of writing, ours is the first reported case of portosystemic rectal varices formulated in response to obstruction of vessels within a hiatus hernia.

Data describing the swelling behavior and cytocompatibility of biodegradable polyelectrolyte hydrogels incorporating poly(L-lysine) for applications in cartilage tissue engineering

This data article presents data associated with the research article entitled "Evaluation of cell-laden polyelectrolyte hydrogels incorporating poly(L-lysine) for applications in cartilage tissue engineering" (Lam et al., 2016) [1]. Synthetic hydrogel composites fabricated using oligo(poly(ethylene glycol) fumarate) (OPF) macromers were utilized as vehicles for the incorporation of poly(L-lysine) (PLL) as well as the encapsulation of mesenchymal stem cells (MSCs). PLL-laden and PLL-free hydrogels were fabricated to characterize the main and interaction effects of OPF molecular weight, PLL molecular weight, and PLL loading density on the swelling and degradation of synthetic OPF hydrogels. Cells were then encapsulated within such hydrogels for in vitro culture and examined for viability, biochemical activity, and chondrogenic gene expression. These data, which are supplementary to the associated research article (Lam et al., 2016) [1], are presented here.

Evaluation of cell-laden polyelectrolyte hydrogels incorporating poly(L-Lysine) for applications in cartilage tissue engineering

To address the lack of reliable long-term solutions for cartilage injuries, strategies in tissue engineering are beginning to leverage developmental processes to spur tissue regeneration. This study focuses on the use of poly(L-lysine) (PLL), previously shown to up-regulate mesenchymal condensation during developmental skeletogenesis in vitro, as an early chondrogenic stimulant of mesenchymal stem cells (MSCs). We characterized the effect of PLL incorporation on the swelling and degradation of oligo(poly(ethylene) glycol) fumarate) (OPF)-based hydrogels as functions of PLL molecular weight and dosage. Furthermore, we investigated the effect of PLL incorporation on the chondrogenic gene expression of hydrogel-encapsulated MSCs. The incorporation of PLL resulted in early enhancements of type II collagen and aggrecan gene expression and type II/type I collagen expression ratios when compared to blank controls. The presentation of PLL to MSCs encapsulated in OPF hydrogels also enhanced N-cadherin gene expression under certain culture conditions, suggesting that PLL may induce the expression of condensation markers in synthetic hydrogel systems. In summary, PLL can function as an inductive factor that primes the cellular microenvironment for early chondrogenic gene expression but may require additional biochemical factors for the generation of fully functional chondrocytes.

Electrical control of the exciton-biexciton splitting in self-assembled InGaAs quantum dots

The authors demonstrate how lateral electric fields can be used to precisely control the exciton-biexciton splitting in InGaAs quantum dots. By defining split-gate electrodes on the sample surface, optical studies show how the exciton transition can be tuned into resonance with the biexciton by exploiting the characteristically dissimilar DC Stark shifts. The results are compared to model calculations of the relative energies of the exciton and biexciton, demonstrating that the tuning can be traced to a dominance of hole-hole repulsion in the presence of a lateral field. Cascaded decay of the exciton-biexciton system enables the generation of entangled photon pairs without the need to suppress the fine structure splitting of the exciton. Our results demonstrate how the exciton-biexciton system can be electrically controlled.

An atomically resolved study of InGaAs quantum dot layers grown with an indium flush step

In this cross-sectional scanning tunnelling microscopy study we investigate the indium flush method as a means to control the height of self-assembled InGaAs quantum dots and wetting layers. The results show that application of an indium flush step during growth results in flattened dots and a reduced wetting layer of which the height can be precisely controlled by varying the height of the first capping layer.

Optically probing spin and charge interactions in a tunable artificial molecule

We optically probe and electrically control a single artificial molecule containing a well defined number of electrons. Charge and spin dependent interdot quantum couplings are probed optically by adding a single electron-hole pair and detecting the emission from negatively charged exciton states. Coulomb- and Pauli-blockade effects are directly observed, and tunnel coupling and electrostatic charging energies are independently measured. The interdot quantum coupling is shown to be mediated by electron tunneling. Our results are in excellent accord with calculations that provide a complete picture of negative excitons and few-electron states in quantum dot molecules.

Direct observation of controlled coupling in an individual quantum dot molecule

We report the direct observation of quantum coupling in individual quantum dot molecules and its manipulation using static electric fields. A pronounced anticrossing of different excitonic transitions is observed as the electric field is tuned. A comparison of our experimental results with theory shows that the observed anticrossing occurs between excitons with predominant spatially direct and indirect character and reveals a field driven transition of the nature of the molecular ground state exciton wave function. Finally, the interdot quantum coupling strength is deduced optically and its dependence on the interdot separation is calculated.

Glutamine deprivation facilitates tumour necrosis factor induced bacterial translocation in Caco-2 cells by depletion of enterocyte fuel substrate

BACKGROUND AND AIMS

Factors that induce luminal bacteria to cross the intestinal epithelium following injury remain poorly defined. The aim of this study was to investigate the interaction between glutamine metabolism, energy supply, and inflammatory mediators in determining the translocation of non-pathogenic bacteria across cultured enterocytes.

METHODS

The effect of tumour necrosis factor alpha (TNF-alpha) on translocation of Escherichia coli C25 across Caco-2 epithelial monolayers was studied in the presence of products and inhibitors of glutamine metabolism. Simultaneous measurements of transepithelial electrical resistance (TEER) and flux of lucifer yellow were used to assess effects on the paracellular pathway. Lactate dehydrogenase release was used to monitor enterocyte integrity. Imaging of monolayers in these experimental conditions was undertaken with transmission electron microscopy.

RESULTS

Exposure to basolateral TNF-alpha (20 ng/ml) for six hours induced translocation of E coli across Caco-2 but only if accompanied by simultaneous glutamine depletion (p<0.01). Translocation was inhibited by addition of glutamine for two hours (p<0.01) but not by an isonitrogenous mixture of non-glutamine containing amino acids. Inhibition of glutamine conversion to alpha-ketoglutarate, but not blockade of glutathione or polyamine synthesis, also induced translocation in the presence of TNF-alpha. Manipulations that induced bacterial translocation were associated with a marked reduction in enterocyte ATP levels. No effect of these treatments on paracellular permeability or lactate dehydrogenase release was observed. Conditions in which translocation occurred were associated with the presence of bacteria within enterocyte vacuoles but not the paracellular space.

CONCLUSIONS

In inflammatory conditions, the availability of glutamine as an enterocyte fuel substrate is essential for the preservation of a functional barrier to microorganisms. In conditions of acute glutamine depletion, cytokine mediated bacterial translocation appears to be primarily a transcellular process.

Brain mediation of Anolis social dominance displays. II. Differential forebrain serotonin turnover, and effects of specific 5-HT receptor agonists

Serotonin (5-HT) functions are associated with social dominance status in diverse species, but to date the brain regions wherein 5-HT exerts such effects are uncertain. Here, we indexed 5-HT turnover in male Anolis carolinensis as the ratio of 5-HT to its metabolite, 5-hydroxy-indol-acetic acid, and also as the accumulation of the in vivo tracer 14C-alpha-methyl-tryptophan (14C-AMT). After patching one eye, displaying dominant animals increased both measures of 5-HT turnover in the forebrain hemisphere receiving display-evocative visual stimuli, compared to control, contralateral brain, whereas both 5-HT turnover indices were decreased when animals displayed submissively. In contrast, various non-displaying controls showed forebrain symmetry on both measures. Drugs that stimulate 5-HT(2C) receptors in mammals, and have 5-HT(2C)-like binding in A. carolinensis, evoked some elements of dominant display behaviors in non-dominant anole males and also activated dorsolateral basal ganglia as seen in non-medicated dominants when they display [Baxter et al., 2001]. Thus, acute changes in forebrain 5-HT output from baseline equilibrium, acting at 5-HT(2C)-like receptors, might effect some elements of the dominant vs. submissive male anoles' territorial displays. A mechanistic model of how this might occur is offered. Given similarities in 5-HT systems, forebrain functions, and territorial display routines, similar mechanisms might have similar functions in other amniotes, including primates.

Brain mediation of Anolis social dominance displays. I. Differential basal ganglia activation

Ritualistic displays of aggressive intent are important social signals, often obviating physically dangerous engagement. To date, however, brain regions mediating such behaviors are not established. Here we used male Anolis carolinensis together with an in vivo 14C-2-deoxyglucose method to determine patterns of brain activation during elicitation of this animal's dominance displays vs. other behaviors. By patching one eye regional brain activation in the hemisphere receiving display-evocative visual stimuli ('seeing' side) was compared to activity in the contralateral brain that did not see specific stimuli ('patched' side); this was quantitated as the ratio of seeing/patched activity for brain regions of interest. Lone males displaying dominantly to mirrors activated dorsolateral basal ganglia (BG) in the seeing, compared to the patched hemisphere; this was not seen in various non-displaying controls. Degree of dorsolateral BG activation also correlated with a measure of dominant display activity, but not with locomotion. In socially stable pairs, displaying dominants showed similar activation of dorsolateral BG, but deactivated ventromedial BG; non-dominant cagemates displaying submissively had the opposite pattern. When cohabiting peacefully without displaying, paired dominants' and subordinates' brain activity patterns were similar to each other. Thus, different BG subsystems seem involved in dominant vs. submissive display behaviors. Given similarities in both social displays and BG organization, homologous brain systems might have similar functions in members of other amniote classes, including primates.

Mammal-like striatal functions in Anolis. I. Distribution of serotonin receptor subtypes, and absence of striosome and matrix organization

Serotonin (5-HT) 5-HT(2A) and 5-HT(2C) receptors are thought to play important roles in the mammalian striatum. As basal ganglia functions in general are thought highly conserved among amniotes, we decided to use in situ autoradiographic methods to determine the occurrence and distribution of pharmacologically mammal-like 5-HT(2A) and 5-HT(2C) receptors in the lizard, Anolis carolinensis, with particular attention to the striatum. We also determined the distributions of 5-HT(1A), 5-HT(1B/D), 5 HT(3), and 5-HT(uptake) receptors for comparison. All 5-HT receptors examined showed pharmacological binding specificity, and forebrain binding density distributions that resembled those reported for mammals. Anolis 5 HT(2A/C) and 5-HT(1A) site distributions were similar in both in vivo and ex vivo binding experiments. 5-HT(2A & C) receptors occur in both high and low affinity states, the former having preferential affinity for (125)I-(+/-)-2,5-dimethoxy-4-iodo-amphetamine hydrochloride ((125)I-DOI). In mammals (125)I-DOI binding shows a patchy density distribution in the striatum, being more dense in striosomes than in surrounding matrix. There was no evidence of any such patchy density of (125)I-DOI binding in the anole striatum, however. As a further indication that anoles do not possess a striosome and matrix striatal organization, neither (3)H-naloxone binding nor histochemical staining for acetylcholinesterase activity (AChE) were patchy. AChE did show a band-like striatal distribution, however, similar to that seen in birds.

Mammal-like striatal functions in Anolis. II. Distribution of dopamine D(1) and D(2) receptors, and a laminar pattern of basal ganglia sub-systems

We used in situ autoradiographic ligand binding methods to determine the occurrence and distribution of dopamine D(1) and D(2) receptor sub-types in the anole lizard, Anolis carolinensis. Both were present and exhibited pharmacological specificity characteristics similar to those described for mammals. However, unlike in mammals where in the neostriatum [outside the nucleus accumbens/olfactory tubercle complex (NA/OT)] these receptors exhibit only slight dorsolateral (D(2) high, D(1) low) to ventromedial (D(1 )high, D(2) low) gradients that co mingle extensively, in the anole striatum outside the NA/OT there was a striking laminar pattern, with little if any overlap between D(2) (high in a dorsal band) and D(1) (high ventral to the D(2) band) distributions. As D(1) receptors are related to the direct and D(2) to the indirect basal ganglia (BG) subsystems in mammals, we also determined anole striatal distributions of pre-proenkephalin mRNA, a marker for striatal efferents to the indirect BG subsystem in mammals. Here, too, there was a striking laminar pattern, with pre-proenkephalin mRNA in a band similar to that seen for D(2) receptors. The crisp neuroanatomical separation between these classic BG subsystem markers in Anolis striatum make this species attractive for the study of such systems' functions during behavior.

Pathogenesis of cerebral edema after treatment of diabetic ketoacidosis

We studied the roles of acidosis, plasma osmolality, and organic osmolytes in the pathogenesis of cerebral edema in an animal model of diabetes mellitus. Normonatremic rats with streptozotocin-induced non-ketotic (NKD) and ketotic (DKA) diabetes were sacrificed before or after treatment with hypotonic saline and insulin. Brains were analyzed for water, electrolyte, and organic osmolyte content. Brain water decreased by 2% in untreated DKA and NKD despite a 12% increase in plasma osmolality due to hyperglycemia. After treatment of both NKD and DKA, brain water increased equivalently by 8%. The cerebral edema that occurred after treatment was associated with decreased brain sodium content and no change in total major brain organic osmolytes in both NKD and DKA. However, brain content of the individual osmolytes glutamine and taurine increased after treatment of DKA. In a separate study, brain water and solute content of rats with DKA were compared after treatment with either hypotonic or isotonic fluid. Animals treated with isotonic fluid had significantly less cerebral edema and higher brain sodium content than those treated with hypotonic fluid. In our studies, brain swelling after treatment of DKA and NKD was primarily due to a rapid reduction of plasma glucose and osmolality, and was not caused by sodium movement into the brain. Acidosis did not appear to play a major role in the pathogenesis of cerebral edema after treatment of DKA.

Depletion of glutathione from brain cells in hyponatremia

In response to hyponatremia, brain cells extrude electrolytes and organic osmolytes, thereby minimizing brain edema. We demonstrate that rat brain is depleted of the antioxidant glutathione in response to hyponatremia and that osmotically-induced loss of glutathione makes neuronal cells more susceptible to oxidative injury. Total glutathione content of brain tissue decreased from 6.80 +/- 0.14 mumol/g dry wt in normonatremic controls to 5.00 +/- 0.31 mumol/g dry wt after 72 hours of hyponatremia. Following slow correction of hyponatremia, brain glutathione content returned to control values (6.77 +/- 0.34 mumol/g dry wt). Brain content of taurine, a beta-amino acid with antioxidant properties, similarly decreased in hyponatremia (29.6 +/- 0.9 to 17.1 +/- 1.2 mumol/g dry wt), then increased with slow correction (24.8 +/- 1.3 mumol/g dry wt). Although taurine served as an osmolyte in rat heart, liver and brain, osmotically-induced changes in glutathione content were found only in brain. We also studied osmotically-induced changes in glutathione and taurine content in C6 glioma and SK-N-SH neuroblastoma cells. In both cell lines, adaptive decreases in glutathione and taurine content were found in response to lowering medium sodium concentration from 140 mM to 100 mM. The cell content of these solutes increased after returning to media containing 140 mM sodium. Following exposure of both cell lines to hypoosmolar media, there was no increase in media content of glutathione. This suggest that osmotic depletion of glutathione is not due to cellular efflux of intact glutathione. We questioned if osmotic depletion of glutathione and taurine renders brain cells more susceptible to oxidative stress. Incubation of SK-N-SH cells with 1.0 mM H2O2 for four hours induced greater cytolytic injury in cells adapted to hypoosmolar media than in isoosmolar controls. Hypoosmolar C6 glioma cells were not significantly more sensitive to cytolytic injury from H2O2 than were cells grown in isosmolar media. We conclude that hypoosmolality induces glutathione depletion in rat brain in vivo and in cultured brain cells in vitro. Osmotic depletion of this antioxidant renders SK-N-SH neuronal cells more susceptible to oxidative injury.

Continuous ambulatory peritoneal dialysis complicated by Aureobasidium pullulans peritonitis

We describe a case of peritonitis caused by Aureobasidium pullulans in a patient on continuous ambulatory peritoneal dialysis (CAPD). This dematiaceous fungus rarely causes infection in humans and to date has not been reported as an etiology of CAPD-associated peritonitis. The patient was managed successfully with peritoneal catheter removal and a prolonged course of intravenous amphotericin B, allowing resumption of CAPD. In vitro susceptibility testing confirmed sensitivity of this organism to amphotericin B.

Hyperosmolality impairs ammonia-mediated inflammation: implications for the renal medulla

Although ammonia modifies the third component of complement (C3) and activates the alternative pathway, inflammation is not seen in the renal medulla where ammonia concentrations are normally elevated. We examined the effect of the unique hyperosmolar milieu of the renal medulla on the interaction of ammonia with C3 and the capacity of ammonia-modified C3 (NH3.C3) to induce cytolytic injury and stimulate neutrophils (PMN). Incubation of purified human C3 with ammonia in concentrations found in urine results in significant disruption of the C3 thiolester bond compared with ammonia-free controls. Coincubation with urinary osmolytes and hyperosmolar NaCl and urea does not impair thiolester disruption over a range of ammonia concentrations. However, hyperosmolar NaCl and urea virtually abolish cytolytic injury mediated by the alternative pathway. Coincubation with the organic osmolytes betaine, sorbitol, and inositol fails to reverse this inhibitory effect of hyperosmolar NaCl and urea. Hyperosmolar NaCl and urea also suppress lytic injury mediated by ammonia and complement in MDCK, a cell line derived from canine distal tubular epithelium. Both PMN degranulation and respiratory burst responses to NH3.C3 are significantly blunted in the presence of hyperosmolar NaCl and urea. Hyperosmolality also impairs PMN responses to the formyl peptide N-formyl-Met-Leu-Phe and phorbol 12-myristate 13-acetate (PMA). Therefore, in an in vitro setting of hyperosmolar NaCl and urea, amidation of C3 occurs, but subsequent membrane-directed and receptor-mediated functions of NH3.C3 are markedly impaired.(ABSTRACT TRUNCATED AT 250 WORDS)

Hydrogen peroxide-induced renal injury. A protective role for pyruvate in vitro and in vivo

Hydrogen peroxide (H2O2) contributes to renal cellular injury. alpha-Keto acids nonenzymatically reduce H2O2 to water while undergoing decarboxylation at the 1-carbon (1-C) position. We examined, in vitro and in vivo, the protective role of sodium pyruvate in H2O2-induced renal injury. Pyruvate effectively scavenged H2O2 in vitro, and suppressed H2O2-induced renal lipid peroxidation. Injury to LLC-PK1 cells induced by hydrogen peroxide was attenuated by pyruvate to an extent comparable to that seen with catalase. Studies utilizing [1-14C]pyruvate further demonstrated 1-C decarboxylation concurrent with cytoprotection by pyruvate from H2O2-induced injury. Pyruvate was also protective in vivo. Infusion of pyruvate before and during the intrarenal infusion of H2O2 attenuated H2O2-induced proteinuria. Systemic administration of pyruvate was also protective in the glycerol model of acute renal failure, a model also characterized by increased generation of H2O2. These findings indicate that pyruvate, a ubiquitous alpha-keto acid, scavenges H2O2 and protects renal tissue in vitro and in vivo from H2O2-mediated injury. These data suggest a potential therapeutic role for pyruvate in diseases in which increased generation of H2O2 is incriminated in renal damage.

Prevalence of coronary heart disease in Scotland: Scottish Heart Health Study

Data from 10,359 men and women aged 40-59 years from 22 districts in the Scottish Heart Health Study were used to describe the prevalence rates of coronary heart disease in Scotland in 1984-1986 and their relation to the geographical variation in mortality in these districts. Prevalence was measured by previous history, Rose chest pain questionnaire, and the Minnesota code of a 12 lead resting electrocardiogram. The prevalence of coronary heart disease in Scotland was high compared with studies from other countries that used the same standardised methods. A history of angina was more common in men (5.5%) than in women (3.9%), though in response to the Rose questionnaire 8.5% of women and 6.3% of men reported chest pain. A history of myocardial infarction was three times more common in men than women, as was a Q/QS pattern on the electrocardiogram. There were significant correlations between the different measures of coronary prevalence. District measures of angina correlated well with mortality from coronary heart disease, and these correlations tended to be stronger in women than in men. There was no significant correlation between mortality from coronary heart disease and measures of myocardial infarction. The study provides data on the prevalence of coronary heart disease in men and women that are valuable for the planning of cardiological services.

Evaluation of two formulations of dihydrocodeine using patient-controlled analgesia

A randomised, double-blind study of 90 patients after cardiac bypass surgery was undertaken to assess the relative analgesic efficacies of normal- and controlled-release oral dihydrocodeine. Patients received either placebo, normal-release dihydrocodeine, or controlled-release dihydrocodeine at regular intervals on the first to third days after operation. This was supplemented in all groups by intravenous morphine administered on demand by a patient-controlled analgesia system. Morphine requirements in the control group were significantly greater during this 48-hour period than in either of the active groups (p less than 0.01), but there was no statistically significant difference between the two active preparations.

Evaluation of a portable measure of expired-air carbon monoxide

There are a variety of independent methods of estimating smoking status; measurement of expired air carbon monoxide has proven to be reliable and convenient. This article describes a new, inexpensive, portable analyzer for measuring expired-air carbon monoxide --the Bedfont EC50. We have compared this analyzer with the standard instrument for measuring expired-air carbon monoxide in 138 normal subjects and found good correlation and agreement. The Bedfont was demonstrated to be better at identifying smoking status, and the relevance of this finding for classification of smokers and nonsmokers by fixed-threshold carbon monoxide levels is discussed. The features of the Bedfont EC50 are particularly appealing for field and clinical use.

Intraoperative hemodialysis during cardiopulmonary bypass in chronic renal failure

This report describes the features and the course of a patient on maintenance hemodialysis in whom infective endocarditis of the aortic valve ensued. The subsequent development of intractable congestive heart failure necessitated aortic valve replacement. Use of intraoperative hemodialysis, facilitating the intraoperative and postoperative management of the patient, is described. Following valve replacement the patient did well with no evidence of congestive heart failure.

Unreliable drug histories, analgesics, and changes in renal function

One hundred and nine outpatients were questioned on their use of analgesics and asked to provide urine and blood samples. Forty-one per cent said they used analgesics daily and 54% said they had ingested analgesics during the 3 days before questioning. The analgesics used were mainly aspirin or paracetamol, alone or in combination. Five (42%) of the patients who denied the use of analgesics, and 10 (29%) of those who denied intake during the preceding week, had detectable amounts of paracetamol or aspirin in their urine. Mean serum urea, although still within the normal range, increased with increasing use of analgesics. The mean serum urea of patients who used aspirin and paracetamol in combination was significantly higher than that of those who used either of the drugs alone. The findings suggest that one should not rely heavily on the history of analgesic use, and that by replacing phenacetin with paracetamol one might not have achieved much as far as renal function is concerned.

The on-off effect in Parkinson's disease treated with levodopa with remarks concerning the effect of sleep

The "On-Off Effect" in levodopa treated Parkinson's disease began in a few patients during the first year of treatment. The number of patients suffering from this phenomenon increased rapidly the first three or four years with some continuing increase throughout the six years of the study. Even those whose disease had worsened would become even more incapacitated during parts of each day. One group of patients experienced their initial "On" effect upon arising at their usual hour of awakening. This would last for 1 to 3 hours and was their best time of day.

Human cadaver kidney preservation using hypothermic hyperosmolar, intracellular washout solution

The utilization of a hypothermic, hyperosmolar, intracellular washout solution for human kidney preservation was shown to be successful in 18 kidneys obtained from 9 heart beating cadavers. The ischemic interval ranged from 2 hrs and 57 mins to 39 hrs and 48 mins. All 18 kidneys functioned within 3 hrs of revascularization. Acute tubular necrosis with oliguria was noted in 4 of 6 patients with ischemic intervals longer than 20 hrs but not in the 12 patients obtaining kidneys preserved for 19 hrs or less. All patients with acute tubular necrosis required hemodialysis for one to 16 days post-transplantation with eventual recovery.

GLC determination of phendimetrazine in serum

A sensitive, specific, and quantitative GLC method for the determination of phendimetrazine in serum is described. The procedure involves the addition of an internal standard to serum samples, followed by extraction at pH 13 into toluene. The extracted bases are back-extracted into 1 ml of 4 M hydrochloric acid and again into 100 mu1 of chloroform after making the 4 M hydrochloric acid extract basic with 1.5 ml of 4 M sodium hydroxide. The sensitivity of the method is such that 25 ng of material can be detected in 5 ml of serum.

Thin-layer chromatographic method for determining carbamazepine and two of its metabolites in serum

A sensitive and highly specific thin-layer chromatographic method for determining simulataneously serum levels of carbamazepine and two of its major metabolites, carbamazepine-10 11-epoxide and 10, 11-dihydroxycarbamazepine, is presented. Serum (1 mug) was spotted directly onto the thin-layer plate and, after irrigation, the separated spots were converted into fluorescing compounds by exposing the plates to hydrogen chloride gas for 5 min and then to strong ultraviolet radiation from a mercury lamp for 20 min. The fluorescence was measured quantitatively using a spectrofluorimeter equipped with a thin-layer chromatogram scanning attachment. Two microlitres of serum are sufficient for a duplicate determination.