Remarkable Stability of a Molecular Ruthenium Complex in PEM Water Electrolysis

The dinuclear Ru diazadiene olefin complex, [Ru₂(OTf)(μ-H)(Me₂dad)(dbcot)₂], is an active catalyst for hydrogen evolution in a Polymer Exchange Membrane (PEM) water electrolyser. When supported on high surface area carbon black and at 80 °C, [Ru₂(OTf)(μ-H)(Me₂dad)(dbcot)₂]@C evolves hydrogen at the cathode of a PEM electrolysis cell (400 mA cm⁻², 1.9 V). A remarkable turn over frequency (TOF) of 7800 mol_H2 mol_catalyst⁻¹ h⁻¹ is maintained over 7 days of operation. A series of model reactions in homogeneous media and in electrochemical half cells, combined with DFT calculations, are used to rationalize the hydrogen evolution mechanism promoted by [Ru₂(OTf)(μ-H)(Me₂dad)(dbcot)₂].

Molecular dinuclear ruthenium complexes deposited on conducting carbon serve as active sites for the evolution of hydrogen from neutral water in a Polymer Exchange Membrane (PEM) water electrolyser.

Electrochemical CO2 reduction in water at carbon cloth electrodes functionalized with a fac-Mn(apbpy)(CO)3Br complex

The organometallic complex (fac-Mn(apbpy)(CO)3Br) (apbpy = 4-(4-aminophenyl)-2,2'-bipyridine) grafted electrochemically onto carbon cloth serves as an electrocatalyst in the aqueous reduction of CO2 to syngas. A faradaic efficiency of around 60% for CO and 40% for H2 at -1.35 V is achieved together with a productivity rate higher than 870 NlCO h-1 gMn-1 at turnover numbers of up to 33 200 during 10 hours of operation.

A Pd/C-CeO2 Anode Catalyst for High-Performance Platinum-Free Anion Exchange Membrane Fuel Cells

One of the biggest obstacles to the dissemination of fuel cells is their cost, a large part of which is due to platinum (Pt) electrocatalysts. Complete removal of Pt is a difficult if not impossible task for proton exchange membrane fuel cells (PEM-FCs). The anion exchange membrane fuel cell (AEM-FC) has long been proposed as a solution as non-Pt metals may be employed. Despite this, few examples of Pt-free AEM-FCs have been demonstrated with modest power output. The main obstacle preventing the realization of a high power density Pt-free AEM-FC is sluggish hydrogen oxidation (HOR) kinetics of the anode catalyst. Here we describe a Pt-free AEM-FC that employs a mixed carbon-CeO2 supported palladium (Pd) anode catalyst that exhibits enhanced kinetics for the HOR. AEM-FC tests run on dry H2 and pure air show peak power densities of more than 500 mW cm(-2) .

Heat treated carbon supported iron(ii)phthalocyanine oxygen reduction catalysts: elucidation of the structure–activity relationship using X-ray absorption spectroscopy

Correlation between atomic structure and oxygen reduction activity by X-ray absorption spectroscopy.

Direct alcohol fuel cells: toward the power densities of hydrogen-fed proton exchange membrane fuel cells

A 2 μm thick layer of TiO2 nanotube arrays was prepared on the surface of the Ti fibers of a nonwoven web electrode. After it was doped with Pd nanoparticles (1.5 mgPd  cm(-2) ), this anode was employed in a direct alcohol fuel cell. Peak power densities of 210, 170, and 160 mW cm(-2) at 80 °C were produced if the cell was fed with 10 wt % aqueous solutions of ethanol, ethylene glycol, and glycerol, respectively, in 2 M aqueous KOH. The Pd loading of the anode was increased to 6 mg cm(-2) by combining four single electrodes to produce a maximum peak power density with ethanol at 80 °C of 335 mW cm(-2) . Such high power densities result from a combination of the open 3 D structure of the anode electrode and the high electrochemically active surface area of the Pd catalyst, which promote very fast kinetics for alcohol electro-oxidation. The peak power and current densities obtained with ethanol at 80 °C approach the output of H2 -fed proton exchange membrane fuel cells.

Energy and chemicals from the selective electrooxidation of renewable diols by organometallic fuel cells

Organometallic fuel cells catalyze the selective electrooxidation of renewable diols, simultaneously providing high power densities and chemicals of industrial importance. It is shown that the unique organometallic complex [Rh(OTf)(trop2NH)(PPh3)] employed as molecular active site in an anode of an OMFC selectively oxidizes a number of renewable diols, such as ethylene glycol , 1,2-propanediol (1,2-P), 1,3-propanediol (1,3-P), and 1,4-butanediol (1,4-B) to their corresponding mono-carboxylates. The electrochemical performance of this molecular catalyst is discussed, with the aim to achieve cogeneration of electricity and valuable chemicals in a highly selective electrooxidation from diol precursors.

Polyketone Nanocomposites by Palladium-Catalyzed Ethylene-Carbon Monoxide-(Propene) Co(Ter)polymerization Inside an Unmodified Layered Silicate

Composites from Na-montmorillonite with a content in inorganic material ranging from 3 to 98 wt % were prepared in situ either by copolymerization of ethylene and CO or by terpolymerization of ethylene, propene and CO using a palladium(II) catalyst modified with 1,3-bis(diphenylphosphino)propane. This catalytic system is active in polar media and allowed to produce nanocomposites starting from unmodified Na-montmorillonite in water-methanol solutions. The morphological analysis, performed on samples with less than 40 wt % silicate by XRD and TEM, showed the formation of either intercalated or exfoliated (nanocomposite) structures, depending on the initial amount of the layered silicate in the reactor as well as the presence of propene as comonomer. Improved thermal stability of the hybrid materials, as compared to the corresponding organic polymers, was shown by TGA. A preliminary study of the blending of some polyketone nanocomposites with polyamide (nylon-6) was carried out by melt mixing at high temperature in a Brabender mixer.

Correlating phenotype and genotype in the periodic paralyses

BACKGROUND

Periodic paralyses and paramyotonia congenita are rare disorders causing disabling weakness and myotonia. Mutations in sodium, calcium, and potassium channels have been recognized as causing disease.

OBJECTIVE

To analyze the clinical phenotype of patients with and without discernible genotype and to identify other mutations in ion channel genes associated with disease.

METHODS

The authors have reviewed clinical data in patients with a diagnosis of hypokalemic periodic paralysis (56 kindreds, 71 patients), hyperkalemic periodic paralysis (47 kindreds, 99 patients), and paramyotonia congenita (24 kindreds, 56 patients). For those patients without one of the classically known mutations, the authors analyzed the entire coding region of the SCN4A, KCNE3, and KCNJ2 genes and portions of the coding region of the CACNA1S gene in order to identify new mutations.

RESULTS

Mutations were identified in approximately two thirds of kindreds with periodic paralysis or paramyotonia congenita. The authors found differences between the disorders and between those with and without identified mutations in terms of age at onset, frequency of attacks, duration of attacks, fixed proximal weakness, precipitants of attacks, myotonia, electrophysiologic studies, serum potassium levels, muscle biopsy, response to potassium administration, and response to treatment with acetazolamide.

CONCLUSIONS

Hypokalemic periodic paralysis, hyperkalemic periodic paralysis, and paramyotonia congenita may be distinguished based on clinical data. This series of 226 patients (127 kindreds) confirms some clinical features of this disorder with notable exceptions: In this series, patients without mutations had a less typical clinical presentation including an older age at onset, no changes in diet as a precipitant, and absence of vacuolar myopathy on muscle biopsy.

[Migraine and MIDAS (MIDASELA) in Colombian hospital workers]

AIMS

The aim of this study was to determine the prevalence of migraine and its implications in the occupational and outside employment/daily activities of the workers at a regional hospital in the Cundiboyacense Plateau in Colombia.

PATIENTS AND METHODS

The available members of the house staff at this institution were interviewed by applying the neuroepidemiological protocol drawn up by the World Health Organization (WHO); general doctors performed the initial screening and the determination of neurological disease was carried out by a clinical neurologist, both in patients who were positive and negative for neurological disease. Quality of life was evaluated by means of the MIDAS (Migraine Disability Assessment) survey, MIDASELA (in Spanish for Latin America); the analysis was performed using the EPI 6.04 software application.

RESULTS

A total of 238 people were studied: 188 females and 50 males; the prevalence of migraine was 22.5% (15.5% by the WHO protocol and 7% false negatives), with predominance in females (OR: 5.49; p< 0.005). In the MIDASELA questionnaire, 47.2% of the patients had a 50% alteration in their productivity, with regard to their occupational and outside employment/daily activities. A minimum number of patients (3.8%) were unable to work because of migraine, as compared to the figures for outside employment/daily activities (29.7%) or those involving leisure/family (66.4%). The average work, outside employment/daily and family time lost per patient because of migraine was 0.3, 2 and 5.2 days, respectively.

CONCLUSION

A sub register in the prevalence of migraine could be reported in places where the WHO protocol is used. This pathology will have to be taken well into account in Colombian hospital workers due to its individual, occupational, family, social and economic impact. It is necessary to introduce health policies and programmes aimed at evaluating, controlling and treating this type of pathology in an appropriate manner, in order to improve the quality of life of those whose job it is to look after and improve that of the other Colombians.

The late nonfunctioning duodenal atresia repair--a second look

BACKGROUND/PURPOSE

In 1986, the authors reported on 3 newborns who had repair of their duodenal atresia, and between 6 and 18 months postoperatively an anastomotic obstruction developed in each suddenly. After prolonged medical and surgical treatments it became apparent that the duodenal atresia repair was functionally obstructed and plication of the dilated atonic proximal duodenum was curative. Since then, 2 more patients became so obstructed at 5 and 24 years postoperatively. The aim of this study was to report the very late occurrence of a functional obstruction of a newborn duodenal atresia repair.

METHODS

The 2 additional histories and surgical repairs were reviewed.

RESULTS

The 5-year old boy was cured immediately with plication only of his dilated proximal duodenum. The 24-year-old nurse had a very stormy 2-year course with several bypass operations, which did not relieve her abdominal pain and bile vomiting until they were taken down and her dilated proximal duodenum was plicated, after which she made a good recovery. Both remain well.

CONCLUSION

An uncommon, very late, sudden, apparently anastomotic, postoperative, newborn, duodenal atresia repair obstruction caused by proximal, dilated, duodenal atony, and dysfunction can occur many years later and responds to duodenal plication alone.

Modulation of endogenous GABA release by an antagonistic adenosine A1/dopamineD1 receptor interaction in rat brain limbic regions but not basal ganglia

Behavioral and biochemical studies suggest that a negative interaction exists between adenosine A(1) and dopamine D(1) receptors in the brain and that this may contribute to the psychomotor effects of adenosine receptor agonists and antagonists. We examined the functional significance of A(1) and D(1) receptor subtypes in modulating electrically evoked endogenous GABA release from slices/punches of rat basal ganglia (striatum, globus pallidus, striatum containing globus pallidus, and substantia nigra reticulata) and limbic regions (ventral pallidum and nucleus accumbens). In basal ganglia, stimulation of A(1) receptors with the selective agonist R-PIA (1-100 nM) resulted in a concentration-dependent decrease in GABA release. The selective A(1) antagonist DPCPX (10-100 nM) increased GABA release, suggesting that endogenous adenosine tonically inhibits GABA release. However, in basal ganglia, consistent dopamine D(1) receptor modulation of GABA, release was not observed in response to either D(1) agonists or antagonists. Furthermore, the A(1) receptor-mediated inhibition of GABA release was not changed by concurrent activation of D(1) receptors, thus confirming the lack of D(1) receptor modulation under these conditions. In contrast, in ventral pallidum and nucleus accumbens, stimulation of D(1) receptors with SKF-82958 (1 microM) increased GABA release significantly. The D(1) receptor-mediated increase in GABA release was attenuated by concurrent activation of adenosine A(1) receptors. These results are consistent with the hypothesis that an antagonistic A(1)/D(1) receptor interaction may be important in modulating GABA release in limbic regions.

Partial tracheal obstruction due to chondromas in ball pythons (Python regius)

Over a 9-mo period, three adult ball pythons (Python regius) (one male, two females) were evaluated for severe dyspnea. Partial obstructions of the tracheal lumen were identified radiographically and/or visualized with a 3.0-mm rigid laparoscope inserted into the tracheal lumen in all three snakes. Administration of systemic antibiotics and nebulization resulted in partial improvement of the dyspnea. In two snakes, the tracheal lesions were removed with a rigid laparoscope and a flexible biopsy instrument inserted into the tracheal lumen. The other snake died and was necropsied. Histologically, the lesions from two snakes were determined to be benign chondromas. The chondromas were composed of a variably disorganized chondroid matrix populated by quiescent, normal-appearing chondrocytes within lacunae, although the chondrocytes were increased in density compared with normal hyaline cartilage and contained rare mitotic figures. The tracheal masses in one snake grew by expansion, not invasion, and were focally continuous with a mineralized cartilage tracheal ring, suggesting a benign nature. This is the second report of tracheal chondroma in ball pythons. Tracheal chondromas are exceedingly rare in humans and domesticated animals, suggesting a possible predisposition of ball pythons for this neoplasm.

On the possible role of positive end-expiratory pressure ventilation in the treatment of chylothorax caused by blunt chest trauma

Recent reports on the treatment of chylothorax postulate a benefit to ventilator therapy, especially using positive end-expiratory pressure (PEEP). This report describes the use of mechanical ventilation with PEEP in the management of a 24-year-old male motorcyclist who sustained a ligamentous Chance fracture of the thoracic spine at the T6-7 level with bilateral traumatic chylothorax. Treatment of the chylothorax consisted of high PEEP ventilation, bilateral chest tube thoracostomies, and total parenteral nutrition. The chylothoraces resolved within 4 days of treatment and mechanical ventilation was stopped. Ventilator therapy of traumatic chylothorax and the physiologic grounds for its use are discussed. A review of the literature and experimental evidence seem to suggest that ventilator treatment of traumatic chylothoraces is effective.

Expression and modulation of 5-hydroxytryptamine1A receptors in P11 cells

P11 cells were transfected with DNA for the human 5-hydroxytryptamine1A (5-HT1A) receptor. These cells stably expressed the 5-HT1A receptor coupled to the inhibition of adenylyl cyclase, and not to the stimulation of phosphoinositide hydrolysis. Homologous and heterologous regulation of the 5-HT1A receptor was studied in this cell system. Pretreatment of P11-5HT1A cells with the 5-HT1 receptor agonist 5-carbox-amidotryptamine (5-CT) resulted in a 3-fold increase in both basal and forskolin-stimulated cAMP accumulation, and desensitization of the 5-HT1A receptor as indicated by a decrease in the potency of 8-hydroxydipropylaminotetralin (8-OH-DPAT) to inhibit forskolin-stimulated cAMP accumulation (vehicle-treated cells: EC50 = 2.3 +/- 0.8 nM; 5-CT-treated cells: 9.9 +/- 0.4 nM). The sensitization of adenylyl cyclase as a result of chronic agonist exposure was prevented by the 5-HT1A antagonist WAY100635, which indicated that the effect of 5-CT pretreatment on basal and forskolin-stimulated cAMP accumulation was mediated by 5-HT1A receptor activation. Pretreatment of cells with pertussis toxin abolished the inhibition of forskolin-stimulated cAMP accumulation mediated by 5-HT1A receptor activation and prevented the sensitization of adenylyl cyclase as a result of chronic 5-HT1A receptor agonist exposure. Pretreatment of P11-5HT1A cells with the phorbol ester, phorbol 12-myristate 13-acetate (PMA), also resulted in desensitization of the 5-HT1A receptor, as indicated by a marked decrease in the potency and intrinsic activity of 8-OH-DPAT. No change in the binding characteristics (i.e., Kd or Bmax) of [3H]8-OH-DPAT to 5-HT1A receptor sites was observed after 5-CT or PMA treatments. Activation of alpha-1 adrenergic receptors, but not 5-HT2A receptors, had effects on 5-HT1A receptor responsiveness similar to those seen with PMA pretreatment. In P11-5HT1A cells, homologous regulation of the 5-HT1A receptor was characterized by sensitization of adenylyl cyclase and a decrease in agonist potency, whereas heterologous regulation of the 5-HT1A receptor was characterized by a greater decrease in agonist potency, as well as a marked decrease in intrinsic activity.

Expression of the human 5-hydroxytryptamine1A receptor in Sf9 cells. Reconstitution of a coupled phenotype by co-expression of mammalian G protein subunits

The possibility that Spodoptera frugiperda (Sf9) cells can provide an intact cell setting for reconstitution of the human 5-hydroxytryptamine1A (5-HT1A) receptor with mammalian G protein subunits was explored. The 5-HT1A receptor was found to assume an uncoupled phenotype when expressed alone in Sf9 cells at relatively high levels (5-34 pmol of receptor/mg of membrane protein), i.e. agonist-binding to the receptor was characterized by a relatively high Kd and an insensitivity to GTP. Co-expression of the receptor with members of the alpha i "family" together with various combinations of beta 1 and gamma subunits increased the affinity for agonists to that observed for the coupled form of receptor in mammalian cells, concomitant with conferrance of guanosine 5'-(beta,gamma-imino)triphosphate sensitivity. The agonists employed were [3H]8-hydroxy-N,N-dipropyl-2-aminotetralin ([3H]8-OH-DPAT) and [125I]R(+)-trans-8-hydroxy-2-[N-n-propyl-N-(3'-iodo-2'-propenyl) amino]tetralin ([125I]8-OH-PIPAT). The binding of an antagonist, [125I]4-(2'-methoxyphenyl)-1-[2'-[N-(2"- pyridinyl)-p-iodobenzamido]ethyl]piperazine ([125I]p-MPPI), was unaffected by co-expression of G protein subunits. Both alpha and beta gamma subunits were required for optimal coupling. No differences were evident among alpha i1, alpha i2, alpha i3, alpha o, and alpha z when expressed with beta 1 gamma 2 in this regard, nor among most permutations of beta 1 gamma subunits when expressed with alpha i1 (beta 1 gamma 2 approximately beta 1 gamma 3 approximately beta 1 gamma 5 > beta 1 gamma 1). Alpha s and alpha q expressed with beta 1 gamma 2 did not participate in coupling. These data support the conclusion that normal interactions between a mammalian receptor and a select array of G proteins can be established in intact Sf9 cells, and extend previous observations of 5-HT1A receptor coupling to G(o) and the pertussis toxin-insensitive G protein Gz.

Dexamethasone recruits atrial natriuretic peptide secretory cells in the rat left atrium and apex of the ventricle

The response of the atrial natriuretic peptide (ANP) secreting cells from both rat atria and the apex of the ventricles to dexamethasone (DEX) was analyzed by the plaque assay. In right atrial cardiocytes, 25% of the cells secreted ANP basally; DEX treatment did not alter this percentage. However, in the left atrial secretory population, a discordance between the basal (15%) and DEX stimulated (25%) percent plaque formation was found. ANP secreting cells from the ventricular apex responded similarly to DEX exposure (26%), with 8% of the cells basally releasing the hormone. These data suggest that in both the left atria and apex of the rat ventricles, exposure to DEX recruits ANP secretory cells from a non-secreting population. Consequently, the release of ANP from these tissues would increase after glucocorticoid stimulation.

Induction of an acute phase response in lambs causes an increase in plasma levels of GH and IGF-I

GH and IGF-I plasma concentrations were measured in lambs during an acute phase response induced by an intrathoracic injection of yeast. The acute phase response was indicated by reduced feed intake, weight loss and an increase in plasma concentrations of the acute phase protein haptoglobin. Intensive blood sampling on day 1 revealed elevated basal concentrations of GH in the yeast-injected group compared with concentrations in pair weight and ad libitum fed control lambs. This suggests that at the beginning of an acute phase response there is an increase in either GH secretion or the half life of GH. No evidence of a specific GH-binding protein in sheep plasma could be detected. IGF-I concentrations in the yeast-injected group remained constant for 3 days then increased to a peak level at day 6. In contrast, plasma IGF-I concentrations were depressed from days 3 to 6 in the pair weight control group and they were unchanged in the ad libitum fed controls. When the IGF-I concentrations were elevated in the yeast-injected group, this group had a higher daily weight gain despite their lower feed intake compared with the ad libitum fed controls. These results suggest that IGF-I may be associated with the increase in weight in the late stage of an acute phase response during recovery from an infection or injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Proportions of rat ANP-secreting cells that are cardiomyocytes and that synthesize the hormone

Atrial natriuretic peptide (ANP) is released from the heart and participates in regulating blood pressure and volume. We recently developed a reverse hemolytic plaque assay to measure the release of ANP from individual rat atrial cardiocytes. This assay determines the total proportion of atrial cardiocytes committed to releasing ANP. We combined the plaque assay with immunocytochemistry (IC) and in situ hybridization (IS). Combining the plaque assay with IC for myosin revealed that 13.5 +/- 0.9% (%myosin+ and plaque forming; mean +/- SE, n = 4) of atrial cardiocytes are cardiomyocytes that release ANP. Combination of the plaque assay with IS for ANP mRNA showed that 16.6 +/- 0.6% (%in situ+ and plaque forming; mean +/- SE, n = 4) of the cardiocytes in the rat atria synthesize and release the hormone. Incubation of atrial cardiocytes with dexamethasone to stimulate ANP gene expression did not alter the total proportion of in situ-positive ANP-secreting cells. These data suggest that, within the total ANP-secreting population of the rat atria, only 33% of the secreting cells are cardiomyocytes. In addition, 68% of the ANP-secreting cells do not appear to synthesize the hormone. These results imply that muscle and nonmuscle cells are involved in secreting ANP and that cardiomyocytes synthesize the hormone.

Unsuspected tracheal rupture in blunt thoracic trauma

The purpose of this report is to describe the discovery and management of an unanticipated injury during fibreoptic tracheal intubation. A 23-yr-old man sustained blunt cervical, thoracic and abdominal trauma in a motor vehicle accident. He was brought to the operating room for urgent management of his abdominal and cervical spine injuries. Examination of his airway during awake fibreoptic tracheal intubation revealed an unexpected tracheal injury. Surgical repair of the trachea was uneventful. The diagnosis and airway management of tracheal rupture are discussed. This case illustrates the importance of a full diagnostic examination during invasive anaesthetic procedures such as tracheal intubation.

Dexamethasone stimulates release of an ANP-like substance from rainbow trout cardiocytes

A substance that cross-reacts with antiserum to human atrial natriuretic peptide (ANP) is found in fish hearts. This ANP-like material increases sodium output from the gill and kidney while inhibiting sodium uptake in the gut. Mammalian ANP secretion is stimulated by glucocorticoids, and cortisol injection increases sodium output in salt-loaded fish. Therefore, we wanted to determine if the release of ANP in fish is sensitive to dexamethasone. Ventricle cardiocytes from the rainbow trout Oncorhynchus mykiss were treated with various doses of dexamethasone for 18 or 72 h. Single ventricle cells were then assayed for ANP release using a reverse hemolytic plaque assay and antiserum to human alpha-ANP. Incubation with 100 microM dexamethasone almost doubled the population of ventricle cells committed to ANP release (basal, 15.0 +/- 0.3% vs. Dexamethasone, 28.3 +/- 1.4%; values are percent plaque formation +/- SE). Stimulation of ANP secretion was dependent on dose and time of exposure to dexamethasone. These results suggest that ANP secretion in fish is regulated by glucocorticoids.

Release of atrial natriuretic peptide from individual rat cardiocytes

Atrial natriuretic peptide (ANP) is released from the atria and acts to regulate blood volume and pressure. The release of ANP appears to be stimulated by atrial distension, initiated by stretch on the cardiocytes. The purpose of the present study was to develop an assay that would allow for the detection of ANP release from single, isolated cells in the absence of distension. Using the reverse hemolytic plaque assay and antibody raised against human-alpha ANP, the release of ANP was detected from trypsin dissociated rat atrial cells. The specificity of the assay was demonstrated by a 67% reduction in ANP plaque forming cells detected following preabsorption of the anti-sera with rat-alpha ANP. The assay also proved efficient in monitoring changes in ANP secreting cell populations, where an acute treatment with dexamethasone resulted in a doubling of the percentage of atrial cardiocytes detected within a 4 hour antibody incubation. Finally, the assay established that about 52% of the dispersed atrial cardiocytes release ANP. The establishment of a plaque assay for ANP release should assist in addressing questions concerning what hormones may regulate ANP secretion directly and also allow for the determination of ANP secreting cell population dynamics.

Ontogeny of prolactin secretion in the neonatal rat is regulated posttranscriptionally

PRL-secreting cells first appear in appreciable numbers on day 4 of neonatal life in rats. In the present study, we attempted to ascertain whether the ontogenic appearance of PRL mRNA and hormone release were temporally coordinated or discordant. Our results show that the PRL gene is expressed at least 3 days before the onset of secretion in newborn rats. Moreover, steady state levels of PRL mRNA in neonates are at least as high as those found in 10-day-old rats, in which 15-17% of all pituitary cells secret the hormone. This apparent blockage of translation is attributable to a lack of association of PRL message with ribosomes in the neonate. Taken together, these data indicate that the ontogeny of PRL secretion in rats is regulated translationally as well as transcriptionally.

Liver tissue from lactating rats produces a factor that stimulates prolactin release and gene expression

Liver tissue from nursing rats produces a substance, termed liver lactogenic factor (LLF), that potently stimulates casein release from isolated mammary cells. Inasmuch as the production of LLF is dependent on PRL, we decided to determine whether it could influence the release of the hormone by dissociated pituitary cells in culture. This was accomplished by measuring PRL release with a reverse hemolytic plaque assay and PRL gene expression with a DNA probe complementary to PRL mRNA. Treatment of pituitary cells from day 10 lactating rats with liver slice incubates from the same type of animal caused a 35.3 +/- 4.3% increase in PRL release during a 3-h incubation. Likewise, the same dose of LLF activity markedly increased (3.5-fold) the steady state levels of PRL mRNA. The responses were reasonably specific for PRL, since neither GH plaque development nor gene expression was affected by identical treatment. Taken together these results demonstrate that LLF can act directly at the pituitary level to exert positive feedback effects on both PRL release and gene expression.

Evidence for a cAMP-dependent nuclear factor capable of interacting with a specific region of a eukaryotic gene

Nuclear extracts prepared from the livers of rats treated with or without 8-bromo-cAMP were tested for their ability to bind to various fragments from the flanking region of the gene encoding phosphoenolpyruvate carboxykinase (GTP) [GTP: oxaloacetate carboxy-lyase (transphosphorylating), EC 4.1.1.32] known to contain the element that confers transcriptional regulation by cAMP. Using the nitrocellulose-filtration method, concentration-dependent, apparently saturable binding was seen that is both specific and cAMP dependent. Analysis of various fragments pinpointed the active binding region to positions within the -67 to -111 region, which coincides with the functional regulatory element as shown by recent transfection studies. Formation of an apparently single complex between a synthetic oligomer containing the region from -67 to -111 of the phosphoenolpyruvate carboxykinase gene and a factor in nuclear extracts from cAMP-treated rat liver was visualized by the gel-retardation method. Complex formation is both concentration and cAMP dependent and can be prevented by excess specific but not nonspecific competitor DNA. The congruity of the results with the two different methods suggests that the factor we have detected has properties consistent with a possible role as mediator of the transcriptional control exerted by cAMP in eukaryotic cells.

Attenuation of growth hormone gene expression in desensitized somatotropes

The effects of GRF-induced desensitization of somatotropes on GH gene expression were investigated on pituitary cells derived from male rats. Pretreatment of monodispersed cells for 18 hr with GRF abolished both the acute release of GH and the stimulation of GH gene expression in response to a subsequent 4 hr challenge with GRF. Concomitant preincubation with GRF and SS resulted in restoration of the ability of GRF to stimulate release of GH but not to augment GH gene expression. These results demonstrate that desensitization by GRF affects both the release of GH and GH gene expression, whereas the resensitizing effects of SS appear to be directed exclusively at the release mechanism.

Blunt liver trauma at Sunnybrook Medical Centre

Between 1 June 1976 and 30 June 1985 Sunnybrook Medical Centre Regional Trauma Unit admitted 2,016 patients of whom 220 (11%) sustained liver injury. Of these 220 patients, 211 (96%) sustained blunt liver trauma; 175 of 176 patients who underwent open peritoneal lavage had a true positive lavage. Resuscitation was successful in 212 patients, of whom 209 underwent laparotomy and three were treated nonoperatively: 129 of 209 patients (62%) required only minor surgical treatment; the remaining 80 patients (38%) required major surgical procedures. The overall mortality was 29% (64/220). Eight patients died during resuscitation, one of them of liver hemorrhage. Of the 56 patients who died after admission, the cause of death was head injury in 31, liver hemorrhage in 11 (five intraoperatively) and 14 died of other causes. Overall, liver hemorrhage was the cause of death in 12 of 64 deaths (19%). In other words, 12 of the total of 220 patients (6%) died from liver-related mortality.

Abdominopelvic computerized tomography and open peritoneal lavage in patients with blunt abdominal trauma: a prospective study

This prospective trial compares abdominopelvic computerized tomography and open peritoneal lavage in the diagnosis of blunt abdominal trauma. Fifteen patients (group 1) were evaluated by both methods. Another 15 patients (group 2) had only computerized tomography. Criteria for a "positive" scan were hemoperitoneum and evidence of solid organ injury. Criteria for "positive" lavage were a grossly bloody return, erythrocyte count greater than 20.0 X 10(9)/L and leukocyte count greater than 0.5 X 10(9)/L. At laparotomy, only injuries requiring repair or excision were considered "true positive". Patients who did not have laparotomy and had an uncomplicated clinical course were considered "true negative". With tomographic criteria alone for diagnosis there would have been one false-positive and three false-negative results, compared with three false positive and no false negatives for open peritoneal lavage alone. None of the three patients who had negative findings on laparotomy suffered any morbidity or died. Results of computerized tomography and open peritoneal lavage agreed in 8 of 15 patients (kappa value = 0.52), indicating a low level of agreement between the two. The authors believe that open peritoneal lavage remains the diagnostic procedure of choice in blunt abdominal trauma.

Elastofibroma: chest wall pseudotumor

A 68-year-old man had a painless, nontender lump in the right infrascapular region. An unenhanced computed tomography (CT) scan showed a soft-tissue mass attached to the scapula, causing muscular displacement. A similar, smaller mass was found on the left side. The appearance of the masses on CT scans was suggestive of infiltrating malignancy, but pathologic examination disclosed findings typical of elastofibroma. Biopsy is recommended in similar cases to exclude sarcoma.

Blunt liver trauma at the Sunnybrook Regional Trauma Unit

Between June 1, 1976 and Mar. 31, 1983, the Sunnybrook Medical Centre Regional Trauma Unit in Toronto, Ont., admitted 145 patients with liver trauma; of these, 141 (97%) had sustained blunt liver trauma. Of 113 patients who underwent open peritoneal lavage, 112 had a true-positive lavage. Resuscitation was successful in 137 patients and 134 of these underwent laparotomy. Seventy-nine (59%) of the 134 patients required only minor surgical treatment; the other 55 (41%) required major surgical procedures. The overall mortality was 32% (47 of 145). Eight patients died during resuscitation but only one of them died of liver hemorrhage. Of the 39 patients who died after admission, the cause of death was head injury in 22, while 6 died of liver hemorrhage and 11 of other causes. Overall, liver hemorrhage was the cause of death in 15% of cases (7 of 47).

Analysis of peritoneal lavage parameters in blunt abdominal trauma

Peritoneal lavage is the most valuable diagnostic modality presently available for the evaluation of patients with blunt abdominal trauma. A retrospective review of 523 patients who underwent open peritoneal lavage for blunt abdominal trauma over a 3 1/2-year period revealed serious intra-abdominal pathology in 83% of patients undergoing laparotomy with RBC lavage counts in the range of 20,000 to 100,000 cells/mm3, a level considered by many authors to be negative or indeterminate. Two patients with isolated small bowel perforations had an elevated amylase level as the only measured abnormality. The data indicate that the standard guidelines for RBC positivity (positive count greater than 100,000 cells/mm3 and indeterminate count 50,000 to 100,000 cells/mm3) result in missed intraperitoneal injuries in a large percentage of patients and therefore require reevaluation. Lavage amylase determinations, previously stated to be costly and of insignificant yield, should be performed on patients whose lavage would otherwise be considered negative by RBC and WBC counts.

Blunt splenic trauma: diagnosis and management

To examine the morbidity and mortality associated with blunt splenic injuries, the authors reviewed the results in 106 such patients treated in the Sunnybrook Regional Trauma Unit between June 1, 1976 and June 30, 1983. Initial assessment included peritoneal lavage in 86 patients. No patient with known or suspected splenic injury was treated nonoperatively nor were any patients found to have had splenic injuries missed at the initial assessment. Seventy-one splenectomies and 35 splenorrhaphies were performed. The overall mortality was 25% and 10 surviving patients had serious complications. The splenic injury itself was never the cause of death. Only one patient who initially underwent splenorrhaphy later required splenectomy. It is concluded that blunt splenic injury is rarely the cause of death or serious morbidity when a policy of immediate diagnosis and operative treatment is carried out. Furthermore, in selected patients, splenorrhaphy is a safe and effective treatment.

Management of flail chest

This paper compares the management of two groups of patients with flail chest. The 25 patients in group 1 had a flail chest without other significant injuries or shock, whereas the 57 in group 2 had a flail chest with multiple injuries, shock or both. The group 1 patients were treated with repeated multiple intercostal nerve blocks or high segmental epidural analgesia, oxygen, intensive chest physiotherapy, fluid restriction, furosemide diuretics, methylprednisolone sodium succinate and colloid infusion in an intensive care unit. In addition to these measures, the group 2 patients underwent endotracheal intubation and assisted mechanical ventilation with a volume respirator that provided continuous positive airway pressure and positive end-expiratory pressure. Of the 57 group 2 patients 36 required prolonged ventilation, eventually through a tracheostomy, because of severe head injury, pneumonia, severe facial injury, quadriplegia, pre-existing lung disease or severe sepsis. However, tracheostomy was avoided in the other 21 patients in group 2. There were no deaths in group 1, but 8 (14%) of the patients in group 2 died. These results show that avoidance of tracheostomy and ventilation in selected patients with flail chest is consistent with a low morbidity and mortality.

Investigation of the nature and specificity of antinuclear antibody in dogs

A liquid phase radioimmunoassay was used to test sera from 34 dogs in 3 categories, determined by presence of antinuclear antibody (ANA) and disease, for antibodies against native canine DNA and dAdT, a synthetic double-stranded DNA analog. Antibodies to dAdT were absent in healthy dogs which, as a group, had levels of DNA antibodies consistent with those reported for healthy persons. Canine patients with a variety of illnesses, but which remained ANA negative, had slightly increased levels of binding of DNA and dAdT. As a group, ANA-positive dogs had significantly increased binding of dAdT and native DNA, which was shown to be mainly, but not entirely, double stranded. In the ANA-positive group, no correlation was found among ANA titer, % DNA binding, and % dAdT binding, indicating that these 3 procedures detect antibodies with differing specificities. In dogs, ANA are heterogeneous in antigenic specificity. Antibodies to double-stranded nucleic acid in dogs do not appear to be as specific for systemic lupus erythematosus as they are reported to be in persons with autoimmune disease.

Controversies in the management of pulmonary contusion

Most polytraumatized patients with lung contusion also have injury to the chest wall. Both are serious but the lung contusion is most important in contributing to respiratory failure. A small and localized injury to the lung leads to generalized edema in surrounding lung and even in the opposite lung. The permeability of capillaries is affected and there is an outpouring of the fluid through a leaking pulmonary membrane. Diagnosis is easy when the condition is straightforward and severe, but may be complicated in a confused or unconscious patient with or without head, abdominal and orthopedic injuries producing shock. Pulmonary aspiration and pneumonia may cloud the issue. Aggressive chest physiotherapy combined with the reduction of pain by local intercostal blockade or epidural anesthesia may obviate the need for mechanical ventilation.