Enzymology of oxidation of tropic acid to phenylacetic acid in metabolism of atropine by Pseudomonas sp. strain AT3

Pseudomonas sp. strain AT3 grew with dl-tropic acid, the aromatic component of the alkaloid atropine, as the sole source of carbon and energy. Tropic acid-grown cells rapidly oxidized the growth substrate, phenylacetaldehyde, and phenylacetic acid. Crude cell extracts, prepared from dl-tropic acid-grown cells, contained two NAD+-linked dehydrogenases which were separated by ion-exchange chromatography and shown to be specific for their respective substrates, dl-tropic acid and phenylacetaldehyde. Phenylacetaldehyde dehydrogenase was relatively unstable. The stable tropic acid dehydrogenase was purified to homogeneity by a combination of ion-exchange, molecular-sieve, and affinity chromatography. It had a pH optimum of 9.5 and was equally active with both enantiomers of tropic acid, and at this pH, phenylacetaldehyde was the only detectable product of tropic acid oxidation. The formation of phenylacetaldehyde from tropic acid requires, in addition to dehydrogenation, a decarboxylation step. By analogy with NAD+-specific isocitrate and malate dehydrogenases, phenylmalonic semialdehyde, a 3-oxoacid, would be expected to be the precursor of phenylacetaldehyde. Other workers have established that isocitrate and malate dehydrogenases catalyze the decarboxylation of enzyme-bound or added 3-oxoacid intermediates, a reaction that requires Mn2+ or Mg2+ ions. Studies with tropic acid dehydrogenase were hampered by lack of availability of phenylmalonic semialdehyde, but in the absence of added divalent metal ions, both enantiomers of tropic acid were completely oxidized and we have not, by a number of approaches, found any evidence for the transient accumulation of phenylmalonic semialdehyde.

Bacterial protease Lon is a site-specific DNA-binding protein

The product of the Escherichia coli lon gene is the ATP-dependent Lon protease. Lon contributes to the regulation of several important cellular functions, including radiation resistance, cell division, filamentation, capsular polysaccharide production, lysogeny of certain bacteriophages, and proteolytic degradation of certain regulatory and abnormal proteins. Lon homologues are also found in several widely divergent bacteria, as well as in the mitochondria of yeast and humans. E. coli Lon has long been known to bind to DNA, but this interaction has not been further characterized and has generally been assumed to be nonspecific. We now demonstrate that E. coli Lon can bind to a TG-rich DNA promoter element in a sequence-specific manner. This finding is based on the results of experiments employing SouthWestern blotting, protein purification, "shift-shift" electrophoretic mobility shift assays, electrophoretic mobility shift assays using in vitro transcribed and translated Lon, and DNase footprinting. Site-specific DNA binding is likely to be an additional important biochemical characteristic of the multifaceted Lon protease.

Contrasting effects of T cell growth factors on T cell responses to melanoma in vitro

Determinants of T cell responses to tumor cells remain largely unknown. In the present study we have used long-term cultures of human melanoma cells and autologous peripheral blood lymphocytes to examine the influence of cytokines with T cell growth activity on the phenotype and cytotoxic and proliferative response of T cells to melanoma. It was found that addition of interleukin-4 (IL-4) inhibited the response of CD8+ T cells and promoted the response of the CD4 subset. IL-2 or IL-7 was effective in increasing melanoma-specific cytotoxic T lymphocyte (CTL) activity in cultures where CD8 T cells were predominant, whereas IL-4 followed by IL-2 was most effective in cultures where CD4 T cells predominated. IL-10 or IL-12 inhibited proliferation and CTL activity against melanoma in long-term cultures. The effects of IL-12 were reproduced in long-term cultures of T cells stimulated with mAb against CD3 and were shown to depend on prior exposure of T cells to IL-12 before IL-2. As yet unidentified factors, such as co-factor expression on melanoma, appear to be as important as exogenous cytokines in determining the nature of T cell responses to melanoma. These results suggest that analysis of responses in long-term culture may assist in defining the role of key cytokines and other determinants of immune responses to melanoma.

Further studies on the suppression of luteinizing hormone release due to activation of medial preoptic-anterior hypothalamic area mu-opioid receptors

Our laboratory has previously demonstrated that specific activation of mu-opioid receptors in the medial preoptic-anterior hypothalamic area with [D-Ala2, N Me-Phe4, Gly-ol5]-enkephalin (DAGO) suppresses luteinizing hormone secretion in the ovariectomized rat [29]. In the present study, three experiments were undertaken to ascertain whether changes in the activity of norepinephrine or dopamine neurons modulate the decrease in luteinizing hormone release in response to DAGO. The first experiment utilized push-pull perfusion in conjunction with HPLC to assess in vivo norepinephrine release in the medial preoptic-anterior hypothalamic area in response to perfusion of this site with DAGO (5 micrograms/h). DAGO significantly decreased luteinizing hormone release, but perfusate norepinephrine levels did not change. In the second experiment, push-pull perfusion in the medial preoptic-anterior hypothalamic area with cerebrospinal fluid (CSF) or CSF containing DAGO was done in rats pretreated with the norepinephrine synthesis inhibitor, FLA-63. This drug pretreatment had no effect on the DAGO-induced suppression of luteinizing hormone secretion. In experiment 3, push-pull perfusion in the medial preoptic-anterior hypothalamic area with CSF followed by CSF containing DAGO was done in rats pretreated with vehicle, or a dopamine receptor antagonist, either pimozide or d-butaclamol. Neither dopamine receptor antagonist had any effect on the DAGO-induced suppression of luteinizing hormone release. Thus, these studies do not support a role for alterations in the activity of norepinephrine or dopamine neurons in mediating the suppression of luteinizing hormone release in response to activation of mu-opioid receptors in the medial preoptic-anterior hypothalamic area in the ovariectomized rat.

Thromboxane is required for full expression of angiotensin hypertension in rats

Recent studies suggest that thromboxane (TX) mediates a significant component of angiotensin II (ANG II)-induced hypertension. However, there is little information to support the hypothesis that this relationship is important during chronic, physiological increases in ANG II, particularly while controlling for variation in endogenous ANG II levels induced by TX inhibition. This study tested that hypothesis in 27 chronically instrumented rats. After baseline measurements, suppression of endogenous TX was induced and maintained throughout the study in 13 rats by i.v. infusion of the TX synthesis inhibitor (TSI) U63557A: the other 14 rats received vehicle. Baseline mean arterial pressure (MAP) was not different between groups and was unchanged by TSI or vehicle. Continuous inhibition of ANG II production was then initiated in both groups of rats by i.v. infusion of the angiotensin-converting enzyme inhibitor (ACEI) benazepril. ACEI reduced blood pressure similarly in vehicle and TSI rats, from 105 +/- 2 to 91 +/- 2 mm Hg and 103 +/- 1 to 89 +/- 1 mm Hg, respectively. ANG II was then infused at 5 ng.kg-1.min-1 i.v. for 7 days in six rats from each group to restore ANG II activity to baseline levels. This dose increased MAP to 103 +/- 2 and 101 +/- 1 mm Hg in vehicle and TSI rats, respectively, values not different from pre-ACEI levels. Seven TSI rats and eight vehicle rats received a higher dose of ANG II (20 ng.kg-1.min-1 i.v.). After 7 days, MAP was higher in vehicle than in TSI rats (143 +/- 5 versus 120 +/- 4 mm Hg). These results suggest that endogenous TX is an important determinant of MAP in ANG II hypertension but may have a diminished role in blood pressure regulation when ANG II is at normal and subnormal levels.

Expression of the co-stimulatory molecule CD40 on melanoma cells

We have previously shown that one of the co-factors required for generation of T-cell responses, B7.1, is variably expressed on melanoma cells. In the present studies we have examined the expression of another important co-factor in T-cell responses, viz., CD40, and investigated regulation of its expression and possible function(s). PCR analysis revealed mRNA for CD40 in all 18 cell lines established from metastatic melanoma and the majority of those from 6 primary melanoma. CD40 protein was detectable in approximately 50% of the cell lines by flow cytometry and in sections from only 2 of 20 melanoma. Expression of CD40 protein was increased in 2 of 3 cell lines with constitutive CD40 expression by interferon-gamma but not by granulocyte/macrophage colony-stimulating factor, interleukin-2 or tumor necrosis factor-alpha. Interaction of monoclonal antibody with CD40 on melanoma cells resulted in an increase in their cell division but did not increase expression of the costimulatory factor B7. Our results suggest that CD40 expression on melanoma may have important effects on their biology. The influence of CD40 expression on T-cell responses to melanoma remains to be investigated.

A comparative analysis of pharmacokinetics of ceftriaxone in serum and pleural fluid in humans: a study of once daily administration by intramuscular and intravenous routes

Pleural fluid and serum pharmacokinetics of ceftriaxone were performed in thirteen patients with pleural effusion. One gram of ceftriaxone was administered once daily intravenously in six patients and intramuscularly in seven patients. Ceftriaxone concentrations were measured in serum and pleural fluids in both groups on the first day of administration and in four patients of the intramuscular group on the fourth day of administration. The mean serum peak concentration at 1 h was 199 mg/L (S.E.M. 63.2) in the iv group and 80.5 mg/L (S.E.M. 12.0) in the im group. The mean serum trough concentrations in the two groups at 24 h were 27.5 mg/L (S.E.M. 12.6) and 29.7 mg/L (S.E.M. 5.2) respectively. In the pleural fluid, mean peak concentration was 20.1 mg/L (S.E.M. 4.7) at 6 h in the iv group and 15.3 mg/L (S.E.M. 5.1) at 12 h in the im group. The mean trough concentration was 9.6 mg/L (S.E.M. 1.9) and 13.3 mg/L (S.E.M. 3.1) at 24 h in the two groups respectively. On the fourth day of intramuscular administration the serum and pleural fluid peak and trough concentrations were higher when compared with the first day, consistent with a cumulative effect. The serum and pleural fluid concentrations of ceftriaxone following intravenous and intramuscular administration were well above the MIC90 of most common respiratory pathogens indicating good penetration into extracellular spaces. Further, these serum and pleural fluid antibiotic concentrations could be maintained even after a single intramuscular injection of the drug, thus indicating its usefulness as a parenteral mode of therapy on a domicilliary basis with a significant cost-saving potential. In conclusion, intramuscular administration of ceftriaxone would appear to be a convenient method of administering parenteral therapy in lower respiratory tract infections in the hospital and community, with pharmacokinetics very similar to those exhibited by the intravenous route.

Molecular phylogeny of eastern Pacific sea cucumbers (Echinodermata: Holothuroidea) based on mitochondrial DNA sequence

A molecular phylogenetic analysis of some Holothuroidea was undertaken in order to clarify the systematics and taxonomy of this class in the northeast Pacific. DNA sequence for portions of two mitochondrial genes, the large ribosomal subunit and cytochrome oxidase 1 was obtained from 16 species of sea cucumbers, including nine members of the family Cucumariidae. As reported for many mitochondrial genomes, a strong bias against G was noted in the coding strand at synonymous sites. In order to verify trees recovered in the presence of this bias, parsimony, maximum likelihood, distance, and log determinant methods were all employed. The resulting molecular phylogeny of the Cucumariidae, with a few exceptions, supported existing taxonomy which is based largely on the morphology of calcareous parts. In particular, evolutionary relationships among the brooding species were clarified. Our results confirm that C. pseudocurata Deichmann is distinct from C. curata Cowles and that these two species do not represent geographic variants of a single species. In fact C. pseudocurata appears to be conspecific with the more northerly distributed C. vegae Theel. We also clarify the identity of C. lubrica Clark and further suggest that C. fisheri astigmata (recently revised to Pseudocnus) should be considered a junior synonym of C. lubrica. The recent description of C. pallida Kirkendale and Lambert as a species, distinct from C. miniata (Brandt), is also supported. The resultant phylogenetic trees are consistent with multiple origins of direct development within the Cucumariidae. Finally, we suggest that an in-depth phylogenetic analysis of sea cucumber families will require examination of additional, more slowly evolving, regions of the genome(s).

Reality monitoring failure in schizophrenia: the role of selective attention

Reality monitoring and selective attention have been repeatedly shown to be impaired in schizophrenia. Positive symptomatology has been found to be associated with deficits in both reality monitoring and selective attention. Therefore, a direct link between reality monitoring and selective attention was hypothesized. Thirty-two schizophrenic patients and 32 normal controls were administered the Stroop test as a measure of selective attention along with a test of three indices of reality monitoring, involving discrimination of: events vs. non-events, self- vs. externally-generated events, and oral vs. pictorial sources. A global memory test was administered for comparison. Results showed that schizophrenic patients were impaired in both reality monitoring and selective attention, and that these two were significantly correlated with each other in the schizophrenic sample. On the contrary, selective attention was not significantly correlated with memory efficiency in either group. Further, multiple regression analyses in schizophrenic patients showed that only selective attention contributed significantly to the variance in reality monitoring measures. Therefore, the results argue in favor of a specific role of a selective attention deficit in reality monitoring failure in schizophrenia.

PTL-1, a microtubule-associated protein with tau-like repeats from the nematode Caenorhabditis elegans

Tau, MAP2 and MAP4 are structural microtubule-associated proteins (MAPs) that promote the assembly and stability of microtubules. They share three or four imperfect tandem repeats of an amino acid motif, which is involved in the binding to microtubules. All sequences to data containing this motif are of mammalian origin. We report here the cloning and functional characterisation of a new member of this family of proteins from the nematode Caenorhabditis elegans. This protein exists as two isoforms of 413 and 453 amino acids with four or five tandem repeats that are 50% identical to the tau/MAP2/MAP4 repeats. Both isoforms bind to microtubules and promote microtubule assembly, with the five-repeat isoform being more effective at promoting assembly than the four-repeat isoform. When expressed in COS cells, the five-repeat isoform co-localises with microtubules and induces the formation of microtubule bundles, whereas its expression in Sf9 cells leads to the extension of long unipolar processes. In view of its length, amino acid sequence and functional characteristics, we have named this invertebrate structural MAP ‘Protein with Tau-Like Repeats’ (PTL-1). In C. elegans PTL-1 is expressed in two places known to require microtubule function. It is first seen in the embryonic epidermis, when circumferentially oriented microtubules help to distribute forces generated during elongation. Later, it is found in mechanosensory neurons which contain unusual 15 protofilament microtubules required for the response to touch. These findings indicate that MAPs of the tau/MAP2/MAP4 family are found throughout much of the animal kingdom, where they may play a role in specialised processes requiring microtubules.

Effects of fumonisin B1 and (hydrolyzed) fumonisin backbone AP1 on membranes: a spin-label study

Electron spin resonance (ESR) spectroscopy and spin label techniques have been used to study the effects of fumonisin B1 (FB1) and hydrolyzed fumonisin backbone (AP1) on the structural and dynamic properties of phosphatidylcholine membranes at the molecular level. Multilamellar liposomes consisting of dimyristoylphosphatidylcholine (DMPC) and egg yolk phosphatidylcholine (EYPC) were used. Six different nitroxide spin labels were used to determine what effects FB1 may impart on the ordering and mobility of lipids in membranes. The experimental results disclose the following: (1) In the fluid phase membrane, FB1 significantly increases the fluidities of n-doxylstearic acid (SA) spin labels (SL) attached to carbons 5 and 7, which disorders the alkyl chains and perturbs the surface region of the bilayer; by comparison, minimal effects were detected near the center of the bilayer. (2) In the gel phase, FB1 and AP1 imparts marked rigidifying effects on membrane fluidity, which enlarges the change in ordering on the phase transition even further. (3) FB1 also restricts the mobility of the (rigid) cholestane spin label. (4) A reduction in mobility of the tempo-stearate spin label suggests that the tricarballylic acid (TCA) moieties of FB1 might mimic the structure of polar headgroups in phospholipids. The present results may provide additional mechanisms to elucidate the toxicological activities of the fumonisins.

Assembly of microtubule-associated protein tau into Alzheimer-like filaments induced by sulphated glycosaminoglycans

The paired helical filament (PHF) is the major component of the neurofibrillary deposits that form a defining neuropathological characteristic of Alzheimer's disease. PHFs are composed of microtubule-associated protein tau, in a hyperphosphorylated state. Hyperphosphorylation of tau results in its inability to bind to microtubules and is believed to precede PHF assembly. However, it is unclear whether hyperphosphorylation of tau is either necessary or sufficient for PHF formation. Here we show that non-phosphorylated recombinant tau isoforms with three microtubule-binding repeats form paired helical-like filaments under physiological conditions in vitro, when incubated with sulphated glycosaminoglycans such as heparin or heparan sulphate. Furthermore, heparin prevents tau from binding to microtubules and promotes microtubule disassembly. Finally, we show that heparan sulphate and hyperphosphorylated tau coexist in nerve cells of the Alzheimer's disease brain at the earliest known stages of neurofibrillary pathology. These findings, with previous studies which show that heparin stimulates tau phosphorylation by a number of protein kinases, indicate that sulphated glycosaminoglycans may be a key factor in the formation of the neurofibrillary lesions of Alzheimer's disease.

Roles of prostaglandins and nitric oxide in the effect of endothelin-1 on renal hemodynamics

It is known that endothelin-1 stimulates the release of nitric oxide and prostaglandins in various vascular beds. We designed the present study to analyze the roles of prostaglandins and nitric oxide in the effect of endothelin-1 on the regulation of renal hemodynamics and renin release. We used N omega-nitro-L-arginine methyl ester (L-NAME) and meclofenamic acid to inhibit the production of nitric oxide and prostaglandins, respectively. With a nonfiltering kidney model, renal blood flow was reduced 21% in dogs treated with L-NAME and 18% in dogs treated with meclofenamic acid. Inhibition of nitric oxide and prostaglandins, however, produced opposite effects on estimated glomerular hydraulic pressure: L-NAME increased glomerular hydraulic pressure from 63.1 +/- 0.9 to 64.6 +/- 1.3 mm Hg (P < .01), and meclofenamic acid reduced glomerular hydraulic pressure from 63.3 +/- 1.4 to 59.8 +/- 1.6 mm Hg (P < .01). Endothelin-1 infusion produced a dose-dependent reduction in renal blood flow after blockade of nitric oxide and prostaglandins. The responses of glomerular hydraulic pressure were different in the two groups during endothelin-1 infusion. Endothelin-1 progressively reduced glomerular hydraulic pressure in a dose-dependent fashion in the meclofenamic acid group. However, endothelin-1 slightly increased glomerular hydraulic pressure until the infusion rate reached 5.0 ng/kg per minute. At that rate, endothelin-1 reduced glomerular hydraulic pressure from 63.3 +/- 1.4 to 47.0 +/- 1.4 mm Hg in the meclofenamic acid group (P < .01), a more than 25% reduction, whereas at the same dose, endothelin-1 reduced glomerular hydraulic pressure only less than 2% in the L-NAME group. In addition, blockade of nitric oxide and prostaglandins did not alter the inhibitory effect of endothelin-1 on renin release in the non-filtering kidney. Therefore, the present study demonstrates that the release of nitric oxide and prostaglandins might modulate the effects of endothelin-1 on the renal circulation. The present findings suggest that the differential vasoconstrictive effects of endothelin-1 on preglomerular and postglomerular vessels are associated with its stimulation of nitric oxide and prostaglandin production.

Atropine Metabolism by Pseudomonas sp. Strain AT3: Evidence for Nortropine as an Intermediate in Tropine Breakdown and Reactions Leading to Succinate

Pseudomonas strain AT3, isolated by elective culture with atropine, hydrolyzed atropine and grew diauxically, first on the tropic acid and then on the tropine. Tropine was also used as a sole carbon and energy source. The methyl group of tropine was eliminated as formaldehyde, and the nortropine thus formed was a precursor of 6-hydroxycyclohepta-1,4-dione. Ammonia was detected as a product of nitrogen elimination. 6-Hydroxycyclohepta-1,4-dione was oxidized to cyclohepta-1,3,5-trione by an induced NAD(sup+)-specific dehydrogenase. Although cyclohepta-1,3,5-trione is a (beta)-diketone with two potential hydrolytic cleavage sites, an induced hydrolase was specific for one of these sites, with 4,6-dioxoheptanoate as the only hydrolysis product. Unlike the alternative cleavage product (3,6-dioxoheptanoate), this compound is also a (beta)-diketone, and a second hydrolytic cleavage formed succinate and acetone. Although Pseudomonas strain AT3 was not capable of growth with acetone, the compound was not detected in the culture medium and may have been lost to the atmosphere. Exhaustive experimentation with a wide range of conditions did not result in detection of the enzymes required for cleavage of the carbon-nitrogen bonds leading to the formation of nortropine and 6-hydroxycyclohepta-1,4-dione.

Effects of fumonisin B1 on oxygen transport in membranes

Electron spin resonance (ESR) spin-label oximetry has been used to study the effects of fumonisin B1 (FB1), a sphingoid-like mycotoxin, on oxygen transport in phosphatidylcholine (PC) bilayers. Moreover, the use of spin labels attached to different carbons of fatty acids makes it possible to do structural and oximetric determinations with the same test sample. Specifically, the incorporation of 10 mol% FB1 increased the oxygen transport properties of both saturated and unsaturated membranes at 37 degrees C by ca. 30% and decreased the ordering of the hydrocarbon chains near the surface of the membranes; concomitantly, oxygen transport near the center of bilayers was diminished slightly, and the relative oxygen diffusion-concentration product profile curves were markedly flattened.

Phylogeography of an asexual marine clam complex, Lasaea, in the northeastern Pacific based on cytochrome oxidase III sequence variation

Northeastern Pacific populations of the intertidal marine clam Lasaea are exclusively composed of polyploid asexual clones that lack pelagic larval development. We investigated the phylogeographic structure of this clonal assemblage by assaying genetic divergence in 4 populations along 2000 km of the west coast of North America. In each population a 462-nt portion of the mitochondrial Cytochrome Oxidase III gene was amplified and sequenced for 30 individuals. A total of 21 haplotypes were detected and phylogenetic analyses resolved this variation into 5 main branches that differ in sequence composition by 8.9-14.5%. Two of the branches each encompass a single haplotype, the other 3 terminate in clades containing 3-11 lineages and within clade divergence ranges from 0.4 to 2.3%. Obvious geographic structuring was evident in that 19 of the 21 lineages were restricted in their distributions to single populations and 3 of the main phylogenetic branches were limited to specific marine biogeographic provinces. Two of the clades were encountered in multiple, geographically distant populations; however, the absence of shared haplotypes indicates that long distance gene flow is rare among these direct-developing populations. Northeastern Pacific Lasaea clones form a robust monophyletic grouping relative to other studied populations of the cosmopolitan genus. We estimate divergence times among northeastern Pacific clones to range from 3 to 6 myr. If the latest common ancestor of these exclusively asexual, genetically diverse, regionally monophyletic Lasaea lineages was also asexual, this represents a minimal age estimate for asexuality in the genus. The most plausible alternate hypothesis requires that at least 5 northeastern Pacific sexual parental species have recently become extinct.

Nursing Students' Perspectives: Experiences of Caring and Not-So-Caring Interactions with Faculty

The purpose of this study was to describe the meaning of baccalaureate nursing students' lived experience of caring and not-so-caring interactions with faculty. The research questions explored the phenomenon of being cared-for or not-cared-for by asking, "What does being cared-for by faculty mean to baccalaureate nursing students?" Students were also asked to describe not-so caring interactions with faculty. Seventeen baccalaureate nursing students at a private liberal arts college and 15 baccalaureate nursing students at a public university were interviewed. Transcripts of the tape-recorded interviews were analyzed using Giorgi's technique. After reflection upon the content of the interviews, significant statements were identified, meaning units were developed, and themes were extracted which were then abstracted into categories of Recognition, Connection, and Confirmation/Affirmation. Finally, general structural descriptions of phenomena of a caring and of a not-so-caring interaction were constructed. Implications for teaching, research, and practice are described.

The association between parental smoking and the diet quality of low-income children

OBJECTIVE

To assess the association between parental smoking and the diet quality of children residing in low-income housholds in the United States. MTHODS: Data from 515 low-income children (less than or equal to 185% of the poverty line), ages 2 to 17, who participated in the 1989 and 1990 United States Department of Agriculture Continuing Survey of Food Intakes of Individuals were examined. Diet quality was assessed by examining the average daily amount of nutrients consumed per 1000 kcal for protein, fiber, and 14 essential vitamins and minerals as well as total energy, percent of energy from total fat and saturated fat, and cholesterol and sodium intakes using the 3-day average of one 24-hour recall and 2 days of diet records. Parental smoking was categorized as four levels (nonsmoker; 1 to 10, 11 to 20, and more than 20) on the basis of the average number of cigarettes smoked per day by the sample child's parents. Analysis of covariance examined differences in the children's nutrient intake among the four smoking categories while controling for race, mother's age and occupation, child age, and sex.

RESULTS

Low-income children with parents who smoked (n = 235) were more likely to be white (P <.001), had younger mothers (P <.05) and were more likely to have mothers employed in blue-collar occupations (P <.001) than children whose parents were nonsmokers (N = 280). Children whose parents smoked more than 20 cigarettes per day had a higher level of energy from saturated fat, and children whose parents smoked 11 to 20 cigarettes per day had the highest cholesterol intakes in comparison with the rest of the sample. Parental smoking was also related to total fiber intake per 1000 kcal, with children of smokers having lower fiber intakes than children of nonsmokers.

CONCLUSIONS

On average, low-income children of smokers had a poorer diet quality than low-income children of nonsmokers, thus increasing their future risk of chronic disease.

Length variation, heteroplasmy and sequence divergence in the mitochondrial DNA of four species of sturgeon (Acipenser)

The extent of mtDNA length variation and heteroplasmy as well as DNA sequences of the control region and two tRNA genes were determined for four North American sturgeon species: Acipenser transmontanus, A. medirostris, A. fulvescens and A. oxyrhnychus. Across the Continental Divide, a division in the occurrence of length variation and heteroplasmy was observed that was concordant with species biogeography as well as with phylogenies inferred from restriction fragment length polymorphisms (RFLP) of whole mtDNA and pairwise comparisons of unique sequences of the control region. In all species, mtDNA length variation was due to repeated arrays of 78-82-bp sequences each containing a D-loop strand synthesis termination associated sequence (TAS). Individual repeats showed greater sequence conservation within individuals and species rather than between species, which is suggestive of concerted evolution. Differences in the frequencies of multiple copy genomes and heteroplasmy among the four species may be ascribed to differences in the rates of recurrent mutation. A mechanism that may offset the high rate of mutation for increased copy number is suggested on the basis that an increase in the number of functional TAS motifs might reduce the frequency of successfully initiated H-strand replications.

Detection and quantitation of melanoma cells in the circulation of patients

A method for the quantitation of tyrosinase mRNA in the bloodstream of melanoma patients has been developed by using competitive polymerase chain reaction (PCR) with a heterologous DNA (PCR MIMIC) as an internal standard. The method was validated by demonstration of similar amplification efficiencies for both molecules and by accurate quantitation of an artificial fourfold difference in the level of tyrosinase mRNA. The ratio of amplified target to amplified standard (At/As ratio) was determined for a range of melanoma patients who had previously tested positive for tyrosinase. Sequential samples were also analysed to examine the level of tyrosinase in individual patients over time. When tyrosinase levels in melanoma cell lines were compared for a constant amount of total RNA, or for a constant number of cells, tyrosinase mRNA was found to vary more than a thousand-fold between cell lines. Because of this, the At/As ratio of patients was compared with the At/As ratios obtained when 10-fold serial dilutions of cells from a control melanoma cell line (MM200) were added to 2 ml of packed blood. An 'MM200 equivalence' value was thus calculated, giving the equivalent number of MM200 cells in the bloodstream of melanoma patients. Prolonged follow-up will be needed to determine the prognostic significance of the detection and levels of tyrosinase mRNA in the bloodstream of melanoma patients.

Duration of embryonic diapause in the brush-tailed bettong, Bettongia penicillata (Potoroidae): effect of age of quiescent corpus luteum

It has been shown that changes to the frequency of sucking by the pouch young do not affect the time of reactivation of the quiescent corpus luteum and diapause embryo in Bettongia penicillata; these observations led to the suggestion that the corpus luteum may have an inherent maximum duration of quiescence. The aim of the present study was to investigate the effect of the age of the corpus luteum on the timing of its reactivation. Ovulation fails to occur post partum in female B. penicillata isolated from males, and the introduction of a male B. penicillata induces oestrus in females suckling a young in the pouch. Oestrus was induced from Day 23 of lactation to Day 76, in different females, and the corpus luteum became quiescent. All parturitions occurred between Day 95 and Day 103 of lactation (average, Day 98.8), at the time expected if the corpus luteum had been formed post partum. Duration of quiescence of the corpus luteum ranged from 60 days to 10 days, compared with 83.9 +/- 0.43 days in females that mated post partum. The results show that the age of the corpus luteum does not affect the timing of its redevelopment and release of the embryo from diapause near the end of the period of the young being suckled within the pouch.

Retardation of mentation in depressives: Posner's covert orientation of visual attention test

A double-key version of Posner's covert orientation of visual attention test, which involves shifting of preparation for response from one side to another, was administered to 32 depressives and 32 controls to evidence retardation of mentation in depressives and compare it to symptom-rating scales. Results showed depressives' overall response times to be consistently slower than controls. The time of maximal response preparation occurred later in depressives than in controls, showing clear evidence of pure retardation of mentation (not mixed with motor processes). This slowing of mentation was strongly correlated with observable psychomotor retardation but not with depressive severity.

Effects of hypoxemia on the electroretinogram in diabetics

PURPOSE

To identify any relationship between retinal dependence on oxygen and the presence or absence of retinopathy in a group of patients with the same duration of diabetes, based on the proposal that diabetic retinopathy results from long-term adaptation to the Crabtree effect, i.e., reduction of oxidative phosphorylation caused by increased intracellular glucose concentrations.

METHODS

Electroretinograms were recorded on 17 patients with insulin-dependent diabetes (of 15 to 17 years duration) and 10 healthy controls. Recordings were made under normal conditions and then after 4 min of hypoxemia (oxygen saturation, 80%). Retinopathy status was assessed from fundus photographs.

RESULTS

Electroretinogram b-wave amplitudes of seven patients without retinopathy were reduced to 69% by the hypoxemia compared to a reduction to 88% for 10 patients with retinopathy (p = 0.039).

CONCLUSIONS

The relative sensitivity to hypoxemia of patients without retinopathy suggests greater dependence on oxidative phosphorylation than in patients with retinopathy. The results appear to be consistent with the Crabtree effect hypothesis. Downregulation of tissue oxygen consumption by the Crabtree effect would lead to a reduction of retinal blood flow by autoregulation and to a reduced concentration of adenosine triphosphate in the retina.

Low-dose aspirin does not attenuate platelet aggregation or atherosclerosis in miniature swine but decreases production of aortic wall prostacyclin

The objectives of this study were to determine if, and at what dose, aspirin could attenuate atherosclerosis in hypercholesterolemic Yucatan miniature swine, and to determine the influence of aspirin on aortic wall prostacyclin production and platelet aggregation. 30 Yucatan miniature swine (age 3 months) were fed either regular diet (RD), atherogenic diet (AD), or AD plus one of four aspirin dosages (2,4,8, or 16 mg/kg/d) for 6 months. The extent of atherosclerotic lesions in the abdominal aorta and coronary arteries was evaluated by sudanophilic staining and histological grading using Stary's classification, respectively. Aortic wall production of prostacyclin (PGI2) and platelet aggregation were assessed. Lesions were similar among the AD groups (45.3 +/- 4.3%) and significantly higher than RD (1.4 +/- 0.4%). PGI2 production was significantly lower (p < 0.05) in all aspirin-treated groups. Platelet aggregation was not affected by treatment. It is concluded that the range of aspirin dosages (2-16 mg/kg/d) does not attenuate the development of atherosclerosis.

Psychometric characteristics of ideational retardation in depressives

In two studies we tested the assumption that slowing of ideation (the ideational counterpart of psychomotor retardation) reflects a dimension distinct from severity of depression. Specifically, we hypothesized that an objective measure of ideational retardation would be correlated with a psychomotor retardation rating scale but not with a depression severity rating scale. There was in-patients in Study 1 and 30 out-patients in Study 2; all satisfied DSM-III criteria for major depressive episode. Measurements of ideational retardation, and notably latency of response, were derived from patient responses to the Rorschach plates (Study 1) and to simplified non-figurative line drawings (Study 2). As expected, results showed that latencies of response were not significantly correlated with depression severity scores on the Montgomery and Asberg Depression Rating scale (r = .19 in Study 1, r = -.08 in Study 2), but were significantly correlated with the scores on the Salpétrière Retardation Rating Scale (subscale for observable items, SRRSo)(r = .71, p < .0005 in Study 1; r = .55, p < .005, in Study 2).

Blockade of C5a and C5b-9 generation inhibits leukocyte and platelet activation during extracorporeal circulation

Complement activation contributes to the systemic inflammatory response induced by cardiopulmonary bypass. At the cellular level, cardiopulmonary bypass activates leukocytes and platelets; however the contribution of early (3a) versus late (C5a, soluble C5b-9) complement components to this activation is unclear. We used a model of simulated extracorporeal circulation that activates complement (C3a, C5a, and C5b-9 formation), platelets (increased percentages of P-selectin-positive platelets and leukocyte-platelet conjugates), and neutrophils (upregulated CD11b expression). to specifically target complement activation in this model, we added a blocking mAb directed at the human C5 complement component and assessed its effect on complement and cellular activation. Compared with a control mAB, the anti-human C5 mAb profoundly inhibited C5a and soluble C5b-9 generation and serum complement hemolytic activity but had no effect on C3a generation. Additionally, the anti-human C5 mAb significantly inhibited neutrophil CD11b upregulation and abolished the increase in P-selectin-positive platelets and leukocyte-platelet conjugate formation compared to experiments performed with the control mAb. This suggests that the terminal components C5a and C5b-9, but not C3a, directly contribute to platelet and neutrophil activation during extracorporeal circulation. Furthermore, these data identify the C5 component as a site for therapeutic intervention in cardiopulmonary bypass.

Reduced parasympathetic control of heart rate in obese dogs

We investigated why resting heart rate is elevated in dogs fed a high saturated fat diet for 12.7 +/- 1.8 wk. Obese dogs exhibited elevated body weight (59%), blood pressure (14%), and heart rate (25%). Differences in resting heart rate (control, 58 +/- 5 beats/min; obese, 83 +/- 7 beats/min) were abolished after hexamethonium, indicating an autonomic mechanism. Hexamethonium also reduced blood pressure in obese (20 +/- 4 mmHg) but not control (9 +/- 6 mmHg) animals. Propranolol did not affect heart rate in either group, excluding a beta-adrenergic mechanism. Subsequent administration of atropine increased heart rate more in control than in obese dogs (110 +/- 9 vs. 57 +/- 11 beats/min). The sensitivity of the cardiac limb of the baroreflex (Oxford method) was reduced by 46% in the obese group, confirming impairment of the parasympathetic control of heart rate. The standard deviation of blood pressure measurements was normal when expressed as a percentage of the mean arterial blood pressure (control, 11.2 +/- 0.4%; obese, 11.2 +/- 0.5%). Our results indicate that the development of obesity in dogs fed a high saturated fat diet is accompanied by an attenuated resting and reflex parasympathetic control of heart rate.

Altered insulin secretory responses to glucose in subjects with a mutation in the MODY1 gene on chromosome 20

This study was undertaken to test the hypothesis that the diabetes susceptibility gene on chromosome 20q12 responsible for maturity-onset diabetes of the young (MODY) in a large kindred, the RW family, results in characteristic alterations in the dose-response relationships between plasma glucose concentration and insulin secretion rate (ISR) that differentiate this form of MODY from MODY in subjects with glucokinase mutations. Ten marker-positive subjects and six matched nondiabetic marker-negative subjects from the RW family received graded intravenous glucose infusions on two occasions separated by a 42-h continuous intravenous glucose infusion designed to prime the beta-cell to secrete more insulin in response to glucose. ISR was derived by deconvolution of peripheral C-peptide levels. Basal glucose and insulin levels were similar in marker-negative and marker-positive groups (5.3 +/- 0.2 vs. 5.0 +/- 0.2 mmol/l, P > 0.2, and 86.1 +/- 3.9 vs. 63.7 +/- 12.1 pmol/l, P > 0.1, respectively). However, the marker-positive subjects had defective insulin secretory responses to an increase in plasma glucose concentrations. Thus, as the glucose concentration was raised above 7 mmol/l, the slope of the curve relating glucose and ISR was significantly blunted in the marker-positive subjects (13 +/- 4 vs. 68 +/- 8 pmol.min-1.mmol-1 x 1, P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

The molecular phylogeny of five eastern north Pacific octopus species

The DNA sequence of a 612-nucleotide fragment of the mitochondrial cytochrome oxidase subunit III gene from five Octopus species has been determined. The COIII gene in these species shows an extreme bias against G in the DNA sense strand with a moderately low C composition. The bias against G and C severely restricts the codon usage in Octopus COIII genes. The aligned DNA sequences were subjected to distance, maximum-likelihood, and parsimony analyses to ascertain the phylogenetic relationship of the species. The results of all of the analyses were concordant. The analyses indicate that O. bimaculoides and O. bimaculatus are the least diverged of the species and fall into a separate clade from O. dolfleini and O. californicus, which are also closely related. O. rubescens is about equally removed from the other species, but parsimony, distance, maximum-likelihood, and logdet analyses suggest that it is more closely aligned with the O. bimaculoides/O. bimaculatus lineage.

Hypopituitarism in primary haemochromatosis; recovery after iron depletion

We report a case of primary haemochromatosis complicated by anterior hypopituitarism which recovered after aggressive venesection therapy. Reversal of anterior hypopituitarism in haemochromatosis following iron depletion has not been previously described.

Tropine dehydrogenase: purification, some properties and an evaluation of its role in the bacterial metabolism of tropine

Tropine dehydrogenase was induced by growth of Pseudomonas AT3 on atropine, tropine or tropinone. It was NADP(+)-dependent and gave no activity with NAD+. The enzyme was very unstable but a rapid purification procedure using affinity chromatography that gave highly purified enzyme was developed. The enzyme gave a single band on isoelectric focusing with an isoelectric point at approximately pH 4. The native enzyme had an M(r) of 58,000 by gel filtration and 28,000 by SDS/PAGE and therefore consists of two subunits of equal size. The enzyme displayed a narrow range of specificity and was active with tropine and nortropine but not with pseudotropine, pseudonortropine, or a number of related compounds. The apparent Kms were 6.06 microM for tropine and 73.4 microM for nortropine with the specificity constant (Vmax/Km) for tropine 7.8 times that for pseudotropine. The apparent Km for NADP+ was 48 microM. The deuterium of [3-2H]tropine and [3-2H]pseudotropine was retained when these compounds were converted into 6-hydroxycyclohepta-1,4-dione, an intermediate in tropine catabolism, showing that the tropine dehydrogenase, although induced by growth on tropine, is not involved in the catabolic pathway for this compound. 6-Hydroxycyclohepta-1,4-dione was also implicated as an intermediate in the pathways for pseudotropine and tropinone catabolism.

A critique of instruments and methods to detect, diagnose, and rate delirium

This document reviews existing instruments for evaluation of delirium. Instruments have been grouped into four categories: tests that screen for cognitive impairment, delirium diagnostic instruments, delirium-specific numerical rating scales, and laboratory and paraclinical exams. Analysis of instruments was based on comparison of their psychometric properties as well as subjective judgment. Guidelines are suggested for choosing the appropriate instrument according to the type of clinical evaluation or delirium research envisaged. Important factors in choosing an instrument, besides the appropriateness of its psychometric characteristics, include administration time constraints, level of rater expertise, and patient capabilities. By familiarizing investigators with the variety of evaluation instruments available, this work should permit more appropriate instrument selection in future studies on delirium.

Nerve extracts and substance P activate the phosphatidylinositol signaling pathway and mitogenesis in newt forelimb regenerates

We investigated the inositol phospholipid transmembrane signaling pathway as a possible mediator of neurotrophic (mitogenic) signals in the newt limb regeneration blastema. Blastema mesoderm tissues were prelabeled with myo-[3H]inositol, treated with 10 mM LiCl and then exposed to substance P or to extracts of spinal ganglia, brain, or spinal cord. Stimulation with substance P resulted in a rapid dose-dependent reduction of [3H]phosphatidylinositol 4,5-bisphosphate and [3H]phosphatidylinositol 4-phosphate, correlated with a rapid accumulation of inositol 1,4,5-triphosphate. This effect was inhibited when the blastema tissue was treated with neomycin, a known inhibitor of inositol phospholipid turnover. In addition, substance P stimulated the incorporation of [3H]thymidine into DNA of blastema mesoderm cells, and this effect was also suppressed by neomycin, at a dose corresponding to that required to inhibit inositol phosphate accumulation. Extracts of neural tissues, especially spinal ganglia, induced the formation of inositol phosphates and extract activity was attenuated following treatment with heat or trypsin. These findings suggest a role for mitogen-activated inositol phospholipid signaling, initiating events that ultimately lead to cell proliferation.

Sex determination. Turning on sex

The orphan nuclear receptor, steroidogenic factor 1, is central to the differentiation of male and female mammalian gonads. It controls the fate of the initially bipotential gonad as well as later male-specific functions.

Hypoglycemia counterregulation in elderly humans: relationship to glucose levels

This study was designed to define the effect of human aging on hypoglycemia counterregulatory mechanisms. A hyperinsulinemic (2 mU.kg-1.min-1) glucose clamp procedure was used to control glucose and insulin levels during stepwise lowering of plasma glucose. Counterregulatory hormones, hepatic glucose production (HGP), glucose utilization, and symptoms of hypoglycemia were studied in 13 healthy young [age 24 +/- 1 (SE) yr] and 11 healthy old (age 65 +/- 1 yr) nondiabetic volunteers on two occasions: 1) at matched euglycemia and 70 and 60 mg/dl (study 1) and 2) at matched euglycemia and 60 and 50 mg/dl (study 2). The old had consistently lower epinephrine (P < 0.005), glucagon (P < 0.02), cortisol (P < 0.05), and pancreatic polypeptide (P < 0.02) responses at the 60-mg/dl glucose step in study 1. However, these differences were no longer detectable at the more severe hypoglycemic stimulus of 50 mg/dl in study 2. A consistent increase in HGP occurred in both groups only at the 50-mg/dl glucose step (study 2) and was not different between young and old. There were also no differences in symptom responses between young and old. In summary, we found that elderly individuals have a subtle impairment of the glucose counterregulatory response during moderate hypoglycemia, but this impairment is no longer detectable during more severe hypoglycemia.

MIC2R: a transcribed MIC2-related sequence associated with a CpG island in the human pseudoautosomal region

Sequences related to exons 1, 4 and 5 of the human pseudoautosomal gene MIC2 have been detected on the X and Y chromosomes of humans and other primate species. Isolation of these sequences has defined a new transcribed locus, MIC2R (MIC2-related) which is associated with the second most proximal CpG-rich island in the human pseudoautosomal region. Genomic sequences from the MIC2R locus show that it is composed of a single sequence related to exon 1 and at least four tandem copies of sequences related to exons 4 and 5 of MIC2. Comparison of the four exon 4- and 5-related sequences suggest that they are the result of sequential duplication of a 2.8 kb region during evolution. Transcripts from the MIC2R locus have been detected in all tissues analysed and a number of different transcripts appear to be generated by alternative RNA splicing. However, as none of the transcripts analysed to date contain a significant open reading frame, the function of the MIC2R locus remains unknown.

Expression of the co-stimulatory molecule B7 on melanoma cells

The induction of T-cell responses against tumor cells is believed to depend on both recognition of antigen and receipt of co-stimulatory signals from interaction of ligands such as B7 with its receptors CD28 or CTLA-4 on T cells. In the present study the expression of B7 on cultured human melanoma cells was studied at the mRNA level by reverse PCR analysis and surface expression by flow cytometric analysis with monoclonal antibodies (MAbs). PCR analysis revealed mRNA for B7 in 3 of 6 (50%) cultured primary melanoma and 8 of 19 (42%) cultures of metastatic melanoma. Analysis of B7 expression by flow cytometry using the BB1 MAb revealed low levels of expression in 3 of 10 melanoma that had mRNA for B7. In 2 of the latter (but not 4 other PCR+ lines) expression could be increased by culture in GM-CSF, IL-2, IFN-gamma and IFN-alpha 2. Our results indicate that although mRNA for B7 is present in 40-50% of melanoma cell lines, expression at the protein level is at low or undetectable levels in the majority of the cell lines. Expression of B7 protein was also not detected in studies on tissue sections from 11 primary and 9 metastatic melanomas.

Faecal dry weight and potassium are related to faecal sodium and plasma aldosterone in rats chronically fed on varying amounts of sodium or potassium chlorides

Recent studies have shown that faecal residue (dry weight) and Na and K increase with increasing levels of dietary fibre, an effect which may be related to unstirred layers that slow absorption and the flow rate of chyme through the gastrointestinal tract. Salts of Na are the primary osmotic components of chyme and influence both retention of fluid in the bowel and transit of fluid from the small to the large intestine. The present study examines the chronic effects of dietary Na and K intake on faecal Na, K and residue excretion. Male Sprague-Dawley rats were given 12-13 g feed/d (control (g/kg): Na 4, K 8.5) for 1 week, followed by a 4-week period where Na or K intake was altered (0.01-3 times control levels). These diets altered chronic (> 1 week) faecal residue excretion and affected Na and K excretion by 8-, 310- and 2100-fold respectively. Low dietary Na reduced faecal Na and residue; K excretion was doubled during week 1, but fell over weeks 2-4 despite a 4-5-fold increase in plasma aldosterone. Chronic high dietary Na increased faecal Na, residue and K despite a 60% decrease in plasma aldosterone. Chronic low dietary K decreased faecal Na, K and residue and plasma aldosterone. Chronic high dietary K did not alter faecal Na and K despite increased faecal residue and a 4-5-fold increase in plasma aldosterone. Faecal water was unchanged by diet, paralleling changes in faecal residue. Analyses of the results provide systematic models of chronic regulation of faecal Na, K and residue excretions. When plasma aldosterone is low (< 160 ng/l), weekly faecal residue excretion is equal to 3.6 g (fibre intake was 2.6-2.7 g/week)+2.6 g/mmol Na, and K excretion is equal to 0.55 mmol/mmol Na. When plasma aldosterone is high (> 1500 ng/l) weekly faecal residue excretion is equal to 2.3 g + 2.6 g/mmol Na, and K excretion is equal to 0.7 mmol/week + 0.55 mmol/mmol Na.

Experimental evidence for two dimensions of cognitive disorders in depressives

Three neuropsychological tests (Rey's auditory verbal learning test, word fluency and signal detection test for words) were administered to 36 depressed patients (medicated and non-medicated) and 26 controls and compared to scale scores for depression severity and psychomotor retardation to examine how retardation was related to cognitive performance. As expected, compared to controls depressives exhibited non-specific "cognitive inefficiency", that is, consistently deficient performance in all cognitive tasks. Results on all three tests were correlated with one other and with depressive severity (measured by the Montgomery & Asberg Depression Rating Scale, MADRS). One notable exception, however, was the score for commission errors ("false alarms") in the signal detection test, which correlated negatively with psychomotor retardation (measured by a subscale of the Salpétrière Retardation Rating Scale, SRRS) but not at all with depressive severity. Lack of commission errors thus seemed to index a dimension of retardation of ideation that seemed distinct from the non-specific cognitive inefficiency dimension. Conversely, omission errors in the same test strongly correlated with the other two cognitive tests and with depressive severity but not with psychomotor retardation. Cognitive performance in depressives might thus be explainable in terms of two overlapping dimensions of depressive pathology (global cognitive impairment vs. specific effect of retardation). Further studies with non-medicated patients are needed to determine to what extent these findings may be due to medication effects.

Mini-dose (1-microCi) 14C-urea breath test for the detection of Helicobacter pylori

OBJECTIVES

To develop and evaluate a mini-dose (1-microCi) 14C-urea breath test (UBT), using a simplified protocol.

METHODS

Fasting patients (n = 95) were given a drink of 1 microCi (37 kBq) of 14C-urea. Samples of breath carbon dioxide (2 mmol) were collected at 10, 20, and 30 min later by trapping in hyamine solution; 14C activity was measured by liquid scintillation counting. Results were expressed as "CO2 recovery," i.e., [(% of administered dose recovered/mmol CO2 trapped) x body weight (kg)]. Reproducibility of the test was assessed by repeat studies on two consecutive days in 11 volunteers. All breath test results were compared with culture for Helicobacter pylori. In 27 patients, results also were compared with 13C-urea breath test (European protocol).

RESULTS

Using receiver operator characteristic (ROC) analysis, we selected a cut-off value of 0.55 at 20 min to separate those positive and negative for H. pylori. Sensitivity and specificity were 98% and 87%, respectively. Among four patients with negative culture but positive 14C-breath tests, three had evidence of infection by serology or 13C-UBT. Assuming that these three were genuinely positive, the recalculated specificity improved to 97%, sensitivity remaining at 98%. The reproducibility of the test was good, with only a minor day-to-day variation. Concordance with the 13C-UBT was excellent: there was 100% agreement in the diagnostic classification of all 27 patients (19 positive, eight negative).

CONCLUSIONS

The mini-dose 14C-urea breath test has a high diagnostic accuracy (sensitivity 98%, specificity 97%) with minimal radiation exposure. It is simple, rapid, and convenient for a busy general hospital.

Anticholinergic premedication for fibreoptic bronchoscopy

Atropine is routinely used as part of the premedication regimen for fibreoptic bronchoscopy. This study was performed, firstly, to evaluate the effect of anticholinergic agents on the ease of bronchoscopy, haemodynamic parameters and patient comfort during the procedure; and secondly, to compare atropine with glycopyrrolate, a newer acetylcholine antagonist which is claimed to cause less tachycardia and sedation, whilst suppressing salivation more effectively. One hundred and ninety consecutive patients were randomly allocated to three treatment groups: diazepam 5 mg; diazepam 5 mg + atropine 600 micrograms; and diazepam 5 mg + glycopyrrolate 300 micrograms. Diazepam was given orally one hour before bronchoscopy, and glycopyrrolate/atropine intramuscularly 30 min before bronchoscopy. All patients received thalamonal intravenously, lignocaine gel into one nostril, and lignocaine by transtracheal injection just prior to the procedure. The incidence of bronchoscopy related haemodynamic problems was similar in all three groups. Troublesome coughing, as observed by the operator, was less frequent with glycopyrrolate (control 51%, atropine 42%, glycopyrrolate 30%), as was patient movement (40%, 32%, 19%, respectively). Uncomfortable dryness of the mouth was most common with glycopyrrolate (37%, 32%, 66%, respectively), but overall assessment of discomfort, and the number of patients who would agree to a repeat bronchoscopy (73%, 76%, 70%, respectively) were very similar in all three groups. In conclusion, the differences between the three groups were slight. Glycopyrrolate made the bronchoscopy slightly easier for the operator because of significantly improved cough and movement suppression, though atropine was marginally preferable in terms of patient comfort.

Assembly of Alzheimer-like filaments from full-length tau protein

The principal fibrous component of neurofibrillary pathology in Alzheimer's disease, the paired helical filament, is formed from hyperphosphorylated microtubule-associated protein tau. Here we show that recombinant tau protein either in a non-phosphorylated state or following phosphorylation with brain extract can be assembled in vitro into filaments resembling those seen in Alzheimer's disease.

Surfactant protein A-directed toxin gene kills lung cancer cells in vitro

Human surfactant protein A (SPA) expression is considered a marker of respiratory epithelial differentiation. Non-small cell lung cancers (NSCLC) are respiratory epithelial derivatives, and it was previously shown that a minority of these cancers expressed SPA, presumably a consequence of their respiratory epithelial origin. In the studies reported here, SPA-I gene transcriptional regulatory sequences were localized to a 2.75-kb genomic 5'-flanking region fragment obtained by screening a human genomic library. The 2.75-kb fragment was used to direct a luciferase coding sequence transcriptionally within a plasmid construct. In plasmid transduction experiments, the SPA-directed luciferase plasmid produced significant luciferase activity in the SPA-expressing NSCLC cell line, H441, but only background levels in the non-SPA-expressing A549 cells. Because Northern blot analysis of resected NSCLC showed that the majority expressed SPA, an SPA-transcriptional targeting strategy was investigated using chimeric toxin genes comprising the coding sequence for herpes simplex virus thymidine kinase (HSV-TK) under transcriptional control of SPA or SV40 regulatory sequences. As expected, transduction of the constitutive, SV40-directed plasmid followed by ganciclovir treatment reduced numbers of both the A549 and H441 cells. In contrast, the SPA-directed plasmid reduced only the SPA-expressing H441 cells and had no significant effect on the A549 cells. The results of these in vivo experiments suggest the concept of transcriptionally directing toxin genes with SPA can produce targeted toxicity in NSCLC.