Philopatry of male marine turtles inferred from mitochondrial DNA markers

Recent studies of mitochondrial DNA (mtDNA) variation among marine turtle populations are consistent with the hypothesis that females return to beaches in their natal region to nest as adults. In contrast, less is known about breeding migrations of male marine turtles and whether they too are philopatric to natal regions. Studies of geographic structuring of restriction fragment and microsatellite polymorphisms at anonymous nuclear loci in green turtle (Chelonia mydas) populations indicate that nuclear gene flow is higher than estimates from mtDNA analyses. Regional populations from the northern and southern Great Barrier Reef were distinct for mtDNA but indistinguishable at nuclear loci, whereas the Gulf of Carpentaria (northern Australia) population was distinct for both types of marker. To assess whether this result was due to reduced philopatry of males across the Great Barrier Reef, we determined the mtDNA haplotypes of breeding males at courtship areas for comparison with breeding females from the same three locations. We used a PCR-restriction fragment length polymorphism approach to determine control region haplotypes and designed mismatch primers for the identification of specific haplotypes. The mtDNA haplotype frequencies were not significantly different between males and females at any of the three areas and estimates of Fst among the regions were similar for males and females (Fst = 0.78 and 0.73, respectively). We conclude that breeding males, like females, are philopatric to courtship areas within their natal region. Nuclear gene flow between populations is most likely occurring through matings during migrations of both males and females through nonnatal courtship areas.

Effects of alfentanil on cerebral haemodynamics in an experimental model of traumatic brain injury

Alfentanil is reported to increase intracranial pressure (ICP) after neurotrauma. A direct cerebral vasodilator effect has been postulated. We studied 17 Sprague-Dawley rats allocated to one of three groups. Animals were anaesthetized and their lungs ventilated, and arterial pressure, ICP and/or regional cerebral blood flow (CBF) measurements were undertaken. Group 1 (n = 6) received a severe closed head injury while group 2 (n = 5) received no injury. ICP and mean arterial pressure (MAP) were measured before, during and after rapid infusion of alfentanil 250, 500 and 750 micrograms kg-1. CBF was measured by hydrogen clearance before rapid infusions and at 30-min intervals after starting a subsequent slow infusion of alfentanil 500 micrograms kg-1 h-1. Group 3 (n = 6) underwent CBF measurement only, for comparison with those of groups 1 and 2. They received an injury but no alfentanil. ICP or MAP values did not differ significantly between groups 1 and 2. Rapid i.v. doses of alfentanil produced increases in ICP and reductions in MAP. ICP changes were consistent with a drug effect (P < 0.001) but were small. Reductions in MAP were significant (P < 0.05) and preceded changes in ICP. CBF values were similar and unaffected by slow alfentanil infusion in groups 1 and 2, and did not differ significantly between groups 1 and 3. We conclude that alfentanil did not appear to exert a direct effect on the cerebral circulation. Changes in ICP after rapid infusion were secondary to reductions in SAP. Slow infusion did not cause such changes.

Effect of surgical experience on results of esophagectomy for esophageal carcinoma

BACKGROUND

Esophagectomy for esophageal cancer is associated with substantial operative morbidity and mortality. The effect of surgical experience on results of esophagectomy has received little attention in the medical literature.

METHODS

A retrospective review of esophagectomies for cancer was done.

RESULTS

Seventy-four patients underwent esophagectomy by 20 different surgeons. Three surgeons performed 6 or more esophagectomies per year ("frequent" surgeons), whereas the other 17 surgeons performed 5 or fewer esophagectomies per year ("occasional" surgeons). Forty-two patients were operated on by frequent surgeons. There were 3 (7%) anastomotic leaks and no deaths. In 32 patients operated on by occasional surgeons, there were 7 (22%) anastomotic leaks and 7 (22%) operative deaths. The anastomotic leak rates were not significantly different (P < .07), but frequent surgeons had a significantly lower operative mortality (P < .0014).

CONCLUSIONS

Esophagectomy for esophageal cancer should be performed by experienced esophageal surgeons with sufficient yearly volume of procedures to maintain competence.

Electrokinetic Behavior of Fluoride Salts as Explained from Water Structure Considerations

Unlike the other silver halides, silver fluoride is positively charged in its saturated solution as determined by nonequilibrium electrophoresis measurements. In the absence of surface hydrolysis reactions, other fluoride salts (LiF, CaF2 , and MgF2 ) also are positively charged in their saturated solutions. Furthermore, the electrokinetic behavior of these fluoride salts is rather insensitive to the fluoride ion activity in neutral or acidic solutions, and reversal of the sign of the surface charge by fluoride addition is not possible. Based on FTIR transmission spectra to describe the water structure of ionic solutions, in situ FTIR/internal reflection spectroscopy (FTIR/IRS) has been used to spectroscopically characterize interfacial water at fluoride salt surfaces. The experimental spectra were examined by consideration of the O-H stretching region (3000-3800 cm-1 ) associated with the vibrational spectra of interfacial water. These results reveal a unique hydration state for fluorides and explain the anomalous electrokinetic behavior of fluoride salts such as LiF, CaF2 , and MgF2 , which show an unexpected insensitivity to the fluoride ion concentration in solution. It appears that this insensitivity is due to the formation of strong hydrogen bonding of the fluoride ions with water molecules. This hydration state prevents the accommodation of excess fluoride ions at surface lattice sites and accounts for the observed electrokinetic behavior.

Effect of surgical experience on results of esophagectomy for esophageal carcinoma

BACKGROUND

Esophagectomy for esophageal cancer is associated with substantial operative morbidity and mortality. The effect of surgical experience on results of esophagectomy has received little attention in the medical literature.

METHODS

A retrospective review of esophagectomies for cancer was done.

RESULTS

Seventy-four patients underwent esophagectomy by 20 different surgeons. Three surgeons performed 6 or more esophagectomies per year ("frequent" surgeons), whereas the other 17 surgeons performed 5 or fewer esophagectomies per year ("occasional" surgeons). Forty-two patients were operated on by frequent surgeons. There were 3 (7%) anastomotic leaks and no deaths. In 32 patients operated on by occasional surgeons, there were 7 (22%) anastomotic leaks and 7 (22%) operative deaths. The anastomotic leak rates were not significantly different (P < .07), but frequent surgeons had a significantly lower operative mortality (P < .0014).

CONCLUSIONS

Esophagectomy for esophageal cancer should be performed by experienced esophageal surgeons with sufficient yearly volume of procedures to maintain competence.

Head Blight Gradients Caused by Gibberella zeae from Area Sources of Inoculum in Wheat Field Plots

ABSTRACT The spread of Fusarium head blight of wheat from a small area inoculum source was examined in wheat plots (100, 625, or 2,500 m(2)) inoculated in the center with Gibberella zeae-colonized corn kernels or macro-conidia sprayed on heads at anthesis. With the first inoculation method, disease foci were produced from ascospores released from perithecia formed on inoculated kernels. With the second inoculation method, disease foci were produced by macroconidia directly applied to the heads. Some plots were misted during anthesis. Plots were divided into grids, and disease incidence on spikelets and seeds was assessed at the grid intersections. Isopath contour maps were constructed using an interpolation procedure based on a weighted least squares method. Disease gradients were constructed from the isopath contours in the direction parallel to average nightly wind vectors using an exponential model. This study was conducted over a 3-year period at two sites: one in Quebec and one in Ontario. Both inoculation methods resulted in a discrete, primary focus of head blight in each plot, with one or two smaller secondary foci in some plots. The highest incidence of disease on spikelets or seed was commonly displaced somewhat from the inoculum source, usually downwind. The gradient slopes of seed and spikelet infection ranged from -0.10 to -0.43 m(1) in plots with ascospore inoculum and from -0.48 to -0.79 m(1) in plots inoculated with macroconidia. Seed infection declined to 10% of the maximum within 5 to 22 m from the focal center in asco-spore-inoculated plots, and within 5 m in a macroconidia-inoculated plot. Gradients were usually steeper upwind compared with downwind of the inoculum source. In misted plots, incidence of disease was higher and more diffuse than in nonirrigated plots. Based on gradients and dispersal patterns, disease foci in plots inoculated with G. zeae-colonized corn kernels probably arose from airborne ascospores rather than from splash-borne macroconidia and were the result of infection events that occurred over a short period of time. Comparison of conidial- and ascospore-derived disease gradients indicated a lack of secondary infection, confirming that Fusarium head blight is primarily a monocyclic disease.

Absence of a synergistic effect between fumonisin B1 and N-nitrosomethylbenzylamine in the induction of oesophageal papillomas in the rat

Fumonisins and N-nitrosamines (NNO) are suggested risk factors in the development of human oesophageal cancer; exposure to both occurs in high risk populations in Africa and People's Republic of China. The hypothesis that the two would interact in oesophageal carcinogenesis was therefore tested by treating male rats with the known oesophageal carcinogen N-methylbenzylnitrosamine (NMBA), and fumonisin B1 (FB1). The treatment groups were: Group 1, NMBA (2.5 mg/kg) intraperitoneally twice per week from week 2 to 4 inclusive; Group 2, as for group 1 but in addition FB1 (5 mg/kg) daily from weeks 1 to 5 inclusive by gavage; Group 3, FB1 (5 mg/kg) alone daily from weeks 1 to 5 inclusive by gavage, and Group 4, vehicle treatment from week 1 to 5 inclusive. Two of 12 animals in group 1 developed oesophageal papillomas and a further two had oesophageal dysplasia. Data were similar in group 2, animals receiving both NMBA and FB1, with one of 12 animals having papillomas and three of 12 with dysplasia. Sphingolipid biosynthesis was affected in the kidney and slightly in the liver after fumonisin treatment but not in the oesophagus or lung as determined by sphinganine:sphingosine ratios in urine and tissues. These data show that there is no synergistic interaction between NMBA and FB1 in the rat oesophagus when the two compounds are administered together. It is nevertheless important to examine other experimental models and treatment protocols which may be more relevant to the human situation and also to pursue epidemiological investigations of the role of fumonisins in oesophageal cancer.

The use of ergosterol to measure exposure to fungal propagules in indoor air

This report concerns the development of a method for the measurement of ergosterol in indoor air as a determinant of fungal exposure. Ergosterol was determined in spores of 11 species of Aspergillus, Penicillium, and Cladosporium selected from the most common molds in 400 homes in Ontario. Spore ergosterol content was about 1 microgram/mg, which is the range reported for mycelia, and varied by about 25% for the species tested. Ergosterol was determined in bedroom air samples taken in the winter in homes in southern Ontario. The median ergosterol value corresponded to a total concentration of fungal spores on the order of 10 to 10(2) per m3, in the range for other studies where total and viable propagules were determined by other methods. The sampling of air for ergosterol is a robust method for assessing fungal biomass in air, but provides no information on the species present.

Measurement of Interaction Forces between Silica and alpha-Alumina by Atomic Force Microscopy

Interaction forces between a silica sphere and an alpha-alumina substrate at various pH values were measured by atomic force microscopy (AFM). As expected, at pH values of 10.8 and 10.2 when the surfaces are similarly charged, a repulsive force was observed. On the other hand, at pH values of 5.5, 6.4, and 8.6 when the surfaces are oppositely charged, attractive forces were observed. Experimental force vs separation distance curves were found to be in good agreement with theoretical predictions based on electrostatic and van der Waals interactions. Interestingly, when the force/radius values at a particular separation distance were plotted against pH, the transition from an attractive to a repulsive force occurred at pH 9.3, which is very close to the point of zero charge (pzc) of alpha-alumina as determined from electrophoresis experiments. These results suggest that AFM force measurements can be used to estimate the pzc of materials. This method may be of particular significance for soluble salt minerals where conventional electrophoretic measurements are not possible at high ionic strengths. Finally, results from transmittance studies further confirmed the interaction between silica and alpha alumina particles in suspensions at various pH values as would be expected based on the results from atomic force microscopy measurements.

The CBFbeta subunit is essential for CBFalpha2 (AML1) function in vivo

The CBFbeta subunit is the non-DNA-binding subunit of the heterodimeric core-binding factor (CBF). CBFbeta associates with DNA-binding CBFalpha subunits and increases their affinity for DNA. Genes encoding the CBFbeta subunit (CBFB) and one of the CBFalpha subunits (CBFA2, otherwise known as AML1) are the most frequent targets of chromosomal translocations in acute leukemias in humans. We and others previously demonstrated that homozygous disruption of the mouse Cbfa2 (AML1) gene results in embryonic lethality at midgestation due to hemorrhaging in the central nervous system and blocks fetal liver hematopoiesis. Here we demonstrate that homozygous mutation of the Cbfb gene results in the same phenotype. Our results demonstrate that the CBFbeta subunit is required for CBFalpha2 function in vivo.

Monitoring weight drop velocity and foam stiffness as an aid to quality control of a rodent model of impact acceleration neurotrauma

Since the publication by Marmarou of a new rodent model of head injury, an increasing number of centres are adopting the model for use in a variety of paradigms. We report on two simple methods we have applied which allows us to monitor weight drop velocity and foam stiffness, both of which are critical factors for producing repeatable closed head injury with this model. We hope the application of these methods will assist in the standardisation of this model between centres.

New insights into the mammalian circadian clock

The focus of this review is recent studies of the mammalian circadian pacemaker in the suprachiasmatic nucleus (SCN) of the hypothalamus. The anatomy of the SCN and its major afferents from the retina, raphe, and intergeniculate leaflet (IGL) of the thalamus are considered, with a special emphasis on the effects of afferent interaction on the circadian timekeeping system. What is known of the endogenous clock mechanism is reviewed in comparison with known molecular circadian mechanisms in other species. Efferents of the SCN are also discussed with a view toward understanding how circadian information is transmitted to the rest of the central nervous system. Where possible, anatomical, electrophysiological, neuropharmacological, molecular, and behavioral data are integrated in an attempt to illuminate the mechanisms of circadian timekeeping.

Surgical neurology and clinical neurosciences in Edinburgh, Scotland

Surgical neurology in Edinburgh started > 70 years ago with Norman Dott, after his apprenticeship with Harvey Cushing. It continued under the chairmanship of John Gillingham, until 1980, and then Douglas Miller, who merged the Departments of Surgical Neurology and Medical Neurology to form the Department of Clinical Neurosciences in 1986. Particular strengths of the Edinburgh program have been the management of intracranial aneurysms, stereotactic and functional neurosurgery, the management of head and spinal injury and stroke, and neuro-oncology.

Inhibition of HIV-1 infectivity by low molecular weight heparin. Results of in vitro studies and a pilot clinical trial in patients with advanced AIDS

Several sulfated polysaccharides have been shown to have anti-HIV activity in vitro. However, many of these compounds are not suited for use in vivo because they present an increased risk of bleeding or cannot be administered chronically. We tested the anti-HIV effects of low molecular weight heparin (LMW-heparin) (Enoxaparin) in vitro using a model system of HIV infectivity because LMW-heparin can be given to patients on a long-term basis with little risk. In vitro, LMW-heparin was shown to inhibit HIV-1 production from a T cell lymphoma line (H9) and phytohemagglutinin-stimulated lymphoblasts. Inhibition of infectivity was dose dependent at concentrations achievable in vivo. We then performed a pilot clinical trial in 13 patients with advanced AIDS of 6 months of chronic, self-administered Enoxaparin given in standard prophylactic doses. CD4 counts appeared to stabilize or increase in most patients during the first 3 months of treatment, then remained stable or declined after 6 months. There was no appreciable change in serum p24 levels. There was no evidence of drug toxicity and no bleeding episodes. These findings demonstrate that a commercially available, relatively non-toxic form of LMW-heparin is a potent inhibitor of HIV-1 production in cultured cells and that it is feasible to treat patients with AIDS with LMW-heparin on a long-term basis. Definitive clinical trials of LMW-heparins and related compounds as experimental anti-viral agents in patients with HIV infection are indicated.

The influence of temperature, phylogeny, and lung structure on the lipid composition of reptilian pulmonary surfactant

The lungs of all air-breathing vertebrates contain a form of pulmonary surfactant that lines the alveolar air-water interface where it modifies the interfacial surface tension. These pulmonary surfactants all consist of varying amounts of phospholipids (saturated and unsaturated) and cholesterol. The extent of variation between vertebrate groups and between species within a vertebrate group has been attributed to differences in factors such as phylogeny, body temperature, habitat, and lung structure. The influence of these factors on amphibian surfactant composition and function has been studied, but the reptiles, which comprise a polyphyletic group of vertebrates, have never been critically examined. The surfactant lipid composition from species belonging to the three groups of reptiles, the Archosauria (crocodiles), Lepidosauria (snakes and lizards), and Anapsida (turtles), has been determined. New data is presented in conjunction with already published data to create an evolutionary framework that concentrates particularly on the influence of phylogeny, body temperature, and lung structure on the composition of the surfactant lipids. Large amounts of pulmonary surfactant were found in all species of reptiles. All species lavaged at 23 degrees C (except C. atrox) demonstrated DSP/PL ratios of 23-33%. Animals with multicameral lungs exhibited an elevated CHOL/DSP ratio compared with species with unicameral lungs. In all groups, phosphatidylcholine (PC) was the dominant (60-80%) phospholipid. Phosphatidylserine and phosphatidylinositol (PS/PI) and sphingomyelin (S) represented the other phospholipids, while phosphatidylglycerol (PG), lysophosphatidylcholine (LPC), and phosphatidylethanolamine (PE) were occasionally observed. In two species of lizards (C. nuchalis and P. vitticeps), the saturated fatty acid, palmitic acid (16:0), was the dominant tail group on the phospholipids. Oleic acid (18:1) was the dominant monounsaturated fatty acid, whereas polyunsaturates comprised about a fifth of the total fatty acid profile. Short-term (4 h) changes in temperature did not affect the relative proportions of the fatty acids in either species. Comparison of the current data with previously published literature suggests that phylogeny and habitat do not significantly influence surfactant lipid composition, but body temperature and to a lesser extent lung structure are important determinants of reptilian surfactant lipid composition.

Prostate-specific antigen expression is regulated by an upstream enhancer

Prostate cancer can be detected using assays for blood-borne prostate-specific antigen (PSA), which is the clinically most useful diagnostic marker of malignant disease. This paper characterizes the 5 -flanking prostate-specific enhancer which controls expression of the human PSA gene This enhancer, located between -5824 and -3738, is androgen-responsive and requires a promoter for activity. Inductions of 12-100-fold activity occur at 1 nM concentrations of the testosterone analog R1881. The enhancer demonstrated tissue specificity as judged by transfections of several human cell lines. Electrophoretic mobility shift assays comparing nuclear extracts from breast cancer cells MCF-7, and prostate cancer cells LNCaP, showed three regions of prostate-specific binding. These three regions are -4168 to -4797 (region I), -4710 to 4479 (region II), and -4168 to -3801 (region III). Region III contained a putative androgen response element at -4136 that markedly affected activity if mutated. These data suggest that prostate-specific gene expression may involve interaction of prostate-specific proteins or protein complexes with the enhancer in addition to binding of the androgen receptor to androgen response elements.

Ocular motor dysfunction in HIV-1-infected subjects: a quantitative oculographic analysis

We recorded eye and head movements in 13 human immunodeficiency virus type-1 (HIV-1)-infected patients with CD4 counts of less than or equal to 500 cells/mm3 using magnetic search coil oculography. Horizontal and vertical saccades, smooth pursuit, and vestibular smooth eye movements were recorded, as were horizontal antisaccades and vestibular memory-guided saccades. Rightward and leftward and upward and downward responses were analyzed separately. Compared to normal control subjects, HIV-1--infected patients performed the antisaccade test poorly, making the initial antisaccade in the correct direction (away from the target) in only 33% of trials. The mean final gaze position achieved during the vestibular memory-guided saccade task was less accurate for HIV-1-infected patients than for control subjects, and this correlated with inaccuracies on the antisaccade task. Horizontal saccades, horizontal and vertical smooth pursuit, and vestibular smooth eye movements were quantitatively normal. However, smooth pursuit showed directional asymmetries, vertically more than horizontally; horizontal and vertical unpredictable saccades were more inaccurate than predictable saccades; and vertical saccade latencies were prolonged. In patients with HIV-1 infection, abnormalities in vertical eye movements and relative asymmetries in smooth pursuit gains, both horizontally and vertically, are more sensitive and consistent indicators of CNS dysfunction than are horizontal eye movement abnormalities or measurements of absolute smooth pursuit gain and phase.

Disposition of 14C-derived residues in tissues of pigs fed radiolabelled fumonisin B1

The uptake and distribution of radioactive material-derived residues were determined in tissues of growing pigs consuming 14C-labelled fumonisin B1 (FB1) in the diet. Animals were fed 3.0 mg (3.0 microCi) 14C-FB1/kg feed from days 1-12, followed by 2.0 mg (2.0 microCi) 14C-FB1/kg feed during days 13-24, followed by a 9-day withdrawal period where pigs received clean feed only. Of the tissues analysed, residues were found to accumulate only in liver and kidney. Radioactivity was detected at the first sampling time (day 3), and continued to increase until the 14C-toxin was removed from the diet. Peak tissue levels (dpm/g tissue +/- SD, N = 2) in liver and kidney were 347 +/- 28 and 146 +/- 14, respectively, on day 24, which were equivalent to about 160 and 65 ng FB1 and/or metabolites per g tissue, respectively. Once pigs were placed on clean feed, tissue levels declined rapidly; down to approximately 35% of peak levels after 3 days, and only marginally above detection limits (approximately 25 dpm/g) after 9 days. Delayed recovery of the radioactive material consumed indicated a persistence within the body of FB1-derived residues, which could be eliminated only upon removal of the contaminated diet.

NMR structural studies of fumonisin B1 and related compounds from Fusarium moniliforme

Fumonisin B1 (FB1) is the primary mycotoxin produced by Fusarium moniliforme and appears to be responsible for the varied toxigenic effects associated with ingestion of this mold, particularly that of the inhibition of sphingolipid biosynthesis. Understanding the structure and biosynthesis of fumonisins is a key factor in determining structure/activity relationships. To this end, Nuclear Magnetic Resonance (NMR) methods have been used to identify various derivatives of FB1, both naturally occurring and synthetic. With accurate chemical shift assignments, NMR may be used to determine the level of impurities in toxicological grade FB1 preparations. Specifically enriched FB1 was prepared from F. moniliforme cultures using 13C-enriched acetate as well as several 13C-enriched amino acids. 13C NMR analysis indicates that the biosynthesis of fumonisins involves the addition of methionine-derived methyl functions, glutamate-derived tricarballylic ester functions and alanine to an 18 carbon hydrocarbon backbone that is likely polyketide in origin. With the goal of obtaining a crystalline compound for the determination of absolute configuration, several derivatives of FB1 have been prepared, and NMR analysis used to determine the relative and absolute configuration of the 10 stereocenters present in this molecule.

Biological fate of fumonisin B1 in food-producing animals

The presence of mycotoxins in grains and feedstuffs causes not only animal health problems, but also a valid concern about the transmission of potentially toxic residues into animal-derived products intended for human consumption. In a series of studies at Agriculture and Agri-Food Canada, we investigated the biological fate of fumonisin B1 (FB1) in several food-producing animals (grower pigs, laying hens, dairy cattle), as well as monitored various parameters for evidence of toxicity in these species. In several experiments involving either single-dose protocols (iv, po) or longer-term feeding trials, the pharmacokinetic profiles of FB1 (purity > 95%) in these species were determined, including tissue accumulation and transmission of residues. Toxicological (and economical) implications such as performance (feed consumption, growth), productivity, and carcass quality were also measured when appropriate.

Analysis of Fusarium causing dermal toxicosis in marram grass planters

In the European coastal dunes, marram grass (Ammophila arenaria) is planted in order to control sand erosion. In the years 1986 to 1991, workers on the Wadden islands in the Netherlands planting marram grass showed lesions of skin and mucous membranes, suggesting a toxic reaction. Fusarium culmorum dominated the mycoflora of those marram grass culms that were used for planting. This plant material had been cut and stored for more than one week in the open. The Fusarium toxin deoxynivalenol (DON) was detected in the suspect marram grass culms. Isolated F. culmorum strains were able to produce DON in vitro in liquid culture as well as in experimentally inoculated wheat heads. Pathogenicity tests, toxin test as well as RAPD analysis showed that the F. culmorum strains were not specialized for marram grass but may form part of the West-European F. culmorum population infecting cereals and grasses. Storage on old sand-dunes with plant debris may have led to the high occurrence of F. culmorum and contamination with DON. Marram grass culms should be obtained from young plantings on dunes on the seaward slopes and cut culms should not be stored.

Response of growing swine to dietary exposure to pure fumonisin B1 during an eight-week period: growth and clinical parameters

Consumption of corn or corn-based products contaminated with Fusarium moniliforme/fumonisins has been associated with a variety of animal and human diseases and is a major food/feed safety issue. This study focused on the clinical toxicity and performance parameters in growing swing exposed to low to moderate levels of pure fumonisin B1 (FB.) for 8 weeks. Male (castrated) and female pigs were fed diets containing 0,0.1,1.0, and 10 mg FB1/kg diet (ppm). Weight gains and feed consumption were measured weekly. Blood samples were collected throughout the study, and various clinical and hematological parameters were measured. Because fumonisins are potent inhibitors of sphingolipid biosynthesis, sphinganine and sphingosine concentrations were determined in the liver, lung, and kidney. Organ weights and carcass quality were measured at the end of the trial. In general, male pigs were more adversely affected by FB1 in the diet than females. The average daily gain for males decreased by 8% for pigs fed 1.0 ppm and by 11% at 10.0 ppm, when compared to the control (0 ppm). Males fed 0.1 ppm showed an erratic growth pattern during the first 5 weeks of the experiment. Feed consumption for the same animals was somewhat higher than that of the controls during each of the first 4 weeks but thereafter was 6-7% lower each week as compared to controls. Female pigs fed FB1-diets showed a general enhancement of feed consumption until week 4. Among clinical chemistry parameters, cholesterol increased in males for the 1.0 and 10.0 ppm diets as compared to controls after 2 weeks, while the levels in both sexes were elevated for the 1.0 ppm diet only by the end of the experiment. Serum liver enzyme concentrations were altered during week 2 only. Changes were observed in the weight of the pancreas and adrenals for male pigs fed FB1 diets as compared to controls. The free sphinganine to free sphingosine ratio (biomarker of exposure in FB1-consuming animals) increased in all three organs for the 10 ppm diet, regardless of sex. The study indicated that FB1 can cause different effects at each dose level, at concentrations as low as 0.1 ppm (showing erratic growth) followed by a reduced growth and biochemical abnormalities in blood (1.0 ppm) and sphingolipid alterations in tissues (10.0 ppm). Some of these effects occurred below the exposure level that caused alteration in sphingolipid metabolism.

Fumonisin B1 toxicity in male Sprague-Dawley rats

Male rats were gavaged with fumonisin B1 (FB1) once daily for 11 consecutive days at doses of 0, 1, 5, 15, 35, and 75 mg FB1/kg body weight. Urine osmolality (at 5-75 mg FB1/kg) and organic ion transport in kidney slices (at 5-75 mg FB1/kg) were reduced. Urinary excretion of protein (at 15-75 mg FB1/kg) and of the enzymes LDH (at 5-75 mg FB1/kg), NAG (at 5-75 mg FB1/kg) and GGT (at 15-75 mg FB1/kg) were increased. These findings were indicative of glomerular and tubular toxicity. Histopathologic changes in the kidney consisted of necrosis of tubular epithelia of variable extent accentuated in the inner cortex. These changes were present at 1 and 5 mg FB1/kg and were more pronounced at 15-75 mg FB1/kg. Serum enzymes indicative of hepatotoxicity (ALT, GGT) were elevated compared to controls at 75 mg FB1/kg only. There were noticeable increases in mitotic figures in hepatocytes at 35-75 mg FB1/kg, while single cell necroses were increasingly numerous from 15-75 mg FB1/kg. The kidneys were considered to be the primary target organs in this study.

Middle cerebral artery blood flow velocity in patients with cirrhosis

BACKGROUND

Brain dysfunction is common in patients with advanced liver disease; it is often manifested as hepatic encephalopathy, but its cause is not clearly understood.

METHODOLOGY

Intracranial blood flow velocity parameters, including peak systolic velocity, end diastolic velocity and mean velocity of both middle cerebral arteries were measured by transcranial Doppler ultrasonography in 37 patients with cirrhosis without encephalopathy (16 Child's A, 10 Child's B and 11 Child's C) and 12 normal controls. The cause was alcohol-related in 24 and non-alcohol-related in 13.

RESULTS

No significant differences in any of the Doppler parameters were detected in Child's group A when compared with controls. However, a statistically significant decrease in middle cerebral artery blood flow velocity was evident when Child's B and C patients without clinically apparent encephalopathy were compared with controls irrespective of the cause. Our results demonstrate that intracranial blood flow is abnormal in patients with advanced liver disease without clinically apparent encephalopathy.

Bioactive isocoumarins and related metabolites from conifer endophytes

Six new [1-4, 7, 9] and two known [6 and 8] metabolites have been isolated from culture filtrates of conifer endophyte strains of Canoplea elegantula. Their structures have been determined by spectroscopic means. Compound 1 was toxic to spruce budworm cells, and both 1 and 3 were toxic to spruce budworm larvae.

The regulation of acetylated microtubules during outgrowth from cultured neurons of the snail, Helisoma

Axonal stumps of cultured Helisoma trivolvis neurons express abundant acetylated microtubules, as a subset of total microtubules. Label completely disappears from the axonal remnants within approximately 1 day, and reappears in newly extended neurites over the course of the next 3-4 days, first in the proximal neurite as short, isolated segments. Acetylated microtubules occur in the neuritic shaft, but never in growth cones or membranous veils. Thus, acetylated microtubules are very labile to the signals generated by axotomy, and their proximodistal re-expression occurs at well separated sites within the neurite as it matures.

The adverse drug reaction: a clinical opportunity for pharmacists

A program is presented that gives the pharmacist the clinical opportunity to assess and evaluate adverse drug reactions in the hospital setting. An adverse drug reaction protocol is discussed that addresses reporting and patient care issues. The pharmacist performs adverse drug reaction assessment at the patient bedside as part of a multidisciplinary team consisting of the pharmacist, nurse, and physician. The protocol provides a method of concurrent adverse drug reaction monitoring and involves the patient in the reporting process.

An amino-terminal domain containing hydrophobic and hydrophilic sequences binds the signal recognition particle receptor alpha subunit to the beta subunit on the endoplasmic reticulum membrane

The signal recognition particle receptor consists of two subunits of 72 kDa (SR alpha) and 30 kDa (SR beta). Assembly of SR alpha on the endoplasmic reticulum membrane can occur independent of the signal recognition particle-mediated translocation pathway. To identify the sequences within SR alpha necessary for membrane binding, a series of amino-terminal and internal deletion mutants was constructed and translated in a cell-free system. In addition, nascent SR alpha polypeptides of varying lengths were generated by cycloheximide treatment of translation reactions. Microsome binding assays performed on these polypeptides revealed a membrane binding domain consisting of the amino-terminal 140 residues of SR alpha. This domain includes the two hydrophobic sequences originally proposed to bind to membranes and a highly charged region not previously implicated in membrane assembly. Furthermore, the domain forms a protease-resistant folding unit that after proteolysis can target and anchor onto microsomes. Extraction of microsomal SR alpha at high pH supplemented with 1 M NaSCN suggests that SR alpha and the membrane binding domain are not integrated in the endoplasmic reticulum membrane. The membrane binding domain is also the major site of tight binding with SR beta, suggesting that SR beta plays a role in the membrane assembly of SR alpha.

Differential binding of vascular cell-derived proteoglycans (perlecan, biglycan, decorin, and versican) to the beta-amyloid protein of Alzheimer's disease

Previous studies have demonstrated the immunolocalization of perlecan, a specific heparan sulfate proteoglycan, to the beta-amyloid protein (A beta)-containing amyloid deposits within the walls of blood vessels (i.e., congophilic angiopathy) in Alzheimer's disease (AD) brain. In the present investigation, the differential binding of previously characterized endothelial cell (EC)- and smooth muscle cell (SMC)-derived PGs to A beta was examined to determine whether the accumulation of A beta in cerebrovascular amyloid deposits may be due to its interactions with perlecan. Pretreatment of AA amyloidotic splenic and liver tissue sections with synthetic A beta (1-28) produced strong immunoreactivity with A beta antibodies at tissue sites enriched in perlecan which was partially removed by pretreatment with heparitinase, but not by chondroitin ABC lyase. [35S]-Sulfate labeled proteoglycans (PGs) derived from cultured ECs and SMCs bound to affinity columns containing A beta (1-28) or (1-40), with virtually no binding to A beta (40-1) (reverse peptide), beta-amyloid precursor protein (410-429), or bovine serum albumin. Characterization of EC and SMC PGs bound to A beta (1-28) revealed strong binding by perlecan, weak binding by decorin and biglycan, two dermatan sulfate proteoglycans, and lack of binding by versican/PG-M, a large chondroitin sulfate proteoglycan. Binding of 125I-labeled perlecan to A beta (1-28) was strongly inhibited by isolated perlecan and to a lesser extent by heparin, but not by chondroitin-6-sulfate or unsulfated dextran sulfate. Heparitinase treatment decreased, but did not eliminate the binding of 125I-labeled perlecan to A beta (1-28). Scatchard analysis of the interaction of A beta (1-28)- and EC-derived perlecan in solid-phase assays indicated high-affinity (Kd = 8.3 x 10(-11) M) and lower-affinity (Kd = 4.2 x 10(-8) M) binding sites, with approximately 1 mol of perlecan binding 1.8 mol of A beta. A significant decrease in binding of EC-derived perlecan to A beta (1-28) was observed when a sequence within the putative heparin-binding motif of A beta (His13His14Gln15Lys16) was replaced by the uncharged peptide sequence, Gly13Gly14Gln15Gly16, indicating a perlecan binding site on A beta near the postulated alpha-secretase site (at Lys-16). Overall, the results indicate that specific vascular cell-derived PGs differentially interact with A beta, and that the interactions of highest affinity occur between A beta and binding sites on both the core protein and glycosaminoglycan chains of perlecan.(ABSTRACT TRUNCATED AT 400 WORDS)

The evaluation of the wave-form analysis capability of a new strain-gauge intracranial pressure MicroSensor

Both laboratory and clinical trials have indicated the reliability of a new catheter-tip, strain-gauge intracranial pressure transducer. We report on the results of bench tests comparing the wave-form analysis capabilities of the new Codman intracranial pressure MicroSensor and a similar strain-gauge transducer. Good agreement was found between the two sensors with no significant nonlinearity or hysteresis over a measured pressure range from 0 to 100 mg Hg. Under "fluid-filled" conditions, the MicroSensor showed good reproduction of an arterial pressure wave form; when spectral analysis was used to analyze the two sensor types and break them down into harmonic components, no significant differences could be found for any of the first 10 amplitude and phase harmonics. If proven to stay robust after long-term clinical use, this sensor may be a useful alternative to the existing transducer systems for routinely monitoring the intracranial pressure and its wave form.

Chromosomal location of genes for stem rust resistance derived from 'Waldron' wheat

The chromosomal locations of genes for resistance to stem rust (Puccinia graminis Pers.: Pers. f. sp. tritici Eriks. & E. Henn.) in the wheat (Triticum aestivum L.) cultivar 'Waldron' (WDR) were determined by monosomic analyses. Wheat lines WDR-B1, -C2, -E4, and -F1,which have single genes for resistance to stem rust derived previously from WDR sel. 'Little Club', were crossed onto a complete set of 21 'Chinese Spring' monosomics. The F2 and backcross-F1 (BC1F1) seedlings from each of the 84 crosses were tested for reaction to culture 111-SS2 (CRL-LCBB) of stem rust, and a few selected segregants were analyzed cytologically for chromosome number. The F2 from 2 crosses of WDR-C2, -E4 and -F1 and the BC1F1 from 2 crosses of WDR-F1 were tested also with culture Or11c (CRL-QBCN). Significant deviations from disomic ratios towards monosomic ratios in the F2 and BC1F1 were used to determine which chromosomes carried the genes for resistance. Cytological analyses of certain BC1F1 and susceptible F2 plants were used to help identify the location of the genes for rust resistance. WDR-B1 has a gene, herein designated Sr41, for resistance on chromosome 4D. WDR-C2 has a gene on chromosome 7 A that may be the same as one previously designated SrWld2. WDR-E4 has a gene on chromosome 2A, possibly SrWld1, which is effective against most or all North American stem rust cultures. WDR-F1 has a gene on chromosome 6B that is the same as or similar to Sr11.

Wheat lines monogenic for resistance to stem rust from the wheat cultivar 'Waldron'

The Triticum aestivum L. cultivar 'Waldron' has long lasting resistance to most North American stem rust (Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. and E. Henn.) isolates. The objective of this research was to develop wheat lines monogenic for resistance to stem rust from 'Waldron' using allelism tests and tests for reaction to a series of ten stem rust cultures having a range of virulences. Twelve lines homozygous for single resistance genes were selected as parents of a diallel cross to test for allelism among genes for resistance. We identified 6 lines or groups of lines (WDR-A1, the WDR-B1 and WDR-B2 group, the WDR-C1 and WDR-C2 group, WDR-D1, the WDR-E1, WDR-E2, WDR-E3, and WDR-E4 group, and WDR-F1) that carried different single genes for resistance from 'Waldron'. A seventh line (WDR-G1) probably has two genes for resistance, one in common with WDR-C1 and WDR-C2. The gene in the WDR-E group is probably the same as SrWld1, and the one in WDR-F1 the same as Sri11. 'Waldron' probably has two or more genes for resistance to stem rust that previous genetic studies did not detect.

Nicotine phase-advances the circadian neuronal activity rhythm in rat suprachiasmatic nuclei explants

In vivo studies reported that cholinergic agents affect mammalian circadian rhythmicity. To study phase resetting properties of cholinergic compounds more directly, we carried out experiments in rat suprachiasmatic nuclei slices. Compounds were added to the perfusate for 1 h at specific phases of the circadian cycle. On the following day, the time of peak neuronal activity, a measure of the phase of the endogenous circadian pacemaker, was assessed by means of extracellular recording in the suprachiasmatic nuclei. The peak of neuronal activity occurred at circadian time 5.8 +/- 0.7 (mean +/- 95% confidence limits) in the control slice (circadian time 0: lights-on). Ten-micromolar carbachol had no effect on the phase of the circadian rhythm when given at circadian times 6 and 15, while at circadian time 21 a phase advance of one hour was observed. By contrast, 10 microM nicotine significantly phase advanced (> 1 h) the neuronal circadian rhythm at all but one experimental circadian phase. The circadian times of maximal nicotinic phase advances were 15 (+2.6 h) and 21 (+2.8 h). A concentration response curve for nicotine was generated and pharmacological blocking experiments were performed at circadian time 15. The estimated maximum response of nicotine was 3.4 h, and the estimated concentration for half maximal response was 5 microM. The Hill coefficient (= 1.08) indicated that the effects of nicotine may be explained by a single receptor occupancy model. Mecamylamine (20 microM) almost completely antagonized the nicotinic phase-advances, whereas tetrodotoxin (1 microM) or high Mg2+ (10 mM) did not significantly attenuate the nicotinic phase-advances.(ABSTRACT TRUNCATED AT 250 WORDS)

A formant bandwidth estimation procedure for vowel synthesis [43.72.Ja]

The specification of vowel formant bandwidths for speech synthesis has been inconsistent in the past, perhaps due to the difficulty of measuring formant bandwidths in natural speech and the possible perceptual insignificance of formant bandwidths on the intelligibility of synthetic speech. Here, regression equations are presented for the estimation of formant bandwidths based on measurements from natural speech which is based only on formant center frequency and independent of other formant values. Current usage, as well as comparison with another well-known estimation algorithm suggests that the new procedure should be quite acceptable for some types of speech synthesis.

The beta subunit of the signal recognition particle receptor is a transmembrane GTPase that anchors the alpha subunit, a peripheral membrane GTPase, to the endoplasmic reticulum membrane

The signal recognition particle receptor (SR) is required for the cotranslational targeting of both secretory and membrane proteins to the endoplasmic reticulum (ER) membrane. During targeting, the SR interacts with the signal recognition particle (SRP) which is bound to the signal sequence of the nascent protein chain. This interaction catalyzes the GTP-dependent transfer of the nascent chain from SRP to the protein translocation apparatus in the ER membrane. The SR is a heterodimeric protein comprised of a 69-kD subunit (SR alpha) and a 30-kD subunit (SR beta) which are associated with the ER membrane in an unknown manner. SR alpha and the 54-kD subunits of SRP (SRP54) each contain related GTPase domains which are required for SR and SRP function. Molecular cloning and sequencing of a cDNA encoding SR beta revealed that SR beta is a transmembrane protein and, like SR alpha and SRP54, is a member of the GTPase superfamily. Although SR beta defines its own GTPase subfamily, it is distantly related to ARF and Sar1. Using UV cross-linking, we confirm that SR beta binds GTP specifically. Proteolytic digestion experiments show that SR alpha is required for the interaction of SRP with SR. SR alpha appears to be peripherally associated with the ER membrane, and we suggest that SR beta, as an integral membrane protein, mediates the membrane association of SR alpha. The discovery of its guanine nucleotide-binding domain, however, makes it likely that its role is more complex than that of a passive anchor for SR alpha. These findings suggest that a cascade of three directly interacting GTPases functions during protein targeting to the ER membrane.

NEsting by the hawsbill turtle (Eretmochelys imbricata) on Milman Island, Great Barrier Reef, Australia

Nesting biology of hawksbill sea turtles (Eretmochelys imbricata) is described with morphometric and meristic measurements collected from 365 turtles over 76 nights of beach patrols on Milman I. The nesting season was already in progress when the study began in January and continued after the research team left in March 1991. Average renesting interval was 14.2 days, and the hawksbill turtles laid an average of 2.6 clutches during the study period. Nest sites were located most commonly under trees (67.2%). Average curved carapace length was 81.7 cm, width was 70.6 cm, and weight after laying was 50.3 kg. Mean clutch size was 124 eggs. Eggs had an average diameter of 3.48 cm and an average weight of 25.7 g. Emergence success rate was 79.9% for hawksbill hatchlings, which had an average straight carapace length of 3.96 cm and weight of 13.3 g. Incubation temperatures were monitored and sex ratios determined in four clutches, two in shaded and two in unshaded sand. The sexes of 25 hatchlings from each clutch were identified. Two unshaded clutches produced 92% and 100% female hatchlings while two shaded clutches produced 64% and 44% female hatchlings. Statistical differences were not found between the presented hawksbill turtle curved carapace length, weight after laying and clutch size and those collected elsewhere in Queensland by earlier studies.

Phytotoxic effect of deoxynivalenol and gibberella ear rot resistance of corn

The Fusarium graminearum mycotoxin deoxynivalenol was shown to be more phytotoxic to corn genotypes susceptible to gibberella ear rot than resistant genotypes. The toxin caused greater damage to the membranes of the susceptible genotypes, as evidenced by the release of Na and K ions into solution. Isolated protoplasts of ear rot-resistant genotypes were able to bind more radiolabelled deoxynivalenol than those of susceptible genotypes, providing a partial explanation for the membrane tolerance to the toxin. The results are discussed in relation to the role of resistance to this phytotoxin and tolerance to gibberella ear rot.

Integrated multimodality monitoring in the neurosurgical intensive care unit

The selection of variables for continuous monitoring in the neurosurgical intensive care unit is based upon the requirement for constant perfusion and oxygenation of the brain and knowledge of the frequency and prognostic significance of abnormal values. Both arterial and intracranial pressure must be considered in the form of cerebral perfusion pressure. Body temperature and arterial oxygen saturation are essential to monitoring. Measurement of jugular venous oxygen saturation and cerebral blood flow velocity provide information of value in determining the source of raised intracranial pressure, the most appropriate means of treating it, and the safety of therapy.

Determination of fumonisins in milk

Fumonisin B1 (FB1) and fumonisin B2 (FB2) were determined in milk by liquid chromatography (LC) following immunoaffinity column cleanup. Recoveries from milk spiked with 5-50 ng each fumonisin/ml averaged 79-109%. The aminopentol hydrolysis product of FB1 (AP1) was determined by LC after cleanup on a C18 solid phase phase extraction column; mean recoveries were 69-83% at spiking levels of 50-100 ng AP1/ml milk. Detection limits were of the order 3-7 ng/ml for FB1 and FB2, and 20-25 ng/ml for AP1. A stability study showed no losses of FB1 and FB2 in milk under conditions of freezing, refrigeration and boiling. A transmission study using four cows dosed with pure FB1 either orally (1.0 and 5.0 mg FB1/kg b.w.) or by i.v. injection (0.05 and 0.20 mg FB1/kg b.w.) showed no detectable residues of FB1 or AP1 in the milk, with or without hydrolytic treatment with beta-glucuronidase/sulfatase to liberate any conjugates.