Automatic classification of DMSA scans using an artificial neural network.

DMSA imaging is carried out in nuclear medicine to assess the level of functional renal tissue in patients. This study investigated the use of an artificial neural network to perform diagnostic classification of these scans. Using the radiological report as the gold standard, the network was trained to classify DMSA scans as positive or negative for defects using a representative sample of 257 previously reported images. The trained network was then independently tested using a further 193 scans and achieved a binary classification accuracy of 95.9%. The performance of the network was compared with three qualified expert observers who were asked to grade each scan in the 193 image testing set on a six point defect scale, from 'definitely normal' to 'definitely abnormal'. A receiver operating characteristic analysis comparison between a consensus operator, generated from the scores of the three expert observers, and the network revealed a statistically significant increase (α < 0.05) in performance between the network and operators. A further result from this work was that when suitably optimized, a negative predictive value of 100% for renal defects was achieved by the network, while still managing to identify 93% of the negative cases in the dataset. These results are encouraging for application of such a network as a screening tool or quality assurance assistant in clinical practice.

The angiotensin IV analog Nle-Tyr-Leu-psi-(CH2-NH2)3-4-His-Pro-Phe (norleual) can act as a hepatocyte growth factor/c-Met inhibitor.

The angiotensin (Ang) IV analog norleual [Nle-Tyr-Leu-psi-(CH2-NH2)(3-4)-His-Pro-Phe] exhibits structural homology with the hinge (linker) region of hepatocyte growth factor (HGF) and is hypothesized to act as a hinge region mimic. Norleual competitively inhibited the binding of HGF to its receptor c-Met in mouse liver membranes, with an IC(50) value of 3 pM. Predictably, norleual was able to inhibit HGF-dependent signaling, proliferation, migration, and invasion in multiple cell types at concentrations in the picomolar range. Ex vivo studies demonstrated that norleual exhibited potent antiangiogenic activity, an attribute that would be predicted for a HGF/c-Met antagonist. Furthermore, norleual suppressed pulmonary colonization by B16-F10 murine melanoma cells, which are characterized by an overactive HGF/c-Met system. Together, these data suggest that AngIV analogs exert at least some of their biological activity through interference with the HGF/c-Met system and may have utility as therapeutic agents in disorders that are dependent on an intact HGF/c-Met system. Finally, the ability of norleual to induce marked biological responses in human embryonic kidney cells, which do not express insulin-responsive aminopeptidase (IRAP), coupled with the observed effects of norleual on the HGF/c-Met system, casts doubt on the physiological significance of AngIV-dependent inhibition of IRAP. [Corrected]

The effect of recombinant aminopeptidase A on hypertension in spontaneously hypertensive rats: its effect in comparison with candesartan.

An understanding of aminopeptidase A in hypertension is important, given its ability to cleave the N-terminal aspartic acid of potent vasoconstrictor angiotensin II. However, the role of aminopeptidase A in hypertension has received limited attention. Because we have succeeded in producing recombinant human aminopeptidase A, the effect of aminopeptidase A on systolic blood pressure in the spontaneously hypertensive rat was examined. Aminopeptidase A of 0.016 mg/kg was administrated intravenously to spontaneously hypertensive rats and blood pressure was monitored for 72 h. For repeated administration, aminopeptidase A doses of 0.016 mg/kg and 0.1-mg/kg doses of candesartan (an angiotensin II receptor 1 subtype blocker) were administrated daily in spontaneously hypertensive rats and blood pressure was monitored for 5 d. Bolus intravenous injection of aminopeptidase A at a dose of 0.016 mg/kg significantly decreased systolic blood pressure for 36 h in spontaneously hypertensive rats. A comparison of the antihypertensive effects of aminopeptidase A versus candesartan in spontaneously hypertensive rats showed that the effective dose of aminopeptidase A was about one-tenth that of candesartan. These results suggest the novel approach of utilizing aminopeptidase A to treat hypertension by degrading circulating angiotensin II before it binds to the receptor 1 subtype.

AT4 receptor activation increases intracellular calcium influx and induces a non-N-methyl-D-aspartate dependent form of long-term potentiation.

The angiotensin 4 receptor (AT4) subtype is heavily distributed in the dentate gyrus and CA1-CA3 subfields of the hippocampus. Neuronal pathways connecting these subfields are believed to be activated during learning and memory processing. ur laboratory previously demonstrated that application of the AT4 agonist, Norleucine1-angiotensin IV, enhanced baseline synaptic transmission and long-term potentiation, whereas perfusion with the AT4 antagonist, Norleucine1-Leu3-psi(CH2-NH2)3-4-angiotensin IV disrupted long-term potentiation stabilization in area CA1. The objective of the present study was to identify the mechanism(s) responsible for Norleucine1-angiotensin IV-induced increase in hippocampal long-term potentiation. Hippocampal slices perfused with Norleucine1-angiotensin IV for 20 min revealed a notable increase in baseline responses in a non-reversible manner and were blocked by the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione disodium salt. Infusions of Norleucine1-angiotensin IV prior to, but not after theta burst stimulation, significantly enhanced long-term potentiation compared with control slices. Further, N-methyl-D-aspartate receptor-independent long-term potentiation could be induced by tetanization during the perfusion of Norleucine1-angiotensin IV in the presence of the N-methyl-D-aspartate antagonist, D,L-2-amino-5-phosphonovaleric acid. Blockade of select voltage dependent calcium channels significantly reduced Norleucine1-angiotensin IV-induced increase in baseline responses and subsequent long-term potentiation suggesting that AT4 receptor activation increases intracellular calcium levels via altering voltage dependent calcium channels and triggers an N-methyl-D-aspartate-independent form of long-term potentiation. In support of this notion the application of Nle1-angiotensin IV to cultured rat hippocampal neurons resulted in increased intracellular calcium derived exclusively from extracellular sources. Consistent with these observations Nle1-angiotensin IV was capable of augmenting the uptake of 45Ca2+ into rat hippocampal slices. Taken together, these data indicate that increased calcium influx through postsynaptic calcium channels contribute to Norleucine1-angiotensin IV-induced enhancement of long-term potentiation.

Selection on floral characters in natural Spanish populations of Silene latifolia.

In insect-pollinated plants, floral characters are expected to play an important role in paternal and maternal reproductive success. Bateman's principle states that male reproductive success increases with more mating opportunities, while female reproductive success is limited by the amount of resources available to produce progeny, thus there should be greater selection on male floral characters than on female. In the case of the dioecious plant Silene latifolia, floral characters are likely to be influenced by its association within its native European range with moths of the genus Hadena, which serve as both pollinators and seed predators. The present study addresses relationships between male and female reproductive success, spatial location and floral characters (corolla, calyx and claw) over a 2-year period in two Spanish populations of S. latifolia in the presence of Hadena moths. A maximum likelihood paternity analysis using genetic variation at six allozyme markers showed heterogeneity in male reproductive success. There was much less variation in female reproductive success. When this analysis was extended to include interplant distance as a causal factor underlying variation in male success, we found that successful pollination tended to be limited to nearby females, in accordance with exponential decay of pollen dispersal with increasing distance. When the paternity analysis included floral characters as a causal factor underlying variation in male success, our data showed little evidence for directional selection, but there was stabilizing selection in one of the two years for calyx diameter. Selection on female characters varied widely between sites and years, in most of the site/year combinations there was little selection on female floral characters; however, in one site/year there was evidence for selection on all three floral characters. We conclude that pollinators visit flowers that are close together, and that while floral characters are important for the attraction of pollinators, larger flowers do not necessarily attract more pollinators at all sites and that variation among sites and years makes difficult any conclusions about the long-term importance of the predictions suggested by Bateman's principle.

Adiposity, insulin and lipid metabolism in post-menopausal women.

OBJECTIVE: To investigate relationships between body fat and its distribution and carbohydrate and lipid tolerance using statistical comparisons in post-menopausal women. DESIGN: Sequential meal, postprandial study (600 min) which included a mixed standard breakfast (30 g fat) and lunch (44 g fat) given at 0 and 270 min, respectively, after an overnight fast. SUBJECTS: Twenty-eight post-menopausal women with a diverse range of body weight (body mass index (BMI), mean 27.2, range 20.5-38.8 kg/m2) and abdominal fat deposition (waist, mean 86.4, range 63.5-124.0 cm). Women with BMI < 18 or > 37 kg/m2, age > 80 y and taking hormone replacement therapy (HRT) were excluded. MEASUREMENTS: Anthropometric measurements were performed to assess total and regional fat deposits. The concentrations of plasma total cholesterol, high density lipoprotein (HDL) cholesterol, triacylglycerol (TAG), glucose, insulin (ins), non-esterified fatty acids (NEFA) and apolipoprotein (apo) B-48 were analysed in plasma collected at baseline (fasted state) and at 13 postprandial time points for a 600 min period. RESULTS: Insulin concentrations in the fasted and fed state were significantly correlated with all measures of adiposity (BMI, waist, waist-hip ratio (W/H), waist-height ratio (W/Ht) and sum of skinfold thickness (SSk)). After controlling for BMI, waist remained significantly and positively associated with fasted insulin (r=0.559) with waist contributing 53% to the variability after multiple regression analysis. After controlling for waist, BMI remained significantly correlated with postprandial (IAUC) insulin (r=0.535) contributing 66% of the variability of this measurement. No association was found between any measures of adiposity and glucose concentrations, although insulin concentration in relation to glucose concentration (glucose-insulin ratio) was significantly negatively correlated with all measures of adiposity. A significant positive correlation was found between fasted TAG and BMI (r=0.416), waist (r=0.393) and Ssk (r=0.457) and postprandial (AUC) TAG with BMI (r=0.385) and Ssk (r=0.406). A significantly higher postprandial apolipoprotein (apo) B-48 response was observed in those women with high BMI (> 27 kg/m2). Fasting levels of NEFA were significantly and positively correlated with all measures of adiposity (except W/H). No association was found between cholesterol containing particles and any measure of adiposity. CONCLUSION: Hyperinsulinaemia associated with increasing body fat and central fat distribution is associated with normal glucose but not TAG or NEFA concentrations in postmenopausal women.

A role for the angiotensin AT4 receptor subtype in overcoming scopolamine-induced spatial memory deficits.

There is increasing interest in the role of the brain angiotensin AT4 receptor subtype in cognitive processing. This receptor subtype is activated by angiotensin IV (AngIV), is heavily distributed in the mammalian hippocampus, neocortex, and cerebellum, and has been linked with a learning and memory function. The present investigation utilized intracerebroventricular (i.c.v.)-infused scopolamine hydrobromide (scop), a muscarinic receptor antagonist, to disrupt acquisition of the circular water maze task of spatial memory. All animals received 2 days of training trials (five trials/day) using a visible platform in an effort to preclude subsequent confounding by scopolamine-induced sensory and/or motor impairments. In the first experiment, i.c.v.-infused scopolamine (70 nmol) was followed by 0, 10, 100, or 1000 pmol i.c.v. doses of Nle(1)-AngIV in separate groups of rats. Results indicated that each dose of Nle(1)-AngIV improved the poor acquisition of this task induced by scopolamine treatment. However, the 100- and 1000-pmol doses were most effective with respect to latency and distance to find the submerged pedestal. A second experiment demonstrated that treatment with a specific AT4 receptor antagonist, Nle(1), Leual(3)-AngIV (1000 pmol), blocked the ability of Nle(1)-AngIV (100 pmol) to improve the performance of scopolamine-compromised rats. These results support the notion that hippocampal AT4 receptors are involved in spatial memory processing, and that activation of these binding sites can overcome the disruption of spatial memory accompanying treatment with a muscarinic receptor antagonist.

Topical 0.2 percent glyceryl trinitrate ointment has a short-lived effect on resting anal pressure.

PURPOSE: Glyceryl trinitrate ointment applied to the anal verge lowers anal resting pressure, but its duration of action is uncertain. This study investigated the effect and duration of action of 0.2 percent glyceryl trinitrate on anal resting pressure and hemodynamic parameters. METHODS: A total of 15 volunteers, 9 male, with a median age of 30 (range, 20-71) years, underwent continuous static anal manometry using a solid state catheter for ten minutes before and two hours after applying 0.2 percent glyceryl trinitrate ointment to the anoderm with a gloved finger. Pulse and blood pressure were recorded every 15 minutes. RESULTS: A significant reduction in maximal anal resting pressure compared with preglyceryl trinitrate values was observed at 15, 30, 45, 60, and 90 minutes after application, but no significant difference thereafter. There was no significant change in pulse during the study. Systolic and diastolic blood pressures dropped significantly after application of glyceryl trinitrate, but had recovered and were not significantly different from original values after 90 minutes. A significant fall in blood pressure did not correlate with the onset or duration of side effects. CONCLUSIONS: Continuous static manometry (as opposed to interval measurements reported in previous studies) demonstrates that 0.2 percent glyceryl trinitrate ointment significantly lowers anal resting pressure, but only for 90 minutes. Twice daily application of topical 0.2 percent glyceryl trinitrate heals two-thirds of fissures after eight weeks, but its apparently short duration of action may indicate that more frequent application might heal more fissures, more rapidly.

Angiotensin IV enhances LTP in rat dentate gyrus in vivo.

Angiotensins have been shown to play a significant role in a variety of physiological functions including learning and memory processes. Relatively recent evidence supports the increasing importance of angiotensin IV (Ang IV), in many of these functions previously associated only with Ang II, including learning and memory. An interesting hypothesis generated by these results has been that Ang II is a precursor for the production of a more active peptide fragment, Ang IV. Since Ang II impairs learning and memory, when administered directly or released into the hippocampal dentate gyrus, and inhibits long term potentiation (LTP) in medial perforant path-dentate granule cell synapses, as well; it remained to be seen what effects Ang IV had on LTP in these same synapses. Results of this study show clearly that Ang IV significantly enhances LTP, and the enhancement is both dose and time dependent. The following solutions of Ang IV were administered over a five min period, at the end of baseline and before the first tetanus was applied: 2.39, 4.78, and 9.56 nM. An inverted U-type dose related effect was observed. A complex time related effect was observed with a maximum at 5 min, a return to normal LTP at 30 min and a minimum below normal at 90 min, and a return to normal LTP at 120 min. The effects of the 4.78 nM solution were determined at the following intervals between administration and the first tetanus: 5, 15, 30, 60, 90, and 120 min. The enhancement of LTP can be prevented by pretreatment with Divalinal, an Ang IV antagonist, without any effect on normal LTP. Two solutions of Divalinal were used; 5 nM and 5 microM, and the 5 microM was more effective and completely blocked the enhancement of normal LTP. Results were also obtained with 4.78 nM Nle1-Ang IV (Norleucine), an Ang IV agonist. Norleucine was less effective than Ang IV in the enhancement of normal LTP and displayed a similar time course of activity. Both Ang IV and Norleucine produced a significant suppression of normal LTP at 90 min; that remains to be explained. However, the inhibition by Ang IV was dose dependent and was blocked by Divalinal. The fact that the Ang IV enhancement of normal LTP was blocked by losartan, an Ang II AT1 receptor antagonist, is puzzling since Divalinal had no effect on the inhibition of LTP by Ang II.

A role for the angiotensin IV/AT4 system in mediating natriuresis in the rat.

Angiotensin II (AngII) or Angiotensin IV (AngIV) was infused into the renal artery of anesthetized rats while renal cortical blood flow was measured via laser Doppler flowmetry. The infusion of AngII produced a significant elevation in mean arterial pressure (MAP) with an accompanying decrease in cortical blood flow, glomerular filtration rate (GFR), urine volume, and urine sodium excretion. The infusion of AngIV induced significant increases in renal cortical blood flow and urine sodium excretion, without altering MAP, GFR, and urine volume. Pretreatment infusion with a specific AT1 receptor antagonist, DuP 753, blocked or attenuated the subsequent AngII effects, while pretreatment infusion with the specific AT4 receptor antagonist, Divalinal-AngIV, blocked the AngIV effects. These results support distinct and opposite roles for AngII and AngIV, i.e. AngII acts as an anti-natriuretic agent, while AngIV acts as a natriuretic agent.

Cell type-specific expression of fasciclin II isoforms reveals neuronal-glial interactions during peripheral nerve growth.

During the formation of the insect peripheral nervous system (PNS), the cell adhesion receptor fasciclin II has been shown to play a prominent role in axonal fasciculation and synapse formation during motor neuron outgrowth. In the moth Manduca, fasciclin II (MFas II) is expressed both as a transmembrane isoform (TM-MFas II) and a glycosyl phosphatidylinositol-linked isoform (GPI-MFas II). By using RNA and antibody probes, we have shown that these two isoforms are expressed in nonoverlapping patterns: TM-MFas II is expressed exclusively by neurons and becomes localized to their most motile regions, while GPI-MFas II is expressed primarily by the glial cells that ensheath the peripheral nerves. This cell-type specificity of expression allowed us to monitor the nature of neuronal-glial interactions during PNS development. The outgrowth of TM-MFas II-positive axons in many regions preceded the arrival of GPI-MFas II-expressing glial processes that enwrapped them. In a few key locations, however, GPI-MFas II-positive glial cells differentiated before the arrival of the first axons and prefigured their subsequent trajectories. Prior inhibition of GPI-MFas II expression disrupted the subsequent outgrowth of axons at these locations but not elsewhere in the PNS. Our results suggest that the two isoforms of MFas II play distinct roles with respect to cellular motility and nerve formation.

The effects of angiotensin IV analogs on long-term potentiation within the CA1 region of the hippocampus in vitro.

Within the brain-renin angiotensin system, it is generally assumed that angiotensin peptide fragments shorter than angiotensins II and III, including angiotensin IV (AngIV), are inactive. This belief has been challenged by the recent discovery that AngIV, and AngIV-like analogs, bind with high affinity and specificity to a putative angiotensin binding site termed AT4. In the brain these sites include the hippocampus, cerebellum, and cerebral cortex, and influence associative and spatial learning tasks. The present study investigated the effects of two AngIV analogs, Nle1-AngIV (an AT4 receptor agonist) and Nle1-Leual3-AngIV (an AT4 receptor antagonist), on long-term potentiation (LTP). Field excitatory postsynaptic potentials (fEPSPs) were recorded from the CA1 stratum radiatum following stimulation of the Schaffer collateral pathway. Activation of AT4 receptors by Nle1-AngIV enhanced synaptic transmission during low-frequency test pulses (0.1 Hz), and increased the level of tetanus-induced LTP by 63% over that measured under control conditions. Paired stimulation before and during infusion of Nle1-AngIV indicated no change in paired-pulse facilitation (PPF) as a result of AT4 receptor activation suggesting that the underlying mechanism(s) responsible for Nle1-AngIV-induced increase in synaptic transmission and LTP is likely a postsynaptic event. Further, applications of Nle1-Leual3-AngIV prior to, but not 15 or 30 min after, tetanization prevented stabilization of LTP. These results extend previous findings from behavioral data in that AT4 receptor agonists and antagonists are capable of activating, and inhibiting, learning and memory pathways in the hippocampus, and suggest that the AT4 receptor subtype is involved in synaptic plasticity.

Lack of association between lipaemia and central adiposity in subjects with an atherogenic lipoprotein phenotype (ALP).

OBJECTIVE: To investigate the associations between indices of adiposity and cardiovascular risk factors in individuals with an atherogenic lipoprotein phenotype (ALP). SUBJECTS: Fifty-five men, aged 34-69 y, body mass index (BMI) 22-35 kg/m2, with an ALP lipid profile (triglycerides (TG) 1.5-4.0 mmol/l, HDL<1.1 mmol/l; %LDL-3>40% total LDL). DESIGN: Each participant provided a fasting blood sample and underwent an 8 h postprandial assessment and had anthropometric measurements taken. OUTCOME MEASURES: BMI, waist circumference (W), waist-to-hip ratio (W/H), sum of skinfolds (SSK), fasting and postprandial concentrations of glucose, insulin and plasma lipids, post-heparin lipase activity, and apoE genotype. RESULTS: The expected positive associations between BMI, W and SSK and fasting and postprandial insulin were observed (r=0.42-0.65). Little association between glucose responses and any measures of adiposity was evident. Unexpectedly, there were no positive associations between measures of central adiposity (W and W/H) and fasting and postprandial TG responses, with a trend towards negative associations in this study group (TG AUC vs W, r=-0.23, P=0.097; TG IAUC vs W/H, r=-0.26, P=0.068). Subgroup analysis indicated that lack of a positive association between central adiposity and postprandial TG values was more evident in those with one E4 allele (r=-0.42, P=0.077) relative to non-E4 carriers (r=-0.16, P=0.430). The expected positive associations between insulin and TG responses were not observed (r=-0.03 to -0.36). CONCLUSION: In this ALP group the expected positive association between TG responses and a centralized distribution of body fat was not observed, particularly in individuals with an apoE4 genotype. Our findings are not in line with the view that there is a clear causal relationship between insulin resistance and the lipid abnormalities associated with ALP.

International union of pharmacology. XXIII. The angiotensin II receptors.

The cardiovascular and other actions of angiotensin II (Ang II) are mediated by AT(1) and AT(2) receptors, which are seven transmembrane glycoproteins with 30% sequence similarity. Most species express a single autosomal AT(1) gene, but two related AT(1A) and AT(1B) receptor genes are expressed in rodents. AT(1) receptors are predominantly coupled to G(q/11), and signal through phospholipases A, C, D, inositol phosphates, calcium channels, and a variety of serine/threonine and tyrosine kinases. Many AT(1)-induced growth responses are mediated by transactivation of growth factor receptors. The receptor binding sites for agonist and nonpeptide antagonist ligands have been defined. The latter compounds are as effective as angiotensin converting enzyme inhibitors in cardiovascular diseases but are better tolerated. The AT(2) receptor is expressed at high density during fetal development. It is much less abundant in adult tissues and is up-regulated in pathological conditions. Its signaling pathways include serine and tyrosine phosphatases, phospholipase A(2), nitric oxide, and cyclic guanosine monophosphate. The AT(2) receptor counteracts several of the growth responses initiated by the AT(1) and growth factor receptors. The AT(4) receptor specifically binds Ang IV (Ang 3-8), and is located in brain and kidney. Its signaling mechanisms are unknown, but it influences local blood flow and is associated with cognitive processes and sensory and motor functions. Although AT(1) receptors mediate most of the known actions of Ang II, the AT(2) receptor contributes to the regulation of blood pressure and renal function. The development of specific nonpeptide receptor antagonists has led to major advances in the physiology, pharmacology, and therapy of the renin-angiotensin system.

ApoE polymorphism and fish oil supplementation in subjects with an atherogenic lipoprotein phenotype.

The study assessed the efficacy of fish oil supplementation in counteracting the classic dyslipidemia of the atherogenic lipoprotein phenotype (ALP). In addition, the impact of the common apolipoprotein E (apoE) polymorphism on the fasting and postprandial lipid profile and on responsiveness to the dietary intervention was established. Fifty-five ALP males (aged 34 to 69 years, body mass index 22 to 35 kg/m(2), triglyceride [TG] levels 1.5 to 4.0 mmol/L, high density lipoprotein cholesterol [HDL-C] <1.1 mmol/l, and percent low density lipoprotein [LDL]-3 >40% total LDL) completed a randomized placebo-controlled crossover trial of fish oil (3.0 g eicosapentaenoic acid/docosahexaenoic acid per day) and placebo (olive oil) capsules with the 6-week treatment arms separated by a 12-week washout period. In addition to fasting blood samples, at the end of each intervention arm, a postprandial assessment of lipid metabolism was carried out. Fish oil supplementation resulted in a reduction in fasting TG level of 35% (P<0.001), in postprandial TG response of 26% (TG area under the curve, P<0.001), and in percent LDL-3 of 26% (P<0.05). However, no change in HDL-C levels was evident (P=0.752). ANCOVA showed that baseline HDL-C levels were significantly lower in apoE4 carriers (P=0.035). The apoE genotype also had a striking impact on lipid responses to fish oil intervention. Individuals with an apoE2 allele displayed a marked reduction in postprandial incremental TG response (TG incremental area under the curve, P=0.023) and a trend toward an increase in lipoprotein lipase activity relative to non-E2 carriers. In apoE4 individuals, a significant increase in total cholesterol and a trend toward a reduction in HDL-C relative to the common homozygous E3/E3 profile was evident. Our data demonstrate the efficacy of fish oil fatty acids in counteracting the proatherogenic lipid profile of the ALP but also that the apoE genotype influences responsiveness to this dietary treatment.

Different isoforms of fasciclin II play distinct roles in the guidance of neuronal migration during insect embryogenesis.

During the formation of the enteric nervous system (ENS) of the moth Manduca sexta, identified populations of neurons and glial cells participate in precisely timed waves of migration. The cell adhesion receptor fasciclin II is expressed in the developing ENS and is required for normal migration. Previously, we identified two isoforms of Manduca fasciclin II (MFas II), a glycosyl phosphatidylinositol-linked isoform (GPI-MFas II) and a transmembrane isoform (TM-MFas II). Using RNA and antibody probes, we found that these two isoforms were expressed in cell type-specific patterns: GPI-MFas II was expressed by glial cells and newly generated neurons, while TM-MFas II was confined to differentiating neurons. The expression of each isoform also corresponded to the motile state of the different cell types: GPI-MFas II was detected on tightly adherent or slowly spreading cells, while TM-MFas II was expressed by actively migrating neurons and was localized to their most motile regions. Manipulations of each isoform in embryo culture showed that they played distinct roles: whereas GPI-MFas II acted strictly as an adhesion molecule, TM-MFas II promoted the motility of the EP cells as well as maintaining fasciculation with their pathways. These results indicate that precisely regulated patterns of isoform expression govern the functions of fasciclin II within the developing nervous system.

A randomized trial of intravaginal nonoxynol 9 versus oral metronidazole in the treatment of vaginal trichomoniasis.

OBJECTIVE: This study was undertaken to investigate the efficacy of nonoxynol 9 suppositories in the treatment of vaginal trichomoniasis. STUDY DESIGN: In this prospective comparison trial 46 women with documented motile trichomonads found on a wet preparation were randomly assigned to one of two treatment arms: (1) a single oral dose of 2 g metronidazole and (2) a single 150-mg nonoxynol 9 suppository placed intravaginally for 3 consecutive nights. Cure was determined by a repeated wet preparation examination. After its first year, the study was terminated because of the poor efficacy of the nonoxynol 9 suppositories. RESULTS: Results were available for 33 patients. Three of 17 patients treated with nonoxynol 9 had negative wet preparation results at retest (17.6% cure rate). All 16 patients treated with metronidazole had negative wet preparation results (100% cure rate). All women with nonoxynol 9 failures who were evaluated after treatment with 2 g metronidazole had negative wet preparation results. CONCLUSION: Intravaginal nonoxynol 9 at the tested dose and by the tested method of delivery was not an effective cure for vaginal trichomoniasis.

A novel angiotensin analog with subnanomolar affinity for angiotensin-converting enzyme.

This study demonstrates that a novel angiotensin I analog, angiotensinogen 3-11(Lys(11)), possesses a high affinity for angiotensin-converting enzyme (ACE), which is substantially greater than the endogenous substrates. This assessment is based on data derived from a variety of techniques. First, the binding characteristics of (125)I-angiotensinogen 3-11(Lys(11)) were examined. Equilibrium saturation isotherms utilizing guinea pig lung membranes revealed that (125)I-angiotensinogen 3-11(Lys(11)) bound a single high-affinity site in the presence of EDTA exhibiting a K(d) of 0.15 +/- 0.02 nM with a B(max) = 4295 +/- 535 fmol/mg of protein. Competition studies revealed the following rank order of binding affinity: (125)I-angiotensinogen 3-11(Lys(11)) >> bradykinin >> angiotensin I. Next, SDS-polyacrylamide gel electrophoresis analysis revealed that chemically cross-linked (125)I-angiotensinogen 3-11(Lys(11)) specifically bound a protein of M(r) 173,000 that had the same molecular weight as ACE. Utilizing in vitro autoradiography, the binding distributions of (125)I-angiotensinogen 3-11(Lys(11)) and the ACE inhibitor, (125)I-351A, were also compared. These experiments demonstrated that the binding distributions of (125)I-angiotensinogen 3-11(Lys(11)) and (125)I-351A are identical in the guinea pig lung and testes. Finally, the purification of ACE from guinea pig serum was monitored with (125)I-angiotensinogen 3-11(Lys(11)) and (125)I-351A binding. These results demonstrated that the binding site for (125)I-angiotensinogen 3-11(Lys(11)) and (125)I-351A copurified. These experiments indicate that the novel angiotensin I analog, (125)I-angiotensinogen 3-11(Lys(11)) binds to ACE and suggest that there are critical binding sites outside the catalytic domains of ACE that determine binding specificity and affinity.

Differences in glucose-dependent insulinotrophic polypeptide hormone and hepatic lipase in subjects of southern and northern Europe: implications for postprandial lipemia.

BACKGROUND: This study was an extension of a previous study that showed different lipemic responses to standard test meals in subjects from southern and northern Europe. OBJECTIVE: The aim was to determine in 32 healthy young men from northern and southern Europe whether differences in the secretion of insulin and glucose-dependent insulinotrophic polypeptide (GIP) might explain these findings through the actions of these hormones on lipoprotein lipase. DESIGN: We investigated in a randomized, single-blind, crossover study the effects of 2 test meals of identical macronutrient composition but different saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) contents on postprandial GIP, insulin, the ratio of incremental triacylglycerol to apolipoprotein B-48 (a marker of chylomicron size), and the activity of postheparin lipases. RESULTS: Fasting and postprandial GIP concentrations and postheparin hepatic lipase activities were significantly higher in the southern Europeans (P < 0.001 and P < 0.02, respectively). Lipoprotein lipase activity after the SFA-rich meal was significantly higher in the northern Europeans (P < 0.01). HL activity 9 h after the SFA-rich meal and the area under the curve (AUC) for the postprandial insulin response correlated with the AUC for the postprandial GIP response [r = 0.44 (P < 0.04) and r = 0.46 (P < 0.05), respectively]. There were no significant differences in chylomicron size between the 2 groups for either meal, but when the groups were combined there was a significant difference in chylomicron size between the SFA- and MUFA-rich meals (P < 0.05), which could be due to the formation of larger chylomicrons after the MUFA-rich meal. CONCLUSION: The significantly higher GIP and insulin responses and HL activities in southern Europeans may provide an explanation for our previous report of attenuated postprandial triacylglycerol and apolipoprotein B-48 responses in them.