Ups and downs for neuropeptides in body weight homeostasis: pharmacological potential of cocaine amphetamine regulated transcript and pre-proglucagon-derived peptides

Although most humans experience an underlying upwards drift of the body-weight set-point, body weight appears tightly regulated throughout life. The present review describes the structural basis of the adipostat and hypothesise, which components may constitute available targets for pharmacotherapy of excess body weight. Hypothalamic neurones constitute the major components of the body weight homeostasis maintaining device. Together with neurones of the nucleus of the solitary tract, neurones of the hypothalamic arcuate nucleus constitute the sensory components of the adipostat. The arcuate nucleus neurones respond to circulating levels of leptin and insulin, both of which reflect the levels of energy stored as triacylglycerol in adipocytes. The arcuate nucleus projects heavily to the hypothalamic paraventricular nucleus. Neurones of the hypothalamic paraventricular nucleus are hypothesised to constitute, at least partly, the adipostat motor pattern generator, which upon stimulation activates either net anabolic or catabolic physiological responses. The overall sensitivity of the adipostat is influenced by gain setting neurones hypothesised to be located in the dorsomedial hypothalamic nucleus and lateral hypothalamic area. Cocaine amphetamine regulated transcript (CART) peptides and pre-proglucagon derived peptides, glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2) are catabolic neurotransmitters synthesised in neurones of the arcuate nucleus and the nucleus of the solitary tract, respectively. The present review summarises the available evidence that both families of peptides constitute endogenous transmitters mediating satiety and touch upon potential pharmacological exploitation of this knowledge.

Selection of large diversities of antiidiotypic antibody fragments by phage display

Antiidiotypic antibodies (Ab2) are needed as tools for a better understanding of molecular mimicry and the immunological network, and for many potential applications in the biomedical and pharmaceutical field. Antiidiotypic antibodies mimicking carbohydrate or conformational epitopes (Ab2beta) are of considerable interest as surrogate immunogens for cancer vaccination. However, it has so far been difficult and tedious to produce Ab2s to a given antigen. Here we describe a fast and reliable technique for generating large diversities of antiidiotypic single chain antibody fragments from non-immunized phagemid libraries using phage display. Key elements are a specific elution with the original antigen followed by trypsin treatment of the eluted phages in combination with the protease sensitive helperphage KM13. This novel method was compared with various conventional selection and elution methods, including, specific elution with or without trypsin treatment, elution with glycine at pH 2.2 with or without trypsin treatment, and elution by trypsin treatment only. The results clearly show that specific elution in combination with trypsin treatment of the eluted phages is by far superior to the other conventional methods, enabling for the first time the generation of a large variety of Ab2s after only two to three rounds of selection, thereby maintaining maximum diversity. We obtained 28 to 88 antiidiotypes out of 96 tested clones after two to three rounds of selection with a diversity of 55-90 %. This was achieved for two carbohydrate (di-, and tetrasaccharides) and one conformational protein epitope using two large naïve libraries and their corresponding monoclonal Ab1. The antiidiotypic nature of the selected scFv-phages was verified by ELISA and immunocytochemistry inhibition experiments.

Applying phage display technology in aging research

Filamentous bacteriophage offers the possibility of linking genotype with phenotype in one genetic package. By creating a library of different proteins as fusion to one of the coat proteins of filamentous bacteriophage it becomes possible to isolate proteins based on their binding characteristics. Phage displayed libraries of varying formats, ranging from small peptides to antibody fragments, have been selected successfully for ligands toward a large panel of targets. These peptides and antibody fragments are applicable in analysis of the behaviour of certain proteins with respect to changes in biological processes such as aging, thus providing valuable tools for a general understanding of the aging process. Alternatively, display of antibody fragments or peptides on filamentous bacteriophage can be instrumental in the discovery of novel antigens as exemplified by selections on cell surfaces or on complex protein mixtures such as sera from aging individuals. Although phage display has been applied successfully in a large number of studies relating to cancer, viral infections and other biological processes, its application in the field of aging research is yet to be realised.

Generation and characterization of recombinant human antibodies specific for native laminin epitopes: potential application in cancer therapy

Laminins are specific cellular regulators that directly and indirectly control activities such as cell attachment and migration, differentiation and polarity, proliferation and apoptosis, and protease expression. Considering the centrality of these issues to tumor progression, the generation of human-derived antibody fragments able to modulate laminin-regulated biological functions would allow the development of new strategies to improve treatment of cancer patients. In this report, we explore the use of phage display technology to isolate human anti-laminin antibody fragments. A library of single chain antibodies was selected using intact mouse laminin, and five different clones were identified. All the antibodies were specific for their cognate antigen, as revealed by lack of cross-reactivity with other components of the basement membranes. A more extensive characterization of the panel indicated that these antibodies recognize the native protein through conformational epitopes. All of them reduced tumor cell attachment to laminin, suggesting that domains of the laminin molecule that are recognized by these antibodies likely bind to cell-surface receptors. The antibody fragments bind to mouse, rat and human laminin. and show strong immunohistochemical reactivity with basement membranes in human and murine tissue sections. Their properties make them ideal candidates for in vivo applications.

Role of mitochondria-rich cells for passive chloride transport, with a discussion of Ussing's contribution to our understanding of shunt pathways in epithelia

A non-invasive method is applied for studying ion transport by single isolated epidermal mitochondria-rich (MR) cells. MR cells of toad skin (Bufo bufo) were prepared by trypsin (or pronase) treatment of the isolated epithelium bathed in Ca2+-free Ringer. Glass pipettes were pulled and heat- polished to obtain a tip of 2-4 mm with parallel walls and low tip resistances. The neck of an MR-cell was sucked into the tip of the pipette for being 'clamped mechanically' by the heat-polished glass wall. In this configuration the apical cell membrane faces the pipette solution while the major neck region and the cell body are in the electrically grounded bath. With Ringer in bath and pipette, transcellular voltage clamp currents were composed of an ohmic (I(leak)) and a dynamic (I(dynamic)) component. The dynamic component was studied by stepping the transcellular potential (Vp) from a holding value of +50 mV to the hyperpolarizing region (50 > Vp > or = -100 mV). The steady state I(dynamic)-Vp relationship was strongly outward rectified with I(dynamic) being practically zero for Vp > 0 mV. At Vp = -100 mV, MR cells isolated by trypsin or pronase generated a steady-state I(dynamic) of,-2.72 +/- 0.40 nA/cell (N = 21 MR cells). Continuous superfusion of the MR cell during recording increased the current to -7.99 +/- 1.48 nA/cell (N = 10 MR cells). The time course of the reversible activation of G(dynamic) varied among cells, but was usually sigmoid with T1/2 decreasing with Vp (-25 > or = Vp > or = -100 mV). T1/2 was in the order of 10 sec at Vp = -100 mV. The single-MR-cell currents recorded in this study are fully compatible with Cl- currents estimated by relating density of MR cells to transepithelial ICl or by measurements with the self-referencing ('vibrating') probe technique. In the discussion, Ussing's work on epithelial shunt pathways is considered. His thinking and experiments leading to his theory of isotonic transport in leaky epithelia is emphasized. It is our thesis that the understanding of the physiology of epithelia owes as much to Ussing's studies of shunt pathways as to his studies of the active sodium pathway.

Prevalence of neuropsychiatric and mucous membrane irritation complaints among Palestinian shoe factory workers exposed to organic solvents and plastic compounds

BACKGROUND

Long-term exposure to organic solvents is associated with neuropsychiatric and mucus membrane irritation. In developing countries, efforts to secure a good working environment are inadequate and protection against chemical exposures is often neglected.

METHODS

In a cross-sectional survey, the prevalence of self-reported health complaints and the association with long-term exposure to solvents and plastic materials in the work environment was studied among 167 shoe-factory workers. Prevalences and adjusted prevalence ratios (PR)were calculated in Cox regression. 95% confidence intervals were estimated for PRs of adverse health effects.

RESULTS

Overall, the workers reported high prevalences of neuropsychiatric and mucus membrane complaints: headache (65%), mental irritability (53%), tingling of limbs (46%), and sore eyes (43%). Cleaning work was associated with tingling of limbs (PR = 1.8, 1.0-3.2), sore eyes (PR = 1.9, 1.1-3.3), and breathing difficulty (PR = 2.0, 1.0-3.9); plastic work was associated with tingling of limbs (PR = 1.8, 1.2-2.9)and sore eyes (PR = 1.7, 1.1-2.7); and varnishing was associated with breathing difficulty (PR = 1.9, 1.1-3.5).

CONCLUSIONS

The high prevalence of self-reported health complaints and the exposure-outcome association could be due to volatile organic solvents (dichloromethane, n-hexane)and plastic compounds (isocyanates and polyvinyl chloride). Absence of a satisfactory work environment is likely to contribute to high exposure levels.

Solvent exposures at shoe factories and workshops in Hebron City, West Bank

Exposure to organic solvents has been reported to increase the risks for acute and chronic health effects among shoe industry workers. In developing countries, protection against chemical exposures is often not provided. The study was conducted to identify working conditions and estimate the concentrations of organic solvents used in shoe factories and workshops in Hebron City. Personal interviews containing questions related to personal protective equipment (PPE) were used to identify working conditions, and samples collected from factories and workshops were analyzed using gas chromatography. Geometric means (GMs) were calculated for the solvents. Six major organic solvents were detected in the factories. Acetone (GM = 51.5 mg/m3, GSD = 3.82) was common in gluing tasks. Dichloromethane (GM = 47 mg/m3, GSD = 2.62) was common in cleaning tasks. Heptane, methylethyl ketone, n-hexane, and toluene were common in gluing tasks. Four major organic solvents were detected in the workshops: acetone (GM = 32.3 mg/m:3, GSD = 6.33), toluene (GM = 70.3 mg/m3, GSD = 3.06), n-hexane (GM = 19.4 mg/m3:, GSD = 2.65), and methylethyl ketone (GM = 130 mg/mM3, GSD = 1.5). 81% of the factory workers had never used respiratory protective equipment, and 92% had never used work clothes. 97% of the workers in the workshops had never used respiratory protective equipment, 94% had never worn gloves, and 90% had never used work clothes. Exposures to solvents in the absence of personal Protective equipment, tasks barriers, and mechanical ventilation can adversely affect health.

Comparison of the decameric structure of peroxiredoxin-II by transmission electron microscopy and X-ray crystallography

The decameric human erythrocyte protein torin is identical to the thiol-specific antioxidant protein-II (TSA-II), also termed peroxiredoxin-II (Prx-II). Single particle analysis from electron micrographs of Prx-II molecules homogeneously orientated across holes in the presence of a thin film of ammonium molybdate and trehalose has facilitated the production of a >/=20 A 3-D reconstruction by angular reconstitution that emphasises the D5 symmetry of the ring-like decamer. The X-ray structure for Prx-II was fitted into the transmission electron microscopic reconstruction by molecular replacement. The surface-rendered transmission electron microscopy (TEM) reconstruction correlates well with the solvent-excluded surface of the X-ray structure of the Prx-II molecule. This provides confirmation that transmission electron microscopy of negatively stained specimens, despite limited resolution, has the potential to reveal a valid representation of surface features of protein molecules. 2-D crystallisation of the Prx-II protein on mica as part of a TEM study resulted in the formation of a p2 crystal form with parallel linear arrays of stacked rings. This latter 2-D form correlates well with that observed from the 2.7 A X-ray structure of Prx-II solved from a new orthorhombic 3-D crystal form.

Calcium-dependent association of annexins with lipid bilayers modifies gramicidin A channel parameters

In order to examine whether calcium-dependent binding of annexin to acidic phospholipids could change the lipid bilayer environment sufficiently to perturb channel-mediated transmembrane ion-transport, gramicidin A channel activity in planar lipid bilayers was investigated in the presence of calcium and annexins II, III or V. The experiments were performed with membranes consisting of phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine in 300 mM KCl solution buffered to pH 7.4 and with either 0.1 or 1 mM calcium added to the solution. Annexin (1 microM) was subsequently applied to the cis side of the membrane. All three annexins (II, III and V) when tested at 1 mM calcium decreased the gramicidin single-channel conductance. Annexins II and III increased the mean lifetime of the channels whereas annexin V seemed to have no influence on the mean lifetime. Since the lifetime of gramicidin A channels is a function of the rate constant for dissociation of the gramicidin dimer, which is dependent on the physical properties of the lipid phase, binding of annexins II and III seems to stabilize the gramicidin channel owing to a change of the bilayer structure.

Chronic intracerebroventricular administration of recombinant CART(42-89) peptide inhibits and causes weight loss in lean and obese Zucker (fa/fa) rats

OBJECTIVE

Hypothalamic neuropeptide CART (cocaine-amphetamine-regulated transcript) is a leptin-dependent endogenous satiety factor in the rat, and single central injections of recombinant CART(42-89) lowers food intake in rats and mice. To assess the potential role of CART as a long-term regulator of food intake, we investigated the effects of continuous infusion of recombinant CART(42-89) on food consumption and body weight.

RESEARCH METHODS AND PROCEDURES

Two doses of CART(42-89) were tested: 12 or 4.8 microg/d. Adult male, both lean (+/?) and Zucker (fa/fa) obese, rats were equipped with intracerebroventricular cannulae in the right lateral ventricle. The cannulae were connected to subcutaneously placed osmotic mini-pumps. Pumps were filled with either CART(42-89) or vehicle (50 mM phosphate-buffered saline, pH 7.4). The pumps delivered a continuous infusion of CART(42-89) or vehicle, and food intake and body weight were followed for 10 days (12 microg/d) or 7 days (4.8 microg/d). Animals given the low dose had the pump removed on Day 7, and from half of the group, trunk blood was collected after decapitation, whereas the other half of the group had their mini-pumps removed and were followed for another 7 days before being decapitated.

RESULTS

Animals receiving the high doses displayed overt motor disturbances, whereas the low dose was devoid of such behavioral side effects. Both doses significantly lowered food intake with maximal effect on days 3 to 5 of the infusion period. The high dose of CART decreased body weight of normal animals to 85% of initial weight at days 3 to 5, whereas the weight of Zucker (fa/fa) obese rats dropped to 95% of the initial weight. In animals receiving 4.8 microg/d, moderate effects on body weight were seen between days 4 and 6 of the treatment period, but soon after termination of the treatment animals regained lost weight. To assess the biological activity of the contents of the osmotic mini-pumps, the pumps were removed from the subcutaneous implantation site, and 5 microL of their contents were injected intracerebroventricularly to naive animals kept on a restricted feeding schedule. The content of pumps from animals receiving 4.8 microg/d of CART(42-89) potently inhibited food intake, confirming full biological activity despite being kept for 7 days at body temperature.

DISCUSSION

Due to obvious effects on motor behavior, it is impossible with certainty to conclude that the observed effects on feeding and body weight are primary interference with satiety centers or secondary to effects on locomotor pathways. Also, the present experiments suggest that hypothalamic appetite-regulating neurons are subject to pharmacological desensitization upon prolonged exposure to CART peptide. The underlying mechanism of such desensitization is as yet unknown.

Hormone-dependent cancer and adverse reproductive outcomes in farmers' families--effects of climatic conditions favoring fungal growth in grain

OBJECTIVES

The impact of grain farming and climate on late-term abortion among female farmers, male genital birth defects among their sons, and hormone-dependent cancer among male and female farmers and their adult children was investigated.

METHODS

National registers were cross-matched in Norway and 246,043 male and female farmers born in 1925-1971 were identified, as were their 264,262 children, born in 1952-1980, in agricultural censuses and in the population register. The subjects were followed in the Cancer Register through 1995. Farmers' births, conceived in 1973-1991, were identified, and the prevalences of late-term abortion in mothers and hypospadias and cryptorchidism in their sons at birth were examined. Exposure, defined as the combination of grain farming and categories of seasonal or cumulative warnings, was based on data in agricultural censuses and on local, seasonal, field fungal warnings. Estimated adjusted rate ratios or prevalence ratios served as the measures of association.

RESULTS

Categories of high exposure were associated with reproductive outcomes and cancer among female farmers, the strongest occurring for late-term abortion (ratio 2.6, 95% confidence interval (95% CI) 1.6-4.3). Exposure associations for ovarian and breast cancer, and male genital defects, were more moderate. Endometrial cancer was associated with grain farming (ratio 2.0, 95% CI 1.4-2.8) across all levels of fungal warnings. Exposure associations for cancer were strongest for premenopausal, parous women. Exposure was not associated with cancer among male farmers or children.

CONCLUSIONS

Climatic conditions favoring fungal growth in grain were associated with hormone-dependent adverse outcomes among female farmers; the results are consistent with hormonal effects of inhaled mycotoxins during pregnancy.

Implementing clinical guidelines in the treatment of diabetes mellitus in general practice. Evaluation of effort, process, and patient outcome related to implementation of a computer-based decision support system

OBJECTIVES

To evaluate the implementation of clinical guidelines for diabetes mellitus in general practice with a specific computer-based clinical decision support system (CDSS) as part of the intervention.

METHODS

Randomized study with health center as unit. General practice in Sør- and Nord-Trøndelag counties in Norway, 380,000 inhabitants. Seventeen health centers with 24 doctors and 499 patients with diabetes mellitus were in the intervention group and 12 health centers with 29 doctors and 535 patients were in the control group. Main outcome measures were group differences in fractions of patients without registrations (process evaluation) and mean group differences for the same variables (patient outcome evaluation).

RESULTS

Statistically significant group differences were experienced for fractions of patients without registration of cigarette smoking (intervention group, 82.6%; control group 94.5%), body mass index (78.2% vs. 93.0%), and sufficient registrations for calculation of risk score for myocardial infarction (91.1% vs. 98.3%); all during 18 months. Large center variations were shown for all variables. The only statistically significant group difference was -2.3 mm Hg (95% CI, -3.8, -0.8) in diastolic blood pressure in favor of the intervention group. Statistically insignificant differences in favor of the intervention group were HbA1c, -0.1% (95% CI, -0.4, 0.1), systolic blood pressure, -1.2 mm Hg (95% CI, -4.4, 2.0). Statistically insignificant differences in favor of the control group were fractions of smokers, +3.0% (95% CI, -4.0, 10.0), body mass index, +0.3 kg/m2 (95% CI, -0.8, 1.4), risk score in female +0.1 (95% CI, -5.1, 5.2), and risk score in male +2.6 (95% CI, -14.2, 19.5).

CONCLUSIONS

Implementation of clinical guidelines for diabetes mellitus in general practice, by means of a CDSS and several procedures for implementation, did not result in a clinically significant change in doctors' behavior or in patient outcome.

Maternal reproductive history: a registry based comparison of previous pregnancy data derived from maternal recall and data obtained during the actual pregnancy

OBJECTIVE

To compare the quality of data on previous pregnancies, based on maternal recall, to that of actual data in previous birth records, and to quantify to which extent recall based data bias results in epidemiologic studies on adverse reproductive outcomes.

METHODS

Through linkage between agricultural censuses and the Medical Birth Registry, we identified 87,113 Norwegian female farmers with 174,764 single births in 1967-1991, including 533 late abortions (16-27 weeks). Data were linked into sibship records. In routine birth records, mothers provide information at each birth on previous fetal loss. Thus, we had information both based on recall and on the actual record.

RESULTS

Among all mothers with a loss documented in previous records, 73.5% had a recall of previous loss (sensitivity), while 74.3% of all mothers reporting a previous loss also had a loss in previous sibship records (positive predictive value). Late abortion after a previous loss according to the sibship record was more frequent than after a previous loss based on maternal recall (18.3 vs. 10.8 per 1,000). There was a particular lack of recall for previous losses of short gestational age or when the current birth was a late abortion; both conditions tended to deflate the association between a previous and a current adverse outcome. Grain farming was associated with late abortion in mothers with previous loss in sibship records (odds ratio, 2.6) but not among mothers without previous loss (odds ratio, 1.0). When information on previous loss was based on maternal recall the odds ratios were 1.4 and 1.3, respectively.

CONCLUSIONS

Consecutive sibship records give more valid information than data derived from maternal recall.

Prevalence of self-reported health complaints among shoe workers of small workshop exposed to organic solvents in Hebron City, West Bank: a cross-sectional survey

The study was conducted to estimate the prevalences of neurological disorders and mucous membrane irritation complaints among workers of shoe workshops in Hebron City, in particular to measure the associations between the occurrence of symptoms indicating polyneuropathy among workers and exposure to organic solvents in the glueing tasks. A group of 103 male workers from 30 workshops, exposed to organic solvents for more than one year were recruited to the study during the years 1996-1997. A validated Swedish neuropsychiatric questionnaire which contained questions on neurological and mucous irritation symptoms was used. Prevalence ratios were used as an indicator for relative risk. The overall prevalence of painful tingling of limbs (used as indicator of polyneuropathy) was high among the workshop workers (40%) and was significantly associated with long term exposure to organic solvents in glueing tasks (PR 2.8: 95% CI 1.0-8.3). Moderate associations were seen in other tasks. Headache and mental irritability did not show any association with organic solvent exposure in the workshop tasks. Breathing difficulty showed a moderate non-significant association with long term exposure to organic solvents (72 months) in cleaning tasks (1.9,0.7-4.8), while sore eyes also showed a moderate non-significant association with exposure to organic solvents for 25-72 months in the glueing tasks. Long term exposure to n-hexane (mainly found in the glues) could be the main cause of polyneuropathy among the workers of Hebron shoe workshops. The absence of effective ventilation systems and personal protective equipment might increase the prevalence of polyneuropathy among these workers. In conclusion, glues containing high concentrations of n-hexane are still in use in many shoe workshops in Hebron City (as well as in other developing countries), and long term exposure to n-hexane in glueing compounds could result in polyneuropathy among the workers. However, in the absence of objective measurements our results must be interpreted with caution. Well planned longitudinal studies with objective measures of exposure and disease are important for future research in developing countries.

Central administration of cocaine-amphetamine-regulated transcript activates hypothalamic neuroendocrine neurons in the rat

We have recently shown that intracerebroventricular (i.c.v.) administration of the hypothalamic neuropeptide cocaine-amphetamine-regulated transcript (CART) inhibits food intake and induces the expression of c-fos in several nuclei involved in the regulation of food intake. A high number of CART-induced c-Fos-positive nuclei in the paraventricular nucleus of the hypothalamus prompted us to examine the effect of i.c.v. recombinant CART-(42-89) on activation of CRH-, oxytocin-, and vasopressin-synthesizing neuroendocrine cells in the paraventricular nucleus (PVN). In addition, plasma levels of glucose were examined after central administration of CART-(42-89). Seventy-six male Wistar rats were fitted with i.c.v. cannulas and singly housed under 12-h light, 12-h dark conditions. One week postsurgery the animals were injected i.c.v. in the morning with 0.5 microg recombinant CART-(42-89) or saline. Trunk blood was collected by decapitation at 0 (baseline), 10, 20, 40, 60, 120, or 240 min. CART caused a strong increase in circulating corticosterone that was significantly different from saline at 20, 40, 60, and 120 min postinjection (P<0.05). Furthermore, CART caused a transient rise in plasma oxytocin levels (P<0.05 at 10 and 20 min postinjection), whereas plasma vasopressin levels were unaffected by i.c.v. CART. Animals injected i.c.v. with CART showed a rise in blood glucose levels 10 min postinjection (P<0.05). To examine whether the stimulatory effect of i.c.v. CART on corticosterone and oxytocin secretion is caused by activation of paraventricular nucleus/supraoptic nucleus (PVN/SON) neuroendocrine neurons, we used c-Fos as a marker of neuronal activity. Animals injected with CART showed a strong increase in c-Fos-immunoreactive nuclei in the PVN. Double immunohistochemistry revealed that a high (89+/-0.4%) number of CRH-immunoreactive neurons in the PVN contained c-Fos after CART i.c.v.. c-Fos expression was also observed in oxytocinergic cells (in both magnocellular and parvicellular PVN neurons as well as in the supraoptic nuclei) 120 min after CART administration, whereas none of the vasopressinergic neurons contained c-Fos. Triple immunofluorescence microscopy revealed that CART-immunoreactive fibers closely apposed c-Fos-positive CRH neurons, suggestive of a direct action of CART on PVN CRH neurons. In summary, i.c.v. CART activates central CRH neurons as well as both magnocellular (presumably neurohypophysial) and parvicellular (presumably descending) oxytocinergic neurons of the PVN. The effect of CART on CRH neurons most likely leads to corticosterone secretion from the adrenal gland, which may contribute to the inhibitory effects of CART on feeding behavior.

Identification of phage antibodies toward the Werner protein by selection on Western blots

A procedure was established for selecting phage antibodies (phage-abs) from phage-displayed antibody repertoires by panning against proteins, separated by sodium dodecyl phosphate-polyacrylamide gel electrophoresis (SDS-PAGE) and electroblotted onto nitrocellulose membranes (Western blots). This immobilization strategy is applicable for secondary rounds of panning in selections against semipurified proteins, and directs the selection toward antibodies suitable as immunochemical reagents in Western blots. In model experiments, enrichment factors as high as 1.9x10(5) were obtained in a single round of panning. Furthermore, we demonstrate the application of this approach by selection of phage-abs recognizing the human Werner protein, which is defective in a premature aging syndrome.

Parental exposure, adverse pregnancy and offspring effects--perspectives in developmental epidemiology

Developmental health is governed by biology and the societal culture that shapes family planning. This context should not be ignored in epidemiologic studies that address the effect of parental exposure from environmental and occupational agents on prenatal development, growth and survival, on adverse birth effects, or on postnatal events. It is important to have a thorough basic knowledge of developmental health in the population under study and to consider this basis in study design and performance. One way of accomplishing this task is to combine strengths of population-based cohort studies and nested case-control studies. Sibship-based cohorts and case-control studies that make use of biomarkers may provide particular advantages. Future research on the impact of parental exposure should be more strongly based on biological knowledge about the genetic, immune, and endocrine regulation of prenatal growth and development.

Exposure scenarios and guidance values for urban soil pollutants

In general, risk assessments of urban soil pollution are prepared by comparing the levels of pollutants with soil quality criteria. However, large urban areas are contaminated with concentrations of pollutants far exceeding the existing soil quality criteria and would consequently be considered to be of potential risk to humans. This is, however, a rather rigid approach, and for risk management purposes it would be desirable to have more than just one level of soil quality criteria. Therefore, a generic risk assessment model was developed for five different use scenarios: child-care centers, kitchen gardens, ornamental gardens, parks, and sports grounds. In each of the scenarios, three different types of expected behavior are described for children and adults, respectively, resulting in different levels of exposure to the pollutants. For risk management purposes, various guidance values can then be derived for each use scenario. Below a lower guidance value, a free use of the area according to the defined use is possible without an unacceptable risk to the public. Above an upper value, a cutoff of the exposure is necessary. In between, the use may be regulated by different types of advice. The model is still preliminary but was, however, used for derivation of guidance values for five commonly found soil pollutants, of which the results for benzo[a]pyrene and lead are presented.

Co-localization of growth hormone secretagogue receptor and NPY mRNA in the arcuate nucleus of the rat

Growth hormone secretagogues (GHS) are small, synthetic compounds which have the potential of releasing growth hormone (GH) from the pituitary. The mechanism of action of GHS has not been fully elucidated. A specific GHS receptor (GHS-R) is expressed in the pituitary gland and in several areas of the brain including the hypothalamus. We have characterized the GHS-R-mRNA-expressing neurons with respect to co-expression of selected neurotransmitters in the hypothalamus. This was done by dual chromogenic and autoradiographic in situ hybridization with riboprobes for GHS-R mRNA and neuropeptide Y (NPY), pro-opiomelanocortin (POMC), somatostatin (SRIH) or GH-releasing hormone (GHRH) mRNA. In the arcuate nucleus, GHS-R mRNA was expressed in 94 +/- 1% of the neurons expressing NPY, 8 +/- 2% of those expressing POMC and 30 +/- 6% expressing SRIH mRNA. 20-25% of the GHRH- mRNA-expressing neurons contained GHS-R mRNA, whereas the vast majority of the arcuate GHS-R-mRNA-containing cells did not contain GHRH mRNA. The finding of a significant co-expression of GHS-R and NPY mRNA in the arcuate nucleus is in accordance with the previous demonstration by Dickson et al. that c-Fos is induced in NPY neurons following GHS administration. These results indicate that GHS have other effects on neuroendocrine regulation than GH release via GHRH neurons. Stimulation of the arcuate NPY neurons via GHS-R may explain the increased appetite and the cortisol release seen after administration of some GHS compounds.

Properties of thiol-specific anti-oxidant protein or calpromotin in solution

We have isolated calpromotin, a protein reported abundant in human red cells and shown to be of significance for KCl transport. We show that calpromotin is identical to a radical scavenger protein, thiol-specific antioxidant protein (TSA). Calpromotin is known to exist partially as a large complex of identical subunits and partially as dimers probably held together by disulfide bridges. The stability of the high-molecular-weight form was studied by variations of pH and urea concentration. It is shown that the equilibrium between the large complex and the dimeric subunit is governed by the dissociation of a group with a pK value of about 7.5. Dissociation of the complex was also complete at 2.5 M urea, where no unfolding of the peptide chains was detectable.

Neurochemical characterization of hypothalamic cocaine- amphetamine-regulated transcript neurons

The novel neuropeptide cocaine-amphetamine-regulated transcript (CART) is expressed in several hypothalamic regions and has recently been shown to be involved in the central control of food intake. To characterize the hypothalamic CART neurons and understand the physiological functions they might serve, we undertook an in situ hybridization and immunohistochemical study to examine distribution and neurochemical phenotype of these neurons. In situ hybridization studies showed abundant CART mRNA in the periventricular nucleus (PeV), the paraventricular nucleus of the hypothalamus (PVN), the supraoptic nucleus (SON), the arcuate nucleus (Arc), the zona incerta, and the lateral hypothalamic area. The distribution of CART-immunoreactive neurons as revealed by a monoclonal antibody raised against CART(41-89) displayed complete overlap with CART mRNA. Double immunohistochemistry showed co-existence of CART immunoreactivity (CART-IR) and somatostatin in some neurons of the PeV. In the magnocellular division of the PVN as well as the SON, CART-IR was demonstrated in both oxytocinergic and vasopressinergic perikarya. In the medial parvicellular region of the PVN a few CART-IR neurons co-localized galanin, but none was found to co-localize corticotropin-releasing hormone. In the Arc, almost all pro-opiomelanocortinergic neurons were shown to contain CART, whereas no co-localization of CART with NPY was found. In the lateral hypothalamic area nearly all CART neurons were found to contain melanin-concentrating hormone. The present data support a role for CART in neuroendocrine regulation. Most interestingly, CART is co-stored with neurotransmitters having both positive (melanin-concentrating hormone) as well as a negative (pro-opiomelanocortin) effect on food intake and energy balance.

The hypothalamic satiety peptide CART is expressed in anorectic and non-anorectic pancreatic islet tumors and in the normal islet of Langerhans

The hypothalamic satiety peptide CART (cocaine and amphetamine regulated transcript) is expressed at high levels in anorectic rat glucagonomas but not in hypoglycemic insulinomas. However, a non-anorectic metastasis derived from the glucagonoma retained high CART expression levels and produced circulating CART levels comparable to that of the anorectic tumors. Moreover, distinct glucagonoma lines derived by stable HES-1 transfection of the insulinoma caused severe anorexia but retained low circulating levels of CART comparable to that of insulinoma bearing or control rats. Islet tumor associated anorexia and circulating CART levels are thus not correlated, and in line with this peripheral administration of CART (5-50 mg/kg) produced no effect on feeding behavior. In the rat two alternatively spliced forms of CART mRNA exist and quantitative PCR revealed expression of both forms in the hypothalamus, in the different islet tumors, and in the islets of Langerhans. Immunocytochemistry as well as in situ hybridization localized CART expression to the somatostatin producing islet D cell. A potential endocrine/paracrine role of islet CART remains to be clarified.

Tissue-specific processing of cocaine- and amphetamine-regulated transcript peptides in the rat

Cocaine- and amphetamine-regulated transcript (CART) is a recently discovered hypothalamic peptide regulated by leptin and with a potent appetite-suppressing activity. In the rat, the CART gene encodes a peptide of 116 amino acid residues (or a splice variant 13 residues longer). The predicted signal sequence is 27 amino acid residues, resulting in a prohormone of 89 residues. The CART prohormone contains several potential posttranslational processing sites in the form of mono- and dibasic sequences. In the present study we have purified CART peptides from extracts of adrenal gland, hypothalamus, nucleus accumbens, and pituitary gland (anterior and neurointermediate lobe) of the rat and determined the peptide structures by using microsequencing and mass spectrometry. In none of the tissues examined the long splice variant was found. From the adrenal gland, the CART(1-89) and CART(10-89) peptides were isolated, in contrast to the hypothalamus and nucleus accumbens, from which the shorter form peptides CART(42-89) and CART(49-89) were purified. From the anterior lobe of the pituitary gland, CART(42-89) was isolated, in contrast to the neurointermediate lobe, which contains only CART(49-89). This tissue-specific processing indicates that CART peptides may have different biological functions in the periphery and in the central nervous system.

Identical subunit topographies of human and yeast 20S proteasomes

The arrangement of subunits in human 20S proteasomes was recently determined by us by immunoelectron microscopy and chemical cross-linking. The positions of 4 of the 14 subunits differed from those found in the yeast proteasome by X-ray crystallography. Double labeling of human 20S proteasomes with antibodies to subunits C2 and C5 has now shown that these subunits are nearest neighbors. The result contradicts our published model for the human proteasome but is in accordance with the subunit arrangement in yeast proteasomes, suggesting that yeast and human proteasomes most probably have identical subunit arrangements. Immunoelectron microscopy also showed that the C-terminal extension at the human C2 subunit is flexible but takes up a well-defined position in the proteasome.

Recombinant CART peptide induces c-Fos expression in central areas involved in control of feeding behaviour

We have recently shown that the hypothalamic neuropeptide CART (cocaine-amphetamine-regulated-transcript) is a leptin dependent endogenous satiety factor in the rat. In the present study we confirm and extend our previous observations by showing that intracerebroventricular (i.c.v.) administered CART(42-89) dose-dependently inhibits 3-h food intake in food restricted rats with a lowest effective dose of 0.5 microgram. CART also potently inhibits NPY-induced food intake in satiated rats as well as nighttime food intake in free feeding animals. To identify brain areas potentially involved in mediating the anorectic effects of CART, the temporal expression pattern of the immediate early gene c-fos was examined in the central nervous system by immunohistochemistry in rats receiving recombinant CART. Compared to vehicle, CART induced c-Fos expression in several hypothalamic and brainstem structures implicated in the central control of food intake. In the hypothalamus, high numbers of c-Fos immunoreactive (-ir) cells were observed in the medial parvocellular part of the paraventricular nucleus and in the posterior part of the dorsomedial nucleus. Lower numbers of c-Fos positive nuclei were found in the supraoptic and arcuate nuclei. A relatively high number of c-Fos-ir cells was found in the central nucleus of the amygdala. In the brainstem, c-Fos-positive nuclei were found in the parabrachial nucleus, and in the nucleus of the solitary tract. Notably both the area postrema and the dorsal motor nucleus of the vagus were virtually devoid of c-Fos-ir cells. The present experiments suggest that CART peptide exerts its inhibitory effects on appetite by activating hypothalamic and brainstem neurones implicated in the central control of feeding behaviour and metabolism.

CART, a new anorectic peptide

Cocaine and amphetamine regulated transcript peptide (CART), is a recently discovered hypothalamic peptide with a potent appetite suppressing activity. In the rat the CART gene encodes a peptide of either 129 or 116 amino acid residues whereas only the short form exists in humans. The predicted signal sequence is 27 amino acid residues resulting in a prohormone of 102 or 89 residues. The C-terminal end of CART, consisting of 48 amino acid residues and 3 disulphide bonds, is thought to constitute a biologically active part of the molecule. In the central nervous system CART is highly expressed in many hypothalamic nuclei, some of which are involved in regulating feeding behaviour. The CART mRNA is regulated by leptin, and the expressed CART is a potent inhibitor of feeding that even overrides the feeding response induced by neuropeptide Y. The putative CART receptor is therefore a potential therapeutic target for an anti-obesity drug.

Proteolytic selection for protein folding using filamentous bacteriophages

BACKGROUND

Filamentous bacteriophages have been used for the selection of folded peptide and protein 'ligands' by binding the phage to 'receptor'-coated solid phase. Here, using proteolysis, we have developed a technique for the selection of folded and stable proteins that is independent of their binding activities.

RESULTS

When a 21-residue peptide comprising a protease cleavage site was introduced into the flexible linker between the second and third domains of the minor coat protein p3 of filamentous bacteriophage, the phages could be cleaved by trypsin and were rendered non-infective. By contrast, phages displaying mutant barnases at this site were resistant to proteolysis, but were cleaved and their infectivity was destroyed as the temperature was raised. By mixing phages bearing two barnase mutants of differing stability, and adding protease at a temperature at which one mutant was resistant and the other was sensitive, we were able to enrich by 1.6 x 10(4)-fold for phages bearing the more stable barnase.

CONCLUSIONS

The approach provides a means for the selection of folded and stable proteins, and may be applicable to the selection of de novo proteins.

Central administration of Y5 receptor antisense decreases spontaneous food intake and attenuates feeding in response to exogenous neuropeptide Y

A number of neuropeptide Y (NPY) receptor subtypes, including the recently cloned Y5 receptor, have been implicated in the stimulation of food intake. In the present study, Y5 receptor antisense oligodeoxynucleotides (ODNs) were used to assess the potential involvement of the Y5 receptor in the regulation of spontaneous as well as NPY-induced food intake. Repeated central administration of Y5 antisense ODN significantly decreased spontaneous food intake and subsequently resulted in a significant weight loss. Furthermore, Y5 antisense ODN pre-treatment significantly inhibited the robust feeding response elicited by central administration of NPY (5.3+/-0. 8 vs 1.08+/-0.28 g, vehicle+/-s.e.m. vs Y5 ODN+/-s.e.m.). The present results provide evidence that central Y5 receptors are involved in both spontaneous as well as NPY-induced food intake, which may prove to be a new therapeutic route in the treatment of obesity and other disorders of appetite.

Implementing clinical guidelines in the treatment of hypertension in general practice

Discrepancies between clinical guidelines and clinical practice call for practical implementation strategies. This study evaluates the implementation of clinical guidelines for hypertension in general practice with a specific computer-based clinical decision support system (CDSS) as part of the intervention. We carried out a randomized study of general practice health centres in Sør- and Nord-Trøndelag counties in Norway (population 380000). A total of 17 health centres were included, with 24 doctors and 984 patients in the intervention group. Data from 887 patients was used in the analyses. There were 12 health centres with 29 doctors and 1255 patients in the control group. Data from 1127 control patients was used in the analyses. The main outcome measures were doctor's behaviour, measured by adherence to registration of recommended variables in the Norwegian clinical guidelines for hypertension. The aim of the intervention was to lower the fractions of patients without registrations. However, there were no clinically significant differences between the intervention group and the control group for fractions of patients without registration of blood pressure (intervention group 14.3%, control group 14.2%) or serum cholesterol (62.3% vs. 56.8%) during 12 months, nor, during 18 months, for fractions of patients without a registration of cigarette smoking (82.9% vs. 87.1%), cardiovascular inheritance (79.5% vs. 73.4%) and body mass index (81.5% vs. 89.2%). One or several variables necessary for calculation of risk score for myocardial infarction were missing in 91.7% of patients in the intervention group and 91.9% of patients in the control group. Large centre variations were shown for all variables. Implementation of clinical guidelines in the treatment of hypertensive patients in general practice, by means of a CDSS and several procedures for implementation did not result in clinically significant changes in the doctors' behaviour. Of importance are both the lack of user-friendliness of the specific CDSS and problems in performing time-consuming multidimensional procedures.

Muscarinic agonists exhibit functional dopamine antagonism in unilaterally 6-OHDA lesioned rats

(5R,6R) 6-(3-propylthio-1,2,5-thiadiazol-4-yl)-1-azabicyclo[3.2.1]oc tane (PTAC) is a selective muscarinic ligand with high affinity for central muscarinic receptors, agonist mode of action at the muscarinic M2 and M4 receptor subtypes and substantially less or no affinity for central dopamine receptors. In the present study PTAC, as well as the muscarinic agonists oxotremorine, RS86 and pilocarpine, inhibited dopamine D1 and D2 receptor agonist induced contralateral rotation in unilaterally 6-OHDA lesioned rats. The dose of SKF 38393 used to induce contralateral rotation also caused an intense Fos protein immunoreactivity in the rat dorsolateral striatum on the lesioned site which was inhibited by PTAC indicating that the inhibition of rotation by PTAC was not due to non-specific peripheral side effects.

Distribution of neuropeptide Y receptor expression in the rat suprachiasmatic nucleus

Neurones of the suprachiasmatic nucleus constitute the mammalian circadian clock which receives photic information via the retino-hypothalamic tract and to some extent non-photic information via the geniculo-hypothalamic tract. The majority of neurones in the geniculo-hypothalamic tract contains neuropeptide Y and both in vitro and in vivo physiological experiments have demonstrated that neuropeptide Y administered directly into the suprachiasmatic nucleus has the capacity to phase-shift the endogenous circadian rhythm of these neurones. The recent cloning of multiple mammalian neuropeptide Y receptors enabled us to perform an in situ hybridization histochemical study identifying expression of distinct neuropeptide Y receptor encoding mRNAs in the suprachiasmatic nucleus. It was seen that Y1 and Y5 receptor mRNA is highly expressed in neurones of the ventrolateral portion of the suprachiasmatic nucleus while neither Y2 nor Y4 receptor mRNA could be detected in the nucleus. These experiments demonstrate that post-synaptic neuropeptide Y mediated events in the suprachiasmatic nucleus are likely to be mediated by either of these receptors.

Hypothalamic CART is a new anorectic peptide regulated by leptin

The mammalian hypothalamus strongly influences ingestive behaviour through several different signalling molecules and receptor systems. Here we show that CART (cocaine- and amphetamine-regulated transcript), a brain-located peptide, is a satiety factor and is closely associated with the actions of two important regulators of food intake, leptin and neuropeptide Y. Food-deprived animals show a pronounced decrease in expression of CART messenger RNA in the arcuate nucleus. In animal models of obesity with disrupted leptin signalling, CART mRNA is almost absent from the arcuate nucleus. Peripheral administration of leptin to obese mice stimulates CART mRNA expression. When injected intracerebroventricularly into rats, recombinant CART peptide inhibits both normal and starvation-induced feeding, and completely blocks the feeding response induced by neuropeptide Y. An antiserum against CART increases feeding in normal rats, indicating that CART may be an endogenous inhibitor of food intake in normal animals.

Purification and characterisation of a tissue specific elongation factor 1 alpha (EF-1 alpha 2) from rabbit muscle

The peptide elongation factor 1 alpha (EF-1 alpha) has been isolated and characterised from a number of species. Recently we and others have reported the existence of an isoform of the ubiquitously expressed EF-1 alpha mRNA in higher eukaryotes, including human cells. This isoform has a tissue specific expression pattern, confining it primarily to muscle, heart, and brain. In the present study we have purified the isoform of EF-1 alpha from rabbit muscle. Using partial amino acid analysis, we can conclude that in rabbit muscle essentially only the isoform of elongation factor 1 alpha, designated EF-1 alpha 2, is translated. Preliminary activity assays show that the isoform has the same functional activities as the normal EF-1 alpha, designated EF-1 alpha 1, in relation to protein synthesis, but may behave differently in the ability to bind nucleotides. Based on the availability of the isoforms of EF-1 alpha purified from a mammalian species, it will be possible to conduct further comparative studies in order to elucidate the different functions of EF-1 alpha 1 and EF-1 alpha 2 proteins.

The elongation factor 1 A-2 isoform from rabbit: cloning of the cDNA and characterization of the protein

Eukaryotic elongation factor 1 A (eEF1A, formerly elongation factor-1 alpha) is an important component of the protein synthesis apparatus. Here we report the isolation and characterization of the cDNA sequence encoding rabbit eEF1A-2, an isoform of eEF1A, as well as a structural and functional comparison of the two rabbit isoforms. Northern analysis of the expression pattern of eEF1A-2 showed that this isoform is expressed in skeletal muscle, heart, brain and aorta, while transcripts are not detected in liver, kidney, spleen and lung. In contrast, the previously characterized eEF1A-1 isoform is expressed in all tissues examined except skeletal muscle. We have recently purified eEF1A-2 from rabbit skeletal muscle. By partial amino acid sequencing and determination of the post-translational modifications of eEF1A-2 we found that both of the glycerylphosphorylethanolamine modifications observed in eEF1A-1 appear to be present in eEF1A-2. However, two of the residues found dimethylated in eEF1A-1 appeared to be trimethylated in eEF1A-2. A comparison of the enzymatic activity showed that eEF1A-1 and eEF1A-2 have indistinguishable activity in an in vitro translation system. In contrast, the GDP dissociation rate constant is approximately 7 times higher for eEF1A-1 than for eEF1A-2. The nucleotide preference ratio (GDP/GTP) for eEF1A-1 was 0.82, while the preference ratio for eEF1A-2 was 1.50.

Proteoglycan expression in the normal rat kidney

Proteoglycans constitute a heterogenous group of complex macromolecules, consisting of a backbone core protein and a variable number of sulfated polysaccharide side chains covalently linked to the core. A dual function for these polyanionic glycosaminoglycans in kidney physiology has been proposed: to maintain a fixed negative charge in the glomerular filtration barrier, and to bind and sequester cytokines essential for renal development and function. With the aim of identifying proteoglycan genes expressed in kidney glomeruli, we have performed in situ hybridization for selected proteoglycan core proteins in the normal rat kidney. Syndecan-4, glypican-1 and biglycan were all expressed in normal glomeruli, whereas syndecan-1, perlecan and versican mRNAs were confined to the papillary area. Decorin mRNA was detected in interstitial cells found between tubuli and surrounding larger vessels. No signal for betaglycan mRNA could be detected. By hybridizing adjacent sections with a probe for the podocyte-specific PTPase GLEPP-1, the glomerular cells containing mRNA for syndecan-4 and glypican-1 could be identified as podocytes, whereas the cells expressing biglycan were identified as mesangial cells. These results demonstrate that seven out of the eight proteoglycans investigated are expressed in the normal kidney in detectable amounts and, importantly, that each proteoglycan gene shows a unique pattern of expression. The constitutive expression of syndecan-4, glypican-1 and biglycan in glomerular cells points to a role for these polyanionic molecules in maintaining the integrity of the glomerular filtration barrier.

Birth defects among offspring of Norwegian farmers, 1967-1991

We investigated birth defects (N = 4,565) reported to the Medical Birth Registry of Norway among 192,417 births between 1967 and 1991 to parents identified as farmers in five agricultural and horticultural censuses between 1969 and 1989. The prevalences at birth of all and specific birth defects deviated little from those among 61,351 births to non-farmers in agricultural municipalities. We classified exposure indicators on the basis of information provided at the agricultural censuses. The main hypotheses were that parental exposure to pesticides was associated with defects of the central nervous system, orofacial clefts, some male genital defects, and limb reduction defects. We found moderate increases in risk for spina bifida and hydrocephaly, the associations being strongest for exposure to pesticides in orchards or greenhouses [spina bifida: 5 exposed cases, odds ratio (OR) = 2.76, 95% confidence interval (CI) = 1.07-7.13; hydrocephaly: 5 exposed cases, OR = 3.49, 95% CI = 1.34-9.09]. Exposure to pesticides, in particular in grain farming, was also associated with limb reduction defects (OR = 2.50; 95% CI = 1.06-5.90). We also saw an association with pesticides for cryptorchism and hypospadias. We found less striking associations for other specific defects and pesticide indicators, animal farming, and fertilizer regimens.

Gestational age, birth weight, and perinatal death among births to Norwegian farmers, 1967-1991

Perinatal health was investigated by linkage with the Medical Birth Registry of Norway for 192,417 births that took place between 1967 and 1991 among parents identified as farm holders in Norwegian agricultural censuses in 1969-1989. In a comparison with 61,351 births to nonfarmers in agricultural municipalities, farmers' births had an advantageous distribution of gestational ages and birth weights. Perinatal mortality was similar in the two groups, but the proportion of late-term abortions (gestational weeks 16-27) was higher among farmers' birth (odds ratio (OR) = 1.9, 95% confidence interval (CI) 1.6-2.3). Exposure indicators were classified on the basis of information given in the agricultural censuses and climate data for the grain harvest seasons of 1966-1991. The main hypotheses were that perinatal death is associated with parental exposure to pesticides. Toxoplasma contracted from infected sheep or pigs, or mycotoxins found in grain farming. There was no convincing evidence that perinatal death is associated with use of pesticides, sheep farming, or pig farming. The increase in late-term abortion among the farmers could to some extent be attributed to an excess of midpregnancy (weeks 21-24) deliveries among grain farmers; grain farmers had 132 deliveries at this time in pregnancy (2.8 per 1,000 pregnancies), while the nongrain farmers had 236 deliveries in midpregnancy (1.8 per 1,000). The authors found odds ratios (95% CI) that indicated that grain farming risk was higher after the harvest (1.8, 1.1-2.8), in seasons with a poor quality harvest (2.4, 1.5-3.8), and in pregnancies with multiple births (3.8, 1.7-8.2). These results support the hypothesis that occupational exposure to mycotoxins in grain induces labor at an early stage of pregnancy.

The neuropeptide Y (Y4) receptor is highly expressed in neurones of the rat dorsal vagal complex

Recently, the cDNA encoding the Y4 neuropeptide Y (NPY) receptor cDNA was cloned from a rat genomic library. The Y4 receptor is characterized by having a high affinity for pancreatic polypeptide (PP) and peptide YY (PYY). By using in situ hybridization histochemistry with 35S-labelled riboprobes, we have visualized the cellular expression of mRNA encoding the Y4 receptor protein in the rat dorsal vagal complex at the light microscopical level. High densities of silver grains were observed over neurones of the dorsal vagal motor nucleus, and over neurones of a subregion of the nucleus of the solitary tract known as the subnucleus gelatinosus. Furthermore, cells within the ventral margin of the area postrema expressed high levels of Y4 mRNA. These observations indicate that circulating PP and/or NPY/PYY via the blood-brain barrier-free area postrema and subpostremal area could influence neurones of the dorsal vagal complex with profound influence on numerous homeostatic mechanisms governed by this nuclear complex.

Environmental factors, reproductive history, and selective fertility in farmers' sibships

In a national study of births to farmers in Norway, grain farming was associated with short gestational age (21-24 weeks). An impact of selective fertility and maternal heterogeneity on the association was suspected but could not be assessed further in a traditional birth-based design. Thus, analyses based on the mother as the observational unit were performed. A total of 45,969 farmers with a first birth in 1967-1981 were followed for subsequent births and perinatal mortality. A perinatal loss increased farmers' likelihood to continue to another pregnancy, but this selective fertility was less dominant than in the general population due to a higher baseline fertility. The effect of the mother's reproductive history on the grain farming-midpregnancy delivery association was analyzed in 59,338 farmers with more than one single birth in 1967-1991. A history of preterm birth (< 37 weeks) in previous or subsequent pregnancies both was an independent determinant of midpregnancy delivery and also increased the effect of grain exposure. Nongrain farmers with a history of only term births had 1.3 midpregnancy deliveries per 1,000 births; grain farmers with a history of only term births had 1.8 cases per 1,000 (odds ratio (OR) 1.4, 95% confidence interval (CI) 1.0-1.9); nongrain farmers with a history of preterm birth had 6.8 cases per 1,000 (OR 5.5, 95% CI 4.0-7.6), whereas grain farmers with a history of preterm birth had 13.7 cases per 1,000 (OR 11.0, 95% CI 7.7-15.9). Selective fertility had only a marginal impact on the association. The study demonstrates that a maternally based design can contribute in the assessment of joint effects of environmental and maternal factors.

Subunit arrangement in the human 20S proteasome

In human 20S proteasomes two copies of each of seven different alpha-type and seven different beta-type subunits are assembled to form a stack of four seven-membered rings, giving the general structure alpha(1-7), beta(1-7), beta(1-7), alpha(1-7). By means of immunoelectron microscopy and chemical crosslinking of neighboring subunits, we have determined the positions of the individual subunits in the proteasome. The topography shows that for the trypsin-like, the chymotrypsin-like, and the postglutamyl cleaving activities, the pairs of beta type subunits, which are thought to form active sites, are nearest neighbors.

On-demand therapy in gastroesophageal reflux disease: a comparison of the early effects of single doses of fast-dissolving famotidine wafers and ranitidine tablets

In this double-masked, double-dummy, randomized, single crossover study, we compared single doses of a fast-dissolving wafer formulation of famotidine with a conventional tablet formulation of ranitidine in patients with gastroesophageal reflux disease (GERD). Patient preference time until symptomatic relief, and predictive characteristics of early responders were assessed. Eligible patients had a clinical diagnosis of GERD and symptoms of GERD of sufficient severity to require relief. The study treatment was one dose of famotidine (20-mg wafer) and one dose of ranitidine (150-mg tablet), which were given in a randomized order and taken as needed. The patients were instructed to measure the symptomatic effects on a seven-point categorical scale (1 = worse to 7 = free of symptoms) at 15, 30, 45, 60, 120, and 180 minutes. After the clinical phase of the trial, the patients indicated their global assessment of efficacy and their preference for the wafer or the tablet. Of the 829 patients who completed the study, significantly more preferred the wafer to the tablet. While there was no significant difference in the global assessment of efficacy, the famotidine wafer provided significantly better relief than the ranitidine tablet during the first hour after dosing. However, at 120 and 180 minutes, the degree of relief was similar for the two drugs. The time until a clinically significant effect was also similar for the two drugs, and approximately one half of the patients experienced such improvement within 3 hours. Multivariate analyses disclosed no predictive characteristics of early symptomatic effect.

A model phage display subtraction method with potential for analysis of differential gene expression

In order to establish a subtractive procedure that makes it possible to enrich selectively phage displayed antibodies directed against proteins constituting a difference between two populations of cells, a competitive selection strategy utilising two solid phases was developed and tested. Antibodies recognising a defined difference between two otherwise identical protein mixtures were isolated and their specificity confirmed. To test further the efficacy of selection inhibition during the competitive selections, selections towards a total cell extract were performed with and without competition from the same extract. An analysis of the resulting phage antibodies confirmed the subtractive nature of the system described.