The changing character of regulation: a comparison of Europe and the United States

European and U.S. regulatory policies have changed considerably over the past 30 years. In Europe, since the mid-1980s, consumer and environmental regulation has become more politically salient and regulations have by and large become stricter. On the other hand, in the United States consumer and environmental issues have become less salient and contentious, and regulations have not become (comparatively) stricter. This apparent "flip-flop" of regulatory systems has not been analyzed in much detail to date. This perspective is an attempt to analyze some examples in which it has occurred and identifies one possible cause--namely, credibility.

Oxytocin antagonists: clinical and scientific considerations

Preterm delivery is the largest cause of perinatal mortality and morbidity, yet the treatment of preterm labour has not been demonstrated to improve outcome. The reasons are numerous and complex, but they include a failure to understand the mechanism(s) of preterm labour, the multitude of different causes, the difficulty in diagnosis and the problems of outcome measurement in clinical trials. Recently, an oxytocin antagonist (atosiban) has been introduced into clinical practice in Europe. Although it may be an effective tocolytic, a beneficial effect on perinatal outcome has not been demonstrated. Atosiban has an effect at both oxytocin and vasopressin (V(1a)) receptors, which (assuming efficacy) raises the question as to whether oxytocin or vasopressin V(1a) antagonism is required for tocolysis. This review examines the rationale for tocolysis in preterm labour, the evidence for administration of atosiban and the role for oxytocin, vasopressin and their receptors in the onset of labour. Experimental Physiology (2001) 86.2, 297-302.

Characterization of an antibody to the human melatonin mt1 receptor

Melatonin acts via high affinity, G-protein coupled, seven transmembrane domain receptors. To precisely localize these receptors, antibodies were raised in chickens against a 15 amino acid fragment at the intracellular C-terminal region of the human melatonin receptor subtype mt1 (DSSNDVADRVKWKPS, mt(1338-352)). A chimeric form of the receptor with a hydrophilic Flag peptide (DYKDDDDK) in sequence with the extracellular N-terminus (Flag-mt1) was generated by polymerase chain reaction and expressed in mammalian cell lines. An IgY antibody (Y31), which gave high antibody titres by enzyme-linked immunosorbent assay, was used to localize Flag-mt1 in stably transfected cells by immunofluoresence. Flag-mt1 localization with Y31 was identical to that obtained with the M5 antibody directed against the Flag epitope and was mainly localized to the Golgi apparatus with some staining at the cell surface. No staining was seen in untransfected cells with either antibody. Y31 staining was abolished using antibody preabsorbed with peptide antigen. Y31 immunofluorescence in fetal human kidney sections was restricted to nephrogenic regions and matched that of 2-((125)I)iodomelatonin binding and mt1 gene expression by in situ hybridization. Y31 was used to immunoprecipitate biotinylated membrane proteins from Flag-mt1 stably transfected and untransfected CHO cells. Western blotting of immunoprecipitated proteins revealed two major bands specific to stably transfected cells, one at 63 kDa and one at 86 kDa. The first band almost certainly corresponds to the glycosylated form of Flag-mt1 and the second band to receptor dimers. Thus, Y31 antibody is suitable for use in detecting the human mt1 receptor subtype in tissues and in transfected cells.

Mutant torsinA, responsible for early-onset torsion dystonia, forms membrane inclusions in cultured neural cells

Early-onset torsion dystonia is a hereditary movement disorder thought to be caused by decreased release of dopamine into the basal ganglia, without apparent neuronal degeneration. Recent cloning of the gene responsible for this disease, TOR1A (DYT1), identified the encoded protein, torsinA, as a member of the AAA+ superfamily of chaperone proteins and revealed highest levels of expression in dopaminergic neurons in human brain. Most cases of this disease are caused by a deletion of one glutamic acid residue in the C-terminal region of the protein. Antibodies generated against torsinA revealed expression of a predominant immunoreactive protein species similar to the predicted size of 37.8 kDa in neural, glial and fibroblastic lines by western blot analysis. This protein is N-glycosylated with high mannose content and not, apparently, phosphoryl-ated. Overexpression of torsinA in mouse neural CAD cells followed by immunocytochemistry, revealed a dramatically different pattern of distribution for wild-type and mutant forms of the protein. The wild-type protein was found throughout the cytoplasm and neurites with a high degree of co-localization with the endoplasmic reticulum (ER) marker, protein disulfide isomerase. In contrast, the mutant protein accumulated in multiple, large inclusions in the cytoplasm around the nucleus. These inclusions were composed of membrane whorls, apparently derived from the ER. If disrupted processing of the mutant protein leads to its accumulation in multilayer membranous structures in vivo, these may interfere with membrane trafficking in neurons.

Expression of cyclo-oxygenase types-1 and -2 in human fetal membranes throughout pregnancy

Human labour is associated with increased prostaglandin synthesis within the fetal membranes. We have studied the expression of the two isoforms of the central prostaglandin synthetic enzyme, cyclo-oxygenase (COX-1 and COX-2), in human fetal membranes throughout pregnancy, at mRNA, protein and activity levels. COX-1 mRNA expression was low in human amnion and chorion-decidua and did not change with gestational age. COX-2 mRNA expression in fetal membranes increased with gestational age, with significant up-regulation prior to the onset of labour and in association with labour. Protein concentrations of COX-1 did not change, whilst concentrations of COX-2 increased from the first to the third trimester. COX activity increased with gestational age and in association with labour, although prostaglandin production in fetal membranes collected after labour was reduced, suggesting reduced substrate supply. These data suggest that it is up-regulation of COX-2, rather than of COX-1, which mediates increased prostaglandin synthesis within the fetal membranes at term. Much of the increase in COX-2 expression precedes the onset of labour, suggesting that it is a cause, rather than a consequence, of labour.

Leptin receptor and neuropeptide Y gene expression in the sheep brain

Leptin, a protein secretory product of adipocytes, is important in appetite control, energy balance and reproduction. In rodents, the physiological effects of leptin are centrally mediated, in part via the neuropeptide Y (NPY) system in the hypothalamus. The role of leptin in ruminants, where appropriate nutrition and reproductive status are of major economic concern, is largely unknown. To elucidate the function of leptin in sheep we have investigated putative sites of action for leptin in the brain and pituitary gland using both in-situ hybridization to detect expression of the signalling form of the leptin receptor (OB-Rb) and in-vitro autoradiography using (125I)leptin to detect sites of specific leptin binding. OB-Rb gene expression occurred in the hippocampus, cerebral cortex, preoptic area, stria terminalis and choroid plexus, and within the hypothalamus in the paraventricular (PVN), ventromedial (VHM) and arcuate (ARC) nuclei. OB-Rb gene expression in the ovine pituitary gland was not detected by in-situ hybridization. Sites of OB-Rb and NPY gene expression were compared using both in-situ hybridization on adjacent sections containing the arcuate and ventromedial nuclei, and dual in-situ hybridization on sections containing these areas. In serial sections, OB-Rb expression was found to correspond closely with that of NPY over the arcuate nuclei. Using dual in-situ hybridization, NPY expressing neurones in the arcuate nuclei were also positive for OB-Rb gene expression. Therefore, it appears that leptin may partly act via OB-Rb located on NPY neurones in the sheep hypothalamus as in the rodent.

Efficacy and tolerability of 0.5% timolol maleate ophthalmic gel-forming solution QD compared with 0.5% levobunolol hydrochloride BID in patients with open-angle glaucoma or ocular hypertension

We compared the efficacy of timolol maleate ophthalmic gel-forming solution 0.5% QD with that of levobunolol hydrochloride 0.5% BID, as measured by change in intraocular pressure (IOP), effect on heart rate, and ocular tolerability. The study had a positive-controlled, double-masked, randomized, multicenter, 12-week, two-period (6 weeks each), crossover design. One hundred fifty-two patients with open-angle glaucoma or ocular hypertension were randomized to receive either timolol maleate gel-forming solution QD or levobunolol BID for 6 weeks, followed by a crossover to the alternate treatment. IOP and heart rate were measured at morning trough and peak during weeks 3, 6, 9, and 12. Timolol maleate gel-forming solution QD was comparable to levobunolol BID in reducing IOP at peak and trough. Although the effects on peak heart rate were similar between the two medications, the effect on trough heart rate of timolol maleate gel-forming solution QD was significantly less than that of levobunolol BID (P = 0.001). The incidence of ocular burning and stinging was comparable between the two treatments. Patients experienced significantly more blurred vision when using timolol maleate gel-forming solution than when using levobunolol (P = 0.013). Overall, more patients experienced at least one adverse event when using timolol maleate gel-forming solution. Timolol maleate gel-forming solution QD is as efficacious in reducing IOP as levobunolol BID.

Changes in the expression of the type-2 but not the type-1 cyclo-oxygenase enzyme in chorion-decidua with the onset of labour

OBJECTIVE

To determine the relative expression of cyclo-oxygenase (COX)-1 and COX-2 in the chorion-decidual part of human fetal membranes following delivery at term and to identify any changes in expression associated with labour.

METHODS

Fetal membranes were collected from 12 term pregnancies before labour following elective caesarean section and from 12 spontaneous vaginal deliveries. Expression of COX-1 and COX-2 mRNA was measured using a previously validated quantitative RT-PCR assay.

RESULTS

COX-2 expression exceeded that of COX-1 by approximately eight-fold. COX-1 expression did not change but COX-2 expression was found to increase four-fold with labour.

CONCLUSIONS

Chorion-decidua has the capacity to contribute to the increase in prostaglandin synthesis within the uterus associated with labour. As in the amnion, it is COX-2 and not COX-1 which is upregulated with labour. COX-2 selective anti-prostaglandins should therefore be as effective as nonselective drugs in inhibition of fetal membrane prostaglandin synthesis.

Treatment of advanced pancreatic adenocarcinoma with 5-FU, leucovorin, interferon-alpha-2b, and cisplatin

Previous laboratory and clinical studies support the ability of interferon (IFN) to enhance the antitumor properties of chemotherapy agents, including cisplatin and 5-fluorouracil (5-FU). A phase I-II clinical trial was initiated to treat several tumor types with IFN-alpha-2b, cisplatin, 5-FU, and leucovorin (LV), given daily for 5 days of a 28-day cycle. Because of preliminary results, this was continued as a phase II trial in 18 patients with metastatic adenocarcinoma of the pancreas. Each treatment day consisted of IFN 5 million u/m2 s.c. (maximum, 10 million U), CDDP 20 mg/m2 i.v. over 1 h, LV 20 mg/m2 i.v.p., and 5-FU 250-275 mg/m2 i.v.p. All patients had measurable disease with no prior chemotherapy for metastatic disease, and all had an Eastern Cooperative Oncology Group (ECOG) performance status of 1. Six of the 16 patients evaluable for response had partial responses (PRs) (37.5%) with a median response duration of 4 months, and all responding patients survived > or = 8 months. Median survival of all 18 treated patients was 5 months. Severe gastrointestinal toxicity (nausea, diarrhea, or requirement for i.v. hydration) was common. Grade 4 hematologic toxicity was seen in six patients. The response rate observed is promising and supports the concept that IFN may potentiate the effects of standard chemotherapy agents. However, the toxicities observed with this dosage schedule were considerable and further studies are needed to develop a less toxic regimen.

Computing illumination-invariant descriptors of spatially filtered color image regions

Spatial filters provide a useful and efficient means of analyzing an input color image into components that capture different spatial properties. Representations based on spatial filtering have restricted usefulness for recognition, however, because the output of a spatial filter across an image depends on the scene illumination conditions. We use a physically accurate linear model for spectral reflectance to derive invariants of distributions in spatially filtered color images that do not depend on the scene illumination. These invariants can be used for the illumination-invariant recognition of regions following an arbitrary linear filtering operation. We describe a method for illumination correction based on color distributions and introduce an illumination change consistency constraint that is useful for verifying matches obtained using the invariants. We show, using a set of classification experiments, that the filtered distribution invariants can significantly improve the capability of a recognition system in environments where illumination cannot be controlled.

Sialylation of intestinal microvillar membranes in newborn, sucking and weaned pigs

Affinity cytochemistry and biochemistry revealed distinctive temporal changes in the expression of sialylated and compositionally related membrane glycoconjugates in the pig small intestine between birth and weaning. The expression of membrane NeuAc alpha 2,6 moieties, recognized by Sambucus nigra agglutinin-1, was high in newborn pigs, declined slightly during sucking and was very low in weaned animals. Conversely, the expression of membrane NeuAc alpha 2.3 moieties, recognized by Maackia amurensis agglutinin-2, was low at birth but higher in sucking and weaned animals. Histoblood group O- and A-antigen expression was first detected in a minority of sucking pigs, but was evident in all weaned pigs examined. Lactase glycoforms were isolated from solubilized microvillar membranes of newborn and weaned pigs. The newborn (predominantly alpha 2,6-sialylated) and weaned (predominantly alpha 1,2-fucosylated) glycoforms exhibited similar specific activity, indicating that postnatal lactase decline in the pig intestine is unrelated to temporal changes in membrane sialylation and fucosylation.