Biotic and abiotic factors determining the distribution of two prawn species: Palaemon adspersus and P. squilla

Summary The reasons behind the absence of the prawn Palaemon adspersus and the presence of P. squilla in rockpools and on bare sand bottoms were studied. Some maximal abundances in different habitats are given. Introduction experiments into natural and artificial rockpools and measurements of tolerance towards low oxygen levels showed that nocturnal hypoxia excluded P. adspersus which was significantly more sensitive to oxygen depletion. Respiration rates measured by the closed-bottle method showed no interspecific difference.On bare sand bottoms P. aspersus was probably excluded by predators, since predator exclusion experiments in cages and predator inclusion experiments in containers showed that P. adaspersus was more vulnerable to predation than P. squilla.The costs for being able to cope with a wide array of habitat in P. squilla are probably balanced by the benefits of access to habitats such as intertidal rockpools, very shallow bottoms and deeper sand bottoms. Tolerance towards abiotic factors extends its habitat range upwards into shallower waters, and tolerance towards biotic factors, i.e. predation, extends it downwards.     

Prevalence of primary and secondary hypertension: studies in a random population sample.

The prevalence of primary and secondary hypertension was determined in a random sample of 7455 Swedish men aged 47 to 54 years. Three hundred and sizty-one men were undergoing treatment for hypertension. Seven hundred and ninety-eight men who had blood pressures above 175/115 mm Hg at preliminary screening were recalled for further blood pressure measurements. Those on treatment and all the untreated men whose blood pressures were still over 175/115 mm Hg then underwent extensive investigation for secondary hypertension. Renal parenchymal hypertension was found in 25 (3-6%) patients, renovascular hypertension in four (0-6%), and other forms of secondary hypertension in 11 (1-6%). The investigation led to surgical treatment in only two cases (0-3%). The low prevalence of secondary hypertension, especially surgically curable forms of hypertension, makes routine screening for these cases unnecessary, at least when patients with hypertension have been found at screening. These data must be taken into account in planning community control programmes in hypertension.     

Effect of different carbon sources on the production of succinic acid using metabolically engineered Escherichia coli

Succinic acid (SA) is an important platform molecule in the synthesis of a number of commodity and specialty chemicals. In the present work, dual-phase batch fermentations with the E. coli strain AFP184 were performed using a medium suited for large-scale industrial production of SA. The ability of the strain to ferment different sugars was investigated. The sugars studied were sucrose, glucose, fructose, xylose, and equal mixtures of glucose and fructose and glucose and xylose at a total initial sugar concentration of 100 g L-1. AFP184 was able to utilize all sugars and sugar combinations except sucrose for biomass generation and succinate production. For sucrose as a substrate no succinic acid was produced and none of the sucrose was metabolized. The succinic acid yield from glucose (0.83 g succinic acid per gram glucose consumed anaerobically) was higher than the yield from fructose (0.66 g g-1). When using xylose as a carbon source, a yield of 0.50 g g-1 was obtained. In the mixed-sugar fermentations no catabolite repression was detected. Mixtures of glucose and xylose resulted in higher yields (0.60 g g-1) than use of xylose alone. Fermenting glucose mixed with fructose gave a lower yield (0.58 g g-1) than fructose used as the sole carbon source. The reason is an increased pyruvate production. The pyruvate concentration decreased later in the fermentation. Final succinic acid concentrations were in the range of 25-40 g L-1. Acetic and pyruvic acid were the only other products detected and accumulated to concentrations of 2.7-6.7 and 0-2.7 g L-1. Production of succinic acid decreased when organic acid concentrations reached approximately 30 g L-1. This study demonstrates that E. coli strain AFP184 is able to produce succinic acid in a low cost medium from a variety of sugars with only small amounts of byproducts formed.     

Screening for carcinoma of the prostate by digital rectal examination in a randomly selected population.

OBJECTIVE--To study the acceptability, costs, psychosocial consequences, and organisation of screening for carcinoma of the prostate. DESIGN--A randomly selected population was personally invited for digital rectal examination by a urologist and a general practitioner. Further examinations were performed if induration was felt. Each man completed a questionnaire on his response to the examination. SETTING--General practices in the area of Norrköping. PATIENTS--1494 Men aged 50-69 randomly selected from a population of 9026. MAIN OUTCOME MEASURE--Prostates having a firm nodular consistency. RESULTS--Carcinoma of the prostate was suspected in 45 of 1163 patients examined; in 10 by the general practitioners, in 10 by the urologists, and in 25 by both. Forty four men had a fine needle aspiration biopsy, and carcinomas were found in 13 cases. Of these, one had been suspected by the general practitioner, four by urologists, and eight by both. The cost for each man was 11.60 pounds, and the cost for each case of carcinoma detected and treated by potentially curative methods was 2477 pounds. Of the 13 men with carcinoma, 10 underwent radical prostatectomy and one radiotherapy. One man had advanced disease and was given endocrine treatment, another was not treated. Only 193 men felt distress during the initial examination. Of the 44 men who had an aspiration biopsy, 25 experienced anxiety. CONCLUSIONS--Screening for carcinoma of the prostate by a urologist or a general practitioner using digital rectal examination is a cost effective method of early diagnosis. Whether such screening leads to prolonged survival, however, remains doubtful.     

Double-strand break DNA repair genotype predictive of later mortality and cancer incidence in a cohort of non-smokers

We followed-up for mortality and cancer incidence 1088 healthy non-smokers from a population-based study, who were characterized for 22 variants in 16 genes involved in DNA repair pathways. Follow-up was 100% complete. The association between polymorphism and mortality or cancer incidence was analyzed using Cox Proportional Hazard regression models. Ninety-five subjects had died in a median follow-up time of 78 months (inter-quartile range 59-93 months). None of the genotypes was clearly associated with total mortality, except variants for two Double-Strand Break DNA repair genes, XRCC3 18067 C>T (rs#861539) and XRCC2 31479 G>A (rs#3218536). Adjusted hazard ratios were 2.25 (1.32-3.83) for the XRCC3 C/T genotype and 2.04 (1.00-4.13) for the T/T genotype (reference C/C), and 2.12 (1.14-3.97) for the XRCC2 G/A genotype (reference G/G). For total cancer mortality, the adjusted hazard ratios were 3.29 (1.23-7.82) for XRCC3 C/T, 2.84 (0.81-9.90) for XRCC3 T/T and 3.17 (1.21-8.30) for XRCC2 G/A. With combinations of three or more adverse alleles, the adjusted hazard ratio for all cause mortality was 17.29 (95% C.I. 8.13-36.74), and for all incident cancers the HR was 5.28 (95% C.I. 2.17-12.85). Observations from this prospective study suggest that polymorphisms of genes involved in the repair of DNA double-strand breaks significantly influence the risk of cancer and non-cancer disease, and can influence mortality.     

Melanocortin-4 receptors expressed by cholinergic neurons regulate energy balance and glucose homeostasis

Melanocortin-4 receptor (MC4R) mutations cause dysregulation of energy balance and hyperinsulinemia. We have used mouse models to study the physiological roles of extrahypothalamic MC4Rs. Re-expression of MC4Rs in cholinergic neurons (ChAT-Cre, loxTB MC4R mice) modestly reduced body weight gain without altering food intake and was sufficient to normalize energy expenditure and attenuate hyperglycemia and hyperinsulinemia. In contrast, restoration of MC4R expression in brainstem neurons including those in the dorsal motor nucleus of the vagus (Phox2b-Cre, loxTB MC4R mice) was sufficient to attenuate hyperinsulinemia, while the hyperglycemia and energy balance were not normalized. Additionally, hepatic insulin action and insulin-mediated suppression of hepatic glucose production were improved in ChAT-Cre, loxTB MC4R mice. These findings suggest that MC4Rs expressed by cholinergic neurons regulate energy expenditure and hepatic glucose production. Our results also provide further evidence of the dissociation in pathways mediating the effects of melanocortins on energy balance and glucose homeostasis.     

Sexual signals and mating patterns in Syngnathidae

Male pregnancy in the family Syngnathidae (pipefishes, seahorses and seadragons) predisposes males to limit female reproductive success; sexual selection may then operate more strongly on females and female sexual signals may evolve (sex-role reversal). A bewildering array of female signals has evolved in Syngnathids, e.g. skin folds, large body size, colouration, markings on the body and elaborate courtship. These female sexual signals do not seem quantitatively or qualitatively different from those that evolve in males in species with conventional sex roles where males provide females or offspring with direct benefits. In several syngnathid species, males also evolve ornaments, females are choosy in addition to being competitive and males compete as well as choosing partners. Thus, sex roles form a continuum, spanning from conventional to reversed within this group of fishes. Cases are presented here suggesting that stronger sexual selection on females may be most extreme in species showing classical polyandry (one male mates with several females, such as many species where males brood their eggs on the trunk), intermediate in polygynandrous species (males and females both mate with more than one partner, as in many species where males brood their eggs on the tail) and least extreme, even exhibiting conventional sex roles, in monogamous species (one male mates solely with one female, as in many seahorses and tropical pipefishes). At the same time caution is needed before unanimously establishing this pattern: first, the connection between mating patterns, strength of sexual selection, sex roles and ornament expression is far from simple and straightforward, and second, knowledge of the actual morphology, ecology and behaviour of most syngnathid species is scanty. Basically only a few Nerophis, Syngnathus and Hippocampus species have been studied in any detail. It is known, however, that this group of fishes exhibits a remarkable variation in sex roles and ornamentation, making them an ideal group for the study of mating patterns, sexual selection and sexually selected signals.     

Increased Inflammatory Response in Cytomegalovirus Seropositive Patients with Alzheimer’s Disease

Alzheimer’s disease (AD) has been associated with increased local inflammation in the affected brain regions, and in some studies also with elevated levels of proinflammatory cytokines in peripheral blood. Cytomegalovirus (CMV) is known to promote a more effector-oriented phenotype in the T-cell compartment, increasing with age. The aim of this study was to investigate the inflammatory response of peripheral blood mononuclear cells (PBMCs) from AD patients and non-demented (ND) controls. Using a multiplex Luminex xMAP assay targeting GM-CSF, IFN-γ, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IP-10 and TNF-α, cytokine profiles from PBMCs were analysed after stimulation with anti-CD3/CD28 beads, CMV pp65 peptide mix or amyloid β (Aβ) protofibrils, respectively. CMV seropositive AD subjects presented with higher IFN-γ levels after anti-CD3/CD28 and CMV pp65 but not after Aβ stimulation, compared to CMV seropositive ND controls. When analysing IFN-γ response to anti-CD3/CD28 stimulation on a subgroup level, CMV seropositive AD subjects presented with higher levels compared to both CMV seronegative AD and CMV seropositive ND subjects. Taken together, our data from patients with clinically manifest AD suggest a possible role of CMV as an inflammatory promoter in AD immunology. Further studies of AD patients at earlier stages of disease, could provide better insight into the pathophysiology.     

Co-delivery of antigen and IL-12 by Venezuelan equine encephalitis virus replicon particles enhances antigen-specific immune responses and antitumor effects

We recently demonstrated that Venezuelan equine encephalitis virus-based replicon particle (VRPs) encoding tumor antigens could break tolerance in the immunomodulatory environment of advanced cancer. We hypothesized that local injection of VRP-expressing interleukin-12 (IL-12) at the site of injections of VRP-based cancer vaccines would enhance the tumor-antigen-specific T cell and antibody responses and antitumor efficacy. Mice were immunized with VRP encoding the human tumor-associated antigen, carcinoembryonic antigen (CEA) (VRP-CEA(6D)), and VRP-IL-12 was also administered at the same site or at a distant location. CEA-specific T cell and antibody responses were measured. To determine antitumor activity, mice were implanted with MC38-CEA-2 cells and immunized with VRP-CEA with and without VRP-IL-12, and tumor growth and mouse survival were measured. VRP-IL-12 greatly enhanced CEA-specific T cell and antibody responses when combined with VRP-CEA(6D) vaccination. VRP-IL-12 was superior to IL-12 protein at enhancing immune responses. Vaccination with VRP-CEA(6D) plus VRP-IL-12 was superior to VRP-CEA(6D) or VRP-IL-12 alone in inducing antitumor activity and prolonging survival in tumor-bearing mice. Importantly, local injection of VRP-IL-12 at the VRP-CEA(6D) injection site provided more potent activation of CEA-specific immune responses than that of VRP-IL-12 injected at a distant site from the VRP-CEA injections. Together, this study shows that VRP-IL-12 enhances vaccination with VRP-CEA(6D) and was more effective at activating CEA-specific T cell responses when locally expressed at the vaccine site. Clinical trials evaluating the adjuvant effect of VRP-IL-12 at enhancing the immunogenicity of cancer vaccines are warranted.