Fecal cortisol metabolite levels in free-ranging North American red squirrels: Assay validation and the effects of reproductive condition

Patterns in stress hormone (glucocorticoid: GC) levels and their relationship to reproductive condition in natural populations are rarely investigated. In this study, we (1) validate an enzyme-immunoassay to measure fecal cortisol metabolite (FCM) levels in North American red squirrels (Tamiasciurus hudsonicus), and (2) examine relationships between FCM levels and reproductive condition in a free-ranging red squirrel population. Injected radiolabeled cortisol was entirely metabolized and excreted in both the urine (mean ± SE; 70.3 ± 0.02%) and feces (29.7 ± 0.02%), with a lag time to peak excretion in the feces of 10.9 ± 2.3 h. Our antibody reacted with several cortisol metabolites, and an adrenocorticotropic injection significantly increased FCM levels above baseline levels at 8 h post-injection. Relative to baseline levels, manipulation by handling also tended to increase FCM levels at 8 h post-manipulation, but this difference was not significant. FCM levels did not differ significantly between samples frozen immediately and 5 h after collection. Reproductive condition significantly affected FCM levels in free-ranging females (pregnant > lactating > post-lactating > non-breeding) but not males (scrotal testes vs. abdominal testes). Among females with known parturition dates, FCM levels increased during gestation, peaked at parturition, and declined during lactation. The difference between pregnant and lactating females was therefore dependent upon when the fecal samples were obtained during these periods, suggesting caution in categorizing reproductive stages. This study demonstrates the utility of fecal hormone metabolite assays to document patterns of glucocorticoid levels in free-ranging animals.     

Thalidomide attenuates nitric oxide-driven angiogenesis by interacting with soluble guanylyl cyclase

Background and purpose:

Nitric oxide (NO) promotes angiogenesis by activating endothelial cells. Thalidomide arrests angiogenesis by interacting with the NO pathway, but its putative targets are not known. Here, we have attempted to identify these targets.

Experimental approach:

Cell-based angiogenesis assays (wound healing of monolayers and tube formation in ECV304, EAhy926 and bovine arterial endothelial cells), along with ex vivo and in vivo angiogenesis assays, were used to explore interactions between thalidomide and NO. We also carried out in silico homology modelling and docking studies to elucidate possible molecular interactions of thalidomide and soluble guanylyl cyclase (sGC).

Key results:

Thalidomide inhibited pro-angiogenic functions in endothelial cell cultures, whereas 8-bromo-cGMP, sildenafil (a phosphodiesterase inhibitor) or a NO donor [sodium nitroprusside (SNP)] increased these functions. The inhibitory effects of thalidomide were reversed by adding 8-bromo-cGMP or sildenafil, but not by SNP. Immunoassays showed a concentration-dependent decrease of cGMP in endothelial cells with thalidomide, without affecting the expression level of sGC protein. These results suggested that thalidomide inhibited the activity of sGC. Molecular modelling and docking experiments revealed that thalidomide could interact with the catalytic domain of sGC, which would explain the inhibitory effects of thalidomide on NO-dependent angiogenesis.

Conclusion and implications:

Our results showed that thalidomide interacted with sGC, suppressing cGMP levels in endothelial cells, thus exerting its anti-angiogenic effects. These results could lead to the formulation of thalidomide-based drugs to curb angiogenesis by targeting sGC.     

Prevalence of herpes simplex type 2 and syphilis serology among young adults in a rural Gambian community

OBJECTIVES: To estimate prevalence and risk factors for herpes simplex 2 (HSV2) positivity, syphilis and Chlamydia trachomatis infection among rural people aged 15-34 in the Gambia. METHODS: Questionnaires and serum samples were collected from 1076 men and women aged 15-34 during a cross sectional prevalence survey in a rural area of the Gambia. Sera were screened for antibodies to herpes simplex virus type 2 (HSV2), and for syphilis using Treponema pallidum haemagglutination assay (TPHA) and rapid plasma reagin (RPR) tests. Urine was tested by polymerase chain reaction (PCR) for C trachomatis infection. RESULTS: 28% of women and 5% of men were HSV2 ELISA positive; 10% of women and 2% of men were TPHA positive; and 7% of women and 1% of men were both RPR and TPHA positive. Out of 1030 urine sample tested only six were positive for C trachomatis. 7% of those who reported never having sex were positive for one or other of these tests. Prevalences of all STIs increased with age and were higher in women than men. Women were much less likely than men to seek treatment for STI symptoms at a health centre. Married people were at increased risk of an STI compared with single people. Jola and Fula women had a higher prevalence of HSV2 than women from other ethnic groups, and Fulas also had a higher prevalence of RPR/TPHA positivity. The limited number of sexual behaviour questions were not significantly associated with STIs after adjustment for age, marital status, and ethnic group. CONCLUSIONS: The prevalences of the ulcerative infections HSV2 and syphilis in this population are a cause for concern. In a setting where HIV1 prevalence remains low this indicates an urgent need for STI control and behaviour change programmes to prevent an HIV epidemic. Concerns about the validity of reported sexual behaviour data high light the necessity of biological markers in the evaluation of behaviour change programmes.     

Use of complementary and alternative medicine by patients admitted to a surgical unit in Scotland

INTRODUCTION

Within the UK there are 50,000 practitioners of complementary medicine. Five million people have consulted such practitioners in one year. The aim of this study was to explore the use of complementary and alternative medicine (CAM) in patients attending general, vascular and cardiothoracic units at a regional Scottish centre.

PATIENTS AND METHODS

A questionnaire was administered to 450 patients attending the units over an 8-week period. The questionnaire consisted of demographic sections, a listing of 48 herbal preparations and alternative therapies, reasons for use and opinions on efficacy.

RESULTS

A total of 430 patients completed questionnaires (95%); age and sex were equally distributed over the sample. Of respondents, 68% (291 patients) had ever used CAM; 46% had used CAM in the preceding year. Half had used herbal preparations only, 13% non-herbal treatments and 35% both types of therapy. Only 10% were using CAM for the condition that led to their hospital admission. Two-thirds failed to inform their family physician about their use of CAM.

CONCLUSIONS

Despite concerns regarding the efficacy, safety and cost-effectiveness of complementary medicine, use amongst surgical patients is common.     

Influence of clinical status on the association between plasma total and unbound bilirubin and death or adverse neurodevelopmental outcomes in extremely low birth weight infants

Objectives: To assess the influence of clinical status on the association between total plasma bilirubin and unbound bilirubin on death or adverse neurodevelopmental outcomes at 18–22 months corrected age in extremely low birth weight infants. Method: Total plasma bilirubin and unbound bilirubin were measured in 1101 extremely low birth weight infants at 5 ± 1 days of age. Clinical criteria were used to classify infants as clinically stable or unstable. Survivors were examined at 18–22 months corrected age by certified examiners. Outcome variables were death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death prior to follow‐up. For all outcomes, the interaction between bilirubin variables and clinical status was assessed in logistic regression analyses adjusted for multiple risk factors. Results: Regardless of clinical status, an increasing level of unbound bilirubin was associated with higher rates of death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss and death before follow‐up. Total plasma bilirubin values were directly associated with death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death before follow‐up in unstable infants, but not in stable infants. An inverse association between total plasma bilirubin and death or cerebral palsy was found in stable infants. Conclusions: In extremely low birth weight infants, clinical status at 5 days of age affects the association between total plasma bilirubin and death or adverse neurodevelopmental outcomes at 18–22 months of corrected age. An increasing level of UB is associated a higher risk of death or adverse neurodevelopmental outcomes regardless of clinical status. Increasing levels of total plasma bilirubin are directly associated with increasing risk of death or adverse neurodevelopmental outcomes in unstable, but not in stable infants.     

The use of a novel tobacco-substitute sheet and smoke dilution to reduce toxicant yields in cigarette smoke

The Institute of Medicine encouraged the pursuit and development of potential reduced-exposure products, tobacco products that substantially reduce exposure to one or more tobacco toxicants and can reasonably be expected to reduce the risk of one or more specific diseases or other adverse health effects. One approach to reducing smoke toxicant yields is to dilute the smoke with glycerol. We report chemical, biological and human exposure data related to experimental cigarettes containing up to 60% of a novel glycerol containing “tobacco-substitute” sheet. Analysis of mainstream smoke from experimental cigarettes showed reductions in yields of most measured constituents, other than some volatile species. In vitro toxicological tests showed reductions in the activity of smoke particulates in proportion to their glycerol content. Human exposure to nicotine was reduced by a mean of 18% as determined by filter studies and by 14% using 24 h urinary biomarker analysis. Smoke particulate exposures were reduced by a mean of 29% in filter studies and NNK exposure by similar amounts based on urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol concentrations. These results show that reducing exposure to some smoke toxicants is possible using a tobacco-substitute sheet, although some smoke toxicants, and the sensory attributes of the smoke, remain as technical challenges.     

Acute cervico-facial oedema and loss of consciousness following ingestion of barracuda fish

A young male presented with acute cervico-facial swelling and loss of consciousness, following ingestion of barracuda flesh. He recovered after administration of anti-histamines and steroids. Toxicity associated with barracuda is discussed.     

In vitro cultivation of Cryptosporidium parvum and screening for anticryptosporidial drugs.

Sporozoites of Cryptosporidium parvum which were excysted in vitro from oocysts isolated from calves or patients with acquired immune deficiency syndrome underwent development in monolayers of the mouse fibroblast cell line L929. Asexual multiplication occurred, with the maximum numbers of parasites usually being observed between 24 and 48 h after infection. Gametocytes were also found, but their numbers were relatively small compared with those of the asexual stages. A study was made of the effect on parasite development of 20 antimicrobial agents, most of which were anticoccidial or antimalarial agents. The majority of the drugs had a limited inhibitory effect on parasite development, but usually only at high concentrations. The two most active drugs were monensin and halofuginone, which reduced parasite multiplication by more than 90% at high concentrations. In the case of monensin, however, inhibition of parasite development at higher concentrations was due, at least in part, to a toxic effect of the drug on the host cells.